【摘要】 采用营养液培养法,以耐盐性较强的‘秀雅’和耐盐性较弱的‘秀丽’西瓜品种为材料,研究了不同浓度NaCl胁迫对两品种西瓜幼苗活性氧代谢和渗调物质含量的影响。结果显示:NaCl胁迫抑制了西瓜幼苗的生长,耐盐性较强的‘秀雅’受抑制程度明显小于耐盐性较弱的‘秀丽’;随NaCl浓度提高,叶片O2.-产生速率、MDA含量和质膜相对透性显著增加,‘秀丽’的增加幅度明显大于‘秀雅’;POD活性在低浓度NaCl下降低而高浓度下升高,CAT和APX活性及抗坏血酸含量随NaCl浓度提高而显著增加,SOD活性随NaCl浓度变化的规律两品种有所不同;脯氨酸、可溶性糖含量随NaCl浓度提高而显著增加,可溶性蛋白含量在较低浓度NaCl下增加而高浓度下降低;除可溶性蛋白外,50 mmol.L-1以上NaCl胁迫下‘秀雅’抗氧化酶活性、抗坏血酸和渗调物质含量均明显高于‘秀丽’。研究表明:NaCl胁迫严重抑制了西瓜幼苗的生长,破坏了幼苗细胞膜结构,影响了活性氧和渗调物质的正常代谢,耐盐性较强的‘秀雅’受抑制程度和脂质过氧化程度较低,与其抗氧化酶活性和渗调物质含量较高密切相关。更多还原

【Abstract】 The experiment was carried out to study the effect of NaCl stress on the reactive oxygen species metabolism and osmoticum content of watermelon(Citrullus lanatus) seedlings in hydroponically.The results showed that NaCl stress inhibited obviously the growth of watermelon seedling,and the extent of inhibition for ’Xiuya’ was less than that for ’Xiuli’;With increasing NaCl concentration,O-·2 production rate,MDA content and membrane permeability in leaves of both cultivars significantly increased,and increased range of ’Xiuli’ obviously exceeded ’Xiuya’.POD activity declined under the low concentration of NaCl and increased under the high concentration of NaCl.CAT and APX activities,and ascorbic acid content apparently increased with increasing NaCl concentration.SOD activity showed different regularity for two cultivars.Proline and soluble sugar contents significantly increased with increasing NaCl concentration.Soluble protein content increased under the low concentration of NaCl and decreased under the high concentration of NaCl.Besides soluble protein content,the activities of antioxidant enzymes,contents of ascorbic acid and osmotic substances in the leaves of ’Xiuya’ were obviously higher than that in ’Xiuli’ beyond 50 mmol·L-1 NaCl.The research revealed that salinity seriously inhibited the growth of watermelon seedlings,destroyed the structure of cell membrane,influenced normal metabolism of reactive oxygen species and osmoticum.The extent of growth inhibition and lipid peroxidation of ’Xiuya’ seedling were lower than that of ’Xiuli’,which was related with high activities of antioxidant enzymes and high content of osmotic substances.更多还原