Contribution of the clastogenic effect to mitotic disruption in Allium cepa root apical meristem was evaluated in laboratory biotest when exposed to ionizing radiation of a soil sample from 30-km zone of the Chernobyl Nuclear Power Plant, in comparison with genotoxicity of hydrogen peroxide as an oxidizing agent. A range of oxidant concentrations (0.03–150 mmol/l) and radiation levels (equivalent dose rates 0.3–1.53 μGy/h) were tested. Decomposition of the mitotic pathologies frequency into spectrum with allocation of the clastogenic effect share made it possible to identify differences in genotoxicity for the active factors. A greater contribution of the clastogenic component (60–76%) to the spectrum of mitosis disorders was observed under the influence of ionizing radiation compared to the oxidant effect of (36–51%). Cytogenetic features of the clastogenic effect were analyzed according to existing concepts of the molecular mechanisms of chromosome aberration formation. Cytogenetic index “proportion of clastogenic effect”, measured by a simple method of cytogenetic analysis with undifferentiated chromosome staining, is recommended as a sensitive informative indicator for characterizing the stress reaction profile in conditions of environmental pollution by genetically active pollutants of various natures.
Stolbova et al. (Wed,) studied this question.