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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Esporos de espécies selecionadas de musgos (Bryophyta) de Minas Gerais: morfologia, ultraestrutura e aspectos ecológicos

Rodrigues, Raquel Saar 21 February 2014 (has links)
Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-07-04T10:44:48Z No. of bitstreams: 1 raquelsaarrodrigues.pdf: 1388727 bytes, checksum: 2d848a6f30cf75ad6633c4cecf0c916f (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-08T13:09:32Z (GMT) No. of bitstreams: 1 raquelsaarrodrigues.pdf: 1388727 bytes, checksum: 2d848a6f30cf75ad6633c4cecf0c916f (MD5) / Made available in DSpace on 2017-08-08T13:09:32Z (GMT). No. of bitstreams: 1 raquelsaarrodrigues.pdf: 1388727 bytes, checksum: 2d848a6f30cf75ad6633c4cecf0c916f (MD5) Previous issue date: 2014-02-21 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Os musgos, incluídos na divisão Bryophyta, são caracterizados pela criptogamia, ausência de vasos condutores e presença de gametófitos folhosos (fase de vida dominante), com filídios organizados espiraladamente. O padrão de ramificação do gametófito, em conjunto com a sua forma de crescimento, é chamado de forma de vida que, nos musgos, pode ser tapete, trama, dendróide, pendente, relva e almofada. O esporófito é formado por pé, seta e cápsula, sendo esta última, o local de produção dos esporos, unidades de dispersão das espécies, que apresentam parede celular formada por perina, exina e intina. Estudos em Palinologia de musgos, já elucidaram questões importantes acerca da esporogênese, germinação e morfologia dos esporos de muitas espécies, sendo alguns deles empregados em taxonomia. No entanto, dados que correlacionam características morfológicas dos esporos com as estratégias adaptativas das espécies ainda são raros. Sendo assim, o objetivo do presente trabalho foi realizar o estudo palinológico de 19 espécies selecionadas de musgos que ocorrem no estado de Minas Gerais, e relacionar os dados palinológicos obtidos, com as estratégias adaptativas das espécies estudadas. Foram incluídas no conjunto amostral espécies acrocárpicas e pleurocárpicas, que ocorrem em diferentes substratos, e com formas de vida variadas. Para o estudo palinológico das espécies, os esporos foram observados sob microscópio de luz antes e após acetólise, momento em que foram realizadas as medidas padrão para estudos palinológicos, e microscópio eletrônico de varredura. Após as análises palinológicas e obtenção dos dados acerca das características adaptativas das espécies, as informações foram incluídas em uma matriz binária e, empregando-se o software PAST 15.2, foi realizada a análise de agrupamento (cluster) para verificar como as espécies se agrupam em função das características estudadas. Os resultados palinológicos demonstram a existência de três padrões distintos de ornamentação da perina: granulada formada por grânulos simples, granulada formada por grânulos compostos e baculada. A ornamentação observada nos esporos de Weissia controversa foi descrita pela primeira vez. A espécie Leptodontium viticulosoides apresentou esporos anisomórficos. As análises de agrupamento revelam uma relação entre espécies acrocárpicas, a ocupação do substrato cimento e a presença de uma parede espessa no esporoderma. / Mosses are cryptogamic land plants, included in Bryophyta and characterized by an avascular condition and the presence of leafy gametophytes (dominant life generation), with leaves spirally arranged around the stem. The growth form, together with the branching pattern, is called the life-form, which may be mat, weft, dendroid, pendant, turf and cushion. The sporophyte consists of foot, seta and capsule. The spores, dispersal units of mosses, are formed in the capsule and show a three layered sporoderm, consisting in perine, exine and intine. Studies in palynology of mosses have elucidated important issues about sporogenesis, spore germination and morphology of many species, some of them being employed in taxonomy. Observing that the data correlating morphological characteristics of the spores with the adaptive strategies of species are still rare, this work aimed to study the spores of 19 species of mosses which occur in the state of Minas Gerais and to correlate the palynological data obtained with the adaptive life strategies of species. We included in the sample a set of acrocarpous and pleurocarpous mosses which occur on different substrates and show with different life-forms. For the palynological study, the spores were observed untreated or submitted to the acetolysis method, under light microscope and scanning electron microscope. After we obtained the data concerning to the palynological analysis and the adaptative strategies of species, the information was included in a binary matrix and through the PAST 15.2 software, a cluster analysis was performed. The palynological results show three distinct patterns of perine ornamentation: granular formed by individual granules, granular formed by compounded granules and baculated. The ornamentation observed in spores of Weissia controversa was first described. Leptodontium viticulosoides showed anisomorphic spores. Cluster analysis revealed a relationship between acrocarpous species, the occupation of the substrate concrete and the presence of a thick wall in sporoderm.
2

Taxonomic study of the Eurasian taxa of Tortula muralis (Pottiaceae, Musci) complex / Taxonomic study of the Eurasian taxa of Tortula muralis (Pottiaceae, Musci) complex

KOŠNAR, Jiří January 2014 (has links)
The thesis aims at clarifying the taxonomic difficulties in the Tortula muralis complex. For the first time, the group was studied by means of morphometric analysis, ploidy level assessment by flow cytometry, and molecular analysis based on sequencing of ITS region of nuclear ribosomal DNA. Morphometric and cytometric studies found only two well distinguished groups within the complex. These groups corresponded to the markedly variable species T. muralis and to the rather uniform species T. lingulata. Variability in ITS sequences suggested extensive gene flow among some of traditional morphologically defined taxa of the complex. Multiple polytopic autopolyploid origin of polyploids was revealed in some taxa. Changes in taxonomic conception of T. muralis complex were proposed in order to reflect structure of morphological, karyological, and DNA variability in the group. Natural hybridization is probably an important evolutionary mechanism that generated morphological diversity and taxonomic complexity in the mosses of T. muralis complex.

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