不同土壤水分状况对杨树、沙棘水分关系及生长的影响

在盆栽条件下对杨树、沙棘进行了3种土壤水分处理，研究结果表明：沙棘的叶含水率在同一土壤水分下比杨树高、而水势低，说明沙棘叶的抗旱保水能力强于杨树；沙棘单叶的光合速率能够长时间维持在较高的水平，蒸腾速率却并非如此。杨树无论在生长初期，还是生长中期其单叶WUE均高于沙棘。以新生枝生物量／耗水总量计算的整体WUE在3种土壤水分条件下，杨树的WUE分别是沙棘的2．4倍、2．3倍、2倍，其差异达极显著水平，但在3种土壤水分条件下2个树种都以中度亏缺下的水分利用率最高。整个生长季节处在严重干旱下的杨树和沙棘的生长均受到显著影响，沙棘生长受干旱影响程度小于杨树，从整个生长趋势上看杨树适宜于良好水分下的生长，沙棘在适宜水分和中度亏缺下均可良好生长。

Water relation and growth of seabuckthorn and poplar under different soil water content

It was studied that two species of tree grew under 3 treatments of soil water content,results showed that leaf water content of seabuckthorn is higher and water potential is lower than that of poplar in same soil water content.That results show seabuckthorn has tolerance drought higher than that of poplar.Photosynthesis rate of single leaf seabuckthorn can carry out higher rate in soil drought.Transpiration rate is different of photosynthesis rate.Single leaf water use efficiency of poplar is higher than that of seabuckthorn in growth early days and medium term (May and July).Poplar WUE respectively was 2.4 times,2.3 times,2 times than that of seabuckthorn in total WUE of new branch biomass/total of consumed water and difference was significant level,two species of tree WUE was the best in medium water stress under 3 soil water content given conditions.The growth of seabuckthorn and poplar was obvious retained in total growing season,seabuckthorn effect of growth was smaller than that of poplar.Poplar growing was fitted better water conditions and seabuckthorn growing was better in fitted water and medium water stress from total growing.The result was provided basis of chosen trees species in loess plateau.