以宁夏河东沙地沙生灌木柠条（Caragana korshinskii Kom.）为材料，采用采用盆栽方法分析不同土壤水分条件下的柠条植株叶片蒸腾日变化特征及其与环境因子的相关关系，研究干旱胁迫下柠条蒸腾对主要环境驱动因子的响应机制，为区域植被恢复与重建及林分结构的优化配置提供理论依据。结果表明，（1）充分供水条件下的柠条蒸腾速率是土壤水分严重胁迫下的3.43倍，随着水分胁迫的加剧，蒸腾速率峰值前移，且日蒸腾过程在较为干旱时表现为双峰型；各水分梯度下柠条蒸腾速率日过程与气孔导度具有相同的变化规律，呈极显著的线性相关。（2）随着土壤含水量的逐渐降低，柠条苗木叶片蒸腾速率先增加后缓慢下降，过高的土壤含水量同样会抑制植物的蒸腾，该临界值为15.78%，即土壤质量含水量为田间持水量的74.1%。（3）低光强柠条叶片蒸腾作用的光响应曲线差别不大，都表现出随着光合有效辐射强度增加而缓慢上升的趋势，但启动速度随着土壤含水量的减少而降低；在土壤水分受到限制时（土壤质量含水量≤40%田间持水量），进一步增强光合有效辐射量（≥1000μmol·m-2·s-1）并没有使蒸腾速率提高，严重水分胁迫下，增加光辐射强度反而导致蒸腾速率降低。（4）柠条蒸腾速率的主要影响因子偏相关分析表明：充分供水下，光合有效辐射（PAR）是主要影响因子，贡献率为54.4%；随着土壤含水量的下降，气孔对PAR的敏感性下降，叶片内外水汽压饱和亏缺成为调节柠条蒸腾过程的主导因素。%Caragana korshinskii Kom., a type of psammophilic shrub growing in Hedong sandy land of Ningxia was transplanted in pots in a greenhouse and treated with progressive water stress. The leaf transpiration characteristics under different soil water condition were studied to reveal the response mechanism of plant leaf transpiration to main environmental factors. It is expected that the study will provide the scientific basis for optimizing forest structure allocation of regional vegetation restoration and reconstruction in arid region. It was shown that: (1) The transpiration rate of C. korshinskii Kom. under the adequate soil water supply is exactly 3.43 times than that in severe water stress. The transpiration peak moved forward while increasing of soil water stress, and the daily transpiration rate varied in a double-peak curve under the severe drought stress. There was a linear correlation between leaf transpiration (Tr) and stomatal conductance, both were the same dynamics under different soil water condition. (2) As the soil water content reduction, the transpiration rate of C. korshinskii Kom., after reaching its peak figure, will slowly decrease. The critical value of soil water content (SWC) was 15.78%(that was 74.1%of field moisture capacity). (3) Light response curves of leaf transpiration under low photosynthetically available radiation (PAR) in different SWC made little different. The leaf transpirations under low solar radiation were up with linear while increasing of PAR. However, the start-up speeds of Tr were decrease with soil water content reduction. Under the soil water stress (SWC≤40% of field moisture capacity), any further increase in PAR (≥1 000μmol·m-2·s-1), however, was not helpful to improve Tr. Meanwhile, it was arguable that increase the light radiation intensity led to decreased transpiration rate under the severe soil water stress. And (4) after analysis of partial correlations, the PAR was the major factor influencing changes of Tr under the adequate soil water supply, contributing 54.4%of the variation Tr. But with the decline in soil moisture, the sensitivity of stomata decreased to PAR. The vapour pressure deficit between air and leaf became the dominant factor in regulating transpiration process of C. korshinskii Kom..
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