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dc.contributor.advisorPotgieter, G. P.
dc.contributor.authorPretorius, Hendri
dc.date.accessioned2016-01-08T09:26:46Z
dc.date.available2016-01-08T09:26:46Z
dc.date.copyright2009-11-30
dc.date.issued2012-03-22
dc.date.submitted2009-11-30
dc.identifier.urihttp://hdl.handle.net/11660/2070
dc.description.abstractEnglish: A company, Elementol (Pty) Ltd, requested the evaluation of their novel product, Pheroids. Pheroids can apparently facilitate the transport of phytological beneficial substances over membranes. Information regarding the chemical attributes was withheld as patent registration is still pending. Pheroids is apparently a microemulsion containing free fatty acids (FFA’s) and or fatty acid derivatives. It apparently encapsulates a substance and facilitates its transport over the membrane. The exact mechanism involving encapsulation, transport and release of the substances inside the cells is still vague due to little information available on it. The aim of this study was to evaluate the ability of Pheroids to facilitate the transport of additional nitrogen, urea in this case, in tomatoes grown under nitrogen limiting conditions. Tomatoes (Lycopersicon esculentum cv. Rodade Star) were cultivated in a greenhouse using a circulating ebb and flow hydroponic setup, which supplied the plants with either a control- or nitrogen limiting nutrient solutions. The plants cultivated in the nitrogen limiting conditions showed a remarkable reduction in vegetative development and yield. To alleviate the effect of nitrogen limiting conditions on yield, the plants were foliarly sprayed with 0.5% and 1% urea solutions, singly or mixed with Pheroids, once every two weeks. The purpose of these foliar treatments was to determine whether Pheroids can further enhance the absorption and transport of urea across membranes of the leaves to alleviate the effect of limiting nitrogen supply. Plants grown under nitrogen adequate conditions (control) were also foliarly treated with a 0.5% urea solution, singly and mixed with Pheroids, to determine to which extent control plants react to the additional nitrogen supplied. The reduction in yield, as a result of limited nitrogen supply, was partially alleviated by spraying nitrogen deficient plants with the 0.5% and 1% urea solutions. However, mixing the 0.5% and 1% urea solutions with Pheroids, not only improved vegetative growth and generative development, but also improved yield, suggesting that Pheroids indeed has the ability to improve the uptake of urea. The 0.5% urea / Pheroids solution specifically proved to have the best ability in alleviating the effect of nitrogen limiting conditions on yield without compromising fruit quality. Although the reducing effect was not completely alleviated, the yield and loss in income as a result of nitrogen limiting conditions was prevented to a large extent. Spraying control plants with 0.5% urea, singly or mixed with Pheroids, also improved yield, without compromising fruit quality. In addition, Pheroids itself, without mixing it with any substance, also resulted in increased yields in both control- and plants grown under nitrogen limiting conditions. In summary, it appeared that Pheroids has the ability to facilitate the transport of phytological beneficial substances, in this case urea, over plant membranes and enhances cellular nitrogen content, but this needs further detailed analyses. This phenomenon was more evident in plants grown under nitrogen limiting conditions than in plants grown under control conditions. Taking into consideration that most crops frequently may suffer from nitrogen limiting conditions in standard agricultural practices, Pheroids may have numerous potential applications in the agricultural industry.en_ZA
