1-MCP处理对西葫芦果实线粒体抗氧化作用和能量代谢的影响

Effects of 1-MCP on the Mitochondrial Antioxidant Activity and Energy Metabolism of Zucchini Fruits

为探究1-甲基环丙烯(1-methylcyclopropene,1-MCP)处理对西葫芦果实常温贮藏条件下线粒体活性氧代谢和能量代谢的影响,以‘泰山绿’西葫芦为试材,采用20μL·L^(-1)的1-MCP在室温下熏蒸24 h后将其置于常温(20±1)℃下贮藏12d,贮藏期间每3d测定西葫芦果实的生理品质、线粒体抗氧化特性和能量代谢变化。结果表明,贮藏结束时的第12d,1-MCP处理西葫芦果实失重仅为对照的54.6%,总酚含量为对照的1.44倍;贮藏期间,果实的呼吸强度显著(P<0.05)低于同时期对照果实(>10 mg·kg^(-1)·h^(-1)),1-MCP处理还降低了西葫芦线粒体丙二醛和过氧化氢含量、抑制了超氧阴离子产生速率,在第6、9 d,处理果实的过氧化氢含量、超氧阴离子产生的速率分别比对照组低了17.45%、23.29%和10.51%、7.62%。1-MCP处理使西葫芦果实线粒体维持了较高的超氧化物歧化酶、抗坏血酸过氧化物酶活性,降低了脂氧合酶的活性,贮藏至第3d和第6 d,处理组线粒体超氧化物歧化酶活性是对照组的1.23、1.15倍。此外1-MCP处理还延缓了琥珀酸脱氢酶、细胞色素C氧化酶、线粒体H^(+)-ATPase、线粒体Ca^(2+)-ATPase活性的下降。贮藏第6d,1-MCP处理的西葫芦果实后四种酶的活性都显著高于对照(P<0.05),H^(+)-ATPase、Ca^(2+)-ATPase分别是对照的1.05和1.22倍。因此得出结论,1-MCP可以通过减轻西葫芦果实线粒体膜氧化损伤,保持线粒体的完整性,延缓成熟衰老进程,有利于延长西葫芦果实贮藏期。

In order to explore the effects of 1-methylcyclopropene(1-MCP)treatment on mitochondrial reactive oxygen metabolism and energy metabolism of zucchini fruits stored at room temperature,this study took‘Taishan Green’zucchini as test materials.The fruits were fumigated with 20μL·L^(-1)1-MCP at room temperature for 24 h and then stored at room temperature(20±1)℃ for 12 d.The physiological quality,mitochondrial antioxidant properties and energy metabolism change of zucchini fruits were determined every 3 d during storage.Results showed that:On the 12th day at the end of storage,the weight loss of 1-MCP treated zucchini fruit was only 54.6% of that of the control,and the total phenol content was 1.44 times of the control.During storage,the respiration intensity of fruits was significantly lower than that of control fruits(>10 mg·kg^(-1)·h^(-1))(P<0.05),1-MCP treatment also decreased the content of malondialdehyde and hydrogen peroxide in mitochondria of zucchini and inhibited the production rate of superoxide anion.The hydrogen peroxide content and superoxide anion production rate of the treated fruits were 17.45% and 23.29% lower and 10.51% and 7.62% lower than those of the control group,respectively.1-MCP treatment kept the activities of superoxide dismutase and ascorbate peroxidase higher in mitochondria of zucchini fruits,decreased the activities of lipoxygenase.The mitochondrial superoxide dismutase activity in the treatment group was 1.23 and 1.15 times of that in the control group at the 3rd and 6th day of storage.In addition,1-MCP treatment also delayed the decrease of the activities of succinate dehydrogenase,cytochrome C oxidase,mitochondrial H^(+)-ATPase and mitochondrial Ca^(2+)-ATPase.On the sixth day of storage,the activities of four enzymes of zucchini fruits treated with 1-MCP were significantly higher than those of the control(P<0.05),the activities of H^(+)-ATPase and Ca^(2+)-ATPase were 1.05 and 1.22 times than those of the control.Therefore,1-MCP could reduce the oxidative damage of mitochondrial membrane of zucchini fruits,maintain the integrity of mitochondria,delay the process of maturation and senescence,and prolong the storage period of zucchini fruits.