Publications
We have compiled a selection of scientific papers that illustrate some applications of our instruments, including in combination with each other. You can filter the list by type of instrument and type of measurement, or search for keywords.
We would also highlight the recent Special Issue of Photosynthetica as a source of research applications in the field of chlorophyll fluorescence.
| Measurement | Instrument | Journal | Principal Author | Institute | Department | Country | Date | Title | Abstract | Keyword 1 | Keyword 2 | Keyword 3 | Keyword 4 | Keyword 5 | Keyword 6 | Keyword 7 | Keyword 8 | Keyword 9 | Keyword 10 | Keywords |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chlorophyll fluorescence | Pocket PEA | Ecotoxicology and Environmental Safety | Romária Pereira de Araújo | State University of Santa Cruz | Department of biological sciences | Brazil | 2017 | Photosynthetic, antioxidative, molecular and ultrastructural responses of young cacao plants to Cd toxicity in the soil | Cadmium (Cd) is a highly toxic metal for plants, even at low concentrations in the soil. The annual production of world cocoa beans is approximately 4 million tons. Most of these fermented and dried beans are used in the manufacture of chocolate. Recent work has shown that the concentration of Cd in these beans has exceeded the critical level (0.6 mg kg−1 DM). The objective of this study was to evaluate the toxicity of Cd in young plants of CCN 51 cacao genotype grown in soil with different concentrations of Cd (0, 0.05 and 0.1 g kg−1 soil) through photosynthetic, antioxidative, molecular and ultrastructural changes. The increase of Cd concentration in the soil altered mineral nutrient absorption by competition or synergism, changed photosynthetic activity caused by reduction in chloroplastidic pigment content and damage to the photosynthetic machinery evidenced by the Fv/Fm ratio and expression of the psbA gene and increased GPX activity in the root and SOD in leaves. Additionally, ultrastructural alterations in roots and leaves were also evidenced with the increase of the concentration of Cd in the soil, whose toxicity caused rupture of biomembranes in root and leaf cells, reduction of the number of starch grains in foliar cells, increase of plastoglobules in chloroplasts and presence of multivesiculated bodies in root cells. It was concluded, therefore, that soil Cd toxicity caused damage to the photosynthetic machinery, antioxidative metabolism, gene expression and irreversible damage to root cells ultrastructure of CCN 51 cocoa plants, whose damage intensity depended on the exposure time to the metal. | Theobroma cacao L. | Cadmium | Heavy metal | Autophagy | Theobroma cacao L., Cadmium, Heavy metal, Autophagy | ||||||
| Chlorophyll fluorescence | Handy PEA | Planta | Zhitong Yin | National Center for Soybean Improvement | National Key Laboratory of Crop Genetics and Germplasm Enhancement | China | 2010 | Mapping quantitative trait loci associated with chlorophyll a fluorescence parameters in soybean (Glycine max (L.) Merr.) | Chlorophyll a fluorescence parameters can provide qualitative and quantitative information about photosynthetic processes in chloroplasts. JIP-test and modulated fluorescence (MF) parameters are commonly used chlorophyll a fluorescence parameters. This study was conducted to identify quantitative trait loci (QTLs) asso ciated with JIP-test parameters, MF parameters, and pho tosynthetic rate (Pn), and to examine the relationships among them in soybean (Glycine max (L.) Merr.). Pot and field experiments were performed to evaluate 184 recom binant inbred lines (RILs) for five JIP-test parameters (ABS/RC, TRq/ABS, ETo/TRq, RE(/ET0, and PIabsX four MF parameters (Fv/Fm, Fv'/Fm', <3?PSII, and qP), and PN. Significant correlations were commonly observed among JIP-test parameters, MF parameters, and PN. QTL mapping analysis identified 13, 9, and 4 QTLs for JIP-test parame ters, MF parameters, and PN, respectively, of which 13 were stable. Four major genomic regions were detected: LG A2 (19.81 cM) for JIP-test parameters, LG CI (94.31 and 97.61 cM) for PN and MF parameters, LG M (100.51 cM) for JIP-test and MF parameters, and LG O (30.61^19.91 cM) for PN, JIP-test, and MF parameters. These results indicate that chlorophyll fluorescence parameters, especially OPSII and qP, could play an important role in regulating PN, and that JIP-test and MF parameters could be controlled by the same or different genes. The QTLs identified in this study will help in the understanding of the genetic basis of photosynthetic pro cesses in plants. They will also contribute to the develop ment of marker-assisted selection breeding programs for photosynthetic capacity in soybean. | Chlorophyll a fluorescence | JIP-test | Photosynthesis | Quantitative trait loci (QTLs) | Recombinant inbred line (RIL) | Soybean | Glycine max (L.) Merr | Chlorophyll a fluorescence, JIP-test, Photosynthesis, Quantitative trait loci (QTLs), Recombinant inbred line (RIL), Soybean, Glycine max (L.) Merr | |||
| Chlorophyll fluorescence | Handy PEA | Dendrobiology | Tatiana Swoczyna | Warsaw University of Life Sciences | Department of Environmental Protection | Poland | 2010 | Photosynthetic apparatus efficiency of eight tree taxa as an indicator of their tolerance to urban environments | Urban trees, especially those growing in close proximity to roads, suffer from different kinds of stress. Most of roadside stress factors are impossible to be avoided therefore the selection of tolerant tree species andcultivars is of high importance. In our research we usedthe activity of photosystem II andchlorophyll relative content to monitor physiological state of 8 species andcultivars growing in urban environments in Warsaw. We comparedyoung trees growing 2–3 m away from the roadandothers growing minimum 8 meters away. The experiment allowed us to indicate the most tolerant taxa to roadside conditions: Gleditsia triacanthos, Pyrus calleryana ‘Chanticleer’, Platanus ×hispanica ‘Acerifolia’ and Acer campestre. We found that Quercus rubra is relatively tolerant. Tilia x europaea ‘Pallida’, Tilia cordata ‘Greenspire’ and Ginkgo biloba should not be planted in harmful habitats. | Chlorophyll a fluorescence | Performance Index | salinity stress | street environment | urban trees | Chlorophyll a fluorescence, Performance Index, salinity stress, street environment, urban trees | |||||
| Chlorophyll fluorescence | Handy PEA | Mexican Journal of Forest Sciences | Luis Manuel Morales Gallegos | Mexico | 2019 | Glucose injections in Jacaranda mimosifolia D. Don in urban areas of Texcoco de Mora | Jacaranda trees are common in urban areas of Valle de Mexico and often grows under nutritional and water stress conditions, which affects its growth. The supply of carbohydrates through the vascular system has recently been recommended as an option to improve growth and vitality. Therefore, the objective of this work is to assess the effect of glucose injected to the trunk of Jacaranda mimosifolia trees.in for concentrations: 0 (control), 30, 55 and 80 g L-1. Diameter (cm) and height (m) increments were determined, the canopy condition and foliage production were monitored and the content of carbohydrate in shoots, trunks and roots as well as the chlorophyll fluorescence (Fv/Fm). Significant differences were found (P≤0.05) in the increase in diameter and height with the application of 80 g L-1 glucose. The crown condition showed significantly higher values in density and lower in transparency, as well as an adequate foliage production, with the highest concentration (80 g L-1). Carbohydrate content showed significant differences (P≤0.05) in trunk, not in buds, roots, or chlorophyll fluorescence. The injections of glucose to the trunk have a significant effect on the growth of Jacaranda trees and affecting vitality to a lesser extent. | Urban trees | soluble sugars | chlorophyll | stress | phenology | Jacaranda mimosifolia D. Don. | Urban trees, soluble sugars, chlorophyll, stress, phenology, Jacaranda mimosifolia D. Don. | ||||||
| Chlorophyll fluorescence | Pocket PEA | Biologija | Martynas Klepeckas | Vytautas Magnus University | Lithuania | 2016 | Changes in Triticum aestivum and Hordeum vulgare chlorophyll content and fluorescence parameters under impact of various sapropel concentrations | The aim of this study was to investigate the impact of sapropel of Tarosiškis Lake on wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) photosynthesis parameters (the content of chlorophylls and chlorophyll fluorescence). Plants were sown in one-litre-volume pots by 10 seeds with light loamy soil and grown in growth chambers. Considering sapropel composition, 2.2, 3.1, and 4 t/ha dry sapropel concentrations were chosen for investigation. Sapropel-affected plants were compared with plants grown in unfertilized soils and soils fertilized with inorganic fertilizer. On day 14 of the experiment, when the plants reached the two-leaves development stage (BBCH 12), chlorophyll fluorescence parameters of the investigated plants were measured. Then the plants were grown for another four weeks and at the stem elongation stage (BBCH 31) chlorophyll fluorescence parameters were measured repeatedly, and the content of chlorophylls and carotenoids were measured as well. By increasing sapropel concentration in soil, the ratio Fv/Fm in wheat leaves increased (r = 0.97) significantly (p < 0.05) at BBCH 12 stage, but at the stem elongation stage the correlation coefficient was insignificant (r = 0.97) (p > 0.05). Fv/Fm of barley followed the same tendency. By increasing sapropel concentration, the PI index value also increased for wheat (r = 0.4; p > 0.05) and barley (r = 0.82; p < 0.05) at BBCH 12 stage, but at BBCH 31 stage it decreased. The electron transport rate increased in both wheat (r = 0.82; p < 0.05) and barley (r = 0.58; p < 0.05) at BBCH 12 stage too. With increasing sapropel concentration chlorophyll a+b content in wheat (r = 0.94) and barley (r = 0.81) increased significantly (p < 0.05), and the changes in the content of carotenoids in both plant species followed the same tendency (r = 0.87, p < 0.05). | wheat | barley | sapropel | fertilizer | photosynthesis | fluorescence | wheat, barley, sapropel, fertilizer, photosynthesis, fluorescence | |||||
| Chlorophyll fluorescence | Pocket PEA | Journal of Agronomy and Crop Science | Cristian Javier Antonelli | Universidad Nacional de San Martín | Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús | Argentina | 2018 | Physiological and anatomical traits associated with tolerance to long‐term partial submergence stress in the Lotus genus: responses of forage species, a model and an interspecific hybrid | Cattle production based on natural pastures is often subject to flooding periods, which affect plant performance and as a result, forage production. Although most forage legumes are not tolerant to flooding, Lotus spp. are outstanding alternatives, since species, such as L. tenuis (Lt) and L. corniculatus (LcT), have high forage quality and are adaptable to different environments. We recently obtained a L. tenuis × L. corniculatus hybrid (LtxLc) with potential new cultivar traits, although its tolerance to flooding stress has not yet been evaluated. In the present study, the performance of LtxLc, its parental diploid accessions, the model legume L. japonicus and tetraploid LcT were evaluated under 55 days of partial submergence stress and a 35‐day recovery period. Physiological, morphological and anatomical traits were analysed, showing that tolerance to partial submergence was positively associated with aerenchyma and adventitious root formation and relative growth rates. Overall, Lt and LtxLc showed the best responses under stress and during the recovery period. Nevertheless, the higher forage value of LtxLc makes it recommendable for use in environments affected by flooding. Our results could be used as breeding criteria for the generation of new cultivars tolerant to partial submergence stress. | aerenchyma | flooding pampa | forage | interspecific hybridization | legume | waterlogging | aerenchyma, flooding pampa, forage, interspecific hybridization, legume, waterlogging | ||||
| Chlorophyll fluorescence | Pocket PEA | Environmental and Experimental Botany | Jon Banks | The University of Reading | Department of Agriculture Policy and Development | UK | 2018 | Chlorophyll Fluorescence as a Tool to Identify Drought Stress in Acer genotypes | The effect of drought stress on continuous excitation chlorophyll fluorescence parameters and the OJIP transient is examined in cultivars of Acer campestre, A. platanoides and A. pseudoplatanus. Comparisons between whole tree level drought and desiccation of detached leaves under laboratory conditions is evaluated using both fluorescence parameters and differential kinetics. Data presented in this study suggests similarities exist between drought and desiccation. Chlorophyll fluorescence parameters which are both suitable and unsuitable at identifying drought stress are discussed and evaluated. New or uncommon fluorescence parameters and methods of analysis which may prove beneficial as drought detection tools are assessed. The over utilisation of the parameter Fv/Fm is also discussed. Results suggest utilisation of the parameters PIABS, Fo/Fm and V0(Bo) is recommended in preference to Fv/Fm, in studies aiming to identify drought stress in trees. | Acer | chlorophyll fluorescence | continuous excitation | drought | Fv/Fm | quantum efficiency | Acer, chlorophyll fluorescence, continuous excitation, drought, Fv/Fm, quantum efficiency | ||||
| Chlorophyll fluorescence | Handy PEA | Environmental and Experimental Botany | Jon Banks | The University of Reading | Department of Agriculture Policy and Development | UK | 2018 | Chlorophyll Fluorescence as a Tool to Identify Drought Stress in Acer genotypes | The effect of drought stress on continuous excitation chlorophyll fluorescence parameters and the OJIP transient is examined in cultivars of Acer campestre, A. platanoides and A. pseudoplatanus. Comparisons between whole tree level drought and desiccation of detached leaves under laboratory conditions is evaluated using both fluorescence parameters and differential kinetics. Data presented in this study suggests similarities exist between drought and desiccation. Chlorophyll fluorescence parameters which are both suitable and unsuitable at identifying drought stress are discussed and evaluated. New or uncommon fluorescence parameters and methods of analysis which may prove beneficial as drought detection tools are assessed. The over utilisation of the parameter Fv/Fm is also discussed. Results suggest utilisation of the parameters PIABS, Fo/Fm and V0(Bo) is recommended in preference to Fv/Fm, in studies aiming to identify drought stress in trees. | Acer | chlorophyll fluorescence | continuous excitation | drought | Fv/Fm | quantum efficiency | Acer, chlorophyll fluorescence, continuous excitation, drought, Fv/Fm, quantum efficiency | ||||
| Chlorophyll fluorescence | Pocket PEA | Biologia Plantarum | M. Nykiel | Warsaw University of Life Sciences | Department of Biochemistry | Poland | 2019 | Chl a fluorescence and proteomics reveal protection of the photosynthetic apparatus to dehydration in tolerant but not in susceptible wheat cultivars | Seedlings of spring wheat (Triticum aestivum L.) cultivars, Ethos and Zebra, differing in drought tolerance were dehydrated to reach a water saturation deficit (WSD) in leaves ~15, 30, and 50 %. Ethos, the drought tolerant cultivar, dried slower in comparison with Zebra and regrew in 70 % upon rehydration. The effect of dehydration on photosystem II was evaluated by Chl a fluorescence (OJIP transients). The inflection point of double normalized curves (ΔWOJ) calculated for Ethos was negative for seedlings with 15 % WSD, nearly zero for those with 30 % WSD, and about +0.05 for those with 50 % WSD. In case of Zebra, the 15 % WSD already induced a positive ΔWOJ (+0.05) and 50 % WSD maximized it to +0.10, which is a sign of drought susceptibility. The proteomic studies revealed, that among identified 850 spots, 80 protein spots were differentially expressed during dehydration. The differentially expressed proteins of the drought tolerant cultivar indicated the protection of the photosynthetic apparatus and proteome rebuilding in response to drought. In the drought susceptible cultivar, protection of proteins and membranes and partial scavenging reactive oxygen species appeared. | 2D electrophoresis | drought | Kautsky effect | OJIP | polyphasic fluorescence transient | Triticum aestivum | 2D electrophoresis, drought, Kautsky effect, OJIP, polyphasic fluorescence transient, Triticum aestivum | ||||
| Chlorophyll fluorescence | Pocket PEA | Journal of Plant Physiology | María Paula Campestre | Unidad de Biotecnología | Instituto de Investigaciones Biotecnológicas - Instituto Tecnológico Chascomús | Argentina | 2016 | Lotus japonicus plants of the Gifu B-129 ecotype subjected to alkaline stress improve their Fe2+ bio-availability through inoculation with Pantoea eucalypti M91 | Inoculation assays with Pantoea eucalypti M91 were performed on Lotus japonicus ecotype Gifu. Under alkaline conditions, this ecotype is characterized by the development of interveinal chlorosis of the apical leaves due to low mobilization of Fe2+. Inoculation with P. eucalypti M91, a plant growth-promoting bacterial strain capable of producing pyoverdine-like and pyochelin-like siderophores under alkaline growth conditions, alters the root, resulting in a herringbone pattern of root branching. Additional features include improvement in Fe2+ transport to the shoots, acidification of the hydroponic solution of the plant cultures, and an accompanying increase in the efficiency of the PSII parameters. In addition, there was an increase in the expression of the FRO1 and IRT1 genes, accompanied by a significant increase in FRO activity. Results showed that P. eucalypti M91 has a beneficial effect on the Fe acquisition machinery of Strategy I, as described for non-graminaceous monocots and dicots, suggesting its potential as an inoculant for legume crops cultivated in alkaline soils. | Lotus japonicus | Alkaline soils | Fe deficiency | Pantoea sp. | PGPB | Lotus japonicus, Alkaline soils, Fe deficiency, Pantoea sp., PGPB | |||||
| Chlorophyll fluorescence | Pocket PEA | Plant Physiology and Biochemistry | Mariana L. Checovich | Universidad Nacional de San Martín | Instituto Tecnológico Chascomús | Argentina | 2016 | The stay-green phenotype of TaNAM-RNAi wheat plants is associated with maintenance of chloroplast structure and high enzymatic antioxidant activity | TaNAM transcription factors play an important role in controlling senescence, which in turn, influences the delivery of nitrogen, iron and other elements to the grain of wheat (Triticum aestivum) plants, thus contributing to grain nutritional value. While lack or diminished expression of TaNAMs determines a stay-green phenotype, the precise effect of these factors on chloroplast structure has not been studied. In this work we focused on the events undergone by chloroplasts in two wheat lines having either control or diminished TaNAM expression due to RNA interference (RNAi). It was found that in RNAi plants maintenance of chlorophyll levels and maximal photochemical efficiency of photosystem II were associated with lack of chloroplast dismantling. Flow cytometer studies and electron microscope analysis showed that RNAi plants conserved organelle ultrastructure and complexity. It was also found that senescence in control plants was accompanied by a low leaf enzymatic antioxidant activity. Lack of chloroplast dismantling in RNAi plants was associated with maintenance of protein and iron concentration in the flag leaf, the opposite being observed in control plants. These data provide a structural basis for the observation that down regulation of TaNAMs confers a functional stay-green phenotype and indicate that the low export of iron and nitrogen from the flag leaf of these plants is concomitant, within the developmental window studied, with lack of chloroplast degradation and high enzymatic antioxidant activity. | Chloroplast | NAM | Senescence | Stay-green | Triticum aestivum | Wheat | Chloroplast, NAM, Senescence, Stay-green, Triticum aestivum, Wheat | ||||
| Chlorophyll fluorescence | Pocket PEA | Water SA | Tendai Polite Chibarabada | University of KwaZulu-Natal | School of Agricultural, Earth and Environmental Sciences | South Africa | 2015 | Water use characteristics of a bambara groundnut (Vigna subterranea L. Verdc) landrace during seedling establishment | Bambara groundnut is slow to establish and this has negative implications for total water use. Consideration of bambara groundnut as a water-efficient crop for dry areas will benefit from an understanding of water use efficiency and water use characteristics during establishment. We investigated whether there is an association between seed-coat colour of bambara groundnut seeds and water use efficiency. A secondary objective was to determine physiological and metabolic responses of bambara groundnut to terminal water stress during seedling establishment. Bambara groundnut seedlings showed reduced seedling canopy growth, increased root length and root: shoot ratio, as well as increased total soluble sugars and tissue water potential with decreasing water availability – traits associated with drought avoidance mechanisms. Consequently, seedling water use efficiency improved with decreasing water availability. Acclimation to water stress was observed under terminal stress; previously stressed seedlings responded better than previously non-stressed seedlings. Dark-coloured seeds had higher levels of phenolics which may have led to their enhanced performance during seedling emergence as well as improved drought tolerance and seedling WUE. | drought | physiological | metabolic | growth | water use efficiency | drought, physiological, metabolic, growth, water use efficiency | |||||
| Chlorophyll fluorescence | Handy PEA | Advances in Environmental Biology | Hamid R. Roosta | Vali-e-Asr University of Rafsanjan | Dept. of Horticulture | Iran | 2012 | Effects Of Different Cultivation Media On Vegetative Growth, Ecophysiological Traits And Nutrients Concentration In Strawberry Under Hydroponic And Aquaponic Cultivation Systems | Aquaponics is the science of integrating the production of fish and plants in a symbiotic environment in which fish waste is used as fertilizer. The characteristics of the materials used as substrate in soilless culture systems, directly and indirectly affect the plant growth and production. Therefore, in order to study the effect of different substrates (various ratios of perlite and cocopeat) on growth and development of strawberry in hydroponic and aquaponic cultivation systems, a greenhouse experiment was conducted as factorial experiment based on a completely randomized design with three replications. The results of statistical analysis revealed that dry weight (leaf, crown and root), the number of runners, leaf area, SPAD index for old leaves, Fv/Fm, the concentrations of N, K, P, Fe and Mg in leaves and the yield was significantly higher in hydroponic than in aquaponic (except for the substrate of sole perlite). The concentrations of Ca, Zn (except for the substrate of sole cocopeat) and Mn (except for the substrates of sole perlite or cocopeat) in leaves and SPAD index of young leaves were higher in aquaponic than in hydroponic. The remaining measured traits were not affected by the culture system. In hydroponic system, the substrates of sole perlite or cocopeat were not recognized as optimum substrates; therefore, it is recommended to use their mixture as substrate, while in aquaponic system, the substrates with higher percentage of perlite had better performance and are recommended for strawberry cultivation. | aquaponics | substrate | strawberry | soilless culture | aquaponics, substrate, strawberry, soilless culture | ||||||
| Chlorophyll fluorescence | Pocket PEA | MDPI: Forests | Latifa Al Kharusi | Sultan Qaboos University | Department of Biology | Oman | 2017 | Screening of Date Palm (Phoenix dactylifera L.) Cultivars for Salinity Tolerance | Date palm (Phoenix dactylifera L.) is a major fruit tree in the Middle East and it is a plant considered to be tolerant to a variety of abiotic stresses, including salinity. However, the physiological basis of its salinity tolerance is not fully known. The objective of this study was to screen Omani date palm cultivars for tolerance or susceptibility to salt stress. Seedlings from 10 commercially important date palm cultivars were subjected to 240 mM NaCl, and several physiological parameters related to salinity tolerance traits were evaluated upon treatment. The cultivars were divided into two groups based on the dry weight (DW) of their leaf and root tissues, a parameter which was used as an indication of healthy growth. The results revealed that photosynthesis, electrolyte leakage (EL), and the shoot K+/Na+ ratio were all significantly reduced in the susceptible cultivars. In addition, the relative water content was higher in the tolerant cultivars in comparison with the susceptible ones. These results suggest that although date palm is tolerant to high salinity, there is variation in tolerance among different cultivars. Shoot Na+ exclusion, photosynthesis, and membrane stability are apparently the main determinants of tolerance and can be used in salinity tolerance screening of date palm. The results have shown new very tolerant cultivars (Manoma and Umsila) that could serve as genetic resources for improved date palm tolerance to salinity. | date palm | salt stress | screening | tolerance | susceptible | photosynthesis | sodium | potassium | date palm, salt stress, screening, tolerance, susceptible, photosynthesis, sodium, potassium | ||
| Chlorophyll fluorescence | Pocket PEA | Frontiers in Plant Science | Ellen E. Pflug | Swiss Federal Institute for Forest, Snow and Landscape Research | Forest Dynamics | Switzerland | 2018 | Resilient Leaf Physiological Response of European Beech (Fagus sylvatica L.) to Summer Drought and Drought Release | Drought is a major environmental constraint to trees, causing severe stress and thus adversely affecting their functional integrity. European beech (Fagus sylvatica L.) is a key species in mesic forests that is commonly expected to suffer in a future climate with more intense and frequent droughts. Here, we assessed the seasonal response of leaf physiological characteristics of beech saplings to drought and drought release to investigate their potential to recover from the imposed stress and overcome previous limitations. Saplings were transplanted to model ecosystems and exposed to a simulated summer drought. Pre-dawn water potentials (%pd), stomatal conductance (gS), intercellular CO2 concentration (ci), net-photosynthesis (AN), PSII chlorophyll fluorescence (PItot), non-structural carbohydrate concentrations (NSC; soluble sugars, starch) and carbon isotope signatures were measured in leaves throughout the growing season. Pre-dawn water potentials (%pd), gS, ci, AN, and PItot decreased as drought progressed, and the concentration of soluble sugars increased at the expense of starch. Carbon isotopes in soluble sugars (d13CS) showed a distinct increase under drought, suggesting, together with decreased ci, stomatal limitation of AN. Drought effects on %pd, ci, and NSC disappeared shortly after re-watering, while full recovery of gS, AN, and PItot was delayed by 1 week. The fast recovery of NSC was reflected by a rapid decay of the drought signal in d13C values, indicating a rapid turnover of assimilates and a reactivation of carbon metabolism. After recovery, the previously drought-exposed saplings showed a stimulation of AN and a trend toward elevated starch concentrations, which counteracted the previous drought limitations. Overall, our results suggest that the internal water relations of beech saplings and the physiological activity of leaves are restored rapidly after drought release. In the case of AN, stimulation after drought may partially compensate for limitations on photosynthetic activity during drought. Our observations suggest high resilience of beech to drought, contradicting the general belief that beech is particularly sensitive to environmental stressors. | non-structural carbohydrates | photosynthesis | recovery | water shortage | non-structural carbohydrates, photosynthesis, recovery, water shortage | ||||||
| Chlorophyll content | CL-01 | Frontiers in Plant Science | Tadeo F. Fernandez-Göbel | Instituto Nacional de Tecnología Agropecuaria | Instituto de Fisiología y Recursos Genéticos Vegetales | Argentina | 2019 | Redox Systemic Signaling and Induced Tolerance Responses During Soybean–Bradyrhizobium japonicum Interaction: Involvement of Nod Factor Receptor and Autoregulation of Nodulation | The symbiotic relationship between legumes and nitrogen-fixing rhizobia induces local and systemic responses, which ultimately lead to nodule formation. The autoregulation of nodulation (AON) is a systemic mechanism related to innate immunity that controls nodule development and involves different components ranging from hormones, peptides, receptors to small RNAs. Here, we characterized a rapid systemic redox changes induced during soybean–Bradyrhizobium japonicum symbiotic interaction. A transient peak of reactive oxygen species (ROS) generation was found in soybean leaves after 30 min of root inoculation with B. japonicum. The ROS response was accompanied by changes in the redox state of glutathione and by activation of antioxidant enzymes. Moreover, the ROS peak and antioxidant enzyme activation were abolished in leaves by the addition, in either root or leaf, of DPI, an NADPH oxidase inhibitor. Likewise, these systemic redox changes primed the plant increasing its tolerance to photooxidative stress. With the use of non-nodulating nfr5-mutant and hyper-nodulating nark-mutant soybean plants, we subsequently studied the systemic redox changes. The nfr5-mutant lacked the systemic redox changes after inoculation, whereas the nark-mutant showed a similar redox systemic signaling than the wild type plants. However, neither nfr5- nor nark-mutant exhibited tolerance to photooxidative stress condition. Altogether, these results demonstrated that (i) the early redox systemic signaling during symbiotic interaction depends on a Nod factor receptor, and that (ii) the induced tolerance response depends on the AON mechanisms. | systemic changes | redox signaling | rhizobia | soybean symbiosis | ISR/PGPR-like response | autoregulation of nodulation | systemic changes, redox signaling, rhizobia, soybean symbiosis, ISR/PGPR-like response, autoregulation of nodulation | ||||
| Chlorophyll fluorescence | FMS 2 | Frontiers in Plant Science | Tadeo F. Fernandez-Göbel | Instituto Nacional de Tecnología Agropecuaria | Instituto de Fisiología y Recursos Genéticos Vegetales | Argentina | 2019 | Redox Systemic Signaling and Induced Tolerance Responses During Soybean–Bradyrhizobium japonicum Interaction: Involvement of Nod Factor Receptor and Autoregulation of Nodulation | The symbiotic relationship between legumes and nitrogen-fixing rhizobia induces local and systemic responses, which ultimately lead to nodule formation. The autoregulation of nodulation (AON) is a systemic mechanism related to innate immunity that controls nodule development and involves different components ranging from hormones, peptides, receptors to small RNAs. Here, we characterized a rapid systemic redox changes induced during soybean–Bradyrhizobium japonicum symbiotic interaction. A transient peak of reactive oxygen species (ROS) generation was found in soybean leaves after 30 min of root inoculation with B. japonicum. The ROS response was accompanied by changes in the redox state of glutathione and by activation of antioxidant enzymes. Moreover, the ROS peak and antioxidant enzyme activation were abolished in leaves by the addition, in either root or leaf, of DPI, an NADPH oxidase inhibitor. Likewise, these systemic redox changes primed the plant increasing its tolerance to photooxidative stress. With the use of non-nodulating nfr5-mutant and hyper-nodulating nark-mutant soybean plants, we subsequently studied the systemic redox changes. The nfr5-mutant lacked the systemic redox changes after inoculation, whereas the nark-mutant showed a similar redox systemic signaling than the wild type plants. However, neither nfr5- nor nark-mutant exhibited tolerance to photooxidative stress condition. Altogether, these results demonstrated that (i) the early redox systemic signaling during symbiotic interaction depends on a Nod factor receptor, and that (ii) the induced tolerance response depends on the AON mechanisms. | systemic changes | redox signaling | rhizobia | soybean symbiosis | ISR/PGPR-like response | autoregulation of nodulation | systemic changes, redox signaling, rhizobia, soybean symbiosis, ISR/PGPR-like response, autoregulation of nodulation | ||||
| Chlorophyll fluorescence | Pocket PEA | Frontiers in Plant Science | Tadeo F. Fernandez-Göbel | Instituto Nacional de Tecnología Agropecuaria | Instituto de Fisiología y Recursos Genéticos Vegetales | Argentina | 2019 | Redox Systemic Signaling and Induced Tolerance Responses During Soybean–Bradyrhizobium japonicum Interaction: Involvement of Nod Factor Receptor and Autoregulation of Nodulation | The symbiotic relationship between legumes and nitrogen-fixing rhizobia induces local and systemic responses, which ultimately lead to nodule formation. The autoregulation of nodulation (AON) is a systemic mechanism related to innate immunity that controls nodule development and involves different components ranging from hormones, peptides, receptors to small RNAs. Here, we characterized a rapid systemic redox changes induced during soybean–Bradyrhizobium japonicum symbiotic interaction. A transient peak of reactive oxygen species (ROS) generation was found in soybean leaves after 30 min of root inoculation with B. japonicum. The ROS response was accompanied by changes in the redox state of glutathione and by activation of antioxidant enzymes. Moreover, the ROS peak and antioxidant enzyme activation were abolished in leaves by the addition, in either root or leaf, of DPI, an NADPH oxidase inhibitor. Likewise, these systemic redox changes primed the plant increasing its tolerance to photooxidative stress. With the use of non-nodulating nfr5-mutant and hyper-nodulating nark-mutant soybean plants, we subsequently studied the systemic redox changes. The nfr5-mutant lacked the systemic redox changes after inoculation, whereas the nark-mutant showed a similar redox systemic signaling than the wild type plants. However, neither nfr5- nor nark-mutant exhibited tolerance to photooxidative stress condition. Altogether, these results demonstrated that (i) the early redox systemic signaling during symbiotic interaction depends on a Nod factor receptor, and that (ii) the induced tolerance response depends on the AON mechanisms. | systemic changes | redox signaling | rhizobia | soybean symbiosis | ISR/PGPR-like response | autoregulation of nodulation | systemic changes, redox signaling, rhizobia, soybean symbiosis, ISR/PGPR-like response, autoregulation of nodulation | ||||
