Thesis (doctoral)--Eidgenössischen Technischen Hochschule in Zürich, 1965. / Reprint of Ber. geobot. Inst. ETH, Stiftg. Rübel, Zürich 36, 28-102 (1965). Abstract also in German. Cover title. Includes bibliographical references (p. 92-94).

Thesis (M.Sc.)--Acadia University, 2001. / Includes bibliographical references (leaves 42-51). Also available on the Internet via the World Wide Web.

Thesis (M.S.)--Oregon State University, 1993. / Typescript (photocopy). Includes bibliographical references (leaves 144-148). Also available on the World Wide Web.

The time dependent molecular motions of wood components at straining parallel to fibre direction were observed by infrared polarization technique. A two-stage molecular motion involving three wood components, cellulose, hemicellulose and lignin is suggested as the course of wood molecular relaxation. The first stage begins at equilibrium, when the specimen is not stressed, and extends immediately to a minimum dichroic ratio (formula omitted) of carbo-hydrate components represented by 1160 cm⁻¹ and 1730 cm⁻¹ bands, and the maximum dichroism of lignin (1500 cm⁻¹). The second stage starts at the end of the first stage and extends to equilibrium recovery. Regardless of the form of external excitation (creep or stress relaxation), and the time of excitation (ramp- or step-loading), the basic pattern of the two-stage molecular motion was followed, while damping of the molecules accompanied the whole rheological process. Thus, the wood macromolecular structure maintains an "internal state" of equilibrium on receiving external excitation. This equilibrium state is achieved by moving the carbohydrate and lignin components in opposite directions. The described pattern of molecular motion for a component in wood is a compensatory result from the interference of other components. Removing one or more components from wood changes the motion patterns of the remaining components. The conformation of cellulose in the specimen without the presence of lignin and hemicellulose is comparable to that of other synthetic linear polymers. Energy transfer system of wood was postulated as being due to the directional movement of molecular components which results in association and high steric interference between carbohydrates and lignin, similar to cross-linked chains of lignin and carbohydrates. This energy transfer system of wood is further facilitated by the existence of a systematic structure of wood microfibrils which permits a zone of gradual transition from high crystallinity to a diffuse state. The lignin network of the system may do more than transfer energy, it may act also as an "energy sink" and thereby function to maintain the memory of the excitation. / Forestry, Faculty of / Graduate

The absence of the majority of conifers from tropical forests remains an unresolved evolutionary and biogeographic enigma. Correlations between a flattened conifer leaf morphology and tropical persistence have led to the hypothesis that shade tolerance is critical for conifer survival in these environments. Yet, little is known of the physiological mechanisms constraining conifer distributions. This dissertation, using the diversity of leaf morphologies and biogeographic distributions found among conifer families, examines this hypothesis from a physiological perspective. The first chapter examines the photosynthetic process in shade-house grown saplings of conifers coexisting in the Central Highlands of Vietnam, an area of unusual tropical conifer diversity. Pinus krempfii, a flat-leaved pine endemic to the densely-canopied tropical forests of Vietnam, demonstrates an intermediate photosynthesis between needle-leaved Pinus and flat-leaved Podocarpaceae, thus providing support for shade tolerance as an important driver of conifer success in tropical forests. In chapter two, respiratory traits are examined in adult conifers growing naturally in the Central Highlands of Vietnam. Flat-leaved conifer species are found to have lower respiration than needle-leaved species. Finally, in chapter 3, the respiratory temperature responses of members from the two largest conifer families, the Pinaceae and Podocarpaceae, are compared. Consistently lower respiration in Podocarpaceae compared to Pinaceae suggests that there are phylogenetic underpinnings to the respiratory differences between the two families. These findings correlate to the biogeographic differences between the two families, with Podocarpaceae being notably more successful in tropical forests than Pinaceae. Together, all three chapters demonstrate that lower foliar carbon fluxes and flattened leaf morphologies are characteristics of a shade tolerance strategy that is necessary for conifer persistence in tropical forests. Ultimately, this dissertation makes a unique link between conifer physiologies and their current biogeographic distributions that will pave the way for a mechanistic tackling of their future survival in a changing climate.

No description available.

