Anatomia dos órgãos vegetativos de espécies neotropicais de Gentianaceae Jussieu: contribuições à taxonomia e filogenia

• Autor(a) principal: Dalvi, Valdnéa Casagrande
• Data de Publicação: 2010
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2569
• topic: Gentiaceae - Secreção; Células vegetais - Secreção; Gentianaceae - Anatomia; Curtia; Calolisianthus; Hockinia; Deianira; Gentiaceae - Secretion; Plant cells - Secretion; Gentianaceae - Anatomy; Curtia; Calolisianthus; Hockinia; Deianira; CNPQ::CIENCIAS BIOLOGICAS::BOTANICA

The Gentianaceae family has around 1615-1688 species and 87 genera which are organized in 6 tribes (Chironieae. Exaecae. Gentianeae, Helieae, Potalieae and Saccifolieace, besides lhe genus Voyria which does not have a fixed position yet. This classification has now been accepted by the scientific community once it considers phylogenetic affinities based on molecular data which demonstrate congruence with the extenal morphology, palynology and chemical taxonomy. This family shows a great anatomical and morphological variety. Nevertheless, only molecular synapomorphies, or the union of these with other characters, consolidate the family and the six tribes as monophyletic groups. Regarding the position of the species and genera, circumscriptions have not been well established. This study aims to describe the anatomy of the vegetative organs of Gentianaceae species belonging to Calolisianthus (Helieae), Curtia and Hockinia (Saccifolieae); and Deianira (Chironieae); to contribute to the knowledge of the family, and to select anatomical characters which may be useful to taxonomy and phylogeny of this group. Specimens of Calolisianthus pedunculatus, Deianira damazioi, Curtia tenella, Curtia tenuifolia, Curtia patula and Curtia diffusa were collected at different Rupestrian Fields (Rocky Outcrops) in the State of Minas Gerais, Brazil. Samples of Curtia obtusifolia, Curtia conferta, Curtia verticillaris and Hockinia montana from voucher material were also analyzed. as well as specimens of Declieuxia fruticosa and Declieuxia cordigera, which were the Rubiaceae species used as the external group in the cladistic analysis. Samples of leaves, stems, and roots were processed according to the usual vegetal anatomy methodology for dissociating the epidermis, diaphanization, methacrylatc and paraffin embedding, histochemical tests, and scanning electron microscopy. For the cladistic analysis, data from literature of seven species belonging to the tribes studied were included. Altogether, 59 anatomical charaters were analysed. The Maximum Parsiimony Analysis was run by the Paup 4.0.b10 version program. All the species structurally analysed showed anomocytic stomata placed at the same level of the other epidermal cells, stems with stomata and internal phloem, nectarioles, and colecters. The characters considered as diagnostic for the different species are as follows: type of vascular bundle; distribution and type of stomata; presence of hypodermis; presence of cuticular flanges; outlining of the epidermal cells; presence of crystals; patterns of venation; shape of the stem; number of wings in thc stem; prcsence of aerenchyma, mycorrhiza and Casparian strips evident in the roots: type of root growth; and variation on the type and distribution of the colecters and nectarioles. ln the cladistic analysis, Gentianaceae, showed to be monophylectic, a position supported by a bootstrap of 100%. Three monophyletic clades giving support to the Calolisianthus (67% of bootstrap"), Curtia (89% of bootstrap") and Hockinia genus (86% of "bootstrap") also emerged. On the other hand, Deianira showcd polytomies probably due t0 insufficient anatomical data about the species belonging to this genus, especially. the ones regarding the secretory structures. Data on the secretory structures, pattern of venation, and type of stomata showed to be promising to the phylogeny of this group. It should also be highlighted the importance of using anatomical characters to solve taxonomic problems regarding the different species of Gentianaceae. Thc necessity of data from different sources of characters in order to achieve a more accurate analysis of the phylogenetic relationships among the different taxonomic categories of Gentianaceae should also be emphasized.