Ozone Susceptibility of Ten Azalea Cultivars as Related to Stomatal Frequency or Conductance1

Abstract

Abstract Ten cultivars of azalea (Rhododendron sp.) were exposed to 0.30 ± 0.05 ppm ozone (590 ±100 μg/m3) for 8 hours at various times during the summer. ‘Louise Gable,’ ‘Delaware Valley White’ and ‘Rose Greeley’ were significantly more susceptible than were ‘Stewartstonian,’ ‘Fedora,’ ‘Orange Beauty,’ ‘Hino-crimson,’ ‘Hershey Pink,’ ‘Rosebud,’ and ‘Springfield Crimson.’ Neither rate of gas exchange nor stomatal frequency was correlated with degree of visible injury induced by ozone.