Organic nitrogen enhances nitrogen nutrition and early growth of Pinus sylvestris seedlings.

Journal Article (Journal Article)

Boreal trees are capable of taking up organic nitrogen (N) as effectively as inorganic N. Depending on the abundance of soil N forms, plants may adjust physiological and morphological traits to optimize N uptake. However, the link between these traits and N uptake in response to soil N sources is poorly understood. We examined Pinus sylvestris L. seedlings' biomass growth and allocation, transpiration and N uptake in response to additions of organic N (the amino acid arginine) or inorganic N (ammonium nitrate). We also monitored in situ soil N fluxes in the pots following an addition of N, using a microdialysis system. Supplying organic N resulted in a stable soil N flux, whereas the inorganic N resulted in a sharp increase of nitrate flux followed by a rapid decline, demonstrating a fluctuating N supply and a risk for loss of nitrate from the growth medium. Seedlings supplied with organic N achieved a greater biomass with a higher N content, thus reaching a higher N recovery compared with those supplied inorganic N. In spite of a higher N concentration in organic N seedlings, root-to-shoot ratio and transpiration per unit leaf area were similar to those of inorganic N seedlings. We conclude that enhanced seedlings' nutrition and growth under the organic N source may be attributed to a stable supply of N, owing to a strong retention rate in the soil medium.

Full Text

Duke Authors

Cited Authors

  • Lim, H; Jämtgård, S; Oren, R; Gruffman, L; Kunz, S; Näsholm, T

Published Date

  • March 2022

Published In

Volume / Issue

  • 42 / 3

Start / End Page

  • 513 - 522

PubMed ID

  • 34580709

Pubmed Central ID

  • PMC8919414

Electronic International Standard Serial Number (EISSN)

  • 1758-4469

International Standard Serial Number (ISSN)

  • 0829-318X

Digital Object Identifier (DOI)

  • 10.1093/treephys/tpab127

Language

  • eng