[V.I.Vernadskiĭ's theory of the biosphere and modern problems of radioecology].

The importance of Vernadsky's scientific heritage for the present stage of science development was substantiated. His role in the formation of radioecology as an independent scientific discipline was emphasized. The ecological consequences of an anthropogenic increase of the radiation background and the prospects of nuclear energy development were considered.

[The change in efficiency of protective measures for reduction of 137Cs accumulation by agricultural plants in various periods after the Chernobyl accident].

Dynamics of 137Cs transfer factors to plants and the effects of protective measures on this radionuclide accumulation in the agricultural production is estimated on the example of the south-western regions of Bryansk District. Three periods in decreasing the 137Cs content in plants during 20 years after the Chernobyl accident are identified. The contribution of radionuclide decay, natural biogeochemical processes and protective measures aimed at reduction of the 137Cs accumulation in agricultural plants during various periods after radioactive fallout is shown.

[Methodology for an assessment of derived radiation levels for agrocenoses].

Radiation protection of agrarian ecosystems should be considered as an integral part of a system for radiation protection of environment, with a special concern to agroecosystems' features. A methodology is proposed for an assessment of maximum permissible doses of radiation impact for agrocenoses based on an unified analysis of available data about effects of radiation in cultivated plants. It is considered as a component of radiation protection system for agricultural ecosystems.