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1
Moniz, de Sa Mario. "The evolution of angiosperm actin genes." Thesis, University of Ottawa (Canada), 1995. http://hdl.handle.net/10393/10062.
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Forty-four actin genes from five angiosperm species, whose evolutionary relationships are well characterized, were PCR-cloned and sequenced. Phylogenetic analysis of 34 of these actin genes, along with those previously published, indicate that plant actin genes are monophyletic and underwent a rapid radiation early in land plant evolution. Six sets of putative orthologues have been identified and their sequences were used to calculate rates of evolution. The synonomous rate of substitution $(5.44\times10\sp{-9}$/site/year) is similar to that of other nuclear protein-encoding genes but the non-synonomous rate $(0.13\times10\sp{-9}$/site/year) is 4-10 times higher than that of vertebrate actin genes. Relative-rate tests do not support a faster rate in plants than in vertebrates. Evidence is also provided that some members of the actin multigene family in maize are undergoing gene conversion. Finally, we show that some plant actin genes have undergone intron loss probably as a consequence of a gene conversion event between the genomic copy and the reverse transcript.
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Hayes, Peta Angela. "Cretaceous angiosperm leaf floras from Antarctica." Thesis, University of Leeds, 1999. http://etheses.whiterose.ac.uk/21096/.
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Late Cretaceous angiosperm leaf floras from the Antarctic Peninsula have been studied and described for the first time. The Hidden Lake Formation (Coniacian) and Santa Marta Formation (Santonian-early Campanian) floras were preserved within shallow marine strata exposed on James Ross Island. This area was located at approximately 65°S during the Late Cretaceous. These fossils represent the remains of vegetation growing in the southern high latitudes on an emergent volcanic arc. The plants probably grew on the delta top and along the edge of streams. The leaf fossils are preserved as isolated and fragmentary impressions and although cuticular anatomy is not present, the angiosperm leaves show the well-preserved fine detail of leaf architecture. These leaves have been drawn and described using Hickey's (1979) terminology. Attempts were made to group the leaves into morphotypes to allow reconstruction of floral composition and palaeoclimates. Several methods of grouping leaves were used, including visual grouping, Single character classification, and multivariate approaches. Multivariate statistical analysis allowed many characters to be considered simultaneously and even allowed fragmentary specimens, which were harder to deal with visually, to be evaluated. Clustering analysis was performed and dendrograms were produced for the Hidden Lake Formation and Santa Marta Formation floras, which were used in conjunction with visual assessments to group leaves with distinct morphologies into morphotypes. A total of 41 morphotypes were identified, 30 in the Hidden Lake Formation flora and 31 in the Santa Marta Formation flora, with 20 in common. Detailed descriptions of each morphotype and representative illustrations are presented. Comparisons have been drawn with fossil and living angiosperm leaves. Architectural characteristics suggest that some of the leaves may have affinities with the Cunoniaceae, Lauraceae, Sterculiaceae, Nothofagaceae, Myrtaceae and Elaeocarpaceae. If botanical affinities can be confirmed, many of these occurrences would extend the ranges of angiosperm taxa on the Antarctic Peninsula. Palaeoclimatic interpretation of the leaf floras included comparisons with possible nearest living relatives, analysis of leaf margins, shapes and sizes, and the application of simple linear regression and multiple linear regression models. The climate is considered to have been warm and moist. Mean annual temperature estimates of 12-21°C were provided for the Hidden Lake Formation flora and 14-23°C for the Santa Marta Formation flora. Evaluation of published data suggests that these Coniacian-early Campanian leaf floras may reflect the warmest time during the Cretaceous in Antarctica.
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Penny, J. H. J. "Early Cretaceous angiosperm pollen from Egypt." Thesis, University of Cambridge, 1986. https://www.repository.cam.ac.uk/handle/1810/273106.
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Silveira, Carina Lima da. "Características vegetativas e reprodutivas das plantas e fatores abióticos do meio e suas relações com a alocação de biomassa floral e a seleção sexual em angiospermas." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316105.
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Orientador: Marlies SazimaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: As plantas são organismos sésseis que estão à mercê do estresse ambiental. As flores são estruturas fundamentais na evolução das angiospermas, pois através delas ocorre a reprodução sexuada. Para isto, as flores exibem estratégias que auxiliam a planta a obter melhor sucesso reprodutivo. Animais visitam flores em busca de recursos, no entanto, ao transportar grãos de pólen entre os indivíduos da mesma espécie vegetal, atuam como mediadores no processo de seleção sexual, importante força na evolução florai. Fatores ecológicos que afetam a relação entre plantas e polínizadores podem influenciar a evolução das estratégias reprodutivas das espécies. Fatores abióticos, a distribuição espacial, o tamanho populacional e a história de vida das plantas podem modificar a abundância e a distribuição dos recursos para os polínizadores, alterando padrões de transporte de pólen, fluxo gênico e pressões seletivas responsáveis pela evolução floral. Este trabalho busca compreender a diversidade das estratégias reprodutivas em diferentes formações vegetais tropicais, a modulação por características vegetativas e reprodutivas das plantas e abióticas do meio na alocação de recursos como, também, verificar a existência de consistência biogeográfica dos padrões alométricos em relação as estratégias reprodutivas das plantas. O estudo foi realizado em áreas de vegetação tropical, sendo uma área de Floresta Atlântica, uma área de Cerrado, ambas no estado de São Paulo e uma área de Campo Rupestre, no estado de Minas Gerais, permitindo a comparação da variação da biomassa floral entre as três formações vegetais e entre angiospermas tropicais com particularidades morfológicas relacionadas às áreas de coleta e dados bibliográficos de espécies extra-tropicais. A riqueza de formas vegetais e de ambientes nas regiões tropicais atua na modulação da interação entre plantas e polínizadores, influenciando na variação da biomassa floral e nas características vegetativas e reprodutivas das espécies. As alometrias positivas e a isometria encontradas nas floras tropicais e extra-tropícats em relação ao crescimento da biomassa floral apontam para a presença e desenvolvimento de características sexuais secundarias como importantes ferramentas na permanência e sucesso da reprodução cruzada. Características vegetativas e reprodutivas influenciam na variação interespecífica da biomassa floral e que a função masculina da flor teria forte impacto na evolução das características florais, independentemente da ligação filogenética entre as angiospermas, ressaltando a necessidade de teorias que permitam uma síntese destas relações.
Abstract: Plants are sessile organisms exposed to the effects of environmental stress. The flowers are fundamental structures in the evolution of angiosperms, because through them is sexual reproduction. For this, the flowers exhibit strategies that help the plant to achieve better reproductive success. Animals visit flowers in search of resources, however, to carry pollen between individuals of the same plant species, act as mediators in the process of sexual selection, major force in floral evolution. Ecological factors affecting the relationship between plants atid pollinators may influence the evolution of reproductive strategies of species. Abiotic factors, spatial distribution, population size and life history of plants can modify the abundance and distribution of resources for pollinators by changing patterns of pollen transfer, gene flow and selective pressures responsible for floral evolution. This work seeks to understand the diversity of reproductive strategies in different tropical vegetation types, the modulated vegetative and reproductive features of plants and the abiotic environment in resource allocation as well, check for consistency biogeographical of allometric patterns in reproductive strategies in relation to plants. The study was conducted in areas of tropical vegetation, with an area of Atlantic Rain Forest, an area of Savannah, both in the state of Sao Paulo and an area of Campo Rupestre, in the state of Minas Gerais, allowing the comparison of variation among floral biomass the three vegetation types and between tropical angiosperm morphological peculiarities related to the areas of collection and bibliographic data of extra-tropical species. The richness of plant forms and environments in tropical acts in modulating the interaction between plants and pollinators, influencing the variation of biomass in the floral and vegetative and reproductive characteristics of species. The positive allometry and isometry floras found in tropical and extra-tropical growth over the floral biomass indicate the presence and development of secondary sexual characteristics as important tools in the permanence and success of cross-breeding. Vegetative and reproductive characteristics influence the interspecific variation of floral biomass and that the function of male flowers have a strong impact on the evolution of floral traits, regardless of the phylogenetic connection between the angiosperms, highlighting the need for theories that allow a synthesis of these relationships.
