Axial wood parenchyma cells are not in contact with axial phloem parenchyma once a layer of tracheids
has formed to separate them from the cambium, whereas wood rays are intercontinuous with phloem rays via living cells of the cambium.
Abbreviations used in the figures of this study: A = aperture; AP = appressorium; B = pit border; F = fiber; H = hyphae; L = lipid bodies; M = margo of pit membrane; P = parenchyma cell; PA = perforation in end wall of vessel element; T = torus; VT = vascular tracheid
. All wood anatomy images are of Osmanthus armatus, except for Figure 6, which is from O.
The long tapering tracheids
constitute the dominant cell type of the conifer axial system and ensure both water conduction and tree support.
also function in water transport but are less efficient in doing so because they are smaller in diameter, and the end walls are not totally dissolved as the cell reaches maturity.
Xylem conducting elements include tracheids
Lignin appeared to be completely removed from the cell corner middle lamella regions, but tracheids
were still joined in other parts of the middle lamella.
Although three samples exhibited helical checking on the tracheids
, none exhibited spiral thickenings.
Norway spruce wood consists to 90% of small water-conducting elements with a diameter of about 10-40 [micro]m and a length of 1-4 mm (tracheids
Everyone has seen these tubes, which biologists call "vessels" and "tracheids
." They help form the grain in wood.
Green, "The Effect of Pulping Upon the Dimensions of Wood Tracheids
," Wood Fiber 7 (3), 226-233 (1975).
The crown core is composed of an intertwining series of vascular bundles, fibers, and tracheids
interspersed with parenchyma cells in a generally inverted cone shape.