Effects of the fungicide tridemorph on mitosis in Allium cepa.

A mitodepressive effect of Tridemorph on the meristematic cells of Allium cepa has been observed. This effect increases with the concentration of the fungicide and the length of treatment, until complete inhibition of cell division occurs under certain conditions. Furthermore, this chemical has been revealed as a strong c-mitotic agent, although there are clear differences between its action and that of colchicine and other c-mitotic drugs. Other important features are the alterations observed in the development of the different mitotic phases depending on the dose employed. A high degree of chromosome contraction has been observed since the cells are in prophase until they reach telophase. Multipolar anaphases and micronuclei, and anomalous chromosome separation and anaphase emigration are other important modifications induced by the treatment on the development of mitosis.