Cytogenetic disorders of winter wheat root meristem cells under the action of moderate and high concentrations of N-nitroso-N-methylurea

Abstract

Aim. To study the frequency and spectrum of the cytogenetic disorders in Triticum aestivum L., induced by the effect of moderate and high concentrations of N-nitroso-N-methylurea. Methods. The seeds of winter wheat of cultivars Albatros odeskyi and Zymoiarka were treated with water solution of N-nitroso-N-methylurea in such concentrations as 0.005 %, 0.01 %, 0.025 %. A cytogenetic analysis of the cells of a root meristem was made with help of an anatelophase method. Results. The frequency of mitoses with chromosome aberrations amounted to 2.74–23.05 %, and it depended on the concentration of a mutagen and a plant genotype. A significant increase of the frequency of the aberrant cells was recorded as a result of the effect of the mutagen in the concentration 0.025 %, which was associated with a radiometric impact caused by the influence of a chemical mutagen in a high concentration. The spectrum of cytogenetic disorders contained mostly acentric fragments, the bridges of a chromatid type and the chromosomes which lagged behind. As the super-mutagen concentration increased, the spectrum expansion of the cytogenetic disorders took place at the expense of the even acentric fragments, micro-nuclei and acentric rings. Conclusions. The frequency of the chromosome aberrations, induced by the effect of NMU, exceeds the control level by 3.5–39.7 times, and it depends directly on the concentration of a chemical mutagen. N-nitroso-N-methylurea in the concentration equal to 0.025 % shows a radiometric effect which classifies a mentioned amount of the concentration of a super-mutagen as a high one. A serious increase of the indicator of the number of aberrations per aberrant cell appeared to be typical only when it was under the effect of a chemical mutagen in the highest concentration.