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

JUDKEVICH, MARINA DANIELA; SALAS R.M.; GONZALEZ ANA M.

Rodriguésia

Revista do Jardim Botânico do Rio de Janeiro

Año: 2021

Rubiaceae is one of the five most species-rich families of Angiosperm, its flowers arecharacterized by a nectariferous disc surrounding the base of the style; however, there arealmost no studies on anatomy of these structures in the family. The aim of this study was todescribe for the first time the anatomy of the floral nectaries in the tribe Gardenieae(Rubiaceae). Flowers from Cordiera concolor, Genipa americana, Randia calycina, Randiaferox, Randia heteromera, Randia micracantha, and Tocoyena formosa were collected,photographed, and processed using conventional techniques for observation with optical andscanning electron microscopies. In all species the nectary is differentiated histologically intoepidermis, nectary and sub-nectary parenchyma, and vascular bundles. Nectar is exuded vianectarostomata. The nectaries have reproductive function, and are structural and mesenchymalduring the floral stage. Whereas after corolla has fallen they are persistent nectaries, with postfloralsecretion and extranuptial function. In addition, floral visitors that appeared on openflowers and after corolla fall were recorded.Key words: floral structure, nectaries, post-floral secretion, Rubiaceae.