Magister Scientiae (Biodiversity and Conservation Biology) / South Africa is recognised worldwide for its rich diversity of plants, many of which have been used in ethno-medicine. However, the use of wetland plant species in ethno-medicine required further investigations. This research is aimed at investigating three wetland medicinal, plant species, Centella asiatica, Cyperus longus and Typha capensis based on their geographical, seasonal, mineral nutrient (Fe, Mn, Ca, Mg, K and Na) and secondary metabolite characteristics. Samples of each species were collected from Grabouw, Kelderhoff, Kenilworth, Pringle Bay, University of the Western Cape (UWC) and Worcester within the Western Cape Province of South Africa. Specimen and soil collections were carried out during autumn, spring, summer and winter of 2014. Both plant and soil samples were acid digested and mineral nutrient concentrations in the samples were analysed using an atomic absorption spectrometer (AAS). Secondary metabolites were determined using analytical TLC on normal phase Merck-Silva gel coated aluminium plates as well as by using HPLC separation from crude extracts of C. asiatica, C. longus and T. capensis using LC-MS hardware from Agilent. The elemental analysis of soil samples showed that Ca, K, Mg, Mn and Zn concentrations were predominantly low. Soil mineral concentrations increased progressively from inland (Worcester) towards the coastland in the south (Pringle Bay). Calcium and sodium concentrations, in particular, were higher in soil samples obtained from Grabouw (inland south) and decreased northward towards Worcester. Comparatively, plant mineral concentrations were generally higher than soil concentrations. The high concentration of some of these essential elements, in selected plants is an indication that these plant species could be a good source of essential elements. High concentrations of phytochemicals were found in Centella asiatica during winter, while Cyperus longus and Typha capensis exhibited high concentrations during autumn indicating variation in respect of season. Consequently, harvesting of the studied plants should be done at the season with a relatively high phytochemical concentration. Studies are needed to investigate the extent of pesticide or herbicide contamination in wetland plants to protect the health of users. The LC-MS analyses of the three study species showed that seasonal variation affects metabolite constituents and moreover that these metabolite constituents differ from one locality to another. The seasonal variation of the elements in the studied medicinal plants justified the importance of harvesting seasons in the optimal utilization of the studied plants for medicinal purpose. s, for C. asiatica, anti-bacterial treatments for C. longus and fertility enhancement and birth control for T. capensis.

São realizados estudos termodinâmicos de nitretos, carbonetos e carbonitretos dos microelementos V, Nb, Al e Ti, utilizando bancos de dados computacionais do programa FactSage, com finalidade de verificar seus potenciais como inibidores do crescimento do grão na faixa de temperatura do processo de forjamento a quente dos aços. Um procedimento para verificação da solubilidade dos compostos dos microelementos por meio do FactSage foi desenvolvido e foram estudadas situações mais complexas e menos abordadas na literatura, tais como o efeito combinado de dois microelementos no aço e o estudo do comportamento dos carbonitretos em altas temperaturas com variantes do porcentual de carbono e nitrogênio. Os estudos demonstraram que os nitretos com presença de titânio possuem elevada estabilidade em altas temperaturas e, por isso, são potencialmente muito efetivos no controle do crescimento do grão. Alguns carbonetos com presença de nióbio apresentam também uma boa estabilidade em altas temperaturas, assim como os carbonitretos desses dois elementos. Foi verificada uma boa correlação dos produtos de solubilidade obtidos tanto por métodos experimentais como por cálculos termodinâmicos apresentados pela literatura, bem como a valiosa contribuição do software para estudos de precipitação e dissolução de carbonetos, nitretos e carbonitretos na austenita, permitindo auxiliar na seleção de aços e/ou modificação da composição de aços convencionais por meio da