| Chlorophyll fluorescence | Pocket PEA | Journal of Agronomy and Crop Science | A. Gazquez | Unidad de Biotecnolog ıa | Laboratorio de Fisiolog ıa de Estr es Abi otico en Plantas | Argentina | 2014 | Physiological Response of Multiple Contrasting Rice (Oryza sativa L.) Cultivars to Suboptimal Temperatures | The physiological response of multiple rice cultivars, eighteen initially and eight cultivars later on, to suboptimal temperatures (ST) conditions was investigated in laboratory and outdoor experimental conditions. Treatment with ST decreased growth in different extents according to the cultivar and affected the PSII performance, determined by chlorophyll fluorescence fast-transient test, and stomatal conductance, regardless the experimental condition. Two groups of cultivars could be distinguished on the base of their growth and physiological parameters. The group of cultivars presenting higher growths displayed optimal JIP values, and higher instantaneous water use efficiency (WUEi), due to a lower Gs under ST, unlike cultivars showing lower growth values, which presented worse JIP values and could not adjust their Gs and hence their WUEi. In this work, we detected at least two cultivars with superior tolerance to ST than the cold tolerant referent Koshihikari. These cultivars could be used as parents or tolerance donors in breeding for new crop varieties. On other hand, positive and significant correlations between data obtained from laboratory and outdoor experiments suggest that laboratory measurements of most of the above mentioned parameters would be useful to predict the response of rice cultivars to ST outdoor. | instantaneous water use efficiency | JIP test | net photosynthesis rate | Oryza sativa | stomatal conductance | suboptimal temperatures | instantaneous water use efficiency, JIP test, net photosynthesis rate, Oryza sativa, stomatal conductance, suboptimal temperatures | ||||
| Chlorophyll fluorescence | Pocket PEA | Plant Physiology and Biochemistry | Mayank Anand Gururani | Konkuk University | Dept. of Molecular Biotechnology | South Korea | 2012 | Physiological and biochemical responses of transgenic potato plants with altered expression of PSII manganese stabilizing protein | Manganese-stabilizing protein (MSP) represents a key component of the oxygen-evolving complex (OEC). Transgenic potato plants with both enhanced (sense) and reduced (anti-sense) MSP expression levels were generated to investigate the possible physiological role of MSP in overall plant growth, particularly in tuber development. MSP antisense plants exhibited both higher tuberization frequency and higher tuber yield with increased total soluble carbohydrates. The photosynthetic efficiencies of the plants were examined using the OJIP kinetics; MSP-antisense plants were photosynthetically more active than the MSP-sense and UT (untransformed) control plants. The oxygen measurements indicated that the relative oxygen evolution was directly proportional to the MSP expression, as MSP-antisense plants showed much lower oxygen evolution compared to MSP-sense as well as UT plants. MSP-sense plants behaved like the UT plants with respect to morphology, tuber yield, and photosynthetic performance. Chlorophyll a fluorescence analyses indicate a possible lack of intact Oxygen Evolving Complexes (OECs) in MSP antisense plants, which allow access to internal non-water electron donors (e.g., ascorbate and proline) and consequently increase the Photosystem II (PSII) activity of those plants. These findings further indicate that this altered photosynthetic machinery may be associated with early tuberization and increased tuberization frequency. | Oxygen evolving complex | Photosystem II | Solanum tuberosum | Oxygen evolving complex, Photosystem II, Solanum tuberosum | |||||||
| Oxygen electrode | S1 | Plant Physiology and Biochemistry | Mayank Anand Gururani | Konkuk University | Dept. of Molecular Biotechnology | South Korea | 2012 | Physiological and biochemical responses of transgenic potato plants with altered expression of PSII manganese stabilizing protein | Manganese-stabilizing protein (MSP) represents a key component of the oxygen-evolving complex (OEC). Transgenic potato plants with both enhanced (sense) and reduced (anti-sense) MSP expression levels were generated to investigate the possible physiological role of MSP in overall plant growth, particularly in tuber development. MSP antisense plants exhibited both higher tuberization frequency and higher tuber yield with increased total soluble carbohydrates. The photosynthetic efficiencies of the plants were examined using the OJIP kinetics; MSP-antisense plants were photosynthetically more active than the MSP-sense and UT (untransformed) control plants. The oxygen measurements indicated that the relative oxygen evolution was directly proportional to the MSP expression, as MSP-antisense plants showed much lower oxygen evolution compared to MSP-sense as well as UT plants. MSP-sense plants behaved like the UT plants with respect to morphology, tuber yield, and photosynthetic performance. Chlorophyll a fluorescence analyses indicate a possible lack of intact Oxygen Evolving Complexes (OECs) in MSP antisense plants, which allow access to internal non-water electron donors (e.g., ascorbate and proline) and consequently increase the Photosystem II (PSII) activity of those plants. These findings further indicate that this altered photosynthetic machinery may be associated with early tuberization and increased tuberization frequency. | Oxygen evolving complex | Photosystem II | Solanum tuberosum | Oxygen evolving complex, Photosystem II, Solanum tuberosum | |||||||
| Chlorophyll fluorescence | M-PEA | Plant Physiology and Biochemistry | Mayank Anand Gururani | Konkuk University | Dept. of Molecular Biotechnology | South Korea | 2012 | Physiological and biochemical responses of transgenic potato plants with altered expression of PSII manganese stabilizing protein | Manganese-stabilizing protein (MSP) represents a key component of the oxygen-evolving complex (OEC). Transgenic potato plants with both enhanced (sense) and reduced (anti-sense) MSP expression levels were generated to investigate the possible physiological role of MSP in overall plant growth, particularly in tuber development. MSP antisense plants exhibited both higher tuberization frequency and higher tuber yield with increased total soluble carbohydrates. The photosynthetic efficiencies of the plants were examined using the OJIP kinetics; MSP-antisense plants were photosynthetically more active than the MSP-sense and UT (untransformed) control plants. The oxygen measurements indicated that the relative oxygen evolution was directly proportional to the MSP expression, as MSP-antisense plants showed much lower oxygen evolution compared to MSP-sense as well as UT plants. MSP-sense plants behaved like the UT plants with respect to morphology, tuber yield, and photosynthetic performance. Chlorophyll a fluorescence analyses indicate a possible lack of intact Oxygen Evolving Complexes (OECs) in MSP antisense plants, which allow access to internal non-water electron donors (e.g., ascorbate and proline) and consequently increase the Photosystem II (PSII) activity of those plants. These findings further indicate that this altered photosynthetic machinery may be associated with early tuberization and increased tuberization frequency. | Oxygen evolving complex | Photosystem II | Solanum tuberosum | Oxygen evolving complex, Photosystem II, Solanum tuberosum | |||||||
| Chlorophyll fluorescence | Pocket PEA | Photosynthetica | S.R. HOSSEINZADEH | Lorestan University | Department of Biology | Iran | 2015 | Effect of vermicompost fertilizer on photosynthetic characteristics of chickpea (Cicer arietinum L.) under drought stress | Water availability is an important factor for plant growth in arid environments. In recent decades, vermicompost (VC) fertilizer has been used in agriculture as a safe and effective fertilizer with high water-holding capacity. The aim of the present study was to characterize effects of VC fertilizer on photosynthetic activity of chickpea (Cicer arietinum L. cv. karaj) under drought conditions at three growth stages. Tests were done at five volumetric ratios of vermicompost to soil: 0:100, 10:90, 20:80, and 30:70; and three levels of drought stress; non-stress (NS), moderate drought stress (MS), and severe drought stress (SS) (100, 75, and 25% of field capacity, respectively). Evaluations were made for chlorophyll content, gas exchange, and chlorophyll fluorescence at different growth stages: a seedling, flowering, and podding stage. Results demonstrated that VC treatment under NS conditions significantly increased total chlorophyll content [Chl (a+b)], intercellular CO2 concentration (Ci), net photosynthetic rate (PN), transpiration rate (E), and maximal quantum yield of PSII photochemistry (Fv/Fm) at all three stages. The VC addition at 10 and 20% significantly enhanced Chl content and Fv/Fm under MS and Fv/Fm, Ci, and PN under SS at the flowering stage. In conclusion, the above results showed that VC fertilizer had a positive effect on photosynthesis of chickpea under NS conditions, but no positive effect was found under MS and SS. | chlorophyll | gas exchange | organic fertilizer | water stress | chlorophyll, gas exchange, organic fertilizer, water stress | ||||||
| Chlorophyll fluorescence | Handy PEA | International Geoscience and Remote Sensing Symposium | Yanbo Huang | USDA-Agricultural Research Service | Crop Production Systems Research Unit | USA | 2017 | Detection Of Crop Herbicide Injury Through Plant Hyperspectral Remote Sensing Of Chlorophyll Fluorescence | Crop injury from off-target herbicide application is of primary concern to farmers. Timely determination of crop injury is critical for farmers to take appropriate actions for remediation before it is too late. Traditionally, crop injury was determined by field sampling and measuring plant biological responses, making it difficult to provide timely information. We conducted studies to evaluate optical remote sensing techniques to detect the onset of herbicide crop injury. The techniques included measuring plant hyperspectral reflectance, PROSPECT model-based biological parameter sensitivity analysis, and biological parameter inversion, and measuring plant chlorophyll florescence. In our studies, we focused on the effect of glyphosate, a non-selective, systemic herbicide, highly toxic to sensitive plant species. It has been the most widely used herbicide and its use has seen a significant increase due to the increased utilization of genetically modified glyphosateresistant crops in the last two decades. The data analysis indicated that the results using different techniques are varied but they basically outperform the method of vegetation indices directly derived from the remotely sensed data. | early detection | crop injury | glyphosate | hyperspectral | chlorophyll fluorescence | early detection, crop injury, glyphosate, hyperspectral, chlorophyll fluorescence | |||||
| Chlorophyll fluorescence | Handy PEA | Photochemistry Research Progress | Hazem M. Kalaji | Warsaw Agricultural University | Department of Plant Physiology | Poland | 2008 | Chlorophyll Fluorescence: A Useful Tool In Barley Plant Breeding Programs | Plant growth and development are dynamic processes which are continuously changed by environmental conditions. Nowadays, with the availability of performance instruments, many physiological parameters, which correlate with plant growth, development and economic yield under biotic and abiotic stresses, are exploited as indicators in plant breeding programs. Chlorophyll a fluorescence is a fast, non-invasive, non-destructive and informative tool to study physiological state of photosynthetic apparatus of any photosynthesizing material. It gives the ability to analyze the individual life processes and to develop an understanding of the plant’s response to fluctuations in environmental conditions. In this paper, we discuss responses of photosynthetic apparatus of barley plants growing under various abiotic stresses: high and low temperature, high and low light, salinity, heavy metals, nutrient deficiencies and drought. Beside measurement of basic fluorescence chlorophyll, quantitative analysis of the fluorescence transient (JIPtest) are discussed. This test helps to explain the stepwise flow of energy through PSII: absorption, trapping and electron transport. This sort of analysis enables to understand the relationships between the biophysical side of photosynthesis, signals of the fluorescence and its analytical expressions. The results show the differentiation in extracted and technical fluorescence parameters, quantum efficiencies, specific and phenomenological fluxes of barely plant growing under unfavorable growth conditions. This work approves that chlorophyll fluorescence is one of vital tools to monitor PSII reaction to different abiotic stresses. Moreover, it allows distinguishing stress type that plant experience in certain environmental growth conditions. Different chlorophyll fluorescence parameters are discussed and proposed to be used as trustworthy indicators in selection for abiotic stresses tolerance in barely germplasm. | |||||||||||
| Chlorophyll fluorescence | Pocket PEA | MDPI: Minerals | Maja Radziemska | Warsaw University of Life Sciences | Institute of Environmental Engineering | Poland | 2020 | Immobilization of Potentially Toxic Elements (PTE) by Mineral-Based Amendments: Remediation of Contaminated Soils in Post-Industrial Sites | In many post-industrial sites, the high contents and high mobility of di erent potentially toxic elements (PTEs) make the soils unsuitable for e ective management and use. Therefore, immobilization of PTE seems to be the best remediation option for such areas. In the present study, soil samples were collected in post-industrial areas in Northeastern Poland. The analyzed soil was characterized by especially high contents of Cd (22 mg kg-1), Pb (13 540 mg kg-1), and Zn (8433 mg kg-1). Yellow lupine (Lupinus luteus L.) and two types of mineral-based amendments were used to determine their combined remediation e ect on PTE immobilization. A greenhouse pot experiment was conducted to evaluate the influence of chalcedonite and halloysite on plant growth, chlorophyll a fluorescence, the leaf greenness index (SPAD), PTE uptake, and the physicochemical properties and toxicity of soil. The application of chalcedonite resulted in the greatest increase in soil pH, whereas halloysite contributed to the greatest reduction in the contents of Ni, Pb, Zn, and Cr in soil, compared with the control treatment. The addition of halloysite significantly increased plant biomass. The application of mineral-based amendments increased the ratio of variable fluorescence to maximum chlorophyll fluorescence (Fv/Fm) in yellow lupine leaves. The leaf greenness index was highest in plants growing in soil amended with chalcedonite. The results of this study suggest that mineral-based amendments combined with yellow lupine could potentially be used for aided phytostabilization of multi-PTE contaminated soil in a post-industrial area. | soil amendments | immobilization | halloysite | chalcedonite | soil amendments, immobilization, halloysite, chalcedonite | ||||||
| Chlorophyll fluorescence | Handy PEA | MDPI: Minerals | Maja Radziemska | Warsaw University of Life Sciences | Institute of Environmental Engineering | Poland | 2020 | Immobilization of Potentially Toxic Elements (PTE) by Mineral-Based Amendments: Remediation of Contaminated Soils in Post-Industrial Sites | In many post-industrial sites, the high contents and high mobility of di erent potentially toxic elements (PTEs) make the soils unsuitable for e ective management and use. Therefore, immobilization of PTE seems to be the best remediation option for such areas. In the present study, soil samples were collected in post-industrial areas in Northeastern Poland. The analyzed soil was characterized by especially high contents of Cd (22 mg kg-1), Pb (13 540 mg kg-1), and Zn (8433 mg kg-1). Yellow lupine (Lupinus luteus L.) and two types of mineral-based amendments were used to determine their combined remediation e ect on PTE immobilization. A greenhouse pot experiment was conducted to evaluate the influence of chalcedonite and halloysite on plant growth, chlorophyll a fluorescence, the leaf greenness index (SPAD), PTE uptake, and the physicochemical properties and toxicity of soil. The application of chalcedonite resulted in the greatest increase in soil pH, whereas halloysite contributed to the greatest reduction in the contents of Ni, Pb, Zn, and Cr in soil, compared with the control treatment. The addition of halloysite significantly increased plant biomass. The application of mineral-based amendments increased the ratio of variable fluorescence to maximum chlorophyll fluorescence (Fv/Fm) in yellow lupine leaves. The leaf greenness index was highest in plants growing in soil amended with chalcedonite. The results of this study suggest that mineral-based amendments combined with yellow lupine could potentially be used for aided phytostabilization of multi-PTE contaminated soil in a post-industrial area. | soil amendments | immobilization | halloysite | chalcedonite | soil amendments, immobilization, halloysite, chalcedonite | ||||||
| Chlorophyll fluorescence | Pocket PEA | Proc. 7th International Postharvest Symposium | S.H. Mirdehghan | Vali-e-Asr University of Rafsanjan | Department of Horticultural Sciences | Iran | 2013 | Avoiding the Paleness of Pomegranate Arils by Preharvest Application of Salicylic Acid and Potassium Sulfate | The physiological disorder of aril paleness, thought to occur due to oxidative stress, in pomegranate threatens the popularity of this fruit. Based on the results of a preliminary experiment on pomegranate trees, a factorial experiment was designed consisting of salicylic acid (0, 0.3 and 0.6 mM) and potassium sulfate (0, 0.5 and 1%). The prepared concentrations of above mentioned treatments were foliar sprayed to the trees 9 and 13 weeks after full bloom. Results showed that these compounds could alleviate the aril paleness of fruit, manifested by higher chroma values of arils and peel of pomegranate and maintain the overall quality of fruit compared to the control. In addition, total phenolics and antioxidant activity increased in fruit of treated tree by potassium sulfate at harvest while the lowest values of these parameters were observed in the control. The result of measuring photosynthetic parameters and pigments showed that treated plants have higher Fv/Fm, pi and some pigment of plants compared to the control. Thus preharvest treatments with salicylic acid and potassium sulfate could be considered as suitable tools to avoid paleness of pomegranate arils with higher bioactive compounds and antioxidant activity as compared to control fruit. | anthocyanin | antioxidant activity | phenolic compounds | Fv/Fm | anthocyanin, antioxidant activity, phenolic compounds, Fv/Fm | ||||||
| Chlorophyll fluorescence | Pocket PEA | Proc. Vth International Conference Postharvest Unlimited | M. Mirzaee | University of Greenwich | Department of Food and Marketing | UK | 2015 | Diagnosing Bitter Pit in Apple during Storage by Chlorophyll Fluorescence as a Non-Destructive Tool | Bitter pit is an important physiological disorder of apple that can develop on the tree but is most prevalent during storage. Delaying fruit maturation after harvest through controlled atmosphere storage and application of 1-MCP (SmartFreshTM) can delay the onset of symptoms; however, significant losses may occur in long-term stored apples. It is hard to detect internal bitter pit using external examination alone. Current predictive methods are based on destructive internal quality assessments and mineral analysis. A non-destructive method to detect and predict the propensity of fruit to develop bitter pit at harvest and during the early stages of storage would improve store management practices. High risk ‘Bramley’ orchards were identified from over 100 orchards surveyed across the south east of UK in 2010/11. A subsample of susceptible orchards with fruit that consistently developed bitter pit in storage as well as orchards where fruit remained free from problems were selected. Trials were conducted over two consecutive seasons (2012/13 and 2013/14) to evaluate changes of chlorophyll fluorescence in SmartFreshTM treated and untreated ‘Bramley’ apples during storage. The relationship between chlorophyll fluorescence profiles and bitter pit incidence were similar in the presence or absence of SmartFreshTM. In the early stages of storage, the chlorophyll fluorescence profiles were able to distinguish between SmartFreshTM treated and untreated samples and correlated well with fruit maturity, rate of ethylene production and onset of bitter pit; however, they were less discriminatory in determining the severity of bitter pit in long-term storage. The most discriminant chlorophyll fluorescence characteristics correlated to bitter pit were identified. Models have been developed to predict the likely incidence and development of bitter pit during storage, although they are not capable of estimating severity of the disorder. | ‘Bramley’s Seedling’ apple | CA storage | 1-MCP | bitter pit | chlorophyll fluorescence characteristics | ‘Bramley’s Seedling’ apple, CA storage, 1-MCP, bitter pit, chlorophyll fluorescence characteristics | |||||
| Chlorophyll fluorescence | Pocket PEA | Photosynthetica | Y. MOHSENIAN | University of Rafsanjan | Department of Horticulture | Iran | 2012 | Investigation of the ameliorating effects of eggplant, datura, orange nightshade, local Iranian tobacco, and field tomato as rootstocks on alkali stress in tomato plants | Among the most important quality parameters of irrigation water used for greenhouse crops, alkalinity of water is considered critical due to its impact on soil or growing medium solution pH. In this study, plant growth, Fe content, photosynthetic pigment content, maximal quantum yield of PSII photochemistry (Fv/Fm), performance index (PI), leaf relative water content (LRWC), and soluble sugars concentration were investigated in nongrafted and grafted tomato (Lycopersicon esculentum Mill. cv. Red stone) plants onto five rootstocks of eggplant (Solanum melongena cv. Long purple), datura (Datura patula), orange nightshade (Solanum luteum Mill.), local Iranian tobacco (Nicotiana tabacum), and field tomato (Lycopersicon esculentum Mill. cv. Cal.jn3), exposed to 0, 5, and 10 mM NaHCO3 concentrations, to determine whether grafting could improve alkalinity tolerance of tomato. Significant depression of leaf area, leaf and stem dry mass, shoot and root Fe content and LRWC under high NaHCO3 level was observed in both grafted and ungrafted plants. The highest reduction in the shoot Fe content was observed at 10 mM sodium bicarbonate in control plants (greenhouse tomato). Moreover, at high HCO3 – level, the highest percentage of LRWC reduction was also recorded in ungrafted plants. Values of Fv/Fm and PI decreased significantly at 5 and 10 mM NaHCO3 irrespective of rootstock type. The present study revealed that soluble sugars content, photosynthetic pigments content, Fv/Fm and PI values in plants grafted onto datura rootstock were higher than those in nongrafted and rest of the grafted plants. Thus, the use of datura rootstock could provide a useful tool to improve alkalinity tolerance of tomato plants under NaHCO3 stress. | chlorophyll fluorescence | grafting | Lycopersicon esculentum | NaHCO3 | performance index | chlorophyll fluorescence, grafting, Lycopersicon esculentum, NaHCO3, performance index | |||||
| Chlorophyll fluorescence | Pocket PEA | Ecological Engineering | Federico P.O. Mollard | University of Alberta | Department of Renewable Resources | Canada | 2013 | Typha latifolia plant performance and stand biomass in wetlandsaffected by surface oil sands mining | Stand productivity of the dominant macrophyte Typha latifolia may be constrained by salinity and pol-lution in the oil sands wetlands of northern Alberta. We compared the performance and stand biomassof T. latifolia plants established in oil sands industrial wetlands (directly exposed to byproduct processedmaterials), on-site indirectly-affected, and off-site natural wetlands. We studied T. latifolia physiology (gasexchange, leaf fluorescence), morphology, leaf chemistry, and stand biomass. Oil sands plants had lowerstomatal conductance than plants in natural wetlands resulting in lower transpiration but unaffected netphotosynthesis rates. Oil sands plants had smaller and lower numbers of green leaves than natural wet-lands plants. T. latifolia stands established in oil sands wetlands had lower aboveground and total biomasscompared to natural wetlands. Despite water chemistry differences, T. latifolia plant performance did notdiffer between oil sands wetlands types. However, there was a lower total stand biomass in industrialthan in indirectly-affected wetlands. T. latifolia had an unaltered photosynthetic activity in the oil sandswetlands allowing for the maintenance of persistent plant stands. However, T. latifolia growth restric-tions and a lower stand biomass in the oil sands wetlands probably compromise long-term reclamationobjectives focused on the accumulation of organic sediment and peat. | Cattail | Chlorophyll fluorescence | Salinity | Wetland reclamation | Cattail, Chlorophyll fluorescence, Salinity, Wetland reclamation | ||||||
| Chlorophyll fluorescence | Pocket PEA | Environmental Monitoring and Assessment | Federico P.O. Mollard | University of Alberta | Department of Renewable Resources | Canada | 2015 | Performance of wetland forbs transplanted into marshes amended with oil sands processed water | Companies mining oil sands in Alberta (Canada) face the challenge of reclaiming wetlands under water use restrictions. Wetland reclamation after mining will generate marshes characterized by elevated salinity and residual hydrocarbons. Oil sands wetlands are also impoverished in forbs, suggesting that their establishment may be constrained by water chemistry. We transplanted skullcap, mint, and smartweed plants into experimental trenches that simulated two possible reclamation scenarios: wetlands amended with on-site freshwater or with oil sands processed water (OSPW). The main scientific question was is OSPW a suitable water amendment as freshwater for reclaiming wetland forb habitat? As a surrogate of plant health, we studied plant ecophysiology (gas exchange, leaf fluorescence), leaf chemistry, and plant growth. Results showed that there were no differences in skullcap mineral contents under either treatment; however, mint and smartweed plants subjected to OSPW had a significantly higher Na content than those under freshwater. Smartweed darkadapted leaf fluorescence showed a reduced photochemistry in OSPW relative to plants in freshwater. Mint leaves exhibited lower stomatal conductance in OSPW than in freshwater, a condition that negatively affected transpiration and carboxylation. Skullcap plants grown in OSPW had lower net CO2 assimilation rates than those in freshwater but did not show any other ecophysiological difference between treatments. Mint plants experienced growth reductions (i.e., shoot height) in OSPW. Our results show, for the first time in the literature, that plants photosynthetic capacity was negatively affected by OSPW. Conditions in OSPW proved to be suitable for establishment as transplanted forbs showed 100 % survival after the first growing season. However, impaired physiological functions in plants subjected to OSPW indicated that OSPWamendment created a less hospitable habitat for wetland forbs than freshwater. | Bitumen | Effluent | Freshwater amendment | Salinity | Wetland reclamation | Bitumen, Effluent, Freshwater amendment, Salinity, Wetland reclamation | |||||
| Chlorophyll fluorescence | Pocket PEA | Photosynthetica | P. Meng | Qingdao Agricultural University | China | 2020 | Photosynthetic characteristics and chlorophyll a fluorescence induction parameters in elite clone (GS1) of Pinus sylvestris var. mongolica | We selected the elite clone of Pinus sylvestris var. mongolica ‘GS1’ from 365 clones in a primary seed orchard in Liaoning Province, China. To understand the photosynthesis characteristics and mechanisms, 40-year-old ‘GS1’ trees were compared with a common clone ‘H524’ of the same age at the same seed orchard. Results showed that ‘GS1’ had higher net photosynthetic rate because of higher stomatal conductance (gs); the larger external and inner diameters of stomata were the structural factors enabling maintenance of higher gs. The higher light-saturated net photosynthetic rate of ‘GS1’ was mainly due to higher electron transfer activity, demonstrated by the lower relative fluorescence intensity from O-step to P-step. The increase in density of active reaction centers resulted in an increase in energy flux per cross section, which led to higher photosynthetic performance. | JIP-test | light-response parameter | relative variable fluorescence | stomata size | JIP-test, light-response parameter, relative variable fluorescence, stomata size | |||||||
| Chlorophyll fluorescence | Pocket PEA | PLOS ONE | Mayank Anand Gururani | Jeju National University | Subtropical Horticulture Research Institute | South Korea | 2015 | In Vivo Assessment of Cold Tolerance through Chlorophyll-a Fluorescence in Transgenic Zoysiagrass Expressing Mutant Phytochrome A | Chlorophyll-a fluorescence analysis provides relevant information about the physiology of plants growing under abiotic stress. In this study, we evaluated the influence of cold stress on the photosynthetic machinery of transgenic turfgrass, Zoysia japonica, expressing oat phytochrome A (PhyA) or a hyperactive mutant phytochrome A (S599A) with post-translational phosphorylation blocked. Biochemical analysis of zoysiagrass subjected to cold stress revealed reduced levels of hydrogen peroxide, increased proline accumulation, and enhanced specific activities of antioxidant enzymes compared to those of control plants. Detailed analyses of the chlorophyll-a fluorescence data through the so-called OJIP test exhibited a marked difference in the physiological status among transgenic and control plants. Overall, these findings suggest an enhanced level of cold tolerance in S599A zoysiagrass cultivars as reflected in the biochemical and physiological analyses. Further, we propose that chlorophyll-a fluorescence analysis using OJIP test is an efficient tool in determining the physiological status of plants under cold stress conditions. | |||||||||||
| Chlorophyll fluorescence | Pocket PEA | Nature | Caroline A. Canham | The University of Western Australia | Australia | 2020 | Effect of elevated magnesium sulfate on two riparian tree species potentially impacted by mine site contamination | Globally, mining activities have been responsible for the contamination of soils, surface water and groundwater. Following mine closure, a key issue is the management of leachate from waste rock accumulated during the lifetime of the mine. At Ranger Uranium Mine in northern Australia, magnesium sulfate (MgSO4) leaching from waste rock has been identified as a potentially significant surface and groundwater contaminant which may have adverse affects on catchment biota. The primary objective of this study was to determine the effect of elevated levels of MgSO4 on two riparian trees; Melaleuca viridiflora and Alphitonia excelsa. We found that tolerance to MgSO4 was species-specific. M. viridiflora was tolerant to high concentrations of MgSO4 (15,300 mg l-1), with foliar concentrations of ions suggesting plants regulate uptake. In contrast, A. excelsa was sensitive to elevated concentrations of MgSO4 (960 mg l-1), exhibiting reduced plant vigour and growth. This information improves our understanding of the toxicity of MgSO4 as a mine contaminant and highlights the need for rehabililitation planning to mitigate impacts on some tree species of this region. | ||||||||||||
| Chlorophyll fluorescence | Pocket PEA | Photosynthetica | Z. X. Wang | Chinese Academy of Agricultural Sciences | Laboratory of Special Wild Plant Physiology | China | 2012 | Photosynthesis and activity of photosystem II in response to drought stress in Amur Grape (Vitis amurensis Rupr.) | The Amur Grape (Vitis amurensis Rupr.) cultivars ‘ShuangFeng’ and ‘ZuoShanyi’ were grown in shelter greenhouse under natural sunlight and subjected to drought. Sap flow rate, net photosynthetic rate (PN), and chlorophyll (Chl) fluorescence were measured on Amur Grape leaves subjected to different drought treatments. Significant decreases in PN were associated with increasing intercellular CO2 concentration (Ci), suggesting that the reduction in PN was caused by nonstomatal limitation. Analysis of OJIP transients according to the JIP-test protocol revealed that specific (per PSII reaction center) energy fluxes for light absorption, excitation energy trapping and electron transport have significantly changed. The appearance of a pronounced K-step and J-step in polyphasic rise of fluorescence transient suggested the oxygen-evolving complex and electron transport were inhibited. Drought stress has relatively little effect on the parameter maximal quantum yield of PSII photochemistry (Fv/Fm), but the performance index (PIABS) is more sensitive in different drought treatment. There are cultivar differences in the response of PSII activity to drought, the photosynthetic apparatus of ‘ZuoShanyi’ cultivar is more resistant to drought than that of ‘ShuangFeng’, and JIP-test could be a useful indicator for evaluation and selection to drought tolerance. | Amur Grape | drought stress | JIP-test | net photosynthetic rate | photosystem II | Amur Grape, drought stress, JIP-test, net photosynthetic rate, photosystem II | |||||
