Abstract: To analysis the correlation between net photosynthetic rate and ecological factors, using the methods of stepwise regression and analysis of path is much better than correlation analysis of duality variable.By the methods of stepwise regression and analysis of path, this paper studied the diurnal changes of zhongjia8, a crossbreed from Occident Poplar, during early summer and autumn.The results indicated that the diurnal changes of Pn showed a single-peak curve in early summer, the major factor affecting it was PAR (X₁), and PAR had extremely significant correlation with Pn.The optimum equation of Pn was attained as follows:Y=17.8271+0.0108 X₁-0.2185 X₂(multiple correlated coefficient R=0.9954, F=215.4439, significance level p=0.0001, Pn-Y, PAR-X₁, RH-X₂).But in September, Pn showed a two-peak curve, the major factor affecting it was Ca(X₄).The optimum equation was attained as follows:Y=5.2915-0.0030X₁+0.3414X₃-0.0216X₄ (multiple correlated coefficient R=0.8962, F=4.0823, significance level p=0.1391, Pn-Y, PAR-X₁, RH-X₂, Tleaf-X₃, Ca-X₄).

Key words: Populus deltoides CL.‘Zhongjia 8’, photosynthetic rate, ecological factor, stepwise multiple regression, analysis of path

摘要： 本文利用DPS数据处理系统,采用多元逐步回归及通径分析方法,得出欧美杨杂交种‘中嘉8’(Populus deltoides CL.‘Zhongjia 8’)在6月和9月净光合速率与生态因子的关系。结果表明,‘中嘉8’在6月晴天净光合速率呈单峰曲线,其最主要影响因子为光合有效辐射PAR(X₁),二者极显著相关,净光合速率日变化最优方程为:Y=17.8271+0.0108X₁-0.2185X₂;9月晴天净光合速率呈双峰曲线,影响光合速率日变化的最主要因子为空气CO₂浓度Ca(X₄),净光合速率日变化最优方程为:Y=5.2915-0.0030X₁+0.3414X₃-0.0216X₄。统计分析表明,采用多元逐步回归及通径分析应用于统计光合速率与生态因子的相关关系,较二元变量的相关分析更为科学合理。

关键词: 欧美杨杂交种&lsquo, 中嘉8&rsquo, 光合速率, 生态因子, 多元逐步回归, 通径分析