Effect of the Harvest Time on the Active Oxygen Metabolism of Dragon Fruit during Its Storage Period

[Objective]The rule of the variation of active oxygen metabolism of the dragon fruit,harvested at different times,during its storage period was investigated.[Method]The effect of different harvest times on the active oxygen metabolism of dragon fruit-Baiyulong during storage at room temperature was studied.[Result]The earlier the harvesting time(the 21th day after florescence) of the dragon fruit was,the higher the activity of SOD,CAT and POD was and the earlier the peak of their activities appeared,however,the lower the content of MDA and O-2· and the permeability of membrane were.The fruit later the harvesting time(29th day after florescence) of the dragon fruit was,the lower the activity of CAT was,the lower the activity of SOD and POD was in early storage,the higher the activity of POD was in late storage,the higher the content of O-2·and MDA and the permeability of membrane were.The appropriate harvesting time(25th day after florescence) could result in the meddle value in the SOD,POD and CAT activities,MDA content and membrane permeability of the fruit were in between,O-2·content was significantly reduced.[Conclusion]The fruit harvested on the 25th day after florescence could significantly reduce the accumulation of O-2·and have high protective enzyme activity.