Effects Of SA Induced Resistance To Gray Mold And Storage Preservation In Postharvest Apple

The purpose of the present work was to investigate the effects of SA treatment on control of gray mold,and resistance mechanism of SA treatment on postharvest apple(‘ Red Fuji’ and ‘Gala’)gray mold by analyzing the changes of physiological and biochemical,as well as the preservation effects of SA treatment by soaking.The research results are as follows:1.0~250 mg/L of salicylic acid was significantly inhibited the growth of Botrytis cinerea in vitro,the effect might be closely associated with the concentration(the higher the concentration,the more obvious the effect).50、100 and 150 mg/L SA treatmet effectively reduced the incidence of gray mold rot,and inhibited the development of lesion diameter by B.cinerea,which 150 mg/L was the best effect.2.Different concentration of SA treatment significantly decreased the activity of catalase(CAT)and ascorbate oxidase(APX)at early period/stage after inoculation,promoted the synthesis of superoxide anion and hydrogen peroxide,induced the increase of peroxidase(POD)、superoxide dismutase(SOD)and glutathione reductase(GR),improved ascorbic acid(AsA)and glutathione(GSH)content,and limited the generation and accumulation of MDA.The results indicated that postharvest SA treatment enhanced the disease resistance of apple fruit by inducting of resistance defense response and regulating of active oxygen metabolism.3.150mg/L SA remarkably increased the activities of polyphenol oxidase(PPO),peroxidase(POD),phenylalanine ammonia-lyse(PAL),chitinase(CHI),β-1,3-glucanase(GLU),promoted the synthesis of total phenolics and flavonoids,and decreased the production of malondialdehyde(MDA),the incidence and the lesion diameter of gray mold rot by B.cinerea were effectively reduced,the results showed that SA treatment enhanced the disease resistance of apple fruit.4.SA treatment could reduce the respiration and ethylene release rate,regulate the activity of POD、PPO and SOD,inhibit the generation and accumulation of malondialdehyde(MDA),decrease the degree of membrane lipid peroxidation.The treatment also delayed the decline of fruit firmness,soluble solids content(SSC)and titratable acid(TA),and effectively reduced the weight loss rate of fruit to maintain the quality of apple at low temperature storage.