Doutorado
Ecologia
Doutor em Ecologia
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Oakley, Daniel. "Cretaceous Angiosperm Woods; Insights into Svstematics, Ecology and Biogeography." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520229.
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Griffith, G. S. "Fungal community structure and development in attached angiosperm twigs." Thesis, Cardiff University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305126.
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Hirst, Jevon Edward. "The ecology and physiology of endophytes of angiosperm stems." Thesis, Cardiff University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265814.
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Guignard, Maite Stephanie. "Ecological consequences of angiosperm genome size and macronutrient availability." Thesis, Queen Mary, University of London, 2017. http://qmro.qmul.ac.uk/xmlui/handle/123456789/24632.
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Genome size (GS) is a fundamental trait influencing cellular, developmental and ecological parameters, and varies c. 2400- fold in angiosperms. This astonishing range has the potential to influence a plant's nutrient demands, since nucleic acids are amongst the most phosphate and nitrogen demanding cellular biomolecules, and hence its ability to grow and compete in environments where macronutrients are limited. Angiosperm GS are strongly skewed towards small genomes, despite the prevalence of polyploidy in the ancestry of most if not all angiosperm lineages. This thesis examines the hypothesis that large genome sizes are costly to build and maintain and that angiosperm species with large GS are constrained by nitrogen and phosphate limitation. It untangles the interactions between GS, polyploidy and competition in plant communities, and examines how herbivory and GS play a role in plant productivity, measured as above-ground biomass. The hypothesis that large GS are costly was approached by analysing: 1) plant communities growing under different macronutrient conditions at the Park Grass Experiment (Rothamsted, UK); 2) plant communities under different conditions of macronutrient limitation and insect, mollusc, and rabbit herbivory at Nash's Field in Silwood Park (UK); and, 3) Ellenberg's indicator values which represent the realised niche of a species in terms light, water, and soil fertility. Support for the hypothesis was found in all experiments. The range of analyses show that angiosperm plants with large genomes (e.g. 1C-value > 5 pg) are indeed under greater macronutrient limitation in comparison to plants with small genomes, and that it is polyploid plants with large GS which are the most competitive when macronutrient resources are plentiful. In terms of herbivory, the key finding is a highly significant negative association between GS and rabbit herbivory. A species' realised niche for soil fertility was found to show a positive association with its GS. Overall the thesis shows that angiosperm GS plays a central role in plant community composition and responses to macronutrient conditions, and potentially on higher ecosystem processes through associations at different trophic levels.
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Sanderson, Michael, and Michelle McMahon. "Inferring angiosperm phylogeny from EST data with widespread gene duplication." BioMed Central, 2007. http://hdl.handle.net/10150/610375.
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BACKGROUND:Most studies inferring species phylogenies use sequences from single copy genes or sets of orthologs culled from gene families. For taxa such as plants, with very high levels of gene duplication in their nuclear genomes, this has limited the exploitation of nuclear sequences for phylogenetic studies, such as those available in large EST libraries. One rarely used method of inference, gene tree parsimony, can infer species trees from gene families undergoing duplication and loss, but its performance has not been evaluated at a phylogenomic scale for EST data in plants.RESULTS:A gene tree parsimony analysis based on EST data was undertaken for six angiosperm model species and Pinus, an outgroup. Although a large fraction of the tentative consensus sequences obtained from the TIGR database of ESTs was assembled into homologous clusters too small to be phylogenetically informative, some 557 clusters contained promising levels of information. Based on maximum likelihood estimates of the gene trees obtained from these clusters, gene tree parsimony correctly inferred the accepted species tree with strong statistical support. A slight variant of this species tree was obtained when maximum parsimony was used to infer the individual gene trees instead.CONCLUSION:Despite the complexity of the EST data and the relatively small fraction eventually used in inferring a species tree, the gene tree parsimony method performed well in the face of very high apparent rates of duplication.
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Pirone, Cary L. "Bilirubin: an Animal Pigment in the Zingiberales and Diverse Angiosperm Orders." FIU Digital Commons, 2010. http://digitalcommons.fiu.edu/etd/336.
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Strelitziaceae is a tropical monocot family comprising three genera and seven species: Ravenala Adans and Phenkospermum Endl., which are monotypic, and five species of Strelitzia Aiton. All species produce woody capsular fruits that contain vibrantly colored arillate seeds. Arils of the Strelitzia species are orange, those of Phenakospermum are red, and those of Ravenala are blue. Unlike most plant pigments, which degrade after cell death, aril pigments in the family persist for decades. Chemical properties of the compounds are unusual, and do not match those of known pigment classes (carotenoids, flavonoids, betalains, and the chlorophylls). I isolated the orange pigment from the arils of Strelitzia nicolai, and performed HPLC-ESMS, UV-visible, 1H NMR and 13C NMR analyses to determine its chemical structure. These data indicated the pigment was bilirubin-IX, an orange-yellow tetrapyrrole previously known only in mammals and some other vertebrates as the breakdown product of heme. Although related tetrapyrroles are ubiquitous throughout the plant kingdom and include vital biosynthetic products such as chlorophyll and phytochromobilin, this is the first report of bilirubin in a plant, and evidence of an additional biosynthetic pathway producing orange coloration in flowers and fruits.
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Kilaru, Aruna, Xia Cao, Ha-Jung Sung, Keithanne Mockaitis, and John B. Ohlrogge. "A Conserved Regulation of Oil Biosynthesis in Avocado, a Basal Angiosperm." Digital Commons @ East Tennessee State University, 2013. https://dc.etsu.edu/etsu-works/4807.
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Avocado is an economically important crop with ~ 60-70 % oil, by dry weight, in its fruit mesocarp tissue. The steady increase in global demand for avocado (9% per year) has driven interest to identify the biochemical and molecular factors that regulate its triacylglycerol (TAG, oil) biosynthesis. Using 454- and Illumina-based RNA-Seq approaches, we examined the transcriptional basis for TAG biosynthesis in developing mesocarp of avocado, in relation to other seed and non-seed tissues. Deep transcriptional profiling data allowed us to identify several transcripts that were differentially represented between the early and late developmental stages of mesocarp. Additionally, in all oil-rich tissues analyzed, irrespective of the species, an increased expression was noted for genes mostly associated with fatty acid biosynthesis in plastid, but much less increase in those for TAG assembly in the endoplasmic reticulum. Transcripts associated with hexose metabolism in plastid also showed higher expression, relative to cytosol; this is likely associated with the need for high pyruvate flux directed toward plastid fatty acid synthesis. Moreover, WRINKLED1 transcription factor, a regulatory element associated with oil biosynthesis in seed and non-seed tissues of monocot and dicot plants, was identified in avocado as well. Our studies point to distinctive modes of regulation of fatty acid biosynthesis and TAG assembly that are conserved in both seed and non-seed oil-rich plants. In addition to improving avocado oil production, our study will lead to understanding regulation of oil biosynthesis in coordination with fruit development and identification of ways to generate oil-rich bioenergy crops; a direct implication for the science & society. This study provides an evolutionary insight into conserved nature of oil biosynthesis in a basal angiosperm (avocado) in relation to a monocot (oil palm) and a dicot (brassica). This research will lead to publications for students, sustain existing collaborations (Israel, CA, FL avocado researchers) and generate external funds.
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Thorogood, Christopher John. "Host Specificity and Speciation in the Holoparasitic Angiosperm Orobanche Minor sm. (Orobanchaceae)." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.499944.
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Kilaru, Aruna, Xia Cao, Parker B. Dabbs, Ha-Jung Sung, Mahbubur Rahman, Nicholas Thrower, Greg Zynda, et al. "Oil Biosynthesis in a Basal Angiosperm: Transcriptome Analysis of Persea Americana Mesocarp." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etsu-works/4748.
