The Effect Of 2,4-epibrassionolide Treatment On Quality Maintenance In Postharvest Strawberry

Freshly harvested strawberry fruits 'HongYang' were treated with 5.0 ?mol/L 2,4-epibrassionolide.To investigate the effects and potential mechanism of 2,4-epibrassionolide on postharvest physiology and quality,and disease resistant ability of strawberry,the active oxygen metabolism,phenylpropanoid metabolism and induced disease resistance of fruits were analyzed.The results were as follows:1.We explored the effects of 2,4-epibrassionolide different treatment on decay of strawberry fruits,and found that the 2,4-epibrassionolide at 5.0 ?mol/L could suppress the occurrence of strawberry fruit rot.When the concentration of 2,4-epibrassionolide was reached 2.5 ?mol/L and 10 ?mol/L,the inhibition effect was weakened.In addition,2,4-epibrassionolide concentration at 5.0 ?mol/L could effectively maintain the antioxidant content.Compared to the decay and quality of strawberry fruit treated by different concentration,these results suggest that the 2,4-epibrassionolide at 5.0 pmol/L has a positive effect in preservation of strawberry.2.To investigate the effects of 2,4-epibrassionolide immersion on postharvest quality,the level of membrane peroxidation,the activity of antioxidant enzymes and the secondary metabolites of phenylpropanoid metabolism were analyzed.The results indicated that 2,4-epibrassionolide treatment at 5.0 ?mol/L for 5 minutes significantly inhibited fruit decay,delayed the decreases of TSS,reduced membrane peroxidation and thus maintained fruit quality.Moreover,2,4-epibrassionolide treatment 5.0 ?mol/L also effectively enhanced the activity of antioxidant enzymes,like superoxide dismutase,catalase and ascorbate peroxidase,induced the accumulation of total phenolic,anthocyanin and flavonoid,and kept high level of antioxidant activity.Therefore,our results suggested that 5.0 ?mol/L 2,4-epibrassionolide treatment had a potential use for preserving postharvest quality and maintaining high antioxidant activity of strawberry fruit.3.We analyzed the effect of 2,4-epibrassionolide treatment in delaying ripening,senescence and disease-resistance of strawberries,and found that the 2,4-epibrassionolide treatment at 5.0 ?mol/L could improve the activity of phenylpropanoid metabolism enzymes like PAL,4-CL and C4H in fruit,maintain the higher content of vitamine C,total phenol,total flavonoid and total anthocyanins.Inhibit the increase of O2·-content and the accumulation of MDA content.Besides,2,4-epibrassionolide treatment at 5.0 ?mol/L effectively increased the activity of disease resistance related enzymes like GLU and CHT.These results suggest that 2,4-epibrassionolide treatment at 5.0 ?mol/L can delay fruit senescence and inhibit fruit decay through maintaining the activity of phenylpropanoid metabolism related enzymes and enhancing disease resistance in postharvest strawberry fruit.