对陕北黄土丘陵区不同立地条件下杜仲(Eucommia ulmoides Oliver)的生长状况和某些生理特性进行了比较研究。结果表明,生长于沟谷、阴坡、阳坡和峁顶的杜仲成活率分别为89.56%、81.26%、73.79%和64.44%,差异显著(P<0.05)。随生长时间的延长,杜仲新生枝和地径生长总体上呈现平缓增加-急剧增加-平缓增加的"S"型变化曲线,生长在沟谷和阴坡的植株新生枝长度和地径生长量显著高于峁顶和阳坡栽植的植株(P<0.05),其中沟谷中杜仲的平均新生枝长度和平均地径最大。在生长期内,杜仲叶片的相对含水量(RWC)总体呈下降的趋势,而水分饱和亏(WSD)总体呈逐渐提高的趋势;在沟谷和阴坡中杜仲叶片的RWC较高、WSD较低,而在阳坡和峁顶上杜仲叶片的RWC较低、WSD较高。杜仲叶片的SOD和CAT活性随生长时间的延长呈现先降低再逐渐升高的趋势;在沟谷和阴坡的植株叶片SOD和CAT活性均高于生长在阳坡和峁顶的植株且差异显著。结果显示,立地条件对杜仲的生长和生理特性有较大影响,土壤水分是影响其生长的主要因素;在沟谷和阴坡立地条件下生长的杜仲具有旺盛的生长力和较强的适应性,沟谷和阴坡是陕北黄土丘陵区杜仲造林的较佳立地条件。

The growth status and some physiological properties of Eucommia ulmoides Oliverat different site conditions were researched in loess hillyregion of Northern Shaanxi. The results show that the survival rate at ravine, shady slope, sunny slope and hill top is 89.56%, 81.26%, 73.79% and 64.44%, respectively, with a significant difference (P< 0.05).The growth of both of new branch and ground diameter presents a typical `S'  curve with slow-rapid-slow increasing trend with growth period  prolonging. The new branch length and ground diameter at ravine and shady slope are significantly higher than those at sunny slope and hill top(P< 0.05), and the largest at ravine. During growing period, the relative water content (RWC) of leaf displays gradual decreasing trend generally, and the water saturation deficit (WSD) of leaf displays gradual increasing trend generally. RWC of leaf is higher and  WSD of leaf is lower at ravine and shady slope, while RWC is lower and WSD is higher at sunny slope and hill top. SOD and CAT activities of leaf appear first going down and then rising trend with growth  period prolonging. And SOD and  CAT activities of leaf at ravine and shady slope are higher than those at sunny slope and hill top, with a significant difference(P< 0.05). It is concluded that the growth and physiological properties of E. ulmoides are affected by site condition remarkably, and the soil water content is a mainly influencing factor. E. ulmoides planted at ravine and shady slope possesses vigorous growth ability and stronger adaptability,  and ravine and shady slope are better site conditions for afforestation of E. ulmoides in loess hilly region of Northern Shaanxi.