外源褪黑素降低黄瓜体内霜霉威残留的生理生化分析

为探究褪黑素(melatonin,Mel)对黄瓜体内农药降解中的调控作用,以黄瓜‘Y3F604’为材料,以氨基甲酯类农药霜霉威(C₉H₂₀N₂O₂)为处理试剂,采用灌根的方法研究外源施用1 mmol/L Mel对黄瓜体内霜霉威残留的影响,同时探究O₂^-·、H₂O₂、MDA、GSH和GSSG含量以及抗氧化酶和解毒酶的变化情况。结果表明,外源1 mmol/L的Mel处理显著降低了霜霉威处理48 h后黄瓜体内的霜霉威残留量。在霜霉威胁迫下,黄瓜叶片中O₂^-·、H₂O₂和MDA的含量明显增加,而外源Mel处理能够有效抑制霜霉威胁迫下黄瓜体内的O₂^-·、H₂O₂和MDA积累。与对照相比,外源Mel处理显著提高了霜霉威胁迫下SOD、CAT、POD、APX、GPX等抗氧化物酶活性,进一步促进GSH含量和总谷胱甘肽含量的增加,提高GSH/GSSG、GST与GR解毒酶活性。因此,外源施用Mel可提高黄瓜在霜霉威胁迫下的抗氧化能力和解毒能力,从而加速黄瓜体内霜霉威的代谢,是促进蔬菜残留农药降解的新途径。

Physiological and Biochemical Analysis of Exogenous Melatonin for Reducing Propamocarb Residues in Cucumber

In order to explore the regulation effect of melatonin (Mel) on degradation of residual pesticide in cucumber, cucumber variety ‘Y3F604’ was taken as test material and the carbamate pesticide propamocarb (C₉H₂₀N₂O₂) was applied to study the effect of 1 mmol/L Mel on propamocarb residues by irrigating the root. At the same time, the content of O₂^-·, H₂O₂, MDA, GSH and GSSG, and the change of antioxidant enzymes and detoxification enzymes after the application of propamocarb were investigated. The results showed that the exogenous application of 1 mmol/L Mel significantly reduced pesticide residues in cucumbers after the propamocarb treatment for 48 h. Under the stress of propamocarb, the content of O₂^-·, H₂O₂ and MDA in leaves increased significantly, while exogenous Mel treatment could effectively inhibit the accumulation of O₂^-·, H₂O₂ and MDA in cucumber. Compared with the control, exogenous Mel treatment could significantly increase the activity of cucumber SOD, CAT, POD, APX and GPX under the stress of propamocarb, and further increase the content of GSH and total glutathione, the ratio of GSH/GSSG, as well as the activity of GST and GR. Therefore, exogenous Mel treatment could induce the ability of antioxidant and detoxification under the stress of propamocarb, thus promoting the metabolism of propamocarb in cucumber. This study provides a new way to promote the degradation of pesticide residues in vegetables.