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The mechanism by which plants synthesize and store high amounts of triacylglycerols (TAG) in tissues other than seeds is not well understood. The comprehension of controls for carbon partitioning and oil accumulation in nonseed tissues is essential to generate oil-rich biomass in perennial bioenergy crops. Persea americana (avocado), a basal angiosperm with unique features that are ancestral to most flowering plants, stores ~ 70 % TAG per dry weight in its mesocarp, a nonseed tissue. Transcriptome analyses of select pathways, from generation of pyruvate and leading up to TAG accumulation, in mesocarp tissues of avocado was conducted and compared with that of oil-rich monocot (oil palm) and dicot (rapeseed and castor) tissues to identify tissue- and species-specific regulation and biosynthesis of TAG in plants.
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Silcock, Deborah J. "Aspects of cellular development in relation to the deposition of oil reserves during embryogenesis in Brassica napus L., cv. jet neuf (oil seed rape)." Thesis, Cardiff University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.232880.
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Hearne, Sarah Jane. "Morphological, physiological and molecular interactions between maize and the parasitic angiosperm Striga hermonthica." Thesis, University of Sheffield, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369935.
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Toomey, Nicola. "Investigation of the phylogenetic utility of Cycloidea-like genes in various angiosperm lineages." Thesis, University of Reading, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.414722.
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Kilaru, Aruna, Xia Cao, P. B. Dabbs, MMd Rahman, and J. B. Ohlrogge. "Transcriptome Analysis Reveals Mostly Conserved Pathway for Oil Biosynthesis in a Basal Angiosperm." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etsu-works/4800.
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Fanton, Jean Carlo Mari 1983. "Reconstruindo as florestas tropicais úmidas do eoceno-oligoceno do sudeste do Brasil (Bacias de Fonseca e Gandarela, Minas Gerais) com folhas de fabaceae, myrtaceae e outras angiospermas : origens da Mata Atlântica." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287244.
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Orientador: Fresia Soledad Ricardi Tores BrancoTese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociências
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Resumo: Folhas isoladas de angiospermas preservadas em depósitos fluvio-lacustres das bacias de Fonseca e Gandarela foram analisadas visando reconstruir o paleoambiente. Angiospermas são bons indicadores climáticos, pois a distribuição de suas espécies no espaço/tempo e influenciada pelo clima. Localizadas no centro-sul de Minas Gerais, as bacias de Fonseca e Gandarela são grabens encravados no embasamento Pré-Cambriano, depositados nos intervalos Neoeoceno-Eoligoceno e Neoeoceno- Eomioceno (respectivamente), segundo dados paleológicos. Como métodos, alem da morfotipificação, características arquiteturais informativas permitiram identificações taxonômicas com base apenas em folhas. Para estimar as paleotemperaturas, aplicou-se a Analise da Margem Foliar (LMA) utilizando a relação entre a proporção de espécies arbóreas "dicotiledôneas" com margens lisas (pE) e a media anual de temperatura (MAT). Antes, a habilidade de modelos sul-americanos foi testada em florestas atlânticas do sudeste. Devido à pEs altas (0,78-0,87), as temperaturas dos locais quentes-baixos (MAT ? 23°C) foram estimadas corretamente, mas o erro foi maior nos locais frios-elevados (MAT ? 22°C, 610-890 m). Mesmo que linhagens obrigatoriamente lisas estiveram super-representadas tanto nos locais quentes quanto frios (em media 38% das espécies/local), o desenvolvimento de terras altas desde o Neocretaceo e Cenozóico no sudeste inviabiliza hipóteses de tempo insuficiente para a evolução de margens denteadas nas angiospermas adaptadas a altitude. Para Fonseca (40 morfotipos) e Gandarela (20) foram obtidas pEs tão altas (0,90 e 0,95) quanto às de florestas equatoriais amazônicas atuais. MATs ? 24,7°C foram reconstruídas pela maioria dos modelos (em media ?27-28°C), faixa megatermica hoje registrada principalmente em terras-baixas do norte e nordeste do Brasil. Mais da metade dos 25 morfotipos aqui descritos foram identificados em famílias tropicais, como Lauraceae (FS06, GR03 e GR09), Fabaceae (FS01-03, FS05, FS09 e GR08), Combretaceae (FS08) e Myrtaceae (FS11-13 e GR02). Todas são linhagens com uma longa historia evolutiva (no mínimo desde o Paleoceno-Eoceno) no norte (Fabaceae e Lauraceae) e no sul (Myrtaceae) da America do Sul, expondo um antigo legado de tropical idade e influencia floristica mista (boreal-laurasiana e austral-antartica). Hoje no sudeste, tais famílias controlam boa parte dos recursos ecológicos na Mata Atlântica e provavelmente já o faziam nas florestas do Neopaleogeno. Devido à composição e certas condições ambientais compartilhadas, as florestas ombrofilas do compartimento sul da Mata Atlântica (inclusive a Floresta Ombrofila Mista, FOM) são analogias modernas parcialmente comparáveis com Fonseca e Gandarela: temperaturas e pluviosidade elevadas mantendo um dossel sempre-verde e multiestratificado, dominado por angiospermas (Myrtaceae, Lauraceae e Fabaceae) e coníferas austrais (Podocarpaceae e Araucariaceae). Confirmam a reconstrução de florestas tropicais úmidas: (1) o conjunto fisionômico da Formação Fonseca (onde 40- 65% dos morfotipos avaliados têm ápice acuminado, 80-90% margens lisas e 50% notofilo-mesofilos) e (2) a presença de linhagens que demandam umidade e intolerantes ao frio, como podocarpaceas dacrydioides (Dacrydiumites) e mirtaceas como FS13 (identificado em Curitiba), exibindo uma folha acuminada 2× maior que da atual C. prismática, espécie endêmica da FOM. O cenário reconstruído se ajusta aos níveis superiores de CO2 atmosférico, maior zona tropical e invernos relativamente brandos do final do Paleogeno
Abstract: Isolated fossil angiosperm leaves preserved in fluvial-lacustrine deposits from the Fonseca and Gandarela basins were analyzed to reconstruct the paleoenvironment. Angiosperms are good climatic indicators since the species distribution in space/time is influenced by the climate. Located in central-southern part of the State of Minas Gerais, the Fonseca and Gandarela basins are grabens embedded in the Precambrian basement, deposited during the Late Eocene-Early Oligocene interval, according to palynological data. As methods, informative architecture characteristics allowed taxonomic identifications solely on the basis of leaves. To estimate paleotemperatures, the Leaf Margin Analysis (LMA) was applied, based on the relationship between the proportion of untoothed woody "dicot" species (pE) and mean annual temperature (MAT). Before, the ability of South American models was tested on modern sites of Atlantic forests from southeastern Brazil. Because of high pEs (0,78-0,87), temperatures of the low-elevation sites (MAT ? 23°C) were predicted accurately, but the error was greater in the high-elevation ones (MAT ? 22°C, 610-890 m). Although obligate untoothed lineages were richly represented in low and high-temperature sites (in average 38% of the species per site), the development of highlands in southeastern Brazil since the Late Cretaceous and Cenozoic invalidate hypotheses about an insufficient time to evolve teeth in angiosperms adapted to high-elevations. Both fossil floras Fonseca (40 morphotypes) and Gandarela (20) showed pEs (0,90 and 0,95) so high as observed in Amazonian equatorial rainforests. MATs ? 24,7°C were yielded for the majority of the models (in average ?27-28°C), isotherm today registered mainly in lowlands from northern Brazil. Over half of the morphotypes described were identified in families essentially tropical, such as Lauraceae (FS06, GR03 and GR09), Fabaceae (FS01-03, FS05, FS09 and GR08), Combretaceae (FS08) and Myrtaceae (FS11-13 and GR02). All these lineages have a long evolutionary history (since at least the Paleocene- Eocene) in the north (Fabaceae and Lauraceae) and south (Myrtaceae) of South America, revealing an antique legacy of tropicality and mixed floristic influence from boreal-laurasian and austral-Antarctic regions. Today, such families have controlled a major portion of the ecological resources in the Atlantic forests from southeastern Brazil probably retaining dominance since the Paleogene. Similar composition and some environmental aspects suggest that the rainforests from the southern Atlantic block (including Araucaria rainforest) are the closest living analogues to the Fonseca and Gandarela extinct vegetation: high temperatures and heavy rainfall sustaining an evergreen and multilayered canopy dominated by angiosperms (Myrtaceae, Lauraceae and Fabaceae) and austral conifers (Podocarpaceae and Araucariaceae). Additional evidence supporting the tropical rainforest hypothesis is: (1) the Fonseca Formation leaf physiognomy (40-65% of the morphotypes evaluated have drip tips, 80-90% untoothed margins and 50% are notophyll-mesophyll), and (2) the presence of water-demanding and coldintolerant lineages, such as dacrydioid podocarps (Dacrydiumites) and the Myrtaceae morphotype FS13 (identified as Curitiba), which bears an acuminate leaf 2× longer than the extant C. prismatica. The paleoenvironment reconstructed agree with the higher atmospheric CO2 levels, the wider Tropical zone and the relatively mild winters during the Late Paleogene
Doutorado
Geologia e Recursos Naturais
Doutor em Ciências
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Huber, Dezene P. W. "Responses of five species of coniferophagous bark beetles (Coleoptera: Scolytidae) to angiosperm bark volatiles." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/NQ61650.pdf.
