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CO2浓度增高的响应

摘要

四个水稻(Oryza sativa L.)品种"IR72"、"特三矮2号"、"桂朝2号"和"Ⅱ优4480"在田间栽于含35 μmol/mol 和60 μmol/mol CO2的塑料大棚中,自然光照.高浓度CO2下供试水稻品种的光合速率变化表现为提高型("IR72"、"特三矮2号")、稳定型("桂朝2号"的Pn几无变化)和下调型("Ⅱ优4480").生长速率、穗重、由Δ13C计算而得的长期水分利用效率和清除DPPH@自由基的能力皆增加.除"Ⅱ优4480"外,其他3个品种明显增高总生物量.供试品种的穗重/总生物量比不同程度地受到高浓度CO2的改变.叶片段经PEG渗透胁迫后,不同的生长于高浓度CO2者的电解质渗漏率较小.结果表明高浓度CO2可改变水稻的光合作用和水分关系特性,品种间不同的响应显示了选育适于未来高浓度CO2下具有高产和抗逆性品种的可能性.%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 CO2 concentration which was controlled by computer. As compared with rice at ambient 35 μmol/mol CO2, the changes in photosynthetic rate at elevated CO2 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 Δ13C and the capacity of scavenging DPPH· (1,1-diphenyl-2-picrylhydrazyl) free radical were increased at elevated CO2. An increment in total biomass was observed in three cultivars by elevated CO2, with the exception of “Iiyou 4480”. Ratios of panicle weight/total biomass were altered to different extents in tested cultivars by elevated CO2. When leaf segments were subjected to PEG osmotic stress, the electrolyte leakage rate from leaves grown at elevated CO2 was less than that at 35 μmol/mol CO2. Those intraspecific variations of rice imply a possibility for selecting cultivars with maximal productivity and high tolerance to stresses adapted to elevated CO2 in the future.