title: Seasonal variation of phenol/benzoate-degrading iron-reducing bacteria in irrigated tropical paddy soils as affected by some management practices.
abstract: The study provides the first evidence of the presence and abundance of bacterial population that coupled ferric iron reduction to aromatic compounds degradation in tropical irrigated paddy soils in the Philippines. Culturable phenol/benzoate degrading iron-reducing bacteria was enumerated by the most probable number (MPN) counts using phenol or benzoate as sole carbon source, and ferric oxide [Fe(OH)(3)] as the sole electron acceptor. Population density of phenol degrading iron-reducing bacteria (P-IRB) in irrigated paddy soil ranged from 10(2) to 10(8)g(-1) dry soil, and increased with the progressive rice growth in rice cropping seasons; the study also revealed a significant rhizosphere effect on population of P-IRB. However, high enumeration of benzoate degrading iron-reducing bacteria (B-IRB) was obtained in all the tested soil samples averaging at 1.2 x 10(6)g(-1) dry soil, and did not fluctuate significantly over the rice cropping seasons. Statistical data showed that less cropping density with aerated fallow and high nitrogen rate favored the population growth of P-IRB. However, results showed that population size of B-IRB was relatively insensitive to the effect of either seasonal or extrinsic factors tested in this study.
authors.affiliation: Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084, China. luwenjing@mail.tsinghua.edu.cn
authors.forename: Wen Jing
authors.initials: WJ
authors.lastname: Lu
authors.forename: Hong Tao
authors.initials: HT
authors.lastname: Wang
authors.forename: Chang Yong
authors.initials: CY
authors.lastname: Huang
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Reichardt
mesh_terms: D000383:Agriculture / Q000379:methods*; D001419:Bacteria / Q000145:classification / Q000187:drug effects / Q000378:metabolism*; D001565:Benzoates / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003470:Culture Media; D007501:Iron / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism / Q000494:pharmacology; D012275:Oryza / Q000254:growth & development; D010084:Oxidation-Reduction; D010575:Pesticides / Q000633:toxicity; D019800:Phenol / Q000378:metabolism*; D027343:Rhizome / Q000254:growth & development / Q000382:microbiology; D012621:Seasons; D012988:Soil Microbiology; D014329:Tropical Climate
chemical_list: D001565:Benzoates; D003470:Culture Media; D010575:Pesticides; D019800:Phenol; D007501:Iron; D009584:Nitrogen