Tissues213-page9 - • End walls of vessels are perforated...

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Plant Tissues - 9 Vascular Tissues A complex tissue system produced from procambium in primary growth and from vascular cambium in secondary growth Functions Conduction of water, solutes and some minerals throughout the plant Support for the plant Some food storage Two types Xylem Phloem Xylem Moves H 2 O and some minerals up through plant from roots to leaves May move dilute solutes after seasonal dormancy Xylem tissue is also used for food storage, especially in roots The plant part that we refer to as wood is xylem tissue Composed of “tracheary elements” Vessels (Vessel elements)(Only in Angiosperms and Gnetophytes) Elongated cells with secondary walls that connect to form tubes Die at maturity (genetic apoptosis)
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Unformatted text preview: • End walls of vessels are perforated (literally no cell wall regions) Water moves more freely from cell to cell through the perforations • Generally fairly large diameter • Characterized by a variety of wall thickenings (rings, spirals, pitted, etc). Primary xylem that elongates more will have rings or spiral thickenings. Metaxylem and secondary xylem stretches less and is more rigid. Vessels: Longitudinal section Cross section Differentiation of vessel elements involves lateral expansion, helical secondary wall formation, lysing of the cell's cytoplasm and destruction of the primary cross walls at the perforation site....
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This note was uploaded on 01/08/2012 for the course BIO 213 taught by Professor Makina during the Fall '09 term at SUNY Stony Brook.

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