Summary
In mature tricellular pollen of rapeseed,Brassica campestris L., the pair of sperm cells are held together within the common plasma membrane of the vegetative cell and are closely associated with the vegetative nucleus. Serial thin sections were cut of entire sperm cell associations of 7 pollen grains, and 3-dimensional coordinated information obtained by digitization. Precise lengths and placement of the sperm cells and vegetative nucleus in three dimensions were computed and stereoscopic images generated and confirmed by two manually constructed 3-dimensional models. The sperm cell most closely associated with the vegetative nucleus, possessed a long tail, > 10 Μm in length, that penetrated through a passage in the highly convoluted nucleus. This long tail contained a forked array of microtubules in all 7 grains examined. Arrays of microtubules occurred in the second sperm cell, aligned within plasma-membrane evaginations or ridges.
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McConchie, C.A., Jobson, S. & Knox, R.B. Computer-assisted reconstruction of the male germ unit in pollen ofBrassica campestris . Protoplasma 127, 57–63 (1985). https://doi.org/10.1007/BF01273701
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DOI: https://doi.org/10.1007/BF01273701