How do legumes cope with environmental filters in savanna ecosystems? Analysis of morphoanatomical and ultrastructural traits of legumes aerial organs and ecological implications

Abstract Savannas are fire-prone seasonal ecosystems determined by environmental filters such as fire, herbivory and water availability, which change the dynamics in these environments. Plants growing in such conditions have adaptive traits that enable them to survive under different disturbances and stresses, not only on the underground organs, but also on aerial organs. Therefore, this work aimed to describe morphoanatomical and structural traits of the stem and leaves of eight representative legume species from Cerrado, related to ecological functions associated with resistance against environmental filters present in savanna ecosystems. We performed morphoanatomical and structural analysis of aboveground organs using four techniques: (1) Samples included in historesin were sectioned on a rotary microtome; (2) Fresh samples were sectioned on a sliding microtome; (3) Fresh samples were free-hand sectioned (4) The ultrastructural analysis of the leaf samples was performed on Scanning Electron Microscope. According to morphoanatomical analyses, it was possible to identify two functional groups, such as plants with xeromorphic traits and plants with mesomorphic traits. The traits protect plants from flame temperatures, sun exposure, drought, herbivory, and other environmental filters. Resprouting species of this study also have several important morphological and anatomical traits that enable these species to resist drought, fire, herbivory and other filters. The integration of morphoanatomy to functional ecology may be a remarkable tool in understanding vegetation responses to disturbances and stresses.