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

Abstract

Cavitated secretory trichomes are characterized by a short or absent stalk that is connected to a secretory hollow head. They are rare structures in angiosperms; in Fabaceae, they have been recorded in only seven genera, including Bauhinia s.s. Because B. curvula and B. rufa exhibit glands that are responsible for attracting pollinators to flowers, this study aimed to test whether the cavitated secretory trichomes present in the flowers of these species have an attraction function. As leaf trichomes are commonly related to plant defence, comparative analyses of the morphology, ontogeny, ultrastructure and chemical profile of the secretory trichomes present in flowers and leaves were conducted. It was found that cavitated secretory trichomes are similar in their external morphology and development, regardless of the organ or species analysed. However, interspecific differences were found in the secretion process and chemical profile of the exudate. The differences found in the cavitated secretory trichomes between species indicate that they secrete distinct compounds, whereas the similarities found in these structures between vegetative and reproductive organs indicate that the cavitated trichomes have equivalent ecological functions within a species, probably in plant defence during organ development. © 2015 The Linnean Society of London, Botanical Journal of the Linnean Society, 2016, 180, 104–122.

Trichomes that secrete substances of a mixed nature in the vegetative and reproductive organs of some species of Moraceae

“…On the other hand, the exclusive presence of polysaccharides in the subcuticular space of the trichomes of D. cayapia pistillate inflorescences indicates that these structures may exert different functions in its reproductive organs, such as in the adhesion of pollen grains. Moreover, it is important to consider that only more specific chemical tests of these trichomes would permit us to state whether their exudate is the same for all organs or differs between them, thus permitting a more objective inference about their functions (see Marinho et al 2016). …”

Beyond pollination: diversity of secretory structures during flower development in different legume lineages

“…2). Interestingly, although their presence is a wide condition in legumes, their distribution and morphology are highly variable and of potential systematic value for some groups such as cavitated trichomes in the genus Bauhinia (Duarte-Almeida et al 2015;Marinho et al 2016) and the trichomes present in species of the Caesalpinia clade (Ragonese 1973;Leelavathi & Ramayya 1983;Lersten & Curtis 1994;1996;Rudall et al 1994;Lewis & Schrire 1995;Simpson & Miao 1997;Pascal et al 2000;Warwick & Lewis 2009;Melo et al 2010) and in the genus Mimosa (Santos-Silva et al 2013). Our reports of floral secretory trichomes are original for 11 of the 15 species studied belonging to the Cassia, Dimorphandra, Mimosoideae and Papilionoideae clades.…”

“…Studies of this nature are concentrated on nectaries (Bernadello 2007) and osmophores (Mansano & Teixeira 2008;Marinho et al 2014), secretory structures related to pollination, while other types such as secretory trichomes, idioblasts, cavities and ducts have been less explored in this family comprising such a wealth of species. The few examples available include studies of secretory trichomes in the floral parts of Bauhinia (Tucker 1984, Marinho et al 2016 and Chamaecrista dentata (Meira et al 2014), in the perianth of Indigofera (Kumar et al 1986, Marquiafável et al 2009, in the sepals of Dahlstedtia , in the ovary of Glycine (Healy et al 2009), and in the bracteoles of Mimosa (Leelavathi et al 1984); studies of the colleters in the bracts of Holocalyx balansae and Zollernia ilicifolia (Mansano & Teixeira 2008) and Hymenaea stignocarpa (Paiva & Machado 2006); of the secretory idioblasts in the perianth of Caesalpinia echinata (Teixeira & Machado 2007) and in the ovary of Swartzia langsdorffii (Colpas & Oliveira 2002); and studies of the secretory cavities in the perianth of Dahlstedtia (Teixeira & Rocha 2009, in the ovary of Hymenaea stigonocarpa (Paiva & Oliveira 2004), and of the secretory ducts and cavities in the petals and sepals of Pterodon pubescens, Dipteryx alata and Taralea oppositifolia (Leite et al 2014).…”

Glandular trichomes of Robinia viscosa Vent. var. hartwigii (Koehne) Ashe (Faboideae, Fabaceae)—morphology, histochemistry and ultrastructure

“…Various morphotypes of glandular trichomes have been distinguished in the Fabaceae family, e.g. in the subfamilies Cercidoideae (Marinho et al 2015), Caesalpinioideae (Coutinho et al 2015Silva et al 2017), and Faboideae (Matos and Paiva 2012;Flores et al 2019;Vargas et al 2019). Representatives of the family Fabaceae often have other exogenous secretory structures, such as floral nectaries (Konarska 2020), extrafloral nectaries (Gonzalez and Marazzi 2018), and osmophores (Marinho et al 2018).…”