Chromosome numbers of Saintpaulia ionantha plantlets regenerated from leaves cultured in vitro with caffeine and colchicine

Summary Parts of Saintpaulia ionantha leaves were cultured on a medium supplemented with different concentrations of colchicine or caffeine. The explants were transferred to a control medium without these chemicals after different periods of time. The chromosome number of the regenerated plantlets was counted. In all the experiments, polyploid plantlets were found, but the percentage of them was higher with colchicine. There were no differences in frequency of polyploid plantlets among treatments with the same chemical. In both cases a high percentage of cytochimeric plantlets was observed and possible explanations of their occurrence are given.