龙眼果实采后果皮褐变和氧化胁迫的关系

Relationship between Pericarp Browning and Oxidation Stress in Postharvest Longan

本文通过双向电泳技术结合质谱分析的方法研究常温贮藏采后3 d的龙眼果皮蛋白,分离出800多个可重复蛋白,成功鉴定7个差异表达2倍以上并与氧化胁迫相关的差异蛋白,它们大都下调表达。其中,脱氢抗坏血酸还原酶和过氧化氢酶显著下调表达,表明龙眼果实采后3 d清除活性氧(ROS)的能力显著下降,导致细胞膜系统的完整性被破坏。同时,引起褐变的主要酶之一的过氧化物酶明显上调表达。这些结果表示,龙眼果实采后保持一定的抗氧化和清除ROS能力是延缓果皮褐变的重要措施。

In this study, tota l proteins extracted from postharvest longan（ Dimocarpus longan Lour.） pericarp stored at room temperature for 3 days were separated by two-dimensional electrophoresis（2-DE） and mass spectrometric analysis.More than 800 protein spots were detected. Seven protein spots related to oxidation stress were differentially changed in abundance by more than 2.0 fold in 2-DE gel and were successfully identified. Most of these proteins were down-regulated. And the dramaticall down-regulation of dehydroascorbate reductase and catalase during pericarp browning suggested that the ability of scavenging reactive oxygen species（ ROS） was decreased during longan fruit 3d-storage,which might damage cell membrane system and function. Otherwise, peroxidase, one of the main enzyme induced browning, was found to be significantly up-regulated. These results suggested that it was a vital measure to delay the browning of the fruits by keeping the capacity of antioxidation and scavenging ROS for postharvest longan fruit.