Whole-chain (WC), PSII, and PSI reactions
Thylakoid membranes were isolated in isolation buffer containing 0.01M Tris and 1 mM EDTA (pH 7.5). The homogenate was centrifuged at 12,000xg for 5 min and the pellet containing thylakoid membrane was suspended in suspension buffer containing 0.4 M sorbitol, 0.05 M Tris (pH 7.5), 1 mM MgCl2 and 1 mM EDTA (see Sood et al., 2005; Gupta and Tripathy, 2010). Using thylakoid membranes isolated from VC and CAx plants, we monitored (a) the light-saturated whole chain (WC) electron transport, from water to methyl viologen [MV]); (b) the partial reaction of PSII from water to phenylenediamine [PD], and (c) that of PSI from ascorbate/ dichlorophenol-indophenol to MV, using a Clark type oxygen electrode.