• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 146
  • 56
  • 41
  • 36
  • 10
  • 7
  • 5
  • 4
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 325
  • 197
  • 61
  • 48
  • 44
  • 42
  • 42
  • 41
  • 37
  • 29
  • 27
  • 27
  • 22
  • 22
  • 22
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Descripción de los componentes del rendimiento de uva de mesa variedad Flame Seedless

Salazar Fernández, Daniela Alejandra January 2012 (has links)
Memoria para optar al título profesional de Ingeniera Agrónoma Mención Fruticultura / Con el objetivo de describir el comportamiento de una serie de variables que influyen en el rendimiento, en función del vigor de las plantas y apoyada en una planilla electrónica, se realizó un estudio durante la temporada 2010/2011 en un parronal de la variedad Flame Seedless, ubicado en la localidad de La Arena, Región de Atacama. Se trabajó con una planilla electrónica que integra los factores vegetativos y productivos que afectan el rendimiento de las plantas y permitiendo realizar la estimación de cosecha expresada en cajas exportables de 8,2 kg, diferenciando los datos de acuerdo al vigor de las plantas que compone el cuartel. Inicialmente se entrevistó al administrador del predio para completar la información de la planilla, sin tomar en cuenta el vigor de las plantas, con el fin de obtener un rendimiento probable del cuartel (2,4 ha) para la temporada en curso. Posteriormente y en el cuartel en cuestión, se escogieron 24 plantas que fueron diferenciadas entre si en función de su vigor, evaluado mediante el área de sección transversal de tronco (ASTT), área foliar y peso de poda, formando 3 grupos, de 8 plantas cada uno: vigor 1, vigor 2 y vigor 3. Luego se procedió a realizar una serie de evaluaciones en campo, entre ellas número de yemas, cargadores y brotes por planta. En cosecha, cuando los racimos alcanzaron 16,5° Brix de sólidos solubles, se evaluó el tamaño de baya (diámetro ecuatorial y polar), peso de baya y parámetros de calidad como peso, color y morfología de racimo. En este estudio hubo efectos de la variabilidad del vigor sobre el rendimiento final, ya que para el caso de estimación de cosecha realizada con los datos de campo (que incluye las diferencias por vigor), se obtuvo una estimación de cosecha de 4.667 cajas exportables de 8,2 kg y de 5.306 por el administrador del predio. Dichas estimaciones fueron comparadas con la producción real obtenida para la temporada 2010/2011 (4.594 cajas de 8,2 kg) obteniéndose un mejor resultado con la metodología implementada en este estudio. De igual forma la planilla entregó información clave con respecto al follaje de las plantas, presentando diferencias en cuanto a la cantidad de follaje disponible para llevar a madurez la fruta dejada en las plantas. Se puede observar que el administrador no considera para su estimación las condiciones de las hojas y brotes del campo, por lo que muchas veces se sobreestima la cantidad de fruta que podrá llegar a cosecha en condiciones exportables. Se prueba también que la planilla electrónica entrega una estimación de cosecha mucho más certera al tomar en cuenta todos los factores que la componen, pero más aún, al diferenciar estos de acuerdo a las condiciones de vigor de las plantas. Se hace necesario entonces, reconocer y diferenciar los distintos tipos de vigor presentes en el predio para realizar labores de manera diferenciada con el fin de obtener rendimientos de acuerdo al potencial de las plantas y así una estimación de cosecha más precisa. / In order to describe the performance of a series of variables influencing yield according to plant vigour, and supported by an electronic spreadsheet, research work was carried out during the period 2010 / 2011 in a table grape vineyard cv. Flame Seedless, in “La Arena”, “Atacama Region”, Chile. An electronic spreadsheet was used to integrate vegetative and productive factors influencing plant yield and to get an estimation of harvest expressed in 8.2 kg exportable boxes, differentiating the data according to plant vigor across the blocks. At the beginning, the field manager was interviewed in order to fill data sheet information, without considering grapevines vigor, with the purpose of getting the block probable yield (2.4 ha) for the current season. Afterwards, 24 plants were chosen, and differentiated among each other, according to their vigor, evaluated by the cross-sectional area of trunk (“ASTT”), leaf area and pruning weight, forming 3 groups of 8 grapevines each: vigor 1, vigor 2 and vigor 3. Then, a series of field evaluations including: number of buds, canes, and shoots per plant. At harvest, when cluster reached 16.5° Brix of soluble solids, the following evaluations were done: berry size (equatorial and polar diameter) and weight, and cluster weight, color and morphology. The study indicates, effects of vigor over final yield, since harvest estimation with the field data (which includes vigor differences), was 4,667 exportable boxes of 8.2 kg, while. the field manager’s expected yield was 5,306 boxes of 8.2 kg. These estimations were compared with the real production obtained for season 2010 / 2011, which was 4,594 boxes of 8.2 kg closer the field data but relatively far from manager estimation. Similarly, the data spreadsheet provided information related to the foliage of plants, showing some differences on foliage available to ripe the fruit left on the plants. The field manager does not consider leaf and shoot conditions in his estimation; therefore many time fruit quantity that can be able to be produced could be overestimated. Additionally, it is demonstrated that the spreadsheet gives a much more accurate harvest estimation when considering all factors affecting it, but even more, when differentiating them according to the vigor plant conditions. Thus, it is necessary, to recognize and differentiate among different vigor types in the property to determine differentiate field works, in order to obtain yields in accordance with plants potential and by this way to get a yield more accurate estimate.
32

