Effects Of Exogenous ABA With Different Concentrations On Grape Fruit Quality And Its Mechanism

In order to explore the influence of exogenous shedding acid（ABA）on grape fruit quality and its control mechanism,With‘Jumeigui’and‘Summer black’as the test materials,At the beginning of the transition,100 mg L^-1ABA+0.05%（v/v）Tween 20（T1）,500 mg L^-1ABA+0.05%（v/v）Tween 20（T2）,1000 mg L^-1ABA+0.05%（v/v）tween 20（T3）ABA,Control spray with water+0.05%（v/v）Tween 20,The quality of the fruit and the sucrose metabolic-related enzyme activity and genes expression were measured regularly.The following main test results are obtained:1.ABA improves the grape fruit quality.ABA treatment reduces the ripening period of the‘Summer black’fruit,making the‘Summer black’fruit mature about14d early,making it early listing.However,the ABA treatment reduces the‘Summer black’fruit volume,single grain weight and cross diameter,increases the soluble sugar content and the soluble solid（TSS）content,and reduces the titrate acid（TA）content.ABA treatment failed to mature the‘Jumeigui’early,but increases the size of the fruit,single weight and fresh weight.Improve the soluble sugar content and TSS content of the fruit,and reduce the TA content.In appearance,ABA treatment promotes fruit coloring and colorside accumulation,which works best with T3,T2secondary.‘Summer black’and T3 content were 4.56 mg g^-1and 3.59 mg g^-1.2.ABA treatment makes the grape fruit peel thickening,facilitate fruit transportation and storage.The number of epidermal layers of ABA treated‘Summer black’and‘Jumeigui’peel remained unchanged,but the thickness and cross section of the epidermal layer increased;the number,thickness and cross section of the subepidermal cells increased significantly,with T3 treating the thickest peel.3.ABA increases the sucrose metabolic enzyme activity in the grape fruit.After exogenous ABA treatment,glucose and fructose content increases in the‘Summer black’and‘Jumeigui’fruit,ABA treatment increases acid converting ase（AI）,neutral invertase（NI）,sucrose synthase（SS decomposition direction）,sucrose phosphate synthase（SPS）activity,so ABA processing promotes fruit sugar accumulation through enzyme activity associated with sugar metabolism.4.The results of the transcription group of grape fruits were as follows:582,560,1446 different expression genes（DEGs）in 3 sampling points.A total of 20different genes related to fruit sugar transport and metabolism were selected for KEGG function enrichment.After RT-q PCR verified 12 differential expression genes,the expression trend of DEGs relative expression levels was similar to the transcriptional data.ABA treatment promotes glucose transport and the expression of metabolism-related genes.