## 3 Results
### Effects of Rootstocks on Volatile Compound Profiles in Berries and in Wines  
A total of 60 volatile compounds were quantified across three graft combinations and own-rooted CS berries (Supplemental Materials Table S6). These aroma substances were categorized into the following: C6/C9 compounds, terpen, higher alcohols, benzenes, acids, esters, C\({}_{13}\)-norisoprenoids, volatile phenolic, and others. To better understand how the aroma compounds in the grape berries relate to the wine, we would look at the total amount of aroma substances in the berries, which included both free-form and bound-form aroma compounds, in the next analysis. As shown in Figure 2A, the C6/C9 compounds were the most abundant in the grapes. 1103P tended to increase the C6/C9 substance concentration and showed a significantly higher level than CS and other graft combinations in 2020. Furthermore, CS/5A and CS/SO\({}_{4}\) showed no significant difference in C6/C9 substance concentration in 2018 and 2019 compared to CS but significantly reduced it in 2020. Also, 1103P and SO\({}_{4}\) did not significantly affect the levels of C\({}_{13}\)-norisoprenoids in the berries over the three years, while 5A only lowered the levels of C\({}_{13}\)-norisoprenoids in the berries in 2020 (Figure 2D). 5A and SO\({}_{4}\) lowered the amounts of terpen in berries in 2018 and 2020, while 1103P seemed to lower the amounts of terpen in 2020. For the concentrations of benzenes and acidic compounds, the different graft combinations did not show differences in 2019, and SO\({}_{4}\) tended to reduce both types of substances in 2020 (Figure 2E,F). For higher alcohols, different graft combinations did not show differences in 2020, and 5A had a tendency to increase the concentration of higher alcohols in 2019  
Figure 1: Meteorological data of Beijing in 2018–2020 (**A–C**). Texture of vineyard soil (**D**). note: pink sqaure represents the grape berries at veraison; BJ stands for the abbreviation of the experimental site, Beijing. (Figure 2B). Volatile phenolic compounds, which could contribute to irritating flavors such as smoky, spicy, animal, medicinal, and chemical notes, are less abundant in the berries and primarily consist of guaiacol and phenol (Figure 2G). In this study, the different graft combinations were similar to CS in 2018 and 2019, but in 2020, 1103P and SO4 significantly raised the levels of volatile phenolics, while 5A significantly lowered them. In addition, a total of 75 aroma compounds were detected in the wines of three graft combinations and CS in two vintages (Table S7). These aroma compounds could also be classified into C6/C9 compounds, terpenoids, higher alcohols, benzenes, acids, esters, C13-norisoprenoids, and volatile phenolic compounds. Higher alcohols and esters were the main compounds in wine. Three rootstocks significantly reduced the concentration of higher alcohols in 2020. In this study, SO4 was found to significantly reduce the content of higher alcohols in the wines in 2020, which showed a consistent effect of SO4 on the content of higher alcohols in the wines (Figure 3B). Interestingly, 1103P and SO4 significantly reduced the concentration of esters in wines in 2019, while only showing a trend of reduction in 2020 (Figure 3H). 1103P reduced the concentration of benzene substances in wine, while increasing the concentration of C6/C9 alcohols. 5A and SO4 only had a trend to reduce benzene compounds in 2020 (Figure 3G). All three rootstocks significantly reduced the concentration of volatile phenolics in wine (Figure 3F). 5A and 1103P had a tendency to reduce terpen in wine, while SO4 significantly increased terpen in wine in 2019. In 2019, all three graft combinations had significantly lower terpene concentrations  
Figure 2: Aroma compound (C6/C9 compounds, higher alcohols, terpenes, C13-norisoprenoids, acids, benzenes, volatile phenolic, others, esters) concentrations of different grafted combinations of Cabernet Sauvignon in berries (**A–I**).