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Zhang, Qing-He. "Olfactory recognition and behavioural avoidance of angiosperm non-host volatiles by conifer bark beetles /." Alnarp : Swedish Univ. of Agricultural Sciences (Sveriges lntbruksuniv.), 2001. http://epsilon.slu.se/avh/2001/91-576-5789-0.pdf.
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Wang, Hongshan. "Diversity of angiosperm leaf megafossils from the Dakota Formation (Cenomanian, Cretaceous), north western interior, USA." [Gainesville, Fla.] : University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE1000170.
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Thesis (Ph. D.)--University of Florida, 2002.Title from title page of source document. Document formatted into pages; contains viii, 395 p.; also contains graphics. Includes vita. Includes bibliographical references.
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Amaya, Iraida. "Centoradialis and the control of plant architecture." Thesis, University of East Anglia, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302230.
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Crifo, Camilla. "VARIATIONS IN ANGIOSPERM LEAF VEIN DENSITY HAVE IMPLICATIONS FOR INTERPRETING LIFE FORM IN THE FOSSIL RECORD." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1375987428.
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LeBourgeois, Taylor. "Understanding the Historical Diversification of Valerianacea." ScholarWorks@UNO, 2016. http://scholarworks.uno.edu/honors_theses/78.
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Ecologists and evolutionary biologists have long recognized that species diversity is unequally distributed among angiosperm lineages. For example, various plant clades found in the Andes have been proposed as examples of rapid radiations, and the Andes are recognized as one of the Earth’s biodiversity “hotspots”. Species within Valerianaceae, found in the South American Andes, appear to be an example of such a rapid radiation. Although much attention has been paid to the phylogeny of the South American species of Valerianaceae, there is still a great deal of uncertainty regarding species relationships. Several subgroups within the Andean Valerians have, either not been included, or poorly sampled in previous phylogenetic analyses. One example of such a group is section Porteria. Knowing the phylogenetic placement of this group would go a long way in our understanding of Andean biogeography, as well as morphological and floral evolution in Valerianaceae. In this study, I increase the sample size of section Porteria beyond what has been previously done. A number of genomic regions were amplified and sequenced for 6 species belonging to the section. Sequences were then aligned to previously published sequence data for homologous regions for other species in Valerianaceae. A “supermatrix” of 146 species was then analyzed using maximum parsimony. Resulting trees recovered a monophyletic section Porteria, however statistical support was weak for this conclusion. Although “supertrees” resulting from the analysis of “supermatrices” may be powerful tools for testing hypotheses concerning the evolution of species, there is still much work to be done on Valerianaceae.
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Torres, Manuel John. "Construction of an annotated sequence database to advance molecular genetic investigations of Triphysaria versicolor, a parasitic angiosperm /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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Smith, Michaela Madeleine 1972. "Maintenance of ultrastructural integrity during dehydration in a desiccation tolerant angiosperm as revealed by improved preservation techniques." Monash University, Dept. of Biological Sciences, 2002. http://arrow.monash.edu.au/hdl/1959.1/8323.
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Li, Shan [Verfasser]. "Predicting angiosperm tree mortality based on embolism resistance, cambium vitality and intervessel pit membrane thickness / Shan Li." Ulm : Universität Ulm, 2017. http://d-nb.info/1126579602/34.
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Zuccolo, Andrea, John Bowers, James Estill, Zhiyong Xiong, Meizhong Luo, Aswathy Sebastian, Jose Goicoechea, et al. "A physical map for the Amborella trichopoda genome sheds light on the evolution of angiosperm genome structure." BioMed Central, 2011. http://hdl.handle.net/10150/610149.
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BACKGROUND:Recent phylogenetic analyses have identified Amborella trichopoda, an understory tree species endemic to the forests of New Caledonia, as sister to a clade including all other known flowering plant species. The Amborella genome is a unique reference for understanding the evolution of angiosperm genomes because it can serve as an outgroup to root comparative analyses. A physical map, BAC end sequences and sample shotgun sequences provide a first view of the 870 Mbp Amborella genome.RESULTS:Analysis of Amborella BAC ends sequenced from each contig suggests that the density of long terminal repeat retrotransposons is negatively correlated with that of protein coding genes. Syntenic, presumably ancestral, gene blocks were identified in comparisons of the Amborella BAC contigs and the sequenced Arabidopsis thaliana, Populus trichocarpa, Vitis vinifera and Oryza sativa genomes. Parsimony mapping of the loss of synteny corroborates previous analyses suggesting that the rate of structural change has been more rapid on lineages leading to Arabidopsis and Oryza compared with lineages leading to Populus and Vitis. The gamma paleohexiploidy event identified in the Arabidopsis, Populus and Vitis genomes is shown to have occurred after the divergence of all other known angiosperms from the lineage leading to Amborella.CONCLUSIONS:When placed in the context of a physical map, BAC end sequences representing just 5.4% of the Amborella genome have facilitated reconstruction of gene blocks that existed in the last common ancestor of all flowering plants. The Amborella genome is an invaluable reference for inferences concerning the ancestral angiosperm and subsequent genome evolution.
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Suren, Haktan. "Sequence capture as a tool to understand the genomic basis for adaptation in angiosperm and gymnosperm trees." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/86383.
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Forest trees represent a unique group of organisms combined with ecological and economic importance. Owing to their random mating system and widespread geographical distribution, they harbor abundance genetic variation both within and among populations. Despite their importance, research in forest trees has been underrepresented majorly due to their large and complex genome and scarce funding. However, recent climate change and other associated problems such as insect outbreaks, diseases and stress related damages have urged scientists to focus more on trees. Furthermore, the advent in high-throughput sequencing technologies have allowed trees to be sequenced and used as reference genome, which provided deeper understanding between genotype and environment. Whole genome sequencing is still not possible for organisms having large genomes including most tree species, and it is still not feasible economically for population genomic studies which require sequencing hundreds of samples. To get around this problem, genomic reduction is required. Sequence capture has been one of the genomic reduction techniques enabled studying the subset of the DNA of interest. In this paper, our primary goal is to outline challenges, provide guidance about the utility of sequence capture in trees, and to leverage such data in genome-wide association analyses to find the genetic variants that underlie complex, adaptive traits in spruce and pine, as well as poplar. Results of this research will facilitate bridging the genomic information gap between trees and other organisms. Moreover, it will provide better understanding how genetic variation governs phenotype in trees, which will facilitate both marker assisted selection for improved traits as well as provide guidance to determine forest management strategies for reforestation to mitigate the effects of climate change.Ph. D.
