Energy-dependent chlorophyll fluorescence quenching in chloroplasts correlated with quantum yield of photosynthesis

Abstract

Chlorophyll a fluorescence quenching was studied in intact, CO2 fixing chloroplasts isolated from spinach. Energy-dependent quenching (qE), which is correlated with the light-induced proton gradient across thethylakoid membrane presumably reflects an increase in the rate-constant of thermal dissipation of excitation energy in the photosynthetic pigment system. The extent of qE was found to be linearly related to the decrease of quantum yield o f photosynthesis. Wesuggest that this relationship indicates a dynamic property of the membrane to adjust thermal dissipation of absorbed light energy to the energy requirement of photosynthesis. © 1987, Walter de Gruyter. All rights reserved.