| Chlorophyll fluorescence | Pocket PEA | Tree Physiology | Jon Banks | The University of Reading | Department of Agriculture Policy and Development | UK | 2017 | Continuous excitation chlorophyll fluorescence parameters: a review for practitioners | This review introduces, defines and critically reviews a number of chlorophyll fluorescence parameters with specific reference to those derived from continuous excitation chlorophyll fluorescence. A number of common issues and criticisms are addressed. The parameters fluorescence origin (F0) and the performance indices (PI) are discussed as examples. This review attempts to unify definitions for the wide range of parameters available for measuring plant vitality, facilitating their calculation and use. | chlorophyll flourescence | continuous excitation | fluorescence induction kinetics | fluorescence origin | performance index | photosynthesis | chlorophyll flourescence, continuous excitation, fluorescence induction kinetics, fluorescence origin, performance index, photosynthesis | ||||
| Chlorophyll fluorescence | Handy PEA | Tree Physiology | Jon Banks | The University of Reading | Department of Agriculture Policy and Development | UK | 2017 | Continuous excitation chlorophyll fluorescence parameters: a review for practitioners | This review introduces, defines and critically reviews a number of chlorophyll fluorescence parameters with specific reference to those derived from continuous excitation chlorophyll fluorescence. A number of common issues and criticisms are addressed. The parameters fluorescence origin (F0) and the performance indices (PI) are discussed as examples. This review attempts to unify definitions for the wide range of parameters available for measuring plant vitality, facilitating their calculation and use. | chlorophyll flourescence | continuous excitation | fluorescence induction kinetics | fluorescence origin | performance index | photosynthesis | chlorophyll flourescence, continuous excitation, fluorescence induction kinetics, fluorescence origin, performance index, photosynthesis | ||||
| Chlorophyll fluorescence | FMS 2 | Environmental and Experimental Botany | Arun Kumar Shaw | West Bengal State University | Plant Stress Biology Lab | India | 2014 | Nano-CuO stress induced modulation of antioxidative defense and photosynthetic performance of Syrian barley (Hordeum vulgare L.) | Nanoparticles (NPs),a new class of pollutant has raised global environmental concern. The present study highlights the impact of nano-CuO stress on Syrian barley (Hordeum vulgare L., landrace Arabi Aswad). Seedling performances in terms of antioxidant defence and chlorophyll fluorescence were studied under three different levels of stress (0.5mM, 1mM and 1.5mM suspensions of copper II oxide, <50nm particle size, prepared in ½ MS medium) at 10 and 20 day of treatment along with control. Dose dependent reduction in shoot and root growth was recorded with passage of time. The maximal quantum yield of PSII photosynthetic apparatus (Fv/Fm) did not alter after stress application. However, performance index parameter was found to be significantly decreased irrespective of stress level and treatment period. Enhanced flavonol level with concomitant increase in APX activity found to be insufficient to enforce a light control over the H2O2 level under nano-stress. Furthermore, an impairment of the collaborative action of DHAR and MDAR in stressed leaves results in a lower ability for efficient enzymatic recycling of DHA into AsA. Overall the nano-stressed leaves exhibited significant decline in GSH/GSSG ratio that might not contribute in maintaining high GSH pool essential for sustaining balanced redox status under stress condition. In addition, an isolated increase in GR activity in 1.0 and 1.5mM nano-CuO treated leaves at 20 day does not give much protection to the nano-CuO stressed seedlings from oxidative damages. | Antioxidant | Barley | Chlorophyll fluorescence | Nanoparticle | Nanotoxicology | Antioxidant, Barley, Chlorophyll fluorescence, Nanoparticle, Nanotoxicology | |||||
| Chlorophyll fluorescence | Pocket PEA | Environmental and Experimental Botany | Arun Kumar Shaw | West Bengal State University | Plant Stress Biology Lab | India | 2014 | Nano-CuO stress induced modulation of antioxidative defense and photosynthetic performance of Syrian barley (Hordeum vulgare L.) | Nanoparticles (NPs),a new class of pollutant has raised global environmental concern. The present study highlights the impact of nano-CuO stress on Syrian barley (Hordeum vulgare L., landrace Arabi Aswad). Seedling performances in terms of antioxidant defence and chlorophyll fluorescence were studied under three different levels of stress (0.5mM, 1mM and 1.5mM suspensions of copper II oxide, <50nm particle size, prepared in ½ MS medium) at 10 and 20 day of treatment along with control. Dose dependent reduction in shoot and root growth was recorded with passage of time. The maximal quantum yield of PSII photosynthetic apparatus (Fv/Fm) did not alter after stress application. However, performance index parameter was found to be significantly decreased irrespective of stress level and treatment period. Enhanced flavonol level with concomitant increase in APX activity found to be insufficient to enforce a light control over the H2O2 level under nano-stress. Furthermore, an impairment of the collaborative action of DHAR and MDAR in stressed leaves results in a lower ability for efficient enzymatic recycling of DHA into AsA. Overall the nano-stressed leaves exhibited significant decline in GSH/GSSG ratio that might not contribute in maintaining high GSH pool essential for sustaining balanced redox status under stress condition. In addition, an isolated increase in GR activity in 1.0 and 1.5mM nano-CuO treated leaves at 20 day does not give much protection to the nano-CuO stressed seedlings from oxidative damages. | Antioxidant | Barley | Chlorophyll fluorescence | Nanoparticle | Nanotoxicology | Antioxidant, Barley, Chlorophyll fluorescence, Nanoparticle, Nanotoxicology | |||||
| Chlorophyll fluorescence | Pocket PEA | Journal of the Korean Society for Applied Biological Chemistry | Mark Christian Felipe Reveche Redillas | Myongji University | School of Biotechnology and Environmental Engineering | South Korea | 2011 | JIP Analysis on Rice (Oryza sativa cv Nipponbare) Grown under Limited Nitrogen Conditions | Nitrogen deficiency significantly reduces the CO2 assimilation capacity of plants and the quantum yield of photosynthesis. Here, we employed the JIP test to determine the effects of nitrogendeficiency on the plant's photosysnthetic ability on the basis of chlorophyll fluorescence. Nitrogendeficient and nitrogen-replete rice plants were analyzed for the fluorescence transients of the plant leaves in comparison with the nitrogen-sufficient controls. Results showed that 7 day-replete plants behaved normally while 5, 3, and 1 day-replete plants were significantly affected from nitrogen starvation. More specifically, nitrogen starvation of plants resulted in an inactivation of photosystem II (PS II) reaction centers and a decline in electron transport beyond the reduced plastoquinone (QA − ), and a decrease in both the pool size and the reduction of end electron acceptors at the PS I. The affected plants were fully recovered from the deficiency after 7 days of nitrogen repletion, as evidenced by the similar level of fluorescence transients to the positive controls. Thus, our results demonstrated that the movement of electron carriers leading to the reduction of end electron acceptors was affected by nitrogen limitation leading to a more pronounced decrease in the reduction of end electron acceptors. Together with the fact that nitrogen-deficiency limits the CO2 assimilation of plants, this study indicates that nitrogen metabolism is tightly coupled with photosynthetic ability. | chlorophyll fluorescence | JIP test | nitrogen | Oryza sativa | chlorophyll fluorescence, JIP test, nitrogen, Oryza sativa | ||||||
| Chlorophyll fluorescence | Pocket PEA | PLOS ONE | Allan Silva Pereira | Universidade Estadual de Santa Cruz | Departamento de Ciências BioloÂgicas | Brasil | 2017 | Combining ability, heritability and genotypic relations of different physiological traits in cacao hybrids | Selecting parents and evaluating progenies is a very important step in breeding programs and involves approaches such as understanding the initial stages of growth and characterizing the variability among genotypes for different parameters, such as physiological, growth, biomass partitioning and nutrient translocation to the aerial part. In these cases, facilitating tools can be used to understand the involved gene dynamics, such as diallel crosses and genetic and phenotypic correlations. Our main hypothesis is that the contrasting phenotypes of these parental genotypes of cocoa used are due to genetic factors, and progenies derived from crosses of these parental genotypes are useful for breeding programs related to plant architecture, physiological parameters and translocation of mineral nutrients. We aimed to evaluate the combining abilities in progenies of cacao (Theobroma cacao L) originating from contrasting parents for canopy vigor. Emphasis was given to the evaluation of morphological and physiological parameters and the phenotypic and genotypic correlations to understand the dynamics of the action of the genes involved, as well as in expression profile from genes of gibberellins biosynthesis pathway in the parents. Fifteen F1 progenies were obtained from crosses of six clones (IMC 67, P4B, PUCALA, SCA 6, SCA 24 and SJ 02) that were evaluated in a randomized complete block design with four replicates of 12 plants per progeny, in a balanced half table diallel scheme. It is possible to identify and select plants and progenies of low, medium and high height, as there is expressive genetic variability for the evaluated parameters, some of these on higher additive effects, others on larger nonadditive effects and others under a balance of these effects. Most physiological parameters evaluated show that for selection of plants with the desired performance, no complex breeding methods would be necessary due to the high and medium heritability observed. Strong genetic components were observed from many of the correlations, which indicate the possibility to formulate selection indices for multi-traits, such as dwarfism or semidwarfism, tolerance to increase of leaf sodium concentrations and maintenance of the photosynthetic apparatus integrity under these conditions. Additionally, plants with higher carbon fixation, better water use, higher carboxylation efficiency and greater magnesium accumulation in leaves can be selected. | |||||||||||
| Chlorophyll fluorescence | Pocket PEA | Plant Molecular Biology | Zhi‑Fang Zuo | Jeju National University | Department of Biotechnology | South Korea | 2020 | A novel basic helix-loop-helix transcription factor, ZjICE2 from Zoysia japonica confers abiotic stress tolerance to transgenic plants via activating the DREB/CBF regulon and enhancing ROS scavenging | The basic helix-loop-helix (bHLH) family transcription factors (TFs) play an important role in response to biotic or abiotic stresses in plants. However, the functions of bHLH TFs in Zoysia japonica, one of the warm-season turfgrasses, remain poorly understood. Here, we identified ZjICE2 from Z. japonica, a novel MYC-type bHLH transcription factor that was closely related to ICE homologs in the phylogenetic tree, and its expression was regulated by various abiotic stresses. Transient expression of ZjICE2-GFP in onion epidermal cells revealed that ZjICE2 was a nuclear-localized protein. Also, ZjICE2 bound the MYC cis-element in the promoter of dehydration responsive element binding 1 of Z. japonica (ZjDREB1) using yeast one-hybrid assay. A phenotypic analysis showed that overexpression of the ZjICE2 in Arabidopsis enhanced tolerance to cold, drought, and salt stresses. The transgenic Arabidopsis and Z. japonica accumulated more transcripts of cold-responsive DREB/CBFs and their downstream genes than the wild type (WT) after cold treatment. Furthermore, the transgenic plants exhibited an enhanced Reactive oxygen species (ROS) scavenging ability, which resulted in an efficient maintenance of oxidant–antioxidant homeostasis. In addition, overexpression of the ZjICE2 in Z. japonica displayed intensive cold tolerance with increases in chlorophyll contents and photosynthetic efficiency. Our study suggests that ZjICE2 works as a positive regulator in abiotic stress responses and the ICE-DREB/CBFs response pathway involved in cold stress tolerance is also conserved in Z. japonica. These results provide a valuable genetic resource for the molecular breeding program especially for warm-season grasses as well as other leaf crop plants. | Abiotic stresses | bHLH | DREB/CBFs | Overexpression | ZjICE2 | Zoysia japonica | Abiotic stresses, bHLH, DREB/CBFs, Overexpression, ZjICE2, Zoysia japonica | ||||
| Chlorophyll fluorescence | Pocket PEA | Physiology and Molecular Biology of Plants | Jie Wang | Anhui Agricultural University | Vegetable Genetics and Breeding Laboratory | China | 2020 | Response of photosynthetic capacity and antioxidative system of chloroplast in two wucai (Brassica campestris L.) genotypes against chilling stress | Chilling stress during the growing season could cause a series of changes in wucai (Brassica campestris L.). WS-1 (chilling-tolerant genotype) and Ta2 (chilling-sensitive genotype) were sampled in present study to explore the chilling tolerance mechanisms. Our results indicated that photosynthetic parameters exhibited lower level in Ta2 than in WS-1 under chilling stress. The rapid chlorophyll fluorescence dynamics curve showed that chilling resulted in a greater inactivation of photosystem II reaction center in Ta2. Reactive oxygen species and malondialdehyde content of chloroplast in Ta2 were higher than WS-1. The ascorbate–glutathione cycle in chloroplast of WS-1 played a more crucial role than Ta2, which was confirmed by higher activities of antioxidant enzymes including Ascorbate peroxidase, Glutathione reductase, Monodehydroascorbate reductase and Dehydroascorbate reductase and higher content of AsA and GSH. In addition, the ultrastructure of chloroplasts in Ta2 was more severely damaged. After low temperature stress, the shape of starch granules in Ta2 changed from elliptical to round and the volume became larger than that of WS-1. The thylakoid structure of Ta2 also became dispersed from the original tight arrangement. Combined with our previous study under heat stress, WS-1 can tolerant both chilling stress and heat stress, which was partly due to a stable photosynthetic system and the higher active antioxidant system in plants, in comparison to Ta2. | AsA-GSH cycle | Low temperature stress | Thylakoid | OJIP test | AsA-GSH cycle, Low temperature stress, Thylakoid, OJIP test | ||||||
| Chlorophyll fluorescence | Pocket PEA | Theoretical and Experimental Plant Physiology | Jefferson Rangel da Silva | Instituto Agronomico | Centro de Citricultura Sylvio Moreira | Brasil | 2020 | Endophytic diazotrophic bacteria mitigate water deprivation effects in pineapple explants during acclimatization | We examined physiological and growth promotion traits in water-deprived pineapple explants inoculated with two endophytic diazotrophic bacteria. The following questions were addressed: (i) Is the root inoculation efficient to increase bacteria population associated to pineapple explants? (ii) Are nutrient concentrations improved in pineapple explants in response to endophytic bacteria inoculation? (iii) Can endophytic bacteria improve pineapple explants’ growth and photosynthesis? (iv) Is it possible to mitigate water deprivation negative effects and facilitate pineapple explants’ acclimatization using endophytic diazotrophic bacteria? Pineapple ‘Vito´ria’ explants grown in vitro were inoculated with two different bacteria species. Therefore, 10 mL of bacteria suspension (108 cells mL-1) of either Burkholderia silvatlantica strain UENF 117111 or Herbaspirillum seropedicae strain HRC54 were applied in the substrate after transplantation. Uninoculated explants received 10 mL of autoclaved DYGS liquid medium (Control treatment). These treatments were subdivided in two water regimes, so that explants were either full-irrigated (FI) or non-irrigated (NI) for 24 days. Thereafter, NI explants were re-irrigated to saturation for two days. We found that: (i) The inoculation was efficient to increase bacteria associated to the plantlets; (ii) Nutrient concentrations were not improved in pineapple explants inoculated with both bacteria species; (iii) B. silvatlantica did not change both growth and photosynthetic capacity of the explants. Nonetheless, H. seropedicae inoculation caused negative effects on growth, whereas Anet was increased; (iv) The use of both bacteria delayed water deprivation effects and maintained the photosynthetic capacity through C3 metabolism intact for longer periods under water deprivation, as well as by recovering Anet after re-irrigation. | Photosynthetic capacity | Crassulacean acid metabolism | Ananas comosus | Burkholderia silvatlantica | Herbaspirillum seropedicae | Photosynthetic capacity, Crassulacean acid metabolism, Ananas comosus, Burkholderia silvatlantica, Herbaspirillum seropedicae | |||||
| Chlorophyll fluorescence | Pocket PEA | Scientia Horticulturae | Qian Zha | Shanghai Academy of Agricultural Sciences | Research Institute of Forestry and Pomology | China | 2020 | Transcriptomic analysis of the leaves of two grapevine cultivars under hightemperature stress | The frequent occurrence of extremely high temperatures can severely affect agricultural production. In grapevines, elevated temperatures can cause irreversible damage during the fruit ripening period. The suggested main approach for addressing this challenge is breeding high-temperature-resistant varieties, which makes it critical to identify key genes involved in the heat stress molecular regulatory network of grapevines. In this study, we exposed the saplings of two grapevine varieties, “Shenfeng” and “Shenhua,” to 45 °C for 3 and 6 h. After 3 h of temperature stress, the leaves of “Shenfeng” appeared dehydrated, and after 6 h, the whole plants had dried up. In contrast, the leaves and the apex of “Shenhua” stem showed only mild water loss and wilt symptoms after 6 h, indicating that this cultivar has strong heat resistance. In response to the 45 °C high-temperature stress, and compared to their levels at 0 h, 822, 501, and 1161 genes showed differential expression levels in “Shenfeng” after 3 h and in “Shenhua” after 3 and 6 h of treatment, respectively; 233 of these genes showed differential expression patterns in the three comparisons. Statistical analysis of these differentially expressed genes revealed that the most up-regulated metabolic pathways in both cultivars were endoplasmic reticulum protein processing and plant hormone signal transduction. Our data indicates that among heat shock transcription factor (HSF) family genes, the HSFA2 and HSFA7 were the most heat-sensitive, and that HSF and HSP cooperated to response adversity. Photosystem II (PSII) functioned more efficiently in heat-tolerant rather than in heat-sensitive grapevines, leading to differences in the PSII parameters and transcriptional levels of key PSII protein-coding genes between the cultivars. We can conclude that, in response to high-temperature stress, interactions among endogenous hormone-mediated plant defense processes and the ABA response pathway have great research value. | Heat shock transcription factors | Heat shock protein | Photosystem II | Hormone | Heat shock transcription factors, Heat shock protein, Photosystem II, Hormone | ||||||
| Chlorophyll fluorescence | Pocket PEA | Journal of Proteome Research | Zhou Li | Sichuan Agricultural University | Department of Grassland Science | China | 2020 | Proteomic and metabolomic profilings reveal crucial function of #-aminobutyric acid (GABA) on regulating ionic, water, and metabolic homeostasis in creeping bentgrass under salt stress | The global emergence of soil salinization poses a serious challenge to many countries and regions. γ-Aminobutyric acid (GABA) is involved in systemic regulation of plant adaptation to salt stress, but the underlying molecular and metabolic mechanism still remain largely unknown. The elevated endogenous GABA level by the application of exogenous GABA improved salt tolerance associated with the enhancement of antioxidant capacity, photosynthetic characteristics, osmotic adjustment (OA), and water use efficiency in creeping bentgrass. GABA strongly upregulated transcript levels of AsPPa2, AsATPaB2, AsNHX2/4/6, and AsSOS1/20 in roots involved in enhanced capacity of Na+ compartmentalization and mitigation of Na+ toxicity in cytosol. Significant downregulation of AsHKT1/4 expression could be induced by GABA in leaves in relation to maintenance of significantly lower Na+ content and higher K+/Na+ ratio. GABA-depressed aquaporins (AQPs) expression and accumulation induced declines in stomatal conductance and transpiration, thereby reducing water loss in leaves during salt stress. For metabolic regulation, GABA primarily enhanced sugars and amino acids accumulation and metabolism largely contributing to improved salt tolerance through maintaining OA and metabolic homeostasis. Other major pathways could be related to GABA-induced salt tolerance including increases in antioxidant defense, heat shock proteins, and myo-inositol accumulation in leaves. Integrative analyses of molecular, protein, metabolic, and physiological changes reveal systemic function of GABA on regulating ions, water, and metabolic homeostasis in non-halophytic creeping bentgrass under salt stress. | amino acid | gene expression | metabolic pathways | metabolomics | proteomics | stress signal | amino acid, gene expression, metabolic pathways, metabolomics, proteomics, stress signal | ||||
| Chlorophyll fluorescence | Pocket PEA | MDPI: Water | Shokoofeh Hajihashemi | Behbahan Khatam Alanbia University of Technology | Plant Biology Department | Iran | 2020 | Effect of Wastewater Irrigation on Photosynthesis, Growth, and Anatomical Features of Two Wheat Cultivars (Triticum aestivum L.) | The wastewater from the Razi petrochemical complex contains high levels of salts and heavy metals. In the present research, the e ects of di erent wastewater dilution levels (0, 25%, 50%, and 100%) were studied on two wheat cultivars—Chamran and Behrang. The wastewater contained high levels of NH4+, NO3-, PO43-, and SO42-, and Mg, Ca, K, Na, Cu, Zn, Fe, M, and Ni. The toxic levels of mineral elements in the wastewater resulted in a significant decline in the K, P, Si, and Zn content of leaves. Irrigation with the wastewater resulted in a significant reduction in photosynthetic characteristics including chlorophyll fluorescence (Fv/Fm and PIABS), intercellular CO2, net photosynthesis, water use e ciency, and photosynthetic pigments. The reduction in photosynthesis was followed by a significant decrease in the carbohydrate content and, subsequently, plant height, leaf area, and grain yield. Increasing the wastewater concentration reduced leaf thickness and root diameter, accounting for the decrease in xylem and phloem vessels, the root cortical parenchyma, and mesophyll thickness. The bulliform cell size increased under wastewater treatment, which may suggest induction of a defense system against water loss through leaf rolling. Based on the observed negative e ect of wastewater on physiology, morphology, anatomy, and yield of two wheat cultivars, reusing wastewater with high levels of total suspended solids and salts for irrigation cannot be approved for wheat crops. | growth | leaf anatomy | photosynthetic process | root anatomy | wastewater | wheat | growth, leaf anatomy, photosynthetic process, root anatomy, wastewater, wheat | ||||
| Chlorophyll fluorescence | Pocket PEA | Scientia Horticulturae | Filippos Bantis | Aristotle University | Department of Horticulture | Greece | 2019 | Bichromatic red and blue LEDs during healing enhance the vegetative growth and quality of grafted watermelon seedlings | Watermelon is an economically important crop that is exclusively established through the use of grafted seedlings. Grafting procedure and the period of healing are critical for the production of high quality seedlings. During healing, grafted seedlings are grown in a chamber with controlled conditions, including supplementary lighting. The aim of the present study was to evaluate the impact of commonly used fluorescent (FL, control) lamps or light-emitting diodes (LEDs) with varying red (R) and blue (B) proportions [100 % R (R), 12 % B and 88 % R (12B), 24 % B and 76 % R (24B), 36 % B and 64 % R (36B) or 100 % B (B)] employed in the healing chamber on the quality of grafted watermelon seedlings. Seedlings under FL and B performed poorly in almost all tested parameters compared to the other LEDs. However, monochromatic B led to the greatest rates of photosynthesis (Pmax), stomatal conductance (g) and transpiration (E). On the contrary, R promoted the seedling length, fresh and dry weight (FW and DW) of shoots and roots, and root-to-shoot ratio (R/S) but led to inferior gas exchange and photosynthetic efficiency (Fv/Fm). B addition to R light (12B and 24B) enhanced the morphological and growth characteristics tested at least as much as R light or even more (leaf area, shoot DW). It should be noted that the entire root system of the seedlings was cut off during the grafting procedure and its re-growth was highly promoted by dichromatic LEDs (R plus B). Altogether, the above results demonstrate that R light with addition of low proportion of B light (12–24%) enhances the production of high quality grafted watermelon seedlings. | Citrulus lanatus | Light-emitting diodes | Growth chamber | Photomorphogenesis | Root system | Photosynthetic activity | Citrulus lanatus, Light-emitting diodes, Growth chamber, Photomorphogenesis, Root system, Photosynthetic activity | ||||
| Chlorophyll fluorescence | Pocket PEA | MDPI: Plants | Lorenzo Guzzetti | University of Milan-Bicocca | Department of Biotechnology and Bioscience | Italy | 2019 | Sustainability Perspectives of Vigna unguiculata L. Walp. Cultivation under No Tillage and Water Stress Conditions | Nowadays, agriculture is facing the great challenge of climate change which puts the productivity of the crops in peril due to unpredictable rain patterns and water shortages, especially in the developing world. Besides productivity, nutritional values of the yields of these crops may also be affected, especially under low mechanization and the low water availability conditions of the developing world. Conservation agriculture (CA) is a topic of emerging interest due to the provision of adequate yields and reduced environmental impact, such as greenhouse gas emissions, by being based on three main principles: minimum soil disturbance (reduced or no tillage), cover crop maintenance, and crop rotation. The aim of this study was to assess the impact of CA management on the growth performance and the nutritional profile of cowpea (Vigna unguiculata L.Walp), a pulse of African origin, commonly known as black eye bean under field conditions. A field experiment was designed to assess the effect of conventional tillage (CT) and no-tillage (NT) combined with the usage of a set of cover crops, coupled to normal and deficient water regimes. Cowpea was revealed to be able to grow and yield comparably at each level of the treatment tested, with a better ability to face water exhaustion under CA management. After a faster initial growth phase in CT plots, the level of adaptability of this legume to NT was such that growth performances improved significantly with respect to CT plots. The flowering rate was higher and earlier in CT conditions, while in NT it was slower but longer-lasting. The leafy photosynthetic rate and the nutritional profile of beans were slightly influenced by tillage management: only total starch content was negatively affected in NT and watered plots while proteins and aminoacids did not show any significant variation. Furthermore, significantly higher carbon and nitrogen concentration occurred inNT soils especially at the topmost (0–5 cm) soil horizon. These findings confirm the capability of CA to enrich soil superficial horizons and highlight that cowpea is a suitable crop to be grown under sustainable CAmanagement. This practice could be pivotal to preserve soils and to save agronomical costswithout losing a panel of nutrients that are important to the human diet. Due to its great protein and aminoacidic composition, V. unguiculata is a good candidate for further cultivation in regions of the word facing deficiencies in the intake of such nutrients, such as the Mediterranean basins and Sub-Saharan countries. | conservation agriculture | no-tillage | climate change | drought stress | conservation agriculture, no-tillage, climate change, drought stress | ||||||
| Chlorophyll fluorescence | Pocket PEA | Potato Research | Anna J. Keutgen | BOKU-University of Natural Resources and Life Sciences | Division of Vegetables and Ornamentals at the Department of Crop Sciences | Austria | 2019 | Evaluation of Photosynthetic and Yield Traits in Ten Potato Clones and Cultivars Under Farming Conditions in Poland | Photosynthetic properties and tuber yield were compared in seven tetraploid potato (Solanum tuberosum L.) clones (‘13-VIII-10’, ‘13-VIII-27’, ‘13-VIII-45’, ‘13-VIII-49’, ‘13-VIII-50’, ‘13-VIII-60’, ‘TG-97-403’) and three cultivars (‘Jelly’, ‘Satina’, ‘Tajfun’) at four localities in Poland under either integrated (Młochów, Boguchwała) or organic (Radzików, Chwałowice) fertilisation conditions applying the ‘OJIP’ analysis of chlorophyll fluorescence kinetics. The yield-relevant parameters of leaf pigment content and chlorophyll fluorescence were used to rank the tested clones and cultivars applying multidimensional comparative analysis. The results indicate that the clones 13-VIII-10 and 13-VIII-45 cannot be recommended for cultivation, while cv. Taifun performed the best. The assessment of the efficiency of the light reactions of photosynthesis produced a different ranking, indicating that the efficiency is not related to yield, but characterises the balance between light harvesting and dark reactions of photosynthesis. In this respect, the light reactions of photosynthesis were least balanced in clone 13-VIII-49 and cv. Jelly while those of cv. Taifun and clone 13-VIII-60 were the best. The effect of the production system was of minor significance for tuber yield, but local factors dominated. Only in the case of chlorophyll (Chl) and carotenoid (Car) contents of leaves did an effect of the production system became evident, favouring integrated over organic cultivation. By contrast, most of the chlorophyll fluorescence parameters were controlled by soil nitrogen content, including maximum quantum yield for primary photochemistry (φP0) and the absolute and total performance indices (PIAbs, PITotal). Within a production system precipitation affected the ratio Car/total Chl content. | Chlorophyll a fluorescence | Chlorophyll b/a ratio | OJIP transient | Solanum tuberosum L | Chlorophyll a fluorescence, Chlorophyll b/a ratio, OJIP transient, Solanum tuberosum L | ||||||
| Chlorophyll fluorescence | Pocket PEA | Scientia Horticulturae | Fatemeh Sadeghi | University of Hormozgan | Department of Horticultural Sciences | Iran | 2019 | Fungal endophytes alleviate drought-induced oxidative stress in mandarin (Citrus reticulata L.): Toward regulating the ascorbate–glutathione cycle | Fungal endophytes grow symbiotically inside a diverse array of plants, and improve viability of the hosts in various mutualistic manners. We investigated the effects of inoculating mandarin endophytic fungi, introduced formerly by our group, i.e. Penicillium citrinum, Aurobassium pullunts and Dothideomycetes sp., individually and in combination with each other on the reactive oxygen species (ROS) scavenging and antioxidant functions in plants under drought stress. To do so, mandarin (Citrus reticulata) scions grafted on Bakraii [Citrus reticulata×Citrus limetta] (Mandarin/Bakraii) were subjected to four irrigations interval including 2, 4, 6 and 8 days, in present/absent of the fungal endophytes. The results indicated that drought stress significantly reduced growth, chlorophyll, carotenoid content and chlorophyll fluorescence (Fv/Fm) of the plants lacking endophytes. Combinatory applications with three fungal endophytes (P. citrinum + A. pullunts+Dothideomycetes sp.) significantly improved the above-mentioned parameters under drought stress. H2O2, O2 − and lipid peroxidation level were significantly reduced in the plants inoculated with fungal endophytes. Drought stress significantly increased activities of ascorbate peroxidase (APX), superoxide dismutase (SOD) and glutathione reductase (GR) and levels of ascorbate (ASA) and glutathione (GSH) and decreased activities of catalase (CAT), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR). Fungal endophytes inoculated drought stressed seedlings enhanced the above-mentioned indicators as compared to the drought-stressed plants without fungal endophytes, as well as in the ratios of reduced ascorbate/dehydroascorbic acid (AsA/DHA) and reduced glutathione/oxidized glutathione (GSH/GSSG). Overall, fungal endophyte inoculation improved drought tolerance and reduced the accumulation of ROS by increasing their scavenging via improving the redox state of ascorbate and glutathione and promotion of antioxidant enzymes activity. | Citrus reticulate | Fungal endophyte | Drought | Reactive oxygen species (ROS) | Ascorbate–glutathione cycle | Citrus reticulate, Fungal endophyte, Drought, Reactive oxygen species (ROS), Ascorbate–glutathione cycle | |||||
| Oxygen electrode | Oxygraph | Biochemical Journal | Josefa Hernandez-Ruiz | Universidad de Murcia | Departamento de Biologia Vegetal (Fisiologia Vegetal) | Spain | 2001 | Catalase-like activity of horseradish peroxidase: relationship to enzyme inactivation by H2O2 | H2O2 is the usual oxidizing substrate of horseradish peroxidase C (HRP-C). In the absence in the reaction medium of a oneelectron donor substrate, H2O2 is able to act as both oxidizing and reducing substrate. However, under these conditions the enzyme also undergoes a progressive loss of activity. There are several pathways that maintain the activity of the enzyme by recovering the ferric form, one of which is the decomposition of H2O2 to molecular oxygen in a similar way to the action of catalase. This production of oxygen has been kinetically characterized with a Clark-type electrode coupled to an oxygraph. HRP-C exhibits a weak catalase-like activity, the initial reaction rate of which is hyperbolically dependent on the H2O2 concentration, with values for K2 (affinity of the first intermediate, compound I, for H2O2) and k3 (apparent rate constant controlling catalase activity) of 4.0³0.6 mM and 1.78³0.12 s−" respectively. Oxygen production by HRP-C is favoured at pH values greater than approx. 6.5 ; under similar conditions HRPC is also much less sensitive to inactivation during incubations with H2O2. We therefore suggest that this pathway is a major protective mechanism of HRP-C against such inactivation. | horseradish peroxidase C | oxygen | protection | horseradish peroxidase C, oxygen, protection | |||||||
