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This article in CS

  1. Vol. 46 No. 4, p. 1793-1800
    Received: Feb 8, 2006

    * Corresponding author(s): jungx002@umn.edu
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Maize Stem Tissues

  1. H. G. Jung *a and
  2. M. D. Caslerb
  1. a USDA-ARS Plant Science Res. Unit and U.S. Dairy Forage Res. Center Cluster, Univ. of Minnesota, Dep. of Agronomy and Plant Genetics, 411 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108
    b USDA-ARS U.S. Dairy Forage Res., 1925 Linden Drive West, Madison, WI 53706


Grass maturation results in reduced cell wall degradability by ruminant livestock. Using a specific internode of maize (Zea mays L.) stems as a model, the pattern of grass stem tissue and cell wall development was characterized. The fourth elongated internode above ground level from three maize hybrids was sampled at 10 stages of development beginning when the internode was about 10 mm in length through physiological maturity from a 2-yr, replicated field trial at St. Paul, MN. Tissue development was characterized by light microscopy. Cell wall concentration and composition (polysaccharide sugar residues, lignin, ferulates, and p-coumarates) were determined. Internode length and cross-sectional area increased from Sampling Date 1 until the interval between Sampling Dates 5 and 6. During elongation only protoxylem vessels stained positive for lignin. After elongation, parenchyma, sclerenchyma, and metaxylem tissues lignified, but phloem did not. Cell wall concentration increased until shortly after elongation ended. Cell wall lignin concentration declined over the first four samples, with an increase in glucose and xylose polysaccharide residues, before rising sharply until after elongation was complete. Ferulate cross-links of lignin to arabinoxylan increased 12-fold during elongation. Our results indicated that post-elongation development of sclerenchyma and rind-region parenchyma accounted for the majority of cell wall accumulation and lignification in maize stems.

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Copyright © 2006. Crop Science Society of AmericaCrop Science Society of America