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 20 of 70 for “"flowering plants"”.
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Evolution of Reproductive Characteristics in Some Flowering Plants
Made available in DSpace on 2014-12-14T16:11:12Z (GMT). No. of bitstreams: 1 7715012.pdf: 5666194 bytes, checksum: bb791cffb921472cd32da54503628d37 (MD5) Previous issue date: 1977
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Interactions between ants and diaspores of flowering plants (myrmecochory) in Sicily (Southern Italy): an important ecosystem function of the Mediterranean basin
Almeno 11.500 specie esistenti (e forse il doppio) di piante a fiore della divisione Angiospermae, stringono rapporti di mutualismo (obbligato o facoltativo) in habitat diversi su tutti i continenti ad eccezione dell Antartide, attraverso le loro diaspore sessuali (semi o frutti + appendici esterne …
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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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A Comparative Study of the Reproductive Biology of Sympatric Morning Glories (<em>Ipomoea</em>-convolvulaceae)
<p>Despite the astounding diversity of flowering plants and of mobile organisms that serve as pollinators, sympatric co-flowering plants can potentially share pollinators with each other. This places two selection pressures on plants. First, plants compete for pollinators to visit their flowers and …
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Cytogenetic Studies in the Genus Cymbidium
… of the most highly specialized groups of green plants. Botanically the flowers are of more than passing interest for they deviate so distinctly from the norm of the Monocots. They are the possessors of a number of unique structures that are found in no other family of flowering plants.</p>
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Moth pollination, low seed set, and vestigialization of attractive floral traits in Abronia umbellata (Nyctaginaceae)
Flowering plants display remarkable phenotypic diversity, especially in reproductive structures, much of which is thought to be associated with pollination by animals. Pollination syndromes are collections of floral traits (e.g. flower colour, shape, odour) that are associated with a plant …
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Extending Plant-Plant Facilitation Theory to Pollinators: Do Desert Shrubs Act as Magnets?
The magnet hypothesis proposes that flowering plants that attract pollinators can increase the relative pollination rates of neighbouring plants. The principal objective of this thesis was to 1) systematically review the theoretical and methodological trends in pollinator facilitation and magnet …
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The Bees of Two Sites in the Big Thicket National Preserve, Texas, with a Consideration of the Effects of a Rare Flooding Event
… ecosystems due to their coevolution with flowering plants. This study catalogued the bee fauna of two sandyland sites in the Big Thicket National Preserve and assessed whether a community was impacted by a historic hurricane-induced flooding event. It was hypothesized that a change in …
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Assessment of the microbiome associated with endangered orchids
… family) is perhaps the most speciose group of flowering plants with approximately 25,000 described species and many thousands of hybrids. While certain mycorrhizal fungi are required for orchids to germinate, these mycorrhizae form just part of a microbial community that interacts with the …
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THE RNA-BINDING PROTEIN LRP1 MEDIATES FLOWERING TIME IN ARABIDOPSIS
In flowering plants such as <i>Arabidopsis thaliana</i>, floral transition is tightly regulated by a complex network of genetic pathways. FLOWERING LOCUS C (FLC), a MADS-box transcription factor, is a strong repressor of this flowering process, intricately controlled by several genetic pathways, …
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Natural Selection on S-Linked Genes in Turnera (Passifloracease)
… that determine the expression of distyly in flowering plants. Several approaches were adopted to explore the signatures of selection on S-linked genes in distylous Turnera. While dN/dS-based results revealed pervasive purifying selection at the S-locus in Turnera, average nucleotide diversity …
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Determining the Fate of Hybridized Genomes in the Allopolyploid Brassica napus
… the evolution and speciation of the majority of flowering plants. Allopolyploid forms through interspecific hybridization and whole genome duplication. While allopolyploids may display increased vigor relative to their progenitors, they can also face challenges to fertility following …
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Pollen digestion in flower-feeding Scarabaeidae : protea beetles (Cetoniini) and monkey beetles (Hopliini)
Beetles pollinate over 80% of all flowering plants and feed on the two most common floral rewards, nectar and pollen. Pollen is nutritionally very valuable, being a rich protein and carbohydrate source. However, the hard and highly resistant outer wall (exine) of the grain is an obstacle that …
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On the molecular pathways supporting the development of structurally coloured cuticle in Hibiscus trionum
… appeared between 250 and 125 million years ago, flowering plants are the most diverse group of plants with about 78% of plant species. The staggering diversity of flowering plants is often correlated with their capacity of adaptation to the diversity of niche space offered by numerous different …
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Resolving Gnetum Evolutionary History
<em>Gnetum</em> are non-flowering seed plants of the tropics, indigenous to South America, Africa, and Asia. This group of about 40 species is fascinating to botanists because it shares distinctive morphological characteristics with flowering plants, such as broad leaves, woody stems, and …
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Investigating the role of the cytoskeleton and signalling in the self-incompatibility response of Papaver rhoeas
Many flowering plants are hermaphrodite, which poses the problem of self-fertilisation and the subsequent loss of genetic fitness in the offspring. To prevent this, plants have developed a genetically controlled mechanism called self-incompatibility (SI) which allows self (incompatible) pollen to …
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A bright, sweet evolution: a molecular genetic analysis of Calvin cycle gene expression response to light and sugar in the liverwort marchantia polymorpha, and insights into Calvin cycle promoter motif enrichment in land plants
Higher plants are frequently used as model organisms in Calvin Benson Bassham cycle (CBB) research given their ease of use in the laboratory. The expression of CBB genes in higher plants is well known to be regulated by light, sugar and plant development, yet no focus has been given to lower plant …
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Diversity and virulence of the genus Cronobacter revealed by multilocus sequence typing (MLST) and comparative genomic analysis
… years ago, during the period of evolution of flowering plants. The MLSA was also used in a polyphasic study for the formal recognition of two new species – C. universalis and C. condimenti. The MLST scheme also revealed the high level of clonality in the species C. sakazakii and C. …
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Multiple dimensions of floral rewards drive pollinator behavior and pollen movement
Animal pollinated plants produce a diversity of rewards to attract pollinating insects. Most commonly these are nutritional rewards; either pollen (primarily protein and lipids) and/or nectar (primarily carbohydrates) in varying combinations and qualities. This reward strategy varies inter- and …
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Molecular Characterization of Stress Response in Western Honey Bee (Apis mellifera)
… are incredibly important for the reproduction of flowering plants and the sustainability of agricultural ecosystems. However, they face various stressors such as pesticides, pathogens, habitat loss, and climate change. Extensive research has been conducted to understand how bees respond to these …
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