The effects of ginsenosides Rg1 and Rb1 of Panax ginseng on mitosis in the onion root tip cells as well as on the rate of DNA synthesis in onion seedlings were studied. Results obtained from the concentration and time course study in bulb and seedling root tip cells indicate that Rg1 promotes and Rb1 inhibits mitosis, both being dose-dependent. The promoting effect of Rg1 on the rate of DNA synthesis was observed at the peak hour which occurs at the same time as that of the control. Rb1 was found to shift the peak hour of DNA synthesis to a later period of the experiment. These results are in agreement with the results obtained from the study of the cell cycle by pulse labelling and auto-radiography, which show that Rg1 shortens the mitotic cell cycle and S period while Rb1 lengthens them. They in turn increase and decrease the mitotic indices respectively.
DURATION OF MITOTIC CELL CYCLE IN THE ROOT TIP CELLS OF MALE RUMEX ACETOSA
