【摘要】 本文测试了风沙土上着生梭梭的ＳＰＡＣ系统的水分关系和Ｐ－Ｖ曲线的水分特征，分析结果表明：沙上含水率（ω）大于２．０％，梭梭生长正常，蒸腾速率（Ｔｒ）主要受光照强度（Ｌｉ）的影响，关系为Ｔｒ＝ａ＋ｂＬｉ而ω小于２．０％，同化枝水势（ψ＿Ｐ）成为影响Ｔｒ的主要因子之一，此时有：Ｔｒ＝ａ＋ｂＬｉ＋ＣψＰ；ω与同化枝清晨水势（ψ＿ｍ）的关系为、ψ＿ｍ＝－４．６３９６×０．７７３６４９ｗ；转点ω＝２．０％，ψ＿ｍ＝－２．９ＭＰａ大于说明梭梭仍能恢复膨压；ω与ψｓ的关系为：ψ＿ｓ＝１０．９１９４５×０．２５５５９ｗ，转，乏又是ω＝２．０％；ω小于２．０％，ψ＿ｓ迅速下降，ω＝２．０％为“临界阈’，多ω＝１．０％时，ψ＿ｍ＝－３．５ＭＰａ小于说明梭梭已不能恢复膨压高的束缚水，低的和是梭梭耐旱的主要生理特征，进而形成一套抗旱的生理生态水分关系。更多还原

【Abstract】 The paper have investigated the physio-ecological water relation-ehip of the SPAC system and water parameters of P-V curve on Saxaui grow-ing in aeolian sandy soil. The results are as follows. When the waterContent (ω)of the aeolian sandv soil is above 2%, the plant grows verywell, the transperation rate(Tr) is mainlv controlled by the light intensity(Li),and the relationship between Tr and Li is Tr= a+b× Li(a and b are coe-fficients).When the water content is below 2%, the water potential(ψ_p) of photosynthetic branch is one of the main factors that affect Tr, and the rela-tionship among the three factors is Tr=a+b× Li+c×ψ_p,(a,b and c are offi-cients).The relationship between ω and the water potential(ψ_m)of photosy-nthetic branch measured in early morning is:ψ_m=-4.6396 × 773649w,ω= 2% isturning point while ψ_m conyerts the slowly fall into the fast one,and thefact that ψ_m=-2.88MPa is above shows the plant maymainturgor potential.The relationship between ω and the water potential in theaeolian sandy soil(ψ_s)is ψ_s=-10.9194×0.25559,ω=0.2% is just the pointthat convert the slowly fall into the fast one and corresponding ψ_s=-0.7MPa,ω= 2%is the″critical value″that saxaul can grow very well. Whenω is about 1%,=-3.5MPa is blow which shows the saxsul can’t tmain-tain turgor potential. The high Va with no high is one of the main physiolo-gical characters in drought-resistance for saxaul,which forrn a system ofphysio-ecological water relationship in brouerboht-resiStance.更多还原