Effects Of 2,4-D On The Contents Of Sugars,Acids,Total Polyphenol And Flavonoids In Navel Orange During Storage

2,4-D(2,4-Dichlorophenoxyacetic acid,2,4-dichlorophenoxyacetic acid)is a highly effective citrus fruit postharvest preservative,but its safety is controversial.Understanding its mechanism of action can be safe and efficient.Alternatives provide the basis.In order to further clarify the key metabolites regulated by 2,4-D,as well as the key period of action and the tissue of the fruit,this study used 'Newhall' navel orange as the test material and detected 200mg/L 2,4 by HPLC.Changes in 14 primary metabolites in the total peel,flesh,yellow skin and white cortex of the treated fruit after-D treatment,including 3 soluble sugars(fructose,glucose and sucrose)and 11 organic acids(Citric acid,oxalic acid,tartaric acid,quinic acid,malic acid,aconitic acid,lactic acid,ascorbic acid,acetic acid,succinic acid,fumaric acid);at the same time,four skin peels,pulp,yellow skin layer and white skin layer were determined by microplate reader.The content of total phenol and total flavonoids in the tissue.The results are as follows:Effects of 1.2,4-D treatment on fructose,glucose and sucrose in various tissues(total peel,yellow skin layer,white cortex and pulp)of 'Newhall' navel orange during storage: 1).Within 84 days of storage,total The contents of glucose,fructose and sucrose in the peel decreased.The content of fructose in the total peel was significantly higher than that in the control from 7d to 56 d after 2,4-D treatment.The difference of glucose and sucrose was not significant.The fluctuation of glucose,fructose and sucrose in the pulp was slightly different.The content of three sugars in the treatment group was higher than that in the control at 3d~42d and 84 d after 2,4-D treatment.The contents of glucose,fructose and sucrose in the white cortex decreased,and the treatment group was 3d~84d after 2,4-D treatment.Sucrose content was higher than the control group.2).Compared with before treatment,the total amount of yellow skin layer,white skin layer and pulp sugar after 2,4-D treatment was 13.7%,8.2% and 45.8% higher than that of the control group,and the effect was not obvious in the total peel.Effects of 2.2,4-D treatment on the acid components of various tissues(total peel,yellow skin layer,white cortex,pulp)during postharvest storage of 'Newhall' navel orange fruit: 1).4 tissues(total peel,yellow)The content of citric acid in cortex,white cortex and pulp was the highest.The order of citric acid content among the four tissues was: total peel,pulp> yellow skin layer and white skin layer,accounting for 62.7%,58.35%,48.2% and 38.59% of the total..2)After treatment with 2,4-D,the organic acid content of each tissue was adjusted to varying degrees.The acid content in the pulp increased from 14 d to 42 d after 2,4-D treatment;the content of citric acid,tartaric acid,oxalic acid and lactic acid in the total peel increased in 2,4-D treatment for 3d~56d;white cortex tartaric acid and quinine The acid content in the 2,4-D treatment was significantly higher than that in the control at 7d~84d.The content of citric acid,malic acid,lactic acid,fumaric acid and succinic acid in the yellow skin layer was higher than that in the control at 2,4-D for 7d~42d,and the ascorbic acid content was higher.The treatment was higher than the control at 7d~84d.The effects of 3.2,4-D treatment on the content of phenolic substances in various tissues(total peel,yellow skin layer,white cortex and pulp)of 'Newhall' navel orange during postharvest storage: 1).Total phenolic content of total pericarp during storage for 84 days The total phenolic content of white cortex and yellow skin layer increased first and then decreased,and the total phenolic content of flesh fluctuated.The effect of 2,4-D treatment on total phenolic content in four tissues was not significant,but there was significant difference in total phenolic content between tissues.The total phenolic content in the pericarp tissue was significantly higher than that in the pulp;and the total phenolic content in the white cortex was the highest,which was about 6.23 times of the total phenolic content of the pulp.2).2,4-D treatment has a significant effect on total flavonoid content.The total flavonoid content of total peel after 2,4-D treatment was significantly higher than that of the control group at 3d~84d,and the effect was not significant in other tissues.The flavonoid content of the total peel and yellow skin layer of the treated group increased.Compared with the tissue,the content of flavonoids in the peel was about 3.47 times of the content of flavones in the flesh;while the content of flavonoids in the peel was the highest in the peel,which was 3.55 times that of the white cortex and 7.10 times that of the flesh.In summary,2,4-D treatment can delay the sugar degradation rate by increasing the soluble sugar content of the pulp.The 2,4-D treatment can induce the synthesis of organic acid content in the four tissues,delaying the degradation,and the peel is treated for 7d~ 42 d,the effect was the most obvious,and the effect of pulp on the 14 th to 42 d after 2,4-D treatment was obvious.2,4-D had significant effects on the total flavonoids content of the peel,and had little effect on the total phenolic content of the fruit tissues.