松嫩草地全叶马兰夏季与秋季光合及蒸腾作用的比较

在生长季晴天条件下，夏季和秋季松嫩草地全叶马兰的光合，蒸腾作用的日变化均为双峰曲线，但不同季节有所差异，夏季日均净光合速率与蒸腾速率均高于秋季，光合和蒸腾作用与环境因子的植物内部因子之间有密切关系。分析表明，叶片净光合速率与有效光辐射呈极显著相关，与气孔阻力，胞间CO2呈负相关；蒸腾速率与有效光辐射呈极显著相关，与叶温，饱和差呈正相关，与气孔阻力，胞间CO2浓度呈负相关，有效光辐射是影响光合和蒸腾作用诸因子中的主导因子，而气孔阻力变化则在调节光合和蒸腾中起着重要作用，蒸腾速率午降主要由于光辐射强，叶温高，湿度低，植物体缺水，气孔部分关闭所致。

A comparative study on photosynthesis and transpiration of Kelimeris integrifolia in summer and autumn on Songnen grasslands of China

The diurnal changes in photosynthesis and transpiration of Kelimeris integrifolia in Summer and Autumn on Songnen grasslands were characterized as a two peak curve,but with some differences between two seasons. It was shown that environmental conditions and plant internal factors had a strong effects on plant photosynthesis and transpiration. The net photosynthetic and transpiration rates of the leaves were positively correlated to photosynthetically active radiation ( P <0.01),and negatively correlated to stomatal resistance as well as intercellular CO 2 concentration ( P <0.05). The transpiration rate was positively correlated to leaf temperature and water saturation deficit of the air. Among the above factors,photosynthesis active radiation was the dominant factor,and stomatal resistance also played an important role in plant photosynthesis and transpiration.