Effect And Mechanism Of 24-epibrassinolide Treatment Maintain Kiwifruit Cold Storage Quality

Kiwifruit decays rapidly after harvest.Low temperature delays the process,but can cause chilling injury（CI）easily,which greatly limits the development of cold-chain storage and transportation.By using‘Huayou’kiwifruit as materials,the effect and the mechanism of 24-epibrassinolide（EBR）treatment on storage quality stored at low temperature were investigated in this report,to provide theoretical and technical basis for the application of EBR treatment in postharvest kiwifruit preservation.The results are as follows:（1）The effect of different concentrations of EBR(0,3,5,8 and 10μmol L^-1)treatment on kiwifruit stored at low temperature was studied,and the optimal concentration was selected.Results showed that EBR treatment at concertrations of 3,5 and 8μmol L^-11 could maintain storage quality of kiwifruit,and the best effect is obtained by 5μmol L^-11 EBR.Therefore,5μmol L^-1 EBR was selected to explore the mechanism of mitigation CI in postharvest kiwifruit.（2）The effect of EBR treatment on energy metabolism in kiwifruit was studied.Results showed that EBR treatment maintained higher adenosine triphosphate content and energy charge level in kiwifruit,which was related to the increase activity of succinate dehydrogenase,cytochrome C oxidase,H⁺-ATPase and Ca²⁺-ATPase.EBR guaranteed the balance between energy production and consumption,and thus showing a mitigating effect on CI in postharvest kiwifruit.（3）The effect of EBR treatment on polyamine and NO metabolism of kiwifruit was studied.Results showed that EBR treatment by regulating the content of arginine,ornithine and glutamic acid and the activity of arginine decarboxylase,ornithine decarboxylase,nitric oxide synthase,diamine oxidase and polyamine oxidase,EBR treatment kept the content of NO and polyamine in kiwifruit at relative high levels,thereby protecting kiwifruit from low temperature damage.（4）The effect of EBR treatment onγ-aminobutyric acid（GABA）and proline metabolism in kiwifruit was studied.Results showed that EBR treatment activated the activity of glutamate decarboxylase andΔ1-pyrroline-5-carboxylic acid synthase,while inhibited GABA transaminase and proline dehydrogenase activity,which accelerated the accumulation of GABA and proline,leading to an improved cold resistance in kiwifruit.