Effects Of Tree Shapes And Rootstock On Phenols And Volatile Substances In Cabernet Sauvignon

Grape berries contain a large number of polyphenols and volatile substances,which not only have important effects on grape quality and wine flavor,but also have certain health care effects.It was found that proper tree shape could improve photosynthesis,balance vegetative growth and reproductive growth of tree body,and improve fruit quality.Rootstock can regulate tree potential,enhance grape resistance,affect the absorption and transportation of nutrients,and improve the economic traits of varieties.In this study,cabernet sauvignon was used as the test material to elucidate the effects of tree shapes and rootstock on polyphenols and volatile aroma substances in berries,and to provide a theoretical basis for grape standardized cultivation.The main research results are as follows:(1)The contents of total phenols,total flavonoids and total flavane-3-ols were higher in ‘Modified VSP’(slope trunk with a vertical shoot positioning training system)berries,but the content of total flavanols was lower than that of F-MT(Fan training system with multiple trunks)berries.The contents of gallic acid,protocatechuic acid,p-hydroxybenzoic acid and syringic acid in the mature stage of M-VSP berries were significantly higher than that of F-MT,while the contents of catechin,epicatechin,epigallocatechin,epicatechingallate and p-coumaric acid were lower than that of F-MT.Under the two tree shapes,resveratrol and polydatin were abundant before the color turning stage(65 days after flowering),the content of M-VSP was low,and there was little difference in the ripening stage.(2)The content of total phenols in grafted seedlings was higher,the content of total flavonoids,total flavanols and total flavanol-3-ols were lower,the content of catechin,epicatechin,epigallocatechin,epicatechingallate and p-coumaric acid were higher than the self-root seedlings,the content of gallic acid,protocatechuic acid,p-hydroxybenzoic acid,syringic acid were significantly lower than the self-root seedlings,the content of resveratrol and polydatin are low in color turning stage(65 days after flowering).(3)There are 84 kinds of volatile aroma substances in Cabernet Sauvignon ripening berries,including alcohols,aldehydes,ketones,esters,acids and olefins.Among them,there are 61 types of F-MT and 49 types of M-VSP.The main volatile substances are alcohols and aldehydes.There are many types(18,13 types of M-VSP,23 and 15 types of F-MT).Its proportion is also large(M-VSP is 25.32%,30.97%,F-MT is 39.27%,31.73%).The highest volatile aroma substances in the two tree shapes are 2-octanol,followed by hexanal.The content of 2-octanol in F-MT is 6.12% higher than the M-VSP,and the content of hexanal is 5.35% higher.(4)There are 75 kinds of volatile aroma substances in Cabernet Sauvignon ripening berries,including alcohols,aldehydes,ketones,esters,acids and olefins.Among them,there are 49 types of self-root seedlings and 60 types of grafted seedlings,the main volatile substances were alcohols and aldehydes.Among the self-root seedlings,alcohols were the most variety(18 kinds),and aldehydes were the largest percentage(30.97%).The aldehydes in the grafted seedlings were not only of many kinds(17kinds),but also of large proportion(31.02%).The volatile substance with the highest content in self-root seedlings was sec-octanol(21.11%),in grafted seedlings was hexaldehyde(25.85%).The content of sec-octanol and hexanaldehyde in grafted seedlings was 1.78% and 5.17% higher than that in self-rooted seedlings.