Additional dark-adaptation leafclips for use with FMS fluorometers. These should be used when dark-adaptation of the sample (or measurement in the absence of light), is required before or during the experiment. The leafclips can be attached to samples independently prior to measurements to facilitate adequate dark-adaptation time for the sample being measured without hindering throughput.
Dark-adaptation leafclips can be used for a wide variety of different samples such as broad-leaf species (including Arabidopsis), grasses and needle species.
Dark-adaptation leafclips are constructed from 3D printed nylon. To dark-adapt the sample, a stainless steel shutter plate in the upper section of the clip is slid forward, covering the sample, and effectively preventing ambient light from reaching the leaf. During measurements, the sampling end of the fibre-optic cable is inserted into the fibre receptor on the upper section of the leafclip and securely fastened using the thumb-screw. Before taking measurements, the shutter is retracted to the open position, exposing the dark-adapted sample to the fibre-optic light source.
The sample rests on a foam pad whilst in the clip in order to minimise damage to the structure of the sample.
During dark adaptation, all the reaction centres are fully oxidised and available for photochemistry and any chlorophyll fluorescence yield is quenched. This process takes a variable amount of time and depends upon plant species, light history prior to the dark transition and whether or not the plant is stressed. Typically, 15 – 20 minutes may be required to dark adapt effectively. In order to reduce waiting time before measurement, a number of leaves may be dark adapted simultaneously using several leafclips.