河北杨水分生理状况的研究

Physiological Status of Water to Populus hopeiensis in Yan′an

本文研究了延安河北杨人工林蒸腾、水势、饱和亏、生长量等的变化规律，寻求其与环境变化的关系。结果表明：河北杨水势和蒸腾强度日变化皆呈单峰曲线，水势早晚高中午低，蒸腾强度相反；叶蒸腾的季节变化呈双峰曲线，与树干生长量变化趋势一致，蒸腾强度与土壤含水量和气温呈正相关，与大气湿度呈负相关，春季其水分亏缺严重，也是需水最多的季节；土壤水分是限制河北杨生长的主要因子。

Tendency of transpiration,water potential saturation deficit, growth and their relationship with environmental conditions in Yan′an were investigated changes of the leaf water potential in a day could be revealed with a single peak curve,the maximum value appeared at noon. The seasonal variation of leaf transpiration appeared a double peak curve similar to that of truck growth negative related to soil moisture and air humidity,positive to temperature, the spring was the season of serious shortage and strong need of water.The soil moisture was the key factor controlling the growth of Populus hopeiensis . Afferestation of Populus hopeiensis should select better sites and adopt run-off foresty in the area.