© 2003 Heron Publishing—Victoria, Canada
Biochemical acclimation patterns of Betula pendula and Pinus sylvestris seedlings to elevated carbon dioxide concentrations
Eija Juurola (1)
1. University of Helsinki, Department of Forest Ecology, P.O. Box 27, FIN-00014 University of Helsinki, Finland (Eija.Juurola@helsinki.fi) / Received March 1, 2002; accepted June 30, 2002; published online January 2, 2003
Summary
Acclimation of photosynthesis to increasing atmospheric carbon dioxide concentration ([CO2]; 350 to 2000 μmol mol–1) was followed in silver birch (Betula pendula Roth.) and Scots pine (Pinus sylvestris L.) seedlings for two years. Chlorophyll fluorescence and concentrations of Rubisco, chlorophyll, total soluble protein and
nitrogen were monitored together with steady-state gas exchange at three CO2 concentrations (ambient [CO2] (345 ± 20 μmol mol–1), the growth [CO2] and 1950 ± 55 μmol mol–1).
Rubisco and chlorophyll concentrations decreased in birch and Scots pine with increasing growth [CO2]. A nonlinear response was recorded for Rubisco and chlorophyll concentrations in birch, which was correlated with a significant
decrease in specific leaf area. Nitrogen concentration decreased in birch leaves, but was unchanged in Scots pine needles.
The species differed substantially in their steady-state CO2 exchange response to increasing growth [CO2]. The principal effect in birch was a significant nonlinear decrease in the steady-state gas exchange rate at the ambient
[CO2], whereas in Scots pine the main effect was a significant increase in the steady-state gas exchange rate at the growth [CO2].
Keywords:
chlorophyll, CO2 exchange, nitrogen, photosynthesis, Rubisco, silver birch, Scots pine.
