Research of stress defense response to jasmonic acid methyl ester( Me JA) and ethephon for cold storage fresh-cut pumpkin

Fresh- cut pumpkin was taken as material. Jasmonic acid methyl ester( Me JA) and ethephon were used as signals to treat fresh- cut pumpkin,and stored at 4 ℃.Free radical scavenging systems tool enzymes including peroxidase( POD),catalase( CAT),ascrobate peroxidase( APX),superoxide dismutase( SOD),H2O2 content and polyphenol oxidase( PPO) activity were analyzed to study mechanical damage stress adaptability of defense response of these two signal molecules on fresh- cut pumpkin.The results showed that POD,SOD and APX activity were reduced by ethephon and Me JA,CAT activity was maintained,the accumulation of H2O2 was reduced and PPO activity was inhibited significantly( p < 0.05) by two treatments. Jasmonic acid methyl ester( Me JA) and ethephon could start defense response to wounding by inducing activities of free radical scavenging system tool enzymes.The effect of ethephon was more remarkable.