EFFECTS OF PLANT-GROWTH REGULATORS ON CELL-GROWTH AND GINSENOSIDE SAPONIN PRODUCTION BY SUSPENSION-CULTURES OF PANAX-QUINQUEFOLIUM

To understand the culture characteristics of suspended cells of Panax quinquefolium strain Q91625 in a shake flask, the dynamic changes of v arious parameters, such as pH, conductivity, wet and dry cell concentr ations, and the consumption of major nutrients during cultivation were first investigated. Then, the effects of plant growth regulators, i.e ,, 2,4-dichlorophenoxyacetic acid (2,4-D), indole-3-butyric acid (IBA) , and kinetin (KT), on the cell growth, saponin production and nutrien t utilization by the cultured cells were focused on. The results indic ate that the highest content of ginsenoside saponins, i.e., 10.9% by d ry weight, a relatively high production and productivity of saponins, being 602 mg l(-1) and 20.1 mg l(-1) d(-1) respectively, and the highe st product yield, i.e., 57.3 mg g(-1), were reached in the cell cultur es with a combination of the growth regulators of 2.5 mg l(-1) IBA and 0.1 mg l(-1) KT without addition of 2,4-D. This amount of saponin con tent is 70% higher than previously reported in the cell suspension cul tures, and also 68% higher than that obtained from the naturally culti vated 4-6-year-old plant. In addition, it was also understood that in the cultures with a relatively high production of saponins, the utiliz ation of the major nutrients, i.e., sugar, phosphate, ammonium, and ni trate, was at a relatively high level; and in the cultures with a rela tively high growth rate of the cells, the nitrate utilization seemed t o be much greater than in the other cases.