Figure 5.

Changes of ion leakage and PSII activity in the MV/light-treated leaf disks of control, P1#11, P1#14, and P1#18 plants. Plants were grown on soil in growth cabinets in a 16/8-h photoperiod at 280 μmol photons m⁻² s⁻¹, with day/night temperatures of 22°C/18°C to the ninth to tenth leaf stage. Leaves of similar size and age (fifth to seventh leaf position from the bottom) were used. Leaf discs were let absorb MV as in “Materials and Methods,” and were then illuminated for 2 h at 25°C with white light of 280 μmol m⁻² s⁻¹. After another 20 h dark incubation at 28°C, the conductivity of the floating solution for ion leakage (top section) and F_v/F_m for PSII activity (bottom section) were determined. Data are presented as mean of the following number of plants ± se: for P1#11 and control (left column), 12 plants; for P1#14 versus control (middle column), 34 plants; for P1#18 versus control (right column), 18 plants (0 and 0.4 μm MV) or 12 plants (0.2 μm MV). Three leaf discs per plant were used for each treatment. Asterisks indicate significant differences as in Figure 4.