Exposure of Pisum sativum L. Seeds to Methomyl and Imidacloprid Cause Genotoxic Effects in Pollen-Mother Cells

SIMPLE SUMMARY: Pesticides are highly effective and widely accepted for safeguarding crops from pests, thus substantially enhancing agricultural productivity. In relation to the ecological toxicity caused by pesticides and their potential impact on nontarget entities, the purpose of this investigation was to assess the action of insecticides methomyl (ME), and imidacloprid (IM) on Pisum sativum L. The results indicate that these insecticides decrease the mitotic index (MI) and micronucleus frequency (MNF) in a dose-dependent manner. In addition, they exhibited a substantial genotoxic effect on P. sativum. Further studies to assess the impact of these insecticides on nontarget host plants should be explored at the molecular and biochemical levels in order to determine the mechanism of action of these insecticides. ABSTRACT: Pesticides are commonly used in modern agricultural systems to protect the plants from pests. Even though they potentially increase the crop yield, they have undesirable toxic effects on the consumers of plant products and nontarget host plants. However, there are limited studies to demonstrate the cytological changes induced by pesticides on plant cells. In the present study, we assess the cytological changes induced by two most commonly used insecticides, methomyl (ME) and imidacloprid (IM), using Pisum sativum L. as model plant system. P. sativum seeds were exposed to various concentrations of ME and IM (0.1, 0.2, 0.3, 0.4 and 0.5%) for 1, 3, and 6 h, and their effects on seed germination (SG), radicle length (RL), mitotic index (MI), chromosomal aberrations frequency (CAF), and micronucleus frequency (MNF) were studied. The results indicate that these insecticides decrease MI in root-tip cells, and increase in the MNF in pollen-mother cells in a dose-dependent manner. Additionally, insecticide-treated groups showed a dose- and time-dependent increase in the percentage of aberrant meiotic cells. Clumped nuclei (CNU), stickiness (STC), bridges (BRs), laggards (LGs), secondary association (SA), and precocious separation (PS) were among the frequently observed anomalies. The findings of this study indicate that commonly used insecticides ME and IM have substantial genotoxic effects on the root-tip and pollen-mother cells of P. sativum L.