Leaf anatomy of Cordiera sessilis (Vell.) Kuntze (Rubiaceae)

摘要

A study on the leaf anatomy of Cordiera sessilis (Rubiaceae), a native medicinal shrub from Brazilian Cerrado was carried out to contribute for species identification and provide support for future biochemical studies and medicinal application. Leaves were collected, fixed and processed by usual techniques, and studied by light and electron microscopy. Quantitative analyzes of stomata and trichomes were performed. The leaves showed typical characteristics of Rubiaceae family, like hypostomatic leaves, paracytic stomata, dorsiventral mesophyll and collateral bundles. Two types of vascular patterns were identified in the petiole: in distal part, the vascular system is arranged cylindrically surrounded by sclerenchyma sheath and in proximal part, the vascular system is arranged in U-shape coupled to sclerified cells. The micromorphological organization of leaf surface, epicuticular wax types, the petiole pattern and histochemical characteristics as the presence of druses, sand crystals and alkaloids and absence of raphids in the mesophyll, midrib and petiole are considerate representative characteristics of C. sessilis and may be useful in the species identification.