Aspectos reprodutivos de plantas do ecossistema vereda

Abstract

Plant species have a variety of reproductive aspects that are fundamental to their evolutionary process and the ability to live in diverse environments. Among these aspects, the occurrence and distribution of sexual and reproductive systems, reproductive strategies and interactions with the pollinator depend on the life history of the plant, including its habitat and habit and even the degree of conservation of the area. In this way, we seek to identify the occurrence and abundance of sexual and reproductive systems, characterizing the reproductive aspects of plants in the vereda ecosystem, considering the floristic composition and particularities of the environment. The study area was a vereda located in the Pandeiros River Environmental Protection Area (APA Pandeiros), in the municipality of Bonito de Minas, in northern Minas Gerais State, Brazil. The species were selected according to a phytosociological study carried out in the area in 2017, using the plot method, allocated in transects along the path. To determine the sexual and reproductive systems, flower collections and pollination treatments were carried out between march 2018 and december 2019. To characterize the sexual systems, the species were classified as hermaphrodite, dioica and monoica. The reproductive systems evaluated were apomixis, allogamy and autogamy. To determine the reproductive systems of seven species, open pollination, spontaneous self-pollination and apomixis treatments were performed. For the other species, the classification of the reproductive system was made based on the literature, with the determination of the sexual system and with the presence of barriers to self-pollination. Of the 57 species recorded in the study area, it was possible to evaluate the reproductive aspects of 45 species, about 80% of the identified flora. The predominant sexual system was hermaphrodite with 71%, followed by dioicia with 29%. The predominant reproductive system was the alogamus, registered in 30 species, followed by autogamy in only five species and apomixis in three species of the genus Miconia. The Principal Component Analysis (PCA) confirmed the relationship between the distribution of the sexual and reproductive systems of the plants studied with the different habitats and habits, with the predominance of dioicia and allogamy among tree species and in the forest and hermaphroditism environment, autogamy and apomixis among shrub species and in the open area. The occurrence and distribution of sexual and reproductive systems in the vereda ecosystem corroborates with other studies carried out in tropical forests and plant formations in some of the Brazilian biomes. Our results demonstrate that although most species are hermaphroditic, they present strategies and mechanisms that favor allogamy as a reproductive system and are therefore dependent on pollinators.