Effect Of 24-epibrassionlideon Resistance To Gray Mold Andstorage Of Red Golobe Grape

Due to the large amount of vitamins,minerals,sugar,organic acids and other nutrients,table grapes have a high nutritional value.However,the grapes are prone to diseases during transportation and storage after harvest,and cause serious losses to the commercial value of the fruits.In particular,Botrytis cinerea grows easily under low temperature storage conditions.Therefore,in the aspect of storage and preservation of fresh grapes,no pollution is a research hotspot in the field of grape preservation at home and abroad.In this experiment,Red Globe and Botrytis cinerea were used as materials.The in vitro inoculation of Botrytis cinerea with grape fruit,different concentrations of 24-epibrassinolide（EBR）（0.1 mg/L,0.4 mg/L,and 0.8 mg/L）on the quality of grape during ripening and during fruit coloring,1 d pre-harvest and post-harvest treatment of 0.4 mg/L EBR on the storability of grapes were studied,in order to provide a theoretical basis for grape storage preservation.The results of the study are as follows:（1）The application of different concentrations of EBR at verasion can increase the fruit’s vertical diameter,transverse diameter,and weight of the grape.It can also improve the TSS,reducing sugar,sugar-acid ratio,brrry turning rate and anthocyanin quality indicators,reduce the TA,improve the taste of the fruit taste.One week after the treatment with different concentrations of EBR had the greatest impact on the above-mentioned shape indicators and quality indicators.Overall,0.4 mg/L EBR treatment had the most effective in improving the physiological quality of grape fruits during the whole ripening of grapes.（2）After inoculation with Botrytis cinerea,compared with control（CK）,the 0.4 mg/L EBR treatment could inhibit the growth of Botrytis cinerea and reduce the incidence of grape and the sporulation rate.The average CK reduction was 27.42%and 81.55%,respectively.After 0-8 days of inoculation with Botrytis cinerea,0.4 mg/L EBR treatment could reduce the Malonaldehyde（MDA）and super cations(O₂^·-)content of fruit.The average decreases by34.71%and 89.32%respectively compared with CK.Compared with CK,EBR treatment can increase the activity of Polyphenol oxidase（PPO）,peroxidase（POD）,chitinase（CHT）andβ-1,3-glucanase（GLU）,and the average CK increased by 12.42%,37.90%,25.36%and36.60%,respectively.The EBR has no direct bacteriostatic effect on Botrytis cinerea,but it can activate the grape’s natural defense system to increase the berry’s resistance to disease by inducing the activity of disease-resistant enzymes in the living grape.（3）Grapes storage of 0-60d,EBR treatment at veraison,at 1 day before harvest and at postharvest can reduce the rate of grain drop,rot rate,water loss rate,browning index of fruit stems,relative electrical conductivity of fruit stems.It can also inhibite the grapes softening,decrease TSS,TA and chlorophyll of fruit stems,slowing the grape’s respiratory intensity.Overall,postharvest EBR treatment has the most obvious effect on maintaining the appearance quality of grape storage and reducing post-harvest physiological activity.EBR treatment reduced the content of O₂^·-and MDA during grape storage in different periods.O₂^·-and MDA in the whole storage cycle was the lowest in the post-harvested grape,which was lower than the CK by 27.45%and 17.83%respectively.After 0-60 d storage of grapes,EBR treatment could increase the activities of defense enzymes in SOD,CAT,POD and PPO,and the effect of EBR treatment on the activity of disease-resistance related enzymes was the most obvious.In summary,EBR has no direct bacteriostatic action against Botrytis cinerea,but activates the plant’s natural defense system by inducing the activity of resistance-related enzymes in the fruit to increase the plant’s disease resistance.The 0.4 mg/L EBR treatment at verasion period has a greater effect on the grape quality during the ripening process of grapes.During the course of grape storage,the EBR treatment at verasion period could maintain the higher nutritional value and taste quality of the fruit.For the whole storage period of grapes,post-harvest EBR treatment delays grape senescence,reduces morbidity,and improves storage stability.