Factors affecting the cesium transfer factor to shiitake (Lentinula edodes) cultivated in sawdust medium

From the paper

Abstract

The transfer factor (TF) of radioactive cesium-137 (¹³⁷Cs) to shiitake (Lentinula edodes) cultivated on bed logs varies greatly. Therefore, the present study investigated which factors affect the TF using stable cesium-133 (¹³³Cs) and sawdust medium with 5% rice bran as a model, which had similar ¹³³Cs TFs to bed-log cultivation. It was found that the Cs concentration and nutrient concentration (represented by the nitrogen concentration) concerned with the TF in the model sawdust medium. In addition, the TFs calculated using total ¹³⁷Cs and ¹³³Cs concentrations differed in both bed-log cultivation and the model sawdust medium cultivation, while the TFs calculated using exchangeable ¹³⁷Cs and ¹³³Cs concentrations were the same in sawdust medium cultivation, indicating that exchangeable Cs in the medium is the source of Cs for the fruiting body and the former difference was due to the presence of other chemical speciation of Cs that could not be absorbed. One purpose of the TF on the mushroom farm is to determine the fruiting body ¹³⁷Cs concentration at the start of bed-log cultivation, therefore the prediction method of TF are discussed considering the future changes of ¹³⁷Cs concentrations in trees.