Phosphorus, nitrogen and their interactions affect N-2 fixation, N isotope fractionation and N partitioning in Hippophae rhamnoides
2006 (English)In: Symbiosis, ISSN 0334-5114, E-ISSN 1878-7665, Vol. 41, no 1, 39-45 p.Article in journal (Refereed) Published
The interactive effects of varying phosphorus and nitrogen supplies on N-2 fixation, N isotope fractionation during N uptake, and N partitioning among plant parts were studied in the actinorhizal plant Hippophae rhamnoides L. (sea buckthorn). Plants were grown for six weeks after inoculation with the N-2-fixing actinomycete Frankia and differences in N accumulation were used to quantify N-2 fixation. N-15 natural abundance was analysed to study N isotope fractionation in specific plant parts in plants receiving different levels of N and P. Furthermore, the root system was split to study N isotope fractionation in roots supplied with different levels of N and P. Phosphorus stimulated N-2 fixation by direct effects on nodule dry matter and nodule function, rather than indirectly via plant growth. Phosphorus also stimulated N uptake from solution and influenced N isotope fractionation during N uptake. The inclusion of N-15 natural abundance analyses made it possible to detect P effects on N uptake, fractionation and N-2 fixation even though the plants used both N-2 fixation and combined N as N sources.
Place, publisher, year, edition, pages
2006. Vol. 41, no 1, 39-45 p.
IdentifiersURN: urn:nbn:se:umu:diva-26158OAI: oai:DiVA.org:umu-26158DiVA: diva2:240310