乌兰布和沙区沙棘光合蒸腾日变化与主要环境因子的关系

摘要

Under natural conditions,diurnal changes of photosynthetic and transpiration rate of six sea-buckthorn cultivars and main environmental factors were measured by using LI-6400 photosynthesis sys-tem.The correlation coefficient,path coefficient and decision coefficient were used to determine the effects of main environmental factors on the diurnal changes of photosynthetic and transpiration rate of sea-buck-thorn cultivars.The results were as follows:Diurnal change of photosynthetic rate of six sea-buckthorn cul-tivars showed bimodal pattern and an obvious midday depression at 13∶00 o’clock.Diurnal change of tran-spiration rate of ‘Baiqiu’and ‘Shenqiuhong’both showed bimodal pattern,which of the others showed u-nimodal pattern.PAR had the greatest effect on the diurnal dynamics of photosynthetic and transpiration, and was the primary determining factor.C a ,T a and RH affected photosynthetic and transpiration mainly through their acting on PAR,and were the main limiting factors.%在自然条件下，利用 LI-6400光合仪，测定了乌兰布和沙漠6个沙棘品种的光合蒸腾特性及主要环境因子的日变化，并采用相关系数、通径系数和决策系数探讨了主要环境因子对沙棘品种光合蒸腾日变化的影响。结果表明：6个沙棘品种的净光合速率呈典型的“双峰”曲线，在13∶00左右有明显的光合“午休”现象；‘白丘’与‘深秋红’蒸腾速率日变化呈“双峰”曲线，其余4个沙棘品种呈“单峰”曲线；PAR 是直接影响沙棘光合蒸腾速率日变化的最大环境因子，并起主要决策作用；C a 、T a 和 RH 间接影响沙棘的光合蒸腾速率日变化，是主要限制因子。