The role of the abscission zone in development of the tobacco inflorescence.
Item
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Title
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The role of the abscission zone in development of the tobacco inflorescence.
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Identifier
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AAI9830785
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identifier
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9830785
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Creator
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Zhang, Yi.
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Contributor
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Adviser: Jack G. Valdovinos
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Date
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1998
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Language
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English
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Publisher
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City University of New York.
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Subject
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Biology, Plant Physiology | Biology, Botany
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Abstract
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The abscission zone of the tobacco flower pedicel is a regulatory tissue in the development of the tobacco inflorescence. The abscission zone of each flower pedicel acts as a node (flower node). It is composed of several layers of small cells containing dense cytoplasm in the cortex and the pith on both sides of the groove mark. The proximal side is a potential meristem for flower bud formation and the distal side is the separation layer responsible for the induction of flower abscission. The terminal tobacco inflorescence is a typical compound cymose with many branch types which include monochasium branch types to trichasium branch types at each flower node. Except for the terminal flower most other flowers are initiated from the prior flower's abscission zone. The young inflorescence increases flower number rapidly by developing dichasium and trichasium branch types. The abscission zone is morphologically differentiated when the flower bud is about 1.2 mm in length. Flower bud formation may occur at the base of a flower pedicel even before the abscission zone becomes morphologically differentiated. The flower bud become inducible to abscission when the flower bud reaches about 10 mm in length. The abscission of a flower is prevented by rapid secondary growth of the vascular tissue after anthesis. Some flowers can be broken not at the abscission zone but further out the pedicel before any induction with ethylene. The abscission zone may not be the weakest point because of morphological differentiation but it becomes the weakest point in all inducible flowers after three hours treatment of ethylene. The abscission zone in a thin-layer explant is the most active tissue with respect to flower bud formation and other organogenesis under tissue culture conditions. Flower bud formation and other organogenesis can be induced from the proximal side of the abscission zone rapidly with proper conditions. The combination indole-3-acetic acid and kinetin causes the flower bud formation to develop from two ends of the abscission zone in an explant. However the combination of {dollar}\alpha{dollar}-naphthalene-acetic acid and 6-benzylamino-purine causes the flower bud formation to develop from the whole abscission zone in an explant.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
