Spectroscopic and genotoxic assessment of Imazamox herbicide-induced alterations in the Allium cepa model system

Abstract

Imazamox (IMA), an imidazolinone herbicide, is commonly used to control weeds in crops such as sunflower, beans, peas and chickpeas. In the current study, the effects of 24 h exposure to different IMA concentrations (125, 250, and 500 ppm) on Allium cepa root tips were investigated at molecular level using Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy and genotoxicity tests. The ATR-FTIR results indicated that all doses of IMA caused an increase in lipid peroxidation levels and a decrease in tissue metabolic activity, along with a decrease in protein, carbohydrate and nucleic acid content and an increase in saturated lipid content. In addition, IMA caused important structural modifications including shortened lipid chains, reduced membrane disorder and fluidity, increased carbonyl content and lipid to protein ratio. Principal component analysis (PCA) and Hierarchical cluster analysis (HCA) confirmed these spectral alterations by effectively distinguishing control and IMA-treated groups across different doses. Genotoxicity assays further demonstrated that IMA induced various mitotic abnormalities, such as c-mitosis, irregular metaphase and micronuclei formation in A. cepa root tips. The observed structural and genotoxic changes were clearly dose-dependent, with higher concentrations causing more severe effects. These findings highlight the potential risks associated with IMA exposure and suggest that more caution should be exercised in the use of this herbicide. Furthermore, the successful application of ATR-FTIR spectroscopy to detect herbicide-induced molecular changes suggests that this technique, combined with chemometrics and A. cepa as a bioindicator model system, offers a rapid and reliable biomonitoring tool to evaluate pesticide toxicity.