Efecto de la carga frutal en la producción y calidad en uva de mesa "Sultanina"

Pinochet Zúñiga, Carolina Patricia January 2011 (has links)
No disponible a texto completo / Memoria para optar al Título Profesional de Ingeniero Agrónomo Mención: Fruticultura / En la temporada 2003 – 2004, en la Comuna de Nancagua, se realizó un estudio para determinar el efecto de la carga frutal sobre la producción y calidad en uva de mesa variedad Sultanina (Thompson Seedless). Se evaluó distintos niveles de carga frutal, ajustando el número de racimos por planta y número de bayas por racimo. El número de racimos fue ajustado a 20; 30; 40; 50; 60 ó 70 racimos por planta, durante la labor de “descarga de racimos”; antes de plena flor. Posteriormente, en el momento de “arreglo de racimos”, con bayas entre 4 y 5 mm de diámetro, se ajustó el número de bayas por racimo en rangos de 80 a 120 bayas, 120 a 160 bayas y 160 a 200 bayas, rangos bajo (B), medio (M) y alto (A) respectivamente. El ensayo fue completamente al azar, con arreglo factorial de tratamientos 6 x 3, con un total de 18 tratamientos, siendo la unidad experimental la planta. Existió un efecto significativo de la carga frutal sobre el rendimiento por planta, aumentando en el mayor nivel de carga frutal; similar respuesta, pero inversa, se obtuvo en el tamaño de bayas. El número de bayas por racimo afectó a la producción total y exportable de la planta, al peso promedio de racimos y a la proporción de desecho de fruta. Sin embargo, para sólidos solubles, acidez titulable, firmeza, número de brotes iniciales y finales, tanto el número de racimos por planta como número de bayas por racimo no afectaron estos parámetros, lo mismo para área sección transversal inicial y final del tronco. La carga frutal y número de bayas, determinados en este ensayo como óptimo, para cosechar fruta de exportación de buena calidad y sin retrasar la cosecha, fue de 60 racimos por planta, con un rango de entre 120 a 160 bayas por racimo; haciéndose más difícil el manejo operacional en la descarga y arreglo de racimo en la medida que se incrementan los niveles de carga. / In the season 2003 - 2004, in the Commune of Nancagua, a study was conducted in order of to determine the effect of crop load on yield of Thompson Seedless table grape (Sultanina). We evaluated different levels of crop load, as bunches per plant and berries per cluster. The cluster per plant was set to 20; 30; 40; 50; 60 or 70, during cluster thinning and before full bloom. Later, during berry hand thinning berries per cluster was adjusted between 80 and 200, obtaining three distinct ranges low (B), medium (M) and high (A). Crop load significantly affected yield per plant, increasing it as crop load was higher; an inverse behaviur was obtained for size berry. Berries per bunch proportionally affected to total yield and export per plant, bunch weight and discarded fruit. However, soluble solids, acidity, firmness, shoots number, and trunk cross-sectional area at the beginning and at the end of the season were not affected by crop load. In the optimum crop load of this vineyard was established at 60 clusters per plant, with clusters range of 120 to 160 berries per cluster. That crop load permits harvest is high quality export fruit without delaying the harvest; a higher levels of crop load cluster and berry thinning of to be regimens amount of it labor.
33

Efecto del lixiviado de riego de cultivos utilizados como cobertura sobre vid de mesa de un año de edad

