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.

中文翻译：

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影响铯转移因子到香菇（因素香菇）培养在锯末介质

放射性铯137（137Cs）转化为在床上原木上种植的香菇（香菇）的转移因子（TF）差异很大。因此，本研究使用稳定的铯133（133Cs）和锯木屑培养基（含5％米糠）作为模型，研究了哪些因素影响TF，而133Cs TF与底木栽培相似。发现在模型木屑培养基中，Cs浓度和养分浓度（由氮浓度表示）与TF有关。此外，在对数种植和模型木屑培养基种植中，使用总137Cs和133Cs浓度计算出的TFs不同，而使用可交换137Cs和133Cs浓度计算出的TFs在木屑培养基培养中是相同的，表示培养基中可交换的Cs是子实体Cs的来源，前者的差异是由于存在其他无法吸收的Cs的化学形态。蘑菇农场TF的一个目的是在河床对数栽培开始时确定子实体137Cs的浓度，因此，考虑树木中137Cs浓度的未来变化，讨论了TF的预测方法。