大青山南麓阳坡油松生长的适宜土壤水分环境研究

在大青山南麓浅山地带的阳坡造林地，使用Li-6400便携式光合测定仪对不同土壤水分处理下的油松（Pinus tabulaeformis）苗木的光合生理参数进行了测定。为了确定适宜油松生长的土壤水分范围，研究了叶片净光合速率（Pn）、羧化效率（Ce）、蒸腾速率（Tr）、水分利用效率（WUE）对土壤含水量（SWC）的响应过程，并探讨了在不同土壤水分状况下叶片光合作用的变化规律。研究表明:维持油松最佳Pn的SWC为17.9%；维持最佳WUE的SWC为14.66%；维持最佳Ce的SWC为16.43%；油松的土壤水合补偿点为3.74%，Tr最大时的SWC为18.7%。根据大青山南麓阳坡造林地的立地条件，选取维持最佳WUE的SWC临界值和维持最佳Pn 70%相应的SWC作为油松生长的适宜土壤水分环境上下限，这一指标可量化为10.85%～14.66%。

Study on Suitable Soil Moisture Condition for Pinus tabulaeformis on the Sunny Slope in Southern Foothill of Daqing Mountains

A Li-6400 portable photosynthesis system was used to measure a few of photosynthetic physiology parameters of Pinus tabulaeformis growing under different soil water contents (SWC) on the sunny slope in southern foothill of Daqing Mountains. In order to determine the range of suitable SWC of the tree species growth, the response processes of net photosynthesis rate (Pn), carboxylation efficiency (Ce), transpiration rate (Tr), water use efficiency (WUE) to different SWC were studied, and the rule of its photosynthesis under different SWC was explored. The results show that the soil water contents keeping optimum Pn and WUE, as well as Ce of Pinus tabulaeformis are 17.9% and 14.66%, as well as 16.43%, respectively; that soil water compensation point for hydration of the tree species is 3.74%, and the SWC causing the maximum Tr of that is 18.7%. In the light of site condition of the sunny slope, the SWC maintaining the best WUE of leaf and the SWC corresponding with the Pn which is equivalent to 70% of the best Pn can be chosen as the upper limit and the lower limit for the rang of suitable SWC. The general index can be quantified as 10.85%～14.66%.