Caracterização anatômica e histoquímica das glândulas de perfume em flores de Bellucia grossularioides (l.) Triana (melastomataceae)

Abstract

The floral scents consist of a diverse mixture of low molecular weight volatile compounds, mostly lipophilic compounds, which evaporate at room temperature and play an essential role in attracting pollinators. Although the presence of odor is recorded in hundreds of Melastomataceae species, the location and structure of the scent-producing glands (i.e., osmophores) are unknown in the family. The present study aimed to indicate the place of production and anatomically describe the osmophores in Bellucia grossularioides, a melittophilous species of Melastomataceae. For this, anatomical and histochemical analyzes were performed in flowers at anthesis, which emit an intense perfume. Osmophores were found on the adaxial surface of the petals, diffusely distributed. Such surface is marked by pronounced recesses, which may increase the emission area of perfume. These osmophores are made up of papillary epidermal cells with a conical shape and thin cuticle, where oil droplets were recorded, attesting the production of essential oils in this tissue. Furthermore, epidermal cells and subepidermal layers presented phenolic compounds which do not compose the floral bouquet but may have a photoprotective role. This is the first study that proves the site of floral perfume production and presents a structural and histochemical characterization of osmophores in Melastomataceae, clarifying details of this gland which is essential in plant-pollinator interaction and in the reproductive success of zoophilic species.