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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.
21

Hong Kong Cyperaceae: taxonomy, ecology and geography

Shaw, Julia. January 2000 (has links)
published_or_final_version / Ecology and Biodiversity / Master / Master of Philosophy
22

Sedges as bedding in Middle Stone Age Sibudu

Sievers, Christine 30 July 2013 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy 2013 / Cyperaceae (sedge) nutlets dominate the archaeobotanical assemblage of fruits and seeds recovered from the Middle Stone Age deposits at the rock shelter Sibudu, KwaZulu-Natal, South Africa (Sievers 2006). My aim is to investigate the implications of the nutlet presence in terms of human behaviour and to demonstrate that the nutlets were likely brought into the shelter on sedge culms (stems) deliberately harvested by people and informally placed on the shelter floor to provide “bedding”, a surface for working, resting or sleeping. I use various empirical and experimental approaches to confirm the use of sedges for bedding at Sibudu as early as ~77 000 years ago, almost 50 000 years earlier than any previously identified archaeological bedding. The bedding consists of the sedges Cladium mariscus subsp. jamaicense, Scleria natalensis, S. melanomphala, Cyperus sp. and a panicoid grass, identified through Scanning Electron Microscopy To investigate repeated and deliberate burning of bedding at Sibudu, I use experimental micromorphology and I compare the signatures of the Sibudu sediments with burned fresh sedge and grass bedding. I undertake further fire experiments, also in open air situations, to answer questions about burning sedge beds and the taphonomic implications. Experimental sedge bedding fires are hot and brief. The matrix beneath the fires affects the temperatures achieved both on the surface directly under the fire, and at depths of 2 cm and 5 cm below the surface; an ash matrix conducts heat more effectively than a matrix of 1–2 mm sized particles and allows for carbonisation of buried nutlets. The burning of dry and green bedding indicates that once the bedding is burning, the temperatures are sufficient to carbonise sedge nutlets below both dry and moist bedding. The methodological innovations I introduce are the use of experimental micromorphology to address an archaeobotanical question and the use of GIS-based coexistence analysis of southern African archaeobotanical data to make interpretations about past climate. The analysis develops previous palaeovegetation research in the area (Sievers 2006; Wadley et al. 2008) and provides an environmental context for people/plant activities at Sibudu.
23

A contribution to the taxonomy of Bolboschoenus (Cyperaceae), with particular reference to fruit morphology and the African species.

Browning, Jane Beatrice Mary. January 1998 (has links)
Using the Scanning Electron Microscope (SEM), fruit surface and pericarp anatomy were investigated in the African species of Bolboschoenits (Ascherson) Palla [B. maritimus (L.) Palla; B. glaucus (Lam.) S.G. Smith; B. nobilis (Ridley) Goetghebeur & D.A. Simpson; B. grandispicus (Steud.) K. Lewejohann & W. Lobin] and extended worldwide to cover most known species. There was consideration of type specimens wherever possible. Two main patterns of pericarp construction were revealed, with modifications. Using fruit samples from field populations, a surveillance of embryos was carried out to gain some information on percentages of perfect embryo development and variability in embryo outline (as seen in optical, median sagittal section), within and between selected species. Inflorescence structure within African species was studied and illustrated photographically and diagrammatically. The collective information obtained was directed towards better understanding of species limits within the genus and towards gaining evidence of the significance of natural hybridisation as a cause of morphological variability within some taxa. Formal taxonomy including a key to the identification of the African species is provided. Profuse illustrations of pericarp structure of world species are given, as are colour photographs of the African species, excepting B. grandispicus. A tentative pattern for subgeneric division of Bolboschoenus based primarily on pericarp morphology, is suggested supplemented by a world map illustrating the presently known distribution of the suggested groupings. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1998.
24

Estudo taxonômico de Cyperus subg. Pycreus (P.Beauv.) A. Gray (Cyperaceae) para o Brasil

