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Physiology and Biochemistry

Effect of an Ozone Injury Retardant Chemical on Isozyme Profiles from Alfalfa Callus in Vitro. John P. Rier, Jr., Department of Botany, Howard University, Washington, DC 20059; Virendar K. Sood(2), Aaron Whitaker(3), and Colin Watson(4). (2)(3)(4)Department of Botany, Howard University, Washington, DC 20059. Phytopathology 73:1262-1266. Accepted for publication 4 April 1983. Copyright 1983 The American Phytopathological Society. DOI: 10.1094/Phyto-73-1262.

Plant ozone injury retardant N-[2-(2-oxo-1-imidazolidinyl)-ethyl]-N’-phenylurea (EDU or ethylenediurea) at 1.0 ppm inhibited growth of callus of alfalfa cultivars Williamsburg (ozone-sensitive) and MSB-CW5An2 (ozone-insensitive) germplasm of Medicago sativa. The presence of EDU (0.1 ppm) in the growth medium increased the number of protein and peroxidase isozyme bands in alfalfa cultivar Williamsburg stem callus and ozone modified their intensities. Protein profiles of MSB stem callus from media containing EDU or exposed to ozone were unchanged. Marked differences were observed between the peroxidase profiles of ozonated and control ozone-insensitive stem callus from media containing EDU. Protein profiles of ozonated ozone-insensitive leaf callus differed slightly from controls. The peroxidase profile of ozonated ozone-sensitive leaf callus was not altered when its growth medium contained EDU, but when it was absent, changes were observed in these profiles.