Koo, Siu Chung Nicolas. / Thesis submitted in: November 2007. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references (leaves 78-86). / Abstracts in English and Chinese. / Thesis committee --- p.i / Statement --- p.ii / Abstract --- p.iii / Chinese Abstract --- p.v / Acknowledgements --- p.vi / Abbreviations --- p.viii / Table of contents --- p.xi / List of figures --- p.xv / List of tables --- p.xvii / Chapter 1. --- General Introduction / Chapter 1.1 --- General introduction to salt tolerance in plant --- p.1 / Chapter 1.1.1 --- Adverse effecst of high salinity in plant cells / Chapter 1.1.1.1 --- Ion toxicity --- p.1 / Chapter 1.1.1.2 --- Disturbed osmotic homeostasis --- p.2 / Chapter 1.1.1.3 --- Oxidative stress --- p.3 / Chapter 1.1.2 --- Major salt tolerance strategy in plant / Chapter 1.1.2.1 --- Maintenance of ion homeostasis --- p.4 / Chapter 1.1.2.2 --- Maintaining osmotic homeostasis --- p.4 / Chapter 1.1.2.3 --- Detoxification of Reactive oxygen species --- p.4 / Chapter 1.2 --- Cytosolic Calcium signal in plant / Chapter 1.2.1 --- General introduction of calcium in plant --- p.6 / Chapter 1.2.2 --- Calcium transport in plant cell --- p.7 / Chapter 1.2.3 --- Cytosolic calcium signals in plant under abiotic stress --- p.9 / Chapter 1.2.4 --- Responding to cytosolic calcium signals --- p.12 / Chapter 1.3 --- Calcium mediated ion homeostasis in plant under salt stress / Chapter 1.3.1 --- General introduction on Calcium dependent ion channels in plant --- p.13 / Chapter 1.3.2 --- SOS family cascade in Arabidopsis --- p.13 / Chapter 1.4 --- The interaction between cytosolic calcium and reactive oxygen species in plants --- p.14 / Chapter 1.5 --- "Calcium signaling mediated by Inositol 1,4,5 triphosphate in plant" --- p.15 / Chapter 1.6 --- Study on HAL2 and its homolog in plant --- p.18 / Chapter 1.7 --- Previous studies on GmSAL1 in Prof. Lam's lab --- p.20 / Chapter 1.8 --- Hypothesis and significant of this project --- p.21 / Chapter 2 --- Materials and Methods / Chapter 2.1 --- Materials / Chapter 2.1.1 --- "Plants, bacterial strains and vectors" --- p.23 / Chapter 2.1.2 --- Chemicals and Regents --- p.25 / Chapter 2.1.3 --- Commercial kits --- p.26 / Chapter 2.1.4 --- Primers and Adaptors --- p.27 / Chapter 2.1.5 --- Equipments and facilities used --- p.27 / Chapter 2.1.6 --- "Buffer, solution, gel and medium" --- p.27 / Chapter 2.1.7 --- Software --- p.28 / Chapter 2.2 --- Methods / Chapter 2.2.1 --- Molecular Techniques / Chapter 2.2.1.1 --- Bacterial cultures for recombinant DNA and plant transformation --- p.29 / Chapter 2.2.1.2 --- Recombinant DNA techniques --- p.29 / Chapter 2.2.1.3 --- Preparation and transformation of Agrobacterium competent cells --- p.30 / Chapter 2.2.1.4 --- Gel electrophoresis --- p.31 / Chapter 2.2.1.5 --- DNA and RNA extractions --- p.32 / Chapter 2.2.1.6 --- Generation of single-stranded DIG-labeled PCR probes --- p.34 / Chapter 2.2.1.7 --- Testing the concentration of DIG-labeled probes --- p.36 / Chapter 2.2.1.8 --- Northern blot analysis --- p.36 / Chapter 2.2.1.9 --- PCR techniques --- p.37 / Chapter 2.2.1.10 --- Sequencing --- p.38 / Chapter 2.2.2 --- Plant cell culture and transformation / Chapter 2.2.2.1 --- Arabidopsis thaliana --- p.39 / Chapter 2.2.2.2 --- Nicotiana tabacum L. cv. Bright Yellow 2 (BY-2) cells --- p.39 / Chapter 2.2.3 --- Growth and treatment conditions for plants / Chapter 2.2.3.1 --- Growth and salt treatment condition of soybean samples for gene expression studies of GmSAL1 --- p.40 / Chapter 2.2.3.2 --- Root assay of GmSAL1l transgenic Arabidopsis thaliana --- p.41 / Chapter 2.2.4 --- "Cell viability, ROS detection and confocal microscopy" / Chapter 2.2.4.1 --- Cell viability assay --- p.42 / Chapter 2.2.4.2 --- Detection of intracellular contents of Na+ --- p.42 / Chapter 2.2.4.3 --- Detection of Reactive oxygen species (ROS) --- p.42 / Chapter 2.2.4.4 --- Confocal microscopy --- p.43 / Chapter 2.2.4.5 --- Images processing and analysis --- p.43 / Chapter 2.2.5 --- Statistical analysis --- p.44 / Chapter 3 --- Results / Chapter 3.1 --- GmSAL1 sequence analysis --- p.45 / Chapter 3.2 --- Expression of GmSAL1 was induced by NaCl stress --- p.49 / Chapter 3.3 --- Construction of GmSAL1 transgenic tobacco BY-2 cell line --- p.50 / Chapter 3.4 --- Ectopic expression of GmSAL1 alleviates NaCl stress in transgenic tobacco BY-2 cells --- p.52 / Chapter 3.5 --- GmSAL1 enhances vacuolar sodium compartmentalization in transgenic