Western blotting
Western blotting was used to quantify OEC peripheral proteins PsbO, PsbP, PsbQ, as well as the terminal enzyme l-galactono-1,4-lactone dehydrogenase (GLDH) of AsA biosynthesis and PSII RC proteins D1, CP43. GLDH located in mitochondrion was detected using the proteins in leaves which were isolated as previously described (Jorrin-Novo, 2014). The other proteins located in photosynthetic membranes were detected using chloroplasts. To determine the loading quantity of sample, the protein and chlorophyll contents were measured as previously published (Porra et al., 1989). Solubilized materials were fractionated using sodium dodecyl sulfate–polyacrylamide gel electrophoresis. Western blot assays with antibodies (Agrisera, Sweden) were performed as previously described (Fristedt et al., 2009). As equal loading control, the Rubisco large subunit (RbcL) antibody was used. The chemiluminescent bands visualized on a Gel Doc XR+ system (Bio-Rad, CA, USA) were quantified with the program Quantity One software. For each case, the density of the samples was standardized based on the RbcL density.