The Effect Of Strawberry Quality And Regulation Mechanism Of Nitric Oxide On Gery Mold Disease

Freshly harvested strawberry fruits ' HongYang ' were treated with 20 ?l/1 NO.To investigate the effects and potential mechanism of NO on postharvest physiology and quality,and the ability of diease resistance of strawberry.The active oxygen metabolism,phenylpropanoid metabolism and induced disease resistance of fruits were analyzed.The results were as follows:1.When exploring the effects of different NO treatment on decay and quality in strawberry fruit,we found that the NO at 20 ?l/L and SNP at 100 ?mol/L could suppress the occurrence of strawberry fruit rot.The higher concentration of NO and SNP were used,the more obvious inhibition effect was occured.However,the inhibition would be weakened when the concentration of NO was reached at 100 ?l/L and SNP was reached at 500?mol/L.In addition,NO concentration at 20 ?l/L and SNP concentration at 100 ?mol/L could maintain the antioxidant content and MDA accumulation effectively.Compared to the decay and quality of strawberry fruit treated by NO or SNP,these results suggest that NO treatment has a positive effect in the preservation of strawberry.2.The effects of NO fumigation on postharvest quality,the level of membrane peroxidation,the activity of phenylpropanoid metabolism related enzymes and the secondary metabolites of phenylpropanoid metabolism were analyzed.The results indicated that NO treatment at 20 ?l/L for 3 hours significantly inhibited the fruit decay,delayed the decrease of TSS,reduced membrane peroxidation and maintained fruit quality.Moreover,NO treatment at 20 ?l/L not only effectively enhanced the enzyme activities related to phenylpropanoid metabolism enzymes,such as 4-coumarate-CoA ligase,cinnamate 4-hydroxylase and chalcone isomerase,but also induced the accumulation of total phenolic,anthocyanin and flavonoid,and kept higher level of antioxidant activity.Therefore,our results suggested that 20 ?l/L NO treatment had a potential use for preserving better qualities in strawberry fruit.3.We analyzed the effect of NO treatment in delaying ripening,senescence and disease-resistance of strawberries,and found that the NO treatment at 20 ?l/L could improve the activity of antioxidant enzymes like SOD,CAT and APX in fruit,inhibit the increase of H2O2 content,the accumulation of MDA content and the activity of LOX,maintain a higher content of vitamine C,total phenol,total flavonoid and total anthocyanins,and enhance the activities of phenylpropanoid metabolism enzymes like PAL,C4H,4-CL and CHI.Besides,NO treatment at 20 ?l/L effectively increased the activity of disease resistance related enzymes like POD,PPO,GLU and CHT.These results suggest that NO treatment at 20?l/L could delay fruit senescence and inhibit fruit decay through maintaining the balance of active oxygen metabolism and phenylpropanoid metabolism.And we infered that the higher disease resistance of postharvest strawberry fruit might caused by the induce of priming.