Traços morfoanatômicos foliares e a influência sobre a herbivoria e a coexistência de duas espécies de Microgramma (Polypodiaceae) em um fragmento florestal amazônico.

Abstract

About 29% of fern species are epiphytes, representing a diverse and important group in the canopy of tropical forests. Epiphytic ferns normally show characteristics of tolerance to water stress, resisting desiccation. However, this set of tolerance characteristics is little contemplated by studies that aim to verify morphoanatomical information. Therefore, this study aimed to determine objectives and compare morphoanatomical characteristics of Microgramma lycopodioides (L.) Copel. and M. reptans (Cav.) A.R.Sm., interpreting the ecological aspects of the convergence or divergence of characteristics against the epiphytic habitat, as well as their effects on herbivory. The study took place in the Utinga State Park, an urban forest fragment, located within the Belém Endemism Center. The species were sampled in phorophytes close to the forest edge. About 60 leaves were collected and fixed using usual protocols for anatomical analyzes in light and electron microscopy, as well as histochemistry. In addition, 90 leaves were collected to measure herbivory damage, classifying leaves into the following protected categories: intact leaves, 0.01-1%, 1-5%, 5-25%, 25-50%, 50- 75% and 75-100% of leaf area removed. Histochemical tests performed on the secretory structures of the tested species were positive for phenolic compounds, total lipids, acidic mucilages, alkaloids, proteins and total polysaccharides. These results demonstrated that several characteristic and histochemical characteristics are related to the adaptation of these epiphytes in extreme environments with high luminosity and water deficit, such as forest edges, thus regulating water loss. Despite being species belonging to the same genus, it was noted that individuals of M. reptans may have better adapted to the environment and herbivores, developing different characteristics. However, it is necessary to investigate the knowledge of the morphofunctional attributes, especially in the diagnosis of secretory structures and their evolution in different groups of ferns.