Photosynthetic performance in Sphagnum transplanted along a latitudinal nitrogen deposition gradient
2009 (English)In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 159, no 4, 705-715 p.Article in journal (Refereed) Published
Increased N deposition in Europe has affected mire ecosystems. However, knowledge on the physiological responses is poor. We measured photosynthetic responses to increasing N deposition in two peatmoss species (Sphagnum balticum and Sphagnum fuscum) from a 3-year, north-south transplant experiment in northern Europe, covering a latitudinal N deposition gradient ranging from 0.28 g N m(-2) year(-1) in the north, to 1.49 g N m(-2) year(-1) in the south. The maximum photosynthetic rate (NPmax) increased southwards, and was mainly explained by tissue N concentration, secondly by allocation of N to the photosynthesis, and to a lesser degree by modified photosystem II activity (variable fluorescence/maximum fluorescence yield). Although climatic factors may have contributed, these results were most likely attributable to an increase in N deposition southwards. For S. fuscum, photosynthetic rate continued to increase up to a deposition level of 1.49 g N m(-2) year(-1), but for S. balticum it seemed to level out at 1.14 g N m(-2) year(-1). The results for S. balticum suggested that transplants from different origin (with low or intermediate N deposition) respond differently to high N deposition. This indicates that Sphagnum species may be able to adapt or physiologically adjust to high N deposition. Our results also suggest that S. balticum might be more sensitive to N deposition than S. fuscum. Surprisingly, NPmax was not (S. balticum), or only weakly (S. fuscum) correlated with biomass production, indicating that production is to a great extent is governed by factors other than the photosynthetic capacity.
Place, publisher, year, edition, pages
2009. Vol. 159, no 4, 705-715 p.
Chlorophyll fluorescence, Chlorophyll, Carbon dioxide exchange, Photosynthesis, Peatlands
IdentifiersURN: urn:nbn:se:uu:diva-120352DOI: 10.1007/s00442-008-1261-1ISI: 000264103800003OAI: oai:DiVA.org:uu-120352DiVA: diva2:303190