The production of monoterpenes in both types of calli even exceeded
that found in the YP and VS aroma (Figs. 2 and 3). In particular,
the typical basil monoterpenes, such as limonene (13% DO;
15% RR) reached very high levels in the callus samples, while
1,8-cineole (21% DO; 16% RR) reached values simulating the aroma
of YP plants (Tables 2 and 3). On the other hand, the production of
phenylpropanoids in DO and RR calli was drastically reduced (0.9%
and 2%, respectively) in comparison with the in vivo and in vitro
plants YP and VS (Fig. 3). In particular, very low levels of methyleugenol
(0.4 ± 0.18%, DO; tr, RR) and eugenol (tr, DO; tr, RR) were produced
in the callus of both red-leaf cultivars (Table 3).