Structure and distribution of glandular trichomes in three species of Bignoniaceae

Abstract

Glandular trichomes play a major role in the morphological characterization of the Bignoniaceae. Due to their great diversity of forms and functions, this study aimed to inventory the glandular trichomes present in the aerial vegetative axis of Amphilophium magnoliifolium, Martinella obovata and Stizophyllum riparium, analyze their structure and register the participation of ants in these plants. Fresh samples from the nodal region, petiole and from medium to apical regions of the leaflet blade were fixed and processed according to usual methods in light and scanning electron microscopies. The glandular trichomes found were: peltate, capitate, stipitate, and patelliform/cupular. Peltate trichomes are the most abundant ones and present the most uniform distribution. Patelliform/cupular trichomes occur at specific regions, such as prophylls, leaflet blade and nodal regions. Martinella obovata is the only species that presents capitate and stipitate trichomes, which are widely distributed along the entire aerial vegetative axis. Ants were found in all species, mainly at nodal regions. The occurrence of the capitate-type trichome is reported for the first time to the genus. KEYWORDS: Bignonieae, Nectaries, Secretory structures, Stipitate trichome. Estrutura e distribuição de tricomas glandulares em três espécies da família Bignoniaceae RESUMOTricomas glandulares desempenham papel importante na caracterização morfológica de Bignoniaceae e, devido à grande diversidade de formas e funções que esses tricomas apresentam, o objetivo desse estudo foi inventariar os tricomas glandulares presentes no eixo vegetativo aéreo de Amphilophium magnoliifolium, Martinella obovata. e Stizophyllum riparium, bem como analisar sua estrutura e registrar a participação de formigas nessas espécies. Amostras frescas da região mediana à apical das lâmina foliolar, pecíolo e nó foram fixadas e processadas de acordo com os métodos usuais para microscopia de luz e eletrônica de varredura. Os tricomas glandulares encontrados nas espécies foram: peltados, capitados, estipitados e pateliformes/cupuliformes. Dentre esses tipos o mais abundante foi o tricoma peltado, apresentando também uma distribuição mais uniforme que os demais. Os tricomas pateliformes/cupuliformes estavam em regiões mais específicas, como profilos, lâmina foliolar e na região nodal. Martinella obovata foi a única espécie que apresentou os tricomas capitados e estipitados, amplamente distribuídos ao longo de todo eixo vegetativo aéreo. Em todas as espécies foram encontradas formigas, principalmente nas regiões nodais. A ocorrência do tricoma capitado é relatada pela primeira vez para o gênero.

Deep in the Jelly: Histochemical and Functional Aspects of Mucilage-Secreting Floral Colleters in the Orchids Elleanthus brasiliensis and E. crinipes

“…Glandular trichomes present specialized cells in the glandular head with the ability to produce, store and secrete various substances (Fahn, 1979). According to the constituents of the secretion, the glandular trichomes receive a functional denomination like the nectaries (production of nectar) and the colleters (mucilage and/or lipid-like substances secretion) (Fróes et al, 2015; Tian et al, 2017). In the Orchidaceae, researchers have previously observed the presence of nectaries (Leitão et al, 2014; Pansarin et al, 2015; Solano-Gómez et al, 2016), osmophores (Pansarin and Amaral, 2009; Millner and Baldwin, 2016; Caballero-Villalobos et al, 2017), idioblasts, and colleters (Leitão and Cortelazzo, 2008; Mayer et al, 2011; Cardoso-Gustavson et al, 2014).…”

Leaf Anatomical Comparison Between Natural Hybrid Nepenthes Ampullaria Jack × Nepenthes Mirabilis (Lour.) Druce With the Parental Species in Kerinci, Jambi

“…Shape of the sessile glands in Nepenthes genera look similar to one of glandular trichomes in members of the Bignoniaceae family. Although both families has no close relationship in the taxa, the glands can also be distinguished based on variations by the head cells shape, attachment position to the epidermal surface, and number of stalk cells (Noguiera et al 2013;Fróes et al 2015). Through this study, specific characters in the glandular trichomes can be potential differentiating character by using morpho-anatomical approach.…”

Foliar Micromorphology and Histo-phytochemistry of Cucumber Trees (Kigelia africana (Lam.) Benth)

“…However, the trichome structure, size, position, and abundance vary among species in this family. Fróes et al (2015) stated that glandular trichomes are the characteristic features of the family Bignoniaceae. Only one type of glandular trichome, namely, peltate, was observed on the surfaces of young and mature leaflets of K. africana.…”

“…The presence of trichomes in the family Bignoniaceae has been well documented, and 21 genera in this family have trichomes. However, a thorough investigation of this family has yet to be conducted (Nogueira et al, 2013;Fróes et al, 2015).…”