Evaluation of Genotoxic Effects of Commonly Used Fertilizers in Allium cepa Root Cells by Comet Assay
The comet (single-cell gel electrophoresis) is a useful method for providing a source of information about the genotoxic potential of pollutants. In this study, we aimed to determine the effects of different concentrations of ammonium sulfate (AS) and diammonium phosphate (DAP) on root growth of Allium cepa and to detect the genotoxic potencies of these fertilizers on root cells. Our results show that both AS and DAP enhance root growth at the concentration of 640 ppm but cause significant decreases in root length and weight at higher concentrations (1280, 1920, and 2560 ppm). In addition, exposure to AS and DAP at 1280 and 2560 ppm for 48 h gave rise to a significant increase in DNA damage in Allium cepa root cells. It was found that DAP exerted a stronger genotoxic effect than AS, especially at 2560 ppm. Taken together, our findings suggest that high application rates of chemical fertilizers in agricultural systems not only inhibit plant growth but also can increase DNA damage in plants.