Silva, Luciana Pereira da January 2017 (has links)
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Biológicas, Programa de Pós-Graduação em Biologia de Fungos, Algas e Plantas, Florianópolis, 2017 / Made available in DSpace on 2017-09-19T04:11:58Z (GMT). No. of bitstreams: 1 347953.pdf: 6614028 bytes, checksum: dbe6fad108589175837f6a746eebca78 (MD5) Previous issue date: 2017 / Cyperaceae é uma grande família cosmopolita de monocotiledôneas. No Brasil é a terceira família mais representativa do domínio fitogeográfico Pampa, sendo também representativa no Pantanal, Caatinga e Floresta Amazônica. Cyperus é o segundo maior gênero da família, com cerca de 950 espécies amplamente distribuídas. Cyperus subg. Pycreus possui cerca de 120 espécies com distribuição Pantropical. As espécies deste subgênero são caracterizadas pela combinação de ovário bicarpelar, estilete bífido, aquênios lateralmente achatados e espiguetas plurifloras. O presente trabalho teve como objetivo realizar um estudo taxonômico de Cyperus subg. Pycreus como forma de contribuir ao conhecimento da diversidade do subgênero no Brasil. O trabalho foi desenvolvido com base em levantamento bibliográfico, coletas, revisão de herbários e análises morfológicas. Foi reconhecida a ocorrência de 14 espécies (C. barrosianus, C. capillifolius, C. flavescens, C. fugax, C. jaeggii, C. lanceolatus, C. lorentzianus, C. macrostachyos, C. megapotamicus, C. mundii, C. niederleinianus, C. polystachyos, C. pumilus e C. unioloides) e três novas espécies foram descritas (C. tuckerianus, Cyperus sp. 1 e Cyperus sp. 2). Para todas as espécies são fornecidas descrições, ilustrações, dados da distribuição, habitat, informações sobre floração e frutificação, além de características macro e micromorfológicas dos frutos. / Abstract: Cyperaceae is a large cosmopolitan family of monocotyledons. In Brazil, this is the third most representative family of the Pampa phytogeographic domain, being also representative in the Pantanal, Caatinga and Amazon Rainforest. Cyperus is the second largest genus of Cyperaceae, with about 950 species widely distributed. Cyperus subg. Pycreus has about 120 species with Pantropical distribution. The species of this subgenus are characterized by the combination of ovary bicarpelar, style bifid, achene laterally flattened, and by spikelets pluriflowered. The present work aimed to carry out a taxonomic study of Cyperus subg. Pycreus as a way to contribute to the knowledge of the subgenus diversity in Brazil. The work was developed based on bibliographical survey, collections in field, herbarium review and morphological analyzes. It was confirmed the occurrence of 14 species (C. barrosianus, C. capillifolius, C. flavescens, C. fugax, C. jaeggii, C. lanceolatus, C. lorentzianus, C. macrostachyos, C. megapotamicus, C. mundii, C. niederleinianus, C. polystachyos, C. pumilus and C. unioloides) and the description of three new species (C. tuckerianus, Cyperus sp. 1 and Cyperus sp. 2). For all species we provide descriptions, illustrations, distribution data, habitat, information on flowering and fruiting, and macro and micromorphological characteristics of the achenes.
25

Desenvolvimento da antera e do grão de pólen em espécies de Mapania Aubl. (Mapanioideae, Cyperaceae) /

Lopes, Fernanda Passarini. January 2016 (has links)
Orientadora: Alessandra Ike Coan / Coorientador: Marccus Vinícius da Silva Alves / Banca: Adelita Aparecida Sartori Paoli / Banca: Érika Amano / Resumo: Pseudomônade é o pólen predominante de Cyperaceae, resultante da microsporogênese simultânea tipo-Cyperaceae, onde a tétrade de micrósporos se torna secundariamente reduzida a uma mônade funcional devido à degeneração de três de seus quatro núcleos. Este pólen, morfologicamente, tem formato cuneiforme com uma ou mais aberturas. Porém, em alguns gêneros de Hypolytreae (Mapanioideae), ocorre um outro tipo de pólen, de natureza ainda dúbia, chamado de pólen tipo-Mapania. Este pólen é esférico e monoporado e já foi considerado uma mônade. No presente estudo, três espécies de Mapania (Hypolytreae, Mapanioideae) foram estudadas, a fim de descrever o desenvolvimento de suas anteras e de seus grãos de pólen, em microscopias de luz e eletrônicas de varredura e de transmissão, e comparar os resultados aqui obtidos com aqueles já existentes na literatura para Cyperaceae. Nas três espécies estudadas, constatou-se a formação da pseudomônade, como resultado da microsporogênese simultânea tipo-Cyperaceae, assim como já descrita para as demais espécies da família. Durante a microgametogênese, observou-se o englobamento dos três núcleos não-funcionais, em degeneração, pela intina. A morfologia da pseudomônade está relacionada ao arranjo central nos microsporângios ao longo da microgametogênese. A formação da exina ocorre durante a microsporogênese, a partir da esporopolenina secretada pelo tapete secretor. Esses resultados da formação da pseudomônade em Mapania reforçam o caráter sinapomórfico de Cyperaceae dentre as Poales / Abstract: Pseudomonad is the predominant pollen in Cyperaceae resulting from simultaneous microsporogenesis of the Cyperaceae-type in which the microspore tetrad becomes secondarily reduced to a functional monad due to degeneration of three of its four nuclei. Morphologically, this pollen presents wedge-shape with one or more apertures. However, in some genera of Hypolytreae (Mapanioideae), there is another pollen type, of unknown nature, termed Mapania-type pollen. This pollen is spherical and monoporate and already was considered a monad. In the present study, three species of Mapania (Hypolytreae, Mapanioideae) were studied in order to describe their anther and pollen grain development in light and both scanning and transmission electron microscopies, and compare the results obtained here with those already described in the literature for Cyperaceae. In all species studied, the pollen is a true pseudomonad as a result of simultaneous microsporogenesis of the Cyperaceae-type, as well as already described for other family taxa. During microgametogenesis, three non-functional nuclei, in degeneration, were involved by intine. Pseudomonad morphology was related to the central arrangement in the microsporangia through microgametogenesis. Exine formation occurred through microsporogenesis, from sporopollenin secreted by secretory tapetum. These results in Mapania reinforce the Cyperaceae sinapomorphic character in Poales / Mestre
26

