5℃夜间低温处理温室栽培红海榄 (Rhizophorastylosa)和银叶树 (Heritieralittoralis)幼苗 ,白天 2 0℃室温分别恢复 1h和 4h ,测定功能叶的净光合速率、气孔导度、胞间CO2 浓度、蒸腾速率和叶绿素含量。结果表明 :夜间低温明显降低红海榄和银叶树的净光合速率、气孔导度、蒸腾速率和水分利用率 ,促进胞间CO2 浓度增加 ,而叶绿素含量变化不大。白天定温恢复时间增长 ,净光合速率、气孔导度和蒸腾速率回升 ,胞间CO2 浓度下降 ,红树幼苗对低温有一定的适应能力。低温处理 2d ,红海榄叶净光合速率的抑制程度大于 1d处理 ,而银叶树叶净光合速率的抑制程度则有所减轻。两种红树叶气孔导度与净光合速率和蒸腾速率均呈线性关系 ,气孔导度是控制叶片光合成和蒸腾水分丢失动态平衡的主要因素。With 5℃ Night temperature treatments for 13h each day,net photosynthetic rate(Pn),stomata conductance(Cs),inter-cellularCO_2 concentration(Ci),transpiration rate(Tr),water use efficiency (WUE) and chlorophyll content(Ch1) of one year Rhizophora stylosa and Heritiera littoralis seedings Leaves were measured after 1h and 4h recovery at greenhouse temperature.The results showed that Pn,Cs,Tr and WUE of Rhizophora stylosa and Heritera littoralis seedings leaves were significantly inhibited by low night temperature treatments but Ci were raised and Ch1. had litter changes. Pn?Cs and Tr of two mangrove species would rise as recovering times increased, which indicated that both Rhizophora stylosa and Heritiere littoralis seedling had some adaptation to low night temperature,when low night temperature treatment days increased ,Pn and Tr of Rhizophora stylosa were more inhibited than Heritiera littoralis. A linear relationship existed between Pn and Cs and between Tr and Cs,respectively,which showed that carbon gain by photosynthesis and water loss by transpiration were inhibited at the same time.It is suggested that Cs was the main factor to control dynamic balance between carbon gain process and water loss process
