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Light and Electron Microscopy of Plant Leaf Cells After Short-Term Exposure to Bromine Gas. S. J. Strauss, Department of Plant Pathology, University of Arkansas, Fayetteville 72701; K. S. Kim(2), and L. E. Murry(3). (2)Department of Plant Pathology, University of Arkansas, Fayetteville 72701; (3)Botany and Bacteriology, University of Arkansas, Fayetteville 72701. Phytopathology 72:793-800. Accepted for publication 26 October 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-793.

Immediate and delayed (24 hr) effects of a 20-min exposure of cowpea primary leaf tissue to 1, 3, or 5 ppm bromine gas were studied with light and electron microscopy. The formation of circular, adaxial, and abaxial surface lesions and leaf compression were the most visible changes. Major cytological modifications included cytoplasmic vacuolation, disruption of cellular membranes, plasmolysis, alteration of nucleolar structure, anticlinal cell wall interdigitation, and collapse of the protoplast and/or cell wall. Although degree and type of injury varied, all epidermal and mesophyll cells were affected by the treatments. Spongy mesophyll cells surrounded by large air spaces were more severely affected by the bromine gas than were the closely packed palisade mesophyll cells. At 1 ppm bromine, certain cellular changes such as adaxial depression and anticlinal cell wall interdigitation were reversed when the exposed plants were returned to a normal environment; at 5 ppm bromine, however, the entire cell population immediately became irreversibly necrotic.

Additional keywords: air pollutant, cytological effects.