Anatomia foliar como subsídio para a sistemática de Croton L. (seções Cleodora e Lamprocroton), Euphorbiaceae

• Ano de defesa: 2013
• Autor(a) principal: Vitarelli, Narah Costa
• Orientador(a): Meira, Renata Maria Strozi Alves
• Banca de defesa: Azevedo, Aristéa Alves , Caruzo, Maria Beatriz Rossi , Riina, Ricarda
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Doutorado em Botânica
• Departamento: Botânica estrutural; Ecologia e Sistemática
• País: BR
• Palavras-chave em Português: Folhas - Anatomia; Secreção; Filogenia; lamprocroton; Cleodora
• Palavras-chave em Inglês: Leaves - Anatomy; Cecretion; Phylogeny; Lamprocroton; Cleodora
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::BOTANICA
• Link de acesso: http://locus.ufv.br/handle/123456789/373

Croton L. (Euphorbiaceae) is one of the largest genera of flowering plants, has a elevated species number, a great morphological diversity and broad distribution (predominantly tropical). Croton has a great variety of chemical compounds. Its large size, great morphological diversity, broad distribution and the lack of morphological synapomorphies made difficult its taxonomy and systematics. The genus was divided into 40 sections defined by a suit morphological characters, however molecular phylogenetic analyzes have shown that many of these sections are not monophyletic. The sections Cleodora (subsections Sphaerogyni and Spruceani) and Lamprocroton (subsetions Argentini and Lamprocroton) were reviewed considering morphological and molecular data. Based on this work, we studied leaf anatomy of species of section Cleodora, section Lamprocroton subsection Lamprocroton and related out group. A data matrix was built with the diagnostic anatomical characters. This matrix was combined with the molecular data matrix and, in some cases, with the morphological data in phylogenetic analisis using Maximum Parsimony (MP) and Bayesian Inference (BI). We performed a Ancestral Character State Reconstruction using the anatomical characters. The results of this study show that the use of anatomical characters in phylogenetic analysis contributes to the clarification of the relationships between species of Croton and allow us to understand mechanisms of evolution of vegetative structures. Leaf trichomes of some Croton species correspond to a complex multicellular structure, adapted to the foliar water uptake. Besides the ecological importance of the species studied leaf structures can support the phylogenetic interpretations. The leaf anatomical characters, especially the secretory structures, contribute to the clarification of the evolutionary history of Croton and clarify interrelationships among their species. The anatomical characters were relevant in resolving the topology of internal branches in section Cleodora and increasing node support, contributing to the clarification of the relationships between species in this section. The species of subsection Lamprocroton (sect. Lamprocroton) show very similar structural and molecular (on the markers used, ITS and trnL-trnF) showing unclear relationships between species in both molecular phylogeny analisis and combining molecular and anatomical data analisis. Although the anatomical characters have not been sufficient to resolve the polytomy in subsection Lamprocroton, they were important to clarifying relationships among species. The results of this study reveal a new position within the section Lamprocroton with the exclusion of C. pygmaeus from subsect. Lamprocroton and its new recircunscription in subsect. Argentini. Croton imbricatus should be remove from sect. Lamprocroton to another section within Croton. We suggest possibilities for C. imbricatus new position in Croton.