Cosmos pollen ontogeny: A scanning electron microscope study
| ISSN: |
1615-6102
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| Keywords: |
Compositae ; Cosmos bipinnatus ; Freeze-fracture ; Cytoplasmic maceration ; Pollen ontogeny ; Scanning electron microscopy
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| Source: |
Springer Online Journal Archives 1860-2000
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| Topics: |
Biology
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| Notes: |
Summary Ontogenetic data concerning pollen not only clarifies the mode of deposition of the elaborate walls but has considerable functional and taxonomic relevance. Hitherto such studies have used optical or transmission electron microscopy but here a recently devised preparative technique has enabled pollen development inCosmos bipinnatus to be studied using the scanning electron microscope. The technique involves freeze-fracturing of osmium fixed, cryoprotected anthers, maceration in dilute osmium tetroxide, critical point drying, sputter coating and examination. The processes of pollen wall development can then be observed in three dimensions, an important aid to understanding the spatial relationships involved in the determination of ornamentation and apertures. Details of the pollen and tapetum are described at various stages between meiosis and anthesis. A close conformity is demonstrated between the results obtained and those of earlier transmission electron microscopic studies of the same and related species although very different interpretations are made.
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| Type of Medium: |
Electronic Resource
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| URL: |