Influence Of Foliar Sprayed Potassium Dihydrogen Phosphate And Calcium On Fruit Flavor Quality Of Cabernet Sauvignon(Vitis Vinifera)

Phosphorus,potassium and calcium are essential nutrients for plant growth and development.Many researches focus on the potassium dihydrogen phosphate effect for plant physiology,fruit sugar and acid content,but there are few studies on wine grapes flavor substances.Foliar spraying potassium dihydrogen phosphate is a common fertilization method.Calcium ion is an important intracellular "second messenger",it can regulate the plants physiological and biochemical processes through various ways.Many studies mainly concentrate on the fruit hardness and storage,and the research on the wine grapes flavor substances is also rare.This topic is aimed at the problem of wine grape poor coloring and lack flavor in Jinzhongnan area.In order to study the effects of potassium dihydrogen phosphate on anthocyanins,aroma compounds and the anthocyanin-related genes expression in Cabernet Sauvignon,and the effects of EDTA-Ca on flavonoids and aroma compounds,we studied the effects of three concentrations of potassium dihydrogen phosphate(1.0 g/L,3.0 g/L and 5.0 g/L)and 0.7 g/L EDTA-Ca at three spraying periods(1-2 week before veraison,latest phase of veraison and middle phase of maturation)respectively.The aim is to clarify the effects of potassium dihydrogen phosphate and calcium on the wine grape flavor,and lay a foundation for the application of potassium dihydrogen phosphate and calcium in wine grapes.The main findings are as follows:(1)The treatment sprayed 3.0 g/L potassium dihydrogen phosphate at the latest phase of veraison could improve the fruit quality.There was a difference in contents of soluble solids and flavanols in 2017 and 2018.The concentration of total phenol,total anthocyanin and tannin in fruits increased significantly in the treatment sprayed potassium dihydrogen phosphate at latest phase of veraison.Anthocyanins analysis showed the potassium dihydrogen phosphate treatment at the latest phase of veraison increased the anthocyanin content by 29.7%(2017)and 17.15%(2018),especially 3’5’-hydroxyl substitution,methylation and acylation anthocyanins.The potassium dihydrogen phosphate treatment at the latest phase of veraison affect the flavonols accumulation,and the concentration increased by 48.1% in 2017.Potassium dihydrogen phosphate treatment increased the aroma content by 7-10% in 2017,and the treatment sprayed at latest phase of veraison increased the fruit aroma by 2.5% in 2018.(2)Spraying potassium dihydrogen phosphate promoted some genes expression in the flavonoid synthesis pathway.Especially the treatment at the latest phase of veraison,the key genes up-regulated expression of Vvi CHS3,Vvi DFR,Vvi OMT,Vvi F3H2,Vvi LDOX and Vvi UFGT promoted the anthocyanins accumulation in the late stage of fruit ripening,which was consistent with the higher anthocyanin content of mature grape.(3)EDTA-Ca had less effect on the fruit sugar,anthocyanin and flavonols,while the flavanols content in treatment sprayed EDTA-Ca before veraison in 2017 increased by 21%,and all EDTA-Ca treatments increased the flavanols content by 87%-139% in 2018.EDTA-Ca treatment increased the aroma compoundsc ontent.Compared with the control,the higher alcohols content was 2.5 times and 2.7 times in the treatment sprayed EDTA-Ca at the phase before veraison.EDTA-Ca treatment at the latest phase of veraison significantly increased the higher alcohols content,and the increases of two years were 46% and 33%.The effects of EDTA-Ca treatment at the middle phase of maturation on aroma substances were different in 2017 and 2018.