Influence of potassium-solubilizing bacteria on the growth and radiocesium phyto-transfer of Brassica rapa L. var. perviridis grown in contaminated Fukushima soils. (October 2021)

• Record Type: Journal Article
• Authors: Rallos, Roland V.; Dicen, Gerald P.; Habibi, Safiullah; Salem, Djedidi; Ohkama-Ohtsu, Naoko; Yokoyama, Tadashi
• Is Part Of: Journal of environmental radioactivity. Volume 237(2021)
• Publication Date: 2021-10
• Subjects: 137Cs -- 16S rRNA -- Komatsuna -- Phytotransfer -- Potassium-solubilizing bacteria -- 137Cs contamination; Radioactivity -- Periodicals; Radiation, Background -- Periodicals; Radioecology -- Periodicals; Radioactive pollution -- Periodicals; Environmental Pollutants -- Periodicals; Radioactive Pollutants -- Periodicals; Radioactivity -- Periodicals; Radioécologie -- Périodiques; Pollution radioactive -- Périodiques; Fond de rayonnement -- Périodiques; 539.752
• DOI: 10.1016/j.jenvrad.2021.106682
• Languages: English
• ISSNs: 0265-931X

Abstract

Abstract: The supply of K, being the chemical analog of Cs, affects the phytotransfer of radiocesium such as 137 Cs from contaminated soils and its accumulation in plant tissues. Since K and Cs have high affinity to the same clay particle surfaces, the presence of potassium-solubilizing bacteria (KSB) could increase the availability of not only K + in the rhizosphere but also of radiocesium. In this study, we obtained five KSB isolates with the highest solubilization capacities from soybean rhizosphere on modified Aleksandrov medium containing sericite as K source. Based on biochemical and 16S rRNA gene sequence analysis, we identified the bacteria as Bacillus aryabhattai MG774424, Pseudomonas umsongensis MG774425, P. frederiksbergensis MG774426, Burkholderia sabiae MG774427, and P. mandelii MG774428. We evaluated the KSB isolates based on plant growth promotion and 137 Cs accumulation in komatsuna ( Brassica rapa L. var. Perviridis ) grown in three soils collected from Miyanoiri, Takanishi, and Ota contaminated by 137 Cs from the Fukushima accident. Inoculation with KSB showed beneficial effects on plant growth and increased the overall plant biomass production (~40%). On the average, KSB inoculation resulted in the removal of 0.07 ± 0.04% of 137 Cs from the soil, more than twice the control. But similar to the effect of KSB inoculation on komatsuna biomass production, different KSBs performed variably and exhibited site-specific responses independent of their K-solubilizing capacities, with higher 137 Cs phyto-transfer in roots than in shoots. In terms of root transfer factor (TF), values were highest in komatsuna plants grown in Miyanoiri and Ota soils inoculated with P. frederiksbergensis and Burkholderia sabiae, while they were highest in Takanishi soils inoculated with Bacillus aryabhattai and P. umsongensis. These TF values were also much higher than previously reported values for komatsuna grown in 137 Cs-contaminated Fukushima soils inoculated with other rhizobacteria. Thus, KSB inoculation significantly enhance not only the growth of komatsuna but 137 Cs uptake. Highlights: Potassium-solubilizing bacteria (KSB) enhance plant growth and radiocesium uptake. High radiocesium concentration was observed in komatsuna roots than in shoots. KSB inoculation resulted in high radiocesium removal from contaminated soil.