Uptake, allocation, accumulation and ecological implications of 85Sr in bracken (Pteridium aquilinum L. Kuhn)

Solutions containing 85Sr were applied to cultivated Pteridium (bracken) plants. The radionuclide was applied to either root, rhizome tip or frond tips. Less 85Sr was taken up by the fronds than by the other two plant parts. The fate of the radionuclide differed for different modes of uptake, but for all routes of entry 85Sr was taken up, transported around the plant and behaved as a calcium analogue, in that it accumulated in old and senescent material. Little subsequent recycling to second generation fronds occurred, indicating that 90Sr would accumulate in senescent fronds and be transported into the litter layer, thereby becoming environmentally available. Leaf decay would render 90Sr taken up by bracken environmentally available again far more rapidly than 137Cs in this important component of European ecosystems.