Libriform cells

Hardwoods contain several cell types, specialized for different functions (Fig. 1-9). The supporting tissue consists mainly of libriform cells, the conducting tissue of vessels with large cavities, and the storage tissue of ray parenchyma cells. In addition, hardwood contains hybrids of the above-mentioned cells which are classified as fiber tracheids. Although the term fiber is frequently used for any kind of wood cells, it more specifically denotes the supporting tissue, including both libriform cells and fiber tracheids. In birch these cells constitute 65 to 70% of the stem volume. 

Libriform cells are elongated, thick-walled cells with small cavities containing some simple pits. The dimensions of birch libriform fibers are 0.8-1.6 mm or on an average 1.1 -1.2 mm (length), 14 40 /xm (width), and 3-4 /xm... 

A. Fibers 1. Libriform fibers 2. Fiber tracheids 3. Vasicentric tracheids B. Axial parenchyma C. Vessel elements Ray parenchyma 1. Procumbent cells 2. Upright cells Homocellular rays 1 or 2 Heterocellular rays 1 and 2... 

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See also in sourсe #XX -- [ ]

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