【摘要】 采用人工光氧化技术对30个常见白菜栽培品种进行光氧化处理,以总叶绿素存留率作为评价指标,利用系统聚类分析将供试品种划分为5个级别(1~5级)。其中耐光氧化能力强的品种有青优4号、暑绿、抗热605、绿扬青、矮抗6号、华王;不耐光氧化的品种有四倍体矮脚黄、绿星。在此基础上,以耐光氧化品种抗热605与不耐光氧化品种绿星为材料,研究了光氧化过程中活性氧代谢的特征。结果表明:在光氧化条件下,白菜叶片内的抗氧化酶SOD、POD、CAT、APX活性受光氧化诱导升高,但光氧化敏感性品种绿星的酶活性很快下降,耐光氧化品种抗热605的酶活持续保持在较高的水平。因此,绿星的O2·生成速率、H2O2含量及MDA的积累量均高于抗热605,最终导致品种绿星在光氧化下总叶绿素存留率低。表明抗热605植株内较高的抗氧化酶活性对提高耐光氧化能力起了重要作用。更多还原

【Abstract】 Thirty cultivars of pak-choi（Brassica campestris ssp. chinensis Makino）were divided into five grades according to their photooxidation tolerance by the residual content of total chlorophylls under artificial photooxidation condition, where the tolerant ones included Qingyou 4, Shulü, Kangre 605, Lüyang Qing, Aikang 6 and Huawang, and the susceptible ones were Lüxing and Aijiao Huang. In order to study the characteristics of reactive oxygen metabolism between pak-chio varieties with different photooxidation tolerance, Kangre 605 and Lüxing were used to compare the differences in the paper. The results showed that the activities of antioxidant enzymes including superoxide dismutase （SOD）, peroxidase （POD）, catalase （CAT）and ascorbate peroxidase （APX） in the two cultivars were induced at the beginning of photooxidation stress, and then decreased in the sensitive Lüxing, but that of the tolerant Kangre 605 continued to keep at a higher levels. Additionally, the O^·₂ production rate and the content of H₂O₂ and malondialdehyde （MDA） in Lüxing were higher than that in Kangre 605, which might be the cause leading to a lower level of chlorophylls. These results suggested that higher antioxidant enzyme activities played an important role in Kangre 605 against photooxidation stress.更多还原