Fig. 2.

The ntrc-srx double mutant and the ntrc mutant show similar phenotypes. (A) Chlorophylls a and b were extracted from rosette leaves of Arabidopsis plants that were grown for 30 days under a long-day photoperiod. Determinations were performed on at least three independent biological samples with similar results. Chlorophyll determination was performed twice per sample and mean values ± SE are shown. Letters above bars indicate significant differences (P < 0.05) according to Tukey’s multiple range test. (B) Photochemical efficiency of PSII, Fv/Fm, was determined on 6–8 leaves of the different lines grown under long-day conditions (grey bars) or subjected to a period of 3 days of continuous darkness (black bars). The experiment was performed three times with similar results and mean values ± SE are shown. Letters above bars indicate significant differences (P < 0.05) as determined by Tukey’s multiple range test comparing the four Arabidopsis genotypes for each condition.