A reduced, yet functional, nectary disk integrates a complex system of floral nectar secretion in the genus Zeyheria (Bignoniaceae)

Autor(es)

Machado, Silvia Rodrigues ; de Souza, Camila Vaz ; Guimaraes, Elza

• Tipo de documento: Artigo Científico
• Fonte: Acta Botanica Brasilica; v. 31, n. 3, p. 344-357, JUL-SEP 2017.
• Citações Web of Science: 4

Resumo

ABSTRACT The genus Zeyheria (Bignoniaceae) comprises only two species, both of which have been described as possessing a reduced and non-functional nectary disk. Despite the importance of this evolutionary change in the floral nectary, these functional assumptions have been based on disk size and on the distribution, abundance and histochemistry of corolla-borne trichomes. By combining methods on light and electron microscopy, here we investigated the functionality of the reduced nectary disk and describe all of the tissues and structures of the nectar chamber in order to determine the sites of floral nectar secretion in both Zeyheria species. . Our data find the floral nectary traits of both species to be very similar, although differing in their cellular contents. Subcellular evidence in both species indicated that disk, stipe and petal axils were, predominantly, involved in hydrophilic secretion, while capitate glandular trichomes produced lipophilic secretion and papillae produced mixed secretion. Our study shows that in spite of its reduced size, the reduced disk functions in nectar secretion in both species of Zeyheria. This kind of nectary system is a novelty for Bignoniaceae, since it comprises several tissues and structures functioning in an integrated fashion. (AU)

• Processo FAPESP: 09/17611-7 - Glândulas florais e interações com polinizadores em Bignoniaceae de cerrado
• Beneficiário: Elza Maria Guimarães Santos
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 08/55434-7 - Estruturas secretoras em espécies vegetais de cerrado: abordagens morfológica, química e ecológica
• Beneficiário: Silvia Rodrigues Machado
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático