不同程度的水分胁迫对中间锦鸡儿幼苗气体交换特征的影响

为探讨未来降水减少对内蒙古皇甫川流域人工栽培主要灌木树种中间锦鸡儿气体交换特征的影响 ,特设计正常降雨水平、偏旱、干旱和极端干旱 4种水分处理水平 ,进行人工模拟水分胁迫实验。结果表明 ,不同的水分处理显著影响土壤含水量、土壤温度、净光合速率、气孔导度、蒸腾速率、资源利用效率和叶片水势。适度的水分胁迫 (干旱环境 )能够提高中间锦鸡儿的水分利用效率和抗旱性 ,同时也降低了净光合速率与蒸腾速率。随水分胁迫的增强 ,中间锦鸡儿的净光合速率日变化曲线逐渐从典型的单峰型转变成双峰型 ,出现光合“午睡”现象。根据 Farquhar和 Sharkey提出的判别标准 ,干旱和极端干旱下光合“午睡”的原因分别以气孔因素和非气孔因素 (叶肉细胞光合能力下降 )为主。中间锦鸡儿通过自身的生理调节以抵抗干旱 ,是其能够适应干旱环境、历经 3a大旱而幸存下来的重要原因

Effects of severity of water stress on gas exchange characteristics of Caragana intermedia seedlings

Water availability is one of the major limits for the plant growth and development, and the way an environmental factor such as water can affect plant growth is to influence plant physiological process and conditions. The physical environment in arid and semi-arid areas may become more and more severe because of global warming and local drying. Experimental evidences for the effects of precipitation change, especially of severity of water stress, on plant individuals are important basis for further understa...