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Updated: May 19, 2026

High-Throughput Analysis of Non-Photochemical Quenching in Crops Using Pulse Amplitude Modulated Chlorophyll Fluorometry
Published on: July 6, 2022
In photoinhibited photosystem II particles pheophytin photoreduction remains unimpaired
S I Allakhverdiev1, E Šetliková, V V Klimov
1Institute of Soil Science and Photosynthesis, USSR Academy of Sciences, 142292 Pushchino, USSR.
Abstract:
Oxygen-evolving photosystem II particles (DT 20) isolated from pea chloroplasts by digitonin-Triton X-100 fractionation were photoinhibited with 150 W. m(-2) white light, at 20°C under three conditions: aerobic, anaerobic and strongly reducing (E(h) poised to approx. -250 mV with dithionite). Hill reaction rate (H (20) + BQ)and variable fluorescence (Fv) declined in parallel in all three cases with shortening half times: 30, 10 and 2.5 min, respectively. Light-induced absorbance changes at 685 nm characteristic of reversible photo accumulation of reduced pheophytin (& z -2.50 mV) remained essentially unchanged. We conclude that the three types of photoinhibitory treatment do not impair the separation of charges between chlorophyll P-680 and pheophytin in the photosystem II reaction center.
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