adição de microelementos juntamente com uma escolha apropriada de porcentuais de nitrogênio e/ou carbono, quando se busca controlar o crescimento do grão em altas temperaturas. Os resultados obtidos podem auxiliar de forma indireta nos estudos de eliminação de tratamentos térmicos convencionais, seja pelo uso de aços microligados com resfriamento controlado, seja pelo uso de aços convencionais de baixa liga temperados logo após forjamento, permitindo, assim, uma redução dos custos globais das peças. Além dessas considerações, os resultados apresentados e a técnica desenvolvida podem também ser úteis em outras áreas em que seja importante o controle do crescimento do grão, tais como laminação a quente e cementação em alta temperatura. / Thermodynamics studies of nitrides, carbides and carbonitrides of the micro elements V, Nb, Al and Ti were performed using the FactSage program databases, in order to verify their potential for grain growth inhibition in a range of temperatures of hot forged steels. A procedure to verify the solubility of compounds of the micro elements was developed by means of FactSage, and it was studied complex states less discussed in literature, such as the combined effect of two micro elements in steel and the behavior of carbonitrides at high temperatures, varying carbon and nitrogen contents. The studies demonstrate that the nitrides with Titanium have high stability in austenite at elevated temperatures: therefore they are potentially highly effective in grain size control. Carbides with Niobium also present effective stability at high temperatures, as well as the carbonitrides of these two elements. A good correlation was verified between the solubility product obtained either by experimental methods, or by thermodynamics calculation presented by literature. Also, a valuable contribution is made by the software in the studies of precipitation and dissolution of nitrides, carbides and carbonitrides in austenite; thus aiding the selection of steels, and/or modification of the chemical composition of standardized steels, by means of adding micro elements; and providing a suitable choice of carbon and nitrogen content when one seeks to control the grain growth at elevated temperatures. Such results can help indirectly in the studies eliminating conventional heat treatment methods, by using micro alloyed steels with controlled cooling and low alloy steels quenched after forging, with overall reducing costs. Besides these considerations, the results presented and the developed procedure can be useful in other areas where grain growth is an important factor, such as in hot rolling and carburizing at high temperature.

São realizados estudos termodinâmicos de nitretos, carbonetos e carbonitretos dos microelementos V, Nb, Al e Ti, utilizando bancos de dados computacionais do programa FactSage, com finalidade de verificar seus potenciais como inibidores do crescimento do grão na faixa de temperatura do processo de forjamento a quente dos aços. Um procedimento para verificação da solubilidade dos compostos dos microelementos por meio do FactSage foi desenvolvido e foram estudadas situações mais complexas e menos abordadas na literatura, tais como o efeito combinado de dois microelementos no aço e o estudo do comportamento dos carbonitretos em altas temperaturas com variantes do porcentual de carbono e nitrogênio. Os estudos demonstraram que os nitretos com presença de titânio possuem elevada estabilidade em altas temperaturas e, por isso, são potencialmente muito efetivos no controle do crescimento do grão. Alguns carbonetos com presença de nióbio apresentam também uma boa estabilidade em altas temperaturas, assim como os carbonitretos desses dois elementos. Foi verificada uma boa correlação dos produtos de solubilidade obtidos tanto por métodos experimentais como por cálculos termodinâmicos apresentados pela literatura, bem como a valiosa contribuição do software para estudos de precipitação e dissolução de carbonetos, nitretos e carbonitretos na austenita, permitindo auxiliar na seleção de aços e/ou modificação da composição de aços convencionais por meio da adição de microelementos juntamente com uma escolha apropriada de porcentuais de nitrogênio e/ou carbono, quando se busca controlar o crescimento do grão em altas temperaturas. Os