Thesis (M. For. Sc.)--University of Canterbury, 2006. / Typescript (photocopy). "August 2006." Includes bibliographical references (leaves 101-114). Also available via the World Wide Web.

O objetivo do presente trabalho foi encontrar novas espécies para o segmento de Madeira Laminada Colada e substituir adesivos tradicionais que emitem compostos voláteis tidos na literatura como não amigáveis ao meio ambiente. Foram caracterizadas as espécies Hevea brasiliensis (Seringueira), C. maculata (Maculata) e C. lusitanica (Cupressus) e sintetizado um poliuretano à base de óleo de mamona, sem solventes e aditivos, que foi utilizado na fabricação de corpos de prova para ensaios de cisalhamento. A resistência ao cisalhamento paralela às fibras foi a variável trabalhada para caracterizar as espécies e validar o poliuretano. O processo de produção desse poliuretano iniciou-se com as sementes de mamona produzidas, seguiu na extração à frio do óleo que foi comparado com um óleo comercial e culminou na síntese do poliuretano. O óleo comercial possibilitou a obtenção do melhor poliuretano devido a sua pureza. Não foram encontradas diferenças na aplicação do poliuretano quando aplicados em uma ou nas duas faces de contato a serem unidas nos corpos de prova das três espécies, vantagem do poliuretano que representa redução de custo na MLC. O poliuretano de mamona produzido em laboratório com óleo comercial superou o adesivo resorcinolformaldeído no que se refere à resistência ao cisalhamento da madeira de Cupressus e foi similar quando comparado à Seringueira. Seringueira e Cupressus mostraram-se aptas para a produção de madeira laminada colada, superando o Maculata em termos de qualidade mecânica. / The aim of this study was to indentify new species for the segment of glued laminated timber (glulam) and replace traditional adhesives that emit volatile compounds, reported in literature taken as unfriendly to the environment. We characterized species Hevea brasiliensis (Rubberwood), C. maculata (Maculata) and C. lusitanica (Cupressus). We synthesized castor oil-based polyurethane without additives and solvents, used in shear strength tests. The shear strength parallel to grain was the worked variable to characterize and validate the polyurethane species. The manufacturing process of polyurethane started with the production of castor oil seeds, followed by cold extraction of oil, which was compared with commercial oil, and the process culminated with the polyurethane synthesis. The commercial oil provided better polyurethane due to its purity. There were no differences in the polyurethane application in one or two of the contact faces to be joined in the manufacture process for wood test specimens of the three species, one advantage of polyurethane is cost reduction of the glulam. The castor oil-based polyurethane produced in the laboratory outperformed the commercial resorcinol-formaldehyde adhesive in terms of wood shear strength tests for Cupressus and was similar when in Rubberwood. Rubberwood and Cupressus proved suitable for the production of glulam, surpassing Maculata in terms of mechanical quality.

O objetivo do presente trabalho foi encontrar novas espécies para o segmento de Madeira Laminada Colada e substituir adesivos tradicionais que emitem compostos voláteis tidos na literatura como não amigáveis ao meio ambiente. Foram caracterizadas as espécies Hevea brasiliensis (Seringueira), C. maculata (Maculata) e C. lusitanica (Cupressus) e sintetizado um poliuretano à base de óleo de mamona, sem solventes e aditivos, que foi utilizado na fabricação de corpos de prova para ensaios de cisalhamento. A resistência ao cisalhamento paralela às fibras foi a variável trabalhada para caracterizar as espécies e validar o poliuretano. O processo de produção desse poliuretano iniciou-se com as sementes de mamona produzidas, seguiu na extração à frio do óleo que foi comparado com um óleo comercial e culminou na síntese do poliuretano. O óleo comercial possibilitou a obtenção do melhor poliuretano devido a sua pureza. Não foram encontradas diferenças na aplicação do poliuretano quando aplicados em uma ou nas duas faces de contato a serem unidas nos corpos de prova das três espécies, vantagem do poliuretano que representa redução de custo na MLC. O poliuretano de mamona produzido em laboratório com óleo comercial superou o adesivo resorcinolformaldeído no que se refere à resistência ao cisalhamento da madeira de Cupressus e foi similar quando comparado à Seringueira. Seringueira e Cupressus mostraram-se aptas para a produção de madeira laminada colada, superando o Maculata em termos de qualidade mecânica. / The aim of this study was to indentify new species for the segment of glued laminated timber (glulam) and replace traditional adhesives that emit volatile compounds, reported in literature taken as unfriendly to the environment. We characterized species Hevea brasiliensis (Rubberwood), C. maculata (Maculata) and C. lusitanica (Cupressus). We synthesized castor oil-based polyurethane without additives and solvents, used in shear strength tests. The shear strength parallel to grain was the worked variable to characterize and validate the polyurethane species. The manufacturing process of polyurethane started with the production of castor oil seeds, followed by cold extraction of oil, which was compared with commercial oil, and the process culminated with the polyurethane synthesis. The commercial oil provided better polyurethane due to its purity. There were no differences in the polyurethane application in one or two of the contact faces to be joined in the manufacture process for wood test specimens of the three species, one advantage of polyurethane is cost reduction of the glulam. The castor oil-based polyurethane produced in the laboratory outperformed the commercial resorcinol-formaldehyde adhesive in terms of wood shear strength tests for Cupressus and was similar when in Rubberwood. Rubberwood and Cupressus proved suitable for the production of glulam, surpassing Maculata in terms of mechanical quality.

