Submitted to: Plant Disease
Publication Type: Proceedings
Publication Acceptance Date: 1/1/2000
Publication Date: 1/1/2001
Citation: Krupa, S.V., Mcgrath, M.T., Andersen, C.P., Booker, F.L., Burkey, K.O., Chappelka, A., Chevone, B., Pell, E., Zilinskas, B. 2001. Ambient ozone and plant health. Plant Disease 85:4-17. Interpretive Summary: Ozone is an air pollutant that is toxic to plants, causing visible injury to foliage and a reduction in the growth and yield of many agronomic, horticultural and forest species. Ground level ozone is formed by the action of sunlight on volatile hydrocarbons and nitrogen oxides produced during fossil fuel combustion. Although frequently considered an urban problem, ozone is actually a regional problem because weather systems transport the pollutant into agricultural areas and forests. Ozone enters the plant via leaf stomata and initiates a series of metabolic changes that result in characteristic visible injury that is described and documented with color photographs. In addition to growth and yield reductions, ozone has the potential to indirectly affect plants through altered patterns of insect feeding and pathogen infection and changes in break down of plant residues in the soil. Ozone-sensitive and tolerant plants have been identified and are being used as bio-indicator systems to monitor ozone problems. Effects on the bio-diversity of natural ecosystems are possible over time if tolerant plants gradually dominate plant communities.
Technical Abstract: Ozone is an air pollutant that is toxic to plants, causing visible injury to foliage and a reduction in the growth and yield of many agronomic, horticultural and forest species. A major source of ground level ozone is the photochemical reaction of sunlight with volatile hydrocarbons and nitrogen oxides. These ozone precursors are primarily generated in urban areas as products of fossil fuel combustion. Ground level ozone becomes a regional problem because weather systems transport ozone precursors and ozone to agricultural areas and forests. In this review, ozone-induced visible leaf injury is described and supported with pictorial examples for several crop and tree species. Current knowledge is summarized for ozone effects on plants in relation to: (1) physiological responses including effects on stomatal conductance, photosynthesis, antioxidant metabolism, and defense responses common to ozone injury and pathogen attack, (2) ozone-sensitive and tolerant plants and their use as bio-indicators, (3) growth and yield responses, (4) plant-insect and plant-pathogen interactions, (5) soil decomposition of plant residues including impacts on nutrient cycling, and (5) effects on plant community structure and bio- diversity. Agricultural experiment station support of ozone research is highlighted in terms of the past accomplishments and future directions of the Northeast Regional Project NE-176.