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Protoplasma

, Volume 221, Issue 3–4, pp 175–184 | Cite as

Localization of sucrose synthase and callose in freeze-substituted secondary-wall-stage cotton fibers

  • Vadim V. Salnikov
  • Mark J. Grimson
  • Robert W. Seagull
  • Candace H. Haigler

Summary.

 Methods for cryogenic fixation, freeze substitution, and embedding were developed to preserve the cellular structure and protein localization of secondary-wall-stage cotton (Gossypium hirsutum L.) fibers accurately for the first time. Perturbation by specimen handling was minimized by freezing fibers still attached to a seed fragment within 2 min after removal of seeds from a boll still attached to the plant. These methods revealed native ultrastructure, including numerous active Golgi bodies, multivesicular bodies, and proplastids. Immunolocalization in the context of accurate structure was accomplished after freeze substitution in acetone only. Quantitation of immunolabeling identified sucrose synthase both near the cortical microtubules and plasma membrane and in a proximal exoplasmic zone about 0.2 μm thick. Immunolabeling also showed that callose (β-1,3-glucan) was codistributed with sucrose synthase within this exoplasmic zone. Similar results were obtained from cultured cotton fibers. The distribution of sucrose synthase is consistent with its having a dual role in cellulose and callose synthesis in secondary-wall-stage cotton fibers.

Keywords: Cell wall; Cellulose synthesis; Cryogenic specimen preparation; Gossypium hirsutum; Immunolabeling; Transmission electron microscopy. 
DPA days post anthesis; SuSy sucrose synthase; P-SuSy particulate sucrose synthase. 

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Copyright information

© Springer-Verlag Wien 2003

Authors and Affiliations

  • Vadim V. Salnikov
    • 1
  • Mark J. Grimson
    • 1
  • Robert W. Seagull
    • 2
  • Candace H. Haigler
    • 1
  1. 1.Department of Biological Sciences, Texas Tech University, Lubbock, TexasUS
  2. 2.Department of Biology, Hofstra University, Hempstead, New TorkUS

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