Pedosphere 24(4): 553--562, 2014
ISSN 1002-0160/CN 32-1315/P
©2014 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Microbial biomass and PLFA profile changes in rhizosphere of pakchoi (Brassica chinensis L.) as affected by external cadmium loading |
SHENTU Jia-Li1,2 , HE Zhen-Li3,4, ZENG Yan-Yan1,2, HE Shan-Ying1,2, DU Shao-Ting1,2 and SHEN Dong-Sheng1,2 |
1College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012 (China)
2Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling, Zhejiang Gongshang University, Hangzhou 310012 (China)
3Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resources Science, Zhejiang University, Hangzhou 310029 (China)
4Institute of Food and Agricultural Science, Indian River Research and Education Center, University of Florida, Fort Pierce, FL 34945 (USA) |
| ABSTRACT |
| The effects of root activity on microbial response to cadmium (Cd) loading in the rhizosphere are not well understood. A pot experiment in greenhouse was conducted to investigate the effects of low Cd loading and root activity on microbial biomass and community structure in the rhizosphere of pakchoi (Brassica chinensis L.) on silty clay loam and silt loamy soil. Cd was added into soil as Cd(NO3)2 to reach concentrations ranging from 0.00 to 7.00 mg kg-1. The microbial biomass carbon (MBC) and community structure were affected by Cd concentration, root activity, and soil type. Lower Cd loading rates (< 1.00 mg kg-1) stimulated the growth of pakchoi and microorganisms, but higher Cd concentrations inhibited the growth of microorganisms. The content of phospholipid fatty acids (PLFAs) was sensitive to increased Cd levels. MBC was linearly correlated with the total PLFAs. The content of general PLFAs in the fungi was positively correlated with the available Cd in the soil, whereas those in the bacteria and actinomycetes were negatively correlated with the available Cd in the soil. These results indicated that fungi were more resistant to Cd stress than bacteria or actinomycetes, and the latter was the most sensitive to Cd stress. Microbial biomass was more abundant in the rhizosphere than in the bulk soil. Root activity enhanced the growth of microorganisms and stabilized the microbial community structure in the rhizosphere. PLFA analysis was proven to be sensitive in detecting changes in the soil microbial community in response to Cd stress and root activity. |
| Key Words: acidic soils, metal bioavailability, microbial community, microorganism, root activity |
| Citation: Shentu, J. L., He, Z. L., Zeng, Y. Y., He, S. Y., Du, S. T. and Shen, D. S. 2014. Microbial biomass and PLFA profile changes in rhizosphere of pakchoi (Brassica chinensis L.) as affected by external cadmium loading. Pedosphere. 24(4): 553-562. |
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