Figure 2.

Ozone uptake (black bars) by leaves of two plant species that do not emit isoprenoids, tobacco and birch, by a species emitting monoterpenes, holm oak, and by two species emitting isoprene, common reed and white poplar. The ozone uptake was also measured in leaves of tobacco and birch fumigated with 3 μL L⁻¹ of exogenous isoprene (white bar), and in leaves of holm oak, reed, and white poplar in which isoprenoid emission was previously inhibited by fosmidomycin (30 μm) feeding for 60 min (gray bars). Measurements were made on leaves showing the same stomatal conductance (0.1 mol m⁻² s⁻¹) and at the same environmental conditions (light intensity, 1,000 μmol m⁻² s⁻¹; leaf temperature, 30°C; relative humidity, 40%; and vapor pressure difference between leaf and air, 15 mbar). Measurements were repeated on five different leaves per species. Means and ses are shown, and means are separated by ANOVA using a multiple range test. Means significantly different are separated by different letters (P = 0.01, single letter; P = 0.05, double letters).