A B 1000 Light intensity (µmol m-2 s-1) 3.0 2.5 2.0 NPQ 1.5 +MV +Nig Light intensity (µmol m-2 s-1) 3.0 2.5 2.0 NPQ 1.5 +MV +Nig 1.0 Control 0.5 0.0 5 10 15 20 25 Duration of incubation (min) B 0.9 Control (-Cm) +Cm 0.8 +MV +Nig 0.7 0.6 0.5 Control Fv/Fm 0.4 Control 0.3 0.2 0.1 1 2 3 1 2 3 Duration of incubation in light (h) Supplemental Figure 2. Effect of methyl viologen and nigericin on NPQ (A) and photoinhibition (B) in the pgr5 mutants. Leaf discs (78.5 mm2) from the pgr5 mutants were vacuum infiltrated with 1 mM nigericin (Nig) or 200 μM methyl viologen (MV) and exposed to light at 1000 µmol photons m-2 s-1. (A) Induction of NPQ. (B) Leaf discs were exposed to light after vacuum infiltration of 1 mM chloramphenicol (Cm) or in its absence (Control). The maximum quantum yield of PSII (Fv/Fm) was measured after dark incubation for 15 min. In A and B, the values are mean ± SD (bars) of results from three independent experiments.