Dose-dependent effects of isotopic exchange of tritium in the process of willow vegetation

Abstract

The paper is devoted to the study of the kinetics of tritium redistribution between living and inanimate matter of white willow in the “greenhouse” experiments. It was shown that the concentration of tritium in the aquatic environment significantly affects the kinetic parameters of its assimilation in the organic and inorganic matter of the organism of the white willow (Salix alba L.). The kinetics of the influx of tritium from the aqueous nutrient into the intracellular juice, the organic phase of plants, and transpiration fumes, depending on the concentration of the superheavy hydrogen isotope, are described. Dose-dependent effects were identified, accompanied by fractionation of hydrogen isotopes in all components of the biosystem - the aquatic food environment, intracellular juice, transpiration fumes, and in the organic phase. It was found that with an increase of the initial specific activity of aqueous feeding solution (by 8.6 times): the rate of tritium removal from it and from intracellular juice increases (by 14.8 and 15.6 times, respectively), the degree of assimilation of this isotope into intracellular juice decreases (by 41.3 times), and its the part that enters the organic phase of wood (1.3 times) decreases the relative proportion of tritium in transpiration water (5.7 times). The existence of physiological barriers that sharply and significantly limit the assimilation of tritium into the components of the willow has been proved. Thus, the value of the barrier during the migration of this isotope of hydrogen into the intracellular juice reaches 15 % and only 18 - 25 % of tritium gets from the external water into the organic phase.