XVI International Botanical Congess

Radioecological monitoring of natural plant populations based on morphological and cytological changes has shown that ionizing radiation induces an increase in the level of mutation variability (rise in the number of aberrant cells and the degree of their injury) as well as various morphological and physiological abnormalities. Characteristic property of the observed mutagenic effects is multiple injuries of chromosome apparatus. Negative consequences of chronic irradiation manifested themselves most of all in the first post-accident years, then they gradually decreased that was caused by a reduction in dose loads and radioadaptation processes. Plant radiosensitivity is species-specific - it is defined by evolutionary established properties of species genetic systems and by ecologobiological salient features of species. The most radiosensitive are species of low ecological amplitude, high level of ploidy and apomicts, and species growing on the bound of natural distribution in marginal zones of distribution areas. But, the threat of disappearance under constant irradiation exists only for a few species, which are not dominants or codominants of communities. Therefore, their elimination, probably, will not have significant consequences for steady functioning of natural ecosystems.