Floral elaiophores in Lockhartia Hook. (Orchidaceae: Oncidiinae): their distribution, diversity and anatomy

Abstract

All species of Lockhartia investigated have trichomal elaiophores on the adaxial surface of the labellum. Histochemical tests revealed the presence of lipoidal substances within the labellar trichomes. However, the degree of oil production and the distribution of trichomes differed between the three major groups of species found within the genus. All trichomes were unicellular and, in some species, of two distinct sizes, the larger being either capitate or apically branched. The trichomal cuticle was lamellate, and often appeared distended due to the subcuticular accumulation of oil. The labellar trichomes of the three species examined using transmission electron microscopy contained dense, intensely staining cytoplasm with apically located vacuoles. Oil-laden secretory vesicles fused with the plasmalemma and discharged their contents. Oil eventually accumulated between the cell wall and cuticle of the trichome and contained electron-transparent profiles or droplets. This condition is considered unique to Lockhartia among those species of elaiophore-bearing Oncidiinae studied to date.

<em>Zygostates alleniana</em> (Orchidaceae: Epidendroideae: Cymbidieae: Oncidiinae): estructura floral relacionada con la polinización

“…Diversos estudios han demostrado que dentro de la subtribu Oncidiinae los elaióforos epiteliales son los más comunes (Singer & Cocucci, 1999;Reis & al., 2006;Stpiczyńska & Davies, 2008;Pacek & Stpiczyńska, 2007;Aliscioni & al., 2009;Pansarin & Pansarin, 2010, Pacek & al., 2012Gómiz & al., 2013); en menor medida se registraron elaióforos tricomáticos para los géneros Lockhartia, Ornithocephalus, Phymatidium y Zygostates (Vogel, 1974;Buchmann, 1987;Toscano de Brito, 2001;Reis & al., 2006;Pacek & Stpiczyńska, 2007;Pacek & al., 2012, Blanco & al., 2013. Pacek & al.…”

Elaiophores: their taxonomic distribution, morphology and functions

“…The trichomes can be concentrated on the base of the staminal column, on the base of the inner surface of the tepals or along the middle vein of each tepal (Vogel 1974;Goldblatt et al1998;Cocucci & Vogel 2001;Chaveau et al 2011;2012;Silvério et al 2012;see Tab.2 Vogel 1974;Singer & Cocucci 1999;Alves-dos-Santos et al 2002;Reis et al 2003;Reis et al 2006;Pacek & Stpiczyńska 2007;Stpiczyńska et al 2007;Aliscioni et al 2009;Pansarin & Pansarin 2011;Torretta et al 2011;Neubig et al 2012;Pacek et al 2012;Blanco et al 2013 Orchidoideae Cranichideae…”

“…Trichomal elaiophores are generally constituted by a set of unicellular hairs which may occupy one or two distinct areas (Vogel 1974;Pacek & Stpiczyńska 2007;Pansarin et al 2009;Pacek et al 2012;Blanco et al 2013;Gomiz et al 2014). The trichomes can be either short (Pansarin et al 2009;Pacek et al 2012;Blanco et al 2013) or elongated (Vogel 1974;Pacek & Stpiczyńska 2007;Pansarin et al 2009;Pansarin & Pansarin 2011;Pacek et al2012;Blanco et al 2013;Gomiz et al 2014). These unicellular trichomes have uniform width in most species but are capitate in Phymatidium falcifolium (Pacek et al 2012).…”

“…These unicellular trichomes have uniform width in most species but are capitate in Phymatidium falcifolium (Pacek et al 2012). In Lochartia species they can be capitate, bifid or branched at the apex (Blanco et al 2013).…”

The uncommon cavitated secretory trichomes inBauhinia s.s.(Fabaceae): the same roles in different organs

“…(Scrophulariaceae) and Lockhartia Hook. (Orchidaceae), the trichomes on petals produce non‐volatile oils (Vogel & Machado, ; Blanco et al ., ); and in Anadenanthera peregrina (L.) Speg. (Fabaceae), the petal secretory trichomes produce volatiles (Marinho et al ., ).…”