低温胁迫对不同倍性不结球白菜生长及生理生化特征的影响

Growth,Physiological and Biochemical Characteristics of Non-heading Chinese Cabbage under Low Temperature Stress

在田间自然低温条件下对二、四倍体不结球白菜的生长特性进行了比较研究，并在光照培养箱中于一5～5℃条件下，分析低温胁迫对它们生理生化特征的影响。结果表明：（1）四倍体不结球白菜的10叶厚、叶柄宽和厚、单株重、单株叶重、叶重／叶柄重及小区产量等农艺性状均显著高于其同源二倍体；（2）随温度的降低，二、四倍体不结球白菜的叶片可溶性蛋白质、可溶性糖及游离脯氨酸等渗透调节物质含量明显上升，电解质外渗率增大，丙二醛（MDA）含量升高，保护酶SOD、POD和CAT活性则先升高后降，而且四倍体材料的渗透调节物质含量和保护酶活性在低温胁迫过程中始终明显高于二倍体，但电解质外渗率和丙二醛含量低于二倍体。研究发现，低温胁迫下渗透调节物质含量升高和保持较高的保护酶活性是四倍体不结球白菜抗寒性强的主要原因。

Growth characteristics of diploid and tetraploid non-heading Chinese cabbage seedlings were compared under low temperature in field conditions . The physiological and biochemical characteristics in nonheading Chinese cabbage leaves were researched under low temperature stress （-5 - 5℃） in diurnal growth incubator. The results showed that the differences of diploid and tetraploid agronomic characters on thickness of ten leaves,width of petiole, thickness of petioles,weight per plant,weight of leaves per plant, leaves/petioles weight were significant;the contents of soluble protein,soluble sugar, free proline increased with the temperature decreasing,the leakage rate of electrolyte and MDA content were increased, but the activities of SOD,POD and CAT increased at first and then decreased in the two materials. There were significant differences on the contents of OAM between diploid and tetraploid non-heading Chinese cabbage cultivars. The contents of OAM and protective enzymes of tetraploid were higher than those of diploid, which showed they had strong resistance to low temperature. Higher OAM content and higher activities of SOD,POD,and CAT was the mainly reason that lead to strong resistance to low temperature of tetraploid non-heading Chinese cabbage.