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Ibarra-Laclette, Enrique, Alfonso Méndez-Bravo, Claudia Anahí Pérez-Torres, Victor A. Albert, Keithanne Mockaitis, Aruna Kilaru, Rodolfo López-Gómez, Jacob Israel Cervantes-Luevano, and Luis Herrera-Estrella. "Deep Sequencing of the Mexican Avocado Transcriptome, an Ancient Angiosperm with a High Content of Fatty Acids." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etsu-works/4749.
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Background: Avocado (Persea americana) is an economically important tropical fruit considered to be a good source of fatty acids. Despite its importance, the molecular and cellular characterization of biochemical and developmental processes in avocado is limited due to the lack of transcriptome and genomic information.
Results: The transcriptomes of seeds, roots, stems, leaves, aerial buds and flowers were determined using different sequencing platforms. Additionally, the transcriptomes of three different stages of fruit ripening (pre-climacteric, climacteric and post-climacteric) were also analyzed. The analysis of the RNAseqatlas presented here reveals strong differences in gene expression patterns between different organs, especially between root and flower, but also reveals similarities among the gene expression patterns in other organs, such as stem, leaves and aerial buds (vegetative organs) or seed and fruit (storage organs). Important regulators, functional categories, and differentially expressed genes involved in avocado fruit ripening were identified. Additionally, to demonstrate the utility of the avocado gene expression atlas, we investigated the expression patterns of genes implicated in fatty acid metabolism and fruit ripening.
Conclusions: A description of transcriptomic changes occurring during fruit ripening was obtained in Mexican avocado, contributing to a dynamic view of the expression patterns of genes involved in fatty acid biosynthesis and the fruit ripening process.
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Jerome, Cheryl Ann. "Evolutionary biology of the parasitic angiosperm Arceuthobium americanum (Viscaceae) as determined by population genetic analysis and infectivity experiments." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ62643.pdf.
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Zhang, Ya [Verfasser]. "The functional morphology of interconduit pit membranes in fresh and dehydrated xylem tissues of angiosperm species / Ya Zhang." Ulm : Universität Ulm, 2018. http://d-nb.info/1169747051/34.
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Bass, Katherine Ann. "Resource partitioning in the multi-species interaction between a host plant, a parasitic angiosperm and an insect herbivore." Thesis, University of Sussex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.666763.
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Sassi, Giovanna. "Evolutionary History Of The Angiosperm Npf1 Gene Subfamily: Duplications, Retention And Functional Implications For Root Symbioses And Development." ScholarWorks @ UVM, 2019. https://scholarworks.uvm.edu/graddis/1142.
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ABSTRACT
The success of land plants can be attributed to the evolution of beneficial associations between plant roots and soil microbes. Root-microbe mutualisms extend the range of plant nutrient acquisition delivered through the hyphal network of mycorrhiza, an ancient and widespread plant symbiosis, or by the more recent adaptive innovation of nitrogen-fixing nodule symbioses. A plant’s genetic toolkit governs its selection of beneficial symbionts and the developmental extent of these intimate interactions. However, the evolutionary origins and function for only a few symbiotic signaling components have been explored. The central aim of this dissertation is to resolve the evolutionary events that contributed two, novel genetic components for establishing root symbioses, NPF1B and NPF1C.
The Medicago truncatula (Mt) LATD/NIP/NPF1.7C transporter functions in root and nodule meristems and is a member of the large NPF1 gene subfamily. Here, I propose that LATD/NIP’s role in establishing nitrogen-fixing symbioses is derived from the ancient mycorrhizal signaling pathway. I used a comparative phylogenomic approach to investigate the evolutionary origins of the NPF1 gene across flowering plants and then asked whether diversifying or purifying selection forces influenced NPF1 gene retention. I postulated that such gene retention correlates with the adaptive traits of mycorrhizal or nitrogen-fixing root nodule symbiosis; to test this I measured trait correlation within my dataset. I found that the NPF1 phylogeny is comprised of five well-supported angiosperm clades, A, B, C, D1 and D2, that arose by successive duplications and have unequal gene retention. NPF1B is present as a single copy gene or lost entirely, while the other major NPF1 clades expanded to multiple genes within angiosperms. The NPF1A, B and C genes are under strong purifying selection while the NPF1D genes display positive, diversifying selection. My data revealed a statistically significant correlation of NPF1A, B, C, and D2, but not NPF1D1, gene retention with the ability of a species to form mycorrhizal associations. Additionally, the retention of the NPF1B, C, D1, D2, but not NPF1A, genes within a species is statistically correlated with its ability to form nitrogen-fixing symbiosis. Supporting this correlation, NPF1B genes are expressed in plant root tissues with and without mycorrhizal fungi yet available datasets failed to detect NPF1B expression in nodule tissues whereas the NPF1C genes are expressed in both symbiotic and non-symbiotic plant root tissues. In support of functional conservation, expression of legume LATD/NIP cDNAs from Cicer arietinum (Ca) and Lotus japonicus (Lj) restored, in part, the root and nodule defects of the Mtlatd mutant and resulted in the formation of peculiar hybrid lateral root-nodule structures while, in wild-type M. truncatula, significantly augmented root development. In L. japonicus, the disruption of LATD/NIP alters the number of lateral roots and nodules
My thesis data support the hypothesis for an ancestral NPF1 gene function in establishing mycorrhizal associations in angiosperms and, consequent to the monocot-eudicot divergence, co-opted this function for accommodating nitrogen-fixing symbioses in eudicots. Successive duplications then yielded the NPF1B and NPF1C genes that, by neofunctionalization and natural selection, further refined their roles in root organogenesis and symbiosis; a prerequisite for the evolution of nodule organs.
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Huang, Bing-Quan. "Isolation and characterization of embryo sacs and their component cells in a synergidless (Plumbago) and a synergid-bearing (Nicotiana) angiosperm /." Full-text version available from OU Domain via ProQuest Digital Dissertations, 1991.
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Burch, James N. "Interaction of the parasitic angiosperm cassytha filiformis L. (Lauraceae) with the exotic schinus terebinthifolius RADDI (Anacardiaceae) in southern Florida." FIU Digital Commons, 1997. http://digitalcommons.fiu.edu/etd/1943.
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Brazilian pepper (Schinus terebinthifolius) is an exotic shrub or small tree that has become well established as an invasive and highly competitive species through much of southern Florida. Love vine (Cassytha filiformis), a native parasitic plant, was noted parasitizing Brazilian pepper, apparently affecting its health. The objective of this study was to investigate the nature of this parasitic interaction in southern Florida. Brazilian pepper populations were studied to determine whether parasitism by love vine may affect growth and reproduction. Anatomical studies of love vine parasitizing Brazilian pepper determined physical aspects of the parasitic interaction at the cell and tissue level. Physiological aspects of this interaction were investigated to help describe love vine resource acquisition as a parasite on host Brazilian pepper plants, and as an autotrophic plant. An investigation of ecological aspects of this parasitic interaction was done to determine whether physical or biological aspects of habitats may contribute to love vine parasitism on Brazilian pepper. These studies indicated that: 1) parasitism by love vine significantly decreased growth and reproduction of Brazilian pepper plants; 2) anatomical and physiological investigations indicated that love vine was primarily a xylem parasite on Brazilian pepper, but that some assimilated carbon nutrients may also be acquired from the host; 3) love vine is autotrophic (i. e., hemiparasitic), but is totally dependent on its host for necessary resources; 4) the occurrence of love vine parasitism on Brazilian pepper is mediated by physical characters of the biological community.
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Naumann, Julia, Karsten Salomo, Joshua P. Der, Eric K. Wafula, Jay F. Bolin, Erika Maass, Lena Frenzke, et al. "Single-Copy Nuclear Genes Place Haustorial Hydnoraceae within Piperales and Reveal a Cretaceous Origin of Multiple Parasitic Angiosperm Lineages." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-132144.
