This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via Web of Science (45) Citing Articles via Google Scholar Google Scholar Articles by Olszyk, D. M. Articles by Tibbitts, T. W. Search for Related Content PubMed PubMed Citation Articles by Olszyk, D. M. Articles by Tibbitts, T. W. Agricola Articles by Olszyk, D. M. Articles by Tibbitts, T. W.

Articles

Stomatal Response and Leaf Injury of Pisum sativum L. with SO₂ and O₃ Exposures ^1,2

I. INFLUENCE OF POLLUTANT LEVEL AND LEAF MATURITY

Department of Horticulture, University of Wisconsin, Madison, Wisconsin 53706

Plants of Pisum sativum L. `Alsweet' were grown under a controlled environment and exposed to SO₂ and O₃ to determine whether changes in stomatal aperture during exposure were related to subsequent leaf injury. Stomata consistently closed with injurious levels of SO₂ and O₃. Measurements with diffusion porometers demonstrated 75 and 25% lower conductance with SO₂ and O₃ exposures, respectively, compared to the conductance of control plants. Stomata also showed a closing response with noninjurious levels of SO₂ but an opening response with noninjurious levels of O₃. Stomata closed to the same degree with combinations of SO₂ plus O₃ as with SO₂ alone. Stomata of expanding leaves closed more during pollutant exposures than stomata of expanded leaves. The abaxial and adaxial stomata both exhibited closure with SO₂ and combinations of SO₂ plus O₃, but abaxial stomata tended to close and adaxial stomata tended to open with exposure to O₃ alone.

The changes in stomatal aperture were not closely correlated with the amount of leaf injury produced by different pollutant levels. Stomata closed, not only with exposure to pollutant levels that caused severe necrosis, but also with levels that caused only a trace of injury. There was no evidence of a reduced amount of closure or even stomatal opening with combinations of SO₂ and O₃ compared to plants exposed to the pollutants alone to explain the large amount of injury to plants exposed to pollutant combinations.

¹ Contribution from Horticulture Department and Institute for Environmental Studies, University of Wisconsin, Madison, WI 53706. This project has been financed in part by Federal funds from the Environmental Protection Agency under Grant R803971 and by the Wisconsin Public Service Corporation, the Madison Gas and Electric Company, the Wisconsin Power and Light Company, and the College of Agricultural and Life Sciences, University of Wisconsin.

² The contents do not necessarily reflect the view or policies of the Environmental Protection Agency, Department of Horticulture, University of Wisconsin, or the supporting corporations, nor does mention of a trade name for a commercial product constitute endorsement or recommendation for use.