## 3 Results and Discussion
### Influence of the Foliar MeI and ACP-MeI Treatments on Must Volatile Compounds  
Figures 1-3 and Table 2 show the results of must volatile primary aroma content in control and in samples from treated grapevines with methyl jasmonate (MeJ) and with nanoparticles doped with MeJ (ACP-MeI), in 2019 and 2020 seasons. A total of 37 compounds were identified and semi-quantified, including terpenoids, C\({}_{13}\) norisoprenoids, benzenoid compounds, alcohols, carbonyl compounds, C6 compounds, and other compounds. Figure 1 shows the concentration of terpenoids found in the control samples and in the grapes from the treatments with MeJ and ACP-MeJ, in 2019 and 2020 seasons. In 2019, limonene (Figure 1a), geraniol (Figure 1e), and geranyl acetone (Figure 1g) decreased their concentration in ACP-MeJ grapes relative to control and MeJ grapes. This effect had already been observed in _Vitis vinifera_ L. cv. Tempranillo variety after the application of MeJ [34]. The MeJ-based treatment showed no significant differences with the control for these compounds. For the same year, p-cymene (Figure 1b), linalool (Figure 1c), and \(\alpha\)-terpineol (Figure 1d), which are very important terpenoids for grape and wine aroma [36], increased their content in MeJ grapes, and decreased it in ACP-MeJ samples with respect to control one. In the case of geranic acid (Figure 1f), both treatments significantly decreased the amount of this compound. Finally, in the same year, total terpenoid concentration (Figure 1h) increased in grapes from the foliar application of MeJ, and decreased in grapes treated with ACP-MeJ with respect to control grapes. In 2020, limonene and p-cymene (Figure 1a,b) increased their concentration in MeJ grapes relative to control grapes. This effect had already been observed in _Vitis vinifera_ 'Garnacha' variety after the application of MeJ [12]. The MeJ-doped nanoparticles treatment showed no significant differences in those compounds with the control samples. In the  
Figure 2: C\({}_{13}\) norisoprenoids concentration (\(\mu\)g/L) in grapes from control, methyl jasmonate (MeJ) and nanoparticles doped with MeJ (ACP-MeJ) foliar treatments, in 2019 and 2020 seasons. All parameters listed with their standard deviation (\(n=3\)). For each season and compound, different letters indicate significant differences between samples (\(p\leq 0.05\)). TDN: 1,1,6-trimethyl-1,2-dihydronaphthalene. [PERSON] et al., 2018 [34] study, it is shown that the synthesis of p-cymene increases upon application of MeJ. Moreover, for the same year, linalool (Figure 1c), geranic acid (Figure 1f) and geranyl acetone (Figure 1g), significantly increased their concentration in MeJ-treated and ACP-MeJ-treated samples with respect to the control. In the case of \(\alpha\)-terpineol (Figure 1d), both foliar treatments increased the content of this compound in the grapes, with ACP-MeJ increasing to a greater extent. Regarding geraniol (Figure 1e), only the ACP-MeJ treatment significantly increased the amount of this compound with respect to the control grapes, despite being a treatment with a concentration 10 times lower. In this season, the total concentration of terpenoids (Figure 1h) increased significantly with both treatments with respect to the control grapes, being more effective the application with MeJ. The increase in the amount of terpenoids after foliar application with MeJ has been previously demonstrated by other groups [5; 12; 37]. However, some studies have also found that the content of total terpenoids decreases when MeJ is applied [34; 38]. In general, the treatments increased the amount of several terpenoids found in the grapes (Figure 1). This may be due to the foliar treatments were applied during veraison, moment when free terpenids start to be produced [12; 39].