Fig. 3

Changes of photochemical efficiency of two maize varieties under drought stress. A Drought induced changes in PSII and PSI parameters of SD609. Y(II), the effective quantum yield of PSII photochemistry; Y(NPQ), the quantum yield of PSII regulated nonphotochemical energy dissipation; Y(NO), the quantum yield of nonregulated nonphotochemical energy dissipation; Y(I), the effective quantum yield of PSI photochemistry; Y(NA), the nonphotochemical quantum yield of the PSI acceptor side. Y(ND), the nonphotochemical quantum yield of the PSI donor side. B Drought induced changes in PSII and PSI parameters of SD902. C ETRI, electron transport rate through PSI. D ETRII, electron transport rate through PSII. E CEF activity of SD609 and SD902 under moderate drought stress. Each parameter represents means ± standard errors of three replicates. The different letters above the columns indicate significant difference at P < 0.05 level between treatments