Effects of emergent aquatic plants on nitrogen transformation processes and related microorganisms in a constructed wetland in northern China
- 106 Downloads
Wetland plants affect ammonia-oxidation rate (AOR) and nitrogen-fixation rate (NFR), resulting in changes in plant-available nitrogen and wetland nitrogen-cycling. This study aims to investigate the underlying mechanisms and influencing factors associated with ammonium oxidation and nitrogen fixation in response to wetland-emergent aquatic plants.
A field experiment was conducted to study the response of activity, abundance, and community structure of ammonia-oxidizers and diazotrophs to three wetland-emergent aquatic plants in summer and autumn. The root exudates and soil physicochemical properties were determined due to their important role in rhizosphere interactions.
AOR and NFR were significantly higher in rhizosphere than in bulk soils. The increases of AOR and NFR in rhizosphere were significantly positively affected by oxidation-reduction potential, additionally, NFR was also significantly affected by sugar-containing root exudates. Furthermore, NFR strongly correlated with diazotroph abundance, whereas AOR was linearly correlated with ammonia-oxidizing archaea (AOA) activity and mostly determined by a specific AOA taxon.
Emergent plant rhizosphere exhibited strong positive effects on AOR and NFR by altering community structure and abundance of related microorganisms. Release of available oxygen and carbon in plant rhizospheres is vital for promoting ammonium oxidation and nitrogen fixation and might further mediate wetlands nitrogen-cycling.
KeywordsAmmonium oxidation Nitrogen fixation Aquatic plants Rhizosphere Root exudates
analysis of variance
dissolved organic carbon
high-performance liquid chromatography
polymerase chain reaction
quantitative real-time polymerase chain reaction
total organic carbon
Zhaoniu River Constructed Wetland
We thank Professor Yupeng Geng in Yunnan University and three anonymous referees for their valuable comments and suggestions on the manuscript. This study was supported by the “China Major Science and Technology Program for Water Pollution Control and Treatment” (No.2017ZX07101003), the “Natural Science Foundation of Shandong Province, China” (No. ZR2017MC013) and the “National Natural Science Foundation of China” (No. 41601333). We would like to thank Editage for English language editing.
- Bais HP, Weir TL, Perry LG, Gilroy S, Vivanco JM (2006) The role of root exudates in rhizosphere interactions with plants and other organisms. Annu Rev Plant Biol 57:233–266. https://doi.org/10.1146/annurev.arplant.57.032905.105159 CrossRefGoogle Scholar
- Capone D (1988) Benthic nitrogen fixation. In: Blackburn TH, Sorensen J (eds) Nitrogen cycling in coastal marine environments. Wiley, New YorkGoogle Scholar
- Gremion F, Chatzinotas A, Harms H (2003) Comparative 16S rDNA and 16S rRNA sequence analysis indicates that Actinobacteria might be a dominant part of the metabolically active bacteria in heavy metal-contaminated bulk and rhizosphere soil. Environ Microbiol 5:896–907. https://doi.org/10.1046/j.1462-2920.2003.00484.x CrossRefGoogle Scholar
- He J, Shen J, Zhang L, Zhu Y, Zheng Y, Xu M, Di H (2007) Quantitative analyses of the abundance and composition of ammonia-oxidizing bacteria and ammonia-oxidizing archaea of a Chinese upland red soil under long-term fertilization practices. Environ Microbiol 9:2364–2374. https://doi.org/10.1111/j.1462-2920.2007.01358.x CrossRefGoogle Scholar
- Huang J, Xu X, Wang M, Nie M, Qiu S, Wang Q, Quan Z, Xiao M, Li B (2016) Responses of soil nitrogen fixation to Spartina alterniflora invasion and nitrogen addition in a Chinese salt marsh. Sci Rep-UK 6. https://doi.org/10.1038/srep20384
- Liu G, Jiang N, Zhang L, Liu Z (1996) Soil physical and chemical analysis and description of soil profiles, vol. 24. China Standard Methods Press, Beijing, p 266Google Scholar
- Taylor AE, Vajrala N, Giguere AT, Gitelman AI, Arp DJ, Myrold DD, Bottomley PJ (2013) Use of aliphatic n-alkynes to discriminate soil nitrification activities of ammonia-oxidizing thaumarchaea and bacteria. Appl Environ Microbiol 79:6544–6551. https://doi.org/10.1128/AEM.01928-13 CrossRefGoogle Scholar