Laborie Guerra, Denisse Alessandra Bernabé January 2011 (has links)
Memoria para optar al Título Profesional de Ingeniero Agrónomo Mención: Fitotecnia / En el Valle de Copiapó, las condiciones climáticas se presentan favorables para el desarrollo de la vid (Vitis vinífera), sin embargo, los suelos de la zona son sensibles al deterioro físico producto del manejo agrícola (alta intensidad de uso y bajos niveles de materia orgánica). Con respecto al último punto se han evaluado diferentes manejos entre los cuales se encuentra el uso de cultivos de cobertura, sin embargo no existen antecedentes de efectos alelopáticos generados sobre vides. Por este motivo, se llevó a cabo el presente estudio donde se evaluó el efecto de lixiviados provenientes del agua de riego de cebada, haba, mostaza y sordán sobre el crecimiento de vid variedad Sultanina de un año de edad. El ensayo se realizó con un diseño experimental completamente al azar y contempló 5 tratamientos conformados por plantas de vid que crecieron en contenedores individuales, las cuales se regaron con el lixiviado de riego proveniente de los cultivos de cobertura antes mencionados y sembrados en forma independiente a las plantas de vid, además de un testigo sin cultivo; cuando éstos alcanzaron el 50% de floración, fueron segados y dejados sobre la misma superficie continuando el riego, utilizando el lixiviado correspondiente, hasta que las vides cesaron de crecer. Se midió altura de planta, diámetro del tronco, número de hojas y longitud de brotes. Además, al finalizar el periodo de crecimiento de la vid se midió materia fresca y seca de la parte aérea y de raíces. Los resultados indican que existieron reducciones estadísticas significativas en longitud de brotes y número de hojas en las plantas de vid para los tratamientos de cebada, mostaza y sordán, manifestándose estas diferencias en etapas previas y posteriores al corte de los cultivos. También se observó una menor acumulación de materia fresca y seca en brotes de vid en el tratamiento de cebada, sin detectar diferencias en peso de las raíces. Las variables altura de planta y diámetro del tronco no presentaron diferencias estadísticas. Debido a que en este ensayo no existió competencia entre los cultivos y las vides, el efecto de reducción del crecimiento se atribuiría a algún tipo de exudado generado por los cultivos de cobertura y/o residuos de éstos, compuestos que al ser lixiviados por el agua de riego afectarían el crecimiento de la vid. / In the Copiapo valley, climatic conditions are favorable for vine agriculture (Vitis vinífera), however, the soils of the area are very sensitive to physical damage because of agriculture management, such us high intensity use and low levels of organic matter in the soil). The latter effect has been study with several kinds of management, nevertheless, there is no information of the allelopathic effects produced in vine. For this reason a study was developed to evaluate the effect of leachate irrigation water from barley, beans, mustard and sordan on the growth of a one year old ‘Sultanina’ vine variety. This work was performed using a completely randomized design with five treatments. In each treatment vines were grown in individual containers and they were irrigated with the differents leachates of the cover crops, and an untreated sample. Once the plants reached the 50% flowering state, they were harvested and left in the containers with each leachate irrigation until the vines stopped growing. Several measuring parameters were obtained in the course of the experiment like plant height, stem diameter, leaf number and shoot length. At the end of growing period fresh and dry weigth of foliage and roots were measured. Results showed statistically significant reductions in shoot length and leaf number for the barley, mustard and sordan treatments, which were recorded before and after the crops harvest. We also observed a reduced accumulation of fresh and dry weight in vine shoots irrigated with barley leachate, with no differences in root weight. Also, plant height and stem diameter were not statistically different compared with the control. Because in this trial no competition occurred between the crops and vines, slow vine growth was attributed to some type of exudate or residue produced by the plants that affect vine growth when irrigated with this leachate.
34

IRRADIAÇÃO UV-C EM CULTIVARES DE UVAS NIÁGARA BRANCA, TREBBIANO, ISABEL E CABERNET SAUVIGNON / RADIATION UV-C IN NIÁGARA WHITE, TREBBIANO, ISABELLA AND CABERNET SAUVIGNON

