Figure 3.

Photoinhibition of PSII and recovery kinetics of high light-treated wild-type (WT) and mutant leaves. A, Loss of quantum yield (F_v/F_m) with and without CAP after exposition to 1,200 μE m⁻² s⁻¹ for 4 h. F_v/F_m ratios are expressed relative to the initial values before starting the experiment in the wild type (F_v/F_m approximately 0.82) and mutants (F_v/F_m approximately 0.68), respectively (see data for independent transformants in Supplemental Fig. S1C). B, PSII recovery from photoinhibition of wild-type and ΔpsbTc-1 mutant leaves exposed to photoinhibition at 1,200 μE m⁻² s⁻¹ until a F_v/F_m ratio of 0.17 was reached by each sample. PSII recovery was followed by further incubation of the samples at 3 μE m⁻² s⁻¹ for the times indicated. Total recovery after 6 h is depicted as the ratio F_v/F_m as a percentage of the original F_v/F_m in the wild type and mutant. Error bars in A and B represent sd of at least three independent experiments. C, Immunoblot analysis of the wild type and ΔpsbTc-1 with D1-specific antibodies before and 3 h after photoinhibition (3 h) at 1,200 μE m⁻² s⁻¹ with (+) and without (−) CAP. Five micrograms of chlorophyll was loaded, and equal loading was routinely checked either by immunoblot analysis with antibodies raised against cytochrome b₆ or by gel staining.