Effects Of Selenium And Melatonin Treatments On Postharvest Gray Mold And Storage Quality Of Blueberry Fruits

Blueberry has a unique flavor,rich in nutrition,and broad development prospects.Due to the fact that the harvest season of blueberries is often a hot and rainy summer,they are susceptible to infection by pathogenic bacteria after harvest.Gray mold caused by Botrytis cinerea infection is one of the main diseases of blueberries after harvest.In addition,due to the characteristics of blueberry fruit itself,the quality of the fruit after harvest decreases rapidly and the storage period is extremely short.Selenium and melatonin can be used as plant growth regulators,providing good assistance to fruits and vegetables in resisting pathogen infection and maintaining postharvest quality.However,there are few studies on the regulation and preservation mechanism of selenium and melatonin on postharvest blueberry fruit gray mold.Therefore,this experiment used postharvest blueberry fruits as experimental materials,treated postharvest blueberry fruits with exogenous selenium and melatonin,and inoculated the treated blueberry fruits with Botrytis cinerea,to explore the inhibition of both on Botrytis cinerea and the changes in physiological metabolism of blueberry fruits;Analyze the effects of exogenous selenium and melatonin on the nutrients and storage quality of postharvest blueberry fruits by treating them with exogenous selenium and melatonin;To investigate the effects of exogenous selenium and melatonin treatment on the endogenous selenium and melatonin content in postharvest blueberry fruits.Provide theoretical reference for the preservation of postharvest blueberry fruits.The main research findings are as follows:1.Investigated the regulatory effects of exogenous selenium and melatonin treatment on postharvest gray mold of blueberry fruitIn the combination treatment group of 20 mg/L Se and 0.2 mmol/L MT,the results showed that the inhibition rate on the mycelial growth of Botrytis cinerea reached 97.61%,and the spore germination rate of Botrytis cinerea was only 10%.The compound treatment had a significant inhibitory effect on the incidence index and disease spot expansion of postharvest blueberry fruit.Compound treatment can induce an increase in the activities of CAT,SOD,POD,APX,and PAL in postharvest blueberry fruit,while inhibiting the activity of PPO and the accumulation of MDA,H₂O₂,and NO content,but has no significant improvement effect on GSH.2.The effects of exogenous selenium and melatonin treatment on the nutritional quality of postharvest blueberry fruit were analyzedIn the treatment of 20 mg/L Se combined with 0.2 mmol/L MT,the results showed a significant inhibitory effect on the decay and weight loss of postharvest blueberry fruit.Compound treatment can maintain the firmness of blueberry fruit,regulate the changes in pectin content,regulate the expression of cell wall degrading enzymes related genes Va PG and Va PME,thereby delaying the softening of blueberry fruit,while reducing the loss of nutrients such as TSS,SP,TPC,FC,and TAC,improving the activities of CAT,SOD,POD,and PAL,and inhibiting the accumulation of MDA,but has no significant improvement effect on As A.3.The nutritional fortification effect of exogenous selenium and melatonin treatment on postharvest blueberry fruit was testedCompared with the control group,the content of endogenous selenium and melatonin in blueberry fruits in the combination treatment group of 20 mg/L Se and 0.2 mmol/L MT significantly increased.