Made available in DSpace on 2014-06-11T19:28:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-08-09Bitstream added on 2014-06-13T19:37:06Z : No. of bitstreams: 1 ferreira_ac_me_jabo.pdf: 206579 bytes, checksum: ae1661430b2626c1ec623bac6a3fbb05 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As sementes de milho-doce apresentam a espessura reduzida do pericarpo e maior quantidade de açúcares no endosperma e estas características tornam-nas mais suscetíveis aos danos mecânicos, à entrada e proliferação de patógenos e à deterioração, quando comparadas às de milho comum. Assim, as sementes de milho-doce apresentam menor longevidade no armazenamento e baixo desempenho em campo. O condicionamento fisiológico de sementes e o uso de fitorreguladores podem ser utilizados como técnicas para melhorar o desempenho de sementes. Este trabalho teve como objetivo avaliar os efeitos do condicionamento fisiológico, de fitorreguladores e do armazenamento no desempenho de sementes de milho-doce. Os seguintes tratamentos foram aplicados às sementes: tratamento 1 – sem condicionamento fisiológico; tratamento 2 – com condicionamento fisiológico; tratamento 3 – com condicionamento fisiológico + auxina (50 ppm); tratamento 4 – com condicionamento fisiológico + ácido giberélico (50 ppm) e tratamento 5 – com condicionamento fisiológico + auxina (50 ppm) + ácido giberélico (50 ppm). As sementes foram armazenadas em câmara fria com temperatura de 10 ºC ±1 ºC e umidade relativa do ar de 50% ±5% durante quatro meses. Imediatamente após o condicionamento fisiológico e após quatro meses, foram utilizados os testes de teor de água, teste de germinação, teste de envelhecimento acelerado, teste de frio com solo, teste de condutividade elétrica e teste de emergência de plântulas para avaliar o ensaio. O condicionamento fisiológico com e sem fitorreguladores não teve efeito sobre a germinação e o vigor de sementes de milho-doce, permitindo concluir que estas técnicas não tiveram efeitos positivos na qualidade das sementes de milho-doce nas condições do ensaio / The seeds of sweet corn have reduced the thickness of the pericarp and higher amount of sugars in the endosperm and these characteristics make them more susceptible to mechanical damage at the entrance and proliferation of pathogens and the deterioration when compared to normal corn. Thus the seeds of sweet corn in storage have reduced longevity and poor performance on the field. Priming and the growth regulators can be used as techniques to improve the performance of seeds. This study aimed to evaluate the effects of priming, growth regulators and storage on sweet corn performance. The following treatments were applied to seeds: treatment 1 - no priming; treatment 2 - priming; treatment 3 - priming + auxin (50 ppm); treatment 4 - priming + gibberellic acid (50 ppm) and treatment 5 - priming + auxin (50 ppm) + gibberellic acid (50 ppm). The seeds were stored in cold chamber with temperature of 10 ºC ± 1 ºC and relative humidity of 50% ± 5% for four months. Immediately after the priming and after four months, were used the water content test, germination test, accelerated aging, cold test with soil, electrical conductivity test and seedling emergency test to evaluate the assay. The priming with and without growth regulators had no effect on germination and seed vigor of sweet corn, the report concludes that these techniques did not have positive effects on quality of sweet corn seeds in the assay conditions