tobacco BY-2 cell under NaCl treatment --- p.55 / Chapter 3.6 --- GmSAL1 helps maintain cell turgidity in transgenic tobacco BY-2 cell under NaCl treatment --- p.58 / Chapter 3.7 --- GmSAL1 enhances ROS scavenging in transgenic tobacco BY-2 cell under NaCl treatment --- p.61 / Chapter 3.8 --- Effect of expressing GmSAL1 in Arabidopsis thaliana under salt stress --- p.64 / Chapter 4 --- Discussion --- p.66 / Chapter 4.1 --- Sequence analysis and enzyme activity of GmSAL1 --- p.68 / Chapter 4.2 --- Gene expression profile of GmSAL1 --- p.70 / Chapter 4.3 --- Functional analysis of GmSAL1 in transgenic tobacco BY-2 cells / Chapter 4.3.1 --- GmSAL1 protects transgenic BY-2 cells under salt treatment --- p.71 / Chapter 4.3.2 --- GmSAL1 regulates Na+ compartmentalization and ROS scavenging in transgenic BY-2 cells under NaCl treatment in a calcium dependent manner --- p.72 / Chapter 4.4 --- Functional tests of GmSAL1 transgenic A. thaliana --- p.75 / Chapter 5 --- Conclusion and perspective --- p.76 / References --- p.78 / "Appendix I: Substrate specificity and Km, Kcat values of GmSAL1 protein" --- p.87 / Appendix II: Restriction and modifying enzymes --- p.89 / Appendix II: Chemicals --- p.90 / Appendix III: Commercial kits --- p.94 / Appendix IV: Equipments and facilities used --- p.95 / "Appendix V: Buffer, solution, gel and medium formulation" --- p.96

Dryland salinity is a major and expanding threat to agricultural land in Australia. Animal production from forages grown on saline land is perhaps its most promising economic use. Glycophytic forage legumes have been evaluated under saline conditions mainly for agronomic characteristics and, to a lesser extent, for nutritive quality to animals. Plant growth and its nutritive quality are interrelated, but a decline in yield in response to salinity may be associated with effects on the chemical constituents of the plant since soil salinity affects plant metabolism. This research aimed to investigate changes in the components of yield and nutritive value of two legumes species. Lucerne ( Medicago sativa ) and Melilotus ( Melilotus albus ) were exposed to different levels of NaCl in the range of 0 to 110 mM NaCl. The research tested the hypothesis that the components of plant nutritive value are not as sensitive to salinity as shoot biomass production since the adaptive mechanisms of the plant lessen harmful effects of the salts. For both plant species, salinity decreased leaf and stem dry matter production, but increased leaf - to - stem ratio. In addition, salinity resulted in earlier flowering in Melilotus. Mineral composition was the most sensitive component of forage quality. Calculated sodium chloride concentrations were up to 125 g / kg DM in lucerne and 39 g / kg DM in Melilotus when irrigated with 110 mM NaCl. The concentrations of calcium and magnesium decreased in both species and approached the marginal range for animal production. Zinc concentration also decreased while potassium decreased in stems of lucerne only. The digestible organic matter ( DOMD ) in response to salinity varied between species. At the highest salt concentration, the whole shoot ( i.e., leaf and stem ) of lucerne decreased up to 4 percentage units while Melilotus increased by 6 percentage units. In lucerne, DOMD was influenced by a high concentration of soluble ash in leaf and stem and, in Melilotus, by an increase in the organic matter content of leaf and a reduction in lignin concentration in stem, which favoured higher digestibility. These results were supported by a histological study in which an increase in starch in Melilotus leaf, and a lower proportion of xylem in relation to parenchyma in stems, was measured. Crude protein concentration was not compromised and, in relation to Melilotus, coumarin concentration did not increase with salinity. In conclusion, the reduction in DM production of species with similar salt tolerance does not necessarily correspond to an equivalent reduction in nutritive value. This research represents the most detailed study into effects of salinity on glycophytic forage legumes. Results show that while some aspects of forage quality ( e.g., minerals composition and energy ) are strongly influenced by salinity, other aspects ( e.g., protein ) remain relatively unaffected. These findings have implications for development of productive grazing systems on saline agricultural land. / Thesis (Ph.D.)--School of Agriculture, Food and Wine, 2006.

