Table 2. Maximum Quantum Efficiency of PSII (F_v/F_m).

Genotype	Control Fv/Fm	12-h High-Light Fv/Fm
Wild type	0.836 ± 0.002	0.693 ± 0.083
cry1	0.837 ± 0.005	0.374 ± 0.065*
zml2-1	0.835 ± 0.003	0.569 ± 0.025*
zml2-2	0.821 ± 0.002	0.556 ± 0.033*
zml1	0.836 ± 0.004	0.397 ± 0.109*
zim	0.837 ± 0.001	0.657 ± 0.027

F_v/F_m was estimated before and after exposure to 12 h of white light at 1000 μmol of photons m⁻² s⁻¹ in 5-week-old plants of the wild type and cry1, zml2-1, zml2-2, zml1, and zim mutants. Measurements were made in humidified air. Each point is the mean ± sd of nine leaves from at least three individual plants after 30 min of dark acclimation. The F_v/F_m was significantly different from the wild type in the cry1, zml2, and zml1 mutants following high light exposure (asterisk) according to the Student’s t test (P < 0.05).