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| Isolation of heavy metal resistant and plant growth promoting Bacillus strains and effects on cadmium removal by Typha angustifolia |
| Received:May 04, 2017 |
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| KeyWord:Bacillus species;Typha angustifolia;heavy metal contaminated waters;remediation;cadmium |
| Author Name | Affiliation | E-mail | | PANG Hai-dong | Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | HE Zhuo | Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | YAN Chuan-ming | Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | SHENG Xia-fang | Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China | | | HE Lin-yan | Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China | helyan0794@njau.edu.cn |
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| Abstract: |
| Metal resistant bacteria provide an effective way to enhance heavy metal removal rates of wetland phytoremediation systems. In this work, heavy metal resistant rhizobacteria and endophytic bacteria were isolated from plants growing in the waste mine wetland in Nanjing, Jiangsu, China. The effects of the bacteria on plant growth and cadmium removal by the narrow-leaved cattail(Typha angustifolia L.) under excessive cadmium exposure were investigated. The results indicated that the eight metal resistant Bacillus strains isolated from the aquatic plants showed a variety of growth promoting features including solubilizing phosphate and producing indole acetic acid(IAA), siderophores, polysaccharides, and amylase. The isolates showed resistance to Cd, Pb, Cu, and Zn and tolerance to acids, alkalis, and salts. The growth of T.angustifolia was greatly promoted and the content of Cd in T.angustifolia increased after inoculation of the Bacillus strains into a Cd2+-containing solution. The dry weights of the root and aboveground tissues of T.angustifolia inoculated with Bacillus megaterium P24 and P37 were significantly increased by 40.0%~46.4%, compared with the control. Besides, the Cd content(31.1%) and total Cd uptake(63.5%) in the aboveground tissue increased when inoculated with Bacillus amyloliquefaciens P29. The highest Cd removal rate was 79.5%, after inoculation with B. megaterium P24. The results suggest that the metal resistant B.amyloliquefaciens P29 and B. megaterium P24 and P37 could be used as effective inoculants for improved phytoremediation in metal polluted waters. |
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