| Oxygen electrode | Oxygraph | Biochemistry (Moscow) | A. Ghosh | Indian Association for the Cultivation of Science | Department of Biological Chemistry | India | 2011 | Differential Inhibition/Inactivation of Mitochondrial Complex I Implicates Its Alteration in Malignant Cells | Methylglyoxal strongly inhibited mitochondrial respiration of a wide variety of malignant tissues including sarcoma of mice, whereas no such significant effect was noted on mitochondrial respiration of normal tissues with the exception of cardiac cells. This inhibition by methylglyoxal was found to be at the level of mitochondrial complex I (NADH dehydrogenase) of the electron transport chain. L Lactaldehyde, which is structurally and metabolically related to methylglyoxal, could protect against this inhibition. NADH dehydrogenase of submitochondrial particles of malignant and cardiac cells was inhibited by methylglyoxal. This enzyme of these cells was also inactivated by methylglyoxal. The possible involvement of lysine residue(s) for the activity of NADH dehydrogenase was also investigated by using lysine specific reagents trinitrobenzenesulfonic acid (TNBS) and pyridoxal 5′ phosphate (PP). Inactivation of NADH dehydrogenase by both TNBS and PP convincingly demonstrated the involvement of lysine residue(s) for the activity of the sarcoma and cardiac enzymes, whereas both TNBS and PP failed to inactivate the enzymes of skeletal muscle and liver. Together these studies demonstrate a specific effect of methylglyoxal on mitochondrial complex I of malignant cells and importantly some distinct alteration of this complex in cancer cells. | sarcoma | NADH dehydrogenase | methylglyoxal | lactaldehyde | sarcoma, NADH dehydrogenase, methylglyoxal, lactaldehyde | ||||||
| Oxygen electrode | Oxygraph | Biochimica et Biophysica Acta | Zsofia Komary | Semmelweis University | Department of Medical Biochemistry | Hungary | 2008 | H2O2 generation is decreased by calcium in isolated brain mitochondria | Release of H2O2 in response to Ca2+ loads (1–100 μM) was investigated using Amplex red fluorescent assay in isolated guinea-pig brain mitochondria respiring on glutamate plus malate or succinate. In mitochondria challenged with Ca2+ (10 μM), in the absence of adenine nucleotides and inhibitors of the respiratory chain, the rate of H2O2 release, taken as an indication of H2O2 production, was decreased by 21.8±1.6% in the presence of NADH-linked substrates and by 86.5±1.8% with succinate. Parallel with this, a Ca2+-induced loss in NAD(P)H fluorescence, sustained depolarization, decrease in fluorescent light scattering signal and in calcein fluorescence were detected indicating an increased permeability and swelling of mitochondria, which were prevented by ADP (2 mM). In the presence of ADP H2O2 release from mitochondria was decreased, but Ca2+ no longer influenced the generation of H2O2.We suggest that the decreased H2O2 generation induced by Ca2+ is related to depolarization and NAD(P)H loss resulting from a non-specific permeability increase of the mitochondrial inner membrane. | Mitochondria | Calcium | Oxidative stress | Mitochondrial permeability transition | pore (mPTP) | Reactive Oxygen Species | NADH | Mitochondria, Calcium, Oxidative stress, Mitochondrial permeability transition, pore (mPTP), Reactive Oxygen Species, NADH | |||
| Oxygen electrode | Oxygraph | Journal Of Bacteriology | Karen E. Keith | University of Western Ontario | Departments of Microbiology and Immunology | Canada | 2007 | Burkholderia cenocepacia C5424 Produces a Pigment with Antioxidant Properties Using a Homogentisate Intermediate | Burkholderia cenocepacia is a gram-negative opportunistic pathogen that belongs to the Burkholderia cepacia complex. B. cenocepacia can survive intracellularly within phagocytic cells, and some epidemic strains produce a brown melanin-like pigment that can scavenge free radicals, resulting in the attenuation of the host cell oxidative burst. In this work, we demonstrate that the brown pigment produced by B. cenocepacia C5424 is synthesized from a homogentisate (HGA) precursor. The disruption of BCAL0207 (hppD) by insertional inactivation resulted in loss of pigmentation. Steady-state kinetic analysis of the BCAL0207 gene product demonstrated that it has 4-hydroxyphenylpyruvic acid dioxygenase (HppD) activity. Pigmentation could be restored by complementation providing hppD in trans. The hppD mutant was resistant to paraquat challenge but sensitive to H2O2 and to extracellularly generated superoxide anions. Infection experiments in RAW 264.7 murine macrophages showed that the nonpigmented bacteria colocalized in a dextran-positive vacuole, suggesting that they are being trafficked to the lysosome. In contrast, the wild-type strain did not localize with dextran. Colocalization of the nonpigmented strain with dextran was reduced in the presence of the NADPH oxidase inhibitor diphenyleneiodonium, and also the inducible nitric oxide inhibitor aminoguanidine. Together, these observations suggest that the brown pigment produced by B. cenocepacia C5424 is a pyomelanin synthesized from an HGA intermediate that is capable of protecting the organism from in vitro and in vivo sources of oxidative stress. | |||||||||||
| Oxygen electrode | Oxygraph | Journal of Phycology | Herman Carr | Stockholm University | Department of Botany | Sweden | 2003 | A Methodological Comparison Of Photosynthetic Oxygen Evolution And Estimated Electron Transport Rate In Tropical Ulva (Chlorophyceae) Species Under Different Light And Inorganic Carbon Conditions | Gross oxygen evolution was compared with the electron transport rate (ETR), estimated from chl a fluorescence parameters on the common tropical green macro alga Ulva fasciata Delile with confirmatory carbon saturation curves from U. reticulata Forska°l. Theoretically, the relationship between estimated ETR and gross oxygen evolution should be 4:1, that is, four electrons are transported through PSII for each molecule of oxygen evolved. However, deviations of the 4:1 relationship have previously been reported. Measurements were conducted with two commercially available and portable pulse amplitude modulated (PAM) chl fluorometers. We sought experimental approaches that minimize discrepancies between the two different measuring techniques of photosynthetic rates, both for in situ and laboratory conditions. Using fresh algal tissue for each of the different irradiances gave the best fit of gross oxygen evolution and ETR even at irradiances above light saturation, where large discrepancies between oxygen evolution and ETR are common. With increasing dissolved inorganic carbon (DIC) concentrations, there was a curvilinear response of gross oxygen evolution in relation to ETR. We therefore suggest to establish DIC saturation curves in the laboratory, oxygen evolution is probably the most relevant choice. Photorespiration could not readily explain a curvilinear response of O2 evolution and proportionally higher ETR at high irradiances. ETRs measured with the rapid light curve function of the PAM were compared with steady-state rates of gross and net oxygen evolution, and the ETR was found to decrease at higher irradiances whereas oxygen evolution was constant. | algae | dissolved inorganic carbon concentration | irradiance | oxygen evolution | photosynthetic rates | PAM chl fluorometry | PSII | algae, dissolved inorganic carbon concentration, irradiance, oxygen evolution, photosynthetic rates, PAM chl fluorometry, PSII | |||
| Oxygen electrode | Oxygraph | The International Journal of Biochemistry & Cell Biology | Silvina S. Bombicino | University of Buenos Aires | Institute of Biochemistry and Molecular Medicine | Argentina | 2016 | Diabetes impairs heart mitochondrial function without changes inresting cardiac performance | Diabetes is a chronic disease associated to a cardiac contractile dysfunction that is not attributable tounderlying coronary artery disease or hypertension, and could be consequence of a progressive dete-rioration of mitochondrial function. We hypothesized that impaired mitochondrial function precedesDiabetic Cardiomyopathy. Thus, the aim of this work was to study the cardiac performance and heartmitochondrial function of diabetic rats, using an experimental model of type I Diabetes. Rats were sacri-ficed after 28 days of Streptozotocin injection (STZ, 60 mg kg−1, ip.). Heart O2consumption was declined,mainly due to the impairment of mitochondrial O2uptake. The mitochondrial dysfunction observed indiabetic animals included the reduction of state 3 respiration (22%), the decline of ADP/O ratio (∼15%) andthe decrease of the respiratory complexes activities (22–26%). An enhancement in mitochondrial H2O2(127%) and NO (23%) production rates and in tyrosine nitration (58%) were observed in heart of diabeticrats, with a decrease in Mn-SOD activity (∼50%). Moreover, a decrease in contractile response (38%),inotropic (37%) and lusitropic (58%) reserves were observed in diabetic rats only after a -adrenergicstimulus. Therefore, in conditions of sustained hyperglycemia, heart mitochondrial O2consumption andoxidative phosphorylation efficiency are decreased, and H2O2and NO productions are increased, leadingto a cardiac compromise against a work overload. This mitochondrial impairment was detected in theabsence of heart hypertrophy and of resting cardiac performance changes, suggesting that mitochondrialdysfunction could precede the onset of diabetic cardiac failure, being H2O2, NO and ATP the moleculesprobably involved in mitochondrion-cytosol signalling. | Type I diabetes | Streptozotocin (STZ) | Cardiac and mitochondrial dysfunction | Mitochondrial nitric oxide synthase (mtNOS) | Oxidative stress | Isoproterenol (ISO) | Type I diabetes, Streptozotocin (STZ), Cardiac and mitochondrial dysfunction, Mitochondrial nitric oxide synthase (mtNOS), Oxidative stress, Isoproterenol (ISO) | ||||
| Oxygen electrode | Oxygraph | Andrology | A. Ferramosca | Universit a del Salento | Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali | Italy | 2016 | A high-fat diet negatively affects rat sperm mitochondrial respiration | Recent evidences have linked abdominal obesity, insulin resistance, and dyslipidemia to male infertility. Since a defective energy metabolism may play an important role in the impairment of sperm quality, the aim of this study is to investigate the sperm energetic metabolism in rats fed with a high-fat diet, an animal model associated with metabolic syndrome development. Sexually mature male Sprague–Dawley rats were divided into two groups and fed for 4 weeks a standard diet (control group) or a diet enriched in 35% of fat (high fat group). Liver and adipose tissue weight, plasma glucose, insulin, and lipid concentrations were determined. Activities of enzymes involved in sperm energetic metabolism were evaluated by spectrophotometric assays. Sperm mitochondrial respiratory activity was evaluated with a polarographic assay of oxygen consumption. The administration of a high-fat diet caused a significant increase in body weight of rats and provoked hyperglycemia, hyperinsulinemia, and dyslipidemia. In these animals, we also observed a reduction in sperm concentration and motility. The investigation of sperm energetic metabolism in animals fed a high-fat diet revealed an impairment in the activity of pyruvate and lactate dehydrogenase, citrate synthase, and respiratory chain complexes. A parallel reduction in the cellular levels of adenosine triphosphate (ATP) and an increase in oxidative damage were also observed. A defective energy metabolism may play an important role in the impairment of sperm quality in the high-fat diet fed rats. | High-fat diet | male infertility | metabolic syndrome | sperm mitochondria | High-fat diet, male infertility, metabolic syndrome, sperm mitochondria | ||||||
| Oxygen electrode | Oxygraph | International Journal of Andrology | A.Ferramosca | Universit a del Salento | Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali | Italy | 2007 | Oxygen uptake by mitochondria in demembranated human spermatozoa: a reliable tool for the evaluation of sperm respiratory efficiency | In this work we report a relatively simple and fast method for analysing oxygen consumption and therefore mitochondrial functionality, in individual human ejaculates. This oxygraphic method requires a low number of cells, is highly reproducible and linearly correlates with sperm concentration. Our results have shown that oxygen uptake by mitochondria of demembranated sperm cells from normozoospermic subjects is significantly stimulated by a large set of respiratory substrates and ADP. The respiratory control ratio (RCR) values indicate a good coupling between respiration and phosphorylation by sperm mitochondria and thus a well preserved integrity of the mitochondria themselves. Interestingly, whereas the rates of oxygen uptake, as expected, changed with different sperm concentrations, the RCR values remained constant, thus demonstrating a linear response of the assay. In asthenozoospermic subjects, however, a significant decrease in the sperm respiratory efficiency was found. The results obtained suggest that this method, besides its potential clinical application, could be useful for a deeper understanding of the biochemical properties of sperm mitochondria and their role in ATP production in human spermatozoa. | mitochondria | oxygen uptake | sperm motility | spermatozoa | mitochondria, oxygen uptake, sperm motility, spermatozoa | ||||||
| Oxygen electrode | Oxygraph | Journal of Molecular Catalysis A: Chemical | Jianshuai Mu | Harbin Institute of Technology | Academy of Fundamental and Interdisciplinary Sciences | China | 2013 | Co3O4 nanoparticles as an efficient catalase mimic: properties, mechanism and its electrocatalytic sensing application for hydrogen peroxide | Nanomaterial-based enzyme mimics have recently attracted considerable interest due to their easy preparation, low cost, high stability and so on. Herein Co3O4 nanoparticles (NPs) were used as a catalase mimic, catalyzing the decomposition of hydrogen peroxide to oxygen. The catalytic activity of Co3O4 NPs increased dramatically by adjusting the pH from acid to neutral and alkaline conditions. The catalytic activities and the mechanisms were investigated by using the procedures of thermodynamics, steady-state kinetics and hydroxyl radical detection. The activation energy of Co3O4 NPs was determined to be 43.3 KJ mol-1 which was similar to 42.8 KJ mol-1 of catalase. The catalytic behavior of Co3O4 NPs showed a typical Michaelis-Menten kinetics and good affinity to H2O2. The turnover number and specificity constant of Co3O4 NPs were very close to those of catalase. Based on the above results, Co3O4 NPs were an efficient catalase mimic. A catalytic mechanism was proposed where hydroxyl radicals took part in the catalytic recycles. Co3O4 NPs had better stability than natural catalase when they were exposed to solutions with different pH values and temperatures. As an efficient and stable catalase mimic, Co3O4 NPs were used as the amperometric sensor for the detection of hydrogen peroxide. | Co3O4 nanoparticles | catalase mimic | enzyme catalysis | biosensor | Co3O4 nanoparticles, catalase mimic, enzyme catalysis, biosensor | ||||||
| Oxygen electrode | Oxygraph | Biotechnology and Bioengineering | M. Famiglietti | ETH-Zurich | Institut fur polymere | Switzerland | 1992 | Photosynthetic Activity of Cyanobacteria in Water-in-Oil Microemulsions | The solubilization and the photosynthetic activity of cyanobacteria (Anabaena variabilis) in water-in-oil microemulsions consisting of (Tween85/Span80)/hexadecane/water is investigated. Transparent and stable solutions containing up to 108 cells/mL could be obtained. The physical state and stability of the cells in the microemulsion, as evidenced from optical and electron microscopy, is dependent upon the physical parameters of the system, and in particular on the hydrophilic-lypophilic balance (HLB) of the surfactant system. Conditions could be found, under which the cells in the microemulsion system display photosynthetic activity. This was judged by measuring polarographically the oxygen evolution and by studying the photosynthetic activity in the presence of specific inhibitors. | cyanobacteria | photosynthesis | organic solvent | microemulsion | cells | microbiology | cyanobacteria, photosynthesis, organic solvent, microemulsion, cells, microbiology | ||||
| Oxygen electrode | Oxygraph | Cancer Research | Rodrigue Rossignol | University of Oregon | Institute of Molecular Biology | USA | 2004 | Energy Substrate Modulates Mitochondrial Structure and Oxidative Capacity in Cancer Cells | Comparative analysis of cytoplasmic organelles in a variety of tumors relative to normal tissues generally reveals a strong diminution in mitochondrial content and in oxidative phosphorylation capacity. However, little is known about what triggers these modifications and whether or not they are physiologically reversible. We hypothesized that energy substrate availability could play an important role in this phenomenon. The physiological effects of a change in substrate availability were examined on a human cancer cell line (HeLa), focusing specifically on its ability to use glycolysis versus oxidative phosphorylation, and the effect that energy substrate type has on mitochondrial composition, structure, and function. Changes in oxidative phosphorylation were measured in vivo by a variety of techniques, including the use of two novel ratiometric green fluorescent protein biosensors, the expression level of oxidative phosphorylation and some glycolytic enzymes were determined by Western blot, mitochondrial DNA content was measured by real-time PCR, and mitochondrial morphology was monitored by both confocal and electron microscopy. Our data show that the defective mitochondrial system described in cancer cells can be dramatically improved by solely changing substrate availability and that HeLa cells can adapt their mitochondrial network structurally and functionally to derive energy by glutaminolysis only. This could also provide an explanation for the enhancement of oxidative phosphorylation capacity observed after tumor regression or removal. Our work demonstrates that the pleomorphic, highly dynamic structure of the mitochondrion can be remodeled to accommodate a change in oxidative phosphorylation activity. We compared our finding on HeLa cells with those for nontransformed fibroblasts to help distinguish the regulatory pathways. | |||||||||||
| Oxygen electrode | Oxygraph | Applied and Environmental Microbiology | Gennaro Agrimi | Universita degli Studi di Bari Aldo Moro | Dipartimento Farmaco Biologico | Italy | 2011 | Deletion or Overexpression of Mitochondrial NAD+ Carriers in Saccharomyces cerevisiae Alters Cellular NAD and ATP Contents and Affects Mitochondrial Metabolism and the Rate of Glycolysis | The modification of enzyme cofactor concentrations can be used as a method for both studying and engineering metabolism. We varied Saccharomyces cerevisiae mitochondrial NAD levels by altering expression of its specific mitochondrial carriers. Changes in mitochondrial NAD levels affected the overall cellular concentration of this coenzyme and the cellular metabolism. In batch culture, a strain with a severe NAD depletion in mitochondria succeeded in growing, albeit at a low rate, on fully respiratory media. Although the strain increased the efficiency of its oxidative phosphorylation, the ATP concentration was low. Under the same growth conditions, a strain with a mitochondrial NAD concentration higher than that of the wild type similarly displayed a low cellular ATP level, but its growth rate was not affected. In chemostat cultures, when cellular metabolism was fully respiratory, both mutants showed low biomass yields, indicative of impaired energetic efficiency. The two mutants increased their glycolytic fluxes, and as a consequence, the Crabtree effect was triggered at lower dilution rates. Strikingly, the mutants switched from a fully respiratory metabolism to a respirofermentative one at the same specific glucose flux as that of the wild type. This result seems to indicate that the specific glucose uptake rate and/or glycolytic flux should be considered one of the most important independent variables for establishing the long-term Crabtree effect. In cells growing under oxidative conditions, bioenergetic efficiency was affected by both low and high mitochondrial NAD availability, which suggests the existence of a critical mitochondrial NAD concentration in order to achieve optimal mitochondrial functionality. | |||||||||||
| Oxygen electrode | Oxygraph | Protein Expression & Purification | Karen R. Crozier | University of Wisconsin-Milwaukee | Department of Chemistry and Biochemistry | USA | 2006 | Heterologous expression and purification of kynurenine-3-monooxygenase from Pseudomonas fluorescens strain 17400 | Kynurenine 3-monooxygenase (KMO) is an NADPH-dependent flavoprotein hydroxylase that catalyzes the conversion of L-Kynurenine (L-Kyn) to 3-hydroxykynurenine (3OHKyn). The reaction is central to the tryptophan degradative pathway and takes place within microglial cells defining cellular concentrations of the N-methyl-D-aspatate (NMDA) receptor agonist quinolinate and antagonist kynurenate. The influence over the cellular concentrations of these NMDA receptor effectors makes KMO an attractive target for the treatment of ischemic stroke. Pseudomonas fluorescens str 17400, expresses five activities of tryptophan catabolism including that of KMO. The KMO gene from P. fluorescens was cloned into the pET-17b plasmid using incorporated NdeI and XhoI restriction sites. This construct yielded PfKMO to 20% of total cell protein after 12 h of expression at 22 C without induction by isopropyl-b-thiogalactopyranoside (IPTG). The enzyme could be readily purified using ammonium sulfate fractionation and ion exchange chromatography, resulting in pure KMO with a turnover number of 5.0 s 1. PfKMO activity was dependent on the reduction state of the enzyme. Preparation and storage benefited from the presence of a reductant such as dithiothreitol or b-mercaptoethanol. The loss of activity was found to be directly related to the oxidation of thiols as measured by dinitrothiobenzoate assay. Steady-state assays monitoring the consumption of dioxygen were used to measure apparent kinetic parameters and ligand perturbation of flavin fluorescence was used to determine a Kd value for both L-Kyn and the inhibitor m-nitrobenzoylalanine. PfKMO is offered as prototypical bacterial form of the enzyme to serve as a viable platform on which to base future KMO studies. | Kynurenine | Stroke | Purification | Expression | Pseudomonas | Monooxygenase | Hydroxylase | Flavin | FAD | Oxygenase | Kynurenine, Stroke, Purification, Expression, Pseudomonas, Monooxygenase, Hydroxylase, Flavin, FAD, Oxygenase |
| Oxygen electrode | Oxygraph | Journal of Visualized Experiments | Mary L. Garcia-Cazarin | University of Kentucky | Department of Physiology | USA | 2011 | Mitochondrial Isolation from Skeletal Muscle | Mitochondria are organelles controlling the life and death of the cell. They participate in key metabolic reactions, synthesize most of the ATP, and regulate a number of signaling cascades2,3. Past and current researchers have isolated mitochondria from rat and mice tissues such as liver, brain and heart4,5. In recent years, many researchers have focused on studying mitochondrial function from skeletal muscles. Here, we describe a method that we have used successfully for the isolation of mitochondria from skeletal muscles 6. Our procedure requires that all buffers and reagents are made fresh and need about 250-500 mg of skeletal muscle. We studied mitochondria isolated from rat and mouse gastrocnemius and diaphragm, and rat extraocular muscles. Mitochondrial protein concentration is measured with the Bradford assay. It is important that mitochondrial samples be kept ice-cold during preparation and that functional studies be performed within a relatively short time (~1 hr). Mitochondrial respiration is measured using polarography with a Clark-type electrode (Oxygraph system) at 37°C7. Calibration of the oxygen electrode is a key step in this protocol and it must be performed daily. Isolated mitochondria (150 μg) are added to 0.5 ml of experimental buffer (EB). State 2 respiration starts with addition of glutamate (5mM) and malate (2.5 mM). Then, adenosine diphosphate (ADP) (150 μM) is added to start state 3. Oligomycin (1 μM), an ATPase synthase blocker, is used to estimate state 4. Lastly, carbonyl cyanide p-[trifluoromethoxy]- phenyl-hydrazone (FCCP, 0.2 μM) is added to measurestate 5, or uncoupled respiration 6. The respiratory control ratio (RCR), the ratio of state 3 to state 4, is calculated after each experiment. An RCR ≥4 is considered as evidence of a viable mitochondria preparation. In summary, we present a method for the isolation of viable mitochondria from skeletal muscles that can be used in biochemical (e.g., enzyme activity, immunodetection, proteomics) and functional studies (mitochondrial respiration). | Video link: http://www.jove.com/video/2452/ | Video link: http://www.jove.com/video/2452/ | |||||||||
| Oxygen electrode | Oxygraph | Environmental Pollution | Laure Geoffroy | Universite de Reims Champagne-Ardenne | Laboratoire d’Eco-Toxicologie | France | 2004 | Comparison of different physiological parameter responses in Lemna minor and Scenedesmus obliquus exposed to herbicide flumioxazin | The sensitivity of different physiological parameters in Scenedesmus obliquus and Lemna minor exposed to herbicide (flumioxazin) was investigated to indicate the most convenient and sensitive parameter. To assess toxicity of flumioxazin, we used a panel of biomarkers: pigment contents, chlorophyll fluorescence parameters and antioxidative enzyme activities. Algae and duckweed were exposed to 48-h IC50 for growth rate. In L. minor, the sensitivity of the parameters was as follows: QN>Oxygen emission>ÞsPSII>QP>ÞPSII>CAT, GR>Pigment>APO>Growth. For S. obliquus, this ranking was as follows: CAT>Oxygen emission>QP>APO>GR>Pigment>ÞsPSII>Growth>ÞPSII>QN (from the greatest to the least sensitive). The results demonstrated that the observed toxicity is related not only to interspecific variations but also to the selected parameter. | Lemna minor | Scenedesmus obliquus | Herbicide | Oxidative stress | Chlorophyll fluorescence | Lemna minor, Scenedesmus obliquus, Herbicide, Oxidative stress, Chlorophyll fluorescence | |||||
| Chlorophyll fluorescence | FMS 1 | Environmental Pollution | Laure Geoffroy | Universite de Reims Champagne-Ardenne | Laboratoire d’Eco-Toxicologie | France | 2004 | Comparison of different physiological parameter responses in Lemna minor and Scenedesmus obliquus exposed to herbicide flumioxazin | The sensitivity of different physiological parameters in Scenedesmus obliquus and Lemna minor exposed to herbicide (flumioxazin) was investigated to indicate the most convenient and sensitive parameter. To assess toxicity of flumioxazin, we used a panel of biomarkers: pigment contents, chlorophyll fluorescence parameters and antioxidative enzyme activities. Algae and duckweed were exposed to 48-h IC50 for growth rate. In L. minor, the sensitivity of the parameters was as follows: QN>Oxygen emission>ÞsPSII>QP>ÞPSII>CAT, GR>Pigment>APO>Growth. For S. obliquus, this ranking was as follows: CAT>Oxygen emission>QP>APO>GR>Pigment>ÞsPSII>Growth>ÞPSII>QN (from the greatest to the least sensitive). The results demonstrated that the observed toxicity is related not only to interspecific variations but also to the selected parameter. | Lemna minor | Scenedesmus obliquus | Herbicide | Oxidative stress | Chlorophyll fluorescence | Lemna minor, Scenedesmus obliquus, Herbicide, Oxidative stress, Chlorophyll fluorescence | |||||
| Oxygen electrode | Oxygraph | The American Journal of Human Genetics | Christelle Tesson | Institut National de la Sante et de la Recherche Medicale | Unite 975 | France | 2012 | Alteration of Fatty-Acid-Metabolizing Enzymes Affects Mitochondrial Form and Function in Hereditary Spastic Paraplegia | Hereditary spastic paraplegia (HSP) is considered one of the most heterogeneous groups of neurological disorders, both clinically and genetically. The disease comprises pure and complex forms that clinically include slowly progressive lower-limb spasticity resulting from degeneration of the corticospinal tract. At least 48 loci accounting for these diseases have been mapped to date, and mutations have been identified in 22 genes, most of which play a role in intracellular trafficking. Here, we identified mutations in two functionally related genes (DDHD1 and CYP2U1) in individuals with autosomal-recessive forms of HSP by using either the classical positional cloning or a combination of whole-genome linkage mapping and next-generation sequencing. Interestingly, three subjects with CYP2U1 mutations presented with a thin corpus callosum, white-matter abnormalities, and/or calcification of the basal ganglia. These genes code for two enzymes involved in fatty-acid metabolism, and we have demonstrated in human cells that the HSP pathophysiology includes alteration of mitochondrial architecture and bioenergetics with increased oxidative stress. Our combined results focus attention on lipid metabolism as a critical HSP pathway with a deleterious impact on mitochondrial bioenergetic function. | |||||||||||
| Oxygen electrode | Oxygraph | Computer methods and programs in biomedicine | Audris Kopustinskas | Kaunas University of Technology | Faculty of Electrical and Control Engineering | Lithuania | 2006 | A user-friendly PC-based data acquisition and analysis system for respirometric investigations | We have developed an easy-to-use computer-based system for recording, displaying, storing and analyzing signals generated by Clark-type oxygen electrodes.Auser-friendly interface of Windows-based program BioMed significantly increases the productivity of investigations. It allows to process, control, present and archive the experimental data in real time. A 12- bit analog-to-digital-converter, analog and digital filters, a possibility to zoom the obtained respiratory curves and calculation of the respiration rates by a linear regression method increase the resolution of the estimated oxygen consumption rates. The newsystem enables to register even small changes, such as 3–5 ngatomsO/min, in respiration rates of biological objects—enzymes, mitochondria and permeabilized muscle fibers. The system has been developed and is regularly used for the respirometric investigations at the Laboratory of Biochemistry, Institute for Biomedical Research, Kaunas University of Medicine. | Bioenergetics | Respirometry | PC | Data acquisition | Data analysis | Bioenergetics, Respirometry, PC, Data acquisition, Data analysis | |||||
| Oxygen electrode | Oxygraph | Toxicology and Applied Pharmacology | Natalia D. Magnani | Universidad de Buenos Aires | Instituto of Bioquímica Medicina Molecular | Argentina | 2013 | Reactive oxygen species produced by NADPH oxidase and mitochondrial dysfunction in lung after an acute exposure to Residual Oil Fly Ashes | Reactive O2 species production triggered by particulate matter (PM) exposure is able to initiate oxidative damage mechanisms, which are postulated as responsible for increased morbidity along with the aggravation of respiratory diseases. The aim of this work was to quantitatively analyse the major sources of reactive O2 species involved in lung O2 metabolism after an acute exposure to Residual Oil Fly Ashes (ROFAs). Mice were intranasally instilled with a ROFA suspension (1.0 mg/kg body weight), and lung samples were analysed 1 h after instillation. Tissue O2 consumption and NADPH oxidase (Nox) activity were evaluated in tissue homogenates. Mitochondrial respiration, respiratory chain complexes activity, H2O2 and ATP production rates, mitochondrial membrane potential and oxidative damage markers were assessed in isolated mitochondria. ROFA exposure was found to be associated with 61% increased tissue O2 consumption, a 30% increase in Nox activity, a 33% increased state 3 mitochondrial O2 consumption and a mitochondrial complex II activity increased by 25%. During mitochondrial active respiration, mitochondrial depolarization and a 53% decreased ATP production rate were observed. Neither changes in H2O2 production rate, nor oxidative damage in isolated mitochondria were observed after the instillation. After an acute ROFA exposure, increase tissue O2 consumption may account for an augmented Nox activity, causing an increased O2 production. The mitochondrial function modifications found may prevent oxidative damage within the organelle. These findings provide new insights to the understanding of the mechanisms involving reactive O2 species production in the lung triggered by ROFA exposure. | Air pollution | Lung | Mitochondria | NADPH oxidase | Residual oil fly ash (ROFA) | Reactive O2 species | Air pollution, Lung, Mitochondria, NADPH oxidase, Residual oil fly ash (ROFA), Reactive O2 species | ||||
| Oxygen electrode | Oxygraph | Biochimica et Biophysica Acta | T. Marchini | University of Buenos Aires | Laboratory of Free Radical Biology | Argentina | 2013 | Impaired cardiac mitochondrial function and contractile reserve following an acute exposure to environmental particulate matter | Background: It has been suggested that mitochondrial function plays a central role in cardiovascular diseases associated with particulate matter inhalation. The aim of this study was to evaluate this hypothesis, with focus on cardiac O2 and energetic metabolism, and its impact over cardiac contractility. Methods: Swiss mice were intranasally instilled with either residual oil fly ash (ROFA) (1.0 mg/kg body weight) or saline solution. After 1, 3 or 5 h of exposure, O2 consumption was evaluated in heart tissue samples. Mitochondrial respiration, respiratory chain complexes activity, membrane potential and ATP content and production rate were assessed in isolated mitochondria. Cardiac contractile reserve was evaluated according to the Langendorff technique. Results: Three hours after ROFA exposure, tissue O2 consumption was significantly decreased by 35% (from 1180±70 to 760±60 ng-at O/min g tissue), as well as mitochondrial rest (state 4) and active (state 3) respiration, by 30 and 24%, respectively (control state 4: 88±5 ng-at O/min mg protein; state 3: 240±20 ng-at O/min mg protein). These findings were associated with decreased complex II activity, mitochondrial depolarization and deficient ATP production. Even though basal contractility was not modified (control: 75± 5 mm Hg), isolated perfused hearts failed to properly respond to isoproterenol in ROFA-exposed mice. Tissue O2 consumption rates positively correlated with cardiac contractile state in controls (r2=0.8271), but not in treated mice (r2=0.1396). General Significance: The present results show an impaired mitochondrial function associated with deficient cardiac contractility, which could represent an early cardiovascular alteration after the exposure to environmental particulate matter. | Air pollution | Heart | Mitochondrion | Particulate matter | Residual oil fly ash (ROFA) | Air pollution, Heart, Mitochondrion, Particulate matter, Residual oil fly ash (ROFA) | |||||
