杜鹃花品种耐寒性比较及其机制研究

以杜鹃花品种‘埃尔西 ? 李’、‘紫萼’和‘紫蝴蝶’为材料，在浙江杭州自然低温条件下（2013年12月至2014年3月）测定7个取样时期的叶片相对电导率，结合Logistic方程计算半致死温度（LT50），并比较耐寒性强弱。同时测定耐寒性相关生理指标，通过主成分及相关性分析发现，蔗糖、可溶性蛋白、脯氨酸、丙二醛的含量与杜鹃花耐寒性关系密切，较高的蔗糖积累量及可溶性蛋白、脯氨酸含量可能是‘埃尔西 ? 李’抵御寒冷的主要途径；由MDA含量推测，膜脂不饱和脂肪酸含量上升可能是另一途径。运用隶属函数法对3个杜鹃花品种耐寒性进行综合评价，‘埃尔西 ? 李’耐寒性最强，‘紫蝴蝶’和‘紫萼’耐寒性相似，结合园林应用及冬季表现情况，判定‘紫蝴蝶’耐寒性稍好于‘紫萼’。

A Study on Cold Tolerance Difference and Its Mechanisms in Azalea Cultivars

To analyze the cold tolerance differences in azalea cultivars of‘Elsie Lee’，‘Zi’e’and ‘Zihudie’，under natural low temperatures in Hangzhou（during Dec. 2013 to Mar. 2014），the relative leaf electric conductivities at seven sampling periods were determined and LT50 values were calculated using logistic equation. Moreover，some cold tolerance related physiological factors were measured，and through principal components analysis and correlation analysis，it was shown that the content of sucrose，soluble proteins，MDA and proline were closely related to cold tolerance in azalea. The accumulation of high level of sucrose as well as soluble proteins and proline played important roles in the cold tolerance in‘Elsie Lee’. Based on the data on the concent of MDA，it was suggested that the increase in contents of unsaturated fatty acid in lipid membrane may be another explanation for the stronger cold tolerance in ‘Elsie Lee’. Using subordinate function method to comprehensively evaluate the cold tolerance in three cultivars，it was found that‘Elsie Lee’ranked first and followed by‘Zihudie’and‘Zi’e’which had similar cold tolerance according to the data from tolerance evaluation by LT50 and SF method，and it can be concluded that the cold tolerance of‘Zihudie’is slightly stronger than‘Zi’e’based on their growth behaviors during winter seasons.