Resistance of heather plants (Calluna vulgaris L.) to cesium toxicity

Natural soil Cs concentration is low and non-toxic to plants. The stable isotope Cs is present at concentrations close to 25 μg per g of dry soil [23] and only specially Cs-rich pollucite might cause environmental toxicity of Cs, as in areas of Manitoba [20]. Additionally, two radioisotopes of Cs, Cs and Cs, originating from industry, testing of thermonuclear weapons and from radiation accidents in nuclear power plants, such as that of Chernobyl, might be toxic and dangerous for plant organisms. Both these radionuclides, beta emitters with gamma component, are biologically important due to their energy levels, long half-life, ubiquitous production during the fission processes, and their tendency to follow the potassium cycle in nature. The influence of radiocesium and stable cesium on potassium uptake, transport and metabolism may be especially dangerous for plants because K is an essential macronutrient. The Cs ion shows nearly identical chemical properties as K and competes with K for cation binding sites in proteins [1]; this feature is important for K transport via carriers. Cs may inhibit K channels in the plasma membranes [23] and thus, it may induce K starvation in plants. The variation of Cs concentrations in plants among various soils is related to differences in Cs and K concentrations in soil solution, consistent with previous observations in hydroponic and pot trials [22]. The soil chemistry of cesium is more complex. As elucidated by Ehlken and Kirchner [10], Resistance of heather plants (Calluna vulgaris L.) to cesium toxicity Grażyna Bystrzejewska-Piotrowska, Agata Drożdż, Romuald Stęborowski