Effect Of AVG And 1-MCP Treatment On Fruit Quality And Physiological Characteristics During Muskmelon Storage

Melon(Cucumis melo L.)is an important horticultural crop in the world.Muskmelon(Cucumis mel o L.var.reticulatus Nand)is popular for consumers because of its good appearance,unique flavor and aroma.However,it is a climacteric fruit,flesh firmness decreased sharply during storage and transport at room temperature,which resulted in losses of nutrition composition and product quality,shorten shelf life,and became a bottleneck of melon industry.The melon variety ‘Xiangmier' was used in this experiment,Experimental treatments as followings: 1.Comparison of harvest times: fruits were harvested at 43 days and 46 days after pollination(DAP),respectively.2.Different concentration treatments of AVG(ethylene synthesis inhibitor): fruits were sprayed with 50mg/L AVG,100mg/LAVG,200mg/L AVG and 300 mg/L AVG at 35 DAP,respectively,sprayed with water as control(CK),and then were harvested 43 days after pollination(DAP).3.Different time treatments of AVG: fruits were sprayed with 100mg/L AVG at 33 DAP and at 41 DAP,respectively,sprayed with water as control(CK),and picked 46 days after pollination(DAP).The above fruits treated were storied at temperature of 18?~20?with 80~85% relative humidity.4 Different treatments of 1-MCP,AVG and temperature combinations1)fruits sprayed with 100mg/L AVG at 33 DAP,sprayed with water as control(CK),and harvested 46 days after pollination(DAP).2)Fruits harvested 46 days after pollination(DAP),then fumigated with 1?L/L 1-MCP(ethylene action inhibitor)for 24 hours at room temperature,ventilated for 0.5h.3)Fruits harvested 46 DAP,sprayed with water at 33 DAP,as control(CK).The above fruits were divided into two groups,the one was in storage temperature of 18 ?~ 20? with 80~85% relative humidity,the other was in storage temperature of 9 ?~12 ? with 80~85% relative humidity.The physiological properties were investigated,including the changes of fruit quality,ethylene synthesis,active oxygen metabolism and its related enzymes activity during storage,in order to select suitable storage parameters for melon,to guide the postharvest handling of melon.The main results are as follows:1.During storage at room temperature,the flesh firmness and total soluble solid content of melon fruits declined rapidly in earlier storage,and declined slowly in later storage.After 10 days storage and 2 days shelf life,the difference was significant(p=0.05).The irritable acidity and Vitamin C content of melon fruit decreased gradually,the titratable acid(TA)content decreased and ethylene peak of fruits 46 DAP were delayed 3 days.The VC content of fruit had no difference.The results showed: the fruits picked 46 DAP could keep optimum quality for melon.2.AVG treatment retarded the decreasing of flesh firmness and soluble solids content at room temperature.After 13 days storage,compared with other treatments,soluble solids content of 100 mg/LAVG treatment was significant higher than that of the others(P=0.01).But flesh firmness was no significant difference between AVG treatment and control.AVG treatment could reduce respiration intensity,significantly inhibit ethylene production of melon(P=0.01).In those trial treatments,fruits treated by100 mg/LAVG were optimum for melon storage.3.Compared with control,two treatments time of AVG significantly retarded the decreasing of H* values and kept the green of epicarp better,inhibited the decreasing of flesh firmness,TSS content in earier storage and respiration intensity.AVG also suppressed ethylene production,activity of ACS,ACO(ethylene synthesis related enzyme)and accumulation of ACC content(P=0.05).AVG treatment 33 DAP is better in this trial.But two treatments time of AVG had no significant difference between TA content and Vitamin C content4.During storage at room temperature,the some characteristics gradually decreased,including(flesh firmness,TSS content,TA content,Vc content and H* values of epicarp).Compared with control,AVG and 1-MCP treatment significantly inhibited the decreasing of H*value during later storage.But the effect of two treatments on TSS,TA and Vitamin C content were no significant difference.Low temperature could inhibit the decreasing of flesh firmness and TSS,TA and Vitamin C content and H* values of epicarp.Compared with control,AVG?1-MCP treatment significantly inhibited the flesh firmness and H* values of epicarp during later storage at low temperature,At room temperature,AVG treatment could reduce respiration intensity.AVG and 1-MCP treatments inhibited the increasing of ACS activity,ACO activity and accumulatiion of ACC,significantly reduced ethylene production(P = 0.05).At low temperatures,compared with the control,the effects of AVG and 1-MCP treatments had the same change,including respiration,ethylene production,the ACS,ACO activity and accumulation of ACC.During storage at room and low temperature,AVG and 1-MCP treatment could maintain a high POD?SOD?CAT activity,inhibit the accumulation of MDA content in melon fruit.Low temperature also could effectively maintain POD?SOD activity at high level.5.The appropriated storage parameters for muskmelon ‘Xiangmier' were as follow:fruits sprayed with 100 mg / L AVG,about 5 weeks after pollination,harvested after pollination 43~46 days,storage temperature was 18?~20?with 80~85% relative humidity,storage life is about 10~14 days,the shelf life is about 2 days;While storage temperature was 9~12 ?with 80~85% relative humidity,storage life is up to 20-25 days,the shelf life is about 3 days.6.The appropriated storage parameters for muskmelon ‘Xiangmier': fruits picked after pollination 43~46 days,fumigated with 1 ?L/L 1-MCP(ethylene action inhibitor)for 24 hours at room temperature,ventilated 0.5 h,storage temperature were 18?~20?with 80~85% relative humidity,storage life is up to 10~14 days,the shelf life is about 2 days;While storage temperature was 9~12 ?with 80~85% relative humidity,storage life is up to 20-25 days,the shelf life is about 3 days.