© 1995 Heron Publishing—Victoria, Canada
Effects of ozone on growth and gas exchange of Eucalyptus globulus seedlings
Mark Pearson
Division of Biological Sciences, Institute of Environmental and Biological Sciences, Lancaster University, Lancaster LA1 4YQ,
U.K. / Received October 12, 1993
Summary
To study the effects of a low concentration of ozone on growth and gas exchange in Eucalyptus globulus Labill. seedlings, ozone was applied for 37 days at a concentration of 50 ppb for 7 h daily under conditions of low light
(250 µmol m–2 s–1 (PAR)) and controlled temperature (20 °C). The seedlings exhibited extreme sensitivity to ozone. The ozone treatment reduced
total plant biomass but had no effect on the partitioning of assimilate. Photosynthesis, stomatal conductance and internal
CO2 concentration were all reduced by ozone. The decline in photosynthesis was partly the result of direct effects of ozone on
the stomata.
Keywords:
air pollution, biomass, stomata, stomatal conductance.
