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Microsporogenesis and Cytokinesis in Asimina triloba

1936; University of Chicago Press; Volume: 98; Issue: 1 Linguagem: Inglês

10.1086/334624

1940-1205

John Flowers Locke,

Plant Reproductive Biology

1. During meiosis the chromatin material of the pollen mother cells undergoes parasynaptic association. 2. At synizesis the chromatic knot lies on the side of the nucleus farthest from the mother cell wall. 3. The haploid number of chromosomes is apparently nine. 4. Cytokinesis of the pollen mother cells is by successive constriction. Evanescent cell plates may occur in the first division. 5. In general the first cytoplasmic division is completed before the second nuclear divisions occur. 6. In the second cytoplasmic division the furrow appears first on the side of the daughter cells adjacent to the wall of the first division, and proceeds outward for a time before it appears at the outer periphery of the cell. 7. The young microspores are relatively small and have a quadrilateral arrangement as a result of the spindles of the second division being perpendicular to the axis of the first division and in the same plane with it. 8. Before being shed, the microspores develop into relatively large binucleate microgametophytes which are completely filled with dense, alveola-like cytoplasm.