中文摘要：

以6份乌塌菜（Brassica campestris L．ssp．chinensis var．rosularis）品种为试验材料，通过低温（5℃，0℃，-5℃，-10℃）胁迫，测定幼苗叶片相对电导率、半致死温度、丙二醛含量、可溶性糖含量、游离脯氨酸含量、叶绿素含量和SOD活性，将各性状在低温与常温下测定值的比值作为耐寒性评价指标，采用相关性分析和聚类分析研究其耐寒性。结果表明，6份乌塌菜品种的半致死温度（LT50）变化范围为．0．30～2．17℃。对各生理生化指标进行相关性分析，相关性不强，评价品种耐寒性需要用多指标测定。对各指标聚类分析表明，相对电导率和丙二醛含量结合起来用于鉴定乌塌菜的耐寒性更准确。通过对乌塌菜品种聚类分析，6份乌塌菜品种中，耐寒性最强的品种是塌地乌6号和徽乌1号；耐寒性较强的品种是徽乌2号、塌地乌2号和塌地乌1号；耐寒性弱的品种为塌地乌3号。

英文摘要：

Under the cold stress （5 ℃, 0℃, -5 ℃ and -10℃） of 6 savoy （Brassica campestris L. ssp. chinensis var. rosularis） varieties, the level of relative electric conductivity, semilet-hal temperature, MDA content, soluble sugar content, free proline content, chlorophyll content and the activiti-es of SOD in leaves of savoy seedlings were evaluated by correlation analysis and cluster analysis. The relative values of the traits at low temperature to those at normal temperature were used to assess cold tolerance. The results showed that the semilethal temperature （LT50） was from -0.30 to -2.17℃. The correlation analysis showed that the six physiological indexes were relatively inde- pendent, so the cold resistance of savoy cultivars should be measured and evaluated by multiple indexes. By cluster analysis of indexes, relative electric conductivity and relative MDA content were suitable for evaluating cold toler- ance. The cold resistance of 6 savoy varieties was evaluated by cluster analysis, Tadiwu 6 and Huiwu 1 had high cold resistance; Huiwu 2,Tadiwu 2 and Tadiwu 1 had medium cold resistance; Tadiwu 3 had poor cold resistance.