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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A taxonomic revision of the low larkspurs of the Pacific Northwest.

Sutherland, David Michael, January 1967 (has links)
Thesis (Ph. D.)--University of Washington. / Bibliography: l. [121]-122.
2

Cytogenetics of Delphinium (Ranunculaceae) Species Native to Oregon

Turner, Jill Yeatman 02 November 1992 (has links)
Evidence of hybridization, known to occur in the genus Delphinium (Ranunculaceae ), has recently been discovered among certain Delphinium species native to Oregon. This issue was investigated by cytogenetic analysis of four native species of Oregon, D. trolliifolium, D. menziesii, D. pavonaceum and D.leucophaeum, and an unidentified purple delphinium, which is possibly a hybrid. Although many species in this genus are karyotypically similar, any variations found among the karyotypes of these Oregon species might be used to identify parental chromosomes in the purple delphinium (proposed hybrid). Meiotic analysis was used to detect structurally heterozygous homologues that are not observable in somatic cells. Reproductive success, an extension of meiosis, was also investigated. In lieu of the endangered status of two of these Oregon species, attempts were made to develop a system for obtaining dividing cells for cytogenetic study that has negligible impact on plant populations. Apical meristems of seed radicles from the Oregon species and the proposed hybrid were stained with orcein. The metaphase chromosomes were photographed and measured, and chromosome arm ratios and relative lengths calculated. Analyses of variance and multiple comparison tests were run to determine if any significant differences in chromosome measurement exist among these Oregon delphiniums. Satellites and other morphological features were noted. Anther contents were also stained with orcein and microsporogenesis examined. Pollen viability and percent seed germination was determined for each of the species and the proposed hybrid. Callus and organized tissue that developed in vitro were stained with orcein and the mitotic cells examined. The unhanded karyotypes of the Oregon species and the proposed hybrid are similar in number, size and shape; major structural differences between species, if present, are not observable at this level of chromosome resolution. No markers for the identification of parental chromosomes in the proposed hybrid are available with this staining technique. However, statistical analysis of mean chromosome arm ratio and length indicates that D. menziesii, D. pavonaceum and D.leucophaeum are more closely related to one another than they are to D. trolliifolium and the proposed hybrid, and vice versa. D. trolliifolium is therefore a candidate parent species of the proposed hybrid whereas the other three species are likely not candidates. Karyotypes of these Oregon species are different from those of some species from outside Oregon. This is evidence of chromosome evolution in this genus. The absence of structural heterozygosity in meiotic metaphase I of the proposed hybrid suggests that (1) if it is a hybrid, the genomes of the parent species are structurally similar or (2), recurrent backcrossing with the same parent species may have gradually eliminated the chromosomes of the other parent from the hybrid line. High numbers of viable pollen and germinated seeds were found in all the species and the proposed hybrid, evidence that reproductive capacity is not adversely affected by its potentially hybrid condition. Mitosis in tissue culture varies, depending, to a large degree, on cell type. Organized tissues such as roots are sources of more stable karyotypes than calluses, which tend to be mixoploid. The development of plant structures in culture indicates a potential for in vitro plant regeneration.
3

Isolation and structure elucidation of new compounds from Cornus Controversa and Delphinium Chrysotrichum

Unknown Date (has links)
The aim of this dissertation was to explore structurally unique secondary metabolites from herb medicinal plants Cornus controversa and Delphinium chrysotrichum. The introduction in the first chapter provides a detailed review about the research progress of chemical constitutents of the genus Cornus. In addition, its pharmacological activities were also summarized in this chapter to provide a framework for understanding the roles of medicinal herbs belong to genus Cornus as anti-diabetes therapeutics and to deliver useful information for further research. In chapter two, seven new compounds, including one iridoid glucoside, cornoside A (59), five iridoid aglycones, cornolactones A – E (60 – 64) and one indenone glucoside, cornoside B (65), together with 10 known compounds have been isolated from the leaves of Cornus controversa. The structures of these compounds were established by interpretation of spectroscopic data. Cornolactone A (61) is the first natural cis-fused tricyclic dilactone iridoid containing both a five- and six-membered lactone ring. Cornoside B (65) is the first alkaloid isolated from the genus Cornus bearing an indole-3-lactic acid-11--D-glucopyranoside skeleton. In chapter three, we described the structure elucidation of three new diterpenoid alkaloids delphatisine D (77), chrysotrichumines A (78) and B (79), as well as 11 known compounds from the whole plants of Delphinium chrysotrichum. Delphatisine D (77) is a rare atisine-type alkaloid from genus Delphinium and is the C-15 epimer of spiramine C which bears an internal carbinolamine ether linkage (NCOC) between C-7 and C-20. Chrysotrichumine A (78) is a rare natural C19-diterpenoid alkaloid possessing a nitrone group between C-17 and C-19. In addition, their cytotoxic activity against human breast cancer cell lines of MCF-7 and MDA-MB-231 were also reported. In chapter four, the detailed extraction and isolation procedures of the new compounds, cornosides A and B, cornolactones A – E, delphatisine D, chrysotrichumine A and B, as well as of all the known compounds were described. In addition, the experimental procedures for the determination of PPARγ and LXR agonistic activities and the MTT cytotoxicity assay were listed in this chapter. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection
4

