Anatomical and histochemical studies of vegetative organs of Stylosanthes capitata Vogel

Abstract

The Fabaceae family is widely distributed throughout the world. Among the genera of this family, Stylosanthes Sw., in addition to counting some species used as fodder, also presents species used in traditional medicine. Stylosanthes capitata Vogel, known as arcançú or estilosantes, stands out from the other species of the genus for having a high content in leaf protein and used in traditional medicine. The general objective of this work is to carry out the anatomical characterization of the root, stem and leaves and histochemical study of the leaves of S. capitata. Usual methods in plant anatomy were used for the preparation of analyses in optical microscopy of semi-permanent slides containing cross sections of vegetative organs, and paraderms of the leaflet blade of S. capitata. Histochemical tests were also carried out in order to locate the metabolites in cross sections of leaflet blades. The microscopic evaluation allowed the identification of characteristics in the root, such as the presence of sclerenchyma; stem with bicollateral vascular bundle, presence of prismatic crystals; on the petiole with 1–3 layers of palisade parenchyma and bicollateral vascular bundle; and leaf blade with paracytic and anisocytic stomata on the abaxial surface, differentiation in the layers of palisade parenchyma and spongy parenchyma, and absence of secretory appendages in all structures analyzed. Through histochemical techniques, the presence of phenolic compounds, lipophilic compounds, lignin, and proteins was evidenced. The results are fundamental for the pharmacobotanical standardization of the studied specie.