Effect Of 1-MCP And MeJA On Quality And Disease Resistance In Chinses Bayberry Fruit

In this study, the decay incidence and quality changes in Chinese bayberry fruit (Myrica rubra Sieb.et Zucc. Duchesne.Wu Zhong) treated with 1-methylcyclopropene (1-MCP) and methyl jasmonate (MeJA) for 4 hours at 20℃during storage at 1℃for 15 days or at 20℃for 60 hours were investigated .The results were as follows:1. Treatments with 250 or 500nl/L 1-MCP had no significant effects on decay incidence, weight loss, TSS, TA, vitamin C, anthocyanin contents and firmness in Chinese bayberry fruit during storage both at 1℃and 20℃. 1000 nl/L 1-MCP treatment promoted fruit decay incidence and declines of TA and fruit firmness during storage, but had little effect on other quality parameters. These results suggest that treatment with 250 and 500nl/L 1-MCP had no obvious effect of keeping Chinese bayberry fresh, and 1000 nl/L 1-MCP even increased the decay incidence. Therefore the treatment of 1-MCP has no applicable value.2. Treatment of 1 and 10μmol/L MeJA significantly inhibited Chinese bayberry decay incidence, and the effect of these treatments was more pronounced in fruit stored at 20℃than those stored at 1℃. 1 and 10μmol/L MeJA treatments also maintained higher levels of TSS, TA and vitamin C contents, and promoted the accumulation of anthocyanin in bayberry fruit, and had little effect on weight loss and fruit firmness. However, 100μmol/L MeJA treatment had no effect on decay incidence, weight loss and quality changes. The results suggest 1 and 10μmol/L MeJA treatments could inhibit fruit decay incidence and maintain the fruit quality, therefore of commercial use in prolonging the storage life.3. Treatment with 1000 nl/L 1-MCP significantly increased decay incidence in Chinese bayberry fruit, inhibited the accumulation of total phenolics and PPO, POD activities but had no effect onβ-1,3-glucanase and chitinase activities. These results indicate that the increasing decay incidence treated with high concentration 1-MCP is related to the reduction of defensive enzyme activities. The fruit treated with 10μmol/L MeJA showed lower incidence of decay and higher levels of total phenolics and PAL, POD,β-1,3-glucanase and chitinase activities, which might account for higher disease resistance and lower decay index in MeJA treated fruit.4. 10μmol/L MeJA significantly inhibited decay incidence and the increase in relative conductivity, maintained higher levels of SOD and CAT activities and Vc content, inhibited the increases in superoxide radical production. 1000nl/L1-MCP significantly promoted decay incidence and the increases in relative conductivity and superoxide radical production. These results indicate that the 10μmol/LMeJA may maintain the balance of active oxygen metabolism, thereby delaying fruit senescence and inhibiting fruit decay, whereas 1000nl/L1-MCP destroyed this balance and promotd the decay incidence in Chinese bayberry fruit.