水保所知识产出(1956---)知识库

比较了陕北沙地沙柳、柠条和沙棘3 种典型灌木不同土壤深度( 0～20 和30～ 50 cm)
根木质部解剖结构和水力特性．结果表明: 沙柳具有较高的叶水势，根木质部导管平均最大直
径( dmax
) 、平均最小直径( dmin
) 、平均导管面积( Alum
) 以及导管面积占木质部面积比例( Aves /
Axyl
) 显著高于柠条和沙棘，根导管密度( VD) 与沙棘相当但显著高于柠条; 沙柳根的比导水率
分别为柠条和沙棘的5．0 和2．8 倍; 沙柳根栓塞脆弱性指数与柠条根相当，但显著高于沙棘
根．表明沙柳属耗水型水分利用策略，而柠条和沙棘属节水型水分利用策略，且柠条更耐旱．3
种灌木在2 个土层深度的dmax、dmin
和Alum
无显著差异，但30～50 cm 土层根VD 和Aves /Axyl
显著
高于表层; 30～50 cm 土层根比导水率显著高于表层根，但脆弱性指数小于表层根，深层根具
有高的水分传输效率和低的水力脆弱性．

Ｒoot xylem anatomical structure and hydraulic traits of three typical shrubs，i．e．，Salix
psammophila，Caragana korshinskii and Hippophae rhamnoides，within two soil layers ( 0－20 cm
and 30－50 cm) were compared． The results showed that S． psammophila had a higher leaf water potential
than C． korshinskii and H． rhamnoides，the average maximum and minimum lumen diameter
( dmax and dmin
，respectively) ，the average lumen area of vessels ( Alum
) and the ratio of lumen area
of all vessels to xylem area ( Aves /Axyl
) in S． psammophila roots were also significantly higher than
those in C． korshinskii and H． rhamnoides，and the root vessel density ( VD) in S． psammophila was
the same as that in H． rhamnoides but significantly higher than that in C． korshinskii． Ｒoot hydraulic
conductivity in S． psammophila was 5 times of C． korshinskii and 2．8 times of H． hamnoides． The
vulnerability index in S． psammophila roots was similar to that in C． korshinskii but higher than that
in H． hamnoides． S． psammophila belonged to a water-spending species，whereas both C． korshinskii
and H． rhamnoides were water-saving species，and C． korshinskii was more drought-resistant than H．
rhamnoides． There was no difference of dmax
，dminand Alum between roots in two soil layers，but roots
within in the 30－50 cm soil layer had larger VD and Aves /Axyl ． The root specific hydraulic conductivity
within the 30 － 50 cm soil layer was significantly higher than within the surface soil layer，
whereas the vulnerability index within the 30－50 cm soil layer was smaller，indicating roots in deep
soil layers had higher hydraulic transport efficiency and lower hydraulic vulnerability．