Effects of radioactive contamination on plant populations and radiological protection of the environment

Abstract

Abstract.Data from large scale field experiments are clearly highly relevant to the development of a new system for radiological protection of the environment. Therefore, an actuality and severity of population-level effects within radioactively contaminated areas are among key problems today. The results of long-term field studies in the Bryansk Region, Russia, affected by the Chernobyl accident, and at the Semipalatinsk Test Site, Kazakhstan are discussed. The results of these studies clearly indicate that plant populations growing in areas with relatively low levels of pollution are characterized by the increased level of both cytogenetic disturbances and genetic diversity. Genetic processes in exposed populations lead to increasing of phenotypic diversity and rapid selection of novel phenotypes favoured in changed environment. In particular, radioactive contamination of the plants' environment activates genetic mechanisms, changing a population's resistance to exposure. However, in different radioecological situations, genetic adaptation to extreme edaphic conditions in plant populations could be achieved with different rates. Such evolutionary effects are of special concern because they are able to negatively affect population dynamics and local extinction rates. A development of a system for protection of the environment from ionizing radiation should be based on a clear understanding of these effects and their contribution to biological response.

Impact assessment of long-term chronic radiation exposure on plant populations

“…6). Similarly, the seeds from the crested hairgrass populations that have been experiencing radiation exposure for more than a half century at the Semipalatinsk Test Site and are bearing the elevated levels of cytogenetic abnormalities do not show any reliable increase in resistance to the additional acute -ray exposure [7]. Moreover, the results remain qualitatively the same after the considerable variation in the dose rate of acute irradiation (from 2970 Gy/h to 39 Gy/h).…”

“…Aberrant cell frequency in root meristem of germinated seeds collected from these populations significantly exceeds the reference level and shows correlation with the dose absorbed. Compiled with data from other our studies [2][3][4]7], these findings indicate that an increased level of cytogenetic disturbances is a typical phenomenon for plant populations growing in areas with relatively low levels of pollution.…”

“…Therefore, a well-directed accumulation of knowledge is needed and appropriate experimental data analysis is necessary. Previously completed and ongoing field studies that have been carried out in Laboratory of Plant Ecotoxicology, RIARAE with different species of wild and agricultural plants are presented in [2][3][4][5][6][7]. A wide range of radioecological situations and climatic zones have been covered in frames of this work.…”