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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

The organisation of clonal growth in a stoloniferous plant, Ranunculus repens L

Oatway, David Edward January 2000 (has links)
No description available.
2

Vegetative Propagation and Topophytic Responses of Selected Baldcypress Clones

King, Andrew Richard 2010 August 1900 (has links)
Baldcypress, Taxodium distichum (L.) Rich., var. distichum is a highly adaptable tree of significant ecological importance in the Southeastern U.S. Including Taxodium distichum var. imbricarium (Pondcypress) and Taxodium distichum var. mexicanum (Montezuma cypress), the native range is extended into south Texas and Mexico. Previously, baldcypress selections were made for drought, foliar salt exposure and high pH soil tolerance. Experiments were conducted beginning in May, 2008 to determine commercial viability of vegetative propagation by shoot tip cuttings of these selections, to identify treatment combinations that led to optimal rooted cutting quantity and quality, and to determine whether baldcypress cuttings displayed a topophytic effect and if so, if there was a correlation between branch angle on the ortet and topophysis exhibited by ramets during nursery production. The propagation studies revealed that rooted cutting quantity and quality were optimal when softwood cuttings were taken from south Texas and/or Mexican provenances and treated with either 7,500 or 15,000 mg·L-1 K-IBA (potassium salts of indole-3-butyric acid). A gradient was observed with cuttings from more southern and western provenances typically exhibiting greater rooted cutting quantity and quality than cuttings from more eastern and northern provenances. A tradeoff between greater rooting percentages in a substrate with greater aeration (100 percent perlite) versus greater root quality (root numbers, length, or mass) in a substrate with a higher water-holding capacity (100 percent peat moss) was also displayed. Additional basal wounding proved to be detrimental to both rooted cutting quantity and quality. A significant (P </= 0.05) topophytic effect was observed among genotypes for the divergence of central leaders from a vertical orientation during nursery production, but the branch angle of the cutting on the ortet was not a good predictor of this divergence on the ramet.
3

Ecological Causes and Evolutionary Consequences of Fitness Variation in Lobelia cardinalis

Bartkowska, Magdalena 27 May 2013 (has links)
Understanding the functional relationship between characters and components of fitness is a central goal of evolutionary biology. The studies in this thesis examined the ecological causes and evolutionary consequences underlying differences in fitness among individuals of Lobelia cardinalis. Flowering plants experience selection from many sources, which may enhance or oppose selection by pollinators. In the second chapter of this thesis, the role of pollinators and herbivores in shaping selection on floral characters was investigated. Floral traits experienced pollinator-mediated selection and weak selection by weevil larvae and slugs. Because pollinators also forage according to local density of flowers, in the fourth chapter I explored how local density of individual plants and flowers influences fitness of individual plants. Plants at dense sites produced more seeds, consistent with pollinator preference for denser patches. Individual female-phase flowers produced more seeds as the density of surrounding male-phase flowers increased and female-phase flowers decreased. This study highlights how plant phenotype and local density influence pollination and subsequent plant fitness. In L. cardinalis rosette formation (a life-history character) partly shapes the distribution of plants, and may influence plant survival and fitness. In the fifth chapter, I explored how variation in allocation to clonal reproduction among plants (ramets) and genets influenced survival and fitness. Plants that produced more and larger rosettes realized higher survival independent of the phenotype of the parental. Plants that produced one rosette in 2009 produced more seeds in 2010 than plants that produced more than one rosette. This pattern was reversed in the following time period; plants that produced more rosettes in 2010 produced more seeds in 2011. The relative importance of pollinators versus other selective agents in shaping floral traits, as well as the intensity of competition among individual plants and flowers likely depend on the extent to which reproduction is pollen limited. In the third chapter, I explored how pollen limitation affected selection on floral traits via female fitness and found a weak relationship. Although this seems to contradict intuition, several reasons may limit the influence of pollen limitation on selection.
4

Clonal population structure and genetic variation of ramet-production traits in a clonal plant, Cardamine leucantha / クローナル植物コンロンソウにおける集団クローン構造とラメット生産形質の遺伝的変異

Tsujimoto, Michiaki 23 March 2020 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第22286号 / 理博第4600号 / 新制||理||1660(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 工藤 洋, 教授 田村 実, 准教授 高山 浩司 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
5

クローンを形成する雌雄異株低木ヒメモチにおけるクローン多様性と遺伝的変異

鳥丸, 猛, TORIMARU, Takeshi 12 1900 (has links)
農林水産研究情報センターで作成したPDFファイルを使用している。
6

Developmental Contributions to Variation in Aspen Clones and the Influence of Pre-Fire Succession Status on Aspen Regeneration Success

Smith, Eric A. 09 July 2010 (has links) (PDF)
This thesis includes two studies: The first examined developmental changes that take place in the physiology of aspen (Populus tremuloides Michx.) and to characterize developmental influences on patterns of phenotypic trait variation among different aged ramets within the aspen clones. We surveyed eight clones, each with 8 distinct age classes ranging from 1 to 170 yrs in age. Using regression analysis we examined the relationships between ramet age and expression of functional phenotypes. Eight of the phenotypic traits demonstrated a non-linear relationship in which large changes in phenotype occurred in the early stages of ramet development and stabilized thereafter. Water and nutrient concentration, leaf gas exchange and phenolic glycosides tended to decrease from early to late development, while sucrose and condensed tannin concentrations and water use efficiency increased with ramet age. We hypothesize that ontogenetically derived phenotypic variation leads to fitness differentials among different aged ramets, which may have important implications for clone fitness. Age-related increases in phenotypic diversity may partially underlie aspen's ability as a species to tolerate the large environmental gradients that span its broad geographical range. Fire is an essential component of many forest ecosystems and fire exclusion policies and other anthropogenic factors have significantly altered disturbance regimes, which has lead to increased aspen succession to conifers. The second study examined how post-fire aspen regeneration success is influenced by increasing conifer abundance under longer fire return intervals. 66 sites were selected from the Sanford prescribed fire complex located in the Dixie National Forest. Slope, aspect, sucker regeneration heights, soil samples, and post and prefire stand densities were measured. Results from this study demonstrated that pre-disturbance conifer abundance and aspen densities are good predictors of aspen sucker regeneration success. Results also found that although conifer densities don't change across aspects, aspen densities are different on north facing slopes. We hypothesize the high levels of aspen regeneration came from a large disturbance size which overwhelmed the high levels of herbivores.
7

Recognition Denied: An Examination of UK and US Foreign Policy towards the Republic of Croatia

Ljubic, Maria Christina 02 May 2013 (has links)
This thesis examines the development of decision making taken by two countries, the United Kingdom and the United States, in response to Croatia’s declaration of independence from Yugoslavia. The focus is on the recognition process and the reasoning and rationale used by the government officials and diplomats of the United Kingdom and United States to arrive at their policy decisions and opinions. The concentration is mainly on events from the early 1990s until mid 1992. Topics explored include matters such the politics behind non-recognition, democratic social norms, respect for human rights and Western national interests. The thesis first hypothesizes, then analyses, which International Relations theory, that is, realism or constructivism, possesses the best capacity explain why these nations initially withheld their recognition of Croatia’s independence before moving to accept the Republic of Croatia as an independent state. The role of the International Relations theories is to offer an interpretation and understanding of these events and decisions. Subsequently, they are judged on their ability to do so. The thesis finds that via the insight of scholars, analysts and theoretical perspectives that both the John Major government of the UK and the George H.W. Bush Administration of the United States behaved mostly according to realist principles, with some instances of constructivist manner. / Graduate / 0615 / 1616 / 0335 / cljubic9@gmail.com

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