Pollen presenters in the South African flora
Ladd, P.G. and Donaldson, J.S. (1993) Pollen presenters in the South African flora. South African Journal of Botany, 59 (5). pp. 465-477.
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In contrast with the majority of flowering plants, where pollen is released directly from the anthers to travel to the female organ to effect fertilization, the pollen in certain species belonging to fifteen families worldwide is initially deposited on the female part of the flower before transport to another flower occurs. The structure on which the pollen is deposited is (in almost all cases) a modification of the style called the pollen presenter.
In South Africa, pollen presenters are ubiquitous in the Asteraceae, Campanulaceae, Lobeliaceae, Goodeniaceae and Proteaceae; they also occur in almost half of the genera in the Rubiaceae, and in Polygala and some Muraltia (Polygalaceae), in Turraea, Trichilia and Ekebergia (Meliaceae) and a small proportion of taxa in the Fabaceae. The modifications of the style take various forms and can be summarized into actively and passively operating types. The active forms act like a piston to push the pollen away from the anthers, while the passive forms are static, receiving the pollen from the anthers before the anthers fall away to leave the pollen ready to be removed from the presenter by animals or the wind.
In the past, pollen presenters have either not been recognized or have been described as styles or stigmas. This leads to confusion about processes involved in pollination and wastes useful information which is of value in taxonomic studies.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||School of Biological and Environmental Sciences|
|Publisher:||National Inquiry Services Centre Ltd.|
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