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Extreme haustorial parasites have long captured the interest of naturalists and scientists with their greatly reduced and highly specialized morphology. Along with the reduction or loss of photosynthesis, the plastid genome often decays as photosynthetic genes are released from selective constraint. This makes it challenging to use traditional plastid genes for parasitic plant phylogenetics, and has driven the search for alternative phylogenetic and molecular evolutionary markers. Thus, evolutionary studies, such as molecular clock-based age estimates, are not yet available for all parasitic lineages. In the present study, we extracted 14 nuclear single copy genes (nSCG) from Illumina transcriptome data from one of the “strangest plants in the world”, Hydnora visseri (Hydnoraceae). A ~15,000 character molecular dataset, based on all three genomic compartments, shows the utility of nSCG for reconstructing phylogenetic relationships in parasitic lineages. A relaxed molecular clock approach with the same multi-locus dataset, revealed an ancient age of ~91 MYA for Hydnoraceae. We then estimated the stem ages of all independently originated parasitic angiosperm lineages using a published dataset, which also revealed a Cretaceous origin for Balanophoraceae, Cynomoriaceae and Apodanthaceae. With the exception of Santalales, older parasite lineages tend to be more specialized with respect to trophic level and have lower species diversity. We thus propose the “temporal specialization hypothesis” (TSH) implementing multiple independent specialization processes over time during parasitic angiosperm evolution.
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Naumann, Julia, Karsten Salomo, Joshua P. Der, Eric K. Wafula, Jay F. Bolin, Erika Maass, Lena Frenzke, et al. "Single-Copy Nuclear Genes Place Haustorial Hydnoraceae within Piperales and Reveal a Cretaceous Origin of Multiple Parasitic Angiosperm Lineages." Public Library of Science, 2013. https://tud.qucosa.de/id/qucosa%3A27425.
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Extreme haustorial parasites have long captured the interest of naturalists and scientists with their greatly reduced and highly specialized morphology. Along with the reduction or loss of photosynthesis, the plastid genome often decays as photosynthetic genes are released from selective constraint. This makes it challenging to use traditional plastid genes for parasitic plant phylogenetics, and has driven the search for alternative phylogenetic and molecular evolutionary markers. Thus, evolutionary studies, such as molecular clock-based age estimates, are not yet available for all parasitic lineages. In the present study, we extracted 14 nuclear single copy genes (nSCG) from Illumina transcriptome data from one of the “strangest plants in the world”, Hydnora visseri (Hydnoraceae). A ~15,000 character molecular dataset, based on all three genomic compartments, shows the utility of nSCG for reconstructing phylogenetic relationships in parasitic lineages. A relaxed molecular clock approach with the same multi-locus dataset, revealed an ancient age of ~91 MYA for Hydnoraceae. We then estimated the stem ages of all independently originated parasitic angiosperm lineages using a published dataset, which also revealed a Cretaceous origin for Balanophoraceae, Cynomoriaceae and Apodanthaceae. With the exception of Santalales, older parasite lineages tend to be more specialized with respect to trophic level and have lower species diversity. We thus propose the “temporal specialization hypothesis” (TSH) implementing multiple independent specialization processes over time during parasitic angiosperm evolution.
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Nicolas, Antoine. "UNDERSTANDING EVOLUTIONARY RELATIONSHIPS IN THE ANGIOSPERM ORDER APIALES BASED ON ANALYSES OF ORGANELLAR DNA SEQUENCES AND NUCLEAR GENE DUPLICATIONS." VCU Scholars Compass, 2009. http://scholarscompass.vcu.edu/etd/1701.
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I studied evolutionary history in the angiosperm order Apiales, with a special emphasis on interactions between form, time, and space. Four broad categories of problems were addressed: interfamilial relationships in Apiales, the assignment of genera traditionally assigned to the Apiaceae subfamily Hydrocotyloideae, the estimation of divergence times of the major clades, and the reconstruction of the biogeographic history of Apiales. We used molecular markers with different evolutionary properties and rates derived from the plastid (trnD-trnT and rpl16), nuclear (RPB2), and mitochondrial (nad1 intron 2) genomes, from more than 250 species representing all major clades in the order. The nuclear RPB2 region exhibited evidence of at least six duplication events in Apiales and provided a rich source of information for understanding the origins of polyploid lineages, especially in Araliaceae. Sequence comparisons among the copies show that exon regions are highly conserved. All copies appear to be functional but may have undergone subfunctionalization. Phylogenetic analyses of the three genomes suggest that Hydrocotyloideae should be divided into as many as six evolutionary lineages, but that most taxa should be included in subfamilies Azorelloideae and Mackinlayoideae. Relationships among and within the major clades of Azorelloideae need further analyses since many genera appeared non-monophyletic (e.g., Azorella, Schizeilema, and Eremocharis). Mackinlayoideae appeared as the earliest diverging lineage of Apiaceae, but the plastid and nuclear trees were incongruent in the placement of the Platysace clade relative to Mackinlayoideae and the rest of Apiaceae. Among the remaining clades of suborder Apiineae, Myodocapaceae appeared sister to Apiaceae in both plastid and nuclear trees, preceded by the divergence of Araliaceae and then Pittosporaceae. At the base of the gene trees in Apiales, Griseliniaceae and Torricelliaceae formed successive sisters to Apiineae. The placement of Pennantiaceae as sister to the rest of Apiales was confirmed by plastid data, but was not found in the nuclear trees. The order appears to have originated in the Cretaceous, with Apiineae having an age of c. 100 Mya. Australasia appears to be the most likely center of origin for Apiineae and most of its major clades, except Azorelloideae (South America) and Apioideae-Saniculoideae (sub-Saharan Africa).
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Abdullah, Mansour Taleb. "Conserving the biodiversity of Kuwait through DNA barcoding the flora." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28786.
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Biodiversity across the globe is threatened. Rapid surveying and monitoring techniques are required to understand the origin of the threats to biodiversity and to enable conservation actions to be undertaken. Kuwait is an arid desert country with a small flora of only 402 species. This flora is endangered by environmental factors, overgrazing, and human activities. DNA barcoding the flora and using Next Generation Sequencing (NGS) technologies allowed us to identify plants to species level, conduct a molecular taxonomic revision, and distinguish plant diversity found in soil environmental DNA samples. After investigating the discriminatory power of five commonly used DNA markers from plastid (matK, rbcL, trnH-psbA, trnL) and a nuclear genome (ITS2) on four largest genera of the flora using phylogenetics reconstruction tree based methods, two barcoding markers (rbcL and ITS2) were assigned to build a DNA reference library of the flora. Furthermore, the DNA reference library was tested to identify the plant diversity found below-ground level and comparing it with that above-ground, using environmental soil samples collected from both species rich and poor habitats in Kuwait by applying high-throughput sequencing methods. The DNA database provided in this study could be used as a reference library for the identification process and contribute towards the future of molecular taxonomy, biodiversity and ecological research in Kuwait.
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Ruggiero, Maria Valeria. "Spatial genetic structure in the clonal marine angiosperm Cymodocea nodosa : the influence of dispersal potential, mating system and species interactions." Thesis, Open University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409867.
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Currano, Ellen Diane. "Variations in insect herbivory on angiosperm leaves through the late Paleocene and early Eocene in the Bighorn Basin, Wyoming, USA /." View online, 2008. http://etda.libraries.psu.edu/theses/approved/WorldWideFiles/ETD-2863/Thesis_Currano_final.pdf.
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Mues, Andreas Wilhelm [Verfasser]. "Functional Integration of Floral Plant Traits: Shape and Symmetry, Optical Signal, Reward and Reproduction in the Angiosperm Flower / Andreas Wilhelm Mues." Bonn : Universitäts- und Landesbibliothek Bonn, 2020. http://d-nb.info/1218301872/34.
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Cameron, Duncan Drummond. "A role for differential host resistance to the hemiparasitic angiosperm, Rhinanthus minor L. in determining the structure of host plant communities?" Thesis, University of Aberdeen, 2004. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=238495.
