Effects of cadmium on root growth, cell division and micronuclei formation in root tip cells of Allium cepa var. agrogarum L. Efectos del cadmio en el crecimiento radical, división celular y formación de micronúcleos en células apicales radicales de Allium cepa var. agrogarum L.

The effects of various cadmium (Cd) concentrations (10, 50 and 100 μM) on root growth, cell division and micronuclei formation in root tip cells of Allium cepa var. agrogarum L. were in- vestigated to better understand the processes of Cd-induced apopto- sis. The results indicated that 10 μM of Cd had an obviously passive influence on root growth during the 24 h treatment, and that the influence was even more serious with increasing Cd concentrations and duration of treatments. The mitotic index decreased with in- creasing Cd concentration and duration of treatments. Cadmium induced c-mitosis, chromosome bridges, chromosome stickiness and micronuclei. The frequency of cells with these disorders varied with prolonging the duration of treatments and increasing Cd concentra- tions. Micronuclei (MN) are biomarkers of genotoxic events. Our analyses proved the presence of a number of cells carrying micro- nucleus, and the elimination of the exceeding material itself, after exposing A. cepa var. agrogarum L. root tips to the Cd treatments. A number of micronuclei and nuclear anomalies were noticed at 10 μM Cd. Inferences about the implications of the elimination of ge- netic material from micronuclei, such as cell viability and apoptosis, are also presented.