Effects of ozone on morpho-anatomy and physiology of Hedera helix

Chronic (60 ppb, 30 days, 5 h/d) and acute (200 ppb, 5 h) treatments with ozone were performed on ivy plants. Photosynthetic pigments decreased following the treatments, especially the chronic one. The fatty acids composition of cuticle was alterated. The activity of glyoxalase I and II increased significantly following the acute treatment. Both old and recently expanded leaves showed an increase in diffusion resistance and a reduction of the CO2 assimilatory activity, which was ascribed to stomatal contrains. The ecological implications of these alterations are discussed.