棉花两品种耐盐性与抗氧化能力的相关性

对‘新陆早17’和‘中棉49’两个棉花（Gossypium hirsutumL.）品种在氧化剂甲基紫精（MV）和NaCl胁迫下的生理应答进行了研究,以期阐明棉花抗氧化能力与耐盐性的关系。研究结果表明,在40μmol·L-1MV胁迫3d,‘新陆早17’的丙二醛（MDA）和活性氧含量比‘中棉49’低,而抗坏血酸（AsA）、超氧化物岐化酶（SOD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性则高于‘中棉49’,表明‘新陆早17’抗氧化能力更强。在200mmol·L-1NaCl胁迫25d,‘新陆早17’的株高和叶绿素降低量、根部Na＋含量、相对电导率都低于‘中棉49’,说明‘新陆早17’耐盐更强。盐胁迫下‘新陆早17’的抗氧化酶活性上升而‘中棉49’却降低,表明‘新陆早17’通过上调SOD、CAT和APX活性来提高其耐盐性。结合棉花两品种的抗氧化和耐盐性差异,说明棉花抗氧化能力的高低能够影响品种的耐盐性。

The Relationship between Salt Tolerance and Antioxidation of Two Cotton Cultivars

The physiological responses to methyl viologen （MV） and NaCl treatment of two cotton （Gossypium hirsutum L.） cultivars （＇XLZ17＇ and ＇ZM49＇） were studied to clarify the relationship between salt tolerance and antioxidant capacity. Under 40 μmol·L-1 MV treatment for 3 d,the content of malondialdehyde （MDA） and reactive oxygen level of ＇XLZ17＇ were significant lower than those of ＇ZM49＇,while the content of ascorbate acid （AsA） and the activity of antioxidant enzymes increased more significantly,including superoxide dismutase （SOD）,catalase （CAT） and ascorbic acid peroxidase （APX）. These results indicated that the antioxidant capacity of ＇XLZ17＇ was stronger than ＇ZM49＇. After 25-day treatment with 200 mmol·L-1 NaCl,the salt tolerance of ＇XLZ17＇ and ＇ZM49＇ was compared. The decrease in shoot length and chlorophyll content,the sodium content in root and the relative electrolyte leakage of ＇XLZ17＇ were lower than those of ＇ZM49＇. These results suggested that ＇XLZ17＇ was more tolerant to salt than ＇ZM49＇ by up-regulating the activity of SOD,CAT and APX under salt stress. Thus,the salt tolerance of cotton could be affected by its antioxidant capacity.