Four rice (Oryza sativa L.) cultivars “IR72”, “Tesanai 2”, “Guichao 2” and “IIyou 4480” were grown in two plastic house (15 m×3 m) with 35 μmol/mol and 60 μmol/mol CO2 concentration which was controlled by computer. As compared with rice at ambient 35 μmol/mol CO2, the changes in photosynthetic rate at elevated CO2 showed up-regulation (“IR72” and “Tesanai 2”), stable (unchanged) in “Guichao 2” and down-regulation type (“IIyou 4480”). Growth rate, panicle weight, integrated water use efficiency (WUE) calculated from Δ13C and the capacity of scavenging DPPH· (1,1-diphenyl-2-picrylhydrazyl) free radical were increased at elevated CO2. An increment in total biomass was observed in three cultivars by elevated CO2, with the exception of “IIyou 4480”. Ratios of panicle weight/total biomass were altered to different extents in tested cultivars by elevated CO2. When leaf segments were subjected to PEG osmotic stress, the electrolyte leakage rate from leaves grown at elevated CO2 was less than that at 35 μmol/mol CO2. Those intraspecific variations of rice imply a possibility for selecting cultivars with maximal productivity and high tolerance to stresses adapted to elevated CO2 in the future.
水稻的光合作用、生长、碳同位素分辨作用及抗渗透胁迫性对
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