| Abstract: | The object of this investigation was the mutagenic effect of kinetin (6-phurphuryl-aminopurine) on chromosomes of Crepis capillaris L. Dry seeds were soaked in the 0.05% kinetin solution for 4, 6 and 8 hours before the irradiation with X-rays. It is observed that soaking of dry seeds in kinetin solution stimulates the appearance of chromatid aberrations for almost two hours earlier, than in the control (soaking seeds in water). A regular increase of the chromatid-type rearrangements with increasing the duration of soaking in the kinetin solution was observed (3.3%, 16-20% and almost 50% at 4 hours; 6 hours' and 8 hours' soaking respectively). This increase is indicative for the effect of kinetin on the processes taking place in the cell before the irradiation. Apparently kinetin stimulates the onset of the stage S for a certain proportion of cells, and thus at the moment of irradiation the cell population is at the asynchronous state. A considerable radioprotective effect of kinetin was observed in all the variants of the experiment, which is not associated with the capacity of stimulating the initiation of chromatid aberrations inherent in kinetin. Kinetin alone (without irradiation) exerts no mutagenic effect on the cells of Crepis capillaris. |
