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1v. (various paging) : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Sc.)--University of Adelaide, Dept. of Botany, 1978

Graduation date: 1993

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This investigation was designed to determine the effects of environmental elements on the color retention and durability of 65/35 polyester/cotton blend fabric with disperse-reactive dyes and durable press and soil release finishes. The colors of fabric used were intense shades of red, blue, and yellow. Data were collected from unlaundered and from laundered and line-dried fabric samples. Fabric samples were exposed to zero, approximately 1,349, 2,836, 5,551, and 11,627 langley units of solar radiation and to varying amounts of other environmental elements. The tear strength, weight, and color retention of the fabric were studied. As the number of langley units to which the fabric samples were exposed increased, the color retention of the fabric tendd to decrease. The combined effects of the other environmental elements appeared to be secondary to solar radiation in reducing the color retention of the fabric. There was also a decrease in the tear strength of the fabric. This appeared to be due to the combined effects of all of the environmental elements on the fabric. The tear strength, weight, and color retention were lower in the laundered fabric samples than in the unlaundered fabric samples.

The aim of this study was to test the hypothesis that ryegrass and clover, when grown under optimal conditions in mixed stands, interact in response to available light energy. with other resources non-limiting, pasture yield is determined by the efficiency with which solar radiation is intercepted by canopies and converted into dry matter. The clover-ryegrass interaction under varying light regimes, as experienced in the canopies of these pastures, was studied by investigating the growth and production of ryegrass and clover in relation to light harvesting abilities and photosynthetic utilization of intercepted light. Pasture canopy structure and growth were studied under a four-weekly clipping treatment. The interception of photon flux density (PFD) in the pasture canopy was monitored diurnally and seasonally in mixed and mono cultures. Light use efficiency (C02 fixed/ unit absorbed PFD) as well as photochemical efficiency of photosystem II (Fv/Fm) were studied by monitoring CO2 assimilation rates and chlorophyll fluorescence respectively. The results obtained from this study indicated that interaction did occur between ryegrass and clover, cultivated in mixed pastures. The mixture was capable of more efficient light interception than the mono cultures, which resulted in higher productivity. Light interception abilities, as manifested in canopy architecture, and not physiological utilization of light energy, were found to govern the interaction between the two pasture components. / Thesis (M.Sc.)-University of Natal, Durban, 1993.