Borken, W; Horn, MA; Geimer, S; Bahamonde Aguilar, NA; Knorr, KH: Associative nitrogen fixation in nodules of the conifer Lepidothamnus fonkii (Podocarpaceae) inhabiting ombrotorphic bogs in soutern Patagonia, Scientific Reports, 6:39072 (2016), doi:10.1038/srep39072
Abstract:
Biological N2 fixation (BNF) in the rhizosphere of Podocarpaceae is currently attributed to unspecific diazotrophs with negligible impact on N acquisition. Here, we report specific and high associative BNF in dead cells of root nodules of Lepidothamnus fonkii distributed in ombrotrophic peatlands of Patagonia. BNF of nodulated roots, intact plants of L. fonkii and rhizospheric peat was assessed by 15N2 and acetylene reduction. Diazotrophs were identified by electron microscopy, analysis of nitrogenase encoding genes (nifH) and transcripts, and 16S rRNA. Nitrogenase encoding nifH transcripts from root nodules point to Beijerinckiaceae (Rhizobiales), known as free-living diazotrophs. Electron microscopy and 16S rRNA analysis likewise identified active Beijerinckiaceae in outer dead cells of root nodules. NifH transcripts from the rhizopshere peat revealed diverse active diazotrophs including Beijerinckiaceae. Both methods revealed high activity of nitrogenase rates in cut roots of L. fonkii (2.5 μmol N g−1 d.w. d−1 based on 15N2 assay; 2.4 μmol C2H4 g−1 d.w. d−1 based on acetylene reduction assay). The data suggest that (i) nodules recruit diazotrophic Beijerinckiaceae from peat, (ii) dead nodule cells provide an exclusive habitat for Beijerinckiaceae, and (iii) BNF in L. fonkii is one potent pathway to overcome N deficiency in ombrotrophic peatlands of Patagonia.
Upcoming ...

Th. 2022-12-08 now
Interviews Head of EBG
BayCEER Colloquium:
Th. 2022-12-08 now
Microbial-mineral interactions: Formation of pyrite and implications for biosignature and environmental research
Th. 2022-12-15
Living on the ice edge: insights into the environmental, climatic, and human history of the Ethiopian highlands
Th. 2023-01-12
Challenges in Soil Hydrological Modeling -- The Devil is in the Details ...
Ecological-Botanical Garden:
Su. 2023-01-01
Führung | Startklar! Bäume und ihre Knospen
Weather research site
Luftdruck (356m): 965.7 hPa
Lufttemperatur: 0.0 °C
Niederschlag: 0.7 mm/24h
Sonnenschein: <1 h/d

...more
Globalstrahlung: -1 W/m²
Lufttemperatur: -2.9 °C
Niederschlag: 2.1 mm/24h
Wind (Höhe 32m): 3.5 km/h

...more
This site makes use of cookies More information