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This study describes the effect of the root hemi-parasitic angiosperm Rhinanthus minor on the structure of the communities in which it lives and seeks to elucidate a mechanism through which the parasite acts to effect these changes in the community. Field manipulations reveal that R. minor suppressed the growth of grasses and legumes in a newly sown meadow whilst promoting the forbs within one growing season. In contrast the removal of R. minor from mature meadow plots did not influence their composition. After an additional growing season the parasite did not further influence the composition of the new meadows but removal did begin to benefit the biomass of mature plots. In isolation the parasite caused most damage to grasses whilst leaving legumes and forbs undamaged. Moreover, the parasite performed worst in terms of growth and photosynthesis when attached to the forbs. Consequently the parasite was able to moderate intra-specific competition between grasses and forbs. I thus hypothesised that forbs were able to prevent the parasite form abstracting resources where as grasses could not. Tracer experiments using isotopically e5N) labelled potassium nitrate confirmed this hypothesis showing that more of the resources taken up by the host were stolen by the parasite from grasses than from forbs. There was much variability in the translocation of resources from the legume studied. The reasons underlying the differential uptake of resources were highlighted using histological studies which showed that all of the forbs possessed successful resistance mechanisms to the parasite whilst no successful resistance was observed in the grasses or legumes. Two different resistance mechanisms were observed in the forbs; hypersensitive cell-death at the host-parasite interface and host lignification. I therefore propose that differential host resistance may underlie this parasite's community level effects as forbs possess a resistance capacity that other potential hosts do not.
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Globo, William Vieira. "Primeiro registro de macroflora do Pleistoceno Final nas margens do rio Teles Pires, MT, Brasil." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/174209.
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Este trabalho tem como objetivo realizar o reconhecimento taxonômico de folhas fósseis de angiospermas, as quais foram recuperadas pelo salvamento paleontológico realizado no âmbito do Programa Investigação, Monitoramento e Salvamento do Patrimônio Paleontológico da UHE Teles Pires. Os depósitos fossilíferos, encontrados em amostras de argilitos laminados, situavam-se no atual leito e terraços (diques marginais) do rio Teles Pires, dentro da área destinada ao reservatório. Na base do afloramento fitofossilífero estudado, restos vegetais em clastos de lama retrabalhados apresentaram idade absoluta entre 22.580 e 23.290 anos AP, obtida por método de radiocarbono (14C). Para a presente contribuição, foram selecionados para determinação taxonômica 27 espécimes, preservados na forma de impressões e compressões. Através da análise e descrição da arquitetura foliar dos espécimes foram identificadas uma monocotiledônea e sete eudicotiledôneas (Albizia subdimidiata e Parkia multijuga, da Família Fabaceae; Brosimum cf. gaudichaudii, da Família Moraceae; Theobroma speciosum e Apeiba sp., da Família Malvaceae; Aspidosperma cf. polyneuron, da Família Apocynaceae, e um espécime atribuído à Família Myrtaceae – Tribo Myrtae). A composição florística dos táxons analisados, juntamente com a distribuição geográfica dos seus representantes atuais e seus respectivos hábitos e hábitats, acusou a predominância de elementos florísticos tipicamente da Floresta Amazônica, sob regime de clima úmido. Porém, duas espécies que podem ocorrer em vegetação de savana foram assinaladas (i.é, Aspidosperma cf. polyneuron, Brosimum cf. gaudichaudii).This work aims at the taxonomic recognition of fossil leaves of angiosperms, which were recovered by the paleontological rescue carried out under the Program Research, Monitoring and Salvage of the Paleontological Heritage of the Teles Pires Hydroelectric Power Plant. The fossiliferous deposits, found in samples of laminated argillite, were located in the current bed and terraces (marginal dikes) of the Teles Pires River, inside the area destined to the water reservoir. At the base of the studied phytophossiliferous outcrop, vegetal remains in reworked mud clasts presented absolute age between 22,580 and 23,290 years BP, through the dating obtained by radiocarbon method (14C). For the present contribution, 27 specimens, preserved in the form of impressions and compressions, were selected for taxonomic determination. A monocotyledonous and seven eudycotyledonous (Albizia subdimidiata and Parkia multijuga, of the Family Fabaceae, Brosimum cf. gaudichaudii, of the Family Moraceae, Theobroma speciosum and Apeiba sp., of the Family Malvaceae, Aspidosperma cf. polyneuron, of the Family Apocynaceae, and a specimen attributed to the Family Myrtaceae - Tribe Myrtae) were identified through the analysis and description of the foliar architecture of the specimens. The floristic composition of the analyzed taxa, together with the geographical distribution of their current representatives and their respective habitats and habits, accused the predominance of floristic elements typically found in the Amazon Rainforest, under a humid climate regime. However, two species that may occur in savanna vegetation have been identified (i.e., Aspidosperma cf. polyneuron, Brosimum cf. gaudichaudii).
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Richardson, Aaron Olson. "Horizontal gene transfer in angiosperm mitochondria function, recombination, and origin of foreign sequences in the mitochondrial genomes of the Zingiberaceae and Amborellaceae /." [Bloomington, Ind.] : Indiana University, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3297106.
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Thesis (Ph.D.)--Indiana University, Dept. of Biology, 2007.Title from dissertation home page (viewed Sept. 29, 2008). Source: Dissertation Abstracts International, Volume: 69-02, Section: B, page: 0842. Adviser: Jeffrey D. Palmer.
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Cunniff, Kevin M. "Phenology, sexual reproduction, and the factors affecting sexual reproduction of the marine angiosperm, Thalassia testudinum, in the Florida Keys National Marine Sanctuary (FKNMS)." FIU Digital Commons, 2005. http://digitalcommons.fiu.edu/etd/2691.
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This study investigated phenology and the factors affecting sexual reproduction of Thalassia testudinum in the FKNMS. Flowering was assessed at 30 permanent monitoring sites via direct observation and age reconstruction techniques of seagrass cores in 2002. The mean flowering frequency was 1.49%, was spatially variable, and exhibited sex-specific timing in floral anthesis. Historical flowering reconstruction demonstrated that flowering frequencies are not temporally variable. Floral sex ratios were female-biased, spatially variable, and likely temporally variable. Relative nitrogen availability was most important in influencing flowering and was negatively correlated with flowering. Higher flowering occurred with low N availability and lower flowering occurred with high N availability. A 15 month in situ nutrient addition experiment conducted at 10 sites in the upper Florida Keys, where N + P were added at ecologically significant loading rates, significantly reduced flowering in the N + P treatment plots at all 10 sites.
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Raftoyannis, Yannis. "Comparative study of the patterns of encystment and pathogenicity of zoospores of Phytophthora and Pythium spp. on a range of axenically-grown angiosperm roots." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287382.
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Xing, Qian. "Genetic dissection reveals distinct roles for the transcription factor ZHOUPI in controlling Arabidopsis endosperm cell death and embryonic cuticle development." Thesis, University of Edinburgh, 2012. http://hdl.handle.net/1842/11718.
