No description available.

[Truncated abstract] Eucalyptus occidentalis, a timber species from south Western Australia, is highly salt and waterlogging tolerant. Screening identified genotypes tolerant of high salt concentrations and waterlogging. Tolerance at provenance, family and individual level, and how phenotypic performance under salt and waterlogging was inherited was explored to provide a breeding population. Salt and/or waterlogged screening was carried out under controlled conditions up to extreme salt levels to determine tolerance between genotypes. This tank method was shown to produce repeatable results. Seedlings of 30 families from 9 provenances were used for screening. At low salt concentration (up to 300 mM NaCl), differentiation occurred for some traits but in general there was only a slight reduction in growth under salt, and waterlogging alone was not detrimental. At high salt concentration (550 mM) differentiation occurred among genotypes for all traits. Equivalent genotypes were also planted in field trials at three sites, two with medium (583 - 847 mm) and one with low rainfall (372 - 469 mm), in southern Western Australia. Survival was low (<53%) after 9 months due to an exceptional dry season followed by 3 months waterlogging in Kirkwood (38 - 1360 mSm-1), but was high >89% after 33 months in saline fields in Sandalwindy (96 - 976 mSm-1) and Roberts (88 - 1424 mSm-1). Some families were similarly in high rank for height under saline conditions in controlled and field trials. Height had the highest narrow-sense heritability value, especially under controlled saltwaterlogging (0.85) treatment and 20% selection enabled a gain of 8-14% under controlled conditions and in the field. Leaf production under salt was not an inherited trait. Systems were developed to hasten deployment of selected material. Extended daylength (16 h) and paclobutrazol (1 mg a.i/mm stem circumference) stimulated flowering in 2 year-old plants. Clonal propagation was possible. Grafting success varied from 0-100% depending on scion/rootstock provenances. ... There was only a slight reduction in heterozygosity from species level to provenance and family levels, and two superior genotypes maintained high diversity. v Crossing was possible using one stop pollination of cut immature styles and capsule retention varied from 0-34% and germination rate from 2-96%. Genetic distance between parents was correlated with seed set and offspring fitness. Wider genetic distances increased capsule retention, seed germination and seedling survival. Under 500 mM salt-waterlogging, offspring heights were similar when parental genetic distances were similar. High heritability value for height from ANOVA-REML parental screening was confirmed using parent-offspring regression. Screened superior genotypes, which withstood very high salt concentration, provide a breeding population for further breeding and for plantations under saline regions in low-medium rainfall areas in Western Australia and other parts of the world. These trees provide an economic return in areas where no other plants may survive and an environmental service in potentially reducing waterlogging, salinity and its spread.

The remnants of the Caledonian Pine Forest represent the north western boundary of the Eurasian Pinus sylvestris (L.) distribution. Remnant populations occupy a diverse range of environments within Scotland, subject to a steep rainfall gradient, and previous investigations have found evidence of local adaptation. Additionally, studies of biochemical and molecular markers have indicated that Scotland’s native pinewoods originated from more than one glacial refugium. Whole-genome-shotgun (WGS) sequencing was employed for the discovery of mitochondrial (mt) variants that may provide further insight into the origins of P. sylvestris populations both in Scotland and mainland Europe. DNA extractions were performed on megagametophyte tissue from Scottish, Finnish, and Spanish populations. Three members of the closely related P. mugo species complex were also sequenced. Using similarity-based approach, 160kbp of putative mitochondrial sequence was recovered by comparison of de novo assembled contigs with the mtgenome of the gymnosperm Cycas taitungensis. In total, 16 novel variants were identified among samples, which may be used in future phylogeographic studies. A study of needle characters was performed for eight native populations of P. sylvestris in an outdoor provenance/progeny trial of 192 saplings. A negative correlation was detected between longitude and the number of stomatal rows present on needle surfaces. It was posited that this may be an adaptive response to lower water availability in eastern pinewoods, possibly in conjunction with increasing altitude. The west coast of Scotland is one of the wettest regions in Europe: western pinewoods may receive in excess of 3,000mm of rainfall in a year, compared with an average of 800mm eastern sites. To determine whether native pinewoods are differentially adapted to waterlogging, a glasshouse based provenance/progeny trial of 432 saplings from nine native populations was undertaken, in which 50% were subject to a long-term waterlogging treatment, and the remainder used as a control. Two studies were then conducted. In the first, responses to the treatment were assessed in terms of phenological and growth traits. Bud flush was delayed in response to waterlogging, and growth was impeded relative to the control. Although population differences were observed, treatment × population interactions were not detected. In the second study physiological traits known to be sensitive to plant stress and water balance were measured at intervals throughout the experiment. Prior to the commencement of the treatment needle δ13C was found to exhibit interpopulation differentiation, and was positively correlated with longitude. This seems likely to represent differential selection for water use efficiency between eastern and western pinewoods. Photochemical efficiency and stomatal conductance were found to be reduced by waterlogging, and needle δ13C was increased. After generalising populations into ‘high’ and ‘low’ rainfall groups (monthly averages of 214.9mm and 72.8mm, respectively), high rainfall populations were observed to maintain consistently higher photochemical efficiency under waterlogging the low rainfall populations. In addition, the low rainfall group exhibited greater variability in response to flooding (in terms of phenotypic and additive genetic variance) which may be indicative of a lack of past selection pressure.

