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The chlorophyll degradation pathway is central to a number of plant processes including senescence and fruit ripening. However, the regulation of the chlorophyll degradation pathway enzymes is not well understood. The aim of this thesis was to elucidate the genetic mechanisms that control changes in pigment composition leading to fruit flesh yellowing in kiwifruit. Actinidia deliciosa and A. chinensis fruit, which are green and yellow, respectively, provide an opportunity to study the regulation of chlorophyll levels. The expression of genes that code for enzymes of the chlorophyll and cytokinin metabolic pathways was measured using qRT-PCR. Candidates for chlorophyll degradation regulatory points were then characterised for functionality by transient transformation in N. benthamiana. The endogenous cytokinin levels were measured in kiwifruit and transient activation assays were carried out with the promoters of key candidate genes. Overall, expression of the chlorophyll degradation genes was elevated in yellow fruit and expression of biosynthetic genes was higher in green fruit. The chlorophyll degradation-associated protein, STAY-GREEN2 (SGR2), was more highly expressed in yellow fruit, and transient over-expression of SGR was sufficient to drive chlorophyll degradation. Expression of isopentenyl transferase (IPT), the rate-limiting step for cytokinin biosynthesis, showed an increase towards maturity in green fruit, but not in yellow fruit. However, both fruit had similar high levels of cytokinin nucleotides and free bases. A gene coding for O-glucosylation was also highly expressed in green fruit. Green fruit contained higher levels of cytokinin O-glucosides and ribosides towards maturity, suggesting differences in cytokinin signalling, which could lead to regulation of chlorophyll levels via activation of the SGR promoter by transcription factors. It is likely that the chlorophyll degradation pathway and cytokinin metabolism are linked. The differential expression of cytokinin response regulators could lead to differential regulation of cytokinin levels in the fruit of the two species, and possibly differential regulation of the chlorophyll degradation pathway. Progress towards elucidation of the control of chlorophyll levels provides knowledge of this key process in kiwifruit and potentially gene-based markers for breeding new kiwifruit cultivars.

The thesis examines changes in hunter-gatherer land-use along lower Cypress Creek, atributary of the Green River located in west-central Kentucky. Presented, are the results of the firstthree years of site survey and museum work conducted by the Cypress Creek Archaeological Project.Analysis of site location and hafted bifaces suggests that, throughout the Holocene, increasingemphasis was placed on certain locations and areas of the landscape. Comparison of the CypressCreek study area with other areas of Archaic research indicate that land-use was highly variable inboth space and time across the North American midcontinent.

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Grazing and no-till management in organic systems have been recently proposed tools to improve nutrient cycling and sustainability. From 2008 to 2012 a series of field experiments were established to identify green manure species and green manure management options to maximize N benefit to following cash crops and explore the opportunities to reduce tillage during the green manure phase of an organic rotation. A total of four green manure systems (double-cropped green manures, relay-cropped green manures, full season green manures, and catch crops after grazed full season green manures), three green manure management options (soil incorporation, grazing and no-till), and 10 green manure species, as well as, three green manure mixtures were tested. Double-cropped pea (Pisum sativum cv. 40-10) and relay-cropped red clover (Trifolium pratense) produced around 900 kg ha-1 and 2000 kg ha-1 of biomass respectively. The greatest biomass producing full season green manures were hairy vetch (Vicia villosa L.), pea/oat (Avena sativa cv. Leggett/Pisum sativum cv. 40-10) and sweet clover (Mellilotus officinalis cv. Norgold). Pea/oat and hairy vetch were the most weed competitive species and on average contained less than 15% weed biomass. Among all the systems and managements tested, nitrogen availability was greatest when full season green manures were grazed. On average grazing increased soil NO3-N by 25% compared to soil incorporation using tillage. Among grazed species, pea/oat mix and hairy vetch green manures resulted in the greatest amount of soil available NO3-N. Catch crops after grazing green manures, regardless of the species, significantly reduced N leaching risk compared to no catch crop treatment, but also reduced wheat productivity the following year. Catch crop biomass productivity and N uptake, soil NO3-N, and wheat productivity were similar in direct seeded and conventionally seeded plots. Grazing may be an effective tool in reducing tillage in organic agriculture because of its ability to accelerate the N mineralization from catch crop biomass. This study was the first study to use grazing as a management tool for green manures in organic systems. Results provide strong evidence that green manures, especially when grazed, can be effective nitrogen suppliers in organic grain based rotations.

Green Procurement is defined as taking into account environmental criteria for goods and services to be purchased in order to ensure that the related environmental impact is minimized (Incite Sustainability, 2008: vii).An inherent feature of green procurement is the integration of environmental considerations into purchasing policies, programmes and actions (Stigson & Russell, 1998:9). The European Commission states that green public procurement should ideally cover areas such as the purchase of energy-efficient computers and buildings, office equipment made out of environmentally sustainable timber, recyclable paper, environmentally-friendly public transport, organic food in the cafeteria, electricity stemming from renewable energy sources and air conditioning systems complying with environmental solutions(European Commission, 2004:5). The International Council for Local Environmental Initiatives (ICLEI) recommends the inclusion of the construction of new buildings, restoration and renovation as well as the purchase of building material as one of the areas that have to be addressed when developing green procurement policies. The City of Tshwane Municipality (CoT) intends to move towards a green procurement practice. The City plans to attain the latter without deviating from the intentions and parameters of the South African Government’s procurement legislation and further more within the limits of its current budget constraints. The intention of the study was to investigate the feasibility of a green procurement practice in the CoT and to give special attention to low cost housing. The results of the study suggest that it is feasible to implement the practice. The City of Tshwane was found to have relevant and progressive policies in place and what was found lacking was the application and integration of the policies into existing programmes. Green procurement barriers that the CoT will have to overcome were identified as awareness, motivation, economic, legal, institutional, information and technical barriers. The study concludes with recommendations to the CoT with regard to potential opportunities the City can take advantage of when implementing a green procurement practice. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2010.

Green Procurement is defined as taking into account environmental criteria for goods and services to be purchased in order to ensure that the related environmental impact is minimized (Incite Sustainability, 2008: vii).An inherent feature of green procurement is the integration of environmental considerations into purchasing policies, programmes and actions (Stigson & Russell, 1998:9). The European Commission states that green public procurement should ideally cover areas such as the purchase of energy-efficient computers and buildings, office equipment made out of environmentally sustainable timber, recyclable paper, environmentally-friendly public transport, organic food in the cafeteria, electricity stemming from renewable energy sources and air conditioning systems complying with environmental solutions(European Commission, 2004:5). The International Council for Local Environmental Initiatives (ICLEI) recommends the inclusion of the construction of new buildings, restoration and renovation as well as the purchase of building material as one of the areas that have to be addressed when developing green procurement policies. The City of Tshwane Municipality (CoT) intends to move towards a green procurement practice. The City plans to attain the latter without deviating from the intentions and parameters of the South African Government’s procurement legislation and further more within the limits of its current budget constraints. The intention of the study was to investigate the feasibility of a green procurement practice in the CoT and to give special attention to low cost housing. The results of the study suggest that it is feasible to implement the practice. The City of Tshwane was found to have relevant and progressive policies in place and what was found lacking was the application and integration of the policies into existing programmes. Green procurement barriers that the CoT will have to overcome were identified as awareness, motivation, economic, legal, institutional, information and technical barriers. The study concludes with recommendations to the CoT with regard to potential opportunities the City can take advantage of when implementing a green procurement practice. / Thesis (M. Environmental Management)--North-West University, Potchefstroom Campus, 2010.

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No description available.

No description available.