Figure 5.

Superoxide generated by photosystems of PsbS-KO and wild-type rice. (a) PSII (BBY) particles. (b) Photosystem II complex isolated along sucrose gradient. (c) Photosystem I complex isolated along sucrose gradient. (d) Thylakoids with PSII-driven superoxide production. (e) Thylakoids with PSI-driven superoxide production. In (a), fluorescence emission of dihydroethidium (25 μM) at 590 nm was used to detect production. In (b-e), absorbance of NBT (15 μM) at 560 nm was used to detect production. Samples were illuminated at 700 μmol photons m⁻² s⁻¹ for photoinhibition at room temperature. Each sample contained 10 μg chlorophyll per mL. Each point represents mean of at least 4 experiments (SD indicated by bar) and the asterisks denote the results that were significantly different from those in the wild type (*P < 0.05). The statistical significance was evaluated using the Student’s t -test.