Figure 2.
Analysis of room temperature Chl fluorescence during photosynthesis in wild-type and mutant plants. A, Dependence of the linear electron flow (LEF) on light intensity was measured in wild-type and mutant leaves. ETR was calculated as ΦPSII·PAR·Aleaf·fractionPSII (see “Materials and Methods” for details). B, Amplitude of qL measured at different light intensities. qL reflects the redox state of the primary electron acceptor QA, thus the fraction of open PSII centers. C, Dependence of qE, the rapidly reversible component of NPQ, on light intensity. Data are expressed as means ± sd (n = 4). D, Amplitude of light-dependent quenching of 9-AA fluorescence, measured at different light intensities on intact chloroplasts. 9-AA fluorescence quenching is induced by actinic illumination of chloroplasts and reflects the amplitude of transthylakoid ΔpH buildup. Values that are significantly different (P < 0.05) from the wild type are marked with an asterisk (*).