不同水分调亏处理对葡萄果皮酚类物质的影响

Effects of different regulated deficit irrigation treatments on phenols in grape berries

【目的】探究2种不同水分调亏处理方式对葡萄果皮酚类物质的影响。【方法】以寒香蜜和紫甜无核2个葡萄品种为试验材料,采用滴灌控水,设置正常水分(CK)、浇水量减半(T1)及浇水次数减半(T2)3个处理,测定各处理的可溶性固形物、总酚、总花色苷及各酚类物质含量变化。【结果】T1与T2处理均能增加寒香蜜和紫甜无核葡萄果皮中酚类物质含量,提高果实品质。寒香蜜葡萄果实中,T2处理的可溶性固形物含量更高,与T1处理相比,T2处理更能促进果皮中酚类物质的积累。而紫甜无核葡萄果实中,T2处理的可溶性固形物含量高于T1,与T2处理相比,T1处理更有助于葡萄果皮中低聚黄烷醇、酚酸及芪类物质含量的增加。【结论】寒香蜜葡萄应采用T2处理提高果实品质,T1处理更适用于紫甜无核葡萄提高果实品质。

【Objective】Regulated deficit irrigation treatments have significant effects on the content of phenolic metabolites in the peels of grape(Vitis vinifera L.)berries.Studying the effects of various regulated deficit irrigation treatments on the metabolism of phenolic substances in grape berry peels can not only provide reference for improvement of grape berries quality,but also provide methods to save water and thereby improve the economic benefits.【Methods】Three-year-old ridge-rooted Reliance(Vitis labrusca L.×V.vinifera L.)and Zitian Seedless(V.vinifera L.)were selected as the materials.The same pruning and fertilization regimes were applied to all grapevines.Regulated deficit irrigation treatments included 2.5 L irrigation every 4 days(T1)and 5 L every 8 days(T2)from prior to veraison till full berry maturity,and irrigation with 5L every 4 days was set as the control.At ripe stage,berries with uniform maturity and no mechanical damage were collected for quality analysis.Total soluble solids(TSS)were measured using a PAL-1 refractometer.Total phenol was determined by Folin-Phenol reagent.Total anthocyanins were measured using an ultraviolet spectrophotometer.The skin was separated from the pulp and both tissues were immediately frozen in liquid nitrogen,and stored at -80℃ for further use.Phenolic metabolites of the grape skins were measured by high performance liquid chromatography-mass spectrometry(HPLC-MS).【Results】The results showed that T1 and T2 treatments increased TSS and total phenol content in Zitian Seedless grape,and total anthocyanins and most phenolic metab olites in the both cultivars.Seventeen anthocyanins,twenty flavonols,sixteen flavanols,three other flavonoids,fifteen phenolic acids and four stilbenes were detected in our study.In Reliance berries,the contents of TSS and total phenol in T2 was significantly higher than in T1.Compared with the control in Zitian Seedless,the contents of TSS and total phenol increased significantly in the groups of the two regulated deficit irrigation treatments and there was no significant difference between T1 and T2.In T2,cyanidin and delphinidin were significantly increased in Reliance peels,and their concentrations were higher than in T1.The contents of methylated anthocyanin(peonidin,petunidin and malvidin)were significantly higher in T1 than in T2,but the contents of anthocyanins without glycosides were higher in T2.We also found that T1 significantly increased the contents of cyanidin and peonidin in Zitian Seedless,and T2 significantly increased the contents of tri-substituted anthocyanins(delphinidin and malvidin).Flavonol metabolites in the two cultivars mostly existed in the form of flavonol glycosides.In Reliance berries,the contents of all flavonol metabolites but quercetin in T2 were significantly higher than in T1.However,in Zitian Seedless berries,the flavonol metabolites in T1 exceeded that in the other two groups.Among the flavonol metabolites,the myricetin and kaempferol conjugates were higher in T1 than in T2,but isorhamnetin-3-rutinoside,rutin,quercetin-3-glucuronide and quercetrin contents were the opposite.For flavanols,water stress could significantly increase their contents in both cultivars.However,in Reliance berries,the contents of flavanols in T2 were significantly higher than in T1,but there was an opposite trend of increased flavanols under the two treatments in Zitian Seedless berries.In both cultivars,except for proanthocyanidin-B2,most flavan-3-ols and their polymers were significantly higher in T1 compared with T2.Dihydroquercetin,phloridzin and luteolin were detected in both cultivars.Among them,the contents of dihydroquercetin and phloridzin increased,while that of luteolin decreased under T1 and T2.In Reliance berries,the contents of 2,5-dihydroxybenzoic acid,cis-caftaric acid,ellagic acid,p-coutaric acid,chlorogenic acid,caffeic acid,p-coumaric acid and 3,4-dihydroxybenzoic acid in T2 were significantly higher than in T1 and the control.In Zitian Seedless berries,the contents of 5-O-caffeoylquinic acid,cis-caftaric acid,caffeic acid and p-coumaric acid in T1 were significantly higher than in T2,while the contents of ellagic acid and syringic acid were in a opposite pattern.In addition,all the stilbenes were increased by the two regulated deficit irrigation treatments.【Conclusion】Moderate water stress applied from veraison can not only promote the accumulation of phenolic metabolites and thus improve the quality of grape berry,but also improve water utilization.