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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.
61

Reproductive response to elevated CO2 : the roles of vegetative carbon storage, nitrogen and seed traits

Jablonski, Leanne M. January 1997 (has links)
This study focused on the reproductive response to elevated CO2 of plants possessing below-ground storage. I tested the hypotheses that under elevated CO2: (1) Plants with greater non-foliar storage capacity win show more reproductive response and (2) The altered foliar physiology of carbon (C) and nitrogen (N) use will cause increases in seed number and quality. Carbon dioxide treatments of High (650 muL L-1) and Ambient (360 muL L-1) were used in a controlled environment, simulated growing season, and in a natural pasture community. Hypothesis 1 was tested experimentally using four Raphanus varieties that differed in hypocotyl and leaf sizes. N fertilization and harvest times were used to obtain a range of root:shoot ratios. Enhancements in vegetative leaf area rather than the hypocotyl predicted reproductive responsiveness to CO 2. However, after three years of CO2 exposure in the pasture, hypocotyl-storing Taraxacum officinale responded strongly in vegetative biomass which correlated with inflorescence size and number. Fitness was enhanced four-fold, while the leaf-storing Plantago major produced more ramets and had only a two-fold fitness increase. Hypothesis 2 was tested by examining the C and N physiology underlying the vegetative organs and seeds of the pasture plants. Under elevated CO2, photosynthesis increased two-fold and senescence was delayed. Total plant C:N ratio did not differ, suggesting N acquisition increased. N similarly limited seed number in all cases suggesting an unchanged Physiology of N use in reproduction. While morphology constrained total biomass response, provisioning to seeds increased as shown by higher seed mass and number and decreased variability in number and mass. In all cases, leaf mass increase under high CO2 corresponded with fitness increase. Phenology constrained response to CO 2 as there was no plasticity in flowering day in Raphanus and Plantago, while there were flowering delays but greater seed maturation rate in Tar
62

Structural analysis of airborne flux traces and their link to remote sensing of vegetation and surface temperature

Caramori, Paulo Henrique January 1992 (has links)
This thesis examines the link between airborne flux estimates of CO$ sb2$, sensible heat, and water vapor, and surface parameters retrieved by remote sensing. Chapter 1 analyses the relationship between surface temperature and vegetation indices, obtained from the Advanced Very High Resolution Radiometer on board of NOAA-9 and -10 satellites, and fluxes of sensible heat, latent heat, and CO$ sb2$, estimated from aircraft. Linear relationships between CO$ sb2$ and the Normalized Difference Vegetation Index (NDVI) or the Simple Ratio vegetation index (SR) are found on a daily basis, but a highly nonlinear relationship appears for the seasonal variation. Latent Heat fluxes showed the poorest correlations with surface parameters. A seasonal linear relationship appeared between sensible heat and NDVI. Local extreme flux values due to the intermittency of boundary layer dynamics largely contribute to lower the correlations; such variations are the reason for the difficulties in relating fluxes obtained from single overpasses and over short distances to fixed points at the surface. This problem is further examined in Chapter 2, in which conditional sampling of airborne flux estimates is used to characterize the turbulent structures that are carrying flux, and their link to the surface. The analysis confirms that few extreme events may carry a significant fraction of the flux. Missing or hitting one of these structures may translate into very large oscillations on the flux estimate that are often not directly coupled to surface characteristics. A much clearer surface 'signature' emerges when measurements are taken within the surface layer, since the reorganization of turbulent structures that takes place with increasing height will result in a merging of the signature that came from different sources at the surface. This helps to explain some of the poor correlations obtained in Chapter 1 and reinforces the need for a better understanding of the distributions of these tu
63

Investigation of the long term physiological response of Huon pine (Lagarostrobos franklinii) to changes in atmospheric CO2 and climate using stable isotopes

Pepper, David A. January 1999 (has links)
Thesis (Ph. D.)--University of Sydney, 2000. / Title from title screen (viewed February 12, 2009). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Biological Sciences, Faculty of Science. Degree awarded 2000; thesis submitted 1999. The 2 in the title is in subscript. Includes bibliographical references. Also available in print form.
64

Coalfire related CO₂ emissions and remote sensing = Aan steenkoolbranden gerelateerde CO₂ uitstoot en aardobservatie /

Gangopadhyay, Prasun Kumar, January 1900 (has links)
Thesis (doctoral)--Universiteit Utrecht, 2008. / Includes bibliographical references (p. 127-140).
65

Carbon dynamics following landscape fire : influence of burn severity, climate, and stand history in the Metolius Watershed, Oregon /

Meigs, Garrett W. January 1900 (has links)
Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 106-118). Also available on the World Wide Web.
66

Non-anthropogenic sources of carbon dioxide in the Glowworm Cave, Waitomo

Miedema, Natalie Margaret. January 2009 (has links)
Thesis (M.Sc. Earth and Ocean Sciences and Chemistry)--University of Waikato, 2009. / Title from PDF cover (viewed October 2, 2009). Includes bibliographical references (p. 161-170)
67

The carbonate system in seawater : laboratory and field studies /

Murphy, Paulette P. January 1996 (has links)
Thesis (Ph. D.)--University of Washington, 1996. / Vita. Includes bibliographical references (p. [228]-243).
68

Carbon and Water Relations in Pinus Taeda Bridging the Gap across Plant Physiology, Genomics, and Global Climate Change

Moura, Catarina Fernandes, January 2008 (has links)
Thesis (Ph. D.)--Duke University, 2008.
69

Development of a System for Real-Time Measurements of Metabolite Transport in Plants Using Short-Lived Positron-Emitting Radiotracers

Kiser, Matthew R., January 2008 (has links)
Thesis (Ph. D.)--Duke University, 2008.
70

Interannual variability of atmospheric carbon dioxide flux in the equatorial Pacific Ocean

Verschell, Mark Alan, January 1996 (has links)
Thesis (Ph. D.)--Florida State University, 1996. / Typescript. Includes bibliographical references.

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