Accumulation and localization of alkali elements in Lentinula edodes studied by PIXE analysis

The spatial distributions of potassium and rubidium in Lentinula edodes mushrooms contaminated with radioactive cesium were measured using particle-induced X-ray emission (PIXE) analysis by a beam scanning technique with a submillimeter sized proton beam to study relationships in elemental concentration in the mushrooms between radioactive cesium and other alkali elements. The results of PIXE analysis were compared with the spatial distribution of radioactive cesium in the samples measured by an autoradiographic method. Radioactive cesium was not uniformly distributed and strongly concentrated in the peripheral region of pileus of the mushroom while the elemental maps evaluated from PIXE analysis showed that potassium and rubidium are highly accumulated in the same area as radioactive cesium. The present results suggest a common mechanism of the accumulation of alkali elements including radioactive cesium in Lentinula edodes mushrooms.