Anatomy of the floral nectary of ornithophilous Elleanthus brasiliensis (Lindl.) Rchb.f. (Orchidaceae: Sobralieae).

NUNES CEP; CASTRO MM; GALETTO L; SAZIMA M

BOTANICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2012 vol. 171

0024-4074

Orchidaceae show enormous floral diversity. However, anatomical studies of nectary tissues relative to nectarcomposition and pollinators are scarce. This work aims to present a detailed anatomical study of the labellarnectary of Elleanthus brasiliensis, analyse the chemical composition of its nectar and relate these findingsto pollination biology. Basally, the labellum bears a pair of fleshy, whitish, ovoid calli on its adaxial surface.Nectariferous callus tissue consists of a papillate epidermis and enlarged, subepidermal parenchyma cells with thinwalls, large nuclei and dense cytoplasm which stained positively for hydrophilic substances, interpreted aspre-nectar. The paired calli lack vascular tissues, but at the point of callus insertion, the diameters of vascularbundles supplying the lip are larger. Nectar is secreted as droplets on the adaxial callus surface. It is produced insmall quantities, c. 4 mL per flower. Callus cell contents tested negative for polysaccharides, lipids and phenoliccompounds. The nectar is sucrose-dominant, as in other hummingbird-pollinated species. It is suggested that otherornithophilous species of Sobralieae have anatomically similar nectaries. © 2013 The Linnean Society of London,Botanical Journal of the Linnean Society, 2013, ••, ••–••.