resultados obtidos podem auxiliar de forma indireta nos estudos de eliminação de tratamentos térmicos convencionais, seja pelo uso de aços microligados com resfriamento controlado, seja pelo uso de aços convencionais de baixa liga temperados logo após forjamento, permitindo, assim, uma redução dos custos globais das peças. Além dessas considerações, os resultados apresentados e a técnica desenvolvida podem também ser úteis em outras áreas em que seja importante o controle do crescimento do grão, tais como laminação a quente e cementação em alta temperatura. / Thermodynamics studies of nitrides, carbides and carbonitrides of the micro elements V, Nb, Al and Ti were performed using the FactSage program databases, in order to verify their potential for grain growth inhibition in a range of temperatures of hot forged steels. A procedure to verify the solubility of compounds of the micro elements was developed by means of FactSage, and it was studied complex states less discussed in literature, such as the combined effect of two micro elements in steel and the behavior of carbonitrides at high temperatures, varying carbon and nitrogen contents. The studies demonstrate that the nitrides with Titanium have high stability in austenite at elevated temperatures: therefore they are potentially highly effective in grain size control. Carbides with Niobium also present effective stability at high temperatures, as well as the carbonitrides of these two elements. A good correlation was verified between the solubility product obtained either by experimental methods, or by thermodynamics calculation presented by literature. Also, a valuable contribution is made by the software in the studies of precipitation and dissolution of nitrides, carbides and carbonitrides in austenite; thus aiding the selection of steels, and/or modification of the chemical composition of standardized steels, by means of adding micro elements; and providing a suitable choice of carbon and nitrogen content when one seeks to control the grain growth at elevated temperatures. Such results can help indirectly in the studies eliminating conventional heat treatment methods, by using micro alloyed steels with controlled cooling and low alloy steels quenched after forging, with overall reducing costs. Besides these considerations, the results presented and the developed procedure can be useful in other areas where grain growth is an important factor, such as in hot rolling and carburizing at high temperature.

São realizados estudos termodinâmicos de nitretos, carbonetos e carbonitretos dos microelementos V, Nb, Al e Ti, utilizando bancos de dados computacionais do programa FactSage, com finalidade de verificar seus potenciais como inibidores do crescimento do grão na faixa de temperatura do processo de forjamento a quente dos aços. Um procedimento para verificação da solubilidade dos compostos dos microelementos por meio do FactSage foi desenvolvido e foram estudadas situações mais complexas e menos abordadas na literatura, tais como o efeito combinado de dois microelementos no aço e o estudo do comportamento dos carbonitretos em altas temperaturas com variantes do porcentual de carbono e nitrogênio. Os estudos demonstraram que os nitretos com presença de titânio possuem elevada estabilidade em altas temperaturas e, por isso, são potencialmente muito efetivos no controle do crescimento do grão. Alguns carbonetos com presença de nióbio apresentam também uma boa estabilidade em altas temperaturas, assim como os carbonitretos desses dois elementos. Foi verificada uma boa correlação dos produtos de solubilidade obtidos tanto por métodos experimentais como por cálculos termodinâmicos apresentados pela literatura, bem como a valiosa contribuição do software para estudos de precipitação e dissolução de carbonetos, nitretos e carbonitretos na austenita, permitindo auxiliar na seleção de aços e/ou modificação da composição de aços convencionais por meio da adição de microelementos juntamente com uma escolha apropriada de porcentuais de nitrogênio e/ou carbono, quando se busca controlar o crescimento do grão em altas temperaturas. Os resultados obtidos podem auxiliar de forma indireta nos estudos de eliminação de tratamentos térmicos convencionais, seja pelo uso de aços microligados com resfriamento