Orientador: Roberval Daiton Vieira / Banca: Ana Dionisia da Luz Coelho Novembre / Banca: Claudio Cavariani / Resumo: As sementes de milho-doce apresentam a espessura reduzida do pericarpo e maior quantidade de açúcares no endosperma e estas características tornam-nas mais suscetíveis aos danos mecânicos, à entrada e proliferação de patógenos e à deterioração, quando comparadas às de milho comum. Assim, as sementes de milho-doce apresentam menor longevidade no armazenamento e baixo desempenho em campo. O condicionamento fisiológico de sementes e o uso de fitorreguladores podem ser utilizados como técnicas para melhorar o desempenho de sementes. Este trabalho teve como objetivo avaliar os efeitos do condicionamento fisiológico, de fitorreguladores e do armazenamento no desempenho de sementes de milho-doce. Os seguintes tratamentos foram aplicados às sementes: tratamento 1 - sem condicionamento fisiológico; tratamento 2 - com condicionamento fisiológico; tratamento 3 - com condicionamento fisiológico + auxina (50 ppm); tratamento 4 - com condicionamento fisiológico + ácido giberélico (50 ppm) e tratamento 5 - com condicionamento fisiológico + auxina (50 ppm) + ácido giberélico (50 ppm). As sementes foram armazenadas em câmara fria com temperatura de 10 ºC ±1 ºC e umidade relativa do ar de 50% ±5% durante quatro meses. Imediatamente após o condicionamento fisiológico e após quatro meses, foram utilizados os testes de teor de água, teste de germinação, teste de envelhecimento acelerado, teste de frio com solo, teste de condutividade elétrica e teste de emergência de plântulas para avaliar o ensaio. O condicionamento fisiológico com e sem fitorreguladores não teve efeito sobre a germinação e o vigor de sementes de milho-doce, permitindo concluir que estas técnicas não tiveram efeitos positivos na qualidade das sementes de milho-doce nas condições do ensaio / Abstract: The seeds of sweet corn have reduced the thickness of the pericarp and higher amount of sugars in the endosperm and these characteristics make them more susceptible to mechanical damage at the entrance and proliferation of pathogens and the deterioration when compared to normal corn. Thus the seeds of sweet corn in storage have reduced longevity and poor performance on the field. Priming and the growth regulators can be used as techniques to improve the performance of seeds. This study aimed to evaluate the effects of priming, growth regulators and storage on sweet corn performance. The following treatments were applied to seeds: treatment 1 - no priming; treatment 2 - priming; treatment 3 - priming + auxin (50 ppm); treatment 4 - priming + gibberellic acid (50 ppm) and treatment 5 - priming + auxin (50 ppm) + gibberellic acid (50 ppm). The seeds were stored in cold chamber with temperature of 10 ºC ± 1 ºC and relative humidity of 50% ± 5% for four months. Immediately after the priming and after four months, were used the water content test, germination test, accelerated aging, cold test with soil, electrical conductivity test and seedling emergency test to evaluate the assay. The priming with and without growth regulators had no effect on germination and seed vigor of sweet corn, the report concludes that these techniques did not have positive effects on quality of sweet corn seeds in the assay conditions / Mestre

Resumo: O pinhão-manso (Jatropha curcas L.) é uma oleaginosa da família Euphorbiaceae, que se destaca pelo seu grande potencial sócio econômico e como uma excelente alternativa para a produção de biodiesel. O presente trabalho teve como objetivo principal a padronização e otimização de protocolos de cultivo in vitro para embriões e sementes com adição dos suplementos complexo vitamínico e ácido giberélico em meio MS, visando a obtenção de plântulas assépticas para a extração de explantes que serão utilizados em outros processos de cultura de tecidos e transformação genética para a produção futura de mudas comerciais padronizadas. No primeiro experimento com embriões, em meio MS com sacarose e ágar foram acrescidas várias dosagens de um complexo vitamínico (0,0; 0,5; 1,0; 2,0; 3,0 e 4,0 ml.L-1) e após duas semanas do estabelecimento, dez variáveis foram analisadas. Foi utilizado o delineamento inteiramente casualizado com quatro repetições. Os dados foram submetidos à análise de variância, e as variáveis significativas tiveram suas médias comparadas pelo teste Tukey (5%) e algumas pela regressão polinomial. Os resultados indicaram que a adição de vitaminas ao meio de cultura não é essencial para a germinação e crescimento inicial. No entanto, para a formação de raízes, a presença do complexo vitamínico forneceu incrementos nos resultados. A presença de folhas também respondeu positivamente com o aumento da dosagem de vitaminas. No segundo experimento com as sementes, várias dosagens de ácido giberélico GA3 (0,0; 1,0; 2,0; 4,0; 6,0 e 8,0 mg.L-1) foram acrescentadas em meio MS com sacarose e ágar e após duas semanas dez variáveis foram analisadas. Foi utilizado o delineamento inteiramente casualizado com quatro repetições. Os dados foram submetidos à análise de variância... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The phisic nut (Jatropha curcas L.) is an oil family Euphorbiaceae, which is distinguished by its great potential economic partner and as an excellent alternative to produce biodiesel. The present work had as main objective the standardization and optimization of protocols for in vitro embryos and seeds with the addition of multivitamin supplements and gibberellic acid on MS medium, in order to obtain seedlings for the extraction of aseptic explants to be used in other processes of tissue culture and genetic transformation for the future production of standard commercial seedlings. In the first experiment with embryos in MS medium with sucrose and agar were added various doses of a vitamin complex (0.0, 0.5, 1.0, 2.0, 3.0 and 4.0 ml.l-1) and after two weeks of the establishment, ten variables were analyzed. We used a completely randomized design with four replications. Data were subjected to analysis of variance, and the significant variables had their means compared by Tukey test (5%) and some by polynomial regression. The results indicated that the addition of vitamins to the culture medium is not essential for germination and early growth. However, for root formation, the presence of vitamin complex increments provided in the results. The presence of leaves also responded positively by increasing the dosage of vitamins. In the second experiment with the seeds, various doses of gibberellic acid GA3 (0.0, 1.0, 2.0, 4.0, 6.0 and 8.0 mg.L-1) were added in MS medium with sucrose and agar, and after two weeks ten variables were analyzed. We used a completely randomized design with four replications. Data were subjected to analysis of variance, and the significant variables had their means compared by Tukey test (5%) and some by polynomial regression, as in the first experiment. The results indicated that the... (Complete abstract click electronic access below) / Orientador: Antônio Orlando Di Mauro / Coorientador: Sandra Helena Unêda-Trevisoli / Banca: Bianca Waléria Bertoni / Banca: Jesus Aparecido Ferro / Mestre

