Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 19 of 19 for “"Gymnosperms"”.
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Molecular evolution of the RNA polymerase genes and the phylogeny of seed plants
… groups of seed plants (angiosperms, and four gymnosperms groups: conifers, cycads, Ginkgo and Gnetales). These organisms diverged roughly three hundred million years ago and evolved independently since then. Therefore, morphological characters have limited power in resolving their phylogeny. …
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Using microarrays to elucidate the genetic basis of wood density in sitka spruce and poplar
… from two<br/>contrasting species, Sitka spruce (gymnosperms) and poplar (angiosperms).<br/>Genes up-regulated in high-density Sitka spruce and poplar samples had<br/>functions in cell formation and expansion, with down-regulated genes having<br/>functions in lignin biosynthesis, stress-response …
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The largest subunit of RNA polymerase II (rpb1) as a phylogenetic marker of seed plant species
… with that of protein trees. Both angiosperms and gymnosperms were monophyletic. Amborella was found at the base of the angiosperm tree, followed by Nymphae, then Illicium. These data rejected the anthophyte hypothesis, weakly supported the gnepine hypothesis, but did not resolve the …
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A new member of the zygopteridales from the lower Upper Devonian (Frasnian) of Ellesmere, N.W.T., Arctic Canada
… be careful in attributing such foliage to early gymnosperms.
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Paleoenvironmental reconstruction based on palynological and palynofacies analyses of the Aptian-Albian succession in the Sergipe Basin, northeastern Brazil
… dominated by the pollen group, in particular gymnosperms, which is by far the most abundant group in the two wells studied. In well GTP-17-SE the second most abundant group is the spores. Well GTP-24-SE is characterized by high abundance of marine. One zone and two sub-zones and one zone of …
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Palynology and Age of the Alvord Creek Formation, Steens Mountain, Southeastern Oregon
… are encountered in the palynoflora including the gymnosperms Tsuga, ?Taxodium, Podocarpus, and Ephedra and the angiosperms Quercus, Ulmus, Corylus, Juglans, Fraxinus, and Nyssa. Pollen assigned to the undivided Taxaceae-Cupressaceae-Taxodiaceae group, Quercus and Abies dominate the assemblage; …
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Identification of Fossil Wood from the Specimen Creek Area of the Gallatin Petrified Forest, Yellowstone National Park, Montana
… identified as follows: 3 families, 9 genera, in Gymnosperms; 13 families, 15 genera in Angiosperms.</p> <p>PINACEAE: Keteleeria*, Larix*, Pinus, Tsuga*</p> <p>PODOCARPACEAE: Podocarpus</p> <p>TAXODIACEAE: Glyptostrobus*, Sequoia, Taxodium*</p> <p>*ACERACEAE: Acer*</p> <p>BETULACEAE: Alunus, …
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Molecular interactions of plant cell wall polymers
… and hemicelluloses occur in Angiosperms and Gymnosperms and that these interactions may play roles in the maintenance of plant material properties, such as the recalcitrance to enzymatic digestion.
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Impacts of Elevated Carbon Dioxide and Tropospheric Ozone on the Growth and Productivity of Trees
… and 17% by 2100. The study also revealed that gymnosperms were affected significantly less than angiosperms, suggesting that [O3] also has the potential to alter the composition of mixed forests. Root to shoot ratio was also decreased suggesting that beside decreased biomass, forests might …
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Glucuronic Acid Patterning on Xylan in Arabidopsis thaliana
… GUX2 from angiosperms, specifically AtGUX2, and gymnosperms, focusing on PtGUX2, and identified an SRF amino acid motif in PtGUX2, absent in angiosperms, crucial for creating consecutive GlcA decorations on the xylan backbone. Taken together with results from mutagenesis of the predicted active …
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The economic challenge of leaf gas exchange
… assessed across 15 species, encompassing ferns, gymnosperms and angiosperms. The aim was to determine whether angiosperms possessed innovations that could provide them with an adaptive advantage over earlier-diverging lineages in a dynamic light environment, or whether observed relations followed …
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The economic challenge of leaf gas exchange
… assessed across 15 species, encompassing ferns, gymnosperms and angiosperms. The aim was to determine whether angiosperms possessed innovations that could provide them with an adaptive advantage over earlier-diverging lineages in a dynamic light environment, or whether observed relations followed …
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Systematics and evolutionary biology of the Weevils associated with cycads in Australia
Cycads are subtropical and tropical palm-like gymnosperms, commonly known as "living fossils" as they arose in the late Paleozoic and were much more diverse and dominant during the Mesozoic. Modern cycads underwent a recent global diversification in Miocene (ca. 11-20 mya). Even though cycads were …
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Systematics and evolutionary biology of the Weevils associated with cycads in Australia
Cycads are subtropical and tropical palm-like gymnosperms, commonly known as "living fossils" as they arose in the late Paleozoic and were much more diverse and dominant during the Mesozoic. Modern cycads underwent a recent global diversification in Miocene (ca. 11-20 mya). Even though cycads were …
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Systematics and Ecology of Truffles (Tuber)
… Pacific Northwest and associated primarily with Gymnosperms. Chapter 4 is a meta-analysis of all known Tuber ITS rDNA sequences (e.g. from Genbank and generated from herbarium collections) available at the time. These were placed within the Tuber phylogeny to assess species diversity, …
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Molecular studies on the taxonomy, host-associations and viruses of the Diplodia-like anamorphs of the Botryosphaeriaceae
… and “Botryosphaeria” quercuum. Infection of gymnosperms most likely occurred more recently, only in specific groups (Diplodia and Lasiodiplodia) via host shifts. Three distinct viruses have now been characterized from isolates of D. pinea sensu lato. Two of these were previously characterized …
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Carbon and Water Relations in Pinus Taeda: Bridging the Gap across Plant Physiology, Genomics, and Global Climate Change
… tree species including both angiosperms and gymnosperms. The relationship between vulnerability to cavitation (ψ<sub>50</sub>) and hydraulic conductivity within specific organs (i.e. stems and roots) was not significant when considering the phylogenetic association between species. However, …