紫荆光合日变化及其与环境因子的关系

Study on Diurnal Variation of Photosynthesis for Cercis chinensis Bunge and Its Relation to Environmental Factors

在自然条件下,对紫荆光合作用日进程的研究结果表明,夏季晴天紫荆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紫荆净光合速率日变化的最优方程为:Y=11.0167+0.0051X1-0.0573X2+0.3690X3(复相关系数R=0.8695,F=8.2604,显著水平p=0.0078).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密切关系,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>空气CO2浓度.

The diurnal variation of photosynthesis for Cercis chinensis Bunge leaves had been studied under the natural conditions. The results were as follows: In summer clear days, the curves of diurnal variations of net photosynthetic rate ( P _n) had two peaks, which had an obvious phenomenon of midday decline of photosynthetic efficiency. The mid-depress of P_n was principally caused by non-stomatal limited elements i.e. photoinhibition and photorespiration. The optimal equation of the diurnal variation of P_n was attained by the method of stepwise multi-regression, which was: Y=11.016 7+0.005 1X_1-0.057 3X_2+(0.369 0X_3) ((R=0.869 5,)F=8.260 4,p=0.007 8 ). The analysis of partial correlation and path coefficient on P_n and factors showed that the diurnal variation of P_n had closer relations to photosynthetic active relation ( Q ), air relative humidity ( RH ), and CO_2 concentration (C_a) in the air. Q,RH and C_a were the primary direct factors affecting P_n . Their sequences were Q>RH>C_a .