Estudos taxonômicos e filogenéticos de Solanum sect. Gonatotrichum Bitter (Solanoideae, Solanaceae) no Brasil

• Ano de defesa: 2010
• Autor(a) principal: Leandro Lacerda Giacomin
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Biologia Vegetal; Botânica
• Link de acesso: http://hdl.handle.net/1843/JRSN-8EUM43

Solanum is one of the largest genera among seed plants, with diversity spots in the New World. One consequence of being such a giant genus, is the complex infrageneric subdivision that has been clarified with the improvement of phylogenetics hypothesis, based specially on molecular data. The subdivisions tradicionally accepted have been modified, and some tropical species have an unclear position within the genus. Solanum sect. Gonatotrichum Bitter encomprises a few species, and has been described based on the habit, few flowered inflorescences and the stems vestiture, composed by unbranched hairs. Its position has been remarkably modified in the late studies, grouped within the Brevantherum clade (sensu Weese & Bohs), that comprises mainly woody shrubs or trees, with stellate hairs. A revision of some brazilian herbaria showed that a five species so long treated as incertae sedis might belong to Sect. Gonatotrichum, three of them unknown to science. So, the main goal of this work was to test the monophyly and the circumscription of sect. Gonatotrichum applying a phylogenetic analysis using nuclear and cloroplast molecular data (ITS e trnL-F), and to review the brazilian species that might belong to the section. The results showed that the Brevantherum clade comprises three main lineages. Sect. Gonatotrichum as treated in its original description seems to be monophyletic, and few species from southeastern Brazil with similar morphology compose a distinct subclade within Brevantherum, treated as Solanum bradei species group. The pollen morphology of eight species from the Brevantherum clade, was not useful to separate the three lineages, therefore it does not corroborate the phylogeny results. The unbranched hairs seem to be the ancestral condition within Brevantherum, ocurring in sect. Gonatotrichum and S. bradei species group. A revision of the brazilian species belonging to sect. Gonatotrichum and S. bradei species group is presented, with descriptions, distribution patterns and identification keys. Sect. Gonatotrichum occurs from the southern Brazil thru the south of the United States. A new species of it from Bahia, Brazil, is described. The S. bradei species group is assigned to mountain ranges of southeastern Brazil, being collected from 900 to 2000 meters above sea level. Three new species belonging to the group are described.