垂丝海棠和木瓜海棠的气体交换参数对光的响应

Response of Gas-Exchange Parameters to Light Intensity of Malus halliana and Chaenomeles cathayensis

以垂丝海棠和木瓜海棠为实验材料，用CIRAS-2型光合仪测定并计算垂丝海棠和木瓜海棠光合速率（Pn）、蒸腾速率（E）、胞间（CO2）、浓度（Ci）、气孔导度（Gs）、光饱和点、光补偿点、表观量子效率等光合参数，对两者的光合特性进行比较。结果表明，随着光强的升高，垂丝海棠和木瓜海棠的净光合速率和气孔导度都随着光强的增强而升高；垂丝海棠光补偿点较低、光饱合点较高，表明垂丝海棠对强光的适应性较强；垂丝海棠的表观量子效率比木瓜海棠的高，说明垂丝海棠叶片转化光能的效率高于木瓜海棠，并且对弱光的利用能力较强。这些数据为垂丝海棠和木瓜海棠在园林绿化中的合理配置与栽培提供了理论依据。

With Malus halliana and Chaenomeles cathayensis as materials, the photosynthetic rate （Pn）, transpiration rate （E）, intercellular （CO2） concentartion （Ci）, stomatal conductance （Gs）, light saturation point, light compensation point, apparent quantum yield and other photosynthetic parameters of the two plants were measured by CIRAS-2 photosynthetic equipment and analyzed, their photosynthetic characteristics were compared. The results showed that the net photosynthetic rates and stomatal conductances of both Malus halliana and Chaenomeles cathayensis increased as the light intensity rised. The higher light saturation point and the lower light compensation point of Malus halliana, suggested that they had a strong adaptability for high light intensity. The higher apparent quantum yield ofMalus halliana implied that their efficiency of light energy conversion was high and low light intensity could be used effectively in their leaves. These data might provide the theoretic basis for the reasonable allocation and cultivation of Malus halliana and Chaenomeles cathayensis in the landscape.