Meiose invertida quiasmática e aquiasmática em plantas com cromossomos holocinéticos

Corina Carneiro de Cabral, Gabriela 31 January 2010 (has links)
Made available in DSpace on 2014-06-12T15:02:56Z (GMT). No. of bitstreams: 2 arquivo2080_1.pdf: 693319 bytes, checksum: 06ba5e0a91cf68ac0aaa48e656e42501 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2010 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / De acordo com a extensão do cinetócoro, os cromossomos podem ser divididos em monocêntricos, com cinetócoro localizado, e holocinéticos, com cinetócoro difuso. Diversos organismos com cromossomos holocinéticos, incluindo todas as plantas com este tipo cromossômico, apresentam uma meiose bastante peculiar, na qual são observadas 2n cromátides individualizadas na prófase II. Este tipo de meiose é denominado meiose invertida ou pós-reducional, baseado na hipótese de que a segregação das cromátides irmãs na anáfase I seria a causa das cromátides individualizadas na prófase II. Neste trabalho, foi analisado o curso meiótico de duas espécies de Cyperaceae, Rhynchospora pubera (2n = 10) e R. tenuis (2n = 4), que apresentam meiose quiasmática e aquiasmática, respectivamente. Foram encontrados fortes indícios de meiose invertida nas duas espécies, uma vez que os cinetócoros das cromátides irmãs apresentaram ligação anfitélica com o fuso na metáfase I tanto nos univalentes de R. tenuis como nos bivalentes de R. pubera. A ligação anfitélica dos cinetócoros irmãos é um pré-requisito para a segregação das cromátides irmãs na anáfase I. Adicionalmente, foram investigados neste trabalho dois aspectos da prófase I que poderiam interferir na formação de quiasmas na meiose de R. tenuis. Neste caso, foi avaliada a presença de Rad51, uma enzima que atua no reparo de quebras na dupla fita de DNA, necessária para a formação do quiasma, e de ASY1, uma das proteínas que compõe o elemento axial dos cromossomos meióticos e é necessária para a sinapse. A formação de quebras na dupla fita de DNA na prófase I parece ocorrer normalmente, com base na distribuição dos sinais da recombinase Rad51. No entanto, a imunolocalização da ASY1 revelou a formação de filamentos anormais, com aspecto borrado, em R. tenuis, contrastando com os filamentos nítidos observados em R. pubera. A análise da distribuição dos sítios de DNAr 5S e das bandas CMA+ confirmou que a meiose de R. tenuis é assináptica. Baseado nos defeitos sinápticos observados em R. tenuis, é possível que a ausência de quiasmas deva-se a uma falha na formação do complexo sinaptonêmico, uma vez que as etapadas inicias de recombinação estão presentes na espécie
27

The anatomy and ecophysiology of Mariscus congestus from three different habitats in the Albany and Bathurst districts of the Eastern Cape, investigated under field and laboratory conditions

