5种常绿阔叶植物在北京越冬的抗寒性研究

Study on Cold Resistance of Five Evergreen Broad-leaf Plants during the Winter in Beijing

秋冬季自然降温过程中,以5种常绿阔叶植物为试验材料,通过测定不同月份中各植物叶片的相对电导率及低温半致死温度(LT_(50)),确定抗寒性评价最佳时期;利用主成分分析、隶属函数法对抗寒性评价最佳时期各植物叶片LT_(50)、可溶性蛋白、可溶性糖、游离脯氨酸含量及过氧化物酶活性进行抗寒指标综合评价,评定植物抗寒能力,以期对常绿阔叶植物的选择推广提供理论依据。结果表明,6个月中,5种常绿阔叶植物叶片相对电导率均呈"S"型上升,遵循Logistic的变化规律;LT_(50)随自然温度的变化呈先降后升的趋势,其中,黄杨的LT_(50)为-33.210 3^-13.302 3℃,抗寒能力最强,其他4种植物LT_(50)为-24.268 3^-6.443 1℃;不同月份中各植物LT_(50)排序不同,选择抗寒能力最强且自然温度最低的2月(1月21日—2月21日)为抗寒性评价最佳时期;综合评定2月温度统计区间内各常绿阔叶植物抗寒性依次为:黄杨>冬青卫矛>广玉兰>石楠>皱叶荚蒾。研究表明,LT_(50)可以比较准确地反映植物抗寒性,与抗寒性综合指数排序基本一致。

During the natural decreasing process of air temperature from autumn to winter,the relative electrical conductivity（ REC） and the semi-lethal temperature（ LT50） were determined in leaves of five evergreen broad-leaf plants in order to determine the best period for evaluation of cold resistance. Using principal component analysis and subordinate functions to assess comprehensively the LT50,soluble protein,soluble sugar,peroxide enzyme（ POD） and proline content in the leaves of five tree species in the best period and to provide theoretical basis for the selection and promotion of evergreen broad leaved plants. The results showed that： The REC of the five evergreen broad-leaf plants increased following an S-curve in the 6 months and obeyed the regulation of Logistic model. The LT50 of five tree species decreased with the decrease in temperature firstly,and then increased,the range of LT50 in Buxus sinica（ Rehd. et Wils.） was from -33. 210 3 ℃ to -13. 302 3 ℃,which possessed high cold resistance. The range of LT50 in other four tree species was from -24. 268 3 ℃ to -6. 443 1 ℃,which lower than that of Buxus sinica（ Rehd. et Wils.）. The LT50 sorted differently in different months. The best period of cold resistance evaluation was selected in February（ January 21 th—February 21 th） with the strongest cold resistance and the lowest natural temperature. For a comprehensive evaluation of the cold resistance of the five tree species in February,the results indicated that Buxus sinica（ Rehd. et Wils.） was the strongest cold resistant plant,followed by Euonymus japonicus Thunb.,then Magnolia grandiflora Linn,and Photiniaserrulata Lindl.,finally Viburnum rhytidophyllum Hemsl. The present study showed that LT50 can accurately reflect cold resistance of plants,and it was basically consistent with cold resistant index sorting.