乙醇对‘早红’柿果实脱涩过程中若干活性氧代谢指标的影响

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

以南方早熟涩柿‘早红’为材料,对其进行40%、30%两种乙醇浓度的脱涩处理,通过对这一过程MDA含量、O-·2净产生速率、SOD、POD、CAT活性及抗氧化物质Vc含量变化的研究,探讨乙醇对其活性氧代谢的影响,结果表明:乙醇脱涩处理后MDA含量有一个先上升后下降的过程,且浓度越高、MDA含量越高,到达峰值的时间越短;O-·2净产生速率在前48h上升,处理间基本没差异,但在此后的下降过程中,乙醇浓度越高下降越快;SOD酶活性增大,脱涩后期增大更明显;POD酶活性经历一个小幅下降然后快速上升进而再下降的过程,乙醇浓度越高,其上升和下降的幅度都越高;CAT酶活性增大,但30%乙醇脱涩48h后的CAT酶活性开始下降;40%乙醇脱涩处理24h、30%乙醇脱涩处理48h后,果实抗氧化物质Vc含量开始快速下降,然后2个处理都基本维持在一个恒定的水平。乙醇脱涩过程活性氧代谢指标的变化,不仅证明了乙醇在脱涩过程中的积极作用,而且与脱涩过程单宁含量变化趋势相一致,也符合活性氧代谢相关理论,表明乙醇脱涩确实是一个胁迫过程,乙醇是‘早红’柿果脱涩过程活性氧代谢的主要影响因素。

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 O2- net 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 O2·- net generation were increase in first 48 hours and the differences were indistinctive among the treatments .Thereafter ,the rates of O2·- net 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 48 hour treatment .The content of Vc decreased rapidly in fruits treated with 40% and 30% alcohol for 24 and 48 hours , 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 .