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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

An improved tissue culture and transformation system for switchgrass (Panicum virgatum L.)

Burris, Jason Neil 01 December 2010 (has links)
Switchgrass (Panicum virgatum), a summer perennial grass native to North America, is currently being explored for its potential use in the production of biofuels. With these interests, genetic manipulation of switchgrass to produce plants that are easier to digest, have an increased resistance to diseases and stresses, and maintain viability longer in the field are required. Therefore, it was necessary to develop a reliable and efficient tissue culture system for the transformation of switchgrass. Current switchgrass tissue culture requires months for regeneration of transformants with relatively poor transformation efficiencies and are limited to derivatives of a single variety, Alamo. We have developed a tissue culture system, utilizing a novel media, LP9, which has demonstrated decreased time to the production of whole transgenic plants and with an increased efficiency. LP9 is not an MSO-based tissue culture system. It is comprised of both N6 macroelements and B5 microelements with the auxin, 2,4-D and does not include any cytokinin. After just 1 month on LP9 media, callus can be selected and used for Agrobacterium tumefaciens-mediated transformation or particle bombardment, and plants can be regenerated within 3 weeks of callus initiation. Our system is unique to previously explored MSO-based systems in that it is optimized for the production of type II callus, which has been shown to produce higher transformation efficiencies in other monocots. We have increased the transformation efficiency of switchgrass from to up to 4% to 34% efficiency by selecting for this type of callus.
2

Trade-off analysis of forest ecosystem services – A modelling approach

Pang, Xi January 2017 (has links)
Forest is a resource that is increasingly utilized for multiple purposes. The balance between energy demands and the long-term capacity of ecosystems to support biodiversity and other ecosystem services is crucial. The aim of this project was to increase the knowledge on and to develop methods and tools for trade-offs and synergies analysis among forest ecosystem services based on different forest management policies. Paper I provides an overview of existing models for integrated energy-environment assessment. A literature review was conducted on assessment models and their ability to integrate energy with environmental aspects. Missing environmental aspects concern land use, landscapes and biodiversity. In Paper II a modelling framework was set up to link a landscape simulator with a habitat network model for integrated assessment of bioenergy feedstock and biodiversity related impacts in Kronoberg County. In Paper III we continued with the same management scenarios, while the analysis was expanded to five ecosystem services by developing the Landscape simulation and Ecological Assessment (LEcA) tool: industrial wood, bioenergy, forest carbon stock, recreation areas and habitat networks. In Paper IV we present two heuristic methods for spatial optimization – simulated annealing (SA) and genetic algorithm (GA) – to find optimal solutions for allocating harvest activities, in order to minimize the impacts on habitat networks. In Paper V, as response to the findings in Paper I, we linked the energy model MESSAGE with our LEcA tool for forest bioenergy demand assessment while applying environmental and transport restrictions, in a study of Lithuania. We found trade-offs between industrial wood production and bioenergy on one side, and recreation values, biodiversity, and to some extent carbon storage on the other side. The LEcA tool integrated forest simulation and management with assessment of ecosystem services, which is promising for integrated sustainability assessment of forest management policies. / <p>QC 20171023</p>
3

Sustainable Bioenergy Feedstock Production Using Long-Term (1999-2014) Conservation Reserve Program Land

Raut, Yogendra Y. 08 August 2017 (has links)
No description available.

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