Phytochemistry of norditerpenoid alkaloids from Aconitum and Delphinium

Ahmed, Mai January 2016 (has links)
Aconitum and Delphinium genera are important rich sources of toxic C19-diterpenoid alkaloids. The alkaloidal content of A. napellus and D. elatum seeds have been investigated in detail. After maceration, crude alkaloidal extracts were obtained and then purified by repeated column chromatography (over silica and alumina gels) to sample homogeneity yielding five known C19-diterpenoid alkaloids from A. napellus, aconitine, neoline, 14-O-acetyltalatisamine, 14-O-benzoylaconine, and taurenine, and two others from D. elatum, delpheline (also including its X-ray single crystal analysis) and methyllycaconitine (MLA). These examples showed that mass spectrometry hyphenated with HPLC or other chromatography can be used as a tool for rapid alkaloid content screening of different extracts. NMR spectroscopic (using a variety of techniques and nuclei) data are presented in support of the first report of iminodelsemine A/B as an imino-alkaloid artefact from D. elatum. A detailed chromatographic study across different pH ranges, and over different solid supports, of aconitine and its main degradation product, 14-O-benzoyl-8-O-methylaconine, together with its semi-synthesis and that of its deuterated analogue are reported within studies to minimize artefact formation during the storage or extraction of A. napellus norditerpenoid alkaloids. Likewise, from D. elatum seeds, as a model source of Delphinium alkaloids, we compared the alkaloid yield using different extraction techniques and conventional chromatographic separations. The structures were confirmed by NMR spectroscopy and mass spectrometry. An NMR spectroscopic approach for the pKa determination of some C19-diterpenoid alkaloids has been developed. A modified calculation method for fatty acid composition quantification has also been developed using 1H-NMR spectroscopic methods.
5

Spatial Variation in Bidirectional Pollinator-Mediated Interactions Between Two Co-Flowering Species in Serpentine Plant Communities

Stanley, Amber, Martel, Carlos G., Arceo-Gómez, Gerardo 01 December 2021 (has links)
Pollinator-mediated competition and facilitation are two important mechanisms mediating co-flowering community assembly. Experimental studies, however, have mostly focused on evaluating outcomes for a single interacting partner at a single location. Studies that evaluate spatial variation in the bidirectional effects between co-flowering species are necessary if we aim to advance our understanding of the processes that mediate species coexistence in diverse co-flowering communities. Here, we examine geographic variation (i.e. at landscape level) in bidirectional pollinator-mediated effects between co-flowering and We evaluated effects on pollen transfer dynamics (conspecific and heterospecific pollen deposition) and plant reproductive success. We found evidence of asymmetrical effects (one species is disrupted and the other one is facilitated) but the effects were highly dependent on geographical location. Furthermore, effects on pollen transfer dynamics did not always translate to effects on overall plant reproductive success (i.e. pollen tube growth) highlighting the importance of evaluating effects at multiple stages of the pollination process. Overall, our results provide evidence of a spatial mosaic of pollinator-mediated interactions between co-flowering species and suggest that community assembly processes could result from competition and facilitation acting simultaneously. Our study highlights the importance of experimental studies that evaluate the prevalence of competitive and facilitative interactions in the field, and that expand across a wide geographical context, in order to more fully understand the mechanisms that shape plant communities in nature.
6

Understanding Factors Influencing Seed Germination of Seven Wildflowers in Sub-Alpine Ecosystems

