Micromorphology and Leaf Anatomy of Rubiaceae Species from Itatiaia National Park, State of Rio de Janeiro, Brazil

ABSTRACT

Aspects of leaf anatomy and micromorphology of Galium hypocarpium, Guettarda viburnoides and Posoqueria latifolia (Rubiaceae) were analyzed through light microscopy and scanning electron microscopy in order to provide support for the family taxonomy and to assist in the understanding of the relationship between the environmental features of the Atlantic Forest. The tested species showed ornamented cuticle and thin film of wax adaxial surface. G. hypocarpium abaxial surface presented striated cuticle, while P. latifolia cuticular ornamentation was present only in the stomata. Trichomes were observed in both surfaces, except for P. latifolia. and G. viburnoides, which presented abaxial surfaces covered with uniseriate trichomes containing prismatic crystals. The studied species are hypostomatic with paracytic stomata and collateral vascular system surrounded by parenchymatic bundle sheath cells; except for G. viburnoides, whose bundle sheath extends to the adaxial epidermis face. Secretory cells with lipid content were observed in the abaxial epidermis of G. hypocarpium. The species showed mostly mesomorphic anatomy, several defense mechanisms such as trichomes, and secretory structures related to the environment of the Atlantic Forest.

Keywords:
Atlantic Forest; morphoanatomy; Rubiaceae.