Okra(hibiscus Esculentus L.)fruit Quality Analysis And The Response Of Cellulose Content To Exogenous Hormone

Okra（Hibiscus esculentus L.）is an annual herbaceous plant in the genus Okra of the Malvaceae family.Because of its high nutritional and medicinal value,it has attracted more and more attention from people.It has also transformed okra from a traditional vegetable to a new type of green nutrition and health-care functional vegetable,and the cultivation area in China is also constantly expanding.The main edible organ of okra is the fruit,and the freshness period of the tender pod is relatively short.The fruit becomes fibrotic from about 10 days after flowering and loses its edibility.At present,there were few systematic research reports on the quality and aging of okra fruit.To this end,this experiment selected 4 widely cultivated okra varieties（Taiwan Wufu,Japanese Super Five-star,Kariba,Yang Guifei）.The contents of soluble sugar,soluble protein,vitamins,soluble solids,cellulose and flavonoids in okra fruit during the quality formation period of 5-10 days after flowering were measured and its quality was evaluated.Furthermore,the main factors of the aging of okra fruit,i.e.,the relationship between cellulose and exogenous hormones were mainly discussed.The assay results are as follows:（1）The contents of soluble sugar and soluble protein in four okra varieties were determined,it was found that both contents gradually decreased with the increase of days after flowering.Soluble sugar decreased faster at 5-8 days after flowering,slowed down at 8-10 days after flowering,soluble protein slowed at 5-7 days after flowering,and faster at 7-10 days after flowering.（2）The contents of vitamin C and flavonoids of okra fruit showed the trend of increasing first and then decreasing with the increase of days after flowering,additionally,highest at 6-7 days after flowering among the varieties.（3）The cellulose contents of four okra varieties during fruit development were measured.Results indicated that the cellulose contents of the fruit increased with days after flowering.It was Yang Guifei has the highest cellulose contenst at 10 days after flowering.（4）The contents of soluble sugar,soluble protein,vitamin C,flavonoids,and cellulose in okra fruits were used as the evaluation index.The membership function method was used to conduct a preliminary evaluation of four okra varieties fruit quality.Results suggested that the highest was Japanese Super Five-star and the lowest was Yang Guifei,so the best nutritional quality was Japanese Super Five-star,followed by Kariba,and finally Yang Guifei.（5）Four okra varieties were treated with hormones（gibberellin,abscisic acid,auxin,brassinolide）,and changes of cellulose contents in okra fruit after treatment were measured.It was found that the treatment of gibberellin and brassinolide to reduce the cellulose content of okra fruit was better.According to the results of quality analysis,treatment of okra fruit with 100μmol·L^-1gibberellin for 3 consecutive days on the fourth day after anthesis can effectively extend the fresh eating period of okra fruit.（6）Using q RT-PCR to analyze the effect of hormones treatment on the gene expression related to the regulation of okra cellulose accumulation in Japanese Super Five-star,it was found that after exogenous spraying of three hormones,gibberellin,abscisic acid and brassinolide,the expression level of the cellulose synthase gene He Cesa7 was lower than that of the control,while the expression levels of the endoglucan gene He EG6 and the transcription factor He MYB46 were not significantly different from those of the control group.Therefore,it was speculated that these three hormones reduced the cellulose accumulation in okra fruit by reducing the expression of cellulose synthase gene He Cesa7.