Growth and 137Cs uptake of four Brassica species influenced by inoculation with a plant growth-promoting rhizobacterium Bacillus pumilus in three contaminated farmlands in Fukushima prefecture, Japan

The effectiveness of the plant growth-promoting rhizobacterium Bacillus pumilus regarding growth promotion and radiocesium (Cs-137) uptake was evaluated in four Brassica species grown on different Cs-137 contaminated farmlands at Fukushima prefecture in Japan from June to August 2012. B. pumilus inoculation did not enhance growth in any of the plants, although it resulted in a significant increase of Cs-137 concentration and higher Cs-137 transfer from the soil to plants. The Brassica species exhibited different Cs-137 uptake abilities in the order Komatsuna > turnip > mustard > radish. TF values of Cs-137 ranged from 0.018 to 0.069 for all vegetables. Komatsuna possessed the largest root surface area and root volume, and showed a higher Cs-137 concentration in plant tissue and higher Cs-137 TF values (0.060) than the other vegetables. Higher Cs-137 transfer to plants was prominent in soil with a high amount of organic matter and an Al-vermiculite clay mineral type. (C) 2015 Elsevier B.V. All rights reserved.