Effect Of Preharvest Spraying Salicylic Acid On The Resistance Of Grey Mold And Quality In Red Globe Grape

Red Globe Grape(Vitis vinifera L.cv.Red Globe Grape)is one of the main varieties in Xinjiang.Grape fruit is very susceptible to fungal infection and rot during storage and transportation after harvest.Botrytis cinerea caused by Botrytis cinerea is the main fungal disease after grape fruit harvest.Salicylic acid(SA)treatment can maintain the hardness and quality of grape berries,resist the infection of pathogenic bacteria,and reduce the decay rate of the fruit during storage.In this study,Red Globe grapes were used as the research material,and SA was sprayed in the three stages of grape fruit growth and development,starting from two aspects of postharvest quality maintenance and postharvest disease control,to study the effects of preharvest SA treatment on grape fruit quality Analyze the influence of grape fruit cell wall metabolism on postharvest softening,and clarify the degradation of propectin into pectic acid and carbohydrates caused by changes in the activities of main pectinase activities such as PG,PME,?-Gal,?-Glu and Cx The effect of disease control after injury inoculation with Botrytis cinerea is explored,and the disease resistance mechanism of SA treatment is analyzed from the aspects of phenylpropane metabolism-related enzyme activities,resistance-related substances,and VvPAL family gene expression patterns.At the same time,the SA treatment is studied.The effect of shelf life.The main findings are as follows:(1)Spraying 0(CK of distilled water in the same volume),0.5,1.0 and 2.0 mmo L/L salicylic acid(SA)to treat grape berries during the expansion period,color conversion period and pre-harvest period(2 days before harvest).Preharves spray t SA can delay the increase of rot rate,shattering rate,stem browning and weight loss rate of grape fruit,and delay the decrease of fruit hardness.Maintain the soluble solids and titratable acid content in grape berries.1.0 mmo L/L SA is a suitable spray concentration,which can increase the activity of PAL,CAT,PPO and GLU and maintain the storage quality of Red Globe grapes.(2)To study the inhibitory effect of spraying 1.0 mmo L/L SA before harvest on the growth of Botrytis cinerea after grape harvest and the effects of enzyme activities related to phenylpropane metabolism.Spraying SA before harvest can reduce the morbidity and lesion diameter of grape berries after inoculation with Botrytis cinerea,promote the accumulation of TP and TF,increase the activity of PAL,C4H and 4CL in grape berries,and up-regulate the expression of VvPAL,VvC4H and Vv4CL genes.Improved the resistance of grape berries to post-harvest gray mold disease.Through comparison,it was found that VvPAL played a dominant role.(3)To study the effect of spraying 1.0 mmo L/L SA before harvest on the relative expression of VvPAL family genes after grape injury inoculation with Botrytis cinerea.SA can induce the up-regulation of VvPAL family genes in grapes,and the relative expression of VvPAL genes in grape peels.The speed is low.The relative expression of VvPAL gene in the pulp is up-regulated faster,and the expression of VvPAL2,VvPAL3,VvPAL4,VvPAL9,VvPAL12,VvPAL13 and VvPAL17 in the pulp is up-regulated faster.This induction phenomenon is more significant in the middle and late stages of storage.By comparing 0 d,the relative expression of VvPAL1-PAL17 gene in peel was higher than that in pulp.(4)To study the effect of spraying SA before harvest on the cell wall metabolism of grapes after harvest.SA can delay the decrease of PP and cellulose content in grape berries,increase the content of WSP,and delay the activities of PG,PME,?-Gal,?-Glu and Cx Increased,inhibited the expression of VvPG,VvPME,Vv?-Gal,Vv?-Glu genes,thereby further delaying the softening of grape berries after harvest.(5)Study the effect of spraying SA treatment before harvest on the shelf life of grape berries.Pre-harvest spraying SA can delay the increase of MDA,relative conductivity,weight loss rate,decay rate and browning index of stalk,delay the decline of ASA and sensory quality,and increase the content of TSS and TA.Through comparing the weight loss rate,rot rate,browning index and sensory quality of grape fruit,it was found that SA could delay the shelf life 2-3 d.It shows that spraying SA treatment before harvest can improve the quality of the fruit.Reduce the economic loss caused by rot and other problems during the sale of grapes after harvest,and extend the shelf life of grapes.