title: Stable cesium uptake and accumulation capacities of five plant species as influenced by bacterial inoculation and cesium distribution in the soil.
abstract: The effects of inoculation with Bacillus and Azospirillum strains on growth and cesium accumulation of five plant species, Komatsuna, Amaranth, sorghum, common millet and buckwheat, grown on cesium-spiked soil were assessed for potential use in cesium remediation. Pot experiments were performed using "artificially" Cs-contaminated soil. Three treatments were applied based on Cs location in the soil. For a soil height of 15 cm in the pots, Cs was added as follows: in the top five cm to imitate no ploughing condition; in the bottom five cm simulating inverted ploughing; and uniformly distributed Cs reproducing normal plowing. Generally, inoculation of Cs-exposed plants significantly enhanced growth and tolerance to this element. Transfer factor (ratio of Cs concentration in the plant tissues to that in surrounding soil) was strongly influenced by Cs distribution, with higher values in the top-Cs treatment. Within this treatment, inoculation of Komatsuna with Bacillus and Azospirillum strains resulted in the greatest transfer factors of 6.55 and 6.68, respectively. Cesium content in the shoots was high in the Azospirillum-inoculated Komatsuna, Amaranth, and buckwheat, i.e., 1,830, 1,220, and 1,030 µg per pot, respectively (five plants were grown in each pot). Therefore, inoculation of Komatsuna and Amaranth with the strains tested here could be effective in enhancing Cs accumulation. The decrease of Cs transfer under uniform- and bottom-Cs treatments would suggest that countermeasures aiming at decreasing the transfer of Cs could rely on ploughing practices.
authors.affiliation: Department of Biological Production Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-chou, Fuchu, Tokyo, 183-8509, Japan.
authors.forename: Salem
authors.initials: S
authors.lastname: Djedidi
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Kojima
authors.forename: Hiroko
authors.initials: H
authors.lastname: Yamaya
authors.forename: Naoko
authors.initials: N
authors.lastname: Ohkama-Ohtsu
authors.forename: Sonoko Dorothea
authors.initials: SD
authors.lastname: Bellingrath-Kimura
authors.forename: Izumi
authors.initials: I
authors.lastname: Watanabe
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yokoyama
mesh_terms: D016949:Azospirillum / Q000502:physiology*; D001407:Bacillus / Q000145:classification / Q000502:physiology*; D001673:Biodegradation, Environmental; D002586:Cesium / Q000378:metabolism*; D062406:Fukushima Nuclear Accident; D010944:Plants / Q000378:metabolism* / Q000382:microbiology*; D012989:Soil Pollutants / Q000378:metabolism*
chemical_list: D012989:Soil Pollutants; D002586:Cesium