NPQ analysis of wild-type and mutant genotypes. (A) Kinetics of NPQ induction and relaxation were recorded with a pulse amplitude modulated fluorometer. Chlorophyll fluorescence was measured in dark-adapted leaves, during 7 min of illumination at 1000 μmol photons m-2 s-1 followed by 18 min of dark relaxation. (B) Amplitude of the reversible energy dissipation (qE). (B, C) Extent of feed-back de-excitation (qE, panel B) and photoinhibitory quenching (qI, panel C) determined at a series of irradiances as a difference between NPQ values upon illumination and following 15 min dark relaxation. Symbols and error bars show means ± SD (n = 4).