Plant and Soil

, Volume 285, Issue 1, pp 221–231

Significance of organic nitrogen acquisition for dominant plant species in an alpine meadow on the Tibet plateau, China

  • Xingliang Xu
  • Hua Ouyang
  • Yakov Kuzyakov
  • Andreas Richter
  • Wolfgang Wanek
ORIGINAL PAPER

DOI: 10.1007/s11104-006-9007-5

Cite this article as:
Xu, X., Ouyang, H., Kuzyakov, Y. et al. Plant Soil (2006) 285: 221. doi:10.1007/s11104-006-9007-5

Abstract

Though the potential of plants to take up organic N (e.g., amino acids) is well established, the true significance of organic N acquisition to plant N nutrition has not yet been quantified under field conditions. Here we demonstrate that organic N contributes significantly to the annual N uptake of three dominant plant species (Kobresia humilis, Saussurea superba and Stipa aliena) of alpine meadows on the Tibet Plateau, China. This was achieved by using double-labelled (14C and 15N) algae as a source for slow and continuous release of amino acids, and tracing both labels in the above- and below-ground plant biomass. Four months after addition of algae, between 0.5% and 2.6% of 14C and 5% and 14% of 15N from added algae were recovered in the plants, which translate into an uptake of organic N between 0.3 mg N m−2 and 1.5 mg N m−2. The calculated contribution of organic N to total N uptake was estimated to range between 21% and 35% for K. humilis, and between 13% and 21% for S. aliena and S. superba, respectively, implying that organic N uptake by grassland plants is quantitatively significant under field conditions in the studied alpine meadows. This finding has important ecological implications with regard to competition for organic N between microorganisms and plant roots.

Keywords

Organic N uptake14C15NAlpine grasslandN acquisitionSpirulina

Copyright information

© Springer Science+Business Media B.V. 2006

Authors and Affiliations

  • Xingliang Xu
    • 1
    • 2
  • Hua Ouyang
    • 1
  • Yakov Kuzyakov
    • 2
    • 4
  • Andreas Richter
    • 3
  • Wolfgang Wanek
    • 3
  1. 1.Institute of Geographical Sciences & Natural Resources ResearchThe Chinese Academy of SciencesBeijingPR China
  2. 2.Institute of Soil Science and Land EvaluationUniversity of HohenheimStuttgartGermany
  3. 3.Department of Chemical Ecology and Ecosystem ResearchVienna Ecology Centre University of ViennaWienAustria
  4. 4.Department of Agroecosystem ResearchUniversity of BayreuthD-95440 BayreuthGermany