[目的]研究金叶榆(由河北林业科学院从家榆实生苗中新选育出的品种)的抗寒性,为其在北方地区种植适应范围提供科学依据.[方法]金叶榆和家榆的枝条经梯度冷冻处理,用其枝条的相对电导率、K+相对外渗率直接推测其半致死温度的范围,再结合Logis-tic方程建立回归方程,确定其半致死温度点(LT50).[结果]金叶榆和家榆枝条相对电导率和K+相对外渗率均大体呈S型曲线变化;家榆半致死温度范围为-33.1～33.7℃,金叶榆半致死温度范围为-30.3～31.2℃,与枝条生长恢复观测结果相符.[结论]金叶榆的抗寒能力比家榆略低,推广应用时,应给予适当注意.%[ Objective ] The scientific basis of the planting region of the Ulmus pumila ' Jinye' , which was bred by Hebei Academy of Forestry Science, in northern China was provided through the research on its resistance. [ Method ] The range of semi - lethal temperature of the Ulmus pumila ' Jinye' could directly estimated through the analysis of the relative conductivity and the relative electrolyte leakage rate of K + of the Ulmus pumila ' Jinye' and Ulmus pumila branches that were treated with gradient low temperature. And the semi - lethal temperature (LT50 ) could be assured through the calculation of those indexes with the formation of the regression equation based on the logistic equation. [ Results] There was a type of variation of S - curve in the relative conductivity and the relative electrolyte leakage rate of K + of the Ulmus pumila 'Jinye' and Ulmus pumila branches. The LT50 of Ulmus pumila was from -33.1 to -33.7 ℃ and Ulmus pumila 'Jinye' , from 30.3 to 31. 2 ℃, which was same as the observation result of the recovery growth of branches. [ Conclusion] The resistance of Ulmus pumila ' Jinye' to cold was lower than that of Ulmus pumila and attention to the protection the Ulmus pumila ' Jinye' bee from cold damage was paid during its extension.
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