Research On The Control Effect And Pathogenesis Of Resveratrol On Black Skin Disease Of Dangshan Pear

Superficial scald,a serious physiological storage disorder of pears which usually appears in the later storage period,greatly reduces the commercial value of the fruit.In this investigation,we chose the 'Dangshansuli'pear?Pyrus bretschneideri,Rehd.?as the experimental material.In order to reduce the incidence of superficial scald,we made Res treatment,further,by comparing with the effects of 1-MCP and DPA treatments,we explored the influence of ?-farnesene metabolism and antioxidant capacity to superficial scald during cold storage,and studied the relationship between superficial scald and the expression of PFS gene and the PPO gene,then revealed the possible mechanism that resveratrol could control superficial scald.The results are as follows:1.Res treatment can significantly control the superficial scald occurs of'Dangshansuli' pear.At the end of cold storage,the incidence of superficial scald was 18.2%and superficial scald index was 8.2%,while pears treated the Res,1-MCP and DPA had no disease.After 10 days shelf life at 25 ?,the incidence of superficial scald in control rapidly increased to 91.5%,superficial scald index rose to 75.3%,while the Res,1-MCP and DPA treated specimens respectively were 26.2%,12.0%and 30.0%,and superficial scald index were 11.1%,9.0%and 13.0%.The results show that Res treatment can control the occurrence of superficial scald significantly,and the effect is of treatment is equal to DPA.2.During the whole cold storage,the content of ?-farnesene increased first and then decreased,the peak of content occurred on 120th day numerically 27.2 nmol·cm-2.while after the resveratrol treatment,the peak appearance delayed to 150 days and the date decreased to 25.3 nmol·cm-2.At the same time,the change of relative expression of PFS gene was similar to the content of ?-farnesene.The results show that 1-MCP significantly inhibited the expression of PFS gene,while Res treatment delayed and reduced peak of PFS gene expression.So can we infer that by reducing and delaying PFS gene expression to reduced ?-farnesene is one of the reasons that Res prevented the superficial scald.3.The content of conjugated triene in the 'Dangshansuli'pear straightly increased during the cold storage.As the results,The content of conjugated triene with DPA and Res treatment was significantly lower than 1-MCP and CK treatment on 210th day.However,there is no significant difference between the DPA and Res.So We infer that Res inhibit the conversion of ?-farnesene to conjugated trienes is the other reason that Res prevents the superficial scald.4.During cold storage,the content of total phenols increased gradually.The first peak of PPO activity appeared after 120 days,then the activity began to decline,and reached a maximum after 210 days.The control group was 7.4 U·g^-1 FW·min^-1 which was significantly higher than the other treated groups.Res,1-MCP and DPA treatments can effectively reduce the total phenolic content and inhibite PPO activity,In Res treatment groups,PPO activity decreased to 5.8 U·g-1FW·min-1.In the research,by probing the gene expression of PPO we found PPO gene expression had been the lowest in 1-MCP treatment,Res and DPA treatments have no significance difference.Res can inhibit gene expression and reduce PPO activity,thus prevent the superficial scald.5.The production rate of O2-·and H₂O₂ content will be increased during in cold storage.they were significantly higher than the other groups in control group;and the SOD,CAT,POD activity also changed in cold storage.In the first 90 days,SOD,CAT,POD activity reached the first peak,and they were also significantly lower than the treatment groups in cold storage period.We can infer that Res,1-MCP and DPA enhance SOD,CAT,POD activity and reduce the generation of reactive oxygen to reduce the incidence of superficial scald.In this study,It was confirmed 1-MCP was the best preservative,the effect of Res is equal to DPA.