黄瓜采后外源褪黑素处理提高品质和延缓衰老的研究

以采后‘博耐35’黄瓜为试材,研究外源褪黑素浸泡处理对其10℃贮藏期间品质的影响及其机理。结果表明:外源褪黑素处理减缓了黄瓜贮藏过程中叶绿素、维生素C、可滴定酸、可溶性蛋白含量的下降速度,使黄瓜保持了更好的品质。进一步研究得出,外源褪黑素处理降低了黄瓜果实的相对电导率、丙二醛含量、活性氧含量及抗氧化酶(SOD、CAT、POD、APX)活性,降低了对细胞的氧化伤害,并抑制了呼吸速率和乙烯释放量,使细胞保持了更完整的结构,抑制了线粒体和叶绿体的形变。100μmol·L~(-1)的外源褪黑素处理可使黄瓜保持更好的品质,最大程度降低对细胞的氧化伤害,延缓了衰老,达到延长货架期的目的。

Postharvest Exogenous Melatonin Enhances Quality and Delays the Senescence of Cucumber

Cucumber is a kind of vegetable with short storage time(2-3 days)at ambient temperature.The objective of this study was to optimize postharvest melatonin handling conditions to reduce the quality loss and extend the shelf life of cucumber.The cucumbers were dipped in 0,50,100 or 500 μmol · L-1 melatonin solution immediately after harvest.Changes in quality index,chlorophyll concentration,vitamin C,tissue electrolyte leakage,MDA content,active oxygen content and activity of antioxidant enzymes were monitored periodically during storage at 10 ℃ forl5 days.Results indicated that exogenous melatonin treatment slowed down the decrease of chlorophyll,vitamin C,and the content of titration-acid and soluble protein of postharvest cucumber during storage.The further study showed exogenous melatonin treatment reduced the fruit relative conductivity,MDA content,active oxygen content and activity of antioxidant enzymes (SOD,CAT,POD,APX),and also inhibited the respiration intensity and the ethylene production,reduced the oxidative damage to cells and maintained a more complete cell structure.100 μmol· L-1 melatonin solution dip showed the highest overall quality,lowest tissue electrolyte leakage,MDA content,and maximum reduction of oxidative damage on the cells.