PSII activity and levels of PSII core subunits are more sensitive to HL intensities or low temperatures in TEF30-amiRNA cells than in control cells. A, cw15-325 control (Con) and TEF30-amiRNA strains were photoinhibited (PI) for 60 min at 1,800 μmol photons m–2 s–1, then allowed to recover at 30 μmol photons m–2 s–1. PSII fluorescence was measured by pulse amplitude-modulated fluorometry. Values represent means from three biological replicates, and error bars indicate sd. B, Control and TEF30-amiRNA #1.48 cells in the cw15-325 strain background were exposed to high PFDs (HL) of approximately 800 µmol photons m−2 s−1 for 6 h. Whole-cell proteins corresponding to 0.2, 1, or 2 µg of chlorophyll (depending on the antiserum used) were separated on 10% or 14% SDS-polyacrylamide gels and analyzed by immunoblotting. C, Control and TEF30-amiRNA #2.48 cells in the cw15-325 strain background were grown at a PFD of approximately 30 μmol photons m–2 s–1 and then shifted from a growth temperature of 25°C to 10°C for 18 h. Samples were analyzed as in B.