Diversity of Floral Glands and Their Secretions in Pollinator Attraction

Floral development of the myrmecophytic Acacia cornigera (Leguminosae)

“…Floral fragrances are considered the attractants and repellents per excellence (Junker & Blüthgen 2010, Tölke et al 2019, although the latter function is more expected among plants that form mutualistic interactions with ants and have been characterized as the chemical compounds that facilitate access to pollinators (Willmer & Stone 1997). Petals are considered the main fragrance-emitting organs, and the structures involved are the epidermis (osmophores), trichomes and stomata (Marinho et al 2014, Huchelmann et al 2017, Tölke et al 2019.…”

“…Floral fragrances are considered the attractants and repellents per excellence (Junker & Blüthgen 2010, Tölke et al 2019, although the latter function is more expected among plants that form mutualistic interactions with ants and have been characterized as the chemical compounds that facilitate access to pollinators (Willmer & Stone 1997). Petals are considered the main fragrance-emitting organs, and the structures involved are the epidermis (osmophores), trichomes and stomata (Marinho et al 2014, Huchelmann et al 2017, Tölke et al 2019. In A. cornigera, the presence of stomata on mature bracts and petals could be indicative of their participation in the emission of volatile compounds either for attracting pollinators like in A. berlandieri (Gómez-Acevedo et al 2007) or even to repel resident ants, which is consistent with ecological studies that reveal that ants do not approach mature inflorescences, even though they do patrol them at immature stages (Willmer & Stone 1997, Ghazoul 2001, but this fact needs to be studied in greater detail with anatomical and histochemical studies in both petals and bracts.…”

Anatomy of the floral nectaries of selected species of Gardenieae (Rubiaceae)

“…It is common the presence of floral nectaries in plants that are pollinated by insects or birds (Fahn 1982), in which these secretory structures are involved in the pollination process. The floral nectaries can be found in almost all parts of flower (sepal, petal, stamen, receptacle, ovary, and style) and they can produce a wide chemically variety of sweetened exudates (Fahn 1982;Bernardello 2007;Tölke et al 2019). In addition, the morphology and location of nectaries can be useful for establishing relationships between taxa in systematic treatments (Fahn 1982;Bernardello 2007;Nepi 2007;Almeida et al 2013;Tölke et al 2018;Phukela et al 2020).…”