The Ultrastructure Of Southern Pine Bordered Pit Membranes As Revealed By Specialized Drying Techniques
Abstract
The study of the mature bordered pit membrane from three species revealed that there were no major differences in ultrastructure. The pit membrane consists of an imperforated torus and a margo with considerable variation in porosity. Springwood pit membranes from the sapwood were rarely incrusted, whereas summerwood pit membranes from both the sapwood and heartwood were heavily incrusted.
The use of specialized drying techniques, specifically solvent-exchange, critical-point, and freeze-drying techniques, prevented pit aspiration and permitted a detailed study of the pit membrane. Since the margo structure was not altered to any substantial degree by the different drying systems, it appears that the surface tension of the evaporating liquid is important only with regard to pit aspiration. A study of trees from several age classes showed the decrease of the number of margo microfibrils to be related to the age of the wood rather than to the time of formation. The mechanism of the deterioration process was not determined.
References
Anderson, T. F. 1951. Techniques for the preservation of three-dimensional structure in preparing specimens for the electron microscope. N. Y. Acad. Sci., 13: 130-134.nAnderson, T. F. 1953. A method for eliminating gross artifacts in drying specimens. Compt. Rend. Prem. Congr. Int. Microscop. Electron. Section, 5: 567-576.nBailey, I. W. 1913. The preservative treatment of wood. II. The structure of the pit membranes in the tracheids of conifers and their relation to the penetration of gases, liquids, and finely divided solids into green and seasoned wood. Forest Quart., 11: 12-20.nCôté, W. A., Jr. 1958. Electron microscopic studies of pit membrane structure. Implications in seasoning and preservation of wood. Forest Prod. J., 8(10): 296-300.nCôté, W. A., Jr., Z. Koran, and A. K. Day. 1964. Replica techniques for electron microscopy of wood and paper. TAPPI, 47(8): 477-484.nCronshaw, J. 1965. Cytoplasmic fine structure and cell wall development in differentiating xylem elements. In: W. A. Côté [ed.], Cellular ultrastructure of woody plants. Syracuse University Press, Syracuse, N. Y., S.99.nFengel, D. 1966. Entwicklung und ultrastruktur der Pinaceenhoftüpfel. Svensk Papperstidning, 69(7): 232-241.nFhey-Wyssling, A., H. H. Bosshard, and K. Muhlethaler. 1956. Die submikroskopische entwicklung der hoftüpfel. Planta, 47: 115-126.nFhey-Wyssling, A., K. Muhlethaler, and H. H. Bosshard. 1959. The microscopical resolution of the torus strands in bordered pits. Holzforschung and Holz-Verwertung (11)5. Translation by C. Hiller. Forest Prod. Lab., Madison, Wis.nHarada, H. 1956. Electron microscopic study of wood tissue with special reference to wart-like and bordered pit structures. Trans. 65th Mtg. Jap. Forest. Soc., 31(4): 1-8.nHart, C. A., and R. J. Thomas. 1967. Mechanism of bordered pit aspiration as caused by capillarity. Forest Prod. J., 17(11): 61-68.nKoran, Z. 1964. Air permeability and creosote retention of Douglas-fir. Forest Prod. J., 12(9): 437-442.nKozlowski, T. T., J. F. Hughes, and L. Layton. 1966. Patterns of water movement in dormant gymnosperm seedlings. Biorheology, 3: 77-85.nKrahmer, R. L., and W. A. Côté, Jr. 1963. Changes in coniferous wood cells associated with heartwood formation. TAPPI, 46(1): 42-49.nLiese, W., and M. Fahnenbrock. 1952. Elektronenmikroskopische untersuchungen über den bau der hoftiipfel. Holz als Rohund Werkstoff, 10: 197-201.nLiese, W. 1965. Fine structure of bordered pits in softwoods. In: W. A. Côté, Jr. [ed.], Cellular ultrastructure of woody plants. Syracuse University Press, 271-290.nNicholas, D. D. 1966. Structure and chemical composition of the pit membrane in relation to the permeability of loblolly pine. Ph.D. Dissertation, North Carolina State University at Raleigh, Raleigh, North Carolina.nSebastian, L. P., W. A. Côté, and C. Skaar. 1965. Relationship of gas phase permeability to ultrastructure of white spruce wood. Forest Prod. J., 15(9): 394-404.nThomas, R. J., and D. D. Nicholas. 1966. Pit membrane structure in loblolly pine as influenced by solvent-exchange drying. Forest Prod. J., 16(3): 53-56.nThomas, R. J. 1967. The development and ultrastructure of the pits of two southern yellow pine species. D. F. Dissertation, Duke University, Durham, North Carolina.nThomas, R. J. 1967a. The structure of the pit membranes in longleaf pine: an electron microscope study. Proc. Amer. Wood Preserv. Ass., 63: 20-29.nThomas, R. J. 1968. The development and ultrastructure of the bordered pit membrane in the southern yellow pines. Holzforschung, 22(2): 38-44.nThomas, R. J. 1969. The ultrastructure of the ray tracheid bordered pit membranes in southern pine. In press.n
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