Sonnenberg, Bernd Jürgen January 1992 (has links)
An investigation of the anatomy and gas exchange characteristics of Mariscus congestus in three different habitats was undertaken in order to establish whether M. congestus from the three different habitats displayed any ecotypic responses when placed in a new similar environment. It was hoped that the results of this investigation would yield evidence that would support the ecotype concept similar to the investigations of Milner and Hiesey (1964), Green (1969) and Slayter and Ferrar (1977). On the basis of the site leaf anatomy, M. congestus investigated at the coast (site 1) differed in many respects from the inland plants (sites 2 and 3). These differences suggest that the coastal plants may have undergone a slight ecotypic divergence from the inland plants. The anatomical investigation also suggested that the leaves of M. congestus from all three sites may either be C₄ NADP-ME or PCK and that all had typical Chlorocyperiod anatomy. The habitat microclimates at sites 1-3 had different light and water regimes. There were no significant differences between the 12 month temperature environments of the three sites. There was however, a minor difference between the coastal (high temperature) and the inland (lower temperature) sites. M. congestus at the three sites had significantly different CO₂ assimilation rates, transpiration and stomatal conductance in response to the differing habitat microclimates. The water use efficiency of the sites were however, similar. Site 1 attained the highest CO₂ assimilation rates, transpiration, stomatal conductance, and water use efficiency and site 3 the lowest. Under similar conditions the gas exchange data for the potted plants indicated that M. congestus from the different sites was typically C₄. The optimal photosynthetic temperatures of all the sites was above 30°C and they did not show significant inhibition of CO₂ assimilation by different oxygen concentrations. The results of the laboratory investigation of the potted plants suggested that the only site-specific (ecotypic) response of M. eongestus was the light intensity at which the plants from the different sites were light saturated. The light and temperature response of field plants under field conditions was not comparable to the light and temperature response of potted plants under laboratory conditions. This may have been due to the field results being obtained under differing water and soil nutrient regimes. The potted plants may also have had a reduced root mass compared to their field counterparts and the potted plants may have also have become root bound. Under field conditions the plants had differing light saturation points and optimal photosynthetic temperatures compared to the potted plants. This investigation thus did not support the hypothesis stated in this thesis. The data in this investigation thus may indicate that plants with as diverse habitats as Mariscus congestus that are removed from their natural habitats display rapid changes in gas exchange characteristics in response to their new microclimates, with few ecotypic physiological characteristics of the old habitat being retained.
28

Systematics and Phylogeography of "Carex capitata" Complex (Cyperaceae)

Villaverde Hidalgo, Tamara M. January 2012 (has links)
Only thirty known species have populations at high latitudes in both hemispheres, this is, a bipolar distribution. Five of them belong to the genus Carex. Before attempting to elucidate the origins of such distributions, we need to resolve taxonomical problems that are typically encountered in such species. We focus on the Carex capitata complex, which includes Carex arctogena as a bipolar species, in worldwide scope sampling. A morphometric study and phylogenetic analyses based on maximum parsimony, Bayesian inference and Statistical Parsimony have revealed: a) C. capitata and C. arctogena are different species; b) C. anctarctogena is a synonym of C. arctogena and c) a great biodiversity previously undetected in western North America that could lead to the description of three new taxa (“Carex cayouetteana”, Carex sp. nov. 1 and 2) comprised in the so called “C. cayouetteana” lineage. More studies are needed in some C. capitata samples from Russia that appears in the molecular analyses in a strongly supported clade.
29

O gênero Carex L.(Cyperaceae) no Rio Grande do Sul, Brasil

Silveira, Gabriela Hoff January 2010 (has links)
(O gênero Carex L. (Cyperaceae) no Rio Grande do Sul, Brasil) - O gênero Carex L. inclui cerca de 2200 espécies distribuídas principalmente em regiões frias e temperadas. Foi realizado o levantamento deste gênero no Rio Grande do Sul com base em coletas, revisão de herbários e de bibliografia. Foram confirmadas para o Estado: C. aureolensis Steud., C. bonariensis Desf., C. brasiliensis A.St.-Hil., C. brongniartii Kunth, C. chilensis Brongn., C. feddeana H. Pfeiff., C. fuscula ssp. catharinensis (Boeck.) Luceño & Alves, C. longii ssp. meridionalis (Kük.) Luceño & M. Alves, C. phalaroides ssp. crassiflora (Kük.) Luceño & M. Alves, C. phalaroides ssp. moesta (Kunth) Luceño & M. Alves, C. phalaroides ssp. paraguayensis (Maury) Luceño & M. Alves, C. phalaroides Kunth ssp. phalaroides, C. polysticha Boeck., C. purpureovaginata Boeck., C. sellowiana Schltdl., C. seticulmis Boeck., C. sororia Kunth, C. tweediana Nees ex Hooker, C. uruguensis Boeck. e C. vixdentata (Kük.) G.A. Wheeler. É fornecida uma chave analítica para a identificação dos táxons confirmados, bem como descrições, ilustrações e dados sobre distribuição geográfica geral e no Rio Grande do Sul. / (The genus Carex L. (Cyperaceae) in Rio Grande do Sul, Brazil) - The genus Carex L. includes about 2200 species mainly distributed in cold and temperate regions. A survey of the genus Carex in Rio Grande do Sul was carried out based on field collections, revision of herbaria and literature. The following taxa were confirmed to the State: C. aureolensis Steud., C. bonariensis Desf., C. brasiliensis A.St.-Hil., C. brongniartii Kunth, C. chilensis Brongn., C. feddeana H. Pfeiff., C. fuscula D’Urv. ssp. catharinensis (Boeck.) Luceño & Alves, C. longii ssp. meridionalis (Kük.) Luceño & M. Alves, C. phalaroides ssp. crassiflora (Kük.) Luceño & M. Alves, C. phalaroides ssp. moesta (Kunth) Luceño & M. Alves, C. phalaroides ssp. paraguayensis (Maury) Luceño & M. Alves, C. phalaroides Kunth ssp. phalaroides, C. polysticha Boeck., C. purpureovaginata Boeck., C. sellowiana Schltdl., C. seticulmis Boeck., C. sororia Kunth, C. tweediana Nees ex Hooker, C. uruguensis Boeck. and C. vixdentata (Kük.) G.A. Wheeler. An analytical key to the identification of the confirmed taxa is provided as well as descriptions, illustrations and data on geographical distribution and habitat.
30