The objective of this study was to evaluate the interference of substances with effect of growth regulator, applied to seeds in physiological quality of rice seed subjected to the condition of low temperature stress, seeking to identify the enzymatic mechanism of action of these products, well as their performance on the field, on different sowing dates and cropping systems. For this reason, various experiments were conducted at the experimental of field and in the laboratory using the phytohormone gibberellic acid, the insecticide thiamethoxam and an organo-mineral fertilizer, Haf Plus®. In general, the products tested increased the germination end of most rice cultivars, and their efficiency linked to the existence of low temperature, with greater emphasis on the gibberellic acid, which also influence the final germination, increases seed germination. In cold-sensitive cultivars, as Irga 424, there is no influence of the products in the physiological. The products act beneficially on the antioxidant system of plants, mainly on the activity of superoxide dismutase, reducing free radical production and lipid peroxidation. However, the difference in vigour between the samples were not sufficiently large so that manifest themselves in the field, for the establishment of the crop. As environmental conditions become less favorable, as in an early planting season or in the conventional tillage is a major contribution of the products on the agronomic performance, not reflecting, however, on yield. / O objetivo do presente trabalho foi avaliar a interferência de substâncias com efeito de regulador de crescimento, aplicados via semente, no potencial fisiológico de sementes de cultivares de arroz submetidas à condição de estresse por temperatura baixa, buscando identificar o mecanismo enzimático de atuação desses produtos, bem como seu desempenho em campo, sobre diferentes épocas de semeadura e sistemas de cultivo. Para isso, diferentes experimentos foram conduzidos em área experimental de várzea e em laboratório, utilizando o fito-hormônio ácido giberélico, o inseticida tiametoxam e um fertilizante organo-mineral, Haf Plus®. De maneira geral, os produtos testados aumentam a germinação final da maioria das cultivares de arroz, tendo sua eficiência atrelada a existência de temperatura baixa, com maior destaque para o ácido giberélico, que além de influenciar a germinação final, aumenta o vigor das sementes. Nas cultivares sensíveis ao frio, como Irga 424, não há influência dos produtos no potencial fisiológico. Os produtos atuam de forma benéfica sobre o sistema antioxidante das plantas, principalmente sobre a atividade da enzima superóxido dismutase, diminuindo a produção de radicais livres e a peroxidação lipídica. No entanto, as diferenças de vigor entre as amostras não foram suficientemente amplas para que se manifestassem em condições de campo, em relação ao estabelecimento da lavoura. À medida que as condições do ambiente tornam-se menos favoráveis, como em uma época antecipada de semeadura ou em sistema de cultivo convencional há uma contribuição maior dos produtos sobre o desempenho agronômico, não se refletindo, no entanto, sobre o rendimento.

