The activity concentrations of radiocesium (¹³⁷Cs) in wild mushrooms are reported to vary according to species, genus or ecological types. In addition, the concentration fluctuates among the same species collected within the same area. Therefore, we investigated whether the ¹³⁷Cs concentration of wild mushrooms would be (1) spatially biased, or (2) influenced by the ¹³⁷Cs or exchangeable potassium concentrations in the soils below. We set two survey plots 300 m apart in a Himalayan cedar forest in Tsukuba, Japan, where ca. 30 kBq/m² of ¹³⁷Cs was deposited after the Fukushima Nuclear Power Plant accident. From these plots, we collected fruit-bodies (fungal structures for spore production) of co-occurring Boletus hiratsukae, a mycorrhizal species, as well as from the soil below. The mean ¹³⁷Cs concentrations in the fruit-bodies were significantly different between the two plots, but no difference was observed in the soil ¹³⁷Cs concentration between the plots. Significant spatial autocorrelation was observed in the ¹³⁷Cs concentration in the organic layer for both sites, but no significant spatial autocorrelation was observed in the ¹³⁷Cs of fruit-bodies. Therefore, the variation in the ¹³⁷Cs concentrations of co-occurred B. hiratsukae was not explained by spatial bias or radioactivity in the below soil. In contrast, the exchangeable potassium concentration in the soil was negatively correlated with the ¹³⁷Cs in the fruit-bodies. Our results suggest that the ¹³⁷Cs absorption of wild mushrooms would be suppressed by the competitive effect of exchangeable potassium in the surrounding soils.

据报道，野生蘑菇中放射性铯（¹³⁷ Cs）的活性浓度根据物种，属或生态类型而变化。此外，浓度在同一区域内收集的同一物种之间会波动。因此，我们调查了野生蘑菇中¹³⁷ Cs的浓度是否会（1）在空间上有偏差，或者（2）受下面土壤中¹³⁷ Cs或可交换钾浓度的影响。我们在日本筑波的喜马拉雅雪松森林中设置了两个相距300 m的调查地块，其中 福岛核电站事故发生后，沉积了¹³⁷ Cs的30 kBq / m ²。从这些样地中，我们收集了同时发生的果体（用于产生孢子的真菌结构）牛肝菌（Boletus hiratsukae）是一种菌根物种，也来自下面的土壤。在两个样区之间，果体内的平均¹³⁷ Cs浓度存在显着差异，但在两个样区之间的土壤¹³⁷ Cs浓度中未观察到差异。在两个位置的有机层中，在¹³⁷ Cs浓度下均观察到显着的空间自相关，但在¹³⁷ Cs的果体中未观察到显着的空间自相关。因此，共同存在的B. hiratsukae的¹³⁷ Cs浓度的变化地下土壤中的空间偏倚或放射性无法解释。相反，土壤中可交换的钾浓度与果体内的¹³⁷ Cs呈负相关。我们的结果表明，野生蘑菇的¹³⁷ Cs吸收将被周围土壤中可交换钾的竞争作用所抑制。