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Striped projections of the outer membrane of the generative cell in Convallaria majalis pollen

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In pollen grains of Convallaria majalis the outer membrane of the generative cell (GC) is the inner membrane of the vegetative cell (VC). Striped projections (SP) at the cytoplasmic face of the outer membrane of the GC were revealed by chemical fixation and also by a rapid freeze-fixation and freeze-substitution. The projections, located in groups on the protruding lobes of the GC, were arranged parallel to each other and were equally spaced (40 nm apart). The length of the SP, estimated from grazing sections of GC, was 400 nm. Each projection was composed of T-shaped elements, about 35 nm high, spaced at an average distance of 25 nm. SP were observed in mature, hydrated, activated and germinated pollen grains and seemed to be associated with microtubules and microfilaments of the VC. No evidence exists yet of SP on the sperm cell membrane. Immunogold labelling with anti-myosin antibodies showed many gold particles attached preferentially to the surface of the protruding lobes of the GC in the area of the projections. These results may suggest that the SP of Convallaria GC contain myosin-like protein and play an important role in the motility of the GC during pollen tube growth.

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  1. Brewbaker JL, Kwack BH (1963) The essential role of calcium ion on pollen germination and pollen tube growth. Am J Bot 50:859–865

  2. Cresti M, Lancelle SA, Hepler PK (1987) The structure of the generative cell wall complex after freeze-substitution in pollen tubes of Nicotiana and Impatiens. J Cell Sci 88:373–378

  3. Cresti M, Murgia M, Theunis CH (1990) Microtubule organization in sperm cells in the pollen tube of Brassica oleracea L. Protoplasma 154:151–156

  4. Cresti M, Ciampolini F, Van Went JL (1991) Strip-shaped projections at the cytoplasmic face of the outer membrane of the generative cell in Amaryllis belladonna. Ann Bot 68:105–107

  5. Heslop-Harrison J, Heslop-Harrison Y (1989a) Myosin associated with the surfaces of organelles, vegetative nuclei and generative cells in angiosperm pollen grains and tubes. J Cell Sci 94: 319–325

  6. Heslop-Harrison J, Heslop-Harrison Y (1989b) Cytochalasin effects on structure and movement in the pollen tube of Iris. Sex Plant Reprod 2:7–37

  7. Heslop-Harrison J, Heslop-Harrison Y (1989c) Actomyosin and movement in the angiosperm pollen tube: an interpretation of some recent results. Sex Plant Reprod 2:199–207

  8. Hess MW (1993) Membrane coatings on the generative cell surface of freeze-substituted monocotyledon pollen. Protoplasma 176:84–88

  9. Lancelle SA, Hepler PK (1992) Ultrastructure of freeze-substituted pollen tubes of Lilium longiflorum. Protoplasma 167: 215–230

  10. Lancelle SA, Cresti M, Hepler PK (1987) Ultrastructure of the cytoskeleton in freeze-substituted pollen tubes of Nicotiana alata. Protoplasma 140:141–150

  11. Palevitz BA, Liu B (1992) Microfilaments (F-actin) in generative cell and sperm: an evaluation. Sex Plant Reprod 5:89–100

  12. Palevitz BA, Tiezzi A (1992) The organization, composition, and function of the generative cell and sperm cytoskeleton. Int Rev Cytol 140:149–185

  13. Pierson ES, Cresti M (1992) Cytoskeleton and cytoplasmic organization of pollen and pollen tubes. Int Rev Cytol 140:73–125

  14. Spurr AR (1969) A low-viscosity epoxy resin embedding medium for electron microscopy. J Ultrastruct Res 26:31–43

  15. Tang H, Hepler PK, Scordilis SP (1989) Immunochemical and immunocytochemical identification of a myosin heavy chain polypeptide in Nicotiana pollen tubes. J Cell Sci 92:569–574

  16. Tiezzi A, Moscatelli A, Cai G, Bartalesi A, Cresti M (1992) An immunoreactive homologue of mammalian kinesin in Nicotiana pollen tube. Cell Motil Cytoskeleton 21:132–137

  17. Van Went J, Gori P (1989) The ultrastructure of Capparis spinosa pollen grain. J Submicrosc Cytol Pathol 21:149–156

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Bohdanowicz, J., Ciampolini, F. & Cresti, M. Striped projections of the outer membrane of the generative cell in Convallaria majalis pollen. Sexual Plant Reprod 8, 223–227 (1995). https://doi.org/10.1007/BF00228941

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Key words

  • Pollen
  • Generative cell
  • Cytoskeleton
  • Motility
  • Myosin immunogold labelling