| In this paper,the harvested fruit of Syzygium samarangense Merr.et Perry was selected as the experimental material to study the effects of nitric oxide(NO)treatment on physiological quality and sugar metabolism of this fruit.Methanol-water and methanol-chloroform-water are two commonly used methods for the extraction of plant metabolites which was used to extract the metabolites of wax apple,GC-TOF-MS technology was used to analyze the metabolites of wax apple,to study from the perspective of metabolomics changes after storage at low temperature for postharvest wax apple,as well as to find physical quality-related marker metabolites and metabolic pathways of this fruit to explore the mechanism of exogenous NO treatment on the physiological quality of the postharvest wax apple.The results of this study are as follows:1.In this study,we treated with the concentration of 10 and 0 μl/L(Control)NO on the postharvest wax apple.The effects of different concentrations of NO on the weight loss rate,hardness,cottony softening index,soluble solid content,and total sugar content were studied.The results showed that the fruit weight loss rate and cottony softening index increased gradually during postharvest storage,and the fruit hardness gradually decreased.The total sugar and soluble solids content increased first and then decreased.NO treatment can inhibit the increase of fruit weight loss rate and cottony softening index,slow down the decrease of soluble solids content and total sugar content,inhibit fruit physiological quality deterioration and delay fruit ripening and aging.2.The effect of 10 μl/L NO treatment on the sugar metabolism of postharvest wax apple is studied.The results showed that the content of glucose and fructose increased first and then decreased,and the content of sucrose gradually decreased.The content of sucrose was lower than that of glucose and fructose.Among Sucrose-metabolizing enzymes,the increased enzyme activities of AI,NI and SS in the decomposition could promote the disintegration of sugar,accelerate the aging of the wax apple.NO treatment can inhibit the activity of AI,NI,and SS in the disintegration direction of wax apple,slow down the transformation of sucrose in the fruit,increase the enzyme activity in the synthesis of SPS and SS,promote the synthesis of sucrose,and slow the senescence process of wax apple.3.The effect of methanol-water extraction and methanol-chloroform-water extraction on the metabolomics study of wax apple was compared.The results showed that methanol-water is more suiTab.for the extraction of wax apple metabolites.GC-TOF-MS technology was used to detect the metabolites of the wax apple in the NO treatment group and the control group at the 0,4th,8th,and 12th day of storage,and to study the metabolites changes,screening for differential metabolites,looking for metabolites and metabolic pathways related to maturation and senescence of wax apple during the maturation and senescence of the wax apple.The results indicated that metabolites in the control group during the storage process speculated that 52 metabolites with significant differences were identified,and 26 were identified in NO-treated groups.Compared with the storage day in NO-treated and control groups,40 different metabolites were found.This shows that NO treatment can reduce the change of metabolites during the storage of wax apple.There were 24 metabolic pathways enriched in metabolic pathways analysis of differential metabolites,in which arginine and proline metabolism,glyoxylate and dicarboxylate metabolism,citrate cycle(TCA cycle)metabolic enrichment were significantly higher.14 differential metabolites,such as citric acid,proline,N-acetyl-glumate,glycine,xylose,glucose,leucine,urea,methionine,stearic acid,xanthosine,etc.,involved in metabolic pathways are the key metabolites related to the deterioration of fruit quality of wax apple after harvest. |
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