VIEW ARTICLE

Electrolyte Leakage and Membrane Damage in Relation to Bacterial Population, pH, and Ammonia Production in Tobacco Leaf Tissue Inoculated with Pseudomonas pisi. R. N. Goodman, Professor, Department of Plant Pathology, University of Missouri, Columbia 65201; Phytopathology 62:1327-1331. Accepted for publication 25 May 1972. DOI: 10.1094/Phyto-62-1327.

When 10⁸ cells/ml Pseudomonas pisi were injected into tobacco foliage which was subsequently kept in either a normal room or humid chamber atmosphere, typical visual symptoms of the hypersensitive reaction (HR) (flaccidity and necrosis) developed only in the former environment. The bacterial population decreased 12 hr after inoculation in tissue held in room atmosphere, and increased in the humid chamber during the 48 hr of the experiment. Membrane damage and electrolyte leakage, consequences of HR, occurred in both environments approximately 6 hr after inoculation. This is 18 hr before the pH reaches 8.0, and 42 hr before NH₃ is evolved; hence, neither is causally related to either membrane damage or electrolyte leakage. The evolution of NH₃ only at 48 hr is a reflection of continued metabolic activity of the bacteria in the humid chamber environment.