黄连木光合特性和水势变化规律的研究

目的]了解林间环境条件下黄连木的光合特性和水势变化规律。方法]选择代表性黄连木作为固定样株,测定其光合速率、蒸腾速率、气孔导度和水势。结果]在上午8:00黄连木净光合速率为全天最高值或较高值,8:00~10:00是净光合速率较高的时间段。净光合速率日变化曲线受环境因子影响分别呈现出双峰或衰减型单峰曲线。黄连木蒸腾速率和气孔导度日变化呈现双峰曲线,净光合速率、蒸腾速率和气孔导度之间存在0.01水平显著的相关性。黄连木枝条水势在上午8:00为全天最低值,而后整个上午都呈上升趋势,至12:00达到最高值。结论]黄连木光合特性和水势变化规律反映出其对外界环境因子不敏感,是一个适应性较强的树种。

Study en Photosynthetic Character and Water Potential Change Law in Pistacia chinesis

Objective] The study aimed to know the photosynthetic character and water potential change law of P.chinesis in forest.Method] The representative P.chinesis was selected as the fixed samples,their photosynthetic rate,transpiration rate,stomatal conductance and water potential were determined.Result] During the whole day,the net photosynthetic rate of P.chinesis was the highest or the higher values at 8 a.m.The time between 8 and 10 a.m.was the time segment when the net photosynthetic rate of P.chinesis was higher.Diurnal variation curve of the net photosynthetic rate appeared to be a double-peaked curve or decreasing single-peaked curve due to influences of environmental factors.Diurnal variation curve of the transpiration rate and stomatal conductance of P.chinesis appeared to be a double-peaked curve.There was an extremely significant correlation among net photosynthesis rate,transpiration rate and stomatal conductance.Water potential of P.chinesis branch reached its lowest value at 8 a.m in the whole day,and then appeared uptrend in the whole a.m,reached its morning peak at 12 a.m.Conclusion] Photosynthetic character and water potential change law of P.chinesis showed that it was not sensitive to external environmental factors.P.chinesis was a tree with strong adaptability.