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Physiology and Biochemistry

Time-Course and Antioxidant Inhibition of Ethylene Production by Victorin-Treated Oat leaves. Harry Wheeler, Department of Plant Pathology, University of Kentucky, Lexington, KY 40506; Ellen Elbel, Department of Plant Pathology, University of Kentucky, Lexington, KY 40506. Phytopathology 69:32-34. Accepted for publication 2 August 1978. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-32.

Although an increase in ethylene production is one of the most sensitive responses to victorin, no increase in this gas was detected during the first 30 min after susceptible oat leaves were treated with this pathotoxin. These results do not support the concept that ethylene triggers initial changes in permeability and electrochemical potentials that occur within 5 min after exposure to victorin. The results also emphasize the significance of a similar 30-min lag in less sensitive responses to victorin such as increases in respiration, decreases in C₆/C₁ ratios, and other changes clearly linked to metabolism. Antioxidants, of which α-tocopherol was the most effective, inhibited ethylene production by victorin-treated tissues and also suppressed pathologic effects of victorin on losses of electrolytes and chlorophyll. Failure of antioxidants to suppress ethylene production in healthy control leaves lends support to evidence that the pathways leading to ethylene evolution in diseased tissues differ from those in healthy plants.