Effects of NH4+:N03-ratio and ionic strength on adventitious root growth and ginsenoside production in bioreactor culture of Panax ginseng CA!Meyer

Adventitious roots of ginseng (Panax ginseng C.A. Meyer) were cultured in bioreactors with variations of culture conditions. In the experiment on NH4+: NO3- ratio in the culture medium, ginsenoside production was affected by NH4+: NO3- ratios in the culture medium, showing greatest productivity at 18.5 mM NO3- without NH4+. Containing NH4+ in the culture medium significantly inhibited ginsenoside production. Highest root growth was also observed when NO3- was used as the single nitrogen source, while lowest root growth was observed when only NH4+ was used as nitrogen source. These results indicated that nitrate played an important role both in adventitious root growth and in ginsenoside production. Ionic strength in the culture medium also greatly influenced root growth and ginsenoside production. In macro-elements, high concentrations of K+, Mg2+, and Ca2+ in the culture medium favored root growth and ginsenoside production. On the other hand, root growth and ginsenoside productivity were improved by decreasing the concentrations of micro-elements in the culture medium. Increases in CoCl2, CuSO4, KI, and ZnSO4 concentration by five times those in MS medium resulted in significant reduction of root growth and ginsenoside production, while five-time increase in MnSO4 concentration resulted in the improvement of root growth and ginsenoside production.