Thesis (Ph.D.)--University of Western Australia, 2006.

No description available.

Free-swelling properties of montmorillonites in water systems were studied using X-ray diffraction techniques. Four specimen type montmorillonites (Wyoming bentonite, Otay bentonite, hectorite and nontronite) and several soil clays were selected. In Phase I of the study the differential swelling properties were related to the type of cation on the exchange complex and to variations in the mineralogical properties of the montmorillonites. / Ph. D.

A vegetação ao longo do rio Amazonas é submetida a dois períodos muito bem marcados ao longo do ano: estação de cheia e estação seca. Características morfológicas e fisiológicas das espécies de várzea foram amplamente descritas, porém, uma das principais características é o metabolismo de carboidratos que tem sido muito pouco explorada. Com o objetivo de estudar a resiliência dos carboidratos não estruturais da árvore amazônica Senna reticulata (Leguminosae), a mesma foi cultivada sob diferentes estresses abióticos, como luz baixa combinada com elevada concentração de CO2 atmosférico, bem como disponibilidade hídricas distintas (alagamento das raízes e seca). Os resultados encontrados reforçam o papel do amido nas folhas como principal órgão armazenador desta espécie e também a alta resiliência desta reserva, que foi mantida mesmo em condições de baixa irradiância, em alagamento e em condições de seca. Estes resultados também destacam a forte ligação entre as reservas de amido e a manutenção do crescimento. Além disso, esta espécie mostrou estratégias ecofisiológicas distintas em relação a diferentes estresses hídricos (alagamento x seca) e uma alta capacidade de se recuperar depois de um período de seca, padrão este que pode estar diretamente relacionado à manutenção do crescimento durante o estabelecimento de plantas jovens no primeiro período de fase terrestre / The vegetation along the Amazon River is subjected to two markedly periods: flooded and drought seasons. Morphological and physiological traits for floodplain species have been largely described; however, one of the main features is the carbohydrate metabolism, which has been poorly explored. In order to study the resilience of non-structural carbohydrates of the Amazonian tree Senna reticulate (Leguminosae), this species was grown under different abiotic stresses such as low light combined with elevated CO2 and distinct water availabilities (waterlogging and drought). Results reinforce the role of starch in leaves as a main storage organ of this species and also the high resilience of this reserve under low light, waterlogging and drought conditions. These findings also highlight the tight connection between starch reserves and growth maintenance. Additionally, this species has shown very distinct eco physiological strategies to cope with different water availabilities and a high ability to recover after drought that might be strictly related to growth maintenance during seedling establishment in the first period of terrestrial phase

A vegetação ao longo do rio Amazonas é submetida a dois períodos muito bem marcados ao longo do ano: estação de cheia e estação seca. Características morfológicas e fisiológicas das espécies de várzea foram amplamente descritas, porém, uma das principais características é o metabolismo de carboidratos que tem sido muito pouco explorada. Com o objetivo de estudar a resiliência dos carboidratos não estruturais da árvore amazônica Senna reticulata (Leguminosae), a mesma foi cultivada sob diferentes estresses abióticos, como luz baixa combinada com elevada concentração de CO2 atmosférico, bem como disponibilidade hídricas distintas (alagamento das raízes e seca). Os resultados encontrados reforçam o papel do amido nas folhas como principal órgão armazenador desta espécie e também a alta resiliência desta reserva, que foi mantida mesmo em condições de baixa irradiância, em alagamento e em condições de seca. Estes resultados também destacam a forte ligação entre as reservas de amido e a manutenção do crescimento. Além disso, esta espécie mostrou estratégias ecofisiológicas distintas em relação a diferentes estresses hídricos (alagamento x seca) e uma alta capacidade de se recuperar depois de um período de seca, padrão este que pode estar diretamente relacionado à manutenção do crescimento durante o estabelecimento de plantas jovens no primeiro período de fase terrestre / The vegetation along the Amazon River is subjected to two markedly periods: flooded and drought seasons. Morphological and physiological traits for floodplain species have been largely described; however, one of the main features is the carbohydrate metabolism, which has been poorly explored. In order to study the resilience of non-structural carbohydrates of the Amazonian tree Senna reticulate (Leguminosae), this species was grown under different abiotic stresses such as low light combined with elevated CO2 and distinct water availabilities (waterlogging and drought). Results reinforce the role of starch in leaves as a main storage organ of this species and also the high resilience of this reserve under low light, waterlogging and drought conditions. These findings also highlight the tight connection between starch reserves and growth maintenance. Additionally, this species has shown very distinct eco physiological strategies to cope with different water availabilities and a high ability to recover after drought that might be strictly related to growth maintenance during seedling establishment in the first period of terrestrial phase

Includes bibliographical references (p. B1-B24)

Thesis (Ph.D.)--University of Melbourne, School of Resource Management, Faculty of Land and Food Resources, 2006. / Typescript. Includes bibliographical references (leaves 247-274).