Our ability to control malaria has been challenged by increasing antimalarial resistance. Plasmodium falciparum undergoes dormancy in the blood stages which is hypothesized to be a means by which they are able to survive under drug pressure. This helps select for resistant parasites which grow following removal of drug. The mechanisms behind dormancy and the subsequent recrudescence are not fully understood but translating knowledge from related organisms which undergo a similar phenomenon might shed some light. Higher plants utilize dormancy during the early development stages to survive under unfavorable conditions, increasing fitness of the seedling and ensuring viability when this is released and it develops into a mature plant. Abscisic acid (ABA) and gibberellic acid (GA) antagonistically regulate this in response to environmental cues. We have found that both can be supplemented to dihydroartemesinin-induced dormant parasites to stimulate early recovery. Fluridone, an ABA inhibitor that releases dormancy in plants, was found to prolong it and cause a delay in recrudescence. These effects were observed in artemisinin sensitive and resistant strains. The apicoplast is required for recovery and supplementation of essential isoprenoid, isopentyl pyrophosphate (IPP), in apicoplast deficient parasites is sufficient enough to compensate for the lack of the organelle in antibiotic treated parasites. IPP plays an important role in development and metabolism of blood stage parasites as a key component of numerous secondary metabolites and protein activity by prenylation of isoprenoids. Its role in dormancy has not been explored prior to this study. Carotenoids are long-chained ABA precursors consisting of two molecules of geranylgeranyl pyrophosphate (GGPP). Several carotenoids as well as enzymes in that pathway have been identified in the blood stages of P. falciparum. The Apicomplexan parasite, Toxoplasma gondii synthesizes ABA, where it plays a role in signaling and development. To date ABA has not been detected in P. falciparum due to limitations in methods previously utilized. We have found that parasites with fosmidomycin inhibition of isoprenoids can be rescued with GGPP supplementation which we planned to use to further elucidate the carotenoid biosynthetic pathway. We hypothesized that Plasmodium has retained the ability to biosynthesize ABA and aimed to confirm this. We developed a novel method to label GGPP with 13C on three of its isoprene units. This would be used to metabolically label isoprenoid inhibited P. falciparum for incorporation through the carotenoid pathway for detection of 13C-ABA.

The use of improved seeded bermudagrasses (SB) has increased. All new cultivars are marketed as coated seed. As germination of many of these new cultivars is less than ideal, questions arise as to the effect coatings have on germination. Five SB cultivars were selected for a series of germination studies. The first study compared coated and uncoated samples of the five cultivars for germination response to six temperature regimes. Overall, commercial seed coating did not affect SB germination. However, both temperature regime and cultivar were significant factors. In a second study, three seed treatments were investigated across three temperature regimes and five SB cultivars to evaluate enhancement of germination. Two of the three treatments improved germination at day 7 indicating increased germination rate. No treatment produced significant results in germination at day 21. Cultivar specific differences regarding treatments were present at all count intervals.

Lavender is an important medicinal plant that is sensitive to various environmental factors. Lavender essential oils have been shown to improve human health in response to many diseases. Lavender is grown all over the world, which indicates its ability to adapt to different climates. There are no reports of its commercial cultivation in Mississippi. It has been proven that there are many factors that directly affect the plant growth and concentration of essential oils in lavender. Studying these factors that affect plant growth and essential oils will be beneficial for lavender producers. The aim of this study is to increase the production of essential oil through cultural techniques and analyze the active compounds of three Lavandula species (L. intermedia, L. angustifolia, L. stoechas) using HPLC (High performance liquid chromatography) and GC-MS (Gas Chromatography, Mass spectrometer) technology. Applications of gibberellic acid, iron chelate, Mycorrhizae, humic acid, DAP, and potash fertilizer were studied to promote plant growth and production of essential oils. The essential oils were extracted using a Soxhlet distillation. The quantity and quality of the essential oils was also evaluated using HPLC and GC-MS. The linalool, linalyl acetate, and other compounds from Lavandula may be considered natural raw material source for pharmaceuticals and cosmetic products. These vital components of the essential oil of lavender leaves, flowers, and stems (linalool, linalyl, and other compounds) were affected by chelated iron treatments, gibberellin, humic acid, and mycorrhizae. The essential oil compounds of L. angustifolia and L. x intermedia cultivars make them worth cultivating.

No description available.

