Morphoanatomy and Histochemistry of three species of Paullinia L. (Sapindaceae)

Abstract

Paullinia is a monophyletic genus of lianas with a neotropical distribution, encompassing approximately 220 species. In Brazil, there are 102 species occurring mainly in the phytogeographic domains of the Atlantic Forest and Amazonia. The species of this genus have diverse uses as psychotropics, bactericides, antioxidants, fish poisons, stimulants and for ritualistic purposes. The genus is nevertheless insufficiently studied from the anatomical and histochemical standpoints. In the present study, morphoanatomical and histochemical investigations were made of the leaves of Paullinia dasygonia Radlk., P. micrantha Cambess. and P. trigonia Vell. The species studied have very similar leaf characters which makes their identification difficult. The leaves have dorsiventral structure, collateral vascular bundles and both non glandular and glandular trichomes which vary in the species as regards shape, length and distribution. The glandular trichomes have neutral polysaccharides and phenolic compounds. In addition, laticifers were observed containing lipid droplets, alkaloids, proteins and phenolic compounds in diverse regions of the leaf. Saponins, which are characteristic of the family, were observed in the secretory trichomes and generally in the mesophyll and midrib. The results obtained provide evidence justifying further pharmacological investigation of these three species, as well as others in the genus.