Investigation of the potential toxic effects of prometryne herbicide on Allium cepa root tip cells with mitotic activity, chromosome aberration, micronucleus frequency, nuclear DNA amount and comet assay

Abstract

In the present study the potential toxic effect of prometryne herbicide was examined by investigating mitotic index, mitotic phase, chromosomal abnormalities, micronucleus frequency, 2C DNA content, and comet assay on the root tip cells of Allium cepa. The roots were exposed to 2, 3, 4 and 6 gl(-1) concentrations within 12, 24 and 36 h. Mitotic index was markedly reduced by prometryne in each treatment group compared with the controls. The frequencies of mitotic phases have been changed. Prometryne significantly increased the anomaly cell percentage at all concentrations and application periods in comparison to their control. Mitotic abnormalities were recorded as disturbed prophase, c-mitosis, stickiness, laggards and chromatid bridges. The micronucleus was observed at interphase and its frequency was calculated in the test solutions used. Prometryne decreased the 2C DNA amount in onion root tips. Furthermore, the comet assay was applied to analyze the single stand breakages. Nearly all of the applied concentrations of prometryne enhanced DNA damage. In many cases negative correlation was found between 2C DNA amount and DNA damage; however, positive correlation was found between micronucleus formation and DNA damage.