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为探究NO和ABA对辣椒幼苗自毒作用缓解的生理生化机制,以蛭石珍珠岩混合基质栽培的辣椒‘陇椒2号’幼苗为材料,用连作3年辣椒的土壤和基质浸提液浇灌幼苗,研究喷施外源SNP(NO供体,150μmol·L-1)和ABA(100μmol·L-1)对自毒作用下辣椒幼苗叶片的抗氧化酶活性、抗氧化剂和渗透调节物质含量、膜脂过氧化损伤的影响。结果表明,土壤和基质浸提液均导致辣椒幼苗叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性,以及脱氢抗坏血酸(DHA)含量的下降;还原型抗坏血酸(AsA)、脯氨酸(Pro)、可溶性蛋白和丙二醛(MDA)含量,以及相对电导率和AsA/DHA上升;土壤浸提液胁迫程度显著大于基质浸提液。外源NO和ABA处理显著提高辣椒幼苗叶片的SOD、POD和CAT活性,以及Pro和可溶性蛋白含量,降低MDA含量和相对电导率,显著促进AsA含量升高和DHA含量下降,维持较高的AsA/DHA,NO对自毒作用下辣椒幼苗氧化损伤的缓解效应显著好于ABA。研究结果表明外源NO和ABA通过提高自毒作用下辣椒抗氧化酶活性、渗透调节物质含量和AsA/DHA比值,有效地阻止辣椒体内MDA积累和电解质渗漏,缓解自毒作用对辣椒幼苗造成的膜脂过氧化,增强辣椒的抗逆性。
In order to explore the physiological and biochemical mechanism of NO and ABA alleviation on the self-toxicity of pepper seedlings, the pepper ’Longjiao No.2’ seedling cultivated by the vermiculite perlite mixed medium was used as the material, and the soil and matrix extract Seedlings, the antioxidant enzyme activity, antioxidant and osmoregulation substances of pepper seedling leaves were studied under exogenous SNP (NO donor, 150μmol·L-1) and ABA (100μmol·L-1) Effect of membrane lipid peroxidation injury. The results showed that both soil and matrix extracts led to decreased activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), and dehydroascorbic acid (DHA) in leaves of pepper seedlings ; AsA, Pro, soluble protein and malondialdehyde (MDA) contents, as well as the relative conductivity and AsA / DHA increase; soil stress was significantly greater than that of the matrix extract. Exogenous NO and ABA treatment significantly increased the activities of SOD, POD and CAT, the content of Pro and soluble protein, the content of MDA and the relative conductivity of the leaves of pepper seedlings, significantly increased the content of AsA and the content of DHA, and maintained high AsA / DHA, NO alleviated oxidative damage of pepper seedlings under autotoxicity significantly better than ABA. The results showed that exogenous NO and ABA could effectively prevent the accumulation of MDA and leakage of electrolytes in pepper capsicum and alleviate the self-toxic effects on pepper seedlings by increasing the antioxidative enzyme activity, osmotic adjustment substance content and AsA / DHA ratio of pepper under autotoxicity Membrane lipid peroxidation, enhance pepper resistance.