Figure 2.

Characterization of Detailed Chlorophyll Fluorescence in the Wild Type and hhl1 Mutants.

(A) Light-response curves of PSII quantum yield and ETR in wild-type and hhl1 mutants. The measurements were performed at the following light intensities: 0, 81, 145, 186, 281, 335, 461, 701, and 926 μmol photons m⁻² s⁻¹. HL, high light.

(B) Time courses for induction and relaxation of NPQ before and after 3-h high-light treatment. Actinic light (500 μmol photons m⁻² s⁻¹) was switched on at time zero, and plants were left in the dark after 12 min.

(C) Recovery of maximal photochemical efficiency of PSII after photoinhibition. Maximal photochemical efficiency of PSII (F_v/F_m) during recovery period at irradiance of 100 μmol photons m⁻² s⁻¹ was measured by following the photoinhibition treatment to 50% of the initial F_v/F_m values. Data for wild-type (Col-0), hhl1-1, and hhl1-2 plants are presented as mean ± se. Five biological replicates were performed, and similar results were obtained.