Evaluation of the possibility to use the plant–microbe interaction to stimulate radioactive 137Cs accumulation by plants in a contaminated farm field in Fukushima, Japan

• Published in: Journal of plant research 2015-01, Vol.128 (1), p.147-159
• Main Authors: Djedidi, Salem, Terasaki, Akimi, Aung, Han Phyo, Kojima, Katsuhiro, Yamaya, Hiroko, Ohkama-Ohtsu, Naoko, Bellingrath-Kimura, Sonoko Dorothea, Meunchang, Phatchayaphon, Yokoyama, Tadashi
• Format: Article
• Language: English
• Subjects: aerial parts; agricultural land; Agriculture; Azospirillum; Azospirillum - physiology; Bacillus - physiology; Biomass; biomass production; Biomedical and Life Sciences; Brassica juncea; Brassica rapa subsp. nipposinica var. perviridis; buckwheat; Cesium Radioisotopes - analysis; crops; cultivars; farms; field experimentation; Fukushima Nuclear Accident; Geography; Japan; Life Sciences; Plant Biochemistry; Plant Ecology; Plant Physiology; Plant Sciences; Plants - microbiology; plowing; Radiation Monitoring; Regular Paper; soil; Soil - chemistry; Soil Pollutants, Radioactive - analysis
• ISSN: 0918-9440; 1618-0860
• DOI: 10.1007/s10265-014-0678-3

Field experiments in a contaminated farmland in Nihonmatsu city, Fukushima were conducted to assess the effectiveness of the plant–microbe interaction on removal of radiocesium. Before plowing, 93.3 % of radiocesium was found in the top 5 cm layer (5,718 Bq kg DW⁻¹). After plowing, Cs radioactivity in the 0–15 cm layer ranged from 2,037 to 3,277 Bq kg DW⁻¹. Based on sequential extraction, the percentage of available radiocesium (water soluble + exchangeable) was fewer than 10 % of the total radioactive Cs. The transfer of¹³⁷Cs was investigated in three agricultural crops; komatsuna (four cultivars), Indian mustard and buckwheat, inoculated with a Bacillus or an Azospirillum strains. Except for komatsuna Nikko and Indian mustard, inoculation with both strains resulted in an increase of biomass production by the tested plants. The highest¹³⁷Cs radioactivity concentration in above-ground parts was found in Bacillus-inoculated komatsuna Nikko (121 Bq kg DW⁻¹), accompanied with the highest¹³⁷Cs TF (0.092). Furthermore, komatsuna Nikko-Bacillus and Indian mustard-Azospirillum associations gave the highest¹³⁷Cs removal, 131.5 and 113.8 Bq m⁻², respectively. Despite the beneficial effect of inoculation, concentrations of¹³⁷Cs and its transfer to the tested plants were not very high; consequently, removal of¹³⁷Cs from soil would be very slow.