彩叶乔木树种“金叶榆”的抗寒性研究

Research on the Resistance of the Ulmus pumila 'Jinye' to Cold

[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＇ tree from cold damage was paid during its extension.