FIGURE 6.

Photosynthetic performance of the wild-type and ZmpsbA-transgenic plants under drought stress. Four weeks old WT and transgenic plants were drought-stressed for 7 days, and then the leaf samples were taken to determine photosynthetic gas exchange and chlorophyll fluorescence parameters. (A) Net photosynthetic rate; (B) Stomatal conductance; (C) Intercellular CO₂ concentration; (D) Maximal efficiency of PSII photochemistry (Fv/Fm); (E) Actual efficacy of PSII (ΦPSII). Data are means ± SE calculated from three replicates. Different letters indicate a significant difference between the WT and both transgenic lines (ANOVA; P < 0.05). Three biological experiments were performed, which produced similar results.