THE CYTO- AND GENOTOXIC EFFECTS INDUCED BY SULPHATES IN Allium cepa L.

The scope of this paper is to assess the cyto- and genotoxic effects of sulphate on Allium cepa mitosis for root meristem. Three different concentrations of sodium sulphate (i.e. 0,1%; 1% and 5%) have been used, in which the onion bulbs were immersed for different periods of time such as 6, 24 and 72 hours. In the end of the experiment the harvested root tips were prepared according to Feulgen's squash technique and using Schiff reagent. The cytotoxic effects of sulphate were investigated by calculating the mitotic index and also through the analysis of chromosomes alterations during the mitosis. The phase ratio of cells undergoing mitosis in all the phases is estimated for all variants. For microscopy investigations it was used a Novex Holland B microscope with digital camera included. The cytological analysis realized on Allium cepa revealed a strong decrease in the mitotic index due to sulphate treatments which is more intense with the time of exposure. Moreover this phenomenon is associated with the appearance of different chromosomal complement alterations including the appearance of highly condensed chromatin. The mitotic index and genotoxic observations over the chromosomes can also be correlated with phase ratio of cells undergoing mitosis.