[The effect of oxidative stress on nitrosomethylurea-induced mutagenesis in sunflower Helianthus annuus L].

The effect of hyberbaric oxygenation on mutagenicity of nitrosomethylurea (NMU) was examined. It was shown that in the regimes studied, hyperbaric oxygenation enhances the NMU mutagenic effect both on the nuclear and on the plastid genetic material of sunflower, but do not increase intensity of free-radical reactions and do not induce plastid mutations and chromosome aberrations per se. At high concentrations inducing chromosome aberrations (0.03%), NMU was shown to enhance the level of free-radical processes. Possible mechanisms of the increase of NMU-induced mutagenesis by hyperbaric oxygenation are discussed.