田间珊瑚树净光合速率及生态因子的日变化

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 浓度

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

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).