AOBPreview originally published online on December 1, 2007
Annals of Botany 2008 101(3):375-384; doi:10.1093/aob/mcm297
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elaiophore Structure and Oil Secretion in Flowers of Oncidium trulliferum Lindl. and Ornithophora radicans (Rchb.f.) Garay & Pabst (Oncidiinae: Orchidaceae)
ska1
1 Department of Botany, Agricultural University, Akademicka 15, 20-950 Lublin, Poland
2 School of Earth, Ocean and Planetary Sciences, Cardiff University, PO Box 914, Park Place, Cardiff CF10 3YE, UK
* For correspondence. E-mail kevinldavies{at}btinternet.com
Received: 17 September 2007 Returned for revision: 17 October 2007 Accepted: 24 October 2007 Published electronically: 1 December 2007
Background and Aims: Many orchid flowers have glands called elaiophores and these reward pollinating insects with oil. In contrast to other reward-producing structures such as nectaries, the anatomy of the elaiophore and the process of oil secretion have not been extensively studied. In this paper, elaiophore structure is described for two members of Oncidiinae, Oncidium trulliferum Lindl. and Ornithophora radicans (Rchb.f.) Garay & Pabst.
Methods: Elaiophores of both species were examined using light microscopy, scanning electron microscopy and transmission electron microscopy.
Key Results and Conclusions: In flowers of Oncidium trulliferum and Ornithophora radicans, oil is secreted by morphologically distinct elaiophores associated with the labellar callus. However, in O. trulliferum, elaiophores also occur on the lateral lobes of the labellum. In both these species, the epithelial elaiophores are composed of a single layer of palisade-like epidermal cells and a distinct subepithelial layer. Secretory elaiophore cells may contain numerous, starchless plastids, mitochondria and smooth endoplasmic reticulum profiles. In O. trulliferum, the cytoplasm contains myelin-like figures but these are absent from O. radicans. In the former species, cavities occur in the cell wall and these presumably facilitate the passage of oil onto the elaiophore surface. In O. radicans, the accumulation of oil between the outer tangential wall and the cuticle causes the latter to become distended. Since it is probable that the full discharge of oil from the elaiophores of O. radicans occurs only when the cuticle is ruptured by a visiting insect, this may contribute towards pollinator specificity. The structure of the elaiophore in these species resembles both that found in previously investigated species of Oncidiinae and that of certain members of the Malpighiaceae.
Key words: Elaiophore, Oncidium trulliferum, Ornithophora radicans, Orchidaceae, oil secretion, pollination
CiteULike 
Connotea 
Del.icio.us What's this?
Related articles in Ann Bot:
- ContentSnapshots
Ann Bot 2008 101: NP.[Extract] [Full Text]
This article has been cited by other articles:
|
|
 |
|
  S. S. Renner and H. Schaefer The evolution and loss of oil-offering flowers: new insights from dated phylogenies for angiosperms and bees Phil Trans R Soc B, February 12, 2010; 365(1539): 423 - 435. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. S. Aliscioni, J. P. Torretta, M. E. Bello, and B. G. Galati Elaiophores in Gomesa bifolia (Sims) M.W. Chase & N.H. Williams (Oncidiinae: Cymbidieae: Orchidaceae): structure and oil secretion Ann. Bot., November 1, 2009; 104(6): 1141 - 1149. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. L. Davies and M. Stpiczynska Comparative histology of floral elaiophores in the orchids Rudolfiella picta (Schltr.) Hoehne (Maxillariinae sensu lato) and Oncidium ornithorhynchum H.B.K. (Oncidiinae sensu lato) Ann. Bot., August 1, 2009; 104(2): 221 - 234. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Compiled by, F. Tooke, T. Chiurugwi, and N. Battey Flowering Newsletter bibliography for 2008 J. Exp. Bot., June 23, 2009; (2009) erp154v1. [Full Text] [PDF]
|
|