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Made available in DSpace on 2016-06-02T20:36:22Z (GMT). No. of bitstreams: 1 2421.pdf: 6588064 bytes, checksum: 002b104af419727d81cefcf85c47c6dd (MD5) Previous issue date: 2009-02-12 / Universidade Federal de Sao Carlos / Some phytopatogenic fungi found in Cupressus species produces phytotoxins very aggressive to the host plant. Surprisingly, these toxins are diterpenoids structures, as well as some endogenus metabolites in Cupressus species. This fungi ability appears to be a specialized strategy in the association fungi-plant. These observations motivated the development of the present work, which relates the isolation of microorganisms associated to the species Cupressus lusitanica, and to its study, aiming a correlation of the chemical profile among the organisms involved in this association. During two collects of plant material from an exemplar found in the campus of the UFSCar, five endophytic fungi had been isolated and called NICL1-5. A preliminary identification indicated that possibly four of them belong to the Xylaria genus, and one to the Guignardia genus (NICL4). The analysis with GC-MS had detected three isocoumarins (mellein, mellein methyl ether, 5- formylmellein), as well as an eremophilane sesquiterpene (valencene) in extracts of NICL3 fungi. From the extracts of the same fungi, had been obtained three eremophilanes sesquiterpenes (two news in literature) by the use of classical methodologies of chromatography. These compounds had been identified using a series of NMR data in 1D and 2D. From the study of the secondary metabolites of NICL5 had been obtained ergosterol, sorbitol and three cytochalasins (cytochalasin C, cytochalasin D and cytochalasin Q). The metabolism if NICL5 had also been studied, when free amino acids were added in the culture medium. By the analysis with HPLC-MS significant alterations in the NICL5 metabolism had been detected, as a possible induction of the biosynthesis of a new cytochalasin, from the amino acid tryptofane. The analysis of the plant material indicated the presence of biflavonoids and some diterpenes. However, these compounds had not been detected in fungi extracts, being identified only sesquiterpenes. / Alguns fungos fitopatogênicos a Cupressus produzem fitotoxinas bastante agressivas à hospedeira. Surpreendentemente, essas fitotoxinas são, em geral, de estruturas diterpenoídicas, assim como vários metabólitos endógenos nas espécies de Cupressus. Essa habilidade mostrada pelo fungo parece ser uma estratégia bastante especializada de associação fungo-planta. Essas observações motivaram o desenvolvimento do presente trabalho, o qual se refere ao isolamento de microrganismos associados à espécie Cupressus lusitanica, e o seu estudo visando uma correlação do perfil químico entre os organismos envolvidos nessa associação. Durante duas coletas de material vegetal a partir de um indivíduo encontrado no campus da UFSCar, foram isolados cinco fungos endofíticos, denominados NICL1-5. Identificação preliminar indicou que possivelmente quatro deles pertencem ao gênero Xylaria e um ao gênero Guignardia (NICL4). Através de análises por CG-EM, detectouse três isocumarinas (meleína, éter metílico da meleína e 5-formil meleina), bem como um sesquiterpeno eremofilano (valenceno) em extratos do fungo NICL3. Dos extratos deste mesmo fungo, foram obtidos três sesquiterpenos eremofilanos (sendo dois novos na literatura), usando metodologias clássicas de cromatografia. Esses sesquiterpenos foram identificados usando uma série de dados de RMN em 1D e 2D. Do estudo dos metabólitos secundários de NICL5 foram obtidos o ergosterol, o sorbitol e três citocalasinas (citocalasina C, citocalasina D e citocalasina Q). Foi estudado também o metabolismo de NICL5 frente à adição de aminoácidos livres ao meio de cultura. Usando análises por CLAE-EM, detectaram-se significantes alterações no metabolismo de NICL5, como uma possível indução da biossíntese de uma nova citocalasina, a partir do aminoácido triptofano. As análises do material vegetal indicaram a presença de biflavonóides e vários diterpenos. Porém, esses compostos não foram detectados nos extratos fúngicos, sendo identificados apenas sesquiterpenos.

No description available.