| Oxygen electrode | Oxygraph | Biochemical and Biophysical Research Communications | Kasturi L. Puranam | Duke University Medical Center | Deane Laboratory, Department of Medicine | USA | 2006 | Polyglutamine expansion inhibits respiration by increasing reactive oxygen species in isolated mitochondria | Huntington’s disease results from expansion of the polyglutamine (PolyQ) domain in the huntingtin protein. Although the cellular mechanism by which pathologic-length PolyQ protein causes neurodegeneration is unclear, mitochondria appear central in pathogenesis. We demonstrate in isolated mitochondria that pathologic-length PolyQ protein directly inhibits ADP-dependent (state 3) mitochondrial respiration. Inhibition of mitochondrial respiration by PolyQ protein is not due to reduction in the activities of electron transport chain complexes, mitochondrial ATP synthase, or the adenine nucleotide translocase. We show that pathologic-length PolyQ protein increases the production of reactive oxygen species in isolated mitochondria. Impairment of state 3 mitochondrial respiration by PolyQ protein is reversed by addition of the antioxidants N-acetyl-L-cysteine or cytochrome c. We propose a model in which pathologic-length PolyQ protein directly inhibits mitochondrial function by inducing oxidative stress. | Huntington’s disease | Polyglutamine | Mitochondria | Reactive oxygen species | Huntington’s disease, Polyglutamine, Mitochondria, Reactive oxygen species | ||||||
| Chlorophyll fluorescence | FMS 2 | Photosynthetica | H.H. Zhang | Northeast Agricultural University | College of Resources and Environment | China | 2020 | Effects of exogenous abscisic acid on the photosynthetic function and reactive oxygen species metabolism of tobacco leaves under drought stress | In this study, water solutions with different concentrations of abscisic acid (ABA) (10, 20, and 40 μmol L–1) were sprayed on leaves of drought-stressed tobacco seedlings. The results showed that under drought stress, both water content and photosynthetic carbon assimilation ability were reduced, PSII activity was also inhibited. Drought stress also led to the outbreak of reactive oxygen species in tobacco leaves and increased the degree of membrane peroxidation. However, spraying exogenous ABA significantly alleviated the damage caused by drought stress on the leaves. The potential mechanisms by which drought resistance in tobacco is improved by spraying exogenous ABA include: (1) regulation of the stomatal limitation of leaves, which is beneficial to water retention ability and can enhance photosynthetic function; (2) reduction of the energy pressure of the PSII reaction center by increasing nonphotochemical quenching (NPQ); and (3) effective reduction of the production of reactive oxygen species in the leaves and reducing the degree of membrane peroxidation. | chlorophyll fluorescence | oxidative damage | photoinhibition. | chlorophyll fluorescence, oxidative damage, photoinhibition. | |||||||
| Chlorophyll fluorescence | Handy PEA | Photosynthetica | H.H. Zhang | Northeast Agricultural University | College of Resources and Environment | China | 2020 | Effects of exogenous abscisic acid on the photosynthetic function and reactive oxygen species metabolism of tobacco leaves under drought stress | In this study, water solutions with different concentrations of abscisic acid (ABA) (10, 20, and 40 μmol L–1) were sprayed on leaves of drought-stressed tobacco seedlings. The results showed that under drought stress, both water content and photosynthetic carbon assimilation ability were reduced, PSII activity was also inhibited. Drought stress also led to the outbreak of reactive oxygen species in tobacco leaves and increased the degree of membrane peroxidation. However, spraying exogenous ABA significantly alleviated the damage caused by drought stress on the leaves. The potential mechanisms by which drought resistance in tobacco is improved by spraying exogenous ABA include: (1) regulation of the stomatal limitation of leaves, which is beneficial to water retention ability and can enhance photosynthetic function; (2) reduction of the energy pressure of the PSII reaction center by increasing nonphotochemical quenching (NPQ); and (3) effective reduction of the production of reactive oxygen species in the leaves and reducing the degree of membrane peroxidation. | chlorophyll fluorescence | oxidative damage | photoinhibition. | chlorophyll fluorescence, oxidative damage, photoinhibition. | |||||||
| Oxygen electrode | Oxytherm | MDPI: Pathogens | Ingrid Škodová-Sveráková | Czech Academy of Sciences | Institute of Parasitology | Czech Republic | 2020 | Catalase and Ascorbate Peroxidase in Euglenozoan Protists | In this work, we studied the biochemical properties and evolutionary histories of catalase (CAT) and ascorbate peroxidase (APX), two central enzymes of reactive oxygen species detoxification, across the highly diverse clade Eugenozoa. This clade encompasses free-living phototrophic and heterotrophic flagellates, as well as obligate parasites of insects, vertebrates, and plants. We present evidence of several independent acquisitions of CAT by horizontal gene transfers and evolutionary novelties associated with the APX presence. We posit that Euglenozoa recruit these detoxifying enzymes for specific molecular tasks, such as photosynthesis in euglenids and membrane-bound peroxidase activity in kinetoplastids and some diplonemids. | Euglenozoa | ascorbate peroxidase | catalase | enzymatic activity | phylogeny | Euglenozoa, ascorbate peroxidase, catalase, enzymatic activity, phylogeny | |||||
| Chlorophyll fluorescence | Handy PEA | Acta Physiologiae Plantarum | Caroline Igansi Duarte | Universidade Federal do Rio Grande | Brazil | 2020 | Seed germination, growth and chlorophyll a fluorescence in young plants of Allophylus edulis in different periods of flooding | The distribution of woody species in flooded environments depends on the duration of stress as well as seed germination strategies and plant morphophysiological adaptations. Allophylus edulis is a tree that occurs in temporarily or permanently flooded areas in several countries of South America. In this paper, we evaluate seed germination, growth parameters, photosynthetic pigment contents and chlorophyll a fluorescence in young plants to understand the tolerance of the specie to flood events. The evaluations were performed in non-flooded (NFL) and flooded (FL) plants in a temporal scale that included short (up to 30 days) and long (up to 90 days) flood periods. A short flooding (15 days) may favor germination but maintaining stress for 60 days makes the seeds unviable. Although 71.4% of the FL plants survived up to 90 days of flooding, injuries such as chlorosis and foliar abscission appeared. An increase in stem height and diameter was only observed in NFL plants; whereas, FL plants showed a growth inhibition. At 90 days, NFL and FL plants presented total dry mass of 18.35 ± 1.57 g and 1.93 ± 0.62 g, respectively. The photosynthetic performance indexes indicated acclimatization of the plants on the third day of flooding, but the stress induced a progressive decline in the parameters, signaling damages to the photosystem II. Both seeds and young plants of A. edulis tolerate short periods of flooding, but prolonged floods make the seeds unfeasible and damages the photosynthetic apparatus, leading to death of the plants. | Stress | Flood acclimatization | Hypoxia | Sapindaceae | Recalcitrant seed | Stress, Flood acclimatization, Hypoxia, Sapindaceae, Recalcitrant seed | ||||||
| Chlorophyll fluorescence | Handy PEA | Plant Ecology | Hanna Chang | Korea University | Department of Environmental Science and Ecological Engineering | South Korea | 2020 | Experimental warming and drought treatments reduce physiological activities and increase mortality of Pinus koraiensis seedlings | This study was conducted to investigate physiological responses and mortality of P. koraiensis seedlings under warming and drought treatments. In May 2016, 90 P. koraiensis seedlings (aged 2 years) were planted in each plot (n = 20), and exposed to a combination of + 3 °C warming and − 30% drought, with 5 replicates. Net photosynthetic rate (A), stomatal conductance (gs), transpiration (E), and maximal photochemical efficiency of photosystem II (Fv/Fm) were measured from April 2017 to December 2018. Seedling mortality was measured eight times during the study period at irregular intervals. A, gs, and E decreased by − 21.99%, − 34.58%, and − 33.6% under the warming treatment, and by − 5.82%, − 11.03%, and − 8.56% under the drought treatment, respectively, in response to decreasing soil water content and increasing soil and leaf temperature. There was no significant difference in the overall Fv/Fm by the warming and drought treatments. The long-term reduction in photosynthesis by the warming treatment might cause carbon starvation, resulting in a 7.43-fold increase in seedling mortality. Moreover, under the drought treatment, seedling mortality was unaffected since its effects on A were occasional and small as compared to the warming treatment. Due to the unusually high temperature in summer of 2018, leaf temperature was 38.28 °C and seedlings were exposed to temperature above 45 °C for 10.7 h under the warming treatment. Fv/Fm in August 2018 decreased sharply by − 11.79% and seedling mortality increased by 15.31-fold during summer, under the warming treatment. Thus, leaf damage by severe heat stress may have triggered a rapid increase in seedling mortality. | Chlorophyll fluorescence | Drought | Gas exchange | Korean pine | Mortality | Warming | Chlorophyll fluorescence, Drought, Gas exchange, Korean pine, Mortality, Warming | ||||
| Chlorophyll fluorescence | Handy PEA | Physiology and Molecular Biology of Plants | Sunita Kataria | Devi Ahilya University | School of Biochemistry | India | 2020 | Role of nitric oxide and reactive oxygen species in static magnetic field pre-treatment induced tolerance to ambient UV-B stress in soybean | The experiments were conducted for the estimation of the mitigating effect of the static magnetic field (SMF of 200 mT for 1 h) treatment on soybean under ambient UV-B stress. The SMF treated (MT) and untreated (UT) seeds were grown inside iron cages covered with polyester filters for the purpose to filter UV-A + B (< 400 nm) and UV-B (< 300 nm) radiations, polythene filter control (FC) transparent for UV (280-400 nm), and open controls (OC) were without any filters. Our results indicated that specific leaf weight, efficiency of PS II, activity of carbonic anhydrase (CA) and nitrogenase (NRA), nucleic acid and protein content, nitric oxide (NO) and yield were significantly decreased in plants of untreated seeds under UV-B stress. SMF treatment to the soybean seeds was observed to mitigate the adverse effect of ambient UV-B with a significant enhancement in above-measured parameters in plants when compared with plants of untreated seeds grown under OC/FC conditions. Chlorophyll a fluorescence transition curve (OJIP-curve) from SMF treated and UV excluded plants has shown a higher fluorescence yield especially for I–P phase as compared to the plants grown in ambient UV-B stress. Reduction in the level of superoxide anion radicle (O⋅−2), hydrogen peroxide (H2O2), malondialdehyde (MDA) and proline content with a remarkable increase in DNA, RNA, protein and NO content, increased photosynthetic efficiency and nitrogen fixation in the leaves of soybean suggested the ameliorating effect of SMF pre-treatment against ambient UV-B induced damage. Consequently, SMF-pretreatment increased the tolerance of soybean seedlings to ambient UV-B stress as compared to the untreated seeds. The increase in carbon and nitrogen fixation ability due to SMF pre-treatment and the omission of solar UV radiation impact can be a direction for the purpose to improve the crop yield. Evaluation of the consequences of SMF treated seeds under ambient UV-B stress, and the plants from untreated seeds under solar UV exclusion indicated parallelism among the two effects. | Abiotic stress | Chl a fluorescence | Carbonic anhydrase | Nitrogenase | UV-B | Specific leaf weight | Yield | Abiotic stress, Chl a fluorescence, Carbonic anhydrase, Nitrogenase, UV-B, Specific leaf weight, Yield | |||
| Chlorophyll fluorescence | Handy PEA | Environmental Science and Pollution Research | Gintarė Sujetovienė | Vytautas Magnus University | Department of Environmental Sciences | Lithuania | 2020 | Physiological response of the bioindicator Ramalina farinacea in relation to atmospheric deposition in an urban environment | Urban air pollution is one of the most important environmental problems. Lichens are good bioindicators in air pollution studies because of their dependence on the atmospheric deposition for nutrition. The present study focused on the effects of urbanization on the composition of atmospheric deposition inputs and physiological parameters of transplanted epiphytic lichen Ramalina farinacea. The status of lichens responded to urban pollutants related to vehicle and industrial activity (NO3−, Ca2+, Mg2+, NO2, PM10). The content of chlorophyll and FV/FM were positively related to the amount of precipitation (mm) and the Normalized Difference Vegetation Index (NDVI). The increase in lipid peroxidation and electrolyte conductivity, indicating damage to the cell membrane, was found in lichens transplanted to the urban environment. The high variability in electrolyte conductivity indicated that cell membrane injuries were characteristics of the investigated study area. | Atmospheric deposition | Biomonitoring | Urbanization | Lichen | Ramalina farinacea | Physiological stress | Atmospheric deposition, Biomonitoring, Urbanization, Lichen, Ramalina farinacea, Physiological stress | ||||
| Chlorophyll fluorescence | Pocket PEA | Crop Science | Zhou Li | Sichuan Agricultural University | Department of Grassland Science | China | 2020 | Myo‐inositol enhances drought tolerance in creeping bentgrass through alteration of osmotic adjustment, photosynthesis, and antioxidant defense | Myo‐inositol (MI) regulates stress adaptation in plants. The objective of this study was to investigate effects of foliar MI application on improving drought tolerance associated with osmotic adjustment (OA), photosynthesis, and antioxidant defense in creeping bentgrass (Agrostis stolonifera L.). Both MI‐pretreated (1 mM) and untreated plants were subjected to drought stress or well‐watered condition for 12 days in growth chambers. Results showed that exogenous MI application protected plants from drought damage by improving OA and water use efficiency, and these contributed to better water status in creeping bentgrass. Interestingly, the foliar spray of MI promoted the accumulation of water soluble carbohydrates, but decreased drought‐induced free proline in leaves. The MI‐pretreated plants exhibited significantly greater chlorophyll (Chl) content, photochemical efficiency (Fv/Fm), performance index on absorption basis (PIABS), and net photosynthetic rate (Pn) than untreated plants in response to drought stress. Foliar application of MI decreased superoxide anion radical, hydrogen peroxide, malondialdehyde content, and electrolyte leakage, but increased superoxide dismutase (SOD), catalase (CAT), peroxide (POD), and ascorbate peroxidase (APX) activities and gene expression in leaves under drought stress. This study indicates that MI‐induced drought tolerance was involved in the maintenance of better water relation associated with increases in OA and WUE, the decline in Chl loss for photosynthetic maintenance, and improvement in antioxidant enzymes activity and gene expression contributing to less oxidative damage under drought stress. It is worth further investigating stress‐defensive proteins and metabolites induced by MI in turfgrass or other plant species under drought stress or other abiotic stresses. | |||||||||||
| Chlorophyll fluorescence | FMS 2 | Aquaculture Research | Yongfu Li | Chinese Academy of Sciences | CAS Key Laboratory of Experimental Marine Biology | China | 2020 | Analysis of light absorption and photosynthetic activity by Isochrysis galbana under different light qualities | The effect of light qualities, for example white light (WL), blue light (BL), red light (RL) and green light (GL), respectively, provided by the LEDs on the growth, pigment content, light absorption and chlorophyll fluorescence parameters of Isochrysis galbana strain IOAC724S was measured. The growth rate of algae exposed to GL was not significantly different from that of WL, but was significantly higher than that of blue light (BL) or red light (RL). These four light colours were all efficiently absorbed by algal cells, with an absorption rate up to 92%–93%. The light absorbed by pigments contributes only part of the light absorbed by cells, ranging from 8.3% (at RL) to 59.7% (at BL). Among the monochromatic light, the highest light absorption was obtained in cells cultivated at BL, but the photochemical reaction was lowered. No positive effect of monochromatic RL was found. Cells cultivated at BL and RL were, respectively, restricted by down‐regulated photosynthetic efficiency and sufficient light absorption; meanwhile, GL showed a dramatic increase in photosynthetic efficiency, associated with a light absorption close to that for cells exposed to WL (both at 30.6%), suggesting that GL promotes the photosynthesis of I. galbana by balancing the light absorption and utilization. | electron transport rate | Isochrysis galbana | light absorption | light quality | light utilization | electron transport rate, Isochrysis galbana, light absorption, light quality, light utilization | |||||
| Chlorophyll fluorescence | Handy PEA | Aquaculture Research | Yongfu Li | Chinese Academy of Sciences | CAS Key Laboratory of Experimental Marine Biology | China | 2020 | Analysis of light absorption and photosynthetic activity by Isochrysis galbana under different light qualities | The effect of light qualities, for example white light (WL), blue light (BL), red light (RL) and green light (GL), respectively, provided by the LEDs on the growth, pigment content, light absorption and chlorophyll fluorescence parameters of Isochrysis galbana strain IOAC724S was measured. The growth rate of algae exposed to GL was not significantly different from that of WL, but was significantly higher than that of blue light (BL) or red light (RL). These four light colours were all efficiently absorbed by algal cells, with an absorption rate up to 92%–93%. The light absorbed by pigments contributes only part of the light absorbed by cells, ranging from 8.3% (at RL) to 59.7% (at BL). Among the monochromatic light, the highest light absorption was obtained in cells cultivated at BL, but the photochemical reaction was lowered. No positive effect of monochromatic RL was found. Cells cultivated at BL and RL were, respectively, restricted by down‐regulated photosynthetic efficiency and sufficient light absorption; meanwhile, GL showed a dramatic increase in photosynthetic efficiency, associated with a light absorption close to that for cells exposed to WL (both at 30.6%), suggesting that GL promotes the photosynthesis of I. galbana by balancing the light absorption and utilization. | electron transport rate | Isochrysis galbana | light absorption | light quality | light utilization | electron transport rate, Isochrysis galbana, light absorption, light quality, light utilization | |||||
| Oxygen electrode | S1 | Philosophical Transactions of the Royal Society B | Livia Merendino | Université Paris-Saclay | Institute of Plant Sciences | France | 2020 | Retrograde signals from mitochondria reprogramme skoto-morphogenesis in Arabidopsis thaliana via alternative oxidase 1a | The early steps in germination and development of angiosperm seedlings often occur in the dark, inducing a special developmental programme called skoto-morphogenesis. Under these conditions photosynthesis cannot work and all energetic requirements must be fulfilled by mitochondrial metabolization of storage energies. Here, we report the physiological impact of mitochondrial dysfunctions on the skoto-morphogenic programme by using the Arabidopsis rpoTmp mutant. This mutant is defective in the T7-phage-type organellar RNA polymerase shared by plastids and mitochondria. Lack of this enzyme causes a mitochondrial dysfunction resulting in a strongly reduced mitochondrial respiratory chain and a compensatory upregulation of the alternative-oxidase (AOX)-dependent respiration. Surprisingly, the mutant exhibits a triple-response-like phenotype with a twisted apical hook and a shortened hypocotyl. Highly similar phenotypes were detected in other respiration mutants (rug3 and atphb3) and in WT seedlings treated with the respiration inhibitor KCN. Further genetic and molecular data suggest that the observed skoto-morphogenic alterations are specifically dependent on the activity of the AOX1a enzyme. Microarray analyses indicated that a retrograde signal from mitochondria activates the ANAC017-dependent pathway which controls the activation of AOX1A transcription. In sum, our analysis identifies AOX as a functional link that couples the formation of a triple-response-like phenotype to mitochondrial dysfunction. | Arabidopsis | mitochondrial respiration | alternative oxidase | retrograde signal | organellar RPOTmp RNA polymerase | skoto-morphogenesis | Arabidopsis, mitochondrial respiration, alternative oxidase, retrograde signal, organellar RPOTmp RNA polymerase, skoto-morphogenesis | ||||
| Oxygen electrode | S1 | Philosophical Transactions of the Royal Society B | Aleksandra Adamowicz-Skrzypkowska | University of Wroclaw | Faculty of Biotechnology | Poland | 2020 | Joint inhibition of mitochondrial complex IV and alternative oxidase by genetic or chemical means represses chloroplast transcription in Arabidopsis | Changes in the functional state of mitochondria have profound effects on other cellular compartments. Genome-wide expression analysis of Arabidopsisrps10 mutants with an RNAi-silenced expression of mitoribosomal S10 protein has revealed extensive transcriptional reprogramming. A meta-analysis comparing expression datasets of 25 mitochondrial perturbations showed a high similarity of the aox1a:rpoTmp mutant, which is defective in the alternative oxidase (AOX1a) and dual-targeted mitochondrial and plastid RNA polymerase (RPOTmp), to rps10. Both rps10 and aox1a:rpoTmp showed a significantly decreased electron flux through both the cytochrome and the alternative respiratory pathways, and a markedly decreased the expression of nuclear-encoded components of the chloroplast transcription machinery. In line with this, a decreased level of plastid transcripts was observed in rps10 and aox1a:rpoTmp, which was reflected in a reduced rate of chloroplast transcription. Chemical treatment of wild-type seedlings with respiratory inhibitors showed that only simultaneous and direct inhibition of complex IV and AOX activity decreased the level of plastid transcripts. Taken together, both chemical and genetic studies show that the limitation of the activity of two mitochondrial terminal oxidases, complex IV and AOX, negatively impacts chloroplast transcription. Salicylic acid and oxygen are discussed as putative mediators of the signalling pathway between mitochondria, nucleus and chloroplasts. | alternative oxidase | complex IV | chloroplast transcription | NEP and PEP | Arabidopsis thaliana | low oxygen signalling | alternative oxidase, complex IV, chloroplast transcription, NEP and PEP, Arabidopsis thaliana, low oxygen signalling | ||||
| Oxygen electrode | S1 | Cell Reports | Alba Timón-Gómez | University of Miami Miller School of Medicine | Department of Neurology | USA | 2020 | Distinct Roles of Mitochondrial HIGD1A and HIGD2A in Respiratory Complex and Supercomplex Biogenesis | The mitochondrial respiratory chain enzymes are organized as individual complexes and supercomplexes, whose biogenesis remains to be fully understood. To disclose the role of the human Hypoxia Inducible Gene Domain family proteins HIGD1A and HIGD2A in these processes, we generate and characterize HIGD-knockout (KO) cell lines. We show that HIGD2A controls and coordinates the modular assembly of isolated and supercomplexed complex IV (CIV) by acting on the COX3 assembly module. In contrast, HIGD1A regulates CIII and CIII-containing supercomplex biogenesis by supporting the incorporation of UQCRFS1. HIGD1A also clusters with COX4-1 and COX5A CIV subunits and, when overexpressed, suppresses the CIV biogenesis defect of HIGD2A-KO cells. We conclude that HIGD1A and HIGD2A have both independent and overlapping functions in the biogenesis of respiratory complexes and supercomplexes. Our data illuminate the existence of multiple pathways to assemble these structures by dynamic HIGD-mediated CIV biogenesis, potentially to adapt to changing environmental and nutritional conditions. | |||||||||||
| Chlorophyll fluorescence | Handy PEA | Journal of Environmental Science and Health | Hansol Kim | Sangmyung University | Department of Biotechnology | South Korea | 2020 | The herbicide alachlor severely affects photosystem function and photosynthetic gene expression in the marine dinoflagellate Prorocentrum minimum | Alachlor is one of the most widely used herbicides and can remain in agricultural soils and wastewater. The toxicity of alachlor to marine life has been rarely studied; therefore, we evaluated the physiological and transcriptional responses in the marine dinoflagellate Prorocentrum minimum. The herbicide led to considerable decreases in P. minimum cell numbers and pigment contents. The EC50 was determined to be 0.373 mg/L. Photosynthesis efficiency and chlorophyll autofluorescence dramatically decreased with increasing alachlor dose and exposure time. Real-time PCR analysis showed that the photosynthesis-related genes PmpsbA, PmatpB, and PmrbcL were induced the most by alachlor; the transcriptional level of each gene varied with time. PmrbcL expression increased after 30 min of alachlor treatment, whereas PmatpB and PmpsbA increased after 24 h. The PmpsbA expression level was highest (5.0 times compared to control) after 6 h of alachlor treatment. There was no significant change in PmpsaA expression with varying treatment time or concentration. Additionally, there was no notable change in the expression of antioxidant genes PmGST and PmKatG, or in ROS accumulation. These suggest that alachlor may affect microalgal photosystem function, with little oxidative stress, causing severe physiological damage to the cells, and even cell death. | Prorocentrum minimum | alachlor | physiological parameters | photosynthesis genes | antioxidant genes | transcriptional response | Prorocentrum minimum, alachlor, physiological parameters, photosynthesis genes, antioxidant genes, transcriptional response | ||||
| Chlorophyll fluorescence | Handy PEA | Biocatalysis and Agricultural Biotechnology | Ramin Lotfi | Agricultural Research Education & Extension Organization | Dryland Agricultural Research Institute | Iran | 2020 | Salicylic acid regulates photosynthetic electron transfer and stomatal conductance of mung bean (Vigna radiata L.) under salinity stress | The role of salicylic acid (0, 1 and 1.5 mM) on photosynthetic electron transfer chain of mung-bean plants grown under salt stress (0, 3, 6 and 9 dS/m2) was studied using chlorophyll a fluorescence (ChlF) measurements. Results indicated that accumulation of K+ content decreased but, Na+ content increased with increasing salt stress. SA-treated plants had more K+ and less Na+ content compared with the non-SA treated plants. Application of SA, especially with 1 mM, increased the I–P step of the OJIP transient curve of fluorescence. Salt stress decreased gs, CCI, FV, FM, SM and PIabs in plants. However, the time taken to reach FM (TFM) increased with increasing salt stress. Application of different concentrations of SA significantly improved gs, CCI, FV, SM, and PIabs of plants. Photosynthetic efficiency of plants improved as a result of SA application via decreasing Fo and increasing FV/FM, FV/Fo, SM/TFM and Area under both saline and non-saline conditions. Accumulation of Na + had negative, but K+ had a positive correlation with gs, CCI and most of the chlorophyll a fluorescence parameters (except, Fo and TFM). A positive correlation was found between gS and CCI with PIabs. This research indicated that low gs under saline condition seems to cause losses in PSII efficiency, but the application of SA with 1 mM concentration is the best treatment for the alleviation of salt stress injuries on PSII activity of mung bean plants. | Fluorescence | Mung bean | Photosynthesis | Stomatal conductance | Salt stress | Salicylic acid | Fluorescence, Mung bean, Photosynthesis, Stomatal conductance, Salt stress, Salicylic acid | ||||
| Chlorophyll fluorescence | Handy PEA | Plant Physiology and Biochemistry | Fevzi Elbasan | Selcuk University | Department of Biotechnology | Turkey | 2020 | Rare-earth element scandium improves stomatal regulation and enhances salt and drought stress tolerance by up-regulating antioxidant responses of Oryza sativa | Oryza sativa L. cv. Gönen grown in hydroponic culture was treated with scandium (Sc; 25 and 50 μM) alone or in combination with salt (100 mM NaCl) and/or drought (5% PEG-6000). Stress caused a decrease in growth (RGR), water content (RWC), osmotic potential (ΨΠ), chlorophyll fluorescence (Fv/Fm) and potential photochemical efficiency (Fv/Fo). Sc application prevented the decreases of these parameters. Sc also alleviated the changes on gas exchange parameters (carbon assimilation rate (A), stomatal conductance (gs), intercellular CO2 concentrations (Ci), transpiration rate (E) and stomatal limitation (Ls)). Stress caused no increase in superoxide dismutase (SOD) activity. After induvial applied NaCl or PEG, catalase (CAT) and ascorbate peroxidase (APX) showed an enhancement in activation and tried to scavenge of hydrogen peroxide (H2O2). On the other hand, in plants with the combination form of NaCl and PEG, only CAT activity was induced. Sc applications to NaCl-treated rice led to an increase of SOD, APX, glutathione reductase (GR), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR) as well as peroxidase (POX). Sc under NaCl could be maintained both ascorbate (AsA) and glutathione (GSH) regeneration. Despite of induction of MDHAR and DHAR under Sc plus PEG, Sc did not maintain AsA redox state because of no induction in APX activity. However, GSH pool could be regenerated by induction in DHAR and GR in this group. Sc application (especially for 25 μM) in rice exposed to NaCl + PEG resulted an enhancement in APX and MDHAR and so Sc could be partially provided AsA regeneration. Since no increases in DHAR and GR were observed, GSH pool was reduced. Due to this activation of antioxidant enzymes, stress-induced H2O2 and TBARS content (lipid peroxidation) significantly decreased in rice with Sc applications. Sc in plants with stress also increased the transcript levels of OsCDPK7 and OsBG1 related to stomatal movement and signaling pathway. Consequently, Sc protected the rice plants by minimizing disturbances caused by NaCl or PEG exposure via the AsA-GSH redox-based systems. | Antioxidant enzymes | Drought stress | Rare earth elements | Salinity | Scandium | Antioxidant enzymes, Drought stress, Rare earth elements, Salinity, Scandium | |||||
| Chlorophyll fluorescence | Handy PEA | Scientia Horticulturae | Fatemeh Shahsavandi | Shiraz University | Department of Horticultural Science | Iran | 2020 | Effects of bicarbonate induced iron chlorosis on photosynthesis apparatus in grapevine | High bicarbonate concentration in alkaline and calcareous soils as well as irrigation water is the most important inducing factor of Fe chlorosis in plant species. The purpose of this study was to investigate the effects of Fe chlorosis induced by sodium bicarbonate (15 (Moderate bicarbonate, MB) and 30 (High bicarbonate, HB) mM) as well as using different Fe sources (FeEDTA(FE) and FeSO4 7 H2O (FS)) on photosynthesis apparatus in four grapevine cultivars including ‘Yaghouti’, ‘Rotabi’, ‘Flame Seedless’ and ‘Thompson Seedless’. In this study factorial experimental was conducted based on a completely randomized design with 6 replications. Results indicated that, bicarbonate treatment (15 and 30 mM) and Fe deficiency (FD) decreased leaf chlorophyll index in all cultivars regardless of Fe sources. Results also indicated that FV/FM and FV/FO significantly decreased in Thompson Seedless and Rotabi cultivars under Fe deficient treatment but were not affected in Yaghouti and Flame Seedless cultivars. The negative effects of high bicarbonate concentration (30 mM) on maximum quantum yield and FV/FO were more than those of Fe deficient and moderate bicarbonate concentration treatments. Results of the specific fluxes per RC showed that an increase occurred in ABS/RC, TR0/RC and DI0/RC in Yaghouti and Flame Seedless cultivars under high bicarbonate concentration in both Fe sources, whilst for the ET0/RC a decrease was observed. Results indicated that the PIABS significantly decreased under high bicarbonate concentration in all cultivars and both Fe sources. Generally, cultivars showed different responses to bicarbonate and Fe deficiency, Thompson Seedless and Rotabi cultivars showed higher tolerance to bicarbonate application and Yaghouti and Flame Seedless cultivars were more tolerance in Fe deficiency. | Bicarbonate | Chlorophyll florescence | Performance index | Chlorophyll content | Bicarbonate, Chlorophyll florescence, Performance index, Chlorophyll content | ||||||
