毛竹光合作用对环境因子的季节响应

采用Li-6400测定毛竹光合作用对光照强度、CO2浓度、温度和湿度等环境因子响应的季节变化,结果表明:毛竹最大净光合速率、光补偿点、光饱和点、光合量子效率的年均值分别为7.30、19.15、1075mmol.m-2.s-1,0.032;最大净光合速率夏季>秋季>冬季>春季;春季的光补偿点最高,夏季次之,而秋季和冬季均较小;光饱和点与光合量子效率的季节变化均为秋季>夏季>冬季>春季。毛竹CO2补偿点、CO2饱和点、羧化效率的年均值分别为73.52、1500μmol.mol-1,0.033。CO2补偿点春季>冬季>秋季>夏季;CO2饱和点春季>秋季>夏季>冬季;羧化效率夏季>秋季>冬季>春季。毛竹光合最适温度均在20～30℃,光合最适温度在春、秋季与实验前3天最高气温的平均值十分接近,而夏、冬季与测定前10天的最高气温平均值较为接近,光合最适温度在春、秋两季相当,夏季稍高,冬季最低。光合最适湿度为40%～65%,季节变化趋势:秋季>夏季>冬季>春季。总体而言,毛竹光合作用对环境因子的季节响应与环境因子的季节变化、叶片的生理活性密切相关。

Seasonal photosynthetic responses of Phyllostachys edulis to environmental factors

By using Li-6400,the seasonal photosynthetic response of Phyllostachys edulis to light intensity,CO2 concentration,temperature and humidity were determined.The main results are as follows:the annual average of maximal net photosynthetic rate(Pmax),light compensate point(LCP),light saturate point(LSP),and apparent quantum yield(AQY)for P.edulis are respectively 7.30,19.15,1 075 mmol·m-2·s-1 and 0.032.The seasonal photosynthetic variation tendency of P.edulis to light intensity were summer>autumn>winter>spring for Pmax,spring>summer>winter>autumn for LCP,and autumn>summer>winter>spring for LSP and AQY.The annual average of CO2 compensate point(CCP),CO2 saturate point(CSP)and carboxylase efficiency(CE)for P.edulis are respectively 73.52,1 500 μmol·mol-1 and 0.033.The seasonal photosynthetic variation tendency of P.edulis to CO2 concentration were spring>winter>autumn>summer for LCP,spring>autumn>summer>winter for CCP,and summer>autumn>winter>spring for CE.The optimal temperature for photosynthesis of P.edulis ranges from 20 to 30 ℃,equivalent in spring and autumn,higher in summer and lowest in winter.It is close to the average of three day's highest temperature before test in spring and autumn,and close to the average of ten day's highest temperature before test in summer and winter.The optimal humidity for photosynthesis of P.edulis ranges from 40% to 65%,its seasonal variation tendency is autumn>summer>winter>spring.On the whole,the seasonal photosynthetic responses of P.edulisto environmental factors were closely related with seasonal change of the environment and the physiological activity of leaves.