Plant and Soil

, Volume 176, Issue 1, pp 107–116

Interactions of elevated CO2, NH3 and O3 on mycorrhizal infection, gas exchange and N metabolism in saplings of Scots pine

  • Marta Pérez-Soba
  • Thomas A Dueck
  • Gigliola Puppi
  • Pieter J. C. Kuiper
Research Article

DOI: 10.1007/BF00017681

Cite this article as:
Pérez-Soba, M., Dueck, T.A., Puppi, G. et al. Plant Soil (1995) 176: 107. doi:10.1007/BF00017681


Four-year-old saplings of Scots pine (Pinus sylvestris) (L.) were exposed for 11 weeks in controlled-environment chambers to charcoad-filtered air, or to charcoal-filtered air supplemented with NH3 (40 μg m−3), O3 (110 μg m−3 during day/ 40 μg m−3 during night) or NH3+O3. All treatments were carried out at ambient (259 μL L−1) and at elevated CO2 concentration (700 μL L−1). Total tree biomass, mycorrhizal infection, net CO2 assimilation (Pn), stomatal conductance (gs), transpiration of the shoots and NH3 metabolization of the needles were measured. In ambient CO2 (1) gaseous NH3 decreased mycorrhizal infection, without significantly affecting tree biomass or N concentration and it enhanced the activity of glutamine synthetase (GS) and glutamate dehydrogenase (GDH) in one-year-old needles; (2) ozone decreased mycorrhizal infection and the acitivity of GS in the needles, while it increased the activity og GDH; (3) exposure to NH3+O3 lessened the effects of single exposures to NH3 and O3 on reduction of mycorrhizal infection and on increase in GDH activity. Similar lessing effects on mycorrhizal infection as observed in trees exposed to NH3+O3 at ambient CO2, were measured in trees exposed to NH3+O3 at elevated CO2. Exposure to elevated CO2 without pollutants did not significantly affect any of the parameters studied, except for a decrease in the concentration of soluble proteins in the needles. Elevated CO2 _NH3 strongly decreased root branching and mycorrhizal infection and temporarily stimulated Pn and gs. The exposure to elevated CO2+NH3+O3 also transiently stimulated Pn. The possible mechanisms underlying and integrating these effects are discussed. Elevated CO2 clearly did not alleviate the negative effects of NH3 and O3 mycoorhiral infection. The significant reduction of mycorrhizal infection after exposure to NH3 or O3, observed before significant changes in gas exchange or growth occurred, suggest the use of mycorrhizal infection as an early indicator for NH3 and O3 induced stress.

Key words

ammoniaelevated carbon dioxidegas exchangemycorrhizanitrogen metabolismozoneScots pine



dry weight


filtered air


filtered air at ambient CO2


filtered air at elevated CO2


fresh weight


glutamate dehydrogenase


glutamine synthetase


stomatal conductance


net CO2 assimilation


root weight ratio


specific root length

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • Marta Pérez-Soba
    • 1
  • Thomas A Dueck
    • 1
  • Gigliola Puppi
    • 2
  • Pieter J. C. Kuiper
    • 3
  1. 1.Department of Crop and Weed ScienceResearch Institute for Agrobiology and Soil Fertiligy (AB-DLO)WageningenThe Netherlands
  2. 2.Department of Plant BiologyUniversity of RomeRomeItaly
  3. 3.Department of Plant BiologyUniversity of GroningenHaren (Gn)The Netherlands