Secretory structures in leaf and stem of Esenbeckia febrifuga (A.St.-Hil.) A. Juss. ex Mart. and Esenbeckia grandiflora Mart. (Rutaceae)

ABSTRACT

The secretory structures of Rutaceae are of great importance due to the economic interest in the drug precursors usually stored and/or produced by them. There is considering this, the characterization of stem and leaf secretory structure of Esenbeckia febrifuga and Esenbeckia grandiflora was carried out, emphasizing the ontogenesis of the cavities and the peltate trichome (in E. febrifuga). Oil-secreting cavities, glandular trichomes and idioblasts with oil, alkaloids, and calcium oxalate crystalswere observed. These elements are distributed randomly in the analyzed organs, being more abundant in the younger ones. Glandular trichomes with a secreting head and tetramerous symmetry were observed for the first time in species of Rutaceae. The cavities have a subepidermal origin and eschizolysigenic development, as seen in other species of the same subtribe. Through the ultrastructural analyses of the cavities, were registered the eccrine, the granuloccrine, and the holoccrine processes of secretion, which are common in secretory structures. This set of characteristics is valuable for future taxonomic studies with the group.

Keywords:
glandular trichomes; idioblasts; medicinal plants; ontogenesis; secretory cavities