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- Title
High potential, but low actual, glycine uptake of dominant plant species in three Australian land-use types with intermediate N availability.
- Authors
Kahmen, Ansgar; Livesley, Stephen J.; Arndt, Stefan K.
- Abstract
The traditional view of the nitrogen (N) cycle has been challenged since the discovery that plants can compete with microbes for low molecular weight (LMW) organic N. Despite a number of studies that have shown LMW organic N uptake by plants, there remains a debate on the overall ecological relevance of LMW organic N uptake by plants across ecosystems with different N availabilities. We here report patterns of glycine N uptake by plants from three different Australian land-use types with intermediate N availability and low inherent glycine concentrations in the soil. Using 15N labeled tracers, we tested the potential of these plants to acquire glycine in ex-situ laboratory experiments and attempted to validate these results in the field by determining actual uptake of glycine by plants directly from the soil. We found in the ex-situ experiments that plants from all three land-use types were able to take up significant amounts of glycine. In contrast, glycine uptake directly from the soil was minimal in all three land-use types and 15N tracers were largely immobilized in the soil organic N pool. Our study confirms that the potential for LMW organic N uptake by plants is a widespread phenomenon. However, our in-situ experiments show that in the three land-use types tested here plants are inferior competitors for LMW organic N and rely on NH as their main N source. In contrast to several previous studies in arctic, alpine and even temperate ecosystems, our study suggests that in ecosystems with intermediate N availability, mineral N is the plants’ main N source, while LMW organic N is of less ecological relevance to plant N nutrition.
- Subjects
NITROGEN cycle; MOLECULAR weights; GLYCINE; AMINO acids; LAND use; STABLE isotopes; ISOTOPES; AMINO acid neurotransmitters; BIOGEOCHEMICAL cycles
- Publication
Plant & Soil, 2009, Vol 325, Issue 1/2, p109
- ISSN
0032-079X
- Publication type
Article
- DOI
10.1007/s11104-009-9960-x