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Leakage of Electrolytes and Phenols from Apple Leaves Caused by Virulent and Avirulent Strains of Erwinia amylovora. S. K. Addy, Formerly Graduate Student, Department of Plant Pathology, University of Missouri, Columbia 65201, Currently Professor, Department of Plant Pathology, Assam Agricultural University, Jorhat 785013, Assam, India; Phytopathology 66:1403-1405. Accepted for publication 2 June 1976. Copyright © 1976 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-66-1403.

Apple leaves infiltrated with virulent and avirulent strains of Erwinia amylovora showed a linear relationship of leakage of electrolytes and total phenols during the first 5 hours. Thereafter, the rate of increase of electrolyte and phenol concentrations was nonlinear. With the avirulent strain leakage of phenol was 1 hour earlier than the leakage of electrolytes. With the virulent strain leakage of phenols and electrolytes occurred simultaneously. Both phenomena occurred sooner in tissues infiltrated with the avirulent strain. Both occurred well in advance of visible browning symptoms which were evident about 12 hours after infiltration.

Additional keywords: hypersensitive reaction, Erwinia amylovora, electrolyte leakage, phenols, and resistance.