【摘要】 采用Li-6200光合分析仪,在自然条件下对沙冬青(A.mongolicus(Maxim)Chengf.)光合作用日进程进行了观测,结果表明:在夏季晴天条件下,沙冬青Pn日变化为双峰曲线,峰值分别出现在11:00时和15:00时,具有典型的“光合午休”特征。相关分析和多元回归分析表明,光量子密度和气孔阻力是影响沙冬青叶片Pn日变化的主要生态因子。更多还原

【Abstract】 Diurnal variations of photosynthesis of A.mongolicus were studied under natural conditions by Li-6200 photosynthesis analyzer.The results indicated that in the typical summer sunny days,the curve of diurnal variation of net photosynthetic rate（Pn） was dual-peaked.The peak values appeared at 11:00 and 15:00 respectively.The first peak value was 6.031 μmolCO₂·m-2·s-1 and the second one was 5.296 μmolCO₂·m-2·s-1.There was a clear depression at noon,which was 4.798 μmolCO₂·m-2·s-1 appeared at 13:00.The analysis of correlation and stepwise multi-regression showed that the main ecological factors affecting photosynthetic diurnal variation of A.mongolicus were photo flux density and stomatal resistance.更多还原