O Gênero Eleocharis R.Br. (Cyperaceae) no Rio Grande do Sul, Brasil / The genus Eleocharis R. Br. (Cyperaceae) in Rio Grande do Sul, Brazil

Trevisan, Rafael January 2005 (has links)
O estudo taxonômico do gênero Eleocharis R. Br. para o Rio Grande do Sul foi desenvolvido através dos métodos tradicionais em taxonomia. Os dados foram obtidos através da bibliografia, revisão de herbários regionais e coleta de exemplares a campo. O gênero está representado no Rio Grande do Sul por 27 espécies: Eleocharis acutangula (Roxb.) Schult., E. bonariensis Nees, E. contracta Maury, E. dunensis Kük., E. elegans (Kunth) Roem. & Schult., E. filiculmis Kunth, E. flavescens (Poir.) Urb., E. geniculata (L.) Roem. & Schult., E. interstincta (Vahl) Roem. & Schult., E. loefgreniana Boeck., E. maculosa (Vahl) Roem. & Schult., E. minima Kunth var. minima, E. montana (Kunth) Roem. & Schult., E. montevidensis Kunth, E. nudipes (Kunth) Palla, E. obtusetrigona (Lindl. & Nees) Steud., E. ochrostachys Steud., E. parodii Barros, E. aff. quinquangularis, E. quinquangularis Boeck., E. rabenii Boeck., E. radicans (Poir.) Kunth, E. sellowiana Kunth, E. squamigera Svenson, E. subarticulata (Nees) Boeck., E. viridans Kük. e Eleocharis sp. O trabalho apresenta descrições, ilustrações, dados sobre distribuição geográfica, habitat e períodos de floração e frutificação das espécies, além de uma chave dicotômica para diferenciá-las. / The taxonomic study of genus Eleocharis R. Br. for Rio Grande do Sul State was developed through of traditional methods of comparative morphology in taxonomy. The data were obtained through bibliography, revision of regional herbaria and field expedition for specimens collection. The genus is represented in Rio Grande do Sul by 27 species: Eleocharis acutangula (Roxb.) Schult., E. bonariensis Nees, E. contracta Maury, E. dunensis Kük., E. elegans (Kunth) Roem. & Schult., E. filiculmis Kunth, E. flavescens (Poir.) Urb., E. geniculata (L.) Roem. & Schult., E. interstincta (Vahl) Roem. & Schult., E. loefgreniana Boeck., E. maculosa (Vahl) Roem. & Schult., E. minima Kunth var. minima, E. montana (Kunth) Roem. & Schult., E. montevidensis Kunth, E. nudipes (Kunth) Palla, E. obtusetrigona (Lindl. & Nees) Steud., E. ochrostachys Steud., E. parodii Barros, E. aff. quinquangularis, E. quinquangularis Boeck., E. rabenii Boeck., E. radicans (Poir.) Kunth, E. sellowiana Kunth, E. squamigera Svenson, E. subarticulata (Nees) Boeck., E. viridans Kük. and Eleocharis sp. Descriptions, illustrations and an analytical key for species are provided, as well as data about their geographic distribution, habitat and flowering/fruiting periods.

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