On the Lamellar Structure of the Tracheid Cell Wall

Abstract

It is clear that cross sections of wood cells show a lamellar structure. This paper investigates the orientation of this lamellar structure of spruce (Picea abies) tracheids using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Cross sections of spruce wood were produced through fracturing in longitudinal bending and tensile testing. When investigated with SEM, the fracture surfaces show a structure of mostly larger radial lamellae, in the order of 30 - 100 nm, i.e., agglomerations of a few cellulose aggregates. Thin transverse sections of the fracture zones investigated with atomic force microscopy show concentric lamellae with a width in the order of a single cellulose aggregate, i.e., 15 - 25 nm. No structural connection to the splinters in the radial direction can be seen. It is suggested that the radial lamellar structure is a consequence of the energy released during fracturing of the wood samples and that the undistorted wood has a concentric lamellar structure on a smaller structural level.

Key words

Atomic force microscopy - ultrastructure - Picea abies - Norway spruce - lamellar structure - scanning electron microscopy - fracture

References

• 01 Argon,  A. S.. (1974) Statistical Aspects of Fracture. Composite materials (5) 8. Broutman, L. J., ed. New York and London; Academic Press pp. 154-189
• 02 Awerbuch,  J., and Hahn,  H. T.. (1979) Off-Axis Fatigue of Graphite/Epoxy Composite. Fatigue of fibrous composite materials. Wheeler, J. B. et al., eds. Philadelphia; American society for testing and materials pp. 243-273
• 03 Bailey,  I. W.. (1938);  Cell wall structure of higher plants.  Industrial and Engineering Chemistry. 30 40-47
• 04 Blanchette,  R. A.,, Obst,  J. R.,, and Timell,  T. E.. (1994);  Biodegradation of compression wood by white and brown rot fungi.  Holzforschung. 48 34-42
• 05 Cooper,  G. A.. (1974) Micromechanics Aspects of Fracture and Toughness. Composite materials (5) 8. Broutman, L. J., ed. New York and London; Academic Press pp. 415-448
• 06 Fahlén,  J., and Salmén,  L.. (2001);  Cross-sectional structure of the secondary wall of wood fibers as affected by processing.  Journal of Material Science. in print
• 07 Fengel,  D.. (1970);  Ultrastructural Behaviour of Cell Wall Polysaccharides.  Tappi. 53 497-503
• 08 Gu,  H.,, Zink-Sharp,  A.,, and Sell,  J.. (2000) Anisotropic Shrinkage - Influence of Microfibril Angle. Proceedings of International Conference on Wood and Wood Fiber Composites. Aicher, S., ed. Stuttgart; Univ. Stuttgart pp. 15-22
• 09 Heyn,  A.. (1977);  The ultrastructure of wood pulp with special reference to the elementary fibril of cellulose.  Tappi. 60 159-161
• 10 Kerr,  A. J., and Goring,  D. A.. (1975);  The ultrastructural arrangement of the wood cell wall.  Cellulose Chemistry and Technology. 9 536-573
• 11 Larsen,  M. J.,, Winandy,  J. E.,, and Green,  F.. (1995);  A proposed model of the tracheid cell wall of southern yellow pine having an inherent radial structure in the S₂ layer.  Materials and Organisms. 29 197-210
• 12 Page,  D. H.. (1976);  A note on the cell-wall structure of softwood tracheids.  Wood and Fiber. 7 246-248
• 13 Parameswaran,  N., and Liese,  W.. (1976);  On the fine structure of bamboo fibers.  Wood Science and Technology. 10 231-246
• 14 Parameswaran,  N., and Liese,  W.. (1980);  Ultrastructural aspects of bamboo cells.  Cellulose Chemistry and Technology. 14 587-609
• 15 Piggott,  M. R.. (1980) Load bearing fibre composites. Exeter; A Wheaton Co. pp. 277
• 16 Ruel,  K.,, Barnoud,  F.,, and Goring,  D. A. I.. (1978);  Lamellation in the S₂ layer of softwood tracheids as demonstrated by scanning transmission electron microscopy.  Wood Science and Technology. 12 287-291
• 17 Salmén,  L., and Olsson,  A.-M.. (1998);  Interaction between hemicelluloses, lignin and cellulose: Structure - property relationships.  Journal of Pulp and Paper Science. 24 99-103
