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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 20 of 81 for “"angiosperms"”.
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Reversal of Polarity In Some Woody Dicotyledonous Angiosperms
… hypothesis as regards some woody dicotyledonous Angiosperms – special emphasis being given to Salix Babylonica (the weeping willow).</p>
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The Pollination Ecology of Four Species of Local Vernal Herbaceous Angiosperms
… ecology of four populations of vernal herbaceous angiosperms representing four locally common species of plants in the Central New York State area were studied. Three study sites were selected and research was conducted in the field by personal observation and accepted experimental methods. Four …
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Rethinking phylogenetics using Caryophyllales (angiosperms), matK gene and trnK intron as experimental platform
… phylogeny for the plant order Caryophyllales (angiosperms). We also investigate the utility of trnK intron in phylogeny reconstruction at relativley deep evolutionary history (the caryophyllid order) by comparing it with rapidly evolving matK. We show that trnK intron is comparable to matK in …
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Induction of growth and pigmentation changes by hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in angiosperms
Eighteen angiospermous species of plants were assayed for tolerance of Hexahydro- 1,3,5-trinitro-1,3,5-triazine (RDX). Plants were grown in RDX soil treatments of 100, 500, and 1000 mg per kg for 60 days. Tolerance of RDX, expressed as a mean percentage of control dry mass, was greatest for …
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Investigations Into the Effects of Light and Darkness on Chlorophyll Biosynthesis in Angiosperms (Monovinyl, Divinyl Protochlorophyllide)
Three separate studies were undertaken.
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Activation of seed-specific genes in leaves and roots of the desiccation tolerant plant, Xerophyta humilis
… desiccation tolerance is common in seeds of most angiosperms it is rare in their vegetative tissues. Xerophyta humilis (Bak.) Dur and Schintz belongs to a small group of resurrection angiosperms and it possesses the ability to withstand extreme desiccation of greater than 90% in both its seeds and …
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The influence of the evolution of anatomical characters on leaf hydraulic capacity
… water flow. T he general difference was between angiosperms and other taxa, with angiosperms showing higher values for anatomical and functional characters. Under dynamic light (step-change or diurnal change), angiosperms had more coordination among gas exchange parameters with leaf hydraulic …
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Regulation of desiccation tolerance in Xerophyta seedlings and leaves
A small, diverse group of angiosperms known as resurrection plants display vegetative desiccation tolerance and can survive loss of up to 95% of cellular water, a feat only seen in the seeds and pollen of other angiosperms. Xerophyta humilis is a resurrection plant native to Southern Africa that …
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The economic challenge of leaf gas exchange
… 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 adaptive …
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The economic challenge of leaf gas exchange
… 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 adaptive …
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Molecular evolution of the RNA polymerase genes and the phylogeny of seed plants
… project focuses on major 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 …
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The largest subunit of RNA polymerase II (rpb1) as a phylogenetic marker of seed plant species
The phylogeny of land plants, especially angiosperms, has been perplexing scientists for more than 125 years. The aim of this study was to help elucidate unanswered phylogenetic issues using rpb1 genes from twenty-six land plant species (8 gymnosperm species, 17 angiosperm species and Psilotum, a …
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Glucuronic Acid Patterning on Xylan in Arabidopsis thaliana
… cell wall polysaccharide after cellulose. For angiosperms, the xylan backbone consists of repeating xylosyl residues and is decorated along its length by acetate and glucuronic acid (GlcA). It is likely that the position of these decorations, created by Trichome-Birefringence-Like (TBL) and …
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The Evolutionary Dynamics of Conflicts of Interest in Plant Mating Systems
The diversity of flowering plants -angiosperms- on planet Earth is nearly matched by the diversity of mating systems and floral traits they exhibit. Since Darwin evolutionary biologists have been fascinated by this diversity and worked to explain and understand it. In this thesis I focus on aspects …
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Adaptation to the host-plant, and the evolution of host specialization, in 'cycad weevils' (Coleoptera: Brentidae)
… era (ca. 200 MYA) before the rise of the angiosperms and which are now represented by 11 genera with relict distributions in the tropics and sub-tropics. The primary aim of this research was to determine the possible causes of narrow host specialization in Antliarhinus zamiae (Thunberg) …
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Biogeographical And Evolutionary Processes Influencing The Assembly Of Deciduous Forest Plant Communities
… fertile soils in the early diversification of angiosperms in Temperate Deciduous Forests. These patterns suggest that calcium-rich soils may be an ecological ‘zone of origin’ for angiosperms and highlight the potential for longterm evolutionary processes to influence species diversity in …
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Quantitative palynological analyses of Albian-Cenomanian (Lower to Upper Cretaceous) strata in the Sverdrup Basin: Insights into paleoecology, paleoclimatology and palynostratigraphy
… a delay in the dispersal and diversification of angiosperms into the Sverdrup Basin relative to more southern locations. This latitudinal diachroneity may potentially be due to paleogeographic barriers, such as, the Arctic Ocean, the extent of the Western Interior Seaway, or due to limited insect …
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Characterization of polyphenols in leaves of four desiccation tolerant plant families
… as light screens. In this study polyphenols in angiosperms found in southern Africa and called resurrection (desiccation tolerant) plants were studied. These plants are Myrothamnus flabellifolius, Xerophyta viscosa, Xerophyta humilis, Xerophyta schlecterii, Xerophyta villosa. Craterostigma …
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The Role of Carotenoid Cleavage Dioxygenase 4 in Flower Color of the Allopolyploid Brassica napus
… color phenotype of carotenoid-synthesizing angiosperms. Here, we investigate the genetic and epigenetic role of <em>CCD4 </em>orthologs and their role in flower color phenotype of <em>B. napus</em>.</p>
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