SUMMARY. The study of Arabidopsis ecotypes from the Chornobyl area demonstrated their enhanced resistance to cad-mium (Cd2+) and radiomimetics (bleomycin/zeocin). For instance, the seedlings of the Chornobyl ecotype Che07 demonstrated lower inhibition of root growth under Cd-induced stress. It was first determined that zeocin mainly affected the cells of the root meristem, whereas Cd2+ predominantly impacted the cells of the elongation zone. This differentiated response may result from variations in the stages of plant development, the specific action of genotoxic agents, and the activity of protective mechanisms in different growth zones of the roots. The analysis of DNA destruction and its ability to recover after processing with radiomimetics demonstrated the rapid (within three minutes) activation of repair mechanisms in the Chornobyl ecotypes Che5 and Che07. The enhanced expression of the cyclin gene CycB2;1 and poorer expression of the kinase gene CDKG1 after processing with bleomycin indicated the presence of changes in the regulation of the cellular cycle, specifically its arrest in the G2 phase. This adaptive response might be directed at inhibiting the transition to mitosis, which prevents the transfer of the damaged DNA to daughter cells. In Arabidopsis ecotypes from the Chornobyl area, there was activation of the specific antioxidant enzymes, which counteracts the oxidative stress and genome damage. It is assumed that Arabidopsis plants from the area of the Chornobyl nuclear power station employ unique mechanisms of adaptation to ecological stress and DNA damage, which may have been acquired due to the long-term impact of ionizing radiation. The investigation of plant resistance to ionizing radiation and heavy metals is relevant for the elaboration of phytoremediation strategies and may promote the development of biotechnologies to enhance plant resistance to other abiotic stress factors.
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