• 18 Scallan,  A. M.. (1974);  The structure of the cell wall of wood - a consequence of anisotropic inter-microfibrillar bonding?.  Wood science. 6 266-271
• 19 Scallan,  A. M.. (1977) The accommodation of water within pulp fibers. Fibre-Water Interactions in Paper-Making. London; Techn. Div. BP & B.I.F. pp. 9-29
• 20 Schwarze,  F. W. M. R., and Engels,  J.. (1998);  Cavity formation and the exposure of peculiar structures in the secondary wall (S₂) of tracheids and fibres by wood degrading Basidiomycetes.  Holzforschung. 52 117-123
• 21 Sell,  J.. (1994);  Confirmation of a sandwich-like model of the cell wall of softwoods by the light microscope.  Holz als Roh- und Werkstoff. 52 234
• 22 Sell,  J., and Zimmermann,  T.. (1993);  Radial fibril agglomerations of the S₂ on transverse fracture surfaces of tracheids of tension-loaded spruce and white fir.  Holz als Roh- und Werkstoff. 51 384
• 23 Sell,  J., and Zimmermann,  T.. (1993) Das Gefüge der Zellwandschicht S₂. Dübendorf; EMPA, Swiss Federal Laboratories for Materials - Building material - wood, 155/28 pp. 26
• 24 Singh,  A. P.. (1996) Ultrastructural features of compression wood cells in relation to bacterial decay in Pinus radiata. . Recent Advances in Wood Anatomy, (1) 1. Donaldson, L. A. et al., eds. Rotorua, New Zealand; New Zealand Forest Research Institute LTD pp. 400-407
• 25 Singh,  A. P., and Daniel,  G.. (2001);  The S₂ layer in the tracheid walls of Picea abies wood: Inhomogeneity in lignin distribution and cell wall microstructure.  Holzforschung. 55 373-378
• 26 Singh,  A. P.,, Sell,  J.,, Schmitt,  U.,, Zimmermann,  T.,, and Dawson,  B.. (1998);  Radial striation of the S₂ layer in mild compression wood tracheids of Pinus radiata. .  Holzforschung. 52 563-566
• 27 Stamm,  A., and Smith,  W.. (1969);  Laminar sorption and swelling theory for wood and cellulose.  Wood Science and Technology. 3 301-323
• 28 Stone,  J. E., and Scallan,  A. M.. (1968);  A structural model for the cell wall of water-swollen wood pulp fibers based on their accessibility to macromolecules.  Cellulose Chemistry and Technology. 2 343-358
• 29 Stone,  J. E.,, Scallan,  A. M.,, and Ahlgren,  P. A. V.. (1971);  The ultrastructural distribution of lignin in tracheid cell walls.  Tappi. 54 1527-1530
• 30 Terashima,  N.,, Fukushima,  K.,, He,  L.-F.,, and Takabe,  K.. (1993) Comprehensive model of the lignified plant cell wall. Forage Cell Wall Structure and Digestibility. Jung, H. G. et al., eds. Madison; American society of agronomy pp. 247-270
• 31 Wardrop,  A. B., and Dadswell,  H. E.. (1950);  The nature of reaction wood: II. The cell wall organization of compression wood tracheids.  Australian Journal of Scientific Research. 3 1-13
• 32 Withcomb,  J. D.. (1979) Experimental and Analytical Study of Fatigue Damage in Notched Graphite/Epoxy Laminates. Fatigue of fibrous composite materials. Wheeler, J. B. et al., eds. Philadelphia; American society for testing and materials pp. 48-63
• 33 Wickholm,  K.,, Larsson,  P. T.,, and Iversen,  T.. (1998);  Assignment of non-crystalline forms in cellulose I by CP/MAS ¹³C NMR spectroscopy.  Carbohydrate Research. 312 123-129
• 34 Zimmermann,  T., and Sell,  J.. (1997) Das Feingefüge der Zellwand auf Querbruchflächen von längszugbeanspruchten Laubhölzern. Dübendorf; EMPA, Swiss Federal Laboratories for Materials - Building material - wood, 115/35 pp. 32
• 35 Zimmermann,  T., and Sell,  J.. (2000) Comparison of the biomechanical properties of the fine structure of the cell wall of normal and reaction wood. Plant Biomechanics. Spatz, H.-C. and Speck, T., eds. Stuttgart; Georg Thieme Verlag pp. 186-192
• 36 Zimmermann,  T.,, Sell,  J.,, and Eckstein,  D.. (1994);  Rasterelektronmikroskopische Untersuchungen an Zugbruchflächen von Fichtenholz.  Holz als Roh- und Werkstoff. 52 223-229
• 37 Åkerholm,  M., and Salmén,  L.. (2001);  Interactions between wood polymers studied by dynamic FT-IR spectroscopy.  Polymer. 42 963-969

Section Editor: A. M. C. Emons