| Chlorophyll fluorescence | Pocket PEA | Journal of Agricultural Science and Technology | Silindile Precious Miya | University of KwaZulu-Natal | School of Agricultural | South Africa | 2020 | Seed Scarification Improves Physiological Growth and Development of Bambara Groundnut (Vigna subterranea) Depending on Seed Coat Colour | This study was conducted to investigate the effect of scarification on bambara groundnut (Vigna subterranea) physiological growth and development and crop phenology. Bambara groundnut landrace seeds used in this study were characterized by seed coat colour (cream, light brown and brown). Seed scarification treatments were mechanical (sand paper) and chemical (sulphuric acid) scarification, while seeds that were not scarified served as a control. A completely randomized design with three replications was used. The parameters that were assessed were time to emergence, final emergence percentage, leaf number, chlorophyll content index (CCI), canopy diameter, plant height, chlorophyll fluorescence (Fv/Fm), photosynthetic performance index (Pi), time to flowering and time to senescence. CCI, leaf number and plant height were significantly (p < 0.05) influenced by seed coat colour, seed scarification treatments and their interaction thereof. Seed scarification treatment had a significant effect on CCI, leaf number and plant height. Generally, seed scarification improved plant overall performance than the control. Chemical scarification presented superior performance of bambara groundnut growth and development. Light brown seeds produced plants with superior overall performance, having superior emergence, CCI, leaf number, and early flowering and senescence. Light brown seeds were followed by cream seeds in terms of superiority of plant performance, having produced plants with superior canopy diameter, plant height and Pi. Therefore, bambara groundnut farmers and researchers can successfully use scarification to improve its physiological growth and attain earlier phenological stages, hence maturity. At the same time, light brown seeds should be selected for cultivation to give the best plant performance. | Canopy cover | chlorophyll | plant development | plant growth | photosynthesis | Canopy cover, chlorophyll, plant development, plant growth, photosynthesis | |||||
| Chlorophyll fluorescence | Handy PEA | MDPI: Forests | Barbara Mariotti | Università di Firenze | Dipartimento di Scienze e Tecnologie Agrarie | Italy | 2020 | Coconut Coir as a Sustainable Nursery Growing Media for Seedling Production of the Ecologically Diverse Quercus Species | Peat, a non-sustainable resource, is still predominately used in forest nurseries. Coconut coir might provide an alternative, renewable, and reliable growing media but few studies have evaluated this media type in forest nurseries. We assessed the influence of pure coir, in combination with various fertilization regimes, on the growth and physiology of three ecologically diverse Quercus species seedlings (Q. robur, Q. pubescens, and Q. ilex) during nursery cultivation. Seedlings were grown using peat and pure coir in combination with three fertilization treatments (standard, K-enriched, and P-enriched). Data were collected for: (1) growth and physiological traits; (2) detailed above- and below-ground morphological traits by destructive analysis; and (3) NPK content in leaves, shoot and roots, and in the growing media, following cultivation. Peat and coir in combination with the various fertilization treatments affected above- and below-ground morphology and, to a lesser extent, the physiological traits of Quercus seedlings. Large effects of the substrate occurred for most morphological variables, with peat being more effective than coir in all studied species. Fertilization also produced significant differences. The effect of K-enriched fertilization on plant growth was clear across the three species and the two growing media. P-enriched fertilization in peat was the only combination that promoted a higher amount of this element in the tissues at the end of cultivation. Despite their smaller size, seedlings produced in coir were compatible with standard Quercus forest stocktype size, and showed a proportionally higher root system development and fibrosity. Our results suggest that coir can be used as an alternative substrate to grow Quercus species seedlings, and that fertilization can offset coir deficiencies in chemical properties. As several functional traits drive planting performance under varying environmental conditions. according to the Target Plant Concept, coir might thus serve as an acceptable material for seedling cultivation in some cases. | forest nursery stock | coconut fiber | peat | seedling morphology | seedling physiology | substrate | forest nursery stock, coconut fiber, peat, seedling morphology, seedling physiology, substrate | ||||
| Oxygen electrode | S1 | Photosynthesis Research | Yoshifumi Ueno | Kobe University | Graduate School of Science | Japan | 2020 | Photoprotection mechanisms under different CO2 regimes during photosynthesis in a green alga Chlorella variabilis | Oxygenic photosynthesis converts light energy into chemical energy via electron transport and assimilates CO2 in the Calvin–Benson cycle with the chemical energy. Thus, high light and low CO2 conditions induce the accumulation of electrons in the photosynthetic electron transport system, resulting in the formation of reactive oxygen species. To prevent the accumulation of electrons, oxygenic photosynthetic organisms have developed photoprotection mechanisms, including non-photochemical quenching (NPQ) and alternative electron flow (AEF). There are diverse molecular mechanisms underlying NPQ and AEF, and the corresponding molecular actors have been identified and characterized using a model green alga Chlamydomonas reinhardtii. In contrast, detailed information about the photoprotection mechanisms is lacking for other green algal species. In the current study, we examined the photoprotection mechanisms responsive to CO2 in the green alga Chlorella variabilis by combining the analyses of pulse-amplitude-modulated fluorescence, O2 evolution, and the steady-state and time-resolved fluorescence spectra. Under the CO2-limited condition, ΔpH-dependent NPQ occurred in photosystems I and II. Moreover, O2-dependent AEF was also induced. Under the CO2-limited condition with carbon supplementation, NPQ was relaxed and light-harvesting chlorophyll-protein complex II was isolated from both photosystems. In C. variabilis, the O2-dependent AEF and the mechanisms that instantly convert the light-harvesting functions of both photosystems may be important for maintaining efficient photosynthetic activities under various CO2 conditions. | Alternative electron flow | Excitation energy transfer | Green alga | Light harvesting | Non-photochemical quenching | Time-resolved fluorescence spectroscopy | Alternative electron flow, Excitation energy transfer, Green alga, Light harvesting, Non-photochemical quenching, Time-resolved fluorescence spectroscopy | ||||
| Oxygen electrode | S1 | Materials Science | Li Wang | Wuhan University of Technology | State Key Laboratory of Advanced Technology for Materials Synthesis and Processing | China | 2020 | Single-cell yolk-shell nNanoencapsulation for long-term viability with size-dependent permeability and molecular recognition | Like nanomaterials, bacteria have been unknowingly used for centuries. They hold significant economic potential for fuel and medicinal compound production. Their full exploitation, however, is impeded by low biological activity and stability in industrial reactors. Though cellular encapsulation addresses these limitations, cell survival is usually compromised due to shell-to-cell contacts and low permeability. Here, we report ordered packing of silica nanocolloids with organized, uniform, and tunable nanoporosities for single cyanobacterium nanoencapsulation using protamine as an electrostatic template. A space between the capsule shell and the cell is created by controlled internalization of protamine, resulting in a highly ordered porous shell-void-cell structure formation. These unique yolk-shell nanostructures provide long-term cell viability with superior photosynthetic activities and resistance in harsh environments. In addition, engineering the colloidal packing allows tunable shell-pore diameter for size-dependent permeability and introduction of new functionalities for specific molecular recognition. Our strategy could significantly enhance the activity and stability of cyanobacteria for various nanobiotechnological applications. | cell surface engineering | protein internalization | ordered colloidal packing | high photosynthetic ability | harsh condition resistance | thiol-functionalization | cell surface engineering, protein internalization, ordered colloidal packing, high photosynthetic ability, harsh condition resistance, thiol-functionalization | ||||
| Chlorophyll fluorescence | Handy PEA | Chemosphere | Zhenxia Li | Henan Institute of Science and Technology | College of Horticulture and Landscape | China | 2020 | Physiological response of cucumber (Cucumis sativus L.) leaves to polystyrene nanoplastics pollution | Microplastics pollution in farmlands has become a major concern. However, few studies have assessed the effects of microplastics on higher plants. In this study, we investigated the influence of polystyrene nanoplastics (PSNPs, 50 mg L−1), with four different particle sizes (100, 300, 500, and 700 nm), on the physiological and biochemical indexes of cucumber leaves. The biomass of cucumber plants significantly decreased after exposure to 300 nm PSNPs. Similarly, the chlorophyll a, chlorophyll b, soluble sugar, carotenoid, and proline content, as well as the fluorescence of cucumber leaves were significantly reduced by 100 nm PSNPs. Malondialdehyde, proline, peroxidase gene expression and enzyme activity, and hydrogen peroxide content significantly increased in cucumber leaves exposed to 700 nm PSNPs. In addition, increasing PSNPs particle size led to decreased relative expression levels and activities of the major antioxidant enzymes superoxide dismutase and catalase, while vitamin C and soluble protein content significantly increased. Overall, our results indicated that PSNPs affect the photosynthetic, antioxidant, and sugar metabolism systems of cucumber leaves, with the latter clearly affecting the total biomass of cucumber plants. The benzene ring resulting from the degradation of PSNPs in cucumber leaves may be the main factor affecting chlorophyll metabolism and sugar metabolism. Our findings provide a scientific basis for the risk assessment of PSNPs exposure in soil-plant systems. | Nanoplastics | Polystyrene | Cucumber | Physiological indexes | Biochemical indexes | Nanoplastics, Polystyrene, Cucumber, Physiological indexes, Biochemical indexes | |||||
| Chlorophyll fluorescence | Handy PEA | Ornamental Horticulture | Elizangela Rodrigues Santos | Federal University of Espírito Santo (UFES) | Department of Agrarian and Biological Sciences | Brazil | 2020 | Morphophysiological responses of Billbergia zebrina Lindl. (Bromeliaceae) in function of types and concentrations of carbohydrates during conventional in vitro culture | When propagated in vitro, explants receive all the nutrients needed for their growth, including carbohydrates, from the culture medium. However, it is not well understood how the type and concentration of carbohydrates can affect the functioning of the photosynthetic apparatus (particularly photosystem II) of these plants. The aim was to assess the morphophysiological responses of Billbergia zebrina plants in function of sources and concentrations of carbohydrates during in vitro culture. Side shoots of plants previously established in vitro were individualized and transferred to a culture medium containing fructose, glucose or sucrose in four concentrations (0, 15, 30 or 45 g L-1). After growth for 55 days, the chlorophyll a fluorescence transient, leaf anatomy and growth were analyzed. The concentration and type of carbohydrate employed during in vitro culture did not decrease the photosynthetic apparatus performance. However, concentrations above 30 g L-1 led to anatomical modifications, revealing some degree of stress suffered by the plants. When grown in concentrations of 15 and 30 g L-1, irrespective of the carbohydrate used, the plants presented greater stomatal density. The supplementation of the culture medium with monosaccharides caused alterations in the development of the xylem vessels, such as increased number and diameter, allowing adjustment to the microenvironmental conditions. The in vitro conditions influenced the photosynthetic and anatomical responses of plants. The concentration interval from 15 to 30 g L-1 sucrose had a better effect by not causing large changes in the performance of the photosynthetic apparatus and anatomy of plants. | bromeliad | chlorophyll a fluorescence | plant anatomy | plant physiology | plant tissue culture | bromeliad, chlorophyll a fluorescence, plant anatomy, plant physiology, plant tissue culture | |||||
| Chlorophyll fluorescence | Handy PEA | Journal of Plant Physiology | Maria Pilarska | Polish Academy of Sciences | The Franciszek Górski Institute of Plant Physiology | Poland | 2020 | Differences in the functioning of photosynthetic electron transport between metallicolous and non-metallicolous populations of the pseudometallophyte Viola tricolor | The objective of this study was to assess the effect of metalliferous conditions on the functioning of photosynthetic electron transport in waste heap populations of a pseudometallophyte, Viola tricolor L. Measurements of chlorophyll a fluorescence and the absorbance changes at 830 nm enabled a non-invasive assessment of photosynthetic apparatus performance. This was complemented by the evaluation of the chlorophyllcontent. Low temperature chlorophyll fluorescence emission spectra were also recorded. Based on the OJIP test performed in situ, we demonstrated a disturbed condition of photosystem II (PSII) in three metalliferous populations in comparison with a non-metallicolous one. The combined effects of elevated concentrations of zinc, cadmium and lead in soil resulted in the decline of some parameters describing the efficiency and electron flow through PSII. The differences between waste heap populations seemed to be partly correlated with the concentration of heavy metals in the soil. The characteristic of electron transport at photosystem I (PSI) in the light-adapted state revealed increased values of PSI donor-side limitation (YND) and a declined PSI quantum efficiency (YI). It was also demonstrated that the waste heap conditions negatively affect the total chlorophyll content in leaves and led to an increased ratio of fluorescence emission at 77 K (F730/F685). The obtained data indicate that, regardless of the high adaptation of metallicolous populations, photosynthetic electron transport is hampered in V. tricolor plants at metal polluted sites. | chlorophyll fluorescence | heavy metals | OJIP test | photosynthetic activity | chlorophyll fluorescence, heavy metals, OJIP test, photosynthetic activity | ||||||
| Oxygen electrode | Chlorolab 2 | Bioresource Technology Reports | Luna Viggiano de Alvarenga | Universidade Federal de Viçosa | Departamento de Biologia Vegetal | Brazil | 2020 | Physiological responses to light intensity and photoperiod of the halotolerant cyanobacterium Desmonostoc salinum CCM-UFV059 | The growth and physiology of Desmonostoc salinum CCM-UFV059 were analyzed regarding different light regimes and in presence of NaCl (100 mM). Similar growth patterns were observed regardless the treatments and cells under 70 μmol m−2·s−1 (16:8 h light/dark) displayed the highest growth rate. Biomass was higher (~1.60 g·L−1) under continuous light. Higher amounts of proteins were observed in 16:8-photoperiod. Cyanophycin and phycobiliproteins contents were lower under 70 μmol m−2·s−1 (16:8). Carbohydrates were invariant considering the same light intensity. Neutral lipids showed higher levels under 70 μmol m−2·s−1 (16:8). D. salinum also produced considerable amounts of biomass in medium with salt. Our results provide novel insights into how distinct light regimes interfere with the cyanobacterial metabolism. More important, the ability of CCM-UFV059 to sustain photosynthesis and to produce biomass under moderate saline conditions and long-day conditions highlights the possibility of its cultivation in brackish waters in different regions. | Biomass production | Biotechnology | Light regime | Metabolism | Storage compounds | Stress responses | Biomass production, Biotechnology, Light regime, Metabolism, Storage compounds, Stress responses | ||||
| Chlorophyll fluorescence | FMS 2 | Protoplasma | Bili Cao | Shandong Agricultural University | College of Horticulture Science and Engineering | China | 2020 | Effect of a mist culture system on photosynthesis and nitrogen metabolism in ginger | To evaluate the transition from traditional shading cultivation to mist cultivation, a field experiment was carried out. The results demonstrated that compared with traditional shading, the mist treatment significantly reduced leaf temperature. Likewise, the higher transpiration rate also contributes to reducing leaf temperature and protects ginger from heat stress in summer. Moreover, a higher instantaneous efficiency of water use suggested that water lost via transpiration was beneficial under a mist culture system. The higher instantaneous efficiency of water use in the mist treatment was caused mainly by the higher net photosynthetic rate, which is further reflected by the higher rhizome yield of ginger under the mist culture system. Instead of lowering the temperature by lowering photon flux density, mist treatment does not seriously reduce the photon flux density while reducing the temperature of the blade. Hence, the net photosynthetic rate in the shading treatment is significantly lower than that in the mist treatment, although the maximal quantum yield of photosystem II and the actual photochemical efficiency of photosystem II in ginger in the shading treatment were significantly higher than those in the mist treatment. Lower superoxide anion, hydrogen peroxide, and malondialdehyde contents were also found after mist treatment. Lower ammonium avoids the potential risk of ammonium toxicity and is based on higher nitrate reductase, glutamine synthetase, and glutamate synthase activity but lower glutamate dehydrogenase activity. Therefore, the mist cultivation system improved the physiological characteristics and yields of ginger and can be suggested as an alternative, sustainable, and cleaner cultivation measure. | Ginger | Mist cultivation | Shading film cultivation | Physiological characteristics | Yield | Ginger, Mist cultivation, Shading film cultivation, Physiological characteristics, Yield | |||||
| Oxygen electrode | Oxytherm | Esha Gauba | University of Texas at Dallas | Department of Biological Sciences | USA | 2020 | Modulation of OSCP mitigates mitochondrial and synaptic deficits in a mouse model of Alzheimer’s pathology | Oligomycin-sensitivity conferring protein (OSCP) is a critical subunit of mitochondrial F1Fo ATP synthase. OSCP dysfunction has been observed in Alzheimer’s disease (AD) brains and a mouse model with AD-like brain amyloidosis (5xFAD mice). However, whether OSCP dysfunction constitutes a key mitochondrial defect contributing to synaptic injury in AD-related conditions has not been comprehensively investigated. | Oligomycin sensitivity-conferring protein | mitochondrial F1Fo ATP synthase | synaptic injury | amyloid beta | Alzheimer’s disease | Oligomycin sensitivity-conferring protein, mitochondrial F1Fo ATP synthase, synaptic injury, amyloid beta, Alzheimer’s disease | ||||||
| Oxygen electrode | Oxygraph+ | Russian Journal of Plant Physiology | E. N. Ikkonen | Russian Academy of Sciences | Institute of Biology | Russia | 2020 | Response of Winter Wheat Seedlings Respiration to Long-Term Cold Exposure and Short-Term Daily Temperature Drops | The effects of a long-term (6-day) exposure to low positive temperature (4°С, LT treatment) and short-term (3 h per a day for 6 days) daily temperature drops to 4°С (DROP treatment) on leaf respiration in winter wheat (Triticum aestivum L., var. Moskovskaya 39) were studied under controlled conditions. In the case of the LT treatment, the respiration rate in the darkness (Rd) increased by 36%, while the DROP treatment only resulted in a tendency to such an increase. The influence of both DROP and LT treatments on the respiration rate in the light (Rl) and temperature sensitivity of Rd and Rl was insignificant. In contrast to the DROP treatment, the LT treatment increased the level of light-induced inhibition of plant respiration. In both LT- and DROP-treated plants, the rate of gross photosynthesis (Ag) measured at 12°С increased by 23 and 54%, respectively, as compared to the control plants. The DROP treatment did not affect the Rd/Ag and Rl/Ag ratios in plant leaves. The Rd/Ag value in LT-treated plants measured at 22°С was higher than in control plants, while the Rl/Ag value measured at 12°С was lower than in the control. The DROP treatment did not affect the sensitivity of respiration to salicylhydroxamic acid (SHAM), an inhibitor of the alternative respiratory pathway. The LT treatment increased the share of a SHAM-sensitive respiration in the total respiration of plant leaves by 25% on average, which indirectly indicates the activation of an alternative pathway of the electron transfer in the respiratory chain. Thus, a long-term continuous exposure of winter wheat seedlings to low positive temperatures provided a modifying effect on respiration manifested via changes in the respiratory rate, activity of the SHAM-sensitive respiration, and the ratio between respiration and gross photosynthesis. In the case of a short-term daily exposure to low temperature high respiration stability was observed. | Triticum aestivum | winter wheat | respiration | low positive temperature | Triticum aestivum, winter wheat, respiration, low positive temperature | ||||||
| Chlorophyll fluorescence | Handy PEA | Marine Pollution Bulletin | Palliyath Sruthi | University of Calicut | Plant Physiology and Biochemistry Division | India | 2020 | High NaCl tolerance potential of Bruguiera cylindrica (L.) Blume compromised by mild CuSO4 concentration as evidenced by unique physiochemical features | Differential response of Bruguiera cylindrica to individual (CuSO4) and combined (CuSO4 NaCl) effect was evaluated. The plantlets were treated with control, 0.15 mM CuSO4, 400 mM NaCl and 0.15 mM CuSO4 + 400 mM NaCl. Under combined stress, higher accumulation of Cu in the roots indicate that the roots are the primary site of Cu accumulation and thus the plant perform as an excluder and photosynthetic efficiency reduced drastically and significant enhancement in the superoxide and hydroxyl free radicals which increase membrane lipid peroxidation, leading to cellular damage and destruction. As evidenced from SEM-EDXMA, increase in Cu and Na+ levels in xylem and pith regions of leaf and stem and the presence of deeply stained structures, denoting the probable formation of complex containing the metal. Increased CaOx crystal forming cells (crystal idioblasts) reveals the regulation of bioaccumulated Cu and Na+ by complexing with CaOx. Thus the study suggested that, 400 mM NaCl and 0.15 mM CuSO4 treatments does not have negative impact on plant growth, the NaCl tolerance potential compromised in the presence of mild CuSO4 concentration during combined stress. | Bruguiera cylindrica | Combined stress | Crystal idioblast | Electrolytic leakage | MDA | Membrane stability index | Oxidative damage | Bruguiera cylindrica, Combined stress, Crystal idioblast, Electrolytic leakage, MDA, Membrane stability index, Oxidative damage | |||
| Oxygen electrode | Oxygraph | Marine Pollution Bulletin | Palliyath Sruthi | University of Calicut | Plant Physiology and Biochemistry Division | India | 2020 | High NaCl tolerance potential of Bruguiera cylindrica (L.) Blume compromised by mild CuSO4 concentration as evidenced by unique physiochemical features | Differential response of Bruguiera cylindrica to individual (CuSO4) and combined (CuSO4 NaCl) effect was evaluated. The plantlets were treated with control, 0.15 mM CuSO4, 400 mM NaCl and 0.15 mM CuSO4 + 400 mM NaCl. Under combined stress, higher accumulation of Cu in the roots indicate that the roots are the primary site of Cu accumulation and thus the plant perform as an excluder and photosynthetic efficiency reduced drastically and significant enhancement in the superoxide and hydroxyl free radicals which increase membrane lipid peroxidation, leading to cellular damage and destruction. As evidenced from SEM-EDXMA, increase in Cu and Na+ levels in xylem and pith regions of leaf and stem and the presence of deeply stained structures, denoting the probable formation of complex containing the metal. Increased CaOx crystal forming cells (crystal idioblasts) reveals the regulation of bioaccumulated Cu and Na+ by complexing with CaOx. Thus the study suggested that, 400 mM NaCl and 0.15 mM CuSO4 treatments does not have negative impact on plant growth, the NaCl tolerance potential compromised in the presence of mild CuSO4 concentration during combined stress. | Bruguiera cylindrica | Combined stress | Crystal idioblast | Electrolytic leakage | MDA | Membrane stability index | Oxidative damage | Bruguiera cylindrica, Combined stress, Crystal idioblast, Electrolytic leakage, MDA, Membrane stability index, Oxidative damage | |||
| Oxygen electrode | S1 | MDPI: Life | Vasily V. Terentyev | Russian Academy of Sciences | Institute of Basic Biological Problems | Russia | 2020 | The Main Structural and Functional Characteristics of Photosystem-II-Enriched Membranes Isolated from Wild Type and cia3 Mutant Chlamydomonas reinhardtii | Photosystem II (PSII)-enriched membranes retain the original PSII architecture in contrast to PSII cores or PSII supercomplexes, which are usually isolated from Chlamydomonas reinhardtii. Here, we present data that fully characterize the structural and functional properties of PSII complexes in isolated PSII-enriched membranes from C. reinhardtii. The preparations were isolated from wild-type (WT) and CAH3-deficient mutant cia3 as the influence of CAH3 on the PSII function was previously proposed. Based on the equal chlorophyll content, the PSII-enriched membranes from WT and cia3 have the same amount of reaction centers (RCs), cytochrome b559, subunits of the water-oxidizing complex,Mnions, and carotenes. They di er in the ratio of other carotenoids, the parts of low/intermediate redox forms of cytochrome b559, and the composition of outer light-harvesting complexes. The preparations had 40% more chlorophyll molecules per RC compared to higher plants. Functionally, PSII-enriched membranes from WT and cia3 show the same photosynthetic activity at optimal pH 6.5. However, the preparations from cia3 contained more closed RCs even at pH 6.5 and showed more pronounced suppression of PSII photosynthetic activity at shift pH up to 7.0, established in the lumen of dark-adapted cells. Nevertheless, the PSII photosynthetic capacities remained the same. | Chlamydomonas reinhardtii | photosystem II | CAH3 | chlorophyll | carotenoids | cytochrome b559 | OJIP-kinetic | Chlamydomonas reinhardtii, photosystem II, CAH3, chlorophyll, carotenoids, cytochrome b559, OJIP-kinetic | |||
| Chlorophyll fluorescence | FMS 2 | MDPI: Agronomy | Tommaso Frioni | Università Cattolica del Sacro Cuore | Department of Sustainable Crop Production | Italy | 2020 | Grafting cv. Grechetto Gentile Vines to New M4 Rootstock Improves Leaf Gas Exchange and Water Status as Compared to Commercial 1103P Rootstock | M4 is a relatively new rootstock that was selected for increased resilience of vineyards across hot regions where meteorological drought is often coupled to water scarcity. However, M4 has thus far been tested only against water-stress sensitive rootstocks. Against this backdrop, the aim of the present work is to examine the water status and gas exchange performances of vines grafted to M4 in comparison to those of vines grafted to a commercial stock that is drought-tolerant, 1103 Paulsen (1103P), under a progressive water deficit followed by re-watering. This study was undertaken on Grechetto Gentile, a cultivar that is renowned for its rather conservative water use (near-isohydric behavior). While fifty percent of both grafts were fully irrigated (WW), the remaining underwent progressive water stress by means of suspending irrigation (WS). Soil and leaf water status, as well as leaf gas exchanges, along with chlorophyll fluorescence, were followed daily from 1 day pre-stress (DOY 176) until re-watering (DOY 184). Final leaf area per vine, divided in main and lateral contribution, was also assessed. While 1103P grafted vines manifested higher water use under WW conditions, progressive stress evidenced a faster water depletion by 1103P, which also maintained slightly more negative midday leaf water potential (Yleaf) as compared to M4 grafted plants. Daily gas exchange readings, as well as diurnal assessment performed at the peak of stress (DOY 183), also showed increased leaf assimilation rates (A) and water use efficiency (WUE) in vines grafted on M4, which were also less susceptible to photosynthetic downregulation. Dynamic of stomatal closure targeted at 90% reduction of leaf stomatal conductance showed a similar behavior among rootstocks since the above threshold was reached by both at Yleaf of about 1.11 MPa. The same fractional reduction in leaf A was reached by vines grafted on M4 at a Yleaf of 1.28 MPa vs. 1.10 MPa measured in 1103P, meaning that using M4 as a rootstock will postpone full stomatal closure. While mechanisms involved in improved CO2 uptake in M4-grafted vines under moderate-to-severe stress are still unclear, our data support the hypothesis that M4 might outscore the performance of a commercial drought-tolerant genotype (1103P) and can be profitably used as a tool to improve the resilience of vines to summer drought. | transpiration | drought | water stress | Vitis vinifera L. | stomatal closure | rootstock | water use efficiency | Cites Handy PEA but is actually FMS 2 | transpiration, drought, water stress, Vitis vinifera L., stomatal closure, rootstock, water use efficiency, Cites Handy PEA but is actually FMS 2 | ||
| Oxygen electrode | S1 | Bioresource Technology | Ramachandran Sivaramakrishnan | Chulalongkorn University | Laboratory of Cyanobacterial Biotechnology | Thailand | 2020 | Response of Scenedesmus sp. to microwave treatment: Enhancement of lipid, exopolysaccharide and biomass production | The present study focuses on the use of microwave irradiation to improve the production of lipid, exopolysaccharide and biomass in the microalgae Scenedesmus sp. Microwave treatment conditions such as microwave power, duty cycle % and time was optimized to increase the biomass and lipid content of Scenedesmus sp. Microwave power 100 W, duty cycle 40 %, and 2 min treatment time led to a substantial improvement in the biomass and lipid content. Due to the simultaneous improvement in both the biomass and lipid content, the total lipid production was improved from 0.76 (microwave untreated) to 1.42 g/L (microwave treated) (12 days grown cells). In addition, with biomass and lipid content, microwave treatment also enhanced the production of exopolysaccharides (EPS) up to 2.3-folds. Furthermore, biodiesel properties were improved to some extent after the microwave treatment. Microwave irradiation is a promising physical treatment method for microalgae to improve total lipid production. | biomass | exopolysaccharides | lipids | microalgae | microwave | oxidative stress | biomass, exopolysaccharides, lipids, microalgae, microwave, oxidative stress | ||||
| Oxygen electrode | S1 | European Journal of Pharmacology | Glauber Rudá Feitoza Braz | Federal University of Pernambuco | Neuropsychiatry and Behavior Science Graduate Program | Brazil | 2020 | Fluoxetine administration in juvenile overfed rats improves hypothalamic mitochondrial respiration and REDOX status and induces mitochondrial biogenesis transcriptional expression | Nutritional imbalance in early life may disrupt the hypothalamic control of energy homeostasis and increase the risk of metabolic disease. The hypothalamic serotonin (5-hydroxytryptamine; 5-HT) system based in the hypothalamus plays an important role in the homeostatic control of energy balance, however the mechanisms underlying the regulation of energy metabolism by 5-HT remain poorly described. Several crucial mitochondrial functions are altered by mitochondrial stress. Adaptations to this stress include changes in mitochondrial multiplication (i.e, mitochondrial biogenesis). Due to the scarcity of evidence regarding the effects of serotonin reuptake inhibitors (SSRI) such as fluoxetine (FLX) on mitochondrial function, we sought to investigate the potential contribution of FLX on changes in mitochondrial function and biogenesis occurring in overfed rats. Using a neonatal overfeeding model, male Wistar rats were divided into 4 groups between 39 to 59 days of age based on nutrition and FLX administration: normofed + vehicle (NV), normofed + FLX (NF), overfed + vehicle (OV) and overfed + FLX (OF). We found that neonatal overfeeding impaired mitochondrial respiration and increased oxidative stress biomarkers in the hypothalamus. FLX administration in overfed rats reestablished mitochondrial oxygen consumption, increased mitochondrial uncoupling protein 2 (Ucp2) expression, reduced total reactive species (RS) production and oxidative stress biomarkers, and up-regulated mitochondrial biogenesis-related genes. Taken together our results suggest that FLX administration in overfed rats improves mitochondrial respiratory chain activity and oxidative balance and increases the transcription of genes employed in mitochondrial biogenesis favoring mitochondrial energy efficiency in response to early nutritional imbalance. | Electron transport chain complex proteins | Overfeeding | Oxidative phosphorylation | Oxidative stress | RT-PCR | Serotonin reuptake inhibitor | Electron transport chain complex proteins, Overfeeding, Oxidative phosphorylation, Oxidative stress, RT-PCR, Serotonin reuptake inhibitor | ||||