Organometallic chemistry is highly dependent upon the ligands which are employed on a metal's surface. These ligands control steric bulk and electronics of the metal center which can change the reactivity of the organometallic complex. Ligands that are standard in organometallic chemistry include phosphine ligands. These phosphine ligands have been utilized in the field since the 1960's and have shaped the development of many key organometallic catalysts. Phosphine ligands are easily functionalized and highly reactive. This increased reactivity, however, causes severe limitations as phosphine ligands are often unstable under standard benchtop conditions and must be handled both air and moisture free environments. To combat some of these issues new ligand types have emerged such as N-heterocyclic carbene ligands. These ligands are found to possess similar reactivity in terms of electron and steric influences but can be prepared and used on the benchtop. In this work we highlight a dual N-heterocyclic carbene/phosphine ligand which is obtained from an accessible 2-phosphinoimidazole. These 2-phsophinoimidazole ligands can undergo a transformation in the presence of a proton source. The proton source will cause the disassociation of the C-P bond forming a NHC-phosphine complex. Addition of a metal source to the NHC-phosphonium complex causes a NHC/phosphine metal complex, which upon further investigation was found to be catalytically active. This activity was tested in various cross coupling reactions which include Suzuki, Heck, and Sonogashira. Highlights of these results include the extreme functionalization of these 2-phosphinioimidazole ligands which can produce new aryl groups on the NHC, a free N-H bond on the imidazole which can be deprotonated or influence intermolecular forces with substrates, replacing the moieties on the phosphine, and finally the ability to transform in situ with the addition of a common alcohol. Each of these functionalization's are explained below along with their reactivity to isolate a wide variety of substrates. In addition to the work above a collaboration with Rio Tinto and the Madsen Lab at BYU is discussed. This work involves the concerns of land managers and their ability to restore landscapes that have been destroyed through a variety of issues including fire, mining, and invasive species. These ecological pressures cause land managers to search for native plants to seed on a landscape. Issues arise when using natives, however, because of their inability to quickly germinate and establish on a landscape. This is caused by dormancy issues where an antagonistic relationship between gibberellic acid and abscisic acid where the overproduction of one over the other results in dormant native plants. We have invented a methodology to use slow releasing polymers to hijack this system and deliver gibberellic acid to a seed causing it to germinate regardless of external stimuli. Our results show significant improvement in native Penstemon species with no side effects to the plant growth and establishment.

Experiments were conducted to study the effect of gibberellic acid on palatability and digestibility of two grasses, orchard grass and Kentucky 31 fescue. The GA was applied as a spray, except one granular application, at rates of 18 to 72 gm./A. Sheep were used to test the grass for palatability and digestibility. In addition to proximate analysis of grass, data were obtained on soluble carbohydrate, cellulose and lignin contents. Chemical composition of orchard grass was not affected by GA treatment. The most consistent effect of GA on the chemical composition of fescue was a depression of protein content. Ash content was decreased slightly, but consistently. GA increased crude fiber in two experiments; did not affect it in three. Nitrogen free extract was increased slightly in three of the five tests. Cellulose was increased by GA in the summer and fall of 1960, but not in the spring. Lignin was increased in the spring of that year and decreased in the summer and fall. Ether extract and soluble carbohydrate contents were not consistently affected by GA. In general, chemical changes by GA were less than 5%. Orchard grass palatability was improved by GA. In two out of three trials with Kentucky 31 fescue, consumption of GA treated grass was about 38% less than for the control. Irrigation increased palatability, probably due to a large difference in moisture content of the grass. No chemical differences observed were consistently related to selection of grass by the sheep. Digestibility of dry matter in grass tended to be decreased by GA in four out of five experiments. These depressions were less than 5% and in only two cases were they significant. Digestibility of protein, crude fiber, nitrogen free extract and cellulose tended to be decreased and ether extract was made more digestible by GA. Due to the small changes in both digestibility and chemical composition caused by GA no clear-cut explanations could be given for the reduction of digestibility. The effect seems related to a slight protein reduction and in some cases to an increase in crude fiber and cellulose. Although a number of factors which may affect GA response (time after application, growth rate of grass, light intensity, temperature, etc.) have not been studied, it seems unlikely that this growth regulator will exert much effect on the factors controlling digestibility of grass under field conditions. The effect on palatability is more pronounced, but not consistent. The digestibility of fall grown fescue increased with age. This increase probably resulted from accumulation of soluble carbohydrates and decreases in crude fiber, cellulose, and lignin contents in the grass. / Ph. D.