dc.description.abstractAfrikaans: ‘n Maatskappy, Elementol (Edms) Bpk, het die evaluering van hul produk “Pheroids” aangevra. Pheroids beskik vermoedelik oor die eïenskap om die vervoer van fitologiese voordelige verbindings oor membrane te fasiliteer. Inligting rakend die chemiese eïenskappe van Pheroids was weerhou aangesien patentregistrasie nog hangende was. Pheroids is vermoedelik ‘n mikro-emulsie bestaande uit vry vetsure en afgeleide vetsure. Pheroids “verpak” die verbindings waarna hierdie Pheroids / verbindingskompleks deur die membraan beweeg. Die presiese meganisme rakend “verpakking”, vervoer en vrystelling van verbindings in die sel is onduidelik, as gevolg van die beperkte inligting bekend oor die werking en samestelling van Pheroids. Die doel van die studie was om die vermoë van Pheroids te ondersoek om die opname van voordelige verbindings, in dié geval ureum, in tamaties te verhoog deur dit onder stikstofbeperkende toestande te verbou. Tamaties (Lycopersicon esculentum cv. Rodade Star) was in ‘n kweekhuis verbou met behulp van ‘n sirkulerende “ebb and flow” hidroponiese stelsel. Die stelsel het die plante van kontrole- en stikstofbeperkende groeimedia voorsien. Die plante wat onder stikstofbeperkende toestande verbou was, het ‘n sigbare verlaging in oesopbrengs getoon. Om die negatiewe invloed wat stikstofbeperkende toestande op oesopbrengs het te oorkom, is die plante elke twee weke met 0.5% en 1% ureum oplossings, alleen of vermeng met Pheroids, bespuit. Die doel van hierdie blaarbespuitings was om vas te stel of Pheroids die opname van ureum bevorder en sodoende die invloed van stikstofbeperkende toestande op groei en oesopbrengs te beperk. Kontrole-plante was ook met ‘n 0.5% ureum oplossing, alleen of met Pheroids vermeng, bespuit. Dit was gedoen om vas te stel of kontrole-plante ook op die addisionele stikstoftoedienings reageer. Die afname in oesopbrengs, as gevolg van stikstofbeperkende toestande, is gedeeltelik opgehef wanneer plante met die 0.5% en 1% ureum oplossings bespuit word. Deur die 0.5% en 1% ureum oplossings met Pheroids te vermeng, kon die effek van stikstofbeperkende toestande op vegetatiewe groei, generatiewe ontwikkeling en oesopbrengs verder opgehef word. Dit dui daarop dat Peroids wel oor die vermoë beskik om ureumopname te verhoog. Die 0.5% ureum / Pheroids mengsel was die mees suksesvolle behandeling om die invloed van lae stikstofvlakke op groei en ontwikkeling te beperk. Alhoewel die negatiewe invloed nie ten volle opgehef kon word nie, was die verlies in oesopbrengs en gepaardgaande inkomste wel tot ‘n groot mate beperk. Kontrole-plante wat met 0.5% ureum, alleen of met Pheroids vermeng, bespuit is het ook positief op die bespuitings gereageer deur ‘n hoër oesopbrengs te lewer. Pheroids alleen as behandeling het ook ‘n toename in oesoprengs tot gevolg gehad by die plante wat onder stikstofbeperkende toestande verbou was. Dit blyk dus dat Pheroids wel die potensiaal besit om verbindings soos ureum se vervoer oor plantmembrane te fasiliteer, om sodoende waarskynlik die sellulêre stikstofvlakke te verhoog. Hierdie verskynsel benodig egter nog verdere ondersoek. Die invloed van Pheroids was egter meer opvallend by die plante wat onder stikstofbeperkende toestande verbou was. As daar in ag geneem word dat die meeste gewasse van tyd tot tyd stikstofbeperkende toestande ervaar, blyk dit dat Pheroids groot toepassingspotensiaal in die landboukundige industrie mag hê.af
dc.description.sponsorshipUniversity of the Free Stateen_ZA
dc.language.isoenen_ZA
dc.publisherUniversity of the Free Stateen_ZA
dc.subjectDissertation (M.Sc. (Plant Sciences (Botany))--University of the Free State, 2009en_ZA
dc.subjectTomatoes -- Fertilizersen_ZA
dc.subjectFertilizers -- Applicationen_ZA
dc.subjectCrops and nitrogenen_ZA
dc.subjectUrea as fertilizeren_ZA
dc.subjectHydroponicsen_ZA
dc.subjectLycopersicon esculentumen_ZA
dc.subjectPheroidsen_ZA
dc.subjectElementolen_ZA
dc.titleThe ability of a novel compound to enhance the effect of urea on nitrogen deficient tomatoesen_ZA
dc.typeDissertationen_ZA
dc.rights.holderUniversity of the Free Stateen_ZA


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