Treptow, Taísa Ceratti 29 February 2012 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study evaluated the UV-C irradiation in tissues of rachis with and without berries, and berries with stems of Vitis vinifera and Vitis labrusca. In berries of cv. Isabella, the volatile compounds were analyzed on days 2, 5 and 10 of storage at 20 ºC and the effect of UV-C irradiation on the 5th day of storage. The experiments were based on four treatments of UV-C radiation (0, 1, 2 and 3 kJ m-2) with four cv. (Niagara white, Trebbiano, Cabernet sauvignon and Isabella) and evaluation times (three in berries and four rachis). The rachis with and without berries and the berries with stems remained stored at 20 ºC to evaluate physiological parameters. Ethylene production rate, respiratory rate and total polyphenols were evaluated in all tissues. Only in the rachis was determined by weight loss on days 1, 3 and 5, reducing sugars, non-reducing sugars on the 5th day. Berries and the juice from the cv. Isabella the 5th day of storage at 20 °C the total soluble solids (TSS), titratable acidity (TA), anthocyanins, total phenols, sugars and the ratio (TSS/ TA) were measured. In berries of cv. Isabella on days 2, 5 and 10 storage and berries irradiated with UV-C in amounts of 0, 1, 2 and 3 kJ m-2, volatiles were extracted by solid phase microextration. After desorption, the volatile compounds were separated by gas chromatography, identified by mass spectrometry and quantified by flame ionization detector. For the sensory analysis of the juice discriminatory tests for paired comparison of difference and test ranking were used. The physiological response of UV-C irradiation depends on the cv. and the irradiated tissue. Only the rachis of grape Vitis labrusca ‗Niagara white behaves climateric during storage in post-harvest and may reduce the self life of table grapes. This study found a possible hormetic dose of 3 kJ m-2 only for the cv. Isabella berry. 84 volatile compounds were detected over the days of storage. After 5 days storage, berries irradiated with UV-C 66 volatiles were found. And the dose of 3 kJ m-2 increased the concentration of esters and aldehydes, and 43,8% increase in the total polyphenols in berry. In the paired comparison test of difference, the judges showed greater intensity in the aroma of the juice from grapes irradiated. In the ranking test, the judges were unable to discriminate between different doses of irradiation, though differing dose control (0 kJ m-2) of the irradiated treatments. The analytical test enabled by gas chromatography to determine statistical differences between the different doses detected volatiles, especially at a dose of 3 kJ m-2, in which panelists found no difference. / Este trabalho avaliou a irradiação UV-C em tecidos vegetais de ráquis com e sem bagas, e bagas com pedúnculo de Vitis vinifera e Vitis labrusca. Nas bagas da cv. Isabel, foram analisados os compostos voláteis nos dias 2, 5 e 10 de armazenamento a 20 ºC e sobre o efeito da irradiação UV-C no 5º dia de armazenamento. Os experimentos basearam-se em quatro tratamentos de irradiação UV-C (0, 1, 2 e 3 kJ m-2), com quatro cv. (Niágara branca, Trebbiano, Isabel e Cabernet sauvignon) e tempos de avaliação (três nas bagas e quatro nas ráquis). As ráquis com e sem bagas e as bagas com pedúnculo permaneceram armazenadas a 20 ºC para avaliar parâmetros fisiológicos. Em todos os tecidos foram avaliadas a taxa de produção de etileno, taxa respiratória e polifenóis totais. Apenas na ráquis foi determinado a perda de peso nos dias 1, 3 e 5, além de açúcares redutores e não redutores no 5º dia. Nas bagas e no suco da cv. Isabel do 5º dia de armazenamento a 20 ºC foram mensurados os sólidos solúveis totais (SST), acidez total titulável (ATT), antocianinas totais, polifenóis totais, açúcares totais e a relação (SST/ATT). Nas bagas da cv. Isabel dos dias 2, 5 e 10 de armazenamento e nas bagas irradiadas com UV-C nas doses de 0, 1, 2 e 3 kJ m-2, foram extraídos os compostos voláteis por microextração em fase sólida. Após a dessorção, os compostos voláteis foram separados em cromatógrafo a gás, identificados pelo espectrômetro de massas e quantificados por detector de ionização em chamas. Para a análise sensorial do suco, foram utilizados os testes discriminativos de comparação pareada de diferença e teste de ordenação. A resposta fisiológica da irradiação UV-C depende da cv. e do tecido irradiado. Apenas a ráquis da uva Vitis labrusca ‗Niágara branca se comporta de forma climatérica durante o armazenamento na pós-colheita, podendo reduzir a vida de prateleira da uva de mesa. Neste estudo foi encontrada uma possível dose hormética de 3 kJ m-2 somente para a baga da cv. Isabel. Foram detectados 84 compostos voláteis ao longo dos dias de armazenamento. No 5º dia de armazenamento, das bagas irradiadas com UV-C, foram encontrados 66 compostos voláteis, sendo que a dose de 3 kJ m-2 aumentou a concentração de ésteres e aldeídos, além de elevar em 43,8% os polifenóis totais na baga. No teste de comparação pareada de diferença, os provadores indicaram maior intensidade no aroma do suco proveniente de uvas irradiadas. No teste de ordenação, os julgadores não conseguiram discriminar as diferentes doses de irradiação, mas diferenciaram a dose controle (0 kJ m-2) dos tratamentos irradiados. O teste analítico por cromatografia gasosa permitiu determinar diferença estatística entre as doses nos diferentes compostos voláteis detectados, principalmente na dose de 3 kJ m-2, na qual os julgadores não encontraram diferença.
35

