Cytogenetic effects of imazethapyr herbicide on the root meristem cells of Allium cepa L

In this study, the mitotic division and chromosomal effects of İmazethapyr herbicide on Allium cepa root meristematic cells were investigated. In Allium root growth inhibition test, EC50 value was determined as 20 ppm and 0.5xEC50, EC50 and 2xEC50 concentrations of Imazethapyr herbicide were introduced to onion tuber roots and distilled water and methyl methane sulfonate (MMS, 10 mg/L) used as a negative and positive control, respectively. Since A. cepa cell cycle is 24 hours, application process was carried out 24, 48, 72 and 96 hours. Mitotic index and mitotic phase frequences were calculated separately for each dose introduced. All the doses applied showed the decreased mitotic indexes as to control group and these declines were found to be statistically meaningful. While chromosome laggards, disturbed anaphase-telophase, stickiness and anaphase bridges were observed in anaphase-telophase cells, pro-metaphase, c-metaphase, polyploidy and binuclear cells were observed in other cells. The results were also analyzed statistically by using SPSS for Windows, and Duncan?s multiple range tests were performed. These results indicate that imazethapyr herbicide exhibits cytotoxic activity but not genotoxic activity (except 10 ppm) in A. cepa root meristematic cells. Key Words: İmazethapyr, Allium cepa, mitotic index, mitotic anomalies