Relations of fine-root morphology on 137Cs uptake by fourteen Brassica species

Fourteen Brassica species consisting of seven leafy vegetables and seven root vegetables were examined for 137Cs uptake differences in relation to their fine-root morphological characters. A pot experiment was conducted from November 2014 to February 2015 in a Phytroton using a contaminated soil of Fukushima prefecture. Leafy vegetables showed bigger root diameters, larger root surface area and larger root volume. Consequently, leafy vegetables had higher 137Cs uptake compared to root vegetables. Among the three fine-root parameters, only root surface area was observed as a significant contributing factor to higher 137Cs uptake in terms of transfer factor (TF, dry weight basis). Kakina exhibited higher 137Cs TF value (0.20) followed by Chinese cabbage (0.18) and mizuna (0.17). Lower TF values were observed in turnip (0.059), rutabaga (Kitanoshou) (0.062) and radish (Ha daikon) (0.064).