毛乌素优势植物杨柴( Hedysarum mongolicum Turcz .) 对高 CO2浓度和土壤干旱胁迫响应的研究结果表明:干旱胁迫可使杨柴根系伸长, 根生物量、地径、主茎高和茎生物量下降;高 CO2浓度使杨柴根和茎生物量明显增加, CO2的“ 施肥效应” 显著, 干旱使 CO2的“ 施肥效应” 减弱。 同时, 土壤干旱胁迫使杨柴的根/冠比增加, 说明在土壤干旱胁迫情况下根的生长比地上部分( 茎) 的生长更活跃, 有利于提高杨柴在干旱沙漠地区的固沙作用;CO2浓度升高和土壤干旱胁迫均使杨柴叶片的水势下降, 叶片水势的下降使叶片细胞对水分的束缚力增强, 从而减少植物蒸腾耗水, 有利于提高水资源的利用效率。
 

Thr response of Hedysarum mongolicum Turcz ., a dominant plant species in Maowusu sandland, to high CO2 concentration and soil drought stress was studied .The results showed that the soil drought stress lengthened root length, decreased the dry biomass of root and stalk and the growth value of basal diameter and stalk height .The high CO2 concentration increased the dry biomass of root and stalk .The “fertilizer effect” of CO2 was significant .But soil drought weakened the “fertilizer effect” of CO2 .Meanwhile, the soil drought stress increased root/canopy ratio, it meant that the root growth is more activity than that of stalk growth in the soil drought stress case, and advantages to the fixing-sand effect of H .mongolicum in drought desert regions .CO2 concentration increment and soil drought stress was decreased leaf water potential of H .mongolicum, it enhanced the tie power of leaf cell to water .So, it can decrease plant transpiration and advance water use efficiency .