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Membrane Permeability in Plants: Changes Induced by Host-Specific Pathotoxins. Robert W. Keck, Research Associate, Department of Botany, University of Illinois, Urbana, Illinois 61801; T. K. Hodges, Associate Professor, Department of Botany and Plant Pathology, Purdue University, Lafayette, Indiana 47907. Phytopathology 63:226-230. Accepted for publication 19 July 1972. DOI: 10.1094/Phyto-63-226.

The effect of host-specific pathotoxins on the permeability of the plasma membrane and the tonoplast of host cells was determined using an ion efflux, compartmental analysis procedure. Toxin produced by Helminthosporium victoriae dramatically increased the permeability of both the plasma membrane and tonoplast of root cells in a susceptible cultivar (Park) of Avena sativa, but not in a resistant cultivar (Goodfield). A culture extract containing H. maydis race T toxin increased the permeability of plasma membranes of Zea mays leaf cells, but this effect was not host-specific. Under the experimental conditions used in this study, the H. maydis race T toxin, contained in the culture extract, had no effect on tonoplast permeability of host cells.