Nitrogen and carbon isotope variability in the green-algal lichen Xanthoria parietina and their implications on mycobiont–photobiont interactions
Article first published online: 8 NOV 2012
© 2012 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Ecology and Evolution
Volume 2, Issue 12, pages 3132–3144, December 2012
How to Cite
Ecology and Evolution 2012; 2(12): 3132–3144
- Issue published online: 13 DEC 2012
- Article first published online: 8 NOV 2012
- Manuscript Accepted: 3 OCT 2012
- Manuscript Revised: 2 OCT 2012
- Manuscript Received: 12 SEP 2012
- GeoBio-Center at the LMU Munich
- Lichen symbiosis;
- stable isotope;
- Xanthoria parietina ;
Stable isotope patterns in lichens are known to vary largely, but effects of substrate on carbon and nitrogen stable isotope signatures of lichens were previously not investigated systematically. N and C contents and stable isotope (δ15N, δ13C) patterns have been measured in 92 lichen specimens of Xanthoria parietina from southern Bavaria growing on different substrates (bark and stone). Photobiont and mycobiont were isolated from selected populations and isotopically analyzed. Molecular investigations of the internal transcribed spacer of the nuclear ribosomal DNA (ITS nrDNA) region have been conducted on a subset of the specimens of X. parietina. Phylogenetic analysis showed no correlation between the symbionts X. parietina and Trebouxia decolorans and the substrate, isotope composition, or geographic origin. Instead specimens grown on organic substrate significantly differ in isotope values from those on minerogenic substrate. This study documents that the lichens growing on bark use additional or different N sources than the lichens growing on stone. δ15N variation of X. parietina apparently is controlled predominantly by the mass fraction of the mycobiont and its nitrogen isotope composition. In contrast with mycobionts, photobionts of X. parietina are much more 15N-depleted and show less isotopic variability than mycobionts, probably indicating a mycobiont-independent nitrogen acquisition by uptake of atmospheric ammonia.