The Suillus mycota of Nepal was studied. Nine species are recognized and described; five of the nine appear to be new species. Additional species were collected, but material was inadequate to describe them completely. Cultures of eight and synthesized ectomycorrhizae of six of the Suillus species are described. Synoptic keys to the basidiocarps and to the cultures are presented. Numerical taxonomic analyses of the cultures generated clusters which paralleled the species concepts developed using basidiocarps and ecology. Each species of Suillus from Nepal is host specific based on basidiocarp formation; all hosts are in the Pinaceae. Field associations are Suillus cf. granulatus, S. cf. placidus, S. sibiricus, and greening-foot Suillus with Pinus wallichiana; queen's Suillus with P. roxburghii; waxy Suillus with P. patula; and S. laricinus, himalayan Suillus, and orange-pored Suillus with Larix himalaica. Mycorrhizal syntheses confirmed that the six Suillus-Pinus relationships are ectomycorrhizal. The Suillus mycota of western Virginia has 12 known species. Three, of the five which are ectomycorrhizal with Pinus strobus, have closely related counterparts in Nepal. These counterparts are ectomycorrhizal with P. wallichiana, a five-needled pine closely related to P. strobus. The existence of these three pairs of similar fungi, associated with similar pines, suggests the possibility of cladogenic speciation in parallel by the pine lineage and by its ectomycorrhizal fungal associates. Boletinellus merulioides forms abundant sclerotia in nature throughout its range in eastern North America. Sclerotia collected in the forest germinated to form mycelial colonies that had the same appearance and microscopic characteristics as colonies derived from basidiocarps. Sclerotia which had overwintered in the forest were viable in the spring. The spatial pattern of B. merulioides sclerotia in a forest was compared with basidiocarp frequency recorded over four years. Both estimates of the spatial pattern coincided, but year-to-year basidiocarp frequency varied greatly. Individual B. merulioides dikaryons formed large perennial patches. Basidiocarp and sclerotial densities were centered around and declined outward from Fraxinus americana trees. Boletinellus merulioides and Fraxinus pennsylvanica did not form ectomycorrhizae when grown together in growth pouches. / Ph. D.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 104-113). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 1993. / Typescript (photocopy). Includes bibliographical references (leaves 40-50). Also available on the World Wide Web.

O presente trabalho teve como objetivo caracterizar o desenvolvimento da semente de Araucaria angustifolia através da proteômica comparativa, buscando compreender as alterações fisiológicas e metabólicas que ocorrem durante esse processo. Inicialmente, foram avaliados três diferentes metodologias de extração de proteínas. A metodologia composta por solução de extração contendo 7 M de uréia, 2 M de tiouréia, 1% de ditiotreitol, 2% de Triton-100, 1 mM de fluoreto de fenilmetilsulfonil e 5 µM de pepstatina, seguido de precipitação em 20% de ácido tricloroacético apresentou géis de maior resolução e reprodutibilidade, tendo sido escolhida como metodologia de extração protéica para o estudo das alterações no proteoma da semente de A. angustifolia. Uma dificuldade associada ao estudo do proteoma de espécies não sequenciadas é a baixa representatividade nos bancos de dados protéicos, resultando em identificações baseadas em homologia. Estratégias proteômicas baseadas em fracionamento em gel resultam em grandes contaminações por fragmentos de queratina. Sendo assim, foi desenvolvido um programa de remoção de espectros de baixa qualidade para utilização em proteômica baseada em homologia. As análises mostraram que o programa reduz o tempo de busca, melhora a qualidade dos alinhamentos e não resulta em perda de identificações positivas. Finalmente, utilizando as metodologias descritas, foram estudadas as alterações no proteoma durante o desenvolvimento da semente de A. angustifolia. Noventa e seis proteínas foram identificadas e agrupadas de acordo com sua função biológica e padrão de detecção. Os resultados obtidos permitiram o estabelecimento de marcadores protéicos no início e final do desenvolvimento embrionário. A análise das proteínas abundantes no início da embriogênese indica um maior controle no metabolismo oxidativo em relação aos estádios finais. Contrariamente, o final da embriogênese é caracterizado por um alto metabolismo de assimilação de carbono e acúmulo de proteínas de reserva. As implicações dos resultados obtidos no controle e melhoramento de sistemas de embriogênese somática na espécie também foram discutidas. / The aim of the present work was to characterize the seed development of Araucaria angustifolia through proteomics in order to understand the physiological and biochemical changes during this process. For that, initially, three different protein extraction methods were evaluated. The extraction based on protein solubilization in 7 M urea, 2 M thiourea, 1% dithiothreitol, 2% Triton-100, 1 mM phenylmethylsulphonyl fluoride, 5 µM pepstatin, followed by 20% trichloroacetic acid precipitation showed the highest gel resolution and reprodutivity and, thus, was chosen to be used in the analysis of the proteome of A. angustifolia seeds. One aspect that hampers the proteome study of unsequenced species is the low protein representativity in databases. So, protein identification is usually carried out through homology. Strategies based on 2-DE result in high keratin contamination. In the present work a spectra filtering software was developed and evaluated for use in homology driven proteomics. The software reduced the time of search, improved alignment quality and did not result in lost of positive identifications. Finally, using the described strategies, the changes in the proteome of A. angustifolia seeds were studied. Ninety six proteins were identified and classified according to their biological functions and expression profiles during seed development. The identified proteins may be used as protein markers of early and late embryogenesis. Proteins involved in the control of oxidative metabolism were highly expressed during the early stages of seed development; while, carbon metabolism and storage proteins were highly expressed in late stages. Considerations on the improvement and control of somatic embryogenesis through medium manipulation and protein markers screening using data generated are also discussed.