Abstract

Tropospheric ozone concentration has been rising in the last decades, due to industrial and other human activities. For plants, ozone constitutes one of the most damaging air pollutants. Main effects of ozone on forest species are reviewed: visible symptoms caused by acute exposure at the anatomical, structural and metabolic level, and the long run effects on growth and development derived from chronic exposure. Particular attention is given to photosynthesis and the effects on stomatal functioning, as major ozone injuries are inflicted to the plant after entering through the stomata. Plant detoxification capacity, carbohydrate allocation, growth and development are also revised, as well as the effects at the ecosystem level, defence mechanisms of plants against ozone, and their sensitivity and tolerance. The rising problem of tropospheric ozone contamination should awaken the international awareness and measures should be taken to control ozone atmospheric levels considering their transnational implications.

Key words: Abiotic stress, atmospheric pollution, climatic change, environmental pollution, forest decay, forest ecosystems, forest species, ozone, reactive oxygen species, tropospheric ozone.