Authors: Jihu Su Yungang Shen
Publish Date: 2013/08/30
Volume: 48, Issue: 7, Pages: 652-657
Abstract
Change of proton gradient across thylakoid membrane in soybean leaves was studied with millisecond delayed light emission msDLE during the course of state transitions which were indicated by the chlorophyll fluorescence at room temperature and 77 K When darkadapted leaves were induced to state I with farred light F m/F o F 685/F 735 and the intensity of fast phase of msDLE were affected slightly However during the induction to state II with red light both F m/F o and F 685/F 735 decreased immediately and the former were quicker than the latter In this interval the intensity of fast phase of msDLE increased to a maximum and then decreased to a lower value during the transition to state II Nigericin an uncoupler which eliminates the proton gradient across thylakoid membrane inhibited the increase in the intensity of fast phase of msDLE during the transition to state II Another uncoupler valinomycin which eliminates the membrane potential did not affect the changes of the intensity of fast phase These results suggest that the prompt increase in the intensity of fast phase of msDLE at the beginning of transitions to state II is correlated mainly with the proton gradient released from water oxidation in photosystem II
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