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Angiosperm seed development requires co-ordinated development of the embryo and a second zygotic tissue, the endosperm. In Arabidopsis thaliana, the endosperm is ephemeral and is largely consumed by the embryo during seed development. In addition to a role in embryo nutrition, it is also likely that the endosperm may play a more direct role in signalling to the embryo to regulate development. Despite their importance for embryo development, these processes are very poorly understood. The ZHOUPI (ZOU) gene provides an important tool to address these problems. Firstly, ZOU likely regulates endosperm breakdown. Whereas wild-type seed have a single layer of endosperm at maturity, zou seed has a large persistent endosperm and a correspondingly small embryo. The small zou embryo does not fill the seed so that the seed shrivels as it desiccates during maturation. Secondly, zou embryos have defects in their cuticle, so that the endosperm adheres to the embryo throughout seed development. After seed germination, zou cotyledons develop holes in their epidermis as they expand, probably due to the defects in the cuticle. ZHOUPI (ZOU) encodes a bHLH transcription factor and is expressed in the embryo surrounding region (ESR) of endosperm but not in the embryo itself. The role of ZOU in cuticle development is partly mediated by the ABNORMAL LEAF SHAPE1 (ALE1) gene. Thus, ale1 mutants also show defects in embryonic cuticle development and ALE1 is specifically expressed in ESR in a ZOU-dependent fashion. It was unclear whether the effects of ZOU upon embryo development are an indirect consequence of the persistent endosperm mechanically impeding embryo expansion, or rather reflect a more direct role of the ESR in signalling to the embryo. The main aims of this thesis were 1) to provide evidence that ZOU regulates endosperm cell death and 2) to test whether ZOU function in controlling endosperm cell death could be separated from that in embryonic epidermal cuticle development. To achieve this goal, 1) TUNEL assays were performed in the seeds to confirm the zou endosperm cell death phenotype, 2) ALE1 expression in the ESR in zou mutants was rescued using the ZOU-independent AtSUC5 promoter to investigate whether one or both of zou phenotypes were complemented, 3) Candidate ZOU target genes were validated and characterized to determine their functions in endosperm cell death and/or embryonic epidermal cuticle development. The TUNEL assays revealed that zou mutants display less DNA fragmentation in the ESR than that of the wild-type, but that zou did not have defects in cell death outside the seeds suggesting ZOU specifically regulated endosperm cell death. The AtSUC5::ALE1 transgene partially rescued zou defects in epidermal cuticle but not in endosperm cell death. This shows that the defects in the zou cuticle are not caused by the defective endosperm, rather zou has distinct, separable functions. Lastly, I characterised several novel ZOU targets and showed that RGP3 may be a direct ZOU target as it is expressed in ESR in ZOU dependent fashion, whereas RGP4 is likely indirect as it is expressed in the testa and up-regulated in zou mutants. In conclusion, ZOU has independent roles in endosperm cell death and embryonic epidermal cuticle development. Because ALE1, which largely mediates the role in cuticle development, is less widely conserved than is ZOU, the role in promoting endosperm cell death may be the ancestral function of ZOU.
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Branco, Diana Santos 1983. "Sinalização por carboidratos em cana-de-açucar e divergencia evolutiva." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/317165.
Full textAbstract:
Orientadores: Michel Georges Albert Vincentz, Juliana de Maria FelixDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo:Além de fonte primária de carbono e energia para os principais tipos celulares, os açúcares produzidos pela fotossíntese adquiriram importantes funções ao longo da evolução das plantas, no controle do crescimento e desenvolvimento, do metabolismo e na resistência a estresses abióticos (osmótico, energético) e bióticos (potógenos). Os açúcares atuam como sinalizadores ativando cascatas de transdução e, desta forma, promovendo mudanças na programação da expressão gênica. Com o objetivo de entendermos como a sinalização por açúcares diversificou-se em angiospermas, iniciamos uma análise comparativa dos perfis de expressão gênica em resposta aos açúcares sacarose e glicose em plântulas da monocotiledônea Saccharum spp e da eudicotiledônea Arabidopsis thaliana. Para tanto, duas abordagens foram utilizadas. O primeiro aspecto do trabalho estabeleceu relações entre elementos de resposta rápida (resposta primária) a açúcar e acúmulo de sacarose em genótipos de cana contrastantes para teor de sacarose. Outra abordagem, mais abrangente, procurou identificar genes diferencialmente expressos em resposta à sacarose. Na primeira parte do trabalho, a análises por qRT-PCR revelaram uma clara relação entre genes envolvidos em acúmulo de sacarose em cana-de-açúcar e sinalização primária por carboidratos. A partir de 34 SAS (Sugarcane Assembled Sequence) testados envolvidos em acúmulo de sacarose em cana, 24 deles também foram responsivos à glicose e/ou sacarose, sendo que 9 deles responderam em um mesmo sentido em genótipos de cana-de-açúcar que acumulam maior quantidade de sacarose (alto Brix). Dos 24 SAS responsivos à sacarose e/ou glicose, apenas 6 deles apresentaram genes ortólogos em Arabidopsis thaliana cuja regulação por estes açúcares ocorreu de maneira similar. Dentre eles, temos o fator de transcrição IAA16, que se mostrou reprimido por sacarose e glicose, constituindo um possível gene de interação entre sinalização por açúcares e auxina. Duas SNFs quinases parálogas de cana-de-açúcar tem como ortólogo um único gene de Arabidopsis thaliana. Os três genes foram reprimidos por sacarose e glicose, sendo outra parte conservada, na via de sinalização a açúcares entre as duas espécies. Outro gene de particular interesse corresponde a uma deidrina, reprimida por sacarose e glicose em cana, assim como seu ortólogo em Arabidopsis e genótipos alto Brix, sugerindo importante papel deste gene em processos relacionados a sinalização/acúmulo de sacarose. Na segunda parte do trabalho, utilizando-se a técnica de microarranjos de cDNA a partir do chip SUCAST, encontramos 55 genes diferencialmente expressos em resposta à sacarose. Destes, apenas 3 apresentaram genes ortólogos de Arabidopsis regulados por açúcar num mesmo sentido que em cana, correspondentes a duas proteínas quinases e a um gene pseudo-response-regulator. Este estudo preliminar identificou genes conservados da sinalização por açúcares em angiospermas que representam possíveis nós importantes das redes de controle relacionadas a carboidratos. O estabelecimento de um possível envolvimento de alguns destes genes no controle da capacidade de acumular mais sacarose no colmo da cana, abriu novas perspectivas na análise molecular desta importante característica. Estudos mais abrangentes são necessários para melhorar os conhecimentos sobre o grau de diversificação da sinalização por açúcares em angiospermas e os valores adaptativos associados.
Abstract: Besides act as carbon primary source in the major types of cells, sugars produced by photosynthesis acquired important functions in the course of plant's evolution like controlling growth, development, and metabolism and acting in resistance to abiotic and biotic stresses like osmotic, energetic and response to pathogens. Sugars can be signals that active signal transduction pathways to change genes expression programs. In order to access the diversification of sugar pathway signaling in angiosperms we conduct comparative analysis of the gene expression in response to sucrose and glucose in seedlings of the monocot Saccharum sp. and the eudicot Arabidopsis thaliana. We also aimed to access the possible correlation between genes related to sucrose storage in sugar-cane and genes related to primary sugar responses. Another aim was to identify deferentially expressed genes in sucrose response. A clearly relation between genes related to sucrose storage in sugar-cane and quickly primary response to sugars was obtained by qRT-PCR analysis. We tested 34 SAS (Sugar Assembled Sequence) related to sucrose storage in sugar-cane and we found that 24 of them were responsive to glucose and/or sucrose. Nine genes showed the same expression pattern (induction or repression) in response to sugar as seen in high Brix genotypes. Six, of this 24 genes, have Arabidopsis orthologues regulated in the same direction (induced or repressed). One is an IAA16 transcription factor that is repressed by both, glucose and sucrose, and may play a role in an integrative pathway of sugar and auxin responses. We also find two SNFs kinases (paralogues) related to a single Arabidopsis ortholog showing the repression response. Another interesting gene is a dehydrin that was repressed in response to sucrose and glucose in sugar-cane and Arabidopsis (its ortholog) and in the high Brix sugar-cane genotypes. It suggests an important role for this dehydrin in processes related to sucrose signaling and storage. In the second part of this work, the sugar-cane cDNA microarray chip, called SUCAST, allow us to identify 55 deferentially expressed in response to sucrose. Only three of these genes have orthologues regulated in same way in sugar-cane and Arabidopsis. These genes correspond to two protein-kinase and a pseudo-response regulator. This preliminary approach leads us to identify conserved genes in sugar signaling among angiosperms that possibly represents important nodes in the regulatory networks in response to sugars. Establishing the involvement of some of these genes in the ability of sucrose storage in sugar-cane's culm will lead us to new perspectives in the molecular basis of this characteristic. More specific works are also needed to improve the knowledge about the real degree of evolutive diversification in sugar signaling among angiosperms and associated genetic fitness.
Mestrado
Genetica Vegetal e Melhoramento
Mestre em Genética e Biologia Molecular