Development of a reporter system for the analysis of xylophilus ampelinus type III secreted effectors

Nyembe, Nompumelelo Philile Praiseworth January 2014 (has links)
>Magister Scientiae - MSc / Xylophilus ampelinus, the causal agent of bacterial blight and canker of grapevines, has long been a threat to the table grape industry in the Western Cape, leading to severe economic losses due to the reduced productivity and shortened lifespan of infected grapevines. Very little is known about the genetic makeup of the organism, especially with regard to the factors that contribute to its pathogenicity. Generally, bacterial pathogens directly inject the effector proteins into host cells via Type III secretion system (T3SS). In the attempts to identify and characterize the T3 secreted effectors, different reporter plasmid systems have been used to study the secretion and translocation mechanisms the effectors employ during pathogenicity. The aim of the study was to generate a T3 reporter plasmid system for X. ampelinus that will allow the identification and classification of potential pathogenicity factors as members of the Type III secretion class of effectors. First, the avrBs1 family genes avrBs1 and avrA were identified and characterized. The two avirulence genes induced HR on Nicotiana tabacum leaves. Due to the relatedness of the X. ampelinus avr sequences to those of xanthomonads, and the fact that Xanthomonas avrBs1 has been successfully used in a number T3 effector studies, it was decided to construct an X. ampelinus T3 effector reporter vector based on the avrBs1 gene. The minimal segment of the X. ampelinus AvrBs1 protein C-terminus, sufficient for recognition inside host cells and also responsible for HR-induction was identified and characterized using Agrobacterium-mediated transient expression. The AvrBs157-413 HR-inducing domain was cloned in-frame with the 3x FLAG epitope, into a broad-host range vector. To test the reporter vector, the full length avrBs1 sequences of X. ampelinus and Xanthomonas campestris pv. campestris were cloned ahead of the 3x FLAG epitope and the constructs were transferred into XaΔavrBs1 knockout mutant to test for protein secretion. Furthermore, the reporter construct was tested for Type III protein translocation on Bs1 resistant pepper cultivar STAR 6657. Optimization of protein secretion and translocation assays is however required for the improved results. This might include the application of an alternative protein tag to identify candidate X. ampelinus T3SS effectors.
36

Effects of Horticultural Oils on Photosynthesis, Fruit Maturity, and Yield of Wine Grapes

Finger, Sarah Adine 26 May 2000 (has links)
In field experiments conducted in northern Virginia during 1998, oils reduced photosynthesis, fruit maturity, and crop yield. Three applications of a 1.5% (v/v) oil/water emulsion were made to Chardonnay and Cabernet Sauvignon vine canopies at 6200 L/ha (Chardonnay) and 2440 L/ha (Cabernet Sauvignon). Net assimilation rate (NAR), soluble solids concentration (SSC), and berry size were reduced by oil treatments when compared to an untreated control. Also in 1998, a 1.5% (v/v) oil/water emulsion at 5550 L/ha and 4680 L/ha was applied to 23 wine grape cultivars. Eleven cultivars had significant foliar injury but injury was not related to reductions in fruit maturity. Experiments conducted in 1999 determined if reduced spray volumes or applications to only the fruit zone minimize reductions in NAR and SSC. Chardonnay and Cabernet Sauvignon were treated with JMS Stylet oil (1.5%) using 5600 L/ha or 1870 L/ha applied to the whole canopy or 930 L/ha applied to the fruit zone. The NAR of 5600 L/ha treated Cabernet Sauvignon was significantly lower than the NAR of control and other oil treatments on three measurement dates. The NAR of Chardonnay in the 5600 L/ha treatment was significantly lower than the NAR of control treatments in three measurements. Cabernet Sauvignon SSC was reduced by the 5600 L/ha and 1870 L/ha treatments, relative to the water treated control, on three sample dates but not at harvest. The SSC of Chardonnay in the 5600 L/ha treatment was reduced at harvest as compared to all other treatments. The SSC of Chardonnay in the 1870 and 930 L/ha treatments was reduced relative to the water control. Low volumes of oil caused less reduction in NAR and SSC; however, there are concerns about the efficacy of oils used at low volumes due to poor coverage. / Master of Science
37

Effects of Pruning Level and Canopy Management Practices on Berry Maturation Rate and Harvest Parameters of Syrah Wine Grapes

