VIEW ARTICLE

Disease Detection and Losses

Effects of Sulfur Dioxide and Nitrogen Dioxide on Vegetative Growth of Soybeans. C. I. Klarer, Graduate assistant, Agricultural Research Service, U.S. Department of Agriculture, North Carolina State University, Raleigh 27650; R. A. Reinert(2), and J. S. Huang(3). (2)Plant pathologist and professor, Agricultural Research Service, U.S. Department of Agriculture, North Carolina State University, Raleigh 27650; (3)Plant pathologist and associate professor, Department of Plant Pathology, North Carolina State University, Raleigh 27650. Phytopathology 74:1104-1106. Accepted for publication 1 May 1984. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1984. DOI: 10.1094/Phyto-74-1104.

Greenhouse grown soybeans, Glycine max ' Bragg,' inoculated with Rhizobium japonicum were exposed to sulfur dioxide (SO₂) (0.0, 0.2, 0.3 ppm) and nitrogen dioxide (NO₂) (0.0, 0.1, 0.2 ppm) singly and in combination. Three-hour exposures were initiated at 3 wk postemergence and continued every other day. Plants were harvested after 15 exposures. Number and fresh weight of nodules and fresh and dry weight of stems, leaves, and roots were recorded. A red pigmentation and stippling developed on leaves after the initial exposure to 0.3 ppm SO₂ and all SO₂ + NO₂ mixtures. A chlorotic mottle developed in plants after several exposures to SO₂ + NO₂ mixtures. The interaction of SO₂ and NO₂ caused a significant weight reduction in all plant parts measured except the stems. Linear reductions in weight were related to pollutant-dose. Variables measured generally showed linear reductions in weight due to the interaction of the pollutants.