Absorption of air pollution by plants, and consequences for growth.

There is now great concern that air pollutants (especially sulfur dioxide, ozone, and oxides of nitrogen) can alter the physiological processes of plants, thereby affecting patterns of growth. Air pollutants cause damage to leaf cuticles and affect stomatal conductance. They can also have direct effects on photosynthetic systems, leaf longevity, and patterns of carbon allocation within plants. Pollutants interact with other environmental factors, and may alter plant-environment relationships on a regional scale. In this article, Winner and Atkinson summarize current knowledge of the effects of air pollutants on plant growth and physiology, and indicate the new directions of research now under way in North America and Europe.