tracheid


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Fig. 299 Tracheid . General structure.

tracheid

any of several structures found in XYLEM, consisting of a cell which is long, slender and tapered with heavily lignified walls surrounding an empty lumen, the protoplasm having died.

The wall thickening can be continuous with BORDERED PITS, or else arranged in a variety of patterns, annular, helical and ladder-like. See Fig. 299 . Tracheids form the water-conducting tissues of GYMNOSPERMS, but are found also amongst the xylem vessels of ANGIOSPERMS

References in periodicals archive ?
In vesselless woody groups, tracheid length could be employed as a way of approximating the length of fusiform cambial initials.
Adjoining tracheids are still joined in the middle lamella region between cell corners, pointing possibly to a greater resistance of lignin in this region to peracetic acid treatment than lignin in the cell corner middle lamella.
This tensile strain is a consequence of adhesive forces between the water molecules and the inner conduit walls when "free" water in the tracheids comes under tension [5].
1b), longitudinal tracheids are the most common type of cell, and intercellular transport is facilitated by ray cells and pits.
Water moves through the xylem via vessel elements and tracheids in angiosperms and tracheids in the gymnosperms.
Vascular cambium developed in one year-old seedlings; secondary" xylem was distinguished from the mature shoot by the occurrence of wide band tracheids and lack of fibers.
Ellipse detection and phase demodulation for wood grain orientation measurement based on the tracheid effect.
The inherent taxonomic interest of so many distinctive features in which Stixis resembles Forchhammeria seems clear: successive cambia, ray histology, tracheid presence, vestured pits, and crystal-bearing cells in conjunctive tissue.
The liquid water in the tracheids is under tension, caused by transpiration from the needles.
According to a previous study, nano-Ag/Ti[O.sub.2] particles attach mostly to the axial tracheid and fiber of wood, while a small fraction penetrates into wood cell lumens and attach to cell walls through chemical bonding or physical interactions (Wang 2012).
Tracheid diameter is the key trait determining the extent of freezing-induced embolism in conifers.