Effects of GA3 and TDZ combination on bitter and astringent taste compounds of Vitis vinifera×V. labrusca

ObjectiveThe experiment was conducted to explore the effect of gibberellin(GA3)and thidiazuron(TDZ) on physicochemical parameters and the bitter and astringent taste compound contents of Vitis vinifera×V. labrusca to pro-vide references for the reasonable use of plant growth regulators for fruit preservation and expansion.MethodThe be-rries of V. vinifera×V. labrusca were dipped with 25.0 mg/L GA3+2.5 mg/L TDZ during the beginning of the physiological fruit drop period and fruit enlargement stage respectively. The basic physiological indexes and the bitter and astringent taste compound content at different development periods were measured and analyzed.ResultCompared with control treatment,25.0 mg/L GA3+2.5 mg/L TDZ dipping could significantly improve the single berry weight,vertical diameter and transverse diameter of grape,significantly reduced soluble solids content in fruit at mature period(P<0.05,the same below),inhibited the degradation of chlorophyll and carotenoids to restrain the coloration of pericarp and promoted accu-mulation of the bitter and astringent taste compound contents(soluble tannin,flavonoid and total phenol)in fruits. Corre-lation analysis results showed that the bitter and astringent taste compound contents were significantly negatively correla-ted to soluble solids content and coloring index. And the bitter and astringent taste compound contents were significantly positively correlated to chlorophyll and carotenoids contents.ConclusionUniformly dipping the berries with 25.0 mg/L GA3+2.5 mg/L TDZ mixed aqueous solution at the early stage of physiological fruit dropping and the early stage of fruit enlargement stage can increase the yield and size of V. vinifera×V. labrusca,but slow down the degradation of chlorophyll and carotenoids which inhibits the fruit coloring and promotes the accumulation of bitter and astringent taste compound contents to some extent. Therefore,the dipped treatment is bad for fruit quality improvement.