Figure 4.

Evidence for a dominant role of the qE component of NPQ during N deprivation based on analysis of the various mutants. Representative Chl fluorescence traces show the wild type (WT; top left), npq4 (top right), stt7 (bottom left), and npq1 (bottom right) following 3 d of N deprivation. Black bars at the top of the graphs indicate dark periods, and white bars indicate light periods (HL; 750 µmol photons m⁻² s⁻¹). NPQ values (average from biological replicates) generated during HL are indicated above the F_m′ fluorescence peaks near the end of the light period. All Chl fluorescence traces were normalized to F₀. Arrows indicate activation of the measuring light (ML ON). a.u., Arbitrary units.