Role of mycorrhizal fungi in caesium uptake by plants

Abstract

It was demonstrated that rhizospheric processes involving mycorrhizal fungi can influence root uptake of radiocaesium. The ability of both ectomycorrhizal and endomycorrhizal fungi to limit radiocaesium availability to their host plants was considered. The ectomycorrhizal fungi grown in forest ecosystems were suggested to immobilize between 10 and 100 % of the total 137Cs activity. Radiocaesium was found to be accumulated in mycelium and fruit bodies of ectomycorrhizal fungi by simple diffusion and facilitated transport. Ectomycorrhizal fungi was considered to be effi- cient indicators of cumulative biogeochemical fluxes of radiocaesium in terrestrial ecosystems and thus to be appropriate candidates for phytoremediation technique. The significance of arbuscular mycorrhizal fungi as participants in radiocaesium cycle in the upper soil layers was discussed. Up to date, their role in processes of radiocaesium uptake by plants remains incompletely understood and controversial. It was demonstrated that arbuscular mycorrhizal fungi could accumulate 137Cs in their extraradical or intraradical structures, transport the radionuclide to their hosts and influence its distribution among plant roots/shoots. Depending on arbuscular mycorrhizal fungi and plant species used, the significant reduction or increase of radiocaesium transfer to aboveground plants biomass was found. The perspectives of arbuscular mycorrhizal fungi application in phytoremediation techniques were discussed.