Effect On Energy Metabolism,Membrane Lipid Metabolism And Disease-resistant Material Metabolism In Harvested ’Zhaoxia’ Peach Fruit By 1-MCP Treatment

Peach(Prunus persica L.)originated in China,and be known as the ’The best fruit’,which has thin skin,flesh thick,elegant flavour and nutrient-rich.Peach fruit are exuberant at postharvest physiology and metabolism,that the high temperature and humidity at its harvested season causes which is subjected to mechanical damage easily,unfavorable for storage and high incidence,then it has a serious impact on its long-distance transportation and sales.Prach fruit stores at room temperature which putresces in 2 to 3 days,and is downright rotten in 5 to 7 days.1-methylcyclopropene(1-MCP)is a new type of efficient ethylene receptor inhibitor which is harmless to humans and friendly to environment,therefore it delays the senescence of fruit and prolongs shelf period.Our previous reasearches has found that 1.2 μL·L-1 of 1-MCP treatment had significant effects on deferring senility of harvested peach fruit,but it is still unclear that the occurrence mechanism.Thus,upon the previous researches,this subject uses ’Zhaoxia’(Prunus persica L.cv.’Zhaoxia’)fruits which is the major peach cultivar in Fujian province as the experimental material.This research focus on studying the effect on energy metabolism,membrane lipid metabolism and disease-resistant material metabolism,and elaborated the probable action mechanism of delaying senescence and improving disease-resistance in harvested ’Zhaoxia’ peach fruit by 1-MCP treatment.The results as followed:1.Effect of harvested ’Zhaoxia’ peach fruit on energy metabolism by 1.2 μL·L-11-MCP treatment.Compared with the control fruits,results indicated that the treatment of 1.2 μL·L-1 1-MCP maintained relatively higher content of adenosine triphosphate(ATP),adenosine diphosphate(ADP)and energy charge(EC),and reduced the adenosine monophosphate(AMP)content and activity of cytochrome c oxidase(CCO).Meanwhile,’Zhaoxia’ peach fruits treated with 1-MCP enhanced higher activity of H+-ATPase,Ca2+-ATPase,Mg2+-ATPase and NAD kinase(NADK),kept higher content of NADP(H),and controlled accumulation of NAD(H)content.Among above,it draw a conclusion that 1-MCP treatment maintained higher energy level,thus inhibited fruit senescence.2.Effect of harvested ’Zhaoxia’ peach fruit on membrane lipid metabolism by 1.2 μL·L-1 1-MCP treatment.Compared with the control fruits,results indicate that the treatment of 1.2 μL·L-1 1-MCP reduced cell membrane permeability,decreased the activities of phospholipase D(PLD),lipase and lipoxygenase(LOX),advanced the relative content of unsaturated fatty acid,such as oleic acid,linoleic acid and linolenic acid,and blocked the relative content of saturated fatty acids to increase,such as palmitic acid,stearic acid and arachidic acid,and maintained higher index of unsaturated fatty acid(IUFA)and unsaturated degree of fatty acid(U/S).Among the above,it draw a conclusion that 1-MCP treatment restrained activities of membrane lipid-degrading enzymes,and kept higher unsaturated fatty acid content,increased IUFA and U/S,thus defended membrane system function and integrity of cytomembrane structures,and delayed the senescence of fruit.3.Effect of harvested ’Zhaoxia’ peach fruit on disease-resistant material metabolism by 1.2 μL·L-1 1-MCP treatment.Compared with the control fruits,results indicate that the treatment of 1.2 μL·L-1 1-MCP accelerated higher activities of chitinase(CHI)and β-1,3-glucanase(GLU),phenylalanine ammonia-lyase(PAL),polyphenol oxidase(PPO)and peroxidase(POD),enhanced phenolics content,such as lignin and total phenolic.Among the above,it draw a conclusion that 1-MCP treatment increased activities of resistance-related enzymes effectively,sustained higher content of phenolics,thus enhanced the disease resistance,reduced disease index and suspend the fruit senescence.