controlado, seja pelo uso de aços convencionais de baixa liga temperados logo após forjamento, permitindo, assim, uma redução dos custos globais das peças. Além dessas considerações, os resultados apresentados e a técnica desenvolvida podem também ser úteis em outras áreas em que seja importante o controle do crescimento do grão, tais como laminação a quente e cementação em alta temperatura. / Thermodynamics studies of nitrides, carbides and carbonitrides of the micro elements V, Nb, Al and Ti were performed using the FactSage program databases, in order to verify their potential for grain growth inhibition in a range of temperatures of hot forged steels. A procedure to verify the solubility of compounds of the micro elements was developed by means of FactSage, and it was studied complex states less discussed in literature, such as the combined effect of two micro elements in steel and the behavior of carbonitrides at high temperatures, varying carbon and nitrogen contents. The studies demonstrate that the nitrides with Titanium have high stability in austenite at elevated temperatures: therefore they are potentially highly effective in grain size control. Carbides with Niobium also present effective stability at high temperatures, as well as the carbonitrides of these two elements. A good correlation was verified between the solubility product obtained either by experimental methods, or by thermodynamics calculation presented by literature. Also, a valuable contribution is made by the software in the studies of precipitation and dissolution of nitrides, carbides and carbonitrides in austenite; thus aiding the selection of steels, and/or modification of the chemical composition of standardized steels, by means of adding micro elements; and providing a suitable choice of carbon and nitrogen content when one seeks to control the grain growth at elevated temperatures. Such results can help indirectly in the studies eliminating conventional heat treatment methods, by using micro alloyed steels with controlled cooling and low alloy steels quenched after forging, with overall reducing costs. Besides these considerations, the results presented and the developed procedure can be useful in other areas where grain growth is an important factor, such as in hot rolling and carburizing at high temperature.

<p>Upotrebom 50% etanola i superkritičnog ugljendioksida kao ekstragensa izvr&scaron;ena je ekstrakcija različitih vrsta pečuraka. Nakon određivanja prinosa suvih ekstrakata, u njima su određeni: sadržaj ukupnih fenola i ukupnih flavonoida, sadržaj makro- i mikro-elemenata, sadržaj adenozina, kao i sadržaj karakterističnih komponenata pistilarina i variegetične kiseline. Najveći sadržaj ukupnih fenolnih jedinjenja određen je u suvom ekstraktu pečurke <em>C. pistillaris</em>, najveći sadržaj ukupnih flavonoida u ekstraktu <em>D. confragosa</em>, a najvi&scaron;e esencijalnog cinka i selena sadrži suvi ekstrakt pečurke <em>B. edulis</em>. U odnosu na ostale suve ekstrakte ekstrakt pečurke <em>L. saccatum</em> sadrži nekoliko puta veću količinu adenozina. Antioksidativno delovanje suvih ekstrakata analizirano je primenom spektrofotometrijskih i EPR metode. Ekstrakti <em>C. pistillaris, B. edulis </em>i <em>A. mellea</em> pokazali su se kao najefikasniji skevindžeri najopasnije slobodnoradikalske vrste hidroksil radikala, dok se efikasnim u prevenciji lipidne peroksidacije mogu smatrati ekstrakti <em>B. edulis, A. mellea </em>i<em> L. saccatum</em>. Nakon određivanja prinosa supekritičnih ekstrakata ispitivanih pečuraka, u njima je analiziran sastav masnih kiselina i detektovana jedinjenja sterolnog tipa. U ispitivanim ekstraktima dominantna je nezasićena linoleinska kiselina, a značajan je udeo i oleinske nezasićene masne kiseline. Dominantno jedinjenje sterolne strukture u gotovo svim ekstraktima je ergosterol. Ispitan je uticaj superkritičnih ekstrakata pečuraka na fluidnost membrane eritrocita i na osnovu dobijenih rezultata zaključeno da bi značajnu ulogu u antihipertenzivnoj ishrani mogle imati pečurke <em>A. mellea </em>i<em> M. procera</em>.