Ultrastructural Observations of Parenchyma and Sclereids in Douglas-Fir (<i>Pseudotsuga Menziesh</i> (MIRB.) FRANCO) Bark

Authors

  • Edward F. Dougal
  • Robert L. Krahmer

Keywords:

Bark, Douglas-fir, anatomy, ultrastructure

Abstract

Pitting that occurs in sclereids and parenchyma cells of Douglas-fir bark was examined, along with differences in structure of cell walls in parenchyma from inner and outer bark. Axial parenchyma is connected by pit areas that appear as a slightly thinner region in the adjacent walls where plasmodesmata are found. Sclereid-to-parenchyma pitting consists of a long pit canal through the sclereid wall about 1 μm in diameter with little or no evidence of a pit chamber. The pit membrane is the original double cell wall of the parenchyma as found in parenchyma-to-parenchyma pitting. Pitting between two sclereids exhibits similar long pit canals through the selereid walls, but a pit chamber is present with a thick membrane likewise consisting of the double cell wall of the parenchyma. During sclereid formation the secondary wall of the sclereid appears to be deposited by apposition on the original parenchyma cell wall. Parenchyma cells in inner bark have small wrinkles and folds in the cell wall, whereas enlarged parenchyma in outer bark have very smooth walls.

References

Beriyn, G. P. 1963. Methacrylate as an embedding medium for woody tissues. Stain Technol.38:23-28.nBramhill, A. E., and R. N. Kellogg. 1979. Anatomy of secondary phloem of western hemlock, Tsuga heterophylla (RAF) Sarg. Internat. Assoc. Wood Anat. Bull.4:79-85.nChang, Y. 1954. Anatomy of common North American conifers. U.S. Dep. Agric. Tech. Bull. 1095. Washington, DC.nCôté, W. A., and C. deZeeuw. 1962. Trends in literature on wood structure. For. Prod. J.12(4):203-212.nCôté, W. A., Z. Koran, and A. C. Day. 1964. Replica techniques for electron microscopy of wood and pulp. Tappi47(8):477-484.nDen Outer, R. W. 1967. Histological investigations of the secondary phloem of gymnosperms. H. Veenman & Zonen N.V., Wageningen.nDougal, E. F. 1981. Ultrastructure of parenchyma and sclereids in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) bark. Ph.D. thesis, Oregon State University, Corvallis, OR.nEsau, K. 1969. The phloem. Gebrüder Bornträger, Berlin and Stuttgart.nGoldschmid, O., and M. W. Folsom. 1975. A note on the appearance of sclereids from western hemlock inner bark. Wood Fiber7(2):146-148.nGrillos, S. J., and F. H. Smith. 1959. The secondary phloem of Douglas-fir. For. Sci.5:377-388.nHall, J. A. 1971. Utilization of Douglas-fir bark. USDA For. Serv., Pac. Northwest For. & Range Exp. Stn., Portland, OR.nLitvay, J. D., and R. L. Krahmer. 1977. Wall layering in Douglas-fir cork cells. Wood Fiber9(4):167-173.nMia, A. J. 1969. Study of cell walls in angiospermous plants using light and electron microscopes. Wood Sci.2(1):1-10.nMiller, D. J., R. L. Krahmer, J. D. Wellons, and P. Short. 1974. Reinforcing plastics with Douglas-fir bark fiber. For. Prod. J.24(8):18-23.nMurmanis, L., and R. F. Evert. 1967. Parenchyma cells of secondary phloem in Pinus strobus. Planta (Berl.)73:301-318.nNanko, H., and W. A. Côté. 1980. Bark structure of hardwoods grown on southern pine sites. Syracuse University Press, Syracuse, NY.nNanko, H., H. Saiki, and H. Harada. 1978. Cell wall structure of the sclereids in the secondary phloem of Populus euramericana. Mokuzai Gakkaishi24(6):362-368.nPatel, N. R. 1975. Bark anatomy of radiata pine, Corsican pine and Douglas-fir grown in New Zealand. N.Z. J. Bot.13:149-167.nPease, D. C. 1960. Histological techniques for electron microscopy. Academic Press, NY.nRoss, W. D., and R. L. Krahmer. 1971. Some sources of variation in structural characteristics of Douglas-fir bark. Wood Fiber3(1):35-46.nSpurr, A. T. 1969. A low viscosity epoxy resin embedding medium for electron microscopy. J. Ultrastruct. Res.26:31-43.nTucker, M. C., and R. F. Evert. 1969. Seasonal development of the secondary phloem of Acer negundo. Am. J. Bot.56(3):275-284.nWebb, M. A., and H. J. Arnott. 1982. Cell wall conformation in dry seeds in relation to the preservation of structural integrity during desiccation. Am. J. Bot.69(10):1657-1668.nWellons, J. D., and R. L. Krahmer. 1973. Self bonding in bark composites. Wood Sci.6(2):112-122.nYie-Hsiang, L. L. 1975. Anatomy of chemically and mechanically isolated bark sclereids. M.S. thesis, Oregon State University, Corvallis, OR.n

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Published

2007-06-27

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Research Contributions