RESUMO
ABSTRACT Ageratum conyzoides L., belonging to the family Asteraceae, is a tropical plant found in some regions of Africa, Asia and South America. This species is popularly known as billy goat weed, “mentrasto” and “catinga-de-bode” and has a large variety of secondary metabolites and biological activities mentioned in the literature. The objective of this work was to contribute the pharmacobotanical standardization of A. conyzoides. Cross-sections were obtained, by hand, for microscopic characterization of root, stem, petiole and leaf blade; to the leaf blade were still made paradermal and longitudinal sections, scanning electron microscopy analysis and maceration. The analysis showed that secretory structures ducts are evidenced only in the petiole and the leaf blade. The root has parenchymatous medullar region; stem, petiole and leaf blade exhibit striated cuticle. Non-glandular trichomes are present in stem, petiole and leaf blade, while capitate glandular trichomes are present only in the leaf blade and are restricted to the abaxial face. These anatomical features are useful for diagnosis of the species and provide support to their quality control.
RESUMO
Ageratum conyzoides L. (Asteraceae) é uma espécie herbácea que ocorre em áreas de cerrado e, por se tratar de planta medicinal, é cultivada em escala familiar. O objetivo deste trabalho foi estudar possíveis alterações no desenvolvimento das plantas quando cultivadas em solos com texturas diferentes (solo de cerrado, franco arenoso ou solo de terra roxa, muito argiloso). Foram analisados aos 40, 70 e 90 dias, o comprimento do caule e da raiz, massa seca da parte aérea (caule e folhas) e das raízes, número de folhas e área foliar; além de parâmetros anatômicos foliares, como a densidade de tricomas. Os resultados mostraram que os comprimentos do caule e da raiz aumentaram no decorrer do experimento, independentemente do substrato (com exceção do comprimento da raiz de plantas cultivadas em solo de terra roxa). Porém, o comprimento do caule foi sempre maior nas plantas cultivadas em solo de cerrado, enquanto o comprimento da raiz foi significativamente maior somente aos 90 dias de cultivo neste solo. As biomassas secas da raiz e do caule também foram maiores nas plantas cultivadas em solo de cerrado por 70 e 90 dias, respectivamente. A massa seca foliar foi maior nas plantas cultivadas em solo de cerrado a partir dos 70 dias de experimento. Esse aumento foi devido ao maior número de folhas produzidas e a maior área foliar dessas plantas. No geral, a anatomia foliar não diferiu, porém o número de tricomas glandulares foi maior nas plantas cultivadas em solo de cerrado. Os resultados indicaram que esta espécie tem melhor desenvolvimento quando cultivada em solo mais arenoso.
Ageratum conyzoides L. (Asteraceae) is a herbaceous species found in cerrado areas and grown in family scale since it is a medicinal plant. The aim of this work was to study possible alterations in the plant development when grown in soils presenting different textures (a sandy-loam cerrado soil, or a very clayish red earth soil). At 40, 70 and 90 days, stem and root length, shoot (stem and leaves) and root dry matter, number of leaves and leaf area were evaluated, in addition to leaf anatomical parameters, such as trichome density. Stem and root length increased over the experiment under any substrate (except root length of plants grown on red earth soil). However, stem length was always higher in plants grown on cerrado soil, whereas root length was significantly higher only at 90 days of cultivation on this same soil. Root and stem dry biomass were also higher in plants grown on cerrado soil at 70 and 90 days, respectively. Leaf dry matter was higher in plants grown on cerrado soil from 70 days of experiment. This increase was due to the larger number of produced leaves and the higher leaf area of those plants. In general, leaf anatomy does not differ; however, the number of glandular trichomes was larger in plants grown on cerrado soil. Such results indicated that this species had a better development when grown on sandier soils.