Brown, Alyssa Joy 09 December 2021 (has links)
This thesis explores the seed germination of seven wildflowers native to sub-alpine ecosystems. Wildflowers are an essential functional group in native plant ecosystems. Also known as forbs, these plants offer a myriad of benefits in addition to being aesthetically pleasing. They provide habitats for anthropods and small mammals, support native pollinator populations, and grow well with other plant functional groups (especially perennial grasses and shrubs). Healthy plant communities make use of the limited resources in our native ecosystems, competing with invasive species that can otherwise dominate the landscape. Germination involves the transition from seed to an actively growing plant. Following germination, the seedling relies on stored energy reserves until it becomes as an autotrophic organism. Because germination is irreversible, it is the most vulnerable period of the plant lifecycle. Seeds of sub-alpine plants typically have complex dormancy-breaking requirements before growth begins. Therefore, understanding factors that influence the germination is essential to understanding propagation for horticultural use as well as timing of seedings for ecological restoration. The first chapter investigates the germination behavior of two co-occurring Asteraceae species across an elevation gradient. Mules ear (Wyethia amplexicaulis) and arrowleaf balsamroot (Balsamorhiza sagittata) seeds were collected at low, mid, and high elevation locations then subjected to a number of cold stratification treatment lengths (4-20 weeks) Both showed variance in germination behavior between elevation collection locations, with higher locations exhibiting a longer stratification requirement. The second study was developed to determine methods for breaking dormancy in five wildflower species for which existing literature is nonexistent or lacking. Delphinium nuttalianum (low larkspur), Delphinium exaltatum (tall larkspur), Frasera speciosa (green gentian), Polemonium foliosissimum var. alpinum (Jacob's ladder), and Mimulus grandifloras (monkey flower) were selected for this study because they all have the potential for use in horticulture and restoration ecology applications. Three species (low larkspur, tall larkspur, and green gentian) required long-term cold stratification to break dormancy. Jacob's ladder required physical scarification to break dormancy, and monkey flower required the combination of constant temperature with light exposure to germinate. These findings indicate that 1) six of seven species should be autumn-planted, and that propagation for horticulture use for five of the species is a lengthy process involving several months; 2) propagation of monkey flower seeds include strict temperature and light requirements; and 3) while seeds collected from different locations have the same type of dormancy-breaking requirements, variation in the degree of seed dormancy has ecological relevance.
7

Effects of Road Dust on the Pollination and Reproduction of Wildflowers

Waser, Nickolas M., Price, Mary V., Casco, Genesis, Diaz, Maria, Morales, Asia Liza, Solverson, Jennie 02 1900 (has links)
Premise of research. Dust particles and pollen grains are similar in size. Dust deposition might therefore influence the pollination and reproduction of flowering plants. Little is known about such effects, however, despite more general interest in ecological effects of dust. Methodology. We used observational and experimental methods to explore whether dust generated by traffic on unpaved roads affects the amounts of pollen received and numbers of seeds produced by four species of native wildflowers in the western United States. Pivotal results. Flowers of Nuttall's larkspur (Delphinium nuttallianum), scarlet gilia (Ipomopsis aggregata), Lewis flax (Linumlewisii), and sulphur paintbrush (Castilleja sulphurea) growing 1-2mfrom a road received substantially more dust and less pollen than those growing 40-50 m away. We observed the same pattern when we transplanted individuals of the first two species into pots and placed pots near to compared with far from a road. Experimental "hand dusting" of scarlet gilia and Lewis flax plants also reduced stigma pollen loads to a degree that resembled the average effect of road proximity for those species. On the other hand, numbers of seeds per flower ("seed set") did not vary consistently for any species as a function of road proximity or hand-dusting treatment. Conclusions. Several mechanisms might contribute to the different effects of dust on pollen loads and seed set. Wediscuss four possible mechanisms, which we refer to as pollen excess, pollen quality, resource limitation, and compensatory herbivory. These mechanisms suggest avenues for further study of dust, pollination, and plant reproduction with this and other systems.
8

Dispersion of the Host Specific Phytophagous Insects of Duncecap Larkspur (Delphinium Occidentale) in the Wasatch Mountains of Utah

Bayn, Robert L, Jr. 01 May 1975 (has links)
Populations of Delphinium occidentale (Ranunculaceae)were monitored over two summers for the presence and dispersion of various life stages of several host specific phytophagous insects. Observations were made at several sites in the Wasatch National Forest east of Logan, Utah. Two species of larkspur aphid (Aphis rociadae and Kakimia wahinkae) were encountered. Although dispersal of alate individuals resulted in widespread infestation of the host plant population, aphids occurred initially on the same one or few plants at each site both springs. Little coexistence of the two species of aphid on the same plant was observed, perhaps because they partitioned the host plant resource according to light intensity under the incomplete aspen canopy. Several species of lepidopteran larvae, of uncertain host specificity, were observed. Two species (Autographa californica and pyrrhia expremins: Noctuidae) are known from cultivated host plants. Eggs of an unidentified geometrid (Lepidoptera) were located on the host plants in large numbers and their dispersion was analysed. The eggs were distributed nonrandomly over the host plant population, but attempts to further characterize the pattern were fruitless. Parasitism of the eggs by an unidentified hymenopteran was observed. Mortality of all larvae was high. Successful migration of larvae was not observed. Mature larvae were not sufficiently abundant to permit statistical study of pattern. Mature fruits were examined at the end of the growing season for larkspur maggots (Hylemya laxifrons). Maggots were found in 85 percent of the inflorescences sampled. Pteromalids (Hymenoptera) were also found in an apparently parasitic relationship with the maggots in the fruits. Maggots were not found in the surviving fruits of inflorescences infested with either species of aphid. Suggestions are given for future work.

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