Landolt, Jeffery S. 01 March 2011 (has links) (PDF)
Syrah is an important wine grape in California but is potentially difficult to manage in the vineyard due to its excessive vigor. Vigorous grapevines require more labor for canopy management and tend to create excess shade, decreasing fruit quality. Winter pruning level, shoot thinning and leaf removal influence the overall density of the canopy and the subsequent degree of shade in the fruit zone. An experiment was conducted to assess the effects of two pruning levels with three degrees of labor-intensive canopy management techniques on berry maturation rate and harvest berry parameters for two growing seasons. In 2008, repeated measures analysis showed no significant effects of severe pruning, shoot thinning or both sides leaf removal on maturation rate of performance indicators. At harvest 2008, severe pruning caused a decrease in yield/meter trellis and Ravaz index. In 2009, repeated measures analysis showed significant effects of severe pruning increasing brix, pH and sugar to acid ratio while shoot thinning and both sides leaf removal had no significant effects on maturation rate of performance indicators. At harvest 2009, severe pruning increased brix, pH, tannin, anthocyanins, phenolics, color density, potassium, amino acid % of yeast assimilable nitrogen (YAN), and the following ratios: sugar/acid, amino acid/ammonium, tannin/anthocyanins and malic/tartaric acid. Additionally, severe pruning decreased tartaric acid, yield/meter trellis, ammonium % of YAN and Ravaz index. The findings presented in this thesis suggest that severe pruning could be used as a tool in viticultural areas with short growing seasons because of the increased ripening speed observed. However, because severe pruning generally increases berry size which is negative for vinification, it should be studied further with irrigation and management practices that decrease berry size.
38

Influence de la date de vendange sur les composés phénoliques de la baie de raisin : conséquences pour la typicité du vin / Influence of the harvest date on the phenolic compounds of the grape berries : consequences for the wines typicality

Cadot, Yves 08 December 2010 (has links)
L'objectif de la thèse est de contribuer à l'explicitation du lien au terroir, dans le cas de vins d'Appellation d'Origine Contrôlée. À ce lien au terroir correspond une typicité, qui correspond à des propriétés remarquables et partagées pour un groupe humain de référence. Le lien causal entre typicité et terroir a été étudié en prenant comme élément d'étude le chantier de vendange et les vinifications associées. La composition phénolique des vendanges, et leur aptitude à être extraits lors de la vinification ont permis de mieux interpréter le lien causal étudié. La représentation conceptuelle de la typicité, qui engendre des choix techniques, a été mise en évidence, du point de vue des critères sensoriels d'appartenance et des critères sensoriels de distinction. Cette représentation conceptuelle est en générale consensuelle, et les principaux facteurs du terroir, explicatifs du lien, correspondent au milieu physique. La représentation perceptuelle a été étudiée, permettant de mettre en évidence des descripteurs d'appartenance et de distinction, et de les hiérarchiser vis à vis de la perception globale de la typicité. Cette représentation est moins consensuelle. Les principaux facteurs du terroir, explicatifs du lien, correspondent aux actes techniques, en particulier la date de vendanges et la durée de cuvaison.Une évolution de la composition de la vendange en fonction du niveau de maturité a été mise en évidence d'un point de vue histologique, mais son interprétation est incomplète. L'aptitude des proanthocyanidines à être extraits, en fonction du niveau de maturité des baies est fortement corrélé à la perception globale de la typicité. Dans le cas de vins revendiquant un lien au terroir, certaines représentations de la typicité sont partagées, et engendrent des choix techniques (date de vendange, durée de cuvaison). L'importance de ces choix peut être démontré par l'étude de la composition de la vendange en composés phénoliques. Cependant, il existe un écart entre la typicité en tant que concept et la typicité telle qu'elle est sensoriellement perçue. / The aim of this work is to contribute to highlight the terroir effect, in the case of wines from delimited origin. The typicality is the result of the terroir effect and corresponds, to remarkable and shared properties for a human group of reference. The causal link between typicality and terroir was studied by taking into account the harvest date and the associated wine makings. The phenolic composition of the grape at harvest, and their extractability during the wine making made it possible to better interpret the studied causal link. The conceptual representation of the typicality, which generates technical choices, was highlighted, from the point of view of the sensory criteria of similarity and of distinction. This conceptual representation is in general consensual, and the main factors of the terroir, which explain the causal link, correspond to the soil and climate. The perceptual representation was studied, descriptors of similarity and distinction were highlighted, and theses descriptors were organized with respect to the global perception of the typicality. This representation is less consensual than conceptual one. The main factors of the terroir, which explain the causal link, correspond to the technical acts, particularly the harvest date and the vatting duration.Composition of the harvest, according to the level of maturity was highlighted from a histological point of view, but its interpretation was unfinished. The aptitude of the proanthocyanidins for being extracted, according to the level of maturity is strongly correlated for the global perception of the typicality. For wines related to terroir, some typicality representations are shared, and lead to technical choices (harvest date, duration of vatting). These choices are explained by the harvest composition. However, there is a difference between the typicality as a concept and the typicality as sensory perception.
39

