Growth, nitrogen uptake, and resource allocation in the two tripartite lichens Nephroma arcticum and Peltigera aphthosa during nitrogen stress
2002 (English)In: New Phytologist, ISSN 0028-646X, Vol. 153, no 2, 307-315 p.Article in journal (Refereed) Published
The lichens were irrigated with different N forms, enriched in 15N to assess N uptake, during 3 months in the field, with a total N dosage of 500 mg m−2. Nitrogen deprivation was induced by removing the nitrogen-fixing cephalodia.
The lichens took up 11–134 mg N m−2 of the added N, corresponding to 1–4% of their total thallus N. Uptake was 4 times higher for NH4+ than for NO3−, and the highest 15N concentrations were found in newly synthesized tissue. Both forms of N stress affected thallus expansion rates in both species.
It is concluded that the two lichens were able to maintain a balanced tissue N concentration despite large variations in N supply, and that assimilated N might be transported to growing apices. Alternatively, N assimilation from external sources might be greater in the margins than in the mature thallus. Thallus expansion was sensitive to N stress, apparently being tightly coupled to N assimilation.
Place, publisher, year, edition, pages
2002. Vol. 153, no 2, 307-315 p.
IdentifiersURN: urn:nbn:se:umu:diva-2400DOI: 10.1046/j.0028-646X.2001.00321.xOAI: oai:DiVA.org:umu-2400DiVA: diva2:140378