Osmophore and elaiophores of Grobya amherstiae (Catasetinae, Orchidaceae) and their relation to pollination

Authors

  • LUDMILA MICKELIUNAS PANSARIN,

    Corresponding author
    1. Pós-Graduação em Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas, CP 6109, Campinas, SP, 13083-970, Brasil
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  • MARILIA DE MORAES CASTRO,

    1. Departamento de Botânica, Instituto de Biologia, Universidade Estadual de Campinas, CP 6109, Campinas, SP, 13083-970, Brasil
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  • MARLIES SAZIMA

    1. Departamento de Botânica, Instituto de Biologia, Universidade Estadual de Campinas, CP 6109, Campinas, SP, 13083-970, Brasil
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*E-mail: colax@pop.com.br

Abstract

Grobya amherstiae flowers release a honey-like scent produced by an osmophore, comprising a papillate epidermis. The scent attracts bee pollinators (Paratetrapedia fervida), which collect floral oils produced by elaiophores on the lip apex and column base. The secretory tissue of the elaiophore on the lip apex consists of both palisade-like epidermal cells and conspicuously elongated unicellular trichomes. From an anatomical point of view, this elaiophore differs in structure from those known in angiosperms to date. The elaiophore on the column base is exclusively composed of short unicellular trichomes. In addition, there is an elaiophore comprising a papillate epidermis on the internal surface of the lip. The elaiophores produce a heterogeneous secretion, composed of fatty acids and mucilage. The elaiophore on the internal surface of the lip produces oil in non-collectible amounts, but it is enough to maintain the interest of the bees, guiding them to the elaiophore on the column base, a necessary step in pollination. The former elaiophore is here identified as an oil guide and it plays an essential role in ensuring pollination. The presence of three types of elaiophores on the flowers of this species of Orchidaceae is peculiar and noteworthy. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 159, 408–415.

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