Uptake of potassium ions by normal and crown-gall-tumor cells of Vinca rosea grown in tissue culture.

Potassium uptake in normal and crown-gall tissue culture cells of Vinca rosea L. (Cathalanthus roseus G. Don.) was studied. When grown on White's medium for 14-20 d, the tumor cells had a higher K(+) content that did the normal cells. At this logarithmic stage of growth, the rate of K(+) uptake was greater in normal cells than in tumor cells. K(+) uptake in both normal and tumor cells was inhibited substantially by 2,4-dinitrophenol but only slightly by oligomycin, NaF, and N,N'-dicyclohexyl carbodiimide. When the internal K(+) content of the cells was varied by growing the tissue in White's medium supplemented with varying concentrations of K(+), the rate of K(+) uptake in normal cells increased with decreasing internal K(+) concentrations. In contrast both lines of tumor cells failed to show this normal increase in the rate of K(+) uptake with decreasing internal K(+) concentrations.