Estimation of DNA damage in the roots of Allium cepa exposed to heavy metals using comet assay

Higher plants were used as a bioindicator of environmental toxicity to estimate the severe problems related to the health of living organisms and the environment. Allium cepa plant was used to evaluate the DNA damage caused by heavy metal exposure, the roots of A.cepa plant. They were treated with four concentrations (5, 10, 20 and 25 ppm) for each of the metals Cadmium, zinc, copper and lead. At the same time, concentrations (50, 100, 200 and 500 ppm) were used for the preservative (sodium benzoate). The comet assay, a sensitive and suitable test for assessing DNA damage caused by chemical exposure, was used in this study. The Comet's six characteristics were measured: Head intensity, Head DNA%, Tail length, Tail intensity, Tail DNA% and Tail moment. The results showed that the metals are causing the DNA damage of meristematic cells of the roots of the A. cepa plant, depending on the tail length from most to least effective Cadmium> zinc > sodium benzoate > copper > lead > wastewater. I consider that it is not necessary to write down these values. The results of this study confirm that the meristematic cells of the roots of A. cepa are a suitable model for detecting DNA damage analyzed by the comet assay.
 
Keywords: Toxic metals - Bio-indicator - Single cell gel electrophoresis (SCGE)