Une entité botanique peut être considérée comme une succession ordonnée d'entités botaniques d'un niveau d'organisation inférieur (ex : une unité de croissance peut se décrire comme une succession de métamères). Pour chaque entité botanique, il est possible de mesurer un certain nombre de variables qui traduisent ses caractéristiques (longueur de l'entre-nœud, type de production axillaire). La succession des valeurs prises par une ou plusieurs variables mesurées est alors appelée « séquence d'événements botaniques ». Des travaux récents menés chez des arbres fruitiers et forestiers ont permis de développer une approche statistique adaptée à l'analyse d'échantillons de séquences allant de l'analyse exploratoire à la construction de processus Markoviens. L'objectif de cette thèse est (i) d'évaluer la pertinence d'une approche couplant analyse architecturale et analyse de séquences extraites d'architectures mesurées, (ii) d'apporter une vision et une compréhension nouvelle des phénomènes de croissance, de ramification et de floraison par l'utilisation de modèles statistiques adaptés et (iii) d'analyser les applications possibles des comparaisons de séquences et de modèles dans l'étude de l'influence du milieu et la caractérisation de la plasticité architecturale. Cette problématique est illustrée par (i) l'étude des structures de ramification des différents types d'unités de croissance des pousses annuelles mono- ou polycycliques de chêne rouge d'Amérique (Quercus rubra), (ii) des synchronismes de ramification et de floraison chez Cecropia obtusa et (iii) par l'étude de l'évolution de la phyllotaxie et des modalités de ramification au cours de l'ontogénie sur plusieurs espèces de Cupressus. Les résultats montrent que la répartition des productions axillaires sur une entité porteuse n'est pas aléatoire mais qu'elle est le plus souvent organisée en une succession de zones homogènes ou montre des motifs répétés à un niveau plus local. Les mécanismes sous-jacents potentiellement responsables des organisations révélées à diverses échelles et l'apport de la prise en compte de l'information structurelle des arbres dans la mesure et l'analyse statistique des données sont discutés

The increased soil organic phosphorus (P) mineralization observed under trees compared to pasture has been attributed to the contrasting mycorrhizal associations of the two systems but to date, little work has been conducted comparing P dynamics under different tree species with contrasting mycorrhizal associations. This study investigated rhizosphere P dynamics and P acquisition of three tree species with contrasting mycorrhizal associations (ectomycorrhizal Pinus radiata, arbuscular mycorrhizal Cupressus macrocarpa and tripartite Ecualyptus nitens) using a combination of field and controlled environment studies. Short-term field studies revealed greater acid phosphomonoesterase activity and therefore greater potential organic P mineralization under radiata pine and eucalypt compared with macrocarpa, which correlated with ectomycorrhizal colonization. Related field work revealed that the presence of pasture understory and litter had a significant impact on P dynamics. Pasture acts to increase phosphatase activity and microbial activity within the soil but with a litter layer, the increased activities are mainly above the soil in the overlying litter. A glasshouse study investigated the separate influence of mycorrhizal hyphae and roots and results showed that ectomycorrhizal fungi associated with radiata pine and eucalypt stimulated microbial activity and increased rhizosphere phosphatase activity with a concomitant decline in soil organic P. Macrocarpa and eucalypt roots exuded higher concentrations of low molecular weight organic anions compared with radiata pine which stimulated microbial activity, increased rhizosphere phosphatase activity and decreased soil organic P. A series of experiments were then conducted to further investigate the precise role of mycorrhizae in P dynamics and results showed that ectomycorrhizal colonization increased rhizosphere acid phosphomonoesterase to a greater extent than arbuscular mycorrhizae. Fluorescent staining revealed that the mycorrhizae associated with all three species had similar phosphatase production capacities. The ability of the three species to utilize organic P was investigated in two exhaustive pot experiments. Radiata pine was shown to be the best adapted to utilize organic P, especially in soils with high relative organic P contents. Eucalypt appeared to enhance soil organic P mineralization but did not take up the released inorganic P, while macrocarpa caused limited organic P mineralization compared with radiata pine and eucalypt. This work shows that ectomycorrhizal trees are best adapted to utilize organic P through increased rhizosphere phosphatase activity and stimulated microbial activity. Root exudation of LMWOAs is of higher relative importance to arbuscular mycorrhizal trees to increase microbial activity and consequently phosphatase activities when fewer hyphae are in the rhizosphere are present to produce them.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.

Cette étude a pour objectif d'une part, de développer une méthode d'analyse des huiles essentielles basée sur la combinaison du couplage CPG/SM et de la RMN du carbone-13, avec ou sans fractionnement, en utilisant les données de la littérature, en reconstruisant les spectres de molécules absentes de nos bibliothèques et d'autre part, de contribuer à une meilleure connaissance de l'huile essentielle de diverses plantes de Madagascar, endémiques ou introduites, en les caractérisant et en décrivant une éventuelle variabilité chimique. Ces analyses nous ont permis d'identifier efficacement des composés délicats à analyser par les techniques conventionnelles (stéréoisomères, molécules thermosensibles). Nous avons également étudié six échantillons de Cedrelopsis grevei et réalisé un fractionnement poussé de l'un d'entre eux, ce qui nous a permis d'identifier de très nombreux sesquiterpènes. Enfin, nous avons montré la variabilité interspécifique des huiles essentielles du genre Helichrysum.