Skip to main content
SLU publication database (SLUpub)
Research article - Peer-reviewed, 2019

The delta N-15 value of N-2 fixing actinorhizal plants and legumes grown with N-2 as the only nitrogen source

Gentili, Francesco G.; Huss-Danell, Kerstin


The aim of this study was to investigate the effects of different plant parts and the age of plants at harvest as well as N-2 fixing bacterial strains on the N concentration in symbiotic plant parts, especially on the delta N-15 signature of the actinorhizal plants and legumes. The N-15 natural abundance method was used. Two actinorhizal plants were studied: Alnus incana (L.) infected with the Frankia strains ArI3 or "lsF" (local source of Frankia) and Hippophae rhamnoides (L.) infected with the Frankia strains T1 or E15b. Two legume species were studied: Hedysarum coronarium (L.), infected with a soil suspension, and Robinia pseudoacacia (L.), infected with a crushed nodule suspension. It was particularly interesting that in A. incana, the two Frankia strains affected not only N concentration and delta N-15 signature of leaves and roots, but also had an impact on plant growth at first harvest. In Hippophae rhamnoides plants inoculated with the Frankia strains T1 and E15b, N concentrations and delta N-15 values did not differ at any harvest time. However, plants nodulated by the Frankia strain T1 showed a higher nitrogen fixation rate and higher plant dry matter at all harvesting times. Based on our results for the quantification of N-2 fixation with the "B" value, that is the delta N-15 value of the N-2 fixing plants relying only on N-2 fixation, plant parts, ages and strains should be carefully considered.


Actinorhizal plants; B value; Leguminous plant; N-15 natural abundance; delta N-15; N-2 fixation

Published in

2019, Volume: 79, number: 3, pages: 213-219
Publisher: SPRINGER

      SLU Authors

      • Huss-Danell, Kerstin

        • Department of Agricultural Research for Northern Sweden, Swedish University of Agricultural Sciences

      UKÄ Subject classification

      Soil Science

      Publication Identifiers


      Permanent link to this page (URI)