利用模拟降雨控制试验(对照、降雨增加 45%和减少 50%)，研究了黄土高原水蚀风
蚀交错带典型灌木沙柳和柠条茎水力学特性对模拟降雨改变的响应，以揭示两种灌木对未来
降雨改变的适应性．结果表明: 沙柳茎比导水率(K s )、比叶导水率(K l )和 Huber 值对增水有显
著响应，而对干旱无显著响应;柠条黎明前和正午叶水势、水分传输效率(K s 及 K l )对干旱有显
著响应，但对增水无响应．两种灌木不同处理间抵抗栓塞能力无显著差异，沙柳不同处理间正
午原位栓塞程度亦无显著差异，而柠条干旱处理正午原位栓塞程度显著增大．沙柳增水处理
导管直径和导管面积占边材面积的比例显著增加，干旱导致沙柳导管密度显著增大，水力直
径变小;柠条增水处理的木质部结构无明显改变，干旱导致其导管密度和木材密度显著增加．
说明增水提升了沙柳的水力功能，而长期干旱显著降低了柠条水力功能，预测在未来气候旱
化条件下，柠条的水力适应性可能不如沙柳．
其他摘要
With a precipitation manipulation experiment ( Control，+ 45% and － 50%)，the
responses of stem hydraulic traits in two dominant shrubs ( Salix psammophila and Caragana
korshinskii) of water-wind erosion crisscross region of the Loess Plateau to projected precipitation
variation were examined to elucidate their adaptability to future precipitation changes． Ｒesults
showed that the specific hydraulic conductivity (K s )，leaf specific conductivity (K l ) and Huber
value in S． psammophila increased significantly by irrigation but showed no responses to drought．
The predawn and midday leaf water potential and water transport efficiency (K s and K l ) in C．
korshinskii decreased significantly by drought，and showed no responses to irrigation． The embolism
resistance across different treatments did not differ in the two shrubs． The midday native embolisms
across treatments in S． psammophila were almost the same． Drought increased midday native
embolism in C． korshinskii． Irrigation increased conduit diameter and conduit area per stem sap area
while drought increased the vessel density and decreased the hydraulic diameter in S． psammophila．
Irrigation had no effect on xylem anatomy，whereas drought increased the vessel density and wood
density in C． korshinskii． These results indicated that irrigation promoted stem hydraulic function in
S． psammophila，and drought decreased stem hydraulic function in C． korshinskii． C． korshinskii may
be less resistant to future dry climate than S． psammophila．
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