VIEW ARTICLE

Effect of Puccinia graminis f. sp. tritici on Ozone Injury in Wheat. Allen S. Heagle, Plant Pathologist, Southern Region, Agricultural Research Service, U.S. Department of Agriculture, North Carolina State University, Raleigh 27607; Linda W. Key, Microbiologist, Environmental Protection Agency, National Environmental Research Center, Research Triangle Park, North Carolina 27711. Phytopathology 63:609-613. Accepted for publication 27 November 1972. DOI: 10.1094/Phyto-63-609.

Significantly less ozone injury occurred in mesophyll cells in the substomatal areas of wheat leaves inoculated with urediospores of Puccinia graminis f. sp. tritici than in noninoculated leaves. The protective effect was present in inoculated areas when plants were exposed to ozone 2, 3, or 4 hr after the start of urediospore incubation. The mesophyll cells under stomata with appressoria attached were rarely injured. Mesophyll cells under stomata without appressoria attached were also protected in areas of the leaf that were inoculated. Noninoculated areas were not protected. These results suggest that a diffusible substance is produced by germinating spores and infection structures that results in protection of localized areas of wheat leaf tissue from ozone injury.