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ULTRASTRUCTURAL STUDIES OF ABSCISSION IN PHASEOLUS: LOCALIZATION OF PEROXIDASE
Author(s) -
Webster Barbara D.,
Dunlap Tania W.,
Craig Mary E.
Publication year - 1976
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.1002/j.1537-2197.1976.tb11865.x
Subject(s) - abscission , phaseolus , biology , ultrastructure , osmium tetroxide , endoplasmic reticulum , vacuole , glutaraldehyde , ethephon , peroxidase , incubation , cytoplasm , cytochemistry , cell wall , botany , biophysics , electron microscope , biochemistry , ethylene , chemistry , chromatography , enzyme , physics , optics , catalysis
Segments of leaf abscission zone tissue of Phaseolus vulgaris L. cv. Red Kidney were fixed in glutaraldehyde, incubated to demonstrate peroxidase activity in medium containing 3,3'‐diaminobenzidine (DAB) and postfixed in osmium tetroxide. Electron microscopic observation of treated tissue revealed pronounced deposition of highly electron‐opaque material in the form of granules or globules in cell walls, on mitochondrial membranes, associated with rough endoplasmic reticulum and along the plasmalemma and tonoplast. This distribution pattern was typical of both non‐treated and ethephon‐treated tissue. Ethephon‐treated material also contained these granules within cytoplasmic vacuoles. It is suggested that p H of the incubation medium may affect localization sites and that exposure of tissue to light during incubation may modify localization patterns. Differing patterns of distribution of the reaction product in treated and non‐treated tissue may reflect changes in membrane permeability and microfibrillar modifications related to ethephon treatment.