Abstract
This work was carried out to establish adventitious root culture system in three Panax species (wild-grown P. ginseng, P. quinquefolium, and P. japonicum) to analyze their ginsenoside productivity. Adventitious roots were induced directly from segments of seedlings after cultured on MS(Murashige andSkoog 1962) solid medium containing 3.0 mg/l IBA. Omission of $NH_4NO_3$ from the medium greatly enhanced both the frequency of adventitious root formation and number of roots per explants in all the three Panax species. However, elongation of post-induced adventitious roots was enhanced on medium with $NH_4NO_3$. Two-step culture protocol: $NH_4NO_3$-free medium for first two weeks of culture, followed by $NH_4NO_3$ containing medium for further 4 weeks, greatly enhanced the fresh weight increase of adventitious roots in all the three ginseng species. The fresh weight of adventitious roots was high in P. quinquefolium and low in P. ginseng, followed by P. japonioum regardless of the composition of medium. Pattern and content of ginsenosides in adventitious roots differed among the three Panax species. Total ginsenoside content of adventitious roots in P. quinquefolium, P. ginseng, and p. japonicum was 8.03, 15.7 and 1.2 mg/g dry weight, respectively. Among the three speices, adventitious roots in P. quinquefolium produced hig-hamount of ginsenosides. The pattern of ginsenoside fractions between P. ginseng and P. quinquefolium was similar but the amount of ginsenoside differed between the two, While, in P japonicum, total ginsenoside content was very low and some ginsenosides such as ginsenoside Rb2 and Rf were not detected. Conclusively, we demonstrate that same culture condition was required for induction and elongation of adventitious roots of three ginseng species but growth of adventitious roots and their ginsenoside production were different among them.
