The below-ground perspective of forest plants: soil provides mainly organic nitrogen for plants and mycorrhizal fungi
Article first published online: 4 MAY 2012
© 2012 The Authors. New Phytologist © 2012 New Phytologist Trust
Volume 195, Issue 2, pages 329–334, July 2012
How to Cite
Inselsbacher, E. and Näsholm, T. (2012), The below-ground perspective of forest plants: soil provides mainly organic nitrogen for plants and mycorrhizal fungi. New Phytologist, 195: 329–334. doi: 10.1111/j.1469-8137.2012.04169.x
- Issue published online: 15 JUN 2012
- Article first published online: 4 MAY 2012
- Received: 29 February 2012, Accepted: 6 April 2012
- amino acids;
- diffusive flux;
- plant nutrition;
- soil nutrients
- •Nitrogen (N) availability has a major impact on a wide range of biogeochemical processes in terrestrial ecosystems. Changes in N availability modify the capacity of plants to sequester carbon (C), but despite the crucial importance for our understanding of terrestrial ecosystems, the relative contribution of different N forms to plant N nutrition in the field is not known. Until now, reliably assessing the highly dynamic pool of plant-available N in soil microsites was virtually impossible, because of the lack of adequate sampling techniques.
- •For the first time we have applied a novel microdialysis technique for disturbance-free monitoring of diffusive fluxes of inorganic and organic N in 15 contrasting boreal forest soils in situ.
- •We found that amino acids accounted for 80% of the soil N supply, while ammonium and nitrate contributed only 10% each. In contrast to common soil extractions, microdialysis revealed that the majority of amino acids are available for plant and mycorrhizal uptake.
- •Our results suggest that the N supply of boreal forest soils is dominated by organic N as a major component of plant-available N and thus as a regulator of growth and C sequestration.