Effect of Alcohol on Active Oxygen Metabolism During Deastringent Treatment for Fruit of Persimmon cv.Zaohong

Fruits of persimmon cv.‘Zaohong'were treated with 40%and 30%alcohol respectively for deastringent treatment.The effect of alcohol on active oxygen metabolism in the fruits was investigated for the changes in the content of MDA、the rate of O-2net generation、the activities of SOD、POD、CAT and the content of Vc during deastringent period.The results indicated that,after the treatment,the tendency of MDA content was increased first then followed a descending.The higher of alcohol concentration,the greater of the MDA percentage was,and the less time to reach its peak value.The rates of O-· 2net generation were increase in first 48hours and the differences were indistinctive among the treatments.Thereafter,the rates of O-· 2net generation were decreased rapidly,especially in 40% alcohol treatment.The activity of SOD increased significantly,particularly in the later phase of deastringent treatment.The activity of POD descended slightly in beginning,then increased rapidly and followed with descended again.The higher alcohol concentration,the wider extent in change of up and down was. The activity of CAT was increase,but in 30% alcohol treated fruits,the CAT activity decreased after 48hour treatment.The content of Vc decreased rapidly in fruits treated with 40% and 30% alcohol for 24and 48hours, respectively,then the Vc content was maintained in constant level.During deastringent treatment,the changes in active oxygen content showed similar trend as the changes in tannin content,which indicated the positive effects of alcohol on deastringent treatment.The results also showed that the alcohol for deastringent treatment was stress to active oxygen metabolism and the alcohol could be the main factor of deastringency for persimmon cv.Zaohong.