Study On The Effects Of GA₃ And CPPU On The Berry Growth And Quality Of ’Jingmi’ Table Grape

This research takes the table grape ’Jingmi’ was used as the research object.Using different concentration of GA₃ to dip the inflorescence at 9d,12d,15d before blooming;Using different concentrations of GA₃ or/combined with CPPU to dip the flowers/ears on 3d and 15d after full bloom,and using HPLC technology and RNA-seq technology to study the effect of plant growth regulators on the berry growth,inflorescence elongation and fruit quality formation of ’Jingmi’grapes berries.The results are as follows:1.Use different concentrations of GA₃ to treat inflorescences at different stages before blooming can lengthen the inflorescence to a certain extent.Among them,using 5mg/L GA₃ 15 days before the blooming has the most significant effect on inflorescence elongation,which can make the inflorescence elong by 71.57%.2.Treatments with different concentrations of GA₃ or/and CPPU at different stages after blooming have a regulatory effect on the growth and development of ’Jingmi’ grape berries.Among them,treatment T4（25mg/L GA₃+5mg/L CPPU,25mg/L GA₃+5mg/L CPPU）on the berry horizontal diameter,longitudinal diameter,and single berry quality increase the most significant,and the fruit shape index is reduced,the fruit tends to be round,and the appearance quality of the grape berry are significantly improved.3.Treatments with different concentrations of GA₃ or/and CPPU at 3 different stages after blooming can promote the improvement of the fruit quality of ’Jingmi’ grapes.Treatment T4（25mg/L GA₃+5mg/L CPPU,25mg/L GA₃+5mg/L CPPU）has the most significant effect on the contents of titratable acid,total phenols,vitamin C,sucrose and phenolic acids in the berry;Treatment of T5（25mg/L GA₃+5mg/L CPPU,25mg/L GA₃+10mg/L CPPU）has the most significant effect on the contents of soluble solids,soluble total sugars,reducing sugars,tannins,fructose,glucose,flavanols and flavonols in the berry.Among them,the highest content of soluble sugar is fructose,and the highest content of monomeric phenols is flavonols,which significantly improves the internal quality of the berry and promotes the accumulation of berry flavor substances.4.After blooming,the various treatments（T3,T4,T5,T8）after the combination of GA₃ and CPPU with different concentrations at different stages have significantly better control effects on the growth and quality of the’Jingmi’ grape berry than the individual treatments（T1,T2,T6,T7）.A comprehensive comparison found that the GA₃ concentration was 25 mg/L and the CPPU concentration was 3～5mg/L had the best control effect on berry growth;the GA₃ concentration was 25mg/L and the CPPU concentration was 5～10 mg/L,which had the best control effect on grape fruit quality.5.Transcriptome sequencing analysis was performed on the treatment T2 and CK berries of’Jingmi’ grapes at different stages of growth and development.Comparing each period of treatment（1T-vs-1C,2T-vs-2C,3T-vs-3C）,there are 2453,1885 and 680 significantly DEGs,which include the regulation of plant hormone synthesis and responding genes,transport proteins and key genes in signal pathways,etc.Changes in the expression patterns of extracellular region,plant-type cell wall,cell wall organization,and transporter gene timing suggest that cell wall relaxation may be the main cause of grape berries swelling.In addition,GA₃ and CPPU also participated in regulating the expression of flavonoid biosynthesis,starch and sucrose metabolism,and carotenoid biosynthesis genes in Jingmi’ grape berries,and ultimately improved the quality of grape berries.