Determination of genotoxic damages of picloram and dicamba with comet assay in Allium cepa rooted in tissue culture and distilled water

Abstract

Background: Many genotoxicity tests allow us to understand the mechanism of damages on genetic material occurring in living organisms against various physical and chemical agents. One of them is the Comet test. The current study aimed to evaluate genotoxic damages by picloram and dicamba to root meristems of Allium cepa utilizing comet assay. Methods and Results: Two different protocols were used for rooting and auxin/pesticide application. (i) A. cepa bulbs were rooted in MS medium and then treated with MS medium (control) and 0.67, 1.34, 2.01, 2.68, 3.35, 4.02, and 8.04 mg/L of Picloram and Dicamba using aseptic tissue culture techniques. (ii) A. cepa bulbs were then rooted in bidistilled water and treated with 0 (control), 0.67, 1.34, 2.01, 2.68, 3.35, 4.02, and 8.04 mg/L of Picloram and Dicamba in distilled water. The A. cepa root tip cells in both treatment groups were examined using comet test to find the possible DNA damaging effects of Picloram and Dicamba. The results obtained at all the concentrations were statistically compared with their control groups. Almost at all the concentrations of Picloram and Dicamba increased comet tail intensity (%) and tail moment in roots treated in MS medium. Two highest concentrations revealed toxic effect. On the other hand, DNA damaging effect of both auxins was only noted on the highest concentrations (>4.02 mg/L) in roots treated in distilled water.Conclusions:This study approve and confirm genotoxic effects of tow growth regulators on plants.