xvi, 227 leaves : ill. ; 26 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Plant Physiology, 1971

xxi, 299 leaves : ill. ; 25 cm / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.1976) from the Dept. of Plant Physiology, University of Adelaide

Bibliography: leaves 98-123. This thesis investigates the symptoms of leaf senescence in response to plant shoot water stress and demonstrates the effect of a non-hydraulic root signal in the senescence response of mature leaves of sunflower. The alleviation of the leaf soluble protein loss rate by excision of the root system in drying soil indicates that this signal originates in roots in dry soil and acts to promote protein loss.

PhD (Geography) / Department of Geography and Geo-Information Sciences / Conservation agriculture (CA) which is an agricultural system with the capabilities of conserving soil and water through its zero to minimal tillage, mulching and crop rotation principles has become popular the world over. This study evaluated CA as an adaptation tool to drought in Chivi district, Zimbabwe. It developed a model to enhance adaptation to drought in Chivi and other areas of similar environment. The VLIR-UOUS (2019) Theory of Change (ToC) principles structured interview checklist was used to review the Logical Framework of CA to establish the project design. Questionnaires, key informant interviews and Focus Group Discussions were used to characterise the nature of CA in Chivi and to assess the socio-economic impact of the project. Official records were used to compare food crop production yields per hectare under conventional and conservation agriculture. Atlas.ti 8‘s capabilities such as Co oc for frequency of occurrence, Co-code Doc Table for numeric analysis, Networks and report tools for visual and text analysis were employed in data analysis. Statistical Package for Social Science (SPSS version 22) was used for its uni-variate and bivariate analysis capabilities. The findings highlighted weaknesses in the Chivi CA principles and project design. It noted a low adoption of the project with some farmers withdrawing from the project against a downward trend in food production, despite CA having higher yields per hectare. The study also noted low socio-economic impact of CA as a project and its potential outside the project framework. The study concludes that CA has can alleviate the drought effects if the project’s framework is adjusted to suit local context / NRF

MENVSC / Department of Geography and Geo-Information Sciences / South Africa was badly affected by the recent 2015/16 severe drought. Water levels in dams declined drastically resulting in decimation of livestock herds and widespread crop failure. Mopani District Municipality is comprised of many agricultural activities that contribute to the economy and social development of the country. The study evaluated the nature of the drought hazard - its impacts, vulnerability and adaptation strategies employed by rural communities of Mopani District. The study used a mixed method approach with both quantitative and qualitative datasets. The district was divided into two distinct climatic areas, the eastern lowveld which includes the Greater-Giyani, Ba-Phalaborwa and Maruleng Local Municipalities and the western highveld which includes Greater- Tzaneen and Greater- Letaba Local Municipalities. Questionnaires were administered among community members whilst key informant interviews were conducted among relevant government and municipal officials. Anomalies in long term climate data were analysed to determine the frequency and intensity of drought in the district. Drought characterisation was done using a Standardised Precipitation and Evapotranspiration Index whilst vegetation anomaly maps, maize yields and dam level data were used to analyse the impacts of drought across the district. Levels of vulnerability to drought were determined using the Household Vulnerability Index. Spatially distinct patterns of drought conditions across the district were remarkable with wet conditions on the western highveld along the escarpment and harsh dry conditions towards the eastern lowveld. It was found that nearly half the time there is some form of drought or another in the district which may be linked to the remote El Nino phenomenon. Community vulnerabilities have a direct impact on human welfare and different strategies are employed to adapt to drought hazards both at community and district levels. The study showed a link between drought hazard extent and vulnerability. Community members are adapting using conservation agriculture, selling fire-wood, accessing boreholes and rearing chickens, amongst other means to survive in these harsh climatic conditions. Local government intervention strategies include supply of seeds and fertilisers, selling fodder at a cheaper price and supplying water using trucks. The findings of this study contribute to disaster risk reduction efforts in Mopani District Municipality / NRF

Indiana University-Purdue University Indianapolis (IUPUI) / Drought and cold conditions are among the major factors affecting plant growth and crop production globally. Dehydrins are group II late embryogenesis abundant (LEA) proteins characterized by a conserved K-region (EKKGIMDKIKEKLPG consensus sequence) that accumulate in many plants during drought, low temperature, and high salinity to confer stress tolerance. While it has been demonstrated that overexpression of dehydrins improves cold tolerance in various crop plants, the mechanism leading to cold tolerance is still unclear. Previous studies reported phosphorylation of AtERD14 dehydrin by casein kinase II (CKII) led to an increase in calcium binding activity. Mass spectroscopy analysis determined that the phosphorylation was localized to a poly-serine (S) region. To further characterize the S-region, GST fused ERD14 mutants were created via site-directed mutagenesis and deletion of either the amino or carboxyl ends of ERD14 via the QuickChange® Multi Site-Directed Mutagenesis Kit. Phosphorylation of purified mutant proteins by CKII was analyzed via gel shift and direct phosphorylation assays. The effect of phosphorylation on calcium binding activity was also analyzed. Results showed the serine (S) residue at position 83 was crucial to phosphorylation-dependent molecular mass shift and Ca2+-binding activities followed by the serine residue at position 85 in importance. Mutation of serines at positions 83, 84, and 85 completely eliminated the phosphorylation-dependent gel shift and calcium binding. Examination of truncation mutants determined the N-terminal was an important region for protein structure modification and phosphorylation ability leading to Ca2+ activation. Calcium binding activity of the truncated mutants indicated the calcium binding site was localized in the region between the S-region and the K-region near the C-terminal end. To characterize the acidic dehydrins contribution to cold tolerance in vivo, three single (erd10, erd14, cor47) knockouts (KOs) were characterized. Single KOs produced no cold sensitive phenotype indicating the need for multiple dehydrin KOs in Arabidopsis in order to potentially produce a cold sensitive phenotype.