灌水量对限根栽培‘阳光玫瑰’葡萄果实发育与香气物质积累的影响

Effects of Irrigation Amount on Berry Development and Aroma Components Accumulation of Shine Muscat Grape in Root-Restricted Cultivation

【目的】通过分析不同灌水量处理对葡萄果实品质指标、香气组分积累、香气物质合成相关基因表达影响的差异,确定灌水模式与鲜食葡萄感官品质形成间的关系,为限根栽培葡萄最佳灌水量的确定提供参考。【方法】以鲜食葡萄‘阳光玫瑰’为试材,设置对照组CK、轻度水分亏缺组(DI-1)、重度水分亏缺组(DI-2),系统比较不同灌水量对葡萄果实外观形态指标、色泽指标、香气组分、萜烯合成相关基因表达水平等的影响。【结果】灌水量影响葡萄果粒的形态与质地特征,采收期时葡萄果粒的纵径并未受到灌水量的显著影响,而亏缺灌溉组果粒的横径、单粒重显著降低(P<0.05)。葡萄果肉的硬度也受到亏缺灌溉的影响而下降,特别是DI-2组,葡萄果肉硬度明显低于其他处理组。亏缺灌溉组DI-1、DI-2的葡萄果实中葡萄糖含量显著高于对照处理,重度亏缺组DI-2果糖含量显著高于其他处理,而轻度的亏缺灌溉(DI-1)并未对葡萄果实的可溶性固形物、可滴定酸含量产生显著影响。亏缺灌溉处理下葡萄果皮中叶绿素、类胡萝卜素含量均出现降低,DI-2组果皮中叶绿素与类胡萝卜素含量的比值最低。灌水量影响到葡萄果实中香气组分的积累,对于萜烯类物质,轻度亏缺灌溉DI-1处理的果实中柠檬烯、水芹烯、α-蒎烯、γ-松油烯、(E)-β-罗勒烯、萜品油烯、(E)-呋喃氧化芳樟醇、芳樟醇、二氢芳樟醇、α-萜品醇、香茅醇、橙花醇、香叶醇等组分的含量最高,DI-1处理的果实中萜烯类物质总量也最高,DI-2组中萜烯类物质含量次之,而对照组最低。由酯类物质总量来看,DI-1组中酯类物质含量最高,对照组次之,而DI-2组含量最低;由醛类物质总量来看,轻度亏缺灌溉组DI-1中醛类物质明显低于照组与DI-2组;由高级醇类物质总量来看,DI-1组含量最高,DI-2组含量次之,对照组含量最低。不同灌水量条件下萜烯合成相关基因的响应程度与表达趋势存在差异,VvDXS1、VvDXS2、VvDXR、VvDHR、VvPNLinNer1、VvCSLinNer、VvGwbOci、VvCSbOci、VvGwGer等基因均能响应水分亏缺而上调。【结论】综合果实中香气组分的积累量与感官品质,轻度水分亏缺(60%-70%田间最大持水量)更能促进‘阳光玫瑰’葡萄果实香气品质的形成,有助于提高果实的商品价值。

【Objective】The effects of different irrigation amounts on grape berry quality, aroma component accumulation, and the expression level of aroma compounds biosynthetic genes were studied to determine the relationship between irrigation patterns and sensory quality of table grapes, so as to provide a reference for choosing the optimal irrigation amount in root-restricted cultivation.【Method】The table grape cultivar Shine Muscat was used as the test material, the control group(CK), the mild water deficit group(DI-1), and the severe water deficit group(DI-2) were set up to systematically compare the effect of different irrigation amounts on the morphological indicators, appearance color indicators, aroma components, and expression levels of terpene biosynthetic genes of grape berries. 【Result】Irrigation amount could affect the morphological and texture characteristics of grape berries. Comparing with other treatments, the longitudinal diameter of grape berries at harvest time was not significantly affected by irrigation amount, while the horizontal diameter and single berry weight of grape berries in deficit irrigation group were significantly reduced. The firmness of grape pulp also decreased under the influence of deficit irrigation, especially under DI-2 group, of which the pulp firmness was significantly lower than that under other treatment groups. Meanwhile, the glucose content in the grape berries under the deficit irrigation group DI-1 and DI-2 was significantly higher than that under the control treatment, and the fructose content under the severe deficit irrigation group DI-2 was significantly higher than that under other treatments. Mild deficit irrigation of DI-1 exerted little effect on the content of total soluble solids and titratable acid in grape berries. The contents of chlorophyll and carotenoids in grape skins were decreased under the deficit irrigation treatment, and the ratio of the chlorophyll content to carotenoids content in the skins of the DI-2 group was the lowest. Additionally, the amount of irrigation also affected the accumulation of aroma components in grape berries. The terpenes compounds reached the highest content in the berries of the DI-1 group, such as limonene, phellandrene,α-pinene, γ-terpinene,(E)-β-ocimene, terpinolene,(E)-furanoxylinalool, linalool, dihydrolinalool, α-terpineol, citronellol, nerol, and geraniol, followed by the content of terpenes under the DI-2 group, and the lowest under the control group. As for esters, the total content of those compounds under the DI-1 group was the highest, followed by the control group, and the content of the DI-2 group was the lowest. For the total amount of aldehydes, the content in the DI-1 group were significantly lower than those in the control group and DI-2 group. For the total amount of higher alcohols, the content of DI-1 group was the highest, followed by DI-2 group,and the control group was the lowest. There were differences in the expression patterns of terpene biosynthesis-related genes under different irrigation conditions. The expression of VvDXS1, VvDXS2, VvDXR, VvDHR, VvPNLinNer1, VvCSLinNer, VvGwbOci,VvCSbOci and Vv Gw Ger were up-regulated in response to water deficit.【Conclusion】According to the accumulation of aroma components and the comprehensive score of sensory quality, the mild water deficit(60%-70% of the maximum water holding capacity in the field) could better promote the formation of aroma quality of Shine Muscat grape berries and improve their commercial value.