Développements méthodologiques en chromatographie de partage : application aux stilbénoïdes / Methodological development in centrifugal partition chromatography : application to stilbenoids

Bisson, Jonathan 20 December 2012 (has links)
Les stilbénoïdes, sont des composés phénoliques majoritairement issus du règne végétal. La Vigne par l’intermédiaire du vin et du raisin est la principale source alimentaire de stilbènes. La mise en évidence de leur rôle dans les mécanismes de défense des plantes et leurs activités biologiques, y compris sur l’Homme, en font un sujet d’étude en plein essor. L’un des objectifs de cette thèse a été de développer un ensemble de stratégies à la fois analytiques et préparatives utilisant la Chromatographie de Partage Centrifuge (CPC) pour l’étude et l’obtention de ces molécules. Dans un premier temps, nous avons développé une approche de couplage entre cette technique et un spectromètre à Résonance Magnétique Nucléaire (RMN) par l’intermédiaire d’un système d’Extraction sur Phase Solide automatisé (EPS). Dans un second temps, nous avons mis au point un ensemble de méthodes et d’approches séparatives permettant d’obtenir ces composés. Nous avons, grâce au développement d’une méthodologie de dosage de solvants par spectrométrie RMN, étudié une gamme dérivée d’une gamme très utilisée en CPC, l’ARIZONA. Nous avons montré que ces systèmes dérivés, peuvent être utilisés au travers de stratégies d’élution telles que des pas et des gradients afin d’optimiser les séparations. L’une des finalités de notre travail est d’offrir des méthodes permettant d’obtenir ces composés dans des quantités et des qualités suffisantes pour pouvoir constituer une chimiothèque interne au laboratoire pouvant prétendre à s’intégrer dans la Chimiothèque Nationale. Une dernière partie fait état du développement d’outils informatiques, dont la création d’une base de donnée Libre pour les chercheurs en Substances Naturelles. / Stilbenoids are phenolic compounds mostly found in the vegetable kingdom. Vine through wine and grape is the main source of stilbenes in the human diet. The involvement of these compounds in plants resistance mechanisms and their diverse biological activities, including on the human health are continuously highlighted. Making this topic a fast-growing one. One of the objectives of this thesis has been to develop a whole set of analytical and preparative strategies using Centrifugal Partition Chromatography (CPC) in order to study and obtain these molecules. Over a first phase, we developed a hyphenated approach between this technique and Nuclear Magnetic Resonance (NMR) through an automated Solid Phase Extraction (SPE) system. Then, we developed a set of separative methods and approaches with the aim of obtaining these compounds. Then, we carried out the development of a solvent quantifications methodology using NMR spectrometry. This allowed us to study a spin-off scale of a widely-used solvent systems collection called ARIZONA. We showed that these systems are good candidates for different elution strategies using steps and gradients with the aim to optimize separations. One of our purpose was to provide methods for effective and efficient purification of these compounds. This would allow, together with a lab-scale compounds library, their integration into the Chimiothèque Nationale, a nationwide chemical library. Last part accounts for computer tools development, including the creation of a Free database system for Natural Substances researcher.
40

Fosfito de potássio no controle de doenças pós-colheita em bagas de uva ´Itália´ e possíveis mecanismos de ação à Rhizopus stolonifer / Potassium phosphite on postharvest disease control in ´Itália´ grape berries and possible mode of action to Rhizopus stolonifer

