干旱胁迫对华南地区三种苗木蒸腾耗水的影响

石灰岩裸露地区土壤普遍具有土层浅薄、保水性差的特征，因此石灰岩地区植物会经常面临干旱胁迫逆境。该研究选择华南石灰岩地区常见的任豆，以及两种石灰岩地区造林供选树种楝叶吴茱萸、车轮梅，通过比较分析这三种植物的盆栽苗木在不同的干旱胁迫程度下的叶片水势、耗水量以及耗水速率，揭示蒸腾耗水规律，为评价植物抗旱性能提供参考依据，同时为在水分亏缺条件下进行造林或者植被恢复提供理论指导。实验结果表明，三种苗木以白天的耗水为主；在不同水分条件下，日总耗水量的大小顺序均为：任豆〉车轮梅〉楝叶吴莱萸正常水分条件下三种苗木的耗水速率日变化趋势呈“单峰”曲线，轻度干旱胁迫时，楝叶吴菜萸和车轮梅的耗水速率日变化趋势则呈“双峰”曲线，其中值得注意的是在干旱胁迫较为严重时，三种苗木的耗水速率受环境温、湿度的影响比较小，在7．9～114．3μmol．m^-1·s^-1之间。综合实际耗水速率的降幅以及重度干旱胁迫下的耗水速率来看，抗旱节水性能大小为：任豆〉车轮梅〉楝叶吴茱萸。

Influence of Drought Stress on Water consumption through Transpiration =of Seedlings of 3 Tree Species in South China

In limestone areas,soil generally is shallow and has poor water conservation capability,so plants often encounter drought stress.Evodia meliaefolia is a common species in limestone areas of South China.Rhaphiolepis indica and Zenia insignis are two kinds of species for afforestation in limestone area.The water consumption of these three species under drought stress were investigated to evaluate the drought resistance ability,for improving the theoretical foundation of forestation and vegetation restoration under drought stress.Leaf water potential and water consumption rate of potted seedlings of these three species in different drought stress conditions were measured.The results showed that water consumption of the three species mainly occurred in the daytime.In all water condition,the order of daily water consumption amount are Z.insignis > R.indica > E.meliaefolia.For these three plants without drought stress,the daily variatioin of water consumption rate followed the curve with one peak,while it changes to double peak under low drought stress for E.meliaefolia and R.indica.When the drought stress is serious,the water consumption rates of these three plants were 7.9~114.3 μmol·m-2·s-1,and slightly affected by temperature and humidity.Considering the change of water consumption rate,the order of drought resisting ability of the three species is Z.insignis > R.indica > E.meliaefolia.