© 1995 Heron Publishing—Victoria, Canada
Environmental control of ozone uptake in Larix decidua Mill.: a comparison between different altitudes
Gerhard Wieser and Wilhelm M. Havranek
Forstliche Bundesversuchsanstalt, Rennweg 1, A-6020 Innsbruck, Austria / Received June 6, 1994
Summary
We studied ozone (O3) uptake by European larch (Larix decidua Mill.) needles under ambient conditions at both a low and a high elevation site. At a given ambient O3 concentration, the rate of O3 uptake by needles was effectively controlled by stomatal conductance and, hence, by factors such as light, humidity and water
status, which control stomatal conductance. At both study sites, atmospheric water vapor pressure deficit (VPD) was the climatic
factor most closely correlated with ambient O3 concentration. Thus, when ambient O3 concentrations were highest, O3 flux into the needles tended to be restricted by narrowing of the stomata. Mitigation of potential O3 stress by stomatal closure was most marked at the low elevation site where both soil water stress and atmospheric VPD were
greater than at the high elevation site.
Keywords:
altitudinal gradient, larch, stomatal conductance.
