Letter | Published:

Secondary Walls in Phloem of Pinus radiata D. Don

Naturevolume 207pages657658 (1965) | Download Citation



Abbe and Crafts1 showed that the development of secondary walls in the sieve cells of gymnosperms is apparently restricted to the Abietineae; there is no evidence of secondary wall in the sieve cells of Taxodineae, Araucarineae, Cupressineae and Taxineae. Moreover, the Abietineae develop no fibres, but the secondary walls of their sieve cells appear to be composed of relatively pure cellulose. Secondary walls occur in the sieve cells of white pine, Pinus strobus L. (Figs. 3 and 24 in ref. 1).

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  1. 1

    Abbe, L. B., and Crafts, A. S., Bot. Gaz., 100, 695 (1939).

  2. 2

    Barghoorn, E. S., and Scott, R. A., Amer. J. Bot., 45, 222 (1958).

  3. 3

    Johansen, D. A., Plant Micro-Technique (McGraw-Hill Book Co., New York and London, 1940).

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  1. School of Biological Sciences, University of Sydney, Australia

    • A. MAHMOOD


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