[Mutagenesis of enzyme loci, induced in megaspores of Pinus sylvestris L. by ionizing radiation from the accident at the Chernobyl Atomic Power Plant].

Mutagenesis of alleles of 20-allozyme loci was studied using the electrophoresis methods in polyacrylamide gel in seeds of Pinus sylvestris within the 30 km zone of the Chernobyl NNP and the limits of contamination levels by Cs-137 from 5 up to 600 Cu/km (the absorbed doses being 0.5 to 10 Gy). The frequency of emergence of corresponding mutations which change the synthesis of enzymes in endosperms within the zone constituted on the average 2.7-10 per gene as compared with 0.6-10 in control version. Linear dependence was observed between low doses absorbed and the frequency of gene mutations, while in case of high doses this decreased. Genetic effectivity was 0.001 mutations/locus/Gy. Various radiosensitivity levels were shown among the loci studied. Spontaneous level of mutations frequency in P. sylvestris populations was found to be within the limits of 0.5 to 1.5 Gy under conditions of the 30 km zone. The high rate of mutagenesis was revealed in seeds of the first two post-accident reproductions.