田间珊瑚树净光合速率及生态因子的日变化

Diurnal Variation of Net Photosynthetic Rate and Ecological Factors of Viburnum odoratissimum in the Field

自然条件下 ,对珊瑚树叶片光合作用日进程的研究结果表明 :夏季晴天珊瑚树阳叶净光合速率日进程曲线为“双峰”型 ,光合效率午间明显降低 ,主要由非气孔限制引起 .应用逐步多元回归方法 ,得到珊瑚树净光合速率日变化的最优方程为 :Y =- 4 9.8837+0 .0 10 3X1+0 .0 6 75X4+0 .4 913X5(复相关系数R =0 .84 12 ,F值 =4 .84 2 9,显著水平p =0 .0 4 82 ) .偏相关分析和通径分析表明 ,光合有效辐射、空气相对湿度和空气CO2 浓度与净光合速率的日变化有着极显著和显著的相关关系 ,是影响净光合速率的直接主要因子 ,影响的大小顺序为 :光合有效辐射 >空气相对湿度 >胞间CO2

The diurnal variation of photosynthesis of Viburnum odoratissimum leaves under natural conditions is studied. The results are as follows: In summer clear days, the curves of diurnal variation of net photosynthetic rate (P_n) in sunnyleaf have two peaks, which has an obvious decline of photosynthetic efficiency at noon. The mid-depress of P_n is principally caused by non-stomatal limitation. The most excellent equation of the diurnal variation of P_n is attained by the method of stepwise multiple-regression as follows: Y=-49.883 7+0.010 3X_1+0.067 5X_4+0.491 3X_5(R=0.841 2,F=4.842 9,p=0.048 2). The analysis of partial correlation and path on P_n and factors shows that the diurnal variation of P_n has significant correlation with photosynthetic effective radiation (Q_(leaf)) and air relative humidity (RH), respectively. Q_(leaf), RH and c_(air) are the primary factors which affeceted P_n. The order of effect ability on P_n is Q_(laef)>RH>c_(air).