Cytological Effects of Herbicidal and Fungicidal Pesticides on Root Apex Meristem Cells of Triticum Aestivum

Using the example of 2-day-old Triticum aestivum seedlings, grown in hydroponic culture, the cytological effects of pesticides with various mechanisms of the damaging were studied: the herbicides metribuzin, tribenuron-methyl, fenoxaprop-P-ethyl and the fungicides tebuconazole, epoxiconazole, and azoxystrobin. All pesticides showed a dose-dependent inhibitory effect on the development of the roots of Triticum aestivum, but did not affect the mitotic activity and did not reduce the mitotic index of root apex meristem cells. Herbicides and fungicides affected the duration of metaphase, anophase, prophase, and cytokinesis activity in the root apex meristem of the wheat, and these changes were specific for the six studied preparations. Under the influence of all pesticides, the number of abnormal cells increased significantly, to the greatest extent (10–12 times compared with control - distilled water) under the influence of herbicides tribenuron-methyl and phenoxaprop-ethyl and fungicides azoxystrobin and epoxiconazole; to a lesser extent - under the influence of metribuzin and tebuconazole (6–7 times). For all studied pesticides the manifestation of cyto- and genotoxicity, including both clastogenic and aneugenic effects, was revealed in relation to the non-target plant Triticum aestivum. Under the influence of pesticides, structural anomalies, caused by chromosome breakdown (bridges, fragments, micronuclei) and spindle damage (lagging chromosomes and their fragments, uneven chromosome separation) were detected in the cells of the Triticum aestivum root apex meristem.

Cytological assays for the evaluation of genotoxicity in plants: A review

Plants model are recognized as excellent genetic models to detect environ-mental mutagens and are frequently used in xenomoitoring studies. Several assays such as chromosomal aberration assay, micronucleus assay and comet assay are used for detecting the mutagenicity, cytotoxicity and genotoxicity of environmental pollutants. It is easily handled and has advantages over other short-term tests that require pervious preparation of tested samples as well as the addition of exogenous metabolic system. Plants model also enables to evaluate different end points such as chromosomal aberration assay (CAA), micronucleus assay (MNA) and comet assay (CA) that have been used to detect genotoxicity of environmental pollutants. In addition, plants model provides important information to evaluate action mechanisms of an agent about its effects on the genetic material (clastogenic and/or aneugenic effects). It has been widely used to assess the impacts caused by xenobiotic, characterizing an important tool for environmental monitoring studies. The present review describes the two important assays using plant models that are appropriate and efficient cytogenetic materials for the detection of geno-toxicity of environmental pollutants.