Article

Pollination biology of cantharophilous and melittophilous Annonaceae and Cyclanthaceae in French Guiana

01/2008;
Source: OAI

ABSTRACT

Due to human impact tropical forests become fragmented and their preservation and sustainable management receive more attention. Functioning plant-animal interactions are crucial for long-term preservation of biodiversity in every rainforest. Therefore, understanding the plant-animal interactions is the key to sustainable management of this ecosystem. In undisturbed ecosystems, these interactions exist in their most preserved state and provide the true account on the ecology of the species concerned. The relationship between plants and their insect pollinators is one of the most important interactions in the evolutionary history of angiosperms. Most tropical plants are pollinated by insects, but only a fraction has been investigated and information is completely missing for many evolutionary important taxonomical groups. The aim of the present study was to estimate pollination mechanisms of selected species belonging to the families Annonaceae and Cyclanthaceae in their original and undisturbed habitat. Annonaceae are an evolutionary old family, and their members form an important component of tropical rainforests because of their species richness and high abundance. The Cyclanthaceae occur only in the Neotropics. Their live form include mostly terrestrial herbs or (hemi)-epiphytes.

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    • "Its floral odor is dominated by compounds indicative of fermenting sugar (2-and 4-carbon aliphatic alcohols, acetic acid and 3-hydroxy-2-butanone), and is perceived by humans as 'yeasty'. The unusual floral scent of A. triloba differs from the fruity alcohol-and ester-dominated scents of tropical Annonaceae studied by Jürgens et al. (2000) and Teichert (2008), and from the unusual floral volatiles of Unonopsis stipitata and Duguetia cadaverica, which attract male euglossine bees and mycetophagous beetles, respectively (Teichert, 2008; Teichert et al., 2008). These 'yeasty' 2-and 4-carbon aliphatic compounds may attract a broader spectrum of saprophilic insects from several orders (see Willson & Schemske, 1980) through generalized mimicry of fermented fruit or sap. "
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    ABSTRACT: Floral scent is a key component of floral display, and probably one of the first floral attractants linking insect pollinators to the radiation of Angiosperms. In this article, we investigate floral scent in two extra-tropical genera of Annonaceae. We discuss floral scent in the context of differing pollination strategies in these genera, and compare their scent to that of a close tropical relative. Floral volatiles were collected for Annona glabra, Asimina and Deeringothamnus whole flowers and dissected floral organs, using a standardized static-headspace solid phase microextraction method. Scents were analyzed using gas chromatography-mass spectrometry, and identified using known standards. The floral scents of these species are highly dynamic, varying between floral organs, sexual stages and species. Maroon-flowered species of Asimina produce 'yeasty' odors, dominated by fermentation volatiles and occasionally containing sulfurous or nitrogenous compounds. White-flowered species of Asimina and Deeringothamnus produce pleasant odors characterized by lilac compounds, benzenoids and hydrocarbons. Annona glabra produces a strong, fruity-acetonic scent dominated by 3-pentanyl acetate and 1,8-cineole. The fermented/decaying scents of maroon-flowered species of Asimina suggest mimicry-based pollination strategies similar to aroids and stapeliads, whereas the pleasant scents of white-flowered species of Asimina suggest honest, reward-based pollination strategies. The scent of Annona glabra is typical of specialized beetle pollination systems common to tropical Annonaceae.
    Full-text · Article · Feb 2009 · New Phytologist
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    Full-text · Article · Feb 2009 · New Phytologist
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    ABSTRACT: Breeding system and pollination biology of an isolated population of Cymbopetalum brasiliense (Annonaceae), a large-flowered understory tree, was studied during two consecutive flowering seasons in October/November 2007 and September/October 2008. Flowers were morphologically comparable to other Cymbopetalum species and generally to other Annonaceae taxa adapted to pollination by large beetles, such as Annona spp. Flowers were thermogenic and emitted a strong scent during the pistillate and staminate flowering phases. Heating of the floral chamber was most intense during the pistillate phase between 1800 and 1900h (up to 6°C difference to air temperature). Floral scent consisted almost entirely of p-methylanisole. None of the 133 flowers examined during two seasons received any visitation by dynastid beetles or other potential pollinators. Lycaenid larvae (Oenomaus ortygnus) attacked buds and flowers in both flowering seasons and destroyed about 20% of all buds in the 2007 season. Fruit set was high (72% of nonpredated flowers in 2007), despite the absence of pollinators. Field experiments showed that agamospermic reproduction rather than self-pollination was most likely responsible for fruit production. The study reports a probable case of apomixis, which would be the first in the Annonaceae family. KeywordsAbsence of pollinators–Apomixis–Atlantic forest– Cymbopetalum brasiliense – p-Methylanisole–Thermogenesis
    No preview · Article · Oct 2011 · Plant Systematics and Evolution
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