外源单糖喷施对'赤霞珠'葡萄果实品质及酚类化合物的影响OA

To clarify the effects of exogenous monosaccharides on quality-related indices of'Cabernet Sauvignon'grapes,grape clusters were sprayed with 150 mmol/L fructose,glucose,and rhamnose at the early veraison stage,with sterile water spraying set as the control.Berry samples were collected at E-L35 to E-L39 according to the Eichhorn-Lorenz(E-L)phenological staging system,and quality indicators,including anthocyanin fractions,were determined,followed by principal component analysis(PCA)for comprehensive evaluation of the fruit quality and winemaking potential of the grape berries.The results showed that,compared with the control,all three exogenous monosaccharides increased 100-berry weight at the E-L38 stage and sugar content at the E-L36 stage,while reducing titratable acid and malic acid contents at the E-L38 stage.Among them,fructose treatment showed the most pronounced sugar-increasing effect,increasing by 15.66%relative to the control,whereas glucose treatment showed the most pronounced acid-reducing effect,reducing malic acid by 47.96%.Exogenous monosaccharides treatments also facilitated the accumulation of skin phenolics and anthocyanins at the E-L39 stage.Glucose treatment induced prominent increases in skin total phenols,total anthocyanins,and nine monomeric anthocyanins,including delphinidin-3-O-glucoside,petunidin-3-O-glucoside,and peonidin-3-O-glucoside,with increases of 10.8%,7.2%,and 26.69%-99.28%,respectively.Fructose treatment significantly elevated flavanol and flavonoid contents,whereas rhamnose treatment significantly raised the proportion of flavonoids and acylated anthocyanins.PCA revealed that the glucose treatment possessed the optimal comprehensive performance.Spraying exogenous monosaccharides at early veraison helps modulate sugar-acid composition and promote the accumulation of skin phenolics and anthocyanins in'Cabernet Sauvignon'grape,among which glucose showed the optimal effect and was beneficial to acid balance and color formation in wine.