南方型杨树“中石2”光合生理生态因子的动态变化分析

Effect of Ecophysiology Factors on Dynamic Changes of Photosynthesis of Poplar "Zhongshi 2" in South of China

对南方杨树主栽品种"中石2"(Populus deltoides CL.′Zhongshi 2′)幼树的净光合速率及生理生态因子的动态变化进行了分析.结果表明:相对湿度与净光合速率的关系紧密.在高光强、高湿度的环境,杨树"中石2"生长良好,净光合速率较高;随环境因子的变化,至湿度降低的环境,杨树净光合速率有所降低;而至9月份杨树在一天中生理生态因子的变化较复杂,环境湿度低,净光合速率最小.在集约栽培过程中,应注意适当的栽植密度,同时进行喷雾,增加环境湿度,可以达到最适的生长环境条件.通过拟合,得到单因子动态变化与净光合速率变化的二项式回归模型,相关性达极显著和显著水平.应用多因子及互作相逐步回归分析,构建最优回归模型:Y=1.968 1+19.096 3X4-0.008 0X6+0.0001X1X2-0.008 5X1X4(PAR-X1、RH-X2、Gs-X4、Ci-X6、Pn-Y),具有较强的预测能力.

This paper reports the dynamic changes of net photosynthetic rate （Pn） and its response to ecophysiology-factors of Poplar＂Zhongshi 2＂ （ Populus deltoides CL. ＇Zhongshi 2＇ ） in South of China. It is shown that relative humidity （RH） was important for Pn. Poplar grew well and the Pn was fairly high in high photosynthetically active radiation （PAR） and high RH. The observed Pn decreased with the decrease of RH. However, the change of the environment factors in daily course in September was complicated, and the observed Pn decreased rapidly while RH decreased slightly. In the process of collective planting, cultivator should take into account the density of plants and proper water spraying is needed to increase RH . The results also show that single ecophysiology-factor was significantly and positively correlated with Pn and the relation could be fitted to a polynomial. The best model of the dynamic change of Pn is obtained by the method of stepwise multiple regression as follows： Y=1. 9681＋19. 096 3X4-0. 008 0Z6＋0. 000 1 X1X2-0. 008 5 X1X4（where X1, X2, X4, X6 and Y represent PAR,RH,G5.Ci and Pn respectively）.