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MORPHOMETRIC ANALYSIS OF EPIDERMAL DIFFERENTIATION IN PRIMARY ROOTS OF ZEA MAYS
Author(s) -
Moore Randy,
Smith Houston S.
Publication year - 1990
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.1537-2197.1990.tb14462.x
Subject(s) - cuboidal cell , epidermis (zoology) , biology , meristem , root cap , elongation , vacuole , columnar cell , anatomy , botany , cytoplasm , microbiology and biotechnology , genetics , materials science , shoot , ultimate tensile strength , metallurgy , epithelium
Epidermal differentiation in primary roots of Zea mays was divided into six cell types based on cellular shape and cytoplasmic appearance. These six cell types are: 1) apical protoderm, located at the tip of the root pole and characterized by periclinally flattened cells; 2) cuboidal protoderm, located approximately 230 μ m from the root pole and characterized by cuboidal cells; 3) tabular epidermis, located approximately 450 μ m from the root pole and characterized by anticlinally flattened cells; 4) cuboidal epidermis, located approximately 900 μ m from the root pole and characterized by cuboidal cells having numerous small vacuoles; 5) vacuolate cuboidal epidermis, located approximately 1,500 μ m from the root pole and characterized by cuboidal cells containing several large vacuoles; and 6) columnar epidermis, located approximately 2,200 μ m from the root pole (i.e., at the beginning of the zone of elongation) and characterized by elongated cells. We also used stereology to quantify the cellular changes associated with epidermal differentiation. The quiescent center and the apical protoderm have significantly different ultrastructures. The relative volume of dictyosomes increases dramatically during the early stages of epidermal differentiation. This increase correlates inversely with the amount of coverage provided by the root cap and mucilage.