云锦杜鹃幼树光合特性及其与生态因子的关系

A Study on Photosynthesis and Its Relation to Ecological Factors of Rhododendron Fortunei Seedling

自然条件下,对云锦杜鹃光合作用日进程进行了测试,研究结果表明:(1)夏季晴天云锦杜鹃幼树叶片净光合速率日进程曲线为"双峰"型,胞间CO2浓度的日进程基本与净光合速率相反,中午胞间CO2浓度增高表明净光合速率午间降低主要受非气孔限制因素的影响;(2)应用逐步多元回归方法,得到云锦杜鹃净光合速率日变化的最优方程为:Y=28.3043+0.0028X1-0.2821X2-0.8538X4+0.0414 X5。偏相关分析和通径分析表明,光合有效辐射、空气CO2浓度、气温和叶温与净光合速率的日变化有着密切关系,是影响净光合速率的直接主要因子。

The photosynthetic diurnal variations in leaves of Rhododendron fortunei seedling under natural conditions had been studied. The results were as follows: 1) In clear summer days, the diurnal variations of net photosynthetic rates (Pn) of Rhododendron fortunei were 'double-peaked' curves. The diurnal variations of internal CO2 concentration (Ci) were just opposite to Pn. The increasing of Ci at midday showed that the decreasing of Pn was related to non-stoma restriction factors. 2) By the method of stepwise multi-regression, the most excellent equation of the diurnal variation of Pn was attained as follows: Y=28.3043+0.0028X1-0.2821X2-0.8538 X4 +0.0414 X5. The analysis of partial correlation and path coefficient on Pn and factors showed that the diurnal variation of Pn had closer relations to the primary direct factors including photosynthetic active radiation (PAR) , air CO2 concentration (Ca) , ambient temperature (Ta) and leaf temperature (T1).