Aspectos anatômicos de Ocimum americanum L., uma espécie medicinal e aromática da Amazônia

Abstract

Ocimum americanum L., vernacularly known as "white basil", is an Amazonian aromatic and medicinal species found in urban areas in the fairs of Belém, commercialized in the Ver-o-Peso market at popular herb stalls. About this species there are reports about its medicinal and therapeutic properties, proven antimicrobial action, extraction and analysis of essential oils and repellent action, however, there is no information regarding the leaf anatomy. With the objective of contributing to the biological knowledge of the species, an anatomical analysis of the structure and ultrastructure of the leaves was carried out. The relevance of the anatomical study is directly related to the presence of complex secretory structures, which are carriers of chemical substances of economic value, located in the innermost part of the gland, protected by a cuticular layer that contains and prevents the drying of the secretion. In the methodology, we used tn natura material, fixation in FAA70%, the techniques of dissociation, diaphanization, histological sections, application of histochemical tests and electronic analysis in scanning microscopy SEM. In this analysis, emphasis was given to the secretory structures, classifying the glandular and non-glandular trichomes, in which three types of trichomes are observed: two glandular and one simple tector. The glandular are capitate and peltate, the peltate are complex mutiticellular with two radial circles overlapped by more than 10 cells, which in cross section is located in an invagination, in these several cells compose laterally the external wall. Anatomical analysis of the structure and ultrastructure of Ocimum americanum shows a leaf surface with thick epicuticular wax, diacritical stomata and complex secretory structures considered common to species of the genus Ocimum L.