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Trees

, Volume 14, Issue 8, pp 475–484 | Cite as

Biomass allocation, needle structural characteristics and nutrient composition in Scots pine seedlings exposed to elevated CO2 and O3 concentrations

  • Jarkko Utriainen
  • Sari Janhunen
  • Heljä-Sisko Helmisaari
  • Toini Holopainen
Original Article

Abstract

Three-year-old Scots pine (Pinus sylvestris L.) seedlings were exposed to ambient or elevated ozone (O3) (1.5×ambient) and carbon dioxide (CO2) (590 µmol mol–1) concentrations during two growing seasons in open-top field chambers (OTCs). Five different treatments were applied in the chambers: filtered air, ambient air, elevated O3, elevated CO2, and elevated O3 and CO2 combined. Ambient plots outside the OTCs were also included, but the chamber ambient was used as a control in O3 and CO2 treatments due to a significant chamber effect. Increases in yellowing and chlorotic mottling of previous-year (C+1) needles and in the amount of cytoplasmic ribosomes and electron density of the chloroplast stroma in current-year (C) and C+1 needle mesophyll cells were observed in elevated O3 at both CO2 concentrations. Elevated O3 alone caused a non-significant 10.9% decrease in plant total dry mass and a significant decrease in manganese (Mn) content of C needles. CO2 enrichment caused a significant increase in needle cross-sectional width after the first year of exposure, and an accumulation of starch and slight curling and swelling of the chloroplast thylakoids in the mesophyll tissue of C needles after the second year of exposure. Calcium and Mn contents were increased and copper and nitrogen contents were decreased, significantly, in CO2-exposed needles. A non-significant 19.1% increase in plant total dry mass was measured in elevated CO2 alone, whereas a 14.8% reduction in total dry mass, together with a significant reduction in current-year main shoot length, was found in the combined treatment. Overall, in spite of decreases in O3-induced visible injuries by CO2, elevated CO2 levels were not able to counteract the impact of O3 in this experiment.

Scots pine Carbon dioxide Ozone Growth Needle structure 

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Copyright information

© Springer-Verlag 2000

Authors and Affiliations

  • Jarkko Utriainen
    • 1
  • Sari Janhunen
    • 1
  • Heljä-Sisko Helmisaari
    • 2
  • Toini Holopainen
    • 1
  1. 1.Department of Ecology and Environmental Science, University of Kuopio, PO Box 1627, FIN-70211 KuopioFinland
  2. 2.Department of Soil Science, Finnish Forest Research Institute, PO Box 18, FIN-01301 VantaaFinland

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