© 2003 Heron Publishing—Victoria, Canada
Contrasting effects of elevated carbon dioxide concentration and temperature on Rubisco activity, chlorophyll fluorescence,
needle ultrastructure and secondary metabolites in conifer seedlings
Leena Sallas (1), Eeva-Maria Luomala (2), Jarkko Utriainen (1), Pirjo Kainulainen (1, 3) and Jarmo K. Holopainen (1, 3, 4)
1. Department of Ecology and Environmental Science, University of Kuopio, POB 1627, FIN-70211 Kuopio, Finland / 2. Finnish Forest Research Institute, Suonenjoki Research Station, FIN-77600 Suonenjoki, Finland / 3. Agricultural Research Center of Finland, Plant Protection, FIN-31600 Jokioinen, Finland / 4. Author to whom correspondence should be addressed (jarmo.holopainen@uku.fi) / Received March 25, 2002; accepted June 30, 2002; published online January 2, 2003
Summary
Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings were grown for 50 days in growth chambers in an ambient or twice ambient carbon dioxide concentration
([CO2]) at a day/night temperature of 19/12 °C or 23/16 °C. Although elevated [CO2] (EC) had only slight effects on the growth parameters measured, elevated temperature (ET) increased aboveground dry mass
of both species. Among treatments, biomass accumulation of both species was greatest in the combined EC + ET treatment. The
EC treatment induced thylakoid swelling and increased numbers of plastoglobuli observed in Scots pine needles. Although EC
had little effect on Rubisco protein or N concentration of needles, ET had a large effect on N-containing compounds and enhanced
N allocation from 1-year-old needles. Terpenoids were more responsive to EC and ET than total phenolics. Generally, terpene
concentrations were reduced by EC and increased by ET. Increased terpenoid concentrations in response to ET might be associated
with thermotolerance of photosynthesis. In Norway spruce, EC decreased total phenolic concentrations in needles, probably
as a result of increased growth. We conclude that, in seedlings of these boreal species, the effects of elevated [CO2] on the studied parameters were small compared with the effects of elevated temperature.
Keywords:
climate change, CO2 concentration, ecophysiology, growth, monoterpenes, Norway spruce, Picea abies, Pinus sylvestris, resin acids, Scots pine, soluble proteins, total phenolics.
