Peculiarities of 137Cs translocation in higher plants under environmental and laboratory conditions

Accumulation of technogenic 137Cs in higher plant roots and above-ground part and comparison of 137Cs and 40K transfer from roots to the above-ground part of plant as well as distribution within above-ground part of plant under environmental conditions were investigated. Parallely, the results of the investigations of 137Cs accumulation in the roots and shoots of test-organism Lepidium sativum L. in the model hydroponic system aqueous solution-solid phase-plant were analyzed. Peculiarities of transfer of this radionuclide from roots to shoots during the entire plant growing period under experimental conditions were determined. 137Cs activity in the tested plants of meadow ecotop was on an average 6-fold lower than in the plants of swamp and 10-fold lower than in the plants of forest ecotop. Differences in 137Cs and 40K transfer from roots to the above-ground part of plant and their distribution in plants indicate particular biological metabolism of these radionuclides in plants. Increased levels of 137Cs in soil practically did not affect the 40K transfer from roots to the above-ground part of plants. The results of investigations under natural and laboratory conditions show that increasing contamination of growth medium with 137Cs caused higher accumulation of this radionuclide in roots but its transfer from roots to the above-ground part of plant decreased or changed insignificantly. 137Cs transfer from roots to above-ground part under natural (Artemisia vulgaris) and laboratory (Lepidium sativum) conditions was rather similar

Effects of 137Cs low level exposure (internal and external) doses on plants

Effects are described of internal exposure doses of ionizing radiation in above- and underground parts of test plants under natural conditions and in roots of Lepidium sativum L. from accumulated 137Cs under laboratory conditions. In the region most contaminated after the Chernobyl accident, in the tested 10 plant species for 137Cs ionizing radiation the internal exposure doses 3.5 times exceeded those in the Ignalina Nuclear Power Plant environment. Under laboratory conditions the effect of low internal (0.6-600 mSv) and external (40-5500 mSv) exposure doses from 137Cs on garden cress, Lepidium sativum L. roots was, practically, the same. Both internal and external exposure doses stimulated the plant root growth by 12 and 33%, respectively. Different effect of external and internal exposure on the developing plant cells was observed by analyzing the results of morphometric investigations of the primary root cap cells of Lepidium sativum L

Influence of 137Cs and 90Sr on vegetative and generative organs of Lepidium sativum L. and Tradescantia clone 02

The impact of 137Cs and 90Sr activity concentrations from 0.4 to 400 kBqźL-1 and from 1 to 200 kBqźL-1, respectively, on seed germination of Lepidium sativum was insignificant; however, all concentrations of 137Cs and 30 kBqźL-1 concentration of 90Sr slightly stimulated root growth. The accumulated 137Cs and 90Sr stimulated shoot and parenchyma cell growth; 137Cs suppressed RNA-polymerase II activity, and 90Sr, on the contrary, stimulated it. Different genotoxic effects on Tradescantia clone 02 stamen hair cells were observed with comparable 137Cs and 90Sr activity concentrations. Activity concentrations of 137Cs from 0.001 to 1.3 kBqźL-1 were more effective in Tradescantia clone 02 stamen hair cell reproduction, whereas the studied activity concentrations of 90Sr (from 0.002 to 640 kBqźL-1) induced more mutations. -------------------------------------------------------------------------------