Morfoanatomia dos órgãos vegetativos de Chrysolaena simplex (Less) Dematt. E Lessingianthus buddleiifolius (Mart. ex DC.) H. Rob. (Asteraceae) em ambientes rupestres da Serra Dourada, Goiás

Abstract

Asteraceae is one of the most common families of cerrado herbs and subshrubs. Plants in this family vary widely in structure in response to environmental conditions. The present study aimed to characterize the morphoanatomy and histochemistry of aerial and underground organs of Chrysolaena simplex (Less.) Dematt and Lessingianthus buddleiifolius (Mart. ex DC.) H. Rob., assess the occurrence of certain classes of secondary metabolites through phytochemical analyses, and study the effects of seasonality on morpho-anatomical and physiological traits. The study was carried out in an area of campo rupestre in the Reserva Biológica Prof. José Ângelo Rizzo of Universidade Federal de Goiás, inside Parque Estadual da Serra Dourada (PESD). Adult individuals of C. simplex and L. buddleiifolius were collected in the dry and rainy seasons. Samples were analyzed using standard techniques of plant anatomy and scanning electron microscopy. Fresh material was used for histochemical tests. The phytochemical analysis used standard reactions to detect classes of secondary metabolites. C. simplex e L. buddleiifolius had similar anatomical traits, such as amphistomatic leaves, monostratified epidermis, thin cuticle, glandular and non-glandular trichomes, anisocytic stomata, dorsiventral mesophyll, collateral vascular bundles and hydathodes. Histochemical tests identified the presence of lipophilic substances and phenolic compounds in the studied species. Phytochemical screening of leaf and stem samples detected the presence of steroids, triterpenoids, flavonoids, and coumarins in both species. In contrast, saponins were only found in L. buddleiifolius. Seasonality affected the morpho-anatomy of the species studied, revealing their great phenotypic plasticity. The underground system of C. simplex was a rhizophore, while the system of L. buddleiifolius was a xylopodium. Secretory ducts were found in the adventitious roots of C. simplex, whereas the roots of L. buddleiifolius had secretory endodermis. Both species had lipophilic substances and inulin crystals. Crystals were observed in the entire rhizophore of C. simplex, but exclusively in the roots of L. buddleiifolius. The phytochemical analysis of the underground systems revealed the presence of flavonoids, saponins and coumarins, but steroids and triterpenoids were only detected in C. simplex.