THE PHYSIOLOGY OF BASIDIOMYCETE LINEAR ORGANS .3. UPTAKE AND TRANSLOCATION OF RADIOCESIUM WITHIN DIFFERENTIATED MYCELIA OF ARMILLARIA SPP GROWING IN MICROCOSMS AND IN THE FIELD

Autoradiography and quantitative image analysis were used to measure C s-137 distribution and translocation through mycelia of A. gallica Mar xmuller & Romagn. and A. ostoyae (Romagn.) Herink growing in small mic rocosms in the laboratory. Rhizomorphs of A. gallica were labelled wit h Cs-134 the field, and the translocation of radiolabel measured after excavation and destructive harvesting. The flux of radiocaesium throu gh rhizomorphs was estimated to be greater than through undifferentiat ed hyphae, and greater through rhizomorphs growing in the field than t hrough rhizomorphs grown across homogeneous media in the laboratory. D ifferentiation within mycelia resulting in melanization or rhizomorph formation gave rise to increased heterogeneity in the Cs-137 distribut ion through laboratory microcosms compared with that through microcosm s containing undifferentiated mycelia. Radiocaesium leaked from undiff erentiated hyphae into the surrounding medium, but melanized regions o f the mycelium appeared to be conservative for radiocaesium. These fin dings provide further evidence for the importance of filamentous fungi in determining the distribution and rate of release of radiocaesium c urrently present in the environment as a result of weapons testing and the accident at the Chernobyl nuclear reactor.