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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.
- Fall '09