不同品种露地越冬甘蓝的抗冻性与渗透调节物质含量和抗氧化酶活性

在1月份最低温度条件下(-14．5℃)测定了8398、8132、京丰1号和冬冠1号4个抗冻性不同的甘蓝品种的外叶、球叶和心叶的有关生理生化指标,以评价不同品种不同叶位的抗冻性差异。结果表明,低温冻害严重伤害了甘蓝叶片的膜系统．膜系统的伤害与膜脂过氧化有一定关系。不同品种的伤害程度以冬冠1号最小,京丰1号次之,8398和8132最严重。不同叶位比较以外叶伤害最严重,其次是心叶,球叶伤害最轻,说明冬冠1号的抗冻性较强。测定了不同品种、不同叶位的SOD和POD两种抗氧化酶的活性,不同品种之间SOD活性以冬冠1号较高。POD活性不同叶位之间规律较明显,外叶最低,心叶最高。品种间可溶性糖、可溶性蛋白和游离脯氨酸的含量均以冬冠1号最高,不同叶位之间比较以心叶和外叶较高．球叶较低。分析认为,低温条件下渗透调节物质含量高可能是冬冠1号抗冻性的原因之一；品种之间SOD和POD含量与抗冻性之间有一定关系。不同叶位叶片由于年龄和生理状况不同可能存在着不同的抗冻机制。

STUDIES ON ANTIOXIDATIVE ENZYMES ACTIVITY AND OSMOTYE CONTENT INDIFFERENT CABBAGE CULTIVARS UNDER LOW TEMPERATURE STRESS

To order appraise the low temperature resistance,four different cabbage cultivars were used to study the physiological characteristics of the out leaves,globate leaves and center leaves under low tem- perature.It is indicated that the cabbage leaf membrane was damaged by low temperature stress,and which is related to membrane lipid peroxidation.The smallest damage is occurred in DongGuan NO.1, which is a low temperature resistance cultivar,the second is JingFeng NO.1.The cultivar 8398 and 8132 were damaged seriously,they are low temperature sensitive cultivars.For the leaves in different position, the most serious damage was occurred in the out leaves,then center leaves;and the globate leaves were the smallest.The highest SOD activity was in DongGuan NO.1 of the four cultivars,and the center leav- es took on the highest POD activity of the different position leaves.Three kinds of osmotye dissoluble sugar,dissoluble protein and proline content were detected,and the most content of all occurred in Dong- Guan NO.1 These results suggested that one of the important mechanisms in low temperature resistance for DongGuan NO.1 was accumulating osmotye under low temperature stress.There is some relationship between antioxidative activity and low temperature endurance.The leaves in different position of the cab- bage plant did not employed same mechanisms to tolerate low temperature stress,and which was related to their age and physiological state perhaps.