High potential, but low actual, glycine uptake of dominant plant species in three Australian land-use types with intermediate N availability
Skip to main content
eScholarship
Open Access Publications from the University of California

High potential, but low actual, glycine uptake of dominant plant species in three Australian land-use types with intermediate N availability

  • Author(s): Kahmen, Ansgar
  • Livesley, Stephen J.
  • Arndt, Stefan K.
  • et al.
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 4 + 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.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Main Content
Current View