Cytotoxicity and Genotoxicity in Allium cepa L. Root Meristem Cells Exposed to the Herbicide Penoxsulam

Abstract

Penoxsulam is a new sulfonamide herbicide used on rice crops for annual grasses, broadleaf weeds, and sedges control, either grown through transplanting or direct dry or direct seeding methods of planting. In this study, Allium cepa ana-telophase and comet assay were used to examine the cyto-genotoxic effects of herbicide penoxsulam on A. cepa roots. A. cepa bulbs were exposed to ½xEC50 (12.5 µg/L), EC50 (25 µg/L) and 2xEC50 (50 µg/L) concentrations of penoxsulam for 24, 48, 72 and 96 h. Distilled water and 10 ppm of methyl methanesulfonate (MMS) were used as negative and positive control groups, respectively. Penoxsulam showed a cytotoxic effect by reducing root growth and mitotic index (MI), a genotoxic effect because it statistically increased chromosome aberrations (CAs, anaphase bridge, chromosomal laggards, polyploidy, disturbed ana-telophase and stickiness) and DNA damage as compared to control. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was also used for quantitative analysis of penoxsulam in A. cepa root meristem cells. Further molecular toxicological evaluations associated in the cyto-genotoxicity of penoxsulam on plants are needed to confirm these results