Changes in endogenous cytokinin levels in partially synchronized cultured tobacco cells.

During the course of partially synchronized cell divisions in cultured tobacco (Xanthi) cells the amount of endogenous cytokinins in the butanol-soluble fraction increased 5 to 10 times in 3 hours and paralleled the increase in frequency of mitosis. Among three cytokinins detected in tobacco cells, the activity corresponding to the R(F) of authentic zeatin in thin layer chromatography changed in parallel with the mitotic index.