Thesis (M.A.)--University of Northern Iowa, 2007. / Also available via the World Wide Web. Includes bibliographical references (leaves 53-58).

Mémoire (M.Ress.Renouv.)--Université du Québec à Chicoutimi, 1999. / Document électronique également accessible en format PDF. CaQCU

From samples of stained yellow cedar wood, Chamaecyparis nootkatens is (D. Don) Spach, collected at three different localities on the British Columbia coast, isolation studies consistently yielded two members of the group Fungi Imperfecti. Reinoculation of these fungi into sound wood produced black stain similar to that found in nature. In addition to these Deuteromycetes, three basidiomycetous fungi, Poria weirii Murr, Poria asiatica (Pilát) Overholts and Xeromphalina campanella (Batsch. ex Fr.) Kühner and Maire, were isolated. Of these the Poria species are believed to be first records for the host. Studies on Petri plates revealed no marked antagonism between the two Deuteromycetes and P. weirii. The two deuteromycetous fungi gave positive reactions on gallic and tannic acid agars, demonstrating the production of the enzyme extracellular oxidase. Two series of yellow cedar beams were respectively inoculated with macerated cultures of the Deuteromycetes by means of a special technique described. This technique produced exceptionally rapid and uniform fungal growth in comparison to that obtained under standard cultural conditions. Inoculated beams were subjected to weight and strength loss tests, in comparison to control beams. Weight losses of 0.17 percent and 8.40 percent respectively were noted for the two fungi. No significant difference in impact modulus of rupture values was detected between test and control for either fungus. Significance of experimental results is briefly discussed and recommendations for further study suggested. / Science, Faculty of / Botany, Department of / Zoology, Department of / Graduate

Drought resistance among genotypes of Port-Orford-cedar (Chamaecyparis lawsoniana (A. Murr.) Pan., Cupressaceae) seedlings was evaluated both in the field and in the greenhouse. Field water potentials (��) of 5-year-old seedlings were measured at two high-elevation plantation sites where summer drought occurs. Measurements of �� were compared to survival two years prior at the same site. The north coastal breeding zone 1 had significantly lower mid-day �� and lower survival than the southern interior breeding zone 6. Percent survival at 3 years was significantly correlated with mid-day ��. A second assessment of drought resistance was performed in the greenhouse on 1-0 seedlings. Root growth potential (RGP) was measured in the winter under non-stress conditions and following a drought in the summer. Differences among breeding zones were opposite in pattern from outplanting measurements of survival and water potential; therefore, RGP may not be a good predictor of drought resistance or survival among different genotypes within a single species. Low-elevation, coastal families had greater root growth than inland, high elevation sources. Greater root growth occurred in seedlings with more shoot mass. Little regional specialization in RGP across the species' range was indicated as there was greater variation among families than among breeding zones. In the summer RGP test following drought, only the two extremes of the range were evaluated; both north coastal and southern interior families showed decreased root growth compared to the winter RGP under non-stress conditions. Despite significantly higher predawn �� in inland, high elevation families, lower elevation coastal families had significantly more roots. Change in chlorophyll fluorescence yield measured on foliage of droughted plants was positively correlated with the absolute value of predawn ��; however, it was not a sensitive predictor of predawn �� (R��=0.06) at the levels used in this study. Lower levels of �� may be necessary to produce severe stress to damage Port-Orford-cedar foliage. / Graduation date: 2003

Thesis (D. Min.)--Trinity International University, 2003. / Abstract. Includes bibliographical references (leaves 152-155).

Thesis (D. Min.)--Trinity International University, 2003. / Abstract. Includes bibliographical references (leaves 152-155).

Breeding Port-Orford-cedar for resistance to Phytophthora lateralis, a causal agent of root disease, begins by screening, through artificial inoculation, phenotypically resistant trees selected from natural stands. The successful program selected tolerant or resistant POC parent trees for the purpose of disease management. Candidate resistant POCs were used in my dissertation to: 1. validate screening methods such as stem- and root-dip inoculation; 2. test for increased virulence of P. lateralis; and 3. evaluate detection techniques. The results showed that the established screening methods were appropriate, and no evidence of changed virulence was found. A PCR technique was more reliable than other techniques for detection of P. lateralis in seedlings. An additional test for foliar infection showed that initial penetration through wounds and natural openings was possible. POC seedlings and rooted cuttings from resistant and susceptible families were used to demonstrate resistance mechanisms. In order to explain the mechanisms at the cellular level, the susceptible response of POC seedlings to P. lateralis was first observed with light microscopy. Zoospores encysted on lateral roots, germinated, and penetrated by means of appressoria. Direct penetration between epidermal cells was common but penetration through epidermal cell walls was also observed. The hyphae colonized the root cortex inter- and intracellularly. Wound inoculation on stems resulted in inter- and intra cellular hyphal growth in cambial, sieve, and parenchyma cells in the secondary phloem. Several resistance mechanisms were observed: 1) there was a difference in zoospore attraction between susceptible and certain resistant POCs revealed by microscopic observation, direct count of encysted zoospores, and quantitative real-time PCR; 2) the frequency of encystment, penetration, and colonization of resistant seedlings was much lower than susceptible seedlings, but no differences in infection pathway were observed by means of light or electron microscopy; 3) collapsed cell walls were present in resistant POCs showing increased cell wall thickness, wall appositions, and electron dense materials. / Graduation date: 2005

Everything falls apart, but some materials do it with a specific panache, and once design leaves paper to be built, no project is complete until it falls. As creatures subject to time, we identify with things in which we see ourselves, we identify with our mortal buildings. Alchemy used material transformation as an active metaphor for human betterment. This thesis will search for ways that the inevitable indexing of time on the built environment can be used to catalyze a broader understanding of time and our place in it. Sympathetic engagement with our environments can form rich internal narratives while also fostering collective memory. Four materials form the basis of these investigations: Cedar, Copper, Iron and Marble. For each material, chemical properties, history and mythology are invoked to describe their particular temporal nature, an understanding of how they come together and fall apart. The four material chapters of this thesis mean to return a sense of cognitive depth to our relationship with materials without resorting to symbolism.

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Everything falls apart, but some materials do it with a specific panache, and once design leaves paper to be built, no project is complete until it falls. As creatures subject to time, we identify with things in which we see ourselves, we identify with our mortal buildings. Alchemy used material transformation as an active metaphor for human betterment. This thesis will search for ways that the inevitable indexing of time on the built environment can be used to catalyze a broader understanding of time and our place in it. Sympathetic engagement with our environments can form rich internal narratives while also fostering collective memory. Four materials form the basis of these investigations: Cedar, Copper, Iron and Marble. For each material, chemical properties, history and mythology are invoked to describe their particular temporal nature, an understanding of how they come together and fall apart. The four material chapters of this thesis mean to return a sense of cognitive depth to our relationship with materials without resorting to symbolism.