</p> / <p>Using 50% ethanol and supercritical carbon dioxide different mushroom extracts were prepared. After analysis of extraction yield, content of total phenols and total flavonoids, content of macro-elements and micro-elements, as well as content of adenosine and characteristic compounds (pistilarin and variegatic acid) were determined. Highest content od total phenols was determined in <em>C. pistillaris</em> extract, highest content of total flavonoids in<em> D. confragosa</em> and highest content of essential zinc and selenium in B. edulis dry extract. In comparsion to other extracts <em>L. saccatum</em> posses few time higher content of adenosine. Antioxidat activity was analysed by spectrophotometric and EPR methods. Extracts of <em>C. pistillaris</em>,<em> B. edulis</em> and <em>A. mellea</em> have been showed as a most efficient in scavenging of dangerous OH˙ radical. In lipid peroxidation prevention significant were mushrooms extracts of<em> B. edulis</em>, <em>A. mellea</em> and<em> L. saccatum</em>.<br />After determination of mushrooms supercritical extraction yield, fatty acid composition and sterol components were analysed. Dominant unsaturated fatty acid in investigated mushroom extracts was linoleic acid. Content of oleic fatty acid was also significant. Dominant compound of sterol structure, in almost all supercritical extracts, was ergosterole. Influence of supercritical mushroom extracts on eritrocite membrane fluidity was investigated. Acording to obtained results, mushrooms <em>A. mellea</em> and <em>M. procera</em> could have significant role in antihypertensive diet.</p>

Thesis (MscAgric (Horticulture))--University of Stellenbosch, 2008. / ‘Brookfield Gala’ apple trees were planted out in July 2003 in a Dundee soil form, consisting of well-aerated sandy loam soil. During the first 12 months trees received young tree solutions high in nitrogen. The nutrient solution of the 2nd leaf trees was based on a yield estimation of 10 ton. ha-1 plus 30%. Nutrient solutions for the 3rd leaf trees were based on 25 ton. ha-1 yield estimations and adapted upwards. Seasonal uptake and distributions were determined for macro and micro elements, using twoand three-year-old apple trees during the seasons 2004/2005 and 2005/2006. In the bearing apple trees the macro nutrient accumulated rapidly from late winter to late autumn. Prior to leaf drop most of the N, P, S, Mg and a small portion of K were redistributed back into the permanent parts of the tree. On the other hand, all Ca in the leaves was lost through leaf drop. Apple fruit contains comparatively large quantities (±60.2%) of K, which are removed during harvest. Guidelines for minimum and maximum nutritional requirements based on the amount necessary to produce 1 kg fruit were determined. For the 3rd leaf trees the minimum macro nutrient requirements (g. kg-1 yield) of N, P, K, Ca, Mg and S were ±1.7, ±0.3, ±2.3, ±0.5, ±0.2 and ±0.2, respectively. The maximum nutrient requirements (g. kg-1 yield) for N, P, K, Ca, Mg and S were ±2.6, ±0.4, ±3.3, ±1.9, ±0.4 and ±0.2, respectively. For the 3rd leaf trees the minimum micro nutrient requirements (mg. kg-1 yield) of Na, Mn, Fe, Cu, Zn, B and Mo were ±75.1, ±1.3, ±28.7, ±0.9, ±3.0, ±5.7 and ±0.3, respectively. The maximum nutrient requirements (mg. kg-1 yield) of Na, Mn, Fe, Cu, Zn, B and Mo were ±102.9, ±7.8, ±32.6, ±1.1, ±6.5, ±7.6 and ±0.3, respectively. Labelled N uptake and distribution for two- and three-year-old apple trees were also determined during the same seasons. The labelled N uptake and distribution results indicated that there was a low labelled N uptake in the initial growth stages, suggesting the importance of internal N reserves for plant development at the beginning of the season. In the active growing period more than 60% of the labelled N was found in the new growth. Uptake efficiency improved as the trees grew older. The effect of different nutrient levels on tree growth, yield and fruit quality was assessed: lower (80%) than the standard (100%) and three higher (120%, 140% and 160%). Results indicated that different nutrient levels had no effect on yield, blush or TSS during the 18 months of application over two bearing seasons. The application of biological products (humic acid, and compost plus compost extract) over a period of 18 months had a significant influence on the TSS, malic acid and citric acid concentrations. A tendency towards an increase in total fine root number and length occured with the addition of biological ameliorant.