[article]
| Titre : |
Floral dimorphism, pollination, and self-fertilization in gynodioecious Geranium richardsonii (Geraniaceae) |
| Type de document : |
Imprimé |
| Auteurs : |
C.F. Williams ; Margaret A. Kuchenreuther ; A. Drew |
| Année de publication : |
2000 |
| Article en page(s) : |
661-669 |
| Langues : |
Anglais (eng) |
| Catégories : |
[CBNPMP-Thématique] Biologie de la reproduction
[CBNPMP-Thématique] Biologie florale, floraison
|
| Mots-clés : |
Geranium Geranium richardsonii |
| Résumé : |
The selective maintenance of gynodioecy depends on the relative fitness of the male-sterile (female) and hermaphroditic morphs. Females may compensate for their loss of male fitness by reallocating resources from male function (pollen production and pollinator attraction) to female function (seeds and fruits), thus increasing seed production. Females may also benefit from their inability to self-fertilize if selfing and inbreeding depression reduce seed quality in hermaphrodites. We investigated how differences in floral resource allocation (flower size) between female and hermaphroditic plants affect two measures of female reproductive success, pollinator visitation and pollen receipt, in gynodioecious populations of Geranium richardsonii in Colorado. Using emasculation treatments in natural populations, we further examined whether selfing by autogamy and geitonogamy comprises a significant proportion of pollen receipt by hermaphrodites. Flowers of female plants are significantly smaller than those of hermaphrodites. The reduction in allocation to pollinator-attracting structures (petals) is correlated with a significant reduction in pollinator visitation to female flowers in artificial arrays. The reduction in attractiveness is further manifested in significantly less pollen being deposited on the stigmas of female flowers in natural populations. Autogamy is rare in these protandrous flowers, and geitonogamy accounts for most of the difference in pollen receipt between hermaphrodites and females. Female success at receiving pollen was negatively frequency dependent on the relative frequency of females in populations. Thus, two of the prerequisites for the maintenance of females in gynodioecious populations, differences in resource allocation between floral morphs and high selfing rates in hermaphrodites, occur in G. richardsonii. |
| Lien pérenne : |
DOI : 10.2307/2656852  |
| Permalink : |
https://biblio.cbnpmp.fr/index.php?lvl=notice_display&id=137575 |
in American Journal of Botany > 87 (5) (05/2000) . - 661-669
Williams, C.F., Kuchenreuther, Margaret A., Drew, A.
2000
Floral dimorphism, pollination, and self-fertilization in gynodioecious Geranium richardsonii (Geraniaceae).
American Journal of Botany, 87(5): 661-669.
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Affiner la rechercheFloral dimorphism, pollination, and self-fertilization in gynodioecious Geranium richardsonii (Geraniaceae) / C.F. Williams in American Journal of Botany, 87 (5) (05/2000)
ConsultablePollination, breeding system, and genetic structure in two sympatric Delphinium (Ranunculaceae) species / C.F. Williams (2001)
