Developmental and Structural Section
Westby, A.P. .
Nonessentiallity of Cellular Divisions for the Differentiation of Procambium.
During germination and seedling growth, the coleoptiles and cotyledons of plantlets exhibit polarized growth and additional differentiation of procambium. Through my studies I found that the relationship between the primary leaf’s length and width is the same in normally developing plantlets as in plantlets developing with minimal cell division induced by treatment of 1000cGy- irradiation to the unsown grain. Irradiated and non-irradiated, Triticum, Avena, and Helianthus, seedlings sharing the same intra-species allometric constant for the growth of the primary leaf, were found to exhibit quite different cell sizes, shapes, and numbers both overall and in their vascular bundles. It is generally thought that most of the new cell plates formed within the procambium arise periclinal to the axis of elongation. Although, cellular divisions are necessary for continued growth and development, this study demonstrates that concurrent cell divisions are not required for differentiation of procambium tissue. Specifically, plantlets that developed in the absence of cellular division exhibited comparable differentiation of procambium tissue to the plantlets allowed to develop with cellular divisions. The majority of the new cell plates formed before the observation period are assumed to have occurred periclinal to the greatest axis of elongation during the growth period studied. Based on these observations I conclude that: (1) cellular divisions do not dictate the overall shape and size of the plant organism, (2) cellular divisions instead must accommodate the overall growth of the plant, and (3) cellular divisions are not essential for the differentiation of procambium tissue.
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1 - Emporia State University, Biology Department, 1200 Commercial St. Emporia State University: Biology Dept. Box 4050, Emporia, Ks, 66801, United States
Presentation Type: Poster:Posters for Sections
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM