羽衣甘蓝抗寒生理特性研究

观赏羽衣甘蓝作为秋冬季节重要的园林绿化植物,抗寒性直接影响其推广和应用。为了阐明羽衣甘蓝响应低温的生理特性,揭示抗寒机理,以北京市农林科学院蔬菜研究中心生物技术课题组选配的优良F1杂种作为研究试材,分析不同低温处理下叶片电导率变化和半致死温度,以及渗透调节物质含量和抗氧化酶活性的变化。结果显示,羽衣甘蓝叶片电导率在-5℃以下迅速升高,-10℃左右达到最大值;半致死温度为-10.3~-13.7℃,红色类型低于白色类型,羽叶和圆叶低于皱叶类型。上述研究结果与观赏羽衣甘蓝田间抗寒表现一致。低温处理下渗透调节物质含量和抗氧化酶活性响应特性表明,不同指标呈现不同的变化趋势,除了可溶性糖在-10℃含量最高外,可溶性蛋白和游离脯氨酸含量,以及超氧化物歧化酶(SOD)和过氧化物酶(POD)活性均在-5℃或-8℃达到最大值,并随温度进一步降低而下降。主成分分析结果表明半致死温度、可溶性糖和游离脯氨酸含量是导致羽衣甘蓝抗寒性差异的主要因素。研究结果为建立羽衣甘蓝抗寒性评价体系,进一步解析抗冻机理,培育抗寒新品种奠定理论基础。

The Physiological Characteristics of Ornamental Kale for Cold Resistance

Kales,which are widely cultivated as ornamental plants in wintertime or cold areas,play important roles for urban landscaping.Cold stress which can reduce the ornamental value is one of the most important charac-ters for the improvement and breeding of kales.In order to elucidate the physiological characteristics during low tem-perature and reveal cold resistance mechanism,several varieties and strains which were bred by our group were used as research materials.The relative electrical conductivity (REC)under different low temperature treatment,semi-le-thal temperature (LT50 )of different accessions,as well as the osmoregulation substances contents and antioxidant enzymes activities under different temperature treatment were analyzed.It was showed that the REC of kale leaves increased rapidly when temperature under -5 ℃,and reached maximum values at about -10 ℃.The TL50 values of kale accessions were -10.3 --13.7 ℃.The TL50 s of red types were lower than white types,as well as round and leatherleaf types were lower than wrinkle types.These results were consistent with field cold resistance perform-ances of the varieties.Changing characteristics of the detected osmoregulation substances and antioxidant enzyme ac-tivities were different under different temperature treatments.These physiological indexes reached maximum values at -5 ℃ or -8 ℃ and decreased at lower temperature,except soluble sugar which reached maximum value at-10 ℃.The principal component analysis revealed that LT50 value,soluble sugar and free proline contents were main components causing cold resistance variations among different varieties.These results will provide theoretical basis for the establishment of kale cold resistance evaluation system,and lay foundation for the development of new varieties with excellent cold resistance.