Morfoanatomia dos órgãos vegetativos aéreos e subterrâneos de espécies de Lamiales em área relictual de Cerrado, Paraná, Brasil

Abstract

The dissertation is structured in two chapters. The first chapter aimed to characterize the morphology and anatomy of the aerial organs of six species of Lamiales that regrew after controlled burning in a grassland area of the Guartelá State Park, in order to understand their adaptive responses to local pressures. The second chapter analyzed the underground systems of Hyptis campestris and Salvia aliciae (Lamiaceae) and Lippia campestris and Lippia lupulina (Verbenaceae), with a focus on persistence strategies in the face of prolonged drought and recurrent fire in a grassland area. In the first chapter, different degrees of morphoanatomical specialization were observed between the species. Salvia aliciae, Lippia campestris and L. lupulina have markedly xeromorphic attributes, such as leathery leaves, thick cuticle, developed palisade parenchyma and thickened epidermal walls, indicating greater drought tolerance. Meanwhile, Dyschoriste hygrophiloides, Hyptis campestris and Ruellia dissitifolia exhibit mesomorphic characteristics, such as; chartaceous leaves, larger leaf area, thin cuticle and hypo- stomatal surface, suggesting less specialization to water deficit conditions. All the species analyzed have perennial underground organs and showed regrowth approximately one month after burning (September), with regrowth recorded in (October) at the start of the rainy season, indicating a rapid phenological response. The rapid phenological response observed may be associated with underground systems, which ensure post-fire regrowth and survival in drought, and are an essential mechanism for the persistence of species in the face of local disturbances (drought and fire). In the second chapter, it was observed that all the species have xylopodia and adventitious roots of different sizes, which is a fundamental strategy not only for absorption, but also for storing water and nutrients during periods of water restriction. In addition, the presence of growth layers in the xylopodium of the species indicates a seasonal pattern of cambial activity, directly related to the variation in the availability of resources throughout the year. The presence of reserves, such as starch, and phenolic compounds, associated with chemical defense, is a relevant functional strategy for the survival of the species. The persistence capacity of the Lamiaceae and Verbenaceae species evaluated in the Cerrado relictual area is strongly related to the presence of xylopodia, which play a fundamental role in maintaining the species, especially in the face of water stress.