Roma, Rafaela Carolina Constantino 10 March 2014 (has links)
A ocorrência de doenças em uvas de mesa gera perdas desde o cultivo até a comercialização, o que afeta diretamente o potencial de exportação do Brasil. A prevenção na realização de injúrias nos frutos é essencial para garantir a eficácia dos tratamentos aplicados tanto em pré- quanto em pós-colheita. Visando o emprego de produtos alternativos que auxiliem no manejo sustentável da cultura, o fosfito de potássio encontra-se como ferramenta útil. O efeito do fosfito no controle de doenças causadas por oomicetos já foi relatado, porém, como este ingrediente ativo atua sobre microrganismos do reino Fungi ainda é desconhecido. Neste contexto, este trabalho teve como objetivo avaliar o fosfito de potássio no controle das doenças podridão mole, mofo cinzento e podridão da uva madura, causadas por Rhizopus stolonifer, Botrytis cinerea e Colletotrichum gloeosporioides, respectivamente, em bagas de uva ´Itália´ e seus efeitos na qualidade físico-química dos frutos. Também objetivou-se estudar os mecanismos de ação envolvidos na inibição do desenvolvimento do micélio de R. stolonifer na presença do produto e na indução de respostas de defesa em bagas de uva. Foram realizados ensaios in vitro para avaliação do efeito do fosfito sobre o crescimento micelial, esporulação e germinação dos esporos para R. stolonifer, B. cinerea e C. gloeosporioides. Experimentos utilizando-se de bagas foram conduzidos, visando avaliar o efeito no uso do fosfito como fungicida produtor ou curativo para os três patógenos. Cachos foram utilizados para se determinar os efeitos da aspersão do fosfito sobre a qualidade físico-química dos frutos. Para avaliação dos mecanismos de ação do fosfito sobre o micélio de R. stolonifer, foram determinados os efeitos sobre a permeabilidade da membrana plasmática, a síntese de parede celular e a síntese de proteínas. A atividade de guaiacol peroxidase e de compostos fenólicos totais foi determinada em bagas de uva tratadas ou não com fosfito. Houve inibição do crescimento micelial, da esporulação e da germinação dos esporos dos patógenos desenvolvidos em diferentes concentrações de fosfito de potássio. O tratamento protetor e curativo das bagas evidenciou reduções significativas na área abaixo da curva de progresso das doenças estudadas. Não houve efeito do produto sobre a qualidade físico-química dos cachos de uva. Quanto aos mecanismos de ação, foram observados efeitos do fosfito sobre a permeabilidade de membrana, devido à elevada perda de eletrólitos do micélio. O fosfito proporcionou elevação na síntese de proteínas totais no micélio do patógeno e redução na atividade de ?-1,3- glucanase e quitinase, que são enzimas relacionadas à síntese de parede. A atividade de guaiacol peroxidase e a concentração de compostos fenólicos totais não aumentou com a aplicação do fosfito nas bagas. Desta forma, pode-se concluir que o fosfito de potássio controlou a podridão mole, o mofo cinzento e a podridão da uva madura e não teve efeito sobre a qualidade físico-química dos frutos. Ainda, o fosfito atuou sobre a permeabilidade de membrana, síntese de proteínas e de parede celular do micélio de R. stolonifer e não proporcionou indução da atividade de guaiacol peroxidase e compostos fenólicos totais em bagas de uva. / The occurrence of table grape diseases causes losses from the field to the commercialization, which affects the Brazil potential to export. The prevention of injuries in fruits is essential to ensure the pre- and postharvest treatment efficiency. In order to use alternative products to support the crop sustainable management, phosphite may be a useful tool. The phosphite effect on control of diseases caused by oomycetes has been reported, however, how the active ingredient acts on microorganisms from the Fungi kingdom is unknown. Thus, the objective was to evaluate potassium phosphite on the control of soft rot, grey mold and ripe rot, caused by Rhizopus stolonifer, Botrytis cinerea e Colletotrichum gloeosporioides, respectively, in ´Itália´ grape berries and its effect on physico-chemical properties of the fruits. Moreover, the objective was to study the mode of action involved on the inhibition of R. stolonifer grown in the presence of phosphite and on the induction of defense responses in grape berries. In vitro assays were carried out to evaluate the effect of phosphite on mycelial growth, sporulation and spore germination in R. stolonifer, B. cinerea e C. gloeosporioides. Single berries were used in order to evaluate the effect of phosphite as a protective or curative fungicide against the three pathogens. Grape clusters were used to determine the effects of phosphite spraying on physico-chemical properties. To evaluate the mode of action of phosphite on R. stolonifer mycelium the plasma membrane permeability, the protein synthesis and the cell wall synthesis were monitored. The guaiacol peroxidase activity and phenolic compound concentration were evaluated in grape berries treated or not with phosphite. There were inhibition on mycelial growth, sporulation and spore germination on the three pathogens in different potassium phosphite concentrations. The protective and curative treatment in grape berries showed significant reductions on the area under disease progress curve of the studied diseases. There was no effect on physico-chemical properties of the grapes. Regarding the mode of action, the phosphite affected membrane permeability what was seen as high electrolyte leakage from the mycelium. Phosphite caused high protein synthesis in the mycelium and reduction on ?-1,3-glucanase and chitinase activities, which are enzymes related to cell wall synthesis. The guaiacol peroxidase activity and phenolic compound concentration did not increase due the phosphite application. Thus, it may be concluded that potassium phosphite controlled soft rot, grey mold and ripe rot in grape berries and did not affect the physico-chemical properties of the fruits. Besides that, phosphite still acted on membrane permeability, protein synthesis and cell wall synthesis on the R. stolonifer mycelium and did not changes in guaiacol peroxidase activity and phenolic compound concentration in the grape berries.

Page generated in 0.1113 seconds