Spruce tracheids

Fig. 1-6. Cells of coniferous woods. An earlywood (a) and a latewood (b) pine tracheid, an earlywood spruce tracheid (c), ray tracheid of spruce (d) and of pine (e), ray parenchyma cell of spruce (f) and pine (g) (llvessalo-Pfaffli, 1967).

Fig. 4-11. Transverse section of a spruce tracheid photographed in UV light (240 nm) (Fergus et a/., 1969). The densitometer tracing has been taken across the tracheid wall along the dotted line. S, secondary wall ML, compound middle lamella CC cell corner.

Fig. 1.3. Ultraviolet micrograph of transverse section of black spruce tracheid with the microdensitometer trace taken across dotted line...

Westermark U, Lidbrandt O, Eriksson I (1988) Lignin distribution in spruce (Picea abies) determined by mercurization with SEM-EDXA technique. Wood Sci Technol 22 243-250 Whiting P, Goring DAI (1982) Chemical characterization of tissue fractions from the middle lamella and secondary wall of black spruce tracheids. Wood Sci Technol 16 261-267 Wood JR, Goring DAI (1971) The distribution of lignin in stem wood and branch wood of Douglas-fir. Pulp Pap Mag Can 72 T95-T102... 

Figure 33. Spruce tracheids with cell wall degradation proceeding from the lumen (arrows), and tracheids with totally degraded secondary cell walls.

COMPOSITION OF SPRUCE TRACHEID CELL WALLS (Weight % of Individual Cell Walls)... 

The percentages of total biopolymer that reside within the different cell wall layers are illustrated in Figure 3. These percentages depend both on the compositions described and on the relative volumes of the layers themselves. The relative volumes vary between earlywood and latewood, and will be discussed for earlywood. On the basis of microscopic observation (4), the CML region accounts for about 12% of the total tissue volume of spmce earlywood. This wall component contains approximately 4, 21, and 27%, respectively, of the total cellulose, hemicellulose, and lignin in spruce tracheids. The adjacent Si layer has a comparable volume and contains 9, 23, and 10% of the total cellulose, hemicellulose, and lignin, respectively. 

DISTRIBUTIONS OF POLYMERS IN SPRUCE TRACHEIDS (Percentages of Total Polymer in Early wood)... 

Figure 3. The percentages of the total cellulose, hemicellulose, and lignin that occur within the different cell wall layers of spruce tracheids, (Constructed from data in ref. 4.)...

Figure I. Bore holes in spruce tracheid made by the hyphae of white rot fungus Polyporus versicolor (X 20,250). Reproduced, with permission, from Ref. 43. Copyright 1965, Syracuse University Press.

Figure 3.4 Distribution of lignin in earlywood tracheids of black spruce.

Immunofluorescence techniques have been used to establish the sites of localization of / -glucosidases in spruce hypocotyls (9,61) and chickpea (Cicer arietinum L.) seedlings (46,62,63). In these investigations, the (3-glucosidases were associated with lignified elements (tracheids and endo-dermis tissue), as well as those containing suberin and cutin. 

Figure 5. Holocellulose of spruce-wood tracheid. Control sample...

Fig. 1-2. Transverse section of xylem and phloem of red spruce (P/cea rubens). CZ, cambial zone DP, differentiating phloem MP, mature phloem with sieve cells (sc) and tannin cells (tc) DX, differentiating xylem with ray cells and tracheids (tr) MX, mature xylem, earlywood (EW) with resin canals (rc), lined with epithelial cells (ec) LW, latewood. Note that each ray continuous from the xylem, through the cambial zone, and into the phloem. Light micrograph by L. W. Rees. Courtesy of Dr. T. E. Timell.

Fig. 1-7. Radial section of a spruce ray (above) and radial and tangential section of a pine ray (below), (a) Longitudial tracheids. (b) Rows of ray tracheids (small bordered pits), (c) Rows of ray parenchyma, (d) Pits in the cross fields leading from ray parenchyma to longitudial tracheids. (e) A bordered pit pair between two tracheids. (f) A bordered pit pair between a longitudial and a ray tracheid (llvessalo-Pfaffli, 1967).

The average length of Scandinavian softwood tracheids (Norway spruce and Scots pine) is 2-4 mm and the width in the tangential direction is 0.02 -0.04 mm (Fig 1 -8). The thickness of earlywood and latewood tracheids is 2-4 /u,m and 4-8 /xm, respectively. 

The width of a ray usually corresponds to one cell. Several parenchyma cell files are placed on top of one another. Ray tracheids are often located at the upper and lower edges of this tier (Fig. 1-7). Parenchyma cells are thin-wailed, living cells. In Norway spruce and Scots pine their length and width vary between 0.01-0.16 mm and 2-50 tm, respectively. The ray tracheids are of the same size and also provide liquid transport in the radial direction. Rays in Scots pine, for example, contain 25-31 ray tracheids per square millimeter in a tangential section. 

TABLE 4-4. Distribution of Lignin in Spruce (Black Spruce, Picea mariana) Tracheid"... 

TABLE 5-1. Data on Resin, Parenchyma Cells, and Ray Tracheids of Scots Pine (Pinus sylvestris) and Norway Spruce (Picea abies)a... 

To determine the distribution of lignin from bromine analysis, it is essential to know the reactivity of bromine toward lignin in different morphological regions. For black spruce (Picea mariana), Douglas-fir (Pseudotsuga menziesii) and loblolly pine (Pinus taeda), the lignin in the secondary wall of tracheids is 1.7... 

JS Bond. Raman Microspectroscopic Investigation of Patterns of Molecular Order in the Secondary Walls of Black Spruce and Loblolly Pine Tracheids. Ph.D. thesis, Georgia Institute of Technology, 1991. 

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