Fig. 5.

PSII photochemical efficiency and CO₂ fixation in Arabidopsis wild-type and mutant lines. Plants were either grown under standard long-day conditions (control), with continuous light (light), or grown as in control conditions and then subjected to 3 d of continuous darkness (darkness). Then six leaves from different plants of wild-type and mutant lines were used for determination of the initial PSII photochemical efficiency (F_v/F_m) (A) and CO₂ fixation rate, which was determined as described in the Materials and methods at a light intensity of 1000 μE m⁻² s⁻¹ (B). Values are represented as the means ±SE. Letters indicate significance of difference (P ≤0.05) as determined by Tukey's multiple range test.