| Chlorophyll fluorescence | Handy PEA | Revista Caatinga | AMANDA DOS SANTOS SOUZA | Universidade Federal Rural do Rio de Janeiro | Department of Plant Science | Brazil | 2020 | LEACHING AND CARRYOVER FOR SAFRINHA CORN OF THE HERBICIDES IMAZAPYR + IMAZAPIC IN SOIL UNDER DIFFERENT WATER CONDITIONS | Soil moisture can alter the transport and permanence of pre-emergent herbicides. The objective of this work was to evaluate the influence of water availability in the soil on the leaching of a commercial mixture of the herbicides imazapyr + imazapic, as well as the carryover effect of this herbicide in corn planted in succession to soybean. The experiment was carried out in leaching columns in a randomized block design with 4 replications. A 3x3x2 factorial scheme was used, with factor A being the irrigation (130%, 100% and 70% of field capacity (CC)), factor B the doses of the commercial mixture of the herbicides imazapyr + imazapic (0.00+ 0.00; 52.5 + 17.5 and 105 + 35 g ha-1) and factor C at soil depth (0-0.3 m and 0.3-0.6 m). Soybean sowing was performed at the top of the columns and immediately after herbicide mixture was applied. After 120 days the columns were opened, generating two sections, where corn (Zea mays) and the other watermelon (Citrullus lanatus) were sown as a bioindicator of herbicide residue. The fluorescence parameters of chlorophyll a at 15 and 30 days after germination (DAG) and shoot dry matter accumulation at 30 DAG were evaluated. There was greater retention of the herbicide imazapyr + imazapic at a depth of 0-0.3m at 70% CC condition and leaching at a depth of 0.3-0.6m at 130% CC condition, with a reduction in the mass accumulation of watermelon plants. The herbicide has a carryover potential for corn cultivation in soils maintained at 70% CC. | Cultivation in succession | Imidazolinones | Persistence | Residual | Cultivation in succession, Imidazolinones, Persistence, Residual | ||||||
| Chlorophyll fluorescence | FMS 1 | Water, Air, & Soil Pollution | Maria Vera Jesus Da Costa | Goa University | Department of Botany | India | 2020 | Copper Oxide Nanoparticle and Copper (II) Ion Exposure in Oryza sativa Reveals Two Different Mechanisms of Toxicity | The effects of CuO NPs and bulk Cu at 0–1000 mg L−1 on the growth, photosynthesis and biochemical parameters were investigated in 30-day-old rice plants grown hydroponically. ICP-OES measurements showed that CuO NPs released ≤ 1 mg L−1 of Cu2+ ions compared with ≤ 81 mg L−1 by bulk Cu at their highest concentration. Both treatments showed that growth, photo-phosphorylation and carbon dioxide assimilation declined considerably. Bulk particles caused oxidative stress whereas NP showed no such effect. Electromicrographs showed that CuO NPs accumulated in chloroplasts resulting in destacking and distortions of thylakoid membranes while bulk Cu showed no such behaviour. Results suggest that NP affected the growth by accumulation in non-ionic form in chloroplasts causing damage to thylakoid membrane without oxidative damage, whereas the bulk Cu affected the growth by causing oxidative damage as a result of release of Cu2+ ions without affecting the ultrastructure of the chloroplasts. | Dissolution | Thylakoids | MDA | Lipid peroxidation | Photosynthesis | Dissolution, Thylakoids, MDA, Lipid peroxidation, Photosynthesis | |||||
| Chlorophyll fluorescence | FMS 2 | Mycological Progress | Katalin Veres | MTA Centre for Ecological Research | Institute of Ecology and Botany | Hungary | 2020 | The bright and shaded side of duneland life: the photosynthetic response of lichens to seasonal changes is species-specific | Terricolous lichens are relevant associates of biological soil crusts in arid and semiarid environments. Dunes are ecosystems of high conservation interest, because of their unique, vulnerable and threatened features. The function of lichens is affected by the changing seasons and different microhabitat conditions. At the same time, inland dunes are less investigated areas from the terricolous lichens point of view. We explored the effect of seasonal variation and different micro-environmental conditions (aspect) on the metabolic activity of five terricolous lichen species, representing various growth forms, in temperate semiarid grasslands. Populations of Cladonia foliacea, C. furcata, C. pyxidata group, Diploschistes muscorum and Thalloidima physaroides were investigated. Thalli sampled from the south-west and north-east facing microhabitats were studied by chlorophyll fluorescence analysis for 2 years. The present study aims to understand how changing climate (during the year) and aspect affect photosynthetic activity and photoprotection. Microclimatic data were also continuously recorded to reveal the background of the difference between microhabitat types. As a result, the air temperature, photosynthetically active radiation, soil temperature and vapour pressure deficit were significantly higher on south-west than on north-east facing microsites, where relative humidity and water content of soil proved to be considerably higher. Higher photosynthetic activity, as well as a higher level of photoprotection, was detected in lichens from north-east-oriented microsites compared with south-west populations. In addition, the difference between sun and shade populations varied seasonally. Since a species-specific response to both aspect and season was detected, we propose to investigate more than one species of different growth forms, to reveal the response of lichens to the changing environment in space and time. | Terricolous lichens | Aspect | Microclimate | Photosynthetic activity | Photoprotection | Temperate semiarid sandy grassland | Terricolous lichens, Aspect, Microclimate, Photosynthetic activity, Photoprotection, Temperate semiarid sandy grassland | ||||
| Chlorophyll fluorescence | Handy PEA | Ecotoxicology and Environmental Safety | Eloy Navarro-León | University of Granada | Department of Plant Physiology | Spain | 2020 | Assaying the use of sodium thiosulphate as a biostimulant and its effect on cadmium accumulation and tolerance in Brassica oleracea plants | An optimal uptake of mineral elements is crucial to ensure both crop yield and quality. The use of biostimulants is taking relevance to improve the nutrition of crops. Sulphur (S) is one of the elements with great potential within biostimulants. Furthermore, soil contamination by heavy metals such as cadmium (Cd) has become a serious environmental problem. Different studies have suggested the use of thiosulphate (TS) as a biostimulant and to increase the phytoremediation capacity of plants. Therefore, in the present study, we use a crop plant with high S requirements such as Brassica oleracea, to test whether TS serves as a biostimulant and whether affects Cd accumulation and tolerance. B. oleracea plants were grown with two different TS doses (2 mM and 4 mM), under Cd toxicity, and with the combination of Cd toxicity and both TS doses. Parameters of biomass, mineral elements accumulation, and stress tolerance were analyzed. The results showed that TS reduced biomass of B. oleracea plants. The application of 2 mM TS increased Cd accumulation whereas the 4 mM dose reduced it. On the other hand, TS incremented micronutrient accumulation on plants subjected to Cd toxicity and increased Zn contents. Besides, the application of 2 mM to Cd-stressed plants enhanced photosynthesis performance and reduced oxidative stress. Finally, TS increased the antioxidant capacity of B. oleracea plants. Briefly, although TS can not be used as a biostimulant it could be used for Cd phytoremediation purposes and to enhance Zn accumulation in B. oleracea plants. | Antioxidant | Cabbage | Cadmium | Mineral nutrients | Phytoremediation | Zinc | Antioxidant, Cabbage, Cadmium, Mineral nutrients, Phytoremediation, Zinc | ||||
| Chlorophyll fluorescence | Handy PEA | Algal Research | M. Carneiro | University of Porto | Laboratory for Process Engineering | Portugal | 2020 | Effect of temperature on growth, photosynthesis and biochemical composition of Nannochloropsis oceanica, grown outdoors in tubular photobioreactors | Since temperature is an important factor affecting microalgal growth, photosynthetic rate and biomass composition, this study has accordingly focused on its effects on biomass yield and nighttime biomass loss, as well as photochemical changes, using Nannochloropsis oceanica as model species, grown in two outdoor 50-L tubular photobioreactors (PBR). In two independent trials, cultures were subjected to a diurnal light:dark cycle, under a constant temperature of 28 °C and, on the second trial, at 18 °C. Changes in culture performance were assessed by measuring growth, lipid and fatty acid composition of the biomass in both morning and evening. Our results revealed that N. oceanica shows a wide temperature tolerance with relevant nighttime biomass loss, that decreased at lower temperatures, at the expenses of its daily productivity. Fluorescence measurements revealed reversible damage to photosystem II in cells growing in the PBR under optimal thermal conditions, whereas microalgae grown at suboptimal ones exhibited an overall lower photosynthetic activity. Lipids were partially consumed overnight to support cell division and provide maintenance energy. Eicosapentaenoic acid (EPA) catabolism reached a maximum after the dark period, as opposed to their saturated counterparts; whereas lower temperatures led to higher EPA content which reached the maximum in the morning. These findings are relevant for the production of Nannochloropsis at industrial scale. | Nannochloropsis | Temperature | Photosynthesis | Respiration | Night biomass loss | Chlorophyll fluorescence | Nannochloropsis, Temperature, Photosynthesis, Respiration, Night biomass loss, Chlorophyll fluorescence | ||||
| Oxygen electrode | Chlorolab 3 | Algal Research | M. Carneiro | University of Porto | Laboratory for Process Engineering | Portugal | 2020 | Effect of temperature on growth, photosynthesis and biochemical composition of Nannochloropsis oceanica, grown outdoors in tubular photobioreactors | Since temperature is an important factor affecting microalgal growth, photosynthetic rate and biomass composition, this study has accordingly focused on its effects on biomass yield and nighttime biomass loss, as well as photochemical changes, using Nannochloropsis oceanica as model species, grown in two outdoor 50-L tubular photobioreactors (PBR). In two independent trials, cultures were subjected to a diurnal light:dark cycle, under a constant temperature of 28 °C and, on the second trial, at 18 °C. Changes in culture performance were assessed by measuring growth, lipid and fatty acid composition of the biomass in both morning and evening. Our results revealed that N. oceanica shows a wide temperature tolerance with relevant nighttime biomass loss, that decreased at lower temperatures, at the expenses of its daily productivity. Fluorescence measurements revealed reversible damage to photosystem II in cells growing in the PBR under optimal thermal conditions, whereas microalgae grown at suboptimal ones exhibited an overall lower photosynthetic activity. Lipids were partially consumed overnight to support cell division and provide maintenance energy. Eicosapentaenoic acid (EPA) catabolism reached a maximum after the dark period, as opposed to their saturated counterparts; whereas lower temperatures led to higher EPA content which reached the maximum in the morning. These findings are relevant for the production of Nannochloropsis at industrial scale. | Nannochloropsis | Temperature | Photosynthesis | Respiration | Night biomass loss | Chlorophyll fluorescence | Nannochloropsis, Temperature, Photosynthesis, Respiration, Night biomass loss, Chlorophyll fluorescence | ||||
| Chlorophyll content | CL-01 | HAL | Jordan Vacheron | Université de Lyon | UMR Ecologie Microbienne | France | 2020 | Differential contribution of plant-beneficial functions from Pseudomonas kilonensis F113 to root system architecture alterations in Arabidopsis thaliana and Zea mays | Fluorescent pseudomonads are playing key roles in plant-bacteria symbiotic interactions due to the multiple plant-beneficial functions (PBFs) they are harboring. The relative contributions of PBFs to plant-stimulatory effects of the well-known PGPR Pseudomonas kilonensis F113 (formerly P. fluorescens F113) were investigated using a genetic approach. To this end, several deletion mutants were constructed: simple mutants EphlD (impaired in the biosynthesis of 2,4-diacetylphloroglucinol [DAPG]), EacdS (deficient in 1-aminocyclopropane-1-carboxylate [ACC] deaminase activity), Egcd (glucose dehydrogenase deficient, impaired in phosphate solubilization), and EnirS (nitrite reductase deficient) and a quadruple mutant (deficient in the 4 PBFs mentioned above). Every PBF activity was quantified in the wild-type strain and the five deletion mutants. This approach revealed few functional interactions between PBFs in vitro. In particular, biosynthesis of glucose dehydrogenase severely reduced the production of DAPG. Contrariwise, the DAPG production impacted positively, but to a lesser extent, phosphate solubilization. Inoculation of the F113 wild-type strain on Arabidopsis thaliana Col-0 and maize seedlings modified the root architecture of both plants. Mutant strain inoculations revealed that the relative contribution of each PBF differed according to the measured plant traits, and that F113 plant stimulatory effects did not correspond to the sum of each PBF relative contribution. Indeed, two PBF genes (EacdS and EnirS) had a significant impact on root system architecture from both model plants, whether in in vitro and in vivo conditions. The current work underlined that few F113 PBFs seem to interact between each other in the free-living bacterial cells, whereas they control in concert Arabidopsis thaliana and maize growth and development. | co-occurring plant-beneficial functions | maize | Arabidopsis | functional interactions | fluorescent Pseudomonas | co-occurring plant-beneficial functions, maize, Arabidopsis, functional interactions, fluorescent Pseudomonas | |||||
| Oxygen electrode | Oxygraph | Cardiovascular Drugs and Therapy | Karthik Dhanabalan | University of Stellenbosch | Division of Medical Physiology | South Africa | 2020 | Mitochondrial Oxidative Phosphorylation Function and Mitophagy in Ischaemic/Reperfused Hearts from Control and High-Fat Diet Rats: Effects of Long-Term Melatonin Treatment | Purpose Oxidative stress causes mitochondrial dysfunction in myocardial ischaemia/reperfusion (I/R) as well as in obesity. Mitochondrial depolarization triggers mitophagy to degrade damaged mitochondria, a process important for quality control. The aims of this study were to evaluate (i) the effect of I/R on mitochondrial oxidative phosphorylation and its temporal relationship with mitophagy in hearts from obese rats and their age-matched controls, and (ii) the role of oxidative stress in these processes using melatonin, a free radical scavenger. Methods Male Wistar rats were divided into 4 groups: control (normal diet ± melatonin) and high-fat sucrose diet (HFSD ± melatonin). Rats received melatonin orally (10 mg/kg/day). After 16 weeks, hearts were removed and subjected to 40-min stabilization, and 25-min global ischaemia/10-min reperfusion for preparation of mitochondria. Mitochondrial oxidative phosphorylation was measured polarographically. Western blotting was used for evaluation of PINK1, Parkin, p62/SQSTM1 (p62) and TOM 70. Infarct size was measured using tetrazolium staining. Results Ischaemia and reperfusion respectively reduced and increased mitochondrial QO2 (state 3) and the ox-phos rate in both control and HFSD mitochondria, showing no major changes between the groups, while melatonin pretreatment had little effect. p62 as indicator of mitophagic flux showed up- and downregulation of mitophagy by ischaemia and reperfusion respectively, with melatonin having no significant effect. Melatonin treatment caused a significant reduction in infarct size in hearts from both control and diet groups. Conclusions The results suggest that I/R (i) affects mitochondria from control and HFSD hearts similarly and (ii) melatonin-induced cardioprotection is not associated with reversal of mitochondrial dysfunction or changes in the PINK1/Parkin pathway. | Mitochondrial oxidative phosphorylation | Mitophagy | High-fat sucrose diet | Long-term melatonin treatment | Infarct size | Cardioprotection | Mitochondrial oxidative phosphorylation, Mitophagy, High-fat sucrose diet, Long-term melatonin treatment, Infarct size, Cardioprotection | ||||
| Oxygen electrode | Oxygraph | Communications Biology | Yongting Zhang | Zhejiang University | Institute of Microbiology College of Life Sciences | China | 2020 | Nitrite modulates aminoglycoside tolerance by inhibiting cytochrome heme-copper oxidase in bacteria | As a bacteriostatic agent, nitrite has been used in food preservation for centuries. When used in combination with antibiotics, nitrite is reported to work either cooperatively or antagonistically. However, the mechanism underlying these effects remains largely unknown. Here we show that nitrite mediates tolerance to aminoglycosides in both Gram-negative and Gram-positive bacteria, but has little interaction with other types of antibiotics. Nitrite directly and mainly inhibits cytochrome heme-copper oxidases (HCOs), and by doing so, the membrane potential is compromised, blocking uptake of aminoglycosides. In contrast, reduced respiration (oxygen consumption rate) resulting from nitrite inhibition is not critical for aminoglycoside tolerance. While our data indicate that nitrite is a promising antimicrobial agent targeting HCOs, cautions should be taken when used with other antibiotics, aminoglycosides in particular. | |||||||||||
| Oxygen electrode | Chlorolab 2 | Journal of Applied Phycology | Ge Xu | Shandong University | Institute of Marine Science and Technology | China | 2020 | Photoperiod mediates the differential physiological responses of smaller Thalassiosira pseudonana and larger Thalassiosira punctigera to temperature changes | Global warming is altering both phytoplankton-experienced temperature and light-exposure duration through shifting their niches from low to high latitudes. We explored the growth, physiology, and compositions of a smaller Thalassiosira pseudonana and a larger Thalassiosira punctigera, temperate marine centric diatoms, in responses to a matrix of temperatures (12, 15, 18, and 21 °C) and photoperiods (light:dark cycles of 4:20, 8:16, 16:8, and 24:0). Both T. pseudonana and T. punctigera grew faster under medium temperature and longer photoperiod, under the expected optimal instantaneous light intensity. The biovolume-based pigments content of T. pseudonana responded largely to temperature, while that of T. punctigera responded more to photoperiod duration than to temperature. In T. pseudonana, shortest photoperiod enhanced cellular protein content and alleviated their temperature dependency. Continuous growth light reduced the photosynthetic capacity of T. pseudonana at the lowest temperature and reduced that of T. punctigera across temperatures. Moreover, we found the increasing temperature linearly increased the dark respiration rate (Rd) and molar ratio of carbon to nitrogen (C:N) of T. pseudonana but decreased that of T. punctigera, with the scattered effects of photoperiod. Our results demonstrated that responses of diatoms Thalassiosira across photoperiods and temperatures vary with species and possibly with cell size, suggesting that the poleward shift of the niches of phytoplankton in nature might cause a change in community structure. | Photoperiod | Temperature | Growth | Pigments | Dark respiration | RubisCO activity | Cell size | Diatoms Thalassiosira | Photoperiod, Temperature, Growth, Pigments, Dark respiration, RubisCO activity, Cell size, Diatoms Thalassiosira | ||
| Chlorophyll fluorescence | Handy PEA | Environmental Science and Pollution Research | Zhenxia Li | Henan Institute of Science and Technology | College of Horticulture and Landscape | China | 2020 | Physiological responses of lettuce (Lactuca sativa L.) to microplastic pollution | Concerns about the pollution of farmlands by microplastics and the associated toxicology have increased in recent times; however, studies on this topic are scarce. In this study, two kinds of PVC microplastics with different particle sizes (PVC-a with particle sizes from 100 nm to 18 μm, and PVC-b with particle sizes from 18 to 150 μm) and different content levels (0.5%, 1%, and 2%) were used to analyze the effects of PVC microplastics on the physiological characteristics of the lettuce root system and leaves. The results showed that PVC-a and PVC-b had no significant effect on the lettuce root activity. However, 0.5%a and 1%a significantly increased the total length, surface area, volume, and diameter of roots. In terms of leaves, PVC-a and PVC-b had no significant effect on the malondialdehyde content, but 1%a significantly increased the superoxide dismutase activity. Carotenoid synthesis was promoted by PVC-a but inhibited by PVC-b. Furthermore, 1%a could reduce the ability of light energy absorption, dissipation, capture, and electron transfer. The gray correlation analysis indicated that PVC-a correlated to a considerable degree with the indices related to photosynthesis, while PVC-b was significantly correlated with the indices related to root morphology. This study provides insights into the ecotoxicological effect of microplastics on farmland crops and associated ecological risk assessment. | Chlorophyll fluorescence | Lettuce | Malondialdehyde | Microplastic | Root | Superoxide dismutase | Chlorophyll fluorescence, Lettuce, Malondialdehyde, Microplastic, Root, Superoxide dismutase | ||||
| Oxygen electrode | Oxytherm | The Journal of Biochemistry | Aya Okuda | Kyoto University | Division of Agronomy and Horticultural Science | Japan | 2020 | A novel soybean protein disulfide isomerase family protein possesses dithiol oxidation activity: Identification and characterization of GmPDIL6 | Secretory and membrane proteins synthesized in the endoplasmic reticulum (ER) are folded with intramolecular disulfide bonds, viz. oxidative folding, catalyzed by the protein disulfide isomerase (PDI) family proteins. Here, we identified a novel soybean PDI family protein, GmPDIL6. GmPDIL6 has a single thioredoxin-domain with a putative N-terminal signal peptide and an active center (CKHC). Recombinant GmPDIL6 forms various oligomers binding iron. Oligomers with or without iron binding, and monomers exhibited a dithiol oxidase activity level comparable to those of other soybean PDI family proteins. However, they displayed no disulfide reductase and extremely low oxidative refolding activity. Interestingly, GmPDIL6 was mainly expressed in the cotyledon during synthesis of seed storage proteins and GmPDIL6 mRNA was upregulated under ER stress. GmPDIL6 may play a role in the formation of disulfide bonds in nascent proteins for oxidative folding in the ER. | Endoplasmic Reticulum | Protein Disulfide Isomerase | Protein Folding | Unfolded Protein Response | Soybean | Endoplasmic Reticulum, Protein Disulfide Isomerase, Protein Folding, Unfolded Protein Response, Soybean | |||||
| Oxygen electrode | Chlorolab 2 | Plant Physiology and Biochemistry | Julia Elise Fontana | Henan Institute of Science and Technology | Henan Key Laboratory for Molecular Ecology | China | 2020 | Impact of potassium deficiency on cotton growth, development and potential microRNA-mediated mechanism | The goal of this study was to investigate the impact of potassium deficiency on cotton seedling growth and development at the individual, physiological, biochemical, and molecular levels. Potassium is an important plant nutrient; our results show that potassium deficiency significantly affected cotton seedling growth and development, evidenced by reduced plant height, and total areas of the leaves and roots as well as further reduced both fresh and dry biomass of the entire plants. Potassium deficiency also significantly inhibited root and leaf respiration and leaf photosynthesis. Compared with the controls, potassium deficiency significantly inhibited root elongation and total root surface areas that further inhibited cotton seedlings to uptake nutrients from the medium. Potassium deficiency induced aberrant expression of both microRNAs (miRNAs) and their protein-coding targets. These miRNAs regulate plant root development as well as response to abiotic stresses. Potassium deficiency altered the expression of miRNAs that regulate the expression of protein-coding genes controlling root development and response to potassium deficiency. miRNAs regulate root development and further control plant development in cotton seedlings under potassium deficiency. In summary, potassium deficiency significantly affected the cotton seedling photosynthesis and respiration that resulted in inhibition of cotton seedling growth and development potentially due to the miRNA-mediated mechanism. | Cotton | Nutrient deficiency | Potassium | Development | Biomass | Root | MicroRNA | Cotton, Nutrient deficiency, Potassium, Development, Biomass, Root, MicroRNA | |||
| Oxygen electrode | Oxygraph | Plant Physiology and Biochemistry | Ling Li | The Chinese Academy of Sciences | Key Laboratory of Plant Resources/Beijing Botanical Garden | China | 2020 | An innovative artificial photosystem II constructed from PSII core of Thermosynechococcus vulcanus and LHCII of Pisum sativum - A new approach for studying the function of photosynthetic antenna | In photosynthesis, the antenna system captures solar energy and transfers the excitations to photosystem II (PSII) core complex where charge separation, water splitting and oxygen evolution occur. In the evolution of photosynthesis from aquatic to terrestrial environments, the structure of PSII core complex was highly conserved while a variety of antenna forms became differentiated. In order to study the principles for energy transport from antenna to the PSII reaction center, we have explored whether the major light harvesting complex of PSII (LHCII) of higher plants can transfer energy to the cyanobacteria PSII core complexes (CC). For this purpose, LHCII from pea and CC from Thermosynechococcus vulcanus were isolated and co-reconstituted into liposome at LHCII:CC molar ratios of 2:1, 4:1 and 6:1, respectively. Chemical-cross linking followed by LC-MS/MS analysis confirmed the biochemical interaction between LHCII and CC in the liposome membrane. The analyses of 77 K fluorescence emission spectra and antenna cross section of PSII indicated that LHCII can transfer energy directly to the cyanobacterial CC. The study has laid the basis for further research on the mechanism of energy transfer from LHCII to PSII CC. This result may also open a new possibility for design and development of new artificial PSII in the application of solar energy conversion. | Photosystem II | LHCII | Proteoliposome | Energy transfer | Photosystem II, LHCII, Proteoliposome, Energy transfer | ||||||
| Chlorophyll fluorescence | Handy PEA | Plant Physiology and Biochemistry | Ling Li | The Chinese Academy of Sciences | Key Laboratory of Plant Resources/Beijing Botanical Garden | China | 2020 | An innovative artificial photosystem II constructed from PSII core of Thermosynechococcus vulcanus and LHCII of Pisum sativum - A new approach for studying the function of photosynthetic antenna | In photosynthesis, the antenna system captures solar energy and transfers the excitations to photosystem II (PSII) core complex where charge separation, water splitting and oxygen evolution occur. In the evolution of photosynthesis from aquatic to terrestrial environments, the structure of PSII core complex was highly conserved while a variety of antenna forms became differentiated. In order to study the principles for energy transport from antenna to the PSII reaction center, we have explored whether the major light harvesting complex of PSII (LHCII) of higher plants can transfer energy to the cyanobacteria PSII core complexes (CC). For this purpose, LHCII from pea and CC from Thermosynechococcus vulcanus were isolated and co-reconstituted into liposome at LHCII:CC molar ratios of 2:1, 4:1 and 6:1, respectively. Chemical-cross linking followed by LC-MS/MS analysis confirmed the biochemical interaction between LHCII and CC in the liposome membrane. The analyses of 77 K fluorescence emission spectra and antenna cross section of PSII indicated that LHCII can transfer energy directly to the cyanobacterial CC. The study has laid the basis for further research on the mechanism of energy transfer from LHCII to PSII CC. This result may also open a new possibility for design and development of new artificial PSII in the application of solar energy conversion. | Photosystem II | LHCII | Proteoliposome | Energy transfer | Photosystem II, LHCII, Proteoliposome, Energy transfer | ||||||
| Chlorophyll fluorescence | Handy PEA | BIOLOGIA PLANTARUM | A.A. YOUNIS | Ain Shams University | Botany Department | Egypt | 2020 | Impacts of silicon and silicon nanoparticles on leaf ultrastructure and TaPIP1 and TaNIP2 gene expressions in heat stressed wheat seedlings | Heat stress is one of the most crucial factors affecting crop growth and productivity worldwide. So, searching for a potent eco-friendly heat stress alleviator is the main issue nowadays. The current study was conducted to assess the ameliorative effects of 1.5 mM potassium silicate (K2SiO3, further only Si) or 1.66 mM silicon dioxide nanoparticles (SiNPs) on wheat (Triticum aestivum L.) seedlings exposed to heat stress (45 °C, 4 h). The observations show that Si or SiNPs treatments significantly restored the heat stress-provoked ultrastructural distortions of cellular organelles, particularly chloroplasts and the nucleus. Further, both Si and SiNPs enhanced the photosynthetic capacity as revealed by increments in the photochemical efficiency of photosystem II and the performance index as well as the content of photosynthetic pigments. A reduction in malondialdehyde accumulation in Si and SiNPs treated plants was positively related to their membrane stability index. The reverse transcription PCR analysis showed that Si treatment but not SiNP treatment stimulated the overexpressions of both Triticum aestivum plasma membrane intrinsic protein (TaPIP1) and Triticum aestivum nodulin 26-like intrinsic protein (TaNIP2) aquaporin genes parallelly with an improvement in the relative water content. This investigation reveals that Si was more effective than SiNPs in restoring the heat stress injuries. To the best of our knowledge, this is the first investigation exploring the effects of Si and SiNPs in improving thermotolerance of wheat seedlings. | aquaporins | chlorophyll content | chlorophyll fluorescence | membrane stability | photosystem II | Triticum aestivum | aquaporins, chlorophyll content, chlorophyll fluorescence, membrane stability, photosystem II, Triticum aestivum | ||||
| Chlorophyll fluorescence | Handy PEA | Biologia | Stefano Loppi | University of Siena | Department of Life Sciences | Italy | 2020 | Uptake and release of copper ions in epiphytic lichens | This study investigated the uptake and release of Cu ions in the epiphytic lichen Evernia prunastri, a species widely used to monitor trace metal pollution. A cross transplant experiment from a background area to a polluted one and then back to an unpolluted one was simulated by incubating lichen thalli with 10 and 100 µM Cu2+ solutions and subsequently in deionized water to induce metal release. The working hypothesis was that after the accumulation of Cu ions, a forced release brings the concentration back to the original values. Copper treatment caused a significant uptake, proportional to the concentrations in the solution. Accumulation occurred mostly extracellularly (90% after incubation with Cu 10 µM and 60% with Cu 100 µM). The subsequent induced release was evident only in samples treated with 100 µM, and was determined by the loss from intracellular compartments. Lichen vitality, expressed in terms of photosynthetic efficiency, was not affected by Cu treatment. It is concluded that while ionic uptake is a fast process, metal release requires a much longer time. In addition, it is confirmed that the cell wall is a buffer between the outer environment and the cell interior. | Bioaccumulation | Biomonitoring | Evernia prunastri | Heavymetals | Photosynthetic efficiency | Bioaccumulation, Biomonitoring, Evernia prunastri, Heavymetals, Photosynthetic efficiency | |||||
| Chlorophyll fluorescence | FMS 2 | American Journal of Botany | Xiao-Yang Fan | Chinese Academy of Sciences | CAS Key Laboratory of Tropical Forest Ecology | China | 2020 | A combination of morphological and photosynthetic functional traits maintains the vertical distribution of bryophytes in a subtropical cloud forest | Premise The distribution and performance of bryophyte species vary with vertical gradients, as a result of changes in environmental factors, especially light. However, the morphological and physiological drivers of bryophyte distribution along forest vertical gradients are poorly understood. Methods For 18 species of mosses and liverworts distributed among three vertical microhabitats (ground, tree trunk, and branch, variance in 28 morphological and photosynthetic functional traits was comparatively analyzed among the microhabitats and bryophyte life‐forms in a subtropical cloud forest in Ailao Mountain, Yunnan, southwestern China. Principal component analysis (PCA ) was used to summarize trait differences among bryophyte species. Results In contrast to trunk and ground dwellers, branch dwellers tended to reduce light interception (smaller leaf and cell sizes, lower chlorophyll content), protect against damage from intense irradiation (higher ratios of carotenoids to chlorophyll), raise light energy use (higher photosynthetic capacity), and cope with lower environmental moisture (pendant life‐forms, thicker cell walls). The PCA showed that ecological strategies of bryophytes in response to levels of irradiation were specialized in branch dwellers, although those of ground and trunk dwellers were less distinct. Conclusions Environmental filtering shaped the combination of functional traits and the spatial distribution of bryophytes along the vertical gradients. Bryophyte species from the upper canopy of cloud forests show narrow variation in functional traits in high‐light intensity, whereas species in the lower vertical strata associated with low‐light intensity used contrasting, but more diverse ecological strategies. | chlorophyll fluorescence | ecophysiology | epiphytic moss | light relations | Meteoriaceae | Neckeraceae | trade-off | chlorophyll fluorescence, ecophysiology, epiphytic moss, light relations, Meteoriaceae, Neckeraceae, trade-off | |||
