Radiocaesium in fruitbodies and mycorrhizae in ectomycorrhizal fungi

Abstract

Fruitbodies of Suillus variegatus and Lactarius rufus and, at a maximum distance of 50 cm, the corresponding mycorrhizae, were collected on a rocky area in a coniferous forest. The tuberculate mycorrhizae collected close to S. variegatus fruitbodies were identified by the RFLP pattern to be S. variegatus mycorrhizae. In contrast the smooth brown mycorrhizae collected close to fruitbodies of L. rufus were found to be of various species — L. rufus, but also Russula sp. The 137Cs activity concentrations in fruitbodies and the fungal part of the tuberculate mycorrhizae of S. variegatus were about the same. A local enrichment of 137Cs within fruit-bodies was studied by collecting fruitbodies growing in clusters. Between 13 and 64% of the mean ground 137Cs deposition of the cluster area (400 or 625 cm 2) was found in the fruitbodies. This indicates that there might be an important fungal redistribution of 137Cs in the forest floor during the production of fruitbodies. The distribution of 137Cs within the fruitbodies was heterogenous. For example in Cortinarious armillatus, the 137Cs level in the cap was 2.7 times higher compared to in the stripe.