FIGURE 2.
Effect of tAPX silencing on cellular redox state and photosynthesis under NL. Seventeen-day-old IS-GUS-2-17 and IS-tAPX-19-23 plants were sprayed with a 100 μm estrogen and kept under NL for indicated period. A, H2O2 was detected by DAB staining. A detached leaf at 48 h after the estrogen treatment was vacuum-infiltrated with DAB solution and incubated under NL for 3 h. The leaf was then decolorized by incubation in 70% ethanol. The same results were obtained in five independent experiments. Results of representative leaves were photographed. B, total proteins were extracted from leaves of IS-GUS-2-17 and IS-tAPX-19-23 plants. Oxidized proteins were detected using a protein gel blot assay with an OxyBlot protein oxidation kit as described under “Experimental Procedures.” C and D, levels of AsA, dehydroascorbate (DHA), GSH, and GSSG were measured. White bars (showing dehydroascorbate and GSSG) are started on top of gray bars (showing AsA and GSH). E and F, quantum yields of photosystem II, Fv/Fm and ΦPSII, were also measured using a Closed FluorCam 800MF as described under “Experimental Procedures.”