| Chlorophyll fluorescence | FMS 2 | Food Science & Nutrition | Li Zhang | Shihezi University | Key Laboratory of Agricultural Biotechnology | China | 2020 | Overexpression of SikRbcs2 gene promotes chilling tolerance of tomato by improving photosynthetic enzyme activity, reducing oxidative damage, and stabilizing cell membrane structure | Red blood cell is a small subunit encoding 1, 5-ribulose bisphosphate carboxylase/oxygenase (Rubisco). It could control the catalytic activity of Rubisco and play an important role in plant photosynthesis. SikRbcs2, a small subunit of Rubisco, is cloned from Saussurea involucrate. It has a strong low-temperature photosynthetic and photorespiration ability, but its mechanism in cold tolerance remains to be unknown. The results of quantitative PCR showed that SikRbcS2 gene could be induced by low-temperature, osmosis, and salt stress. Its expression was increased with the decrease of temperature, which was consistent with the habitat of Saussurea involucrata. Overexpression of Sikrbcs2 could significantly increase the mRNA expressions of SlrbcL and SlRCA in transgenic tomato seedlings. Furthermore, the activity and content of Rubisco and Rubisco activase (RCA) in transgenic tomato seedlings were also significantly higher than those in wild-type plants. The contents of chlorophyll and carotenoids, soluble sugar, and starch in the leaves of transgenic plants were significantly higher than those in WT plants, as well as the plant height, leaf area, and dry matter weight. Moreover, compared with WT, MDA content was decreased, and activities of SOD, POD, CAT, and APX were significantly higher in transgenic lines. In conclusion, our results suggested that overexpression of SikRbcs2 can reduce the damage of low temperature on photosynthesis of tomato seedlings. It could help achieve relatively stable photosynthesis, enhance scavenging ROS ability of tomato seedlings, maintain stable membrane structure, and improve cold tolerance of tomato. | chlorophyll fluorescence | low-temperature tolerance | photosynthesis | Saussurea involucrata | SikRbcS2 | tomato | chlorophyll fluorescence, low-temperature tolerance, photosynthesis, Saussurea involucrata, SikRbcS2, tomato | ||||
| Chlorophyll content | CL-01 | Journal of Plant Nutrition | Marjan Tabesh | Shahrekord University | Department of Soil Science and Engineering | Iran | 2020 | The effectiveness of seed priming and foliar application of zinc- amino acid chelates in comparison with zinc sulfate on yield and grain nutritional quality of common bean | The efficacy of seed priming and foliar application of zinc-amino acid chelates including zinc-histidine [Zn(His)2] and zinc-methionine [Zn(Met)2] in comparison with zinc sulfate (ZnSO4) on yield and grain nutritional quality of two common bean cultivars (Phaseolus vulgaris L., cvs Talash and Sadri) was investigated in a severely Zn-deficient calcareous soil (DTPA-Zn: 0.38 mg kg−1 soil) in a pot experiment. Bean response to Zn application varied depending on the Zn fertilizer, application method and cultivar. In ‘Talash’, seed priming with [Zn(His)2] and [Zn(Met)2] led to 24.1 and 11.6% increase in the grain yield of bean in comparison with ZnSO4 treatment, respectively. In both cultivars, foliar application of [Zn(His)2] led to significant increase in the grain yield in comparison with ZnSO4. The highest grain Zn concentration was obtained by seed priming with [Zn(Met)2] in ‘Sadri’ and [Zn(His)2] in ‘Talash’, respectively. For Zn-amino acid chelates, seed priming was more effective than foliar application in increasing grain yield and Zn concentration. Foliar application of [Zn(His)2] and [Zn(Met)2] in ‘Sadri’ and [Zn(Met)2] in ‘Talash’ resulted in higher protein content in bean grain as compared with ZnSO4. In both cultivars, foliar application of [Zn(Met)2] was the more effective than seed priming to increase grain protein content. The highest water-soluble carbohydrates concentration of grain was obtained by seed priming with [Zn(Met)2] and [Zn(His)2] in ‘Sadri’ and ‘Talash’ cultivars, respectively. Therefore, seed priming with [Zn(His)2] and ZnSO4 in ‘Sadri’ and [Zn(Met)2] in ‘Talash’ can effectively be used for improving yield of common bean in Zn-deficient calcareous soils. | fertilizer management | grain protein | Phaseolus vulgaris L | water-soluble carbohydrates | zinc | fertilizer management, grain protein, Phaseolus vulgaris L, water-soluble carbohydrates, zinc | |||||
| Chlorophyll fluorescence | FMS 2 | Plant Physiology and Biochemistry | Enrique Mateos-Naranjo | Universidad de Sevilla | Departamento de Biología Vegetal y Ecología | Spain | 2020 | Uncovering PGPB Vibrio spartinae inoculation-triggered physiological mechanisms involved in the tolerance of Halimione portulacoides to NaCl excess | Plant growth promoting bacteria’ (PGPB) beneficial role on plant tolerance to salinity stress has previously been well recognized. However, bacteria-triggered plant physiological mechanisms involved in this response require investigation, especially in plants with innate salt tolerance. A glasshouse experiment was designed to investigate the effect of the PGPB Vibrio spartinae on Halimione portulacoides growth, physiological performance and ion homeostasis in plants exposed to 0, 171, 510 and 1020 mM NaCl for 100 days. Bacterial inoculation alleviated ∼28% of the deleterious impact of salinity excess on the relative growth rate (RGR) in plants grown at 510 mM and led to 30% and 44% enhancements in those exposed to 0 and 171 mM NaCl, respectively. This effect was linked to a reduction in Na tissue concentrations which improved plant ion homeostasis at elevated NaCl concentration, and to the overall protective effects on various steps in the photosynthetic pathway between 0 and 510 mM NaCl. Thus, inoculated plants were able to maintain higher net photosynthesis (AN) than their non-inoculated counterparts. Hence, AN differences under saline conditions were ascribed to inoculation amelioration NaCl-induced CO2 diffusion limitations, as reflected in the greater gs and Ci values recorded at 171 and 510 mM NaCl, together with an enhancement of photochemical apparatus functionality (in terms of energy absorption, transformation and transport), as indicated by a higher electron transport rate (ETR) and energy fluxes derived from Kautsky curves, compared with their non-inoculated counterparts. | Chlorophyll fluorescence | Gas exchange | Halophyte | Ion homeostasis | NaCl-Stress | Chlorophyll fluorescence, Gas exchange, Halophyte, Ion homeostasis, NaCl-Stress | |||||
| Oxygen electrode | Oxytherm | MDPI: Inorganics | Janik Telleria Marloth | Martin-Luther-University | Institute for Biology/Microbiology | Germany | 2020 | Susceptibility of the Formate Hydrogenlyase Reaction to the Protonophore CCCP Depends on the Total Hydrogenase Composition | Fermentative hydrogen production by enterobacteria derives from the activity of the formate hydrogenlyase (FHL) complex, which couples formate oxidation to H2 production. The molybdenum-containing formate dehydrogenase and type-4 [NiFe]-hydrogenase together with three iron-sulfur proteins form the soluble domain, which is attached to the membrane by two integral membrane subunits. The FHL complex is phylogenetically related to respiratory complex I, and it is suspected that it has a role in energy conservation similar to the proton-pumping activity of complex I. We monitored the H2-producing activity of FHL in the presence of different concentrations of the protonophore CCCP. We found an inhibition with an apparent EC50 of 31 μM CCCP in the presence of glucose, a higher tolerance towards CCCP when only the oxidizing hydrogenase Hyd-1 was present, but a higher sensitivity when only Hyd-2 was present. The presence of 200 mM monovalent cations reduced the FHL activity by more than 20%. The Na+/H+ antiporter inhibitor 5-(N-ethyl-N-isopropyl)-amiloride (EIPA) combined with CCCP completely inhibited H2 production. These results indicate a coupling not only between Na+ transport activity and H2 production activity, but also between the FHL reaction, proton import and cation export. | formate hydrogenlyase | hydrogen metabolism | energy conservation | MRP (multiple resistance and pH)-type Na+/H+ antiporter | CCCP—carbonyl cyanide m-chlorophenyl-hydrazone | EIPA—5-(N-ethyl-N-isopropyl)-amiloride | formate hydrogenlyase, hydrogen metabolism, energy conservation, MRP (multiple resistance and pH)-type Na+/H+ antiporter, CCCP—carbonyl cyanide m-chlorophenyl-hydrazone, EIPA—5-(N-ethyl-N-isopropyl)-amiloride | ||||
| Oxygen electrode | OXY/ECU | MDPI: Inorganics | Janik Telleria Marloth | Martin-Luther-University | Institute for Biology/Microbiology | Germany | 2020 | Susceptibility of the Formate Hydrogenlyase Reaction to the Protonophore CCCP Depends on the Total Hydrogenase Composition | Fermentative hydrogen production by enterobacteria derives from the activity of the formate hydrogenlyase (FHL) complex, which couples formate oxidation to H2 production. The molybdenum-containing formate dehydrogenase and type-4 [NiFe]-hydrogenase together with three iron-sulfur proteins form the soluble domain, which is attached to the membrane by two integral membrane subunits. The FHL complex is phylogenetically related to respiratory complex I, and it is suspected that it has a role in energy conservation similar to the proton-pumping activity of complex I. We monitored the H2-producing activity of FHL in the presence of different concentrations of the protonophore CCCP. We found an inhibition with an apparent EC50 of 31 μM CCCP in the presence of glucose, a higher tolerance towards CCCP when only the oxidizing hydrogenase Hyd-1 was present, but a higher sensitivity when only Hyd-2 was present. The presence of 200 mM monovalent cations reduced the FHL activity by more than 20%. The Na+/H+ antiporter inhibitor 5-(N-ethyl-N-isopropyl)-amiloride (EIPA) combined with CCCP completely inhibited H2 production. These results indicate a coupling not only between Na+ transport activity and H2 production activity, but also between the FHL reaction, proton import and cation export. | formate hydrogenlyase | hydrogen metabolism | energy conservation | MRP (multiple resistance and pH)-type Na+/H+ antiporter | CCCP—carbonyl cyanide m-chlorophenyl-hydrazone | EIPA—5-(N-ethyl-N-isopropyl)-amiloride | formate hydrogenlyase, hydrogen metabolism, energy conservation, MRP (multiple resistance and pH)-type Na+/H+ antiporter, CCCP—carbonyl cyanide m-chlorophenyl-hydrazone, EIPA—5-(N-ethyl-N-isopropyl)-amiloride | ||||
| Oxygen electrode | S1 | Journal of Plant Growth Regulation | Vijay Kumar | Himachal Pradesh University | Department of Biosciences | India | 2020 | Differential Arsenic-Induced Membrane Damage and Antioxidant Defence in Isolated Pinna Segments of Selected Fern Species from Western Himalaya | A comparative evaluation of arsenic (As)-induced toxicity has been made in selected Western Himalayan ferns belonging to the family Pteridaceae (Pteris vittata L. and P. cretica L.) and Polypodiaceae (Polypodiodes microrhizoma (C. B. Clarke ex Baker) Ching and Lepisorus contortus (H. Chirst) Ching) employing a rapid leaf (pinna) slice test. The exposure of pinna segments to As(V) (Na2HAsO4; 0–1000 µM), led to a concentration-dependent increase in K+ leakage into the incubation medium owing to membrane damage. Strong species-specific differences were evident. Thus, the magnitude of K+ leakage enhancement was much lower in Pteridaceae members (lowest in P. vittata) than in those of Polypodiaceae. The As effects were like those of Cu, a redox active element like As, and H2O2 suggesting them to be mediated by oxidative stress. Involvement of K+ channels in As-induced K+ leakage is unlikely, as no effect of tetraethylammonium chloride (TEA), a K+ channel inhibitor was evident. Furthermore, the activities of antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were markedly altered due to As treatment in a species-specific manner pointing to a role of antioxidant defence in differential response and thereby tolerance of the concerned ferns to As. Findings have implications for phytoremediation. | Arsenic | Ferns | Pteridaceae | Polypodiaceae | K+ leakage | Antioxidative defence | Arsenic, Ferns, Pteridaceae, Polypodiaceae, K+ leakage, Antioxidative defence | ||||
| Chlorophyll fluorescence | Handy PEA | Acta Astronautica | Chairat Treesubsuntorn | King Mongkut's University of Technology | Pilot Plant Development and Training Institute | Thailand | 2020 | Enhancing benzene removal by Chlorophytum comosum under simulation microgravity system: Effect of light-dark conditions and indole-3-acetic acid | Air phytoremediation technology has been reported as a high potential technology for indoor air pollution treatment. Since 1996, NASA has supported this technology for application in the international space station. However, changes in plant physiology and hormone levels under microgravity (μG) conditions might affect air phytoremediation efficiency, especially changes of auxin hormone transportation in plants. In this study, the application of Chlorophytum comosum, high benzene removal plant species, to remove 100 ppm gaseous benzene under μG condition was studied. The experiment was operated for three days in a random positioning machine generate 6.44 × 10−4 G within 1 h. The results showed that under μG, benzene removal efficiency by C. comosum was significantly increased, with a remove more than 80% within three days under both 24 h light and dark conditions. In contrast, C. comosum growing under normal gravity (1G) can remove about 75% and 50% benzene under 24 h light and 24 h dark conditions, respectively. Surprisingly, μG conditions seem to maintain open stomata of a plant open under both 24 h light and dark conditions, and this plant will normally have closed stomata in the dark. In this case, shoot auxin hormone in the form of Indole-3-acetic acid was highly increased in the plant growing under μG. This result suggested that under μG, auxin hormone might be accumulated in the shoot part of plant. This auxin accumulation effect of maintaining open plant stomata can enhance benzene phytoremediation efficiency since stomata are the major benzene uptake pathway. Therefore, this study is the first report presenting the possibility of applying air phytoremediation technology under μG conditions. | Air Phytoremediation | Auxin | Benzene | Chlorophytum comosum | Microgravity | Air Phytoremediation, Auxin, Benzene, Chlorophytum comosum, Microgravity | |||||
| Chlorophyll fluorescence | Handy PEA | ACTA BOTANICA CROATICA | Hrvoje Lepeduš | Josip Juraj Strossmayer University of Osijek | Faculty of Humanities and Social Sciences | Croatia | 2020 | Effects of low and high irradiation levels on growth and PSII efficiency in Lemna minor L. | Plant growth and reproduction depend on light energy that drives photosynthesis. In the present study we compared growth characteristics, photosynthetic pigments content and photosystem II (PSII) performance in Lemna minor L. grown in two different irradiation regimes: low light (LL) – 50 μmolPHOTONS m-2 s-1 and high light (HL) – 500 μmolPHOTONS m-2 s-1. The main goal was to investigate the photosynthetic regulatory mechanisms that ensure adjustment to different light conditions and integrate these observations with the data on plant multiplication and biomass production. For this purpose, we measured chlorophyll (Chls) and carotenoid (Cars) contents and analyzed the energy fluxes through the PSII by saturation pulse method as well as by Chl a transient induction and JIP test. In a comparison of the effect of LL and HL on plant multiplication and fresh biomass, it was shown that the effect on growth was primarily attributed to the biomass reduction in LL while the effect on number of plants was much smaller. Total Chl and Cars contents were decreased in plants exposed to HL which indicated long-term acclimation response to the increased irradiance. Furthermore, the HLplants revealed better capability for the utilization of absorbed light in photosynthesis accompanied by photoprotective adjustment of certain number of PSII reaction centers from active to dissipative mode of functioning. In conclusion, our study showed that duckweed plants had great adjustment potential to different irradiation conditions, which might be of great importance not only under variable light availability but also when simultaneously challenged by some other environmental disturbance (e.g. different pollutants). | chlorophyll fluorescence | duckweed | growth | JIP test | light | photosynthesis | photosynthetic pigments | photosystem II | chlorophyll fluorescence, duckweed, growth, JIP test, light, photosynthesis, photosynthetic pigments, photosystem II | ||
| Oxygen electrode | S1 | Biochimica et Biophysica Acta (BBA) - Bioenergetics | Robert D. Fagerlund | University of Otago | Department of Biochemistry | New Zealand | 2020 | Stabilization of Photosystem II by the PsbT protein impacts photodamage, repair and biogenesis | Photosystem II (PS II) catalyzes the light-driven process of water splitting in oxygenic photosynthesis. Four core membrane-spanning proteins, including D1 that binds the majority of the redox-active co-factors, are surrounded by 13 low-molecular-weight (LMW) proteins. We previously observed that deletion of the LMW PsbT protein in the cyanobacterium Synechocystis sp. PCC 6803 slowed electron transfer between the primary and secondary plastoquinone electron acceptors QA and QB and increased the susceptibility of PS II to photodamage. Here we show that photodamaged ∆PsbT cells exhibit unimpaired rates of oxygen evolution if electron transport is supported by HCO3− even though the cells exhibit negligible variable fluorescence. We find that the protein environment in the vicinity of QA and QB is altered upon removal of PsbT resulting in inhibition of QA− oxidation in the presence of 2,5-dimethyl-1,4-benzoquinone, an artificial PS II-specific electron acceptor. Thermoluminescence measurements revealed an increase in charge recombination between the S2 oxidation state of the water-oxidizing complex and QA− by the indirect radiative pathway in ∆PsbT cells and this is accompanied by increased 1O2 production. At the protein level, both D1 removal and replacement, as well as PS II biogenesis, were accelerated in the ∆PsbT strain. Our results demonstrate that PsbT plays a key role in optimizing the electron acceptor complex of the acceptor side of PS II and support the view that repair and biogenesis of PS II share an assembly pathway that incorporates both de novo synthesis and recycling of the assembly modules associated with the core membrane-spanning proteins. | Acceptor side | Bioenergetics | Low-molecular-weight proteins | Photosynthesis | Photosystem II | Cyanobacteria | Acceptor side, Bioenergetics, Low-molecular-weight proteins, Photosynthesis, Photosystem II, Cyanobacteria | ||||
| Oxygen electrode | S1 | Plant Direct | Serena Golin | University of Padova | Department of Biology | Italy | 2020 | WHIRLY2 plays a key role in mitochondria morphology, dynamics, and functionality in Arabidopsis thaliana | WHIRLY2 is a single-stranded DNA binding protein associated with mitochondrial nucleoids. In the why 2-1 mutant of Arabidopsis thaliana, a major proportion of leaf mitochondria has an aberrant structure characterized by disorganized nucleoids, reduced abundance of cristae, and a low matrix density despite the fact that the macroscopic phenotype during vegetative growth is not different from wild type. These features coincide with an impairment of the functionality and dynamics of mitochondria that have been characterized in detail in wild-type and why 2-1 mutant cell cultures. In contrast to the development of the vegetative parts, seed germination is compromised in the why 2-1 mutant. In line with that, the expression level of why 2 in seeds of wild-type plants is higher than that of why 3, whereas in adult plant no difference is found. Intriguingly, in early stages of shoots development of the why 2-1 mutant, although not in seeds, the expression level of why 3 is enhanced. These results suggest that WHIRLY3 is a potential candidate to compensate for the lack of WHIRLY2 in the why 2-1 mutant. Such compensation is possible only if the two proteins are localized in the same organelle. Indeed, in organello protein transport experiments using intact mitochondria and chloroplasts revealed that WHIRLY3 can be dually targeted into both, chloroplasts and mitochondria. Together, these data indicate that the alterations of mitochondria nucleoids are tightly linked to alterations of mitochondria morphology and functionality. This is even more evident in those phases of plant life when mitochondrial activity is particularly high, such as seed germination. Moreover, our results indicate that the differential expression of why 2 and why 3 predetermines the functional replacement of WHIRLY2 by WHIRLY3, which is restricted though to the vegetative parts of the plant. | Arabidopsis thaliana | mitochondria | nucleoid | seed germination | Arabidopsis thaliana, mitochondria, nucleoid, seed germination | ||||||
| Oxygen electrode | Oxytherm | Antioxidants & Redox Signaling | Dr. Nivea Dias AMOEDO | Functional Genomics Center | CELLOMET | France | 2020 | TARGETING HUMAN LUNG ADENOCARCINOMA WITH A SUPPRESSOR OF MITOCHONDRIAL SUPEROXIDE PRODUCTION | Aims: REDOX signaling from reactive oxygen species generated by the mitochondria (mtROS) has been implicated in cancer growth and survival. Here, we investigated the effect of AOL (5-(4-methoxyphenyl)-3H-1,2-dithiole-3-thione), a recently characterized member of the new class of mtROS suppressors (S1QELs), on human lung adenocarcinoma proteome reprogramming, bioenergetics and growth. Results: AOL reduced steady-state cellular ROS levels in human lung cancer cells without altering the catalytic activity of complex I. AOL treatment induced dose-dependent inhibition of lung cancer cell proliferation and triggered a reduction in tumor growth in vivo. Molecular investigations demonstrated that AOL reprogrammed the proteome of human lung cancer cells. In particular, AOL suppressed the determinants of the Warburg effect and reduced the expression of STAT3, a master regulator of lung carcinogenesis. Comparison of the molecular changes induced by AOL and MitoTEMPO, a mtROS scavenger that is not a S1QEL, identified a core component of 217 proteins commonly altered by the two treatments, as well as drug-specific targets. Innovation: This study provides proof-of-concept data on the anticancer effect of AOL on mouse orthotopic human lung tumors. A unique dataset on proteomic reprogramming by AOL and MitoTEMPO is also provided. Last, our study revealed the repression of STAT3 by S1QEL AOL. Conclusion: Our findings demonstrate the preclinical anticancer properties of S1QEL AOL and delineate its mode of action on REDOX and cancer signaling. | Mitochondria | reactive oxygen species | complex I | AOL | MitoTEMPO | STAT3 | Mitochondria, reactive oxygen species, complex I, AOL, MitoTEMPO, STAT3 | ||||
| Chlorophyll fluorescence | Handy PEA | Frontiers in Plant Science | Yuansong Xiao | Shandong Agricultural University | State Key Laboratory of Crop Biology | China | 2020 | Hydrogen Sulfide Alleviates Waterlogging-Induced Damage in Peach Seedlings via Enhancing Antioxidative System and Inhibiting Ethylene Synthesis | Peach (Prunus persica L. Batsch) is a shallow root fruit tree with poor waterlogging tolerance. Hydrogen sulfide (H2S) is a signal molecule which regulates the adaptation of plants to adverse environments. Nevertheless, the effects of exogenous applications of H2S in fruit tree species especially in peach trees under waterlogging stress have been scarcely researched. Thus, the goal of this research was to investigate the alleviating effect of exogenous H2S on peach seedlings under waterlogging stress. In the present study, we found that the effect of exogenous H2S depended on the concentration and 0.2 mM sodium hydrosulfide (NaHS) showed the best remission effect on peach seedlings under waterlogging stress. Waterlogging significantly reduced the stomatal opening, net photosynthetic rate, and Fv/Fm of peach seedlings. The results of histochemical staining and physiological and biochemical tests showed that waterlogging stress increased the number of cell deaths and amounts of reactive oxygen species (ROS) accumulated in leaves, increased the number of root cell deaths, significantly increased the electrolyte permeability, O2.– production rate, H2O2 content and ethylene synthesis rate of roots, and significantly reduced root activity. With prolonged stress, antioxidative enzyme activity increased initially and then decreased. Under waterlogging stress, application of 0.2 mM NaHS increased the number of stomatal openings, improved the chlorophyll content, and photosynthetic capacity of peach seedlings. Exogenous H2S enhanced antioxidative system and significantly alleviate cell death of roots and leaves of peach seedlings caused by waterlogging stress through reducing ROS accumulation in roots and leaves. H2S can improve the activity and proline content of roots, reduce oxidative damage, alleviated lipid peroxidation, and inhibit ethylene synthesis. The H2S scavenger hypotaurine partially eliminated the effect of exogenous H2S on alleviating waterlogging stress of peach seedlings. Collectively, our results provide an insight into the protective role of H2S in waterlogging-stressed peach seedlings and suggest H2S as a potential candidate in reducing waterlogging-induced damage in peach seedlings. | hydrogen sulfide | peach seedlings | antioxidative system | ethylene | waterlogging stress | hydrogen sulfide, peach seedlings, antioxidative system, ethylene, waterlogging stress | |||||
| Chlorophyll fluorescence | Handy PEA | Biomass and Bioenergy | Peter Ferus | Institute of Forest Ecology SAS | Mlyňany Arboretum | Slovakia | 2020 | Productivity and heat-stress tolerance in Canadian poplar (Populus × canadensis Moench) clones with different ecological optimum | Cultivation of fast growing poplar (Populus sp.) clones represents an effective means for reaching the 2020 target of the EU-28 renewable energy production. However, considering the continuous climate change, their growth can be markedly affected by summer heat stress episodes in Slovakia. Therefore, in this work two Canadian poplar (Populus × canadensis Moench) clones of different ecological optimum, ‘Gigant' and ‘Pannonia', were investigated in respect of productivity and heat stress tolerance. After three-year cultivation, tree height in the clone ‘Gigant' was 8.9 m, breast trunk diameter 9.3 cm and trunk volume 0.021 m3 compared to 7.9 m, 7.0 cm and 0.012 m3 in clone ‘Pannonia' (despite of relatively more stable trunk growth rate in summer). Trunks of the latter clone contained 12% bark (vs. 10% in ‘Gigant'), 1.5% ash in the wood (vs. 3%) and showed significantly larger wood density (440 vs. 380 kg m−3) but lower wood free energy content (14.5 vs. 16 MJ kg−1). Both of clones were proved to be diploids (2x). Clone ‘Pannonia' exhibited larger heat stress tolerance, as tested in leaves of different developmental stage exposed to 40 °C using chlorophyll fluorescence technique (decreasing from mature to juvenile leaves), lower specific leaf area and higher leaf carotenoid and cytokinin (particularly BAP derivatives) concentration. In spite of lower heat stress tolerance and higher ash content, clone ‘Gigant' showed larger productivity than clone ‘Pannonia', suggesting potential of the latter for cultivation in much more stressful conditions. | Canadian poplar (Populus × canadensis Moench) clone | Production | Free combustible energy | Heat-stress tolerance | Chlorophyll a fluorescence | Cytokinin | Canadian poplar (Populus × canadensis Moench) clone, Production, Free combustible energy, Heat-stress tolerance, Chlorophyll a fluorescence, Cytokinin | ||||
| Chlorophyll fluorescence | FMS 2 | MDPI: Plants | Jesús Alberto Pérez-Romero | Universidad de Sevilla | Dpto. de Biología Vegetal y Ecología | Spain | 2020 | Importance of Physiological Traits Vulnerability in Determine Halophytes Tolerance to Salinity Excess: A Comparative Assessment in Atriplex halimus | Many halophytic physiological traits related to the tolerance of plants to salinity excess have been extensively studied, with a focus on biomass and/or gas exchange parameters. To gain a more complete understanding of whether salinity excess affects the physiological performance of halophytes, an experiment was performed using the halophyte Atriplex halimus L. as a model. A. halimus plants were subjected to two salinity treatments (171 and 513 mM NaCl) over 60 days in a controlled environment. After this period, dry biomass, specific stem conductivity, water potential at turgor loss point, osmotic potential, gas exchange parameters, and the fluorescence of chlorophyll a derived parameters were assessed in order to obtain knowledge about the differences in vulnerability that these parameters can show when subjected to salinity stress. Our results showed a decrease in belowground and aboveground biomass. The decrement in biomass seen at 513 mM NaCl was related to photosynthetic limitations and specific stem conductivity. Turgor loss point did not vary significantly with the increment of salinity. Therefore, the parameter that showed less vulnerability to saline stress was the turgor loss point, with only a 5% decrease, and the more vulnerable trait was the stem conductivity, with a reduction of nearly 50%. | halophyte | specific conductivity | turgor loss point | photosynthesis | chlorophyll fluorescence | halophyte, specific conductivity, turgor loss point, photosynthesis, chlorophyll fluorescence | |||||
| Chlorophyll content | CL-01 | Advances in Bioresearch | Ikram-ul-Haq | University of Sargodha | Department of Plant Breeding& Genetics | Pakistan | 2020 | Evaluation of potato (Solanum tuberosum L.) genotypes using different intercropping regimes | Potato (Solanum tuberosum) an important vegetable crop grown around the globe. Present study was conducted to ascertain the effect of intercropping on potato tuber yield and its components. Intercrop versus no-intercrop potato with berseem crop was examined to find out yield performance of potato tuber lines. Experiment was a completely randomized design in factorial arrangement in three replications. Factors considered were intercropping (2) and advanced lines. An overall positive effect of intercropping was observed on tuber yield of potatoes genotypes. Tuber yield increased (18%) with intercrop. Additionally, there was a successive increase reported in yield components. Correlation analysis between various morphological and yield components was computed under both regimes. Tuber weight per plant showed a significant correlation with all traits excluding chlorophyll contents, leaf area, number of tubers per plant and harvest index in the intercrop. Tuber weight per plant showed a negative correlation with berseem weight. The association analysis displayed tuber diameter as an important trait under both regimes. Leaf area may be used to improve tuber diameter due to its positive correlation with tuber diameter and high value of heritability. The trait could also be used to discriminate the genotypes before the plants reach maturity. | berseem | biomass | nodulation | leaf area | tuber diameter | tuber yield | berseem, biomass, nodulation, leaf area, tuber diameter, tuber yield | ||||
| Chlorophyll fluorescence | Handy PEA | Plant Biosystems | João Paulo Rodrigues Martins | Federal University of Esp ırito Santo | Plant Ecophysiology Laboratory | Brazil | 2020 | Morphophysiological responses of Aechmea blanchetiana (Bromeliaceae) to excess copper during in vitro culture | The use of plants as bioindicators can be effective for environmental monitoring, mainly related to heavy metals such as copper (Cu). In vitro conditions are more easily controlled, to enable isolating the stress factors that can interfere in plants’ responses. The aim was to investigate the morphophysiological responses of Aechmea blanchetiana submitted to excess Cu, and to verify the degree of tolerance and potential as a bioindicator of this species. Previously cultured shoots of A. blanchetiana were transferred to agar-solidified MS medium. After 60 days, the tank system was recreated, with the addition of stationary liquid MS medium with different concentrations of Cu (0, 25, 50 and 100 lM). After 90 days with excess Cu, anatomical analysis along with quantification of the contents of nutrients, photosynthetic pigments and chlorophyll a fluorescence were carried out. Alterations in the stomatal density and chlorenchyma thickness were observed in the plants grown with excess Cu. There was an increase in the Cu content in the plants in function of the Cu levels. However, the adjustments in the content of the other nutrients were essential for tolerance to excess Cu. Aechmea blanchetiana tolerates high Cu concentrations and has potential for use as a bioindicator. | Bromeliad | chlorophyll a fluorescence | environmental bioindicator plant anatomy | plant physiology | Bromeliad, chlorophyll a fluorescence, environmental bioindicator plant anatomy, plant physiology | ||||||
| Chlorophyll fluorescence | Pocket PEA | BIOLOGIA PLANTARUM | S.Y. ZHAO | Sichuan Agricultural University | Department of Grassland Science | China | 2020 | Mannose regulates water balance, leaf senescence, and genes related to stress tolerance in white clover under osmotic stress | Mannose (MAN), an important monosaccharide, contributes to coping with abiotic stresses in plants. Objectives of this study were to examine whether exogenous MAN (30 mM) could significantly increase drought tolerance and further to reveal MAN-regulated tolerance mechanism in white clover under osmotic stress induced by 18 % (m/v) polyethylene glycol 6000 for 10 d in controlled growth chambers. Results show that the application of MAN significanlty alleviated stress damage and the inhibition of growth and photosynthesis in white clover under osmotic stress. The MAN-induced increase in endogenous MAN content and the accumulation of organic osmolytes (proline and water soluble sugars) could be responsible for a lower osmotic potential (OP) in white clover. The exogenous application of MAN also enhanced antioxidant enzyme (superoxide dismutase, peroxidase, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase) activities and maintained ascorbic acid content in white clover during osmotic stress. As concern chlorophyll (Chl) metabolism, the MAN-treated plants showed significantly higher transcription of genes involved in Chl synthesis Mg-chelatase and protochlorophyllide reductase and lower transcription of pheophorbide a oxygenase and chlorophyllase related to Chl degradation and also a senescence associated gene 101 than untreated plants. In addition, the MAN application increased transcription of SK2-, Y2K-, and Y2SK-type dehydrin genes, and dehydrin b in leaves of white clover under osmotic stress. These results indicate that MAN plays important roles in drought tolerance not only acting as a compatible solute for OP but also delaying leaf senescence through enhancing antioxidant metabolism, decreasing Chl degradation, and increasing transcription of dehydrin genes contributing to enhanced drought tolerance in white clover. | antioxidants | dehydrins | osmotic potential | photosynthesis | senescence | Trifolium repens | antioxidants, dehydrins, osmotic potential, photosynthesis, senescence, Trifolium repens | ||||
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