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The effect of γ-radiation on the growth and cytogenetic endpoints of Allium cepa L. seedlings in a long period after irradiation in absorbed doses from 1.0 to 10.7 Gy were examined. The chromosome aberration rate was most sensitive to the radiation: it increased immediately after exposure at all doses. In the recovery period (up to 216 h) after irradiation, the chromosome aberration frequency naturally decreased but at the end of experiment in maximum doses remained above the control values. The impact of the initial level of chromosome aberrations on the inhibition of onion roots growth in the long terms after irradiation is discussed. [ABSTRACT FROM AUTHOR]

The effect of γ-radiation on the cytogenetic parameters of root meristem cells of onion seedlings was studied in laboratory experiments (Allium-test). An increase in the overall frequency of chromosomal aberrations and micronucleus frequencies in seedling cells at low γ-radiation doses (≤0.1 Gy) was detected for the first time. At a maximum absorbed dose of 13 Gy, chromosomal aberrations were detected in the majority of cells in the anaphase and telophase stages of the cell cycle, and the number of cells with multiple aberrations increased. The main contribution to the overall frequency of chromosomal aberrations, in addition to multiple aberrations, is made by the bridge-type aberrations, fragments, and lagging chromosomes. The data obtained allow using the cytogenetic indices of Allium cepa seedlings to assess the biological effects of lowdose γ-radiation. [ABSTRACT FROM AUTHOR]

We investigated the sensitivity of resting eggs of the cladoceran Moina macrocopa to the effect of ionizing radiation during the reactivation of the eggs. The study showed that the resting eggs during reactivation are more vulnerable to irradiation than the resting eggs in a stage of deep dormancy. The decrease in the efficiency of egg reactivation was observed at high doses, the growth rate of juveniles, fecundity, and the number of produced clutches by females strongly decreased when resting eggs at the reactivation stage absorbed doses of 64 Gy and higher. [ABSTRACT FROM AUTHOR]