【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:沙土含水串（w）大于2.0％,梭梭生长正常,蒸腾速串（T_r）主要受光照强度（L_i）的影响,关系为T_r=α+bL_i而W小于2.0％,同化枝水势（ψ_p）成为影响T_r的主要因子之一,此时有,T_r=α+bL_i+Cψ_i;w与同化枝清晨水势（ψ_m）的关系力,ψ_m=-4.6396×0.773649_i^w转点W=2.0％,ψ_m=-2.9MPa大于ψ_z^o=-3/4MPa说明梭梭仍能恢复膨压,W与ψ_s的关系为:ψ_z=10.91945×0.25559w,转点又是W=2.0％;W小于2.0％,ψ_s迅速下降,W=2.0％为‘临界闸’,到W=1.0％时,ψ_m=-3.6MPa小于,ψ_x^o,说明梭梭已不能恢复膨压高的束缚水.低的ζ_{m x}和ψ_x^o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 relationship of the SPAC system and water parameters of P-V curve on Saxaul growing in aeolian sandy soil. The results are as follows. When the water Content (to) of the aeolian sandy soil is above 2%, the plant grows very well, the trans-peration rate (Tr) is mainly controlled by the light intensity (Li), and the relationship between Tr and Li is Tr = a+b×Li(a and b are coefficients). When the water content is below 2%,the water potential ((?)p) of photosyn-thetic branch is one of the main factors that affect Tr, and the relationship among the three factors is Tr= α+b×Li + c×(?)p(α, b and c are coefficients). The relationship between w and the water potential((?)m) of photosynthetic branch measured in early morning is:(?)m= -4.6396×0.773649w, w = 2% is turning point while (?)m converts the slowly fall into the fast one, and the fact that (?)m= -2.88MPa is above (?)x0 = -3.4MPa shows the plant may maintain turgor potential. The relationship between w and the water potential in the aeolian sandy soil ((?)s) is:W, = -10.9194×0.25559w, w = 2% is just the point that convert the slowly fall into the fast one and corresponding (?)s = -0.7MPa, w = 2% is the "critical value" that saxaul can grow very well. When to is about 1%, = -3.5MPa is blow (?)x0,which shows thesaxaul can’t maintain turgor potential. The high Va with no high is one of the main physiological characters in drought-resistance for saxaul,which form a system of physio-ecological water relationship in drought-resistance.更多还原