Toxic effect of Chromium on genotoxicity and Cytotoxicity by use of Allium Cepa L.

The genotoxicity and cytotoxicity of chromium was investigated using both morphological, root growth inhibition and chromosomal assays. The Allium cepa L. were exposed to different concentration of Chromium in different time interval (0.2, 2, 4, 8, 12.5 mg/l and control) and mean root length of onion were measured after 24h, 48h, 72h and 96h. EC-50 value were determined from the growth curve as 47%. The result indicate that EC-50 of chromium for 24h, 48h, 72h and 96h of exposure are 0.8, 5.4, 4.9 and 4.4 mg/l respectively. The results of mean root length was statistically evaluated by the analysis of least significant difference. There was significant decrease in root length as concentration increased in the experiment. Also the mitotic index decreased as concentration increased. Total chromosome aberrations increased significantly as concentration increased. The result demonstrate that Allium test is a useful screening test for the evaluation of toxicity of heavy metal.