Changes of the genetic structure in chronically irradiated scots pine populations

Summary: Background. The vast forest areas were affected by radioactive fallout of the Chernobyl accident. Data about the long-term effects of chronic radiation exposure are insufficient, as well as knowledge about its influence on the genetic structure of populations. Study of isozyme polymorphism allows us to identify how chronic low-dose radiation exposure affects the genetic structure of plant populations and to develop new methods for assessing the biological effects of anthropogenic impact on terrestrial ecosystems. Materials and methods. The study was conducted in six sites in the Bryansk region (4 radioactively contaminated and 2 reference ones). The method of vertical electrophoresis in PAAG was used for estimation of polymorphism of three enzymes involved in metabolic pathways. Activity of enzymes in seeds of Scots pine was assessed by spectrophotometry. Results. The frequency of mutations in isozymes loci increased along the level of radiation exposure (7-130 mGy/year), as well as some characteristics of the genetic structure of populations. Biochemical activity of studied enzymes does not depend on the level of dose absorbed in the generative organs of pine. Conclusions. It was found that the frequency of mutational events in loci of catabolic/anabolic enzymes and in the loci of previously studied antioxidant enzymes increases along the level of radiation exposure. The degree of the biological effect of chronic exposure was different in groups of catabolic/anabolic enzymes and antioxidant enzymes. Radiation exposure contributes to changes in the genetic structure of Scots pine populations