Bibliography: leaves 119-218. / xiv, 218 leaves : ill. (some col.), maps (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Salt Manager represents the software system developed by this thesis to implement an interactive land classification methodology. An Expert System (ES), a Geographic Information System (GIS), remotely sensed information and a relational database management system (RDBMS) have been utilised to construct the methodology. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geography, 1995

Dryland salinity is a major and expanding threat to agricultural land in Australia. Animal production from forages grown on saline land is perhaps its most promising economic use. Glycophytic forage legumes have been evaluated under saline conditions mainly for agronomic characteristics and, to a lesser extent, for nutritive quality to animals. Plant growth and its nutritive quality are interrelated, but a decline in yield in response to salinity may be associated with effects on the chemical constituents of the plant since soil salinity affects plant metabolism. This research aimed to investigate changes in the components of yield and nutritive value of two legumes species. Lucerne ( Medicago sativa ) and Melilotus ( Melilotus albus ) were exposed to different levels of NaCl in the range of 0 to 110 mM NaCl. The research tested the hypothesis that the components of plant nutritive value are not as sensitive to salinity as shoot biomass production since the adaptive mechanisms of the plant lessen harmful effects of the salts. For both plant species, salinity decreased leaf and stem dry matter production, but increased leaf - to - stem ratio. In addition, salinity resulted in earlier flowering in Melilotus. Mineral composition was the most sensitive component of forage quality. Calculated sodium chloride concentrations were up to 125 g / kg DM in lucerne and 39 g / kg DM in Melilotus when irrigated with 110 mM NaCl. The concentrations of calcium and magnesium decreased in both species and approached the marginal range for animal production. Zinc concentration also decreased while potassium decreased in stems of lucerne only. The digestible organic matter ( DOMD ) in response to salinity varied between species. At the highest salt concentration, the whole shoot ( i.e., leaf and stem ) of lucerne decreased up to 4 percentage units while Melilotus increased by 6 percentage units. In lucerne, DOMD was influenced by a high concentration of soluble ash in leaf and stem and, in Melilotus, by an increase in the organic matter content of leaf and a reduction in lignin concentration in stem, which favoured higher digestibility. These results were supported by a histological study in which an increase in starch in Melilotus leaf, and a lower proportion of xylem in relation to parenchyma in stems, was measured. Crude protein concentration was not compromised and, in relation to Melilotus, coumarin concentration did not increase with salinity. In conclusion, the reduction in DM production of species with similar salt tolerance does not necessarily correspond to an equivalent reduction in nutritive value. This research represents the most detailed study into effects of salinity on glycophytic forage legumes. Results show that while some aspects of forage quality ( e.g., minerals composition and energy ) are strongly influenced by salinity, other aspects ( e.g., protein ) remain relatively unaffected. These findings have implications for development of productive grazing systems on saline agricultural land. / Thesis (Ph.D.)--School of Agriculture, Food and Wine, 2006.

Lucerne is a deep-rooted perennial pasture that is promoted to land managers in southern Australia to mitigate the effects of dryland salinity, a problem of national significance caused by the replacement of native trees and shrubs with annual crops and pastures. In recent years, the acceptance of climate change has provided further rationale for increasing the use of perennial legumes in our farming systems. Perennial legumes have a role in offsetting C02 emissions by sequestering C and N in soil, and provide new, resilient options for future farming in a warmer and more variable climate. This research has focused on evaluating the diverse range of germplasm found in lucerne (Medicago sativa spp.) for a range of attributes in order to determine its compatibility with existing and future farming systems in southern Australia. Regional field evaluation at 8 sites in southern Australia showed that lucerne is a broadly adapted and robust plant. After 3 years, plant density ranged from 2-55 plants / m2 with differences in persistence attributed to tolerance to a combination of stresses including soil acidity, saline and sodic subsoils, drought conditions and persistent heavy grazing. Highly winter-active lucerne (class 9-10) was confirmed to be the most suitable group for short phase rotations in southern Australia, providing grazing is well managed. This germplasm was less persistent than other winter activity groups, but produces more total herbage yield in environments with winter dominant rainfall patterns. Highly winter-active lucerne has poor persistence under continuous grazing, but this may aid in its removal when used in rotation with crops. Winteractive germplasm (class 6-8) was more grazing tolerant and persistent, making it the most suitable group for longer phase rotations (>4 years), or where more flexible grazing management practices are required (i.e. 35 days grazing followed by 35 days recovery). Individual grazing tolerant plants from this group were selected and randomly inter-mated to form new breeder’s lines in the development of a grazing tolerant cultivar. For the first time, the high water-use of a farming system involving wheat overcropped into lucerne is presented. Lucerne over-cropped with wheat used an additional 43-88 mm of water in comparison to continuous wheat at Roseworthy and Katanning respectively. Over-cropping reduced wheat yield by 13-63%, but it can be more efficient in terms of land area to grow lucerne and wheat as a mixture than on separate parcels of land. Very winter-dormant lucerne (class 1-2) appears to be less competitive with winter cereal crops during wheat establishment. It may also be possible to reduce lucerne’s competition with wheat at the critical stage of anