title: Soil enzymatic activities and microbial community structure with different application rates of Cd and Pb.
abstract: This study focused on the changes of soil microbial diversity and potential inhibitory effects of heavy metals on soil enzymatic activities at different application rates of Cd and/or Pb. The soil used for experiments was collected from Beijing and classified as endoaquepts. Pots containing 500 g of the soil with different Cd and/or Pb application rates were incubated for a period of 0, 2, 9, 12 weeks in a glasshouse and the soil samples were analyzed for individual enzymes, including catalase, alkaline phosphatase and dehydrogenase, and the changes of microbial community structure. Results showed that heavy metals slightly inhibited the enzymatic activities in all the samples spiked with heavy metals. The extent of inhibition increased significantly with increasing level of heavy metals, and varied with the incubation periods. The soil bacterial community structure, as determined by polymerase chain reaction-denaturing gradient gel electrophoresis techniques, was different in the contaminated samples as compared to the control. The highest community change was observed in the samples amended with high level of Cd. Positive correlations were observed among the three enzymatic activities, but negative correlations were found between the amounts of the heavy metals and the enzymatic activities.
authors.affiliation: Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. sardar.khan2008@yahoo.com
authors.forename: Sardar
authors.initials: S
authors.lastname: Khan
authors.forename: Qing
authors.initials: Q
authors.lastname: Cao
authors.forename: Abd El-Latif
authors.initials: Ael-L
authors.lastname: Hesham
authors.forename: Yue
authors.initials: Y
authors.lastname: Xia
authors.forename: Ji-Zheng
authors.initials: JZ
authors.lastname: He
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001419:Bacteria / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D002104:Cadmium / Q000633:toxicity*; D002374:Catalase / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D007854:Lead / Q000633:toxicity*; D010088:Oxidoreductases / Q000378:metabolism; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000633:toxicity*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D010088:Oxidoreductases; D002374:Catalase; D000469:Alkaline Phosphatase