LAUSR

ABSTRACT To study the effects of inoculation with ectomycorrhizal fungi on the accumulation and distribution of radiocesium (137Cs) in different plant organs (leaves, stems and roots), we measured the uptake and internal distribution of 137Cs by ectomycorrhizal and non-ectomycorrhizal Quercus serrata seedlings in contaminated forest soil. Contamination was a result of the Fukushima Dai-ichi nuclear Power Plant accident. We also estimated the transfer factor (TF), photosynthetic rate and growth of Q. serrata seedlings during the study period, which lasted a full year. The seedlings were grown in plastic pots under field conditions. The soils used in this study had been contaminated with 7200 Bq kg−1 dm of 137Cs at Fukushima in 2011. The concentration of 137Cs in the plant organs varied between 148, 252 and 294 Bq kg−1 dm in the non-ectomycorrhizal treatment regime for stems, leaves and roots, respectively, and was 47, 69 and 219 Bq kg−1 dm in the ectomycorrhizal treatment regime. The TF was significantly lower (P < 0.01) in the ectomycorrhizal treatment regime EC, and apparent quantum yield (α) and maximum photosynthetic rate at light saturation (Pmax) was significantly higher (P < 0.01), although the growth parameters (stem diameter, height and dry mass) did not differ significantly.