Tracheid and vessel elements

Tracheid and vessel elements Trn Th HinHong Ngc nh

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Dead cells .They are nonliving at maturity.Tubular cell.Both are more or less elongated cells that have lignified secondary walls.Form long columns, place one above the other .

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Figure 1

Xylem

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www.trungtamtinhoc.edu.vnDifferenceTracheidLong, tubular cells with tapering ends.Tracheids are imperforate cells having only pit-pairs on their common walls.Water flowing from tracheids to tracheid must pass through the pit membranes of pit-pair in their overlapping wallVessel elementsCells are shorter . Cells arent as tapering as tracheids.Vessel elements are perforated at their end.Perforations are areas lacking both primary and secondary walls through which the vessel elements are interconnected.

www.trungtamtinhoc.edu.vnTypes of tracheid

www.trungtamtinhoc.edu.vnPerforations plateA single perforation (simple perforation plate).Several perforations (multiple perforation plate)Scalariform perforation plate.Reticulate perforation plate.Foraminate perforation plate.

www.trungtamtinhoc.edu.vnPitsSimple and bordered pits are found in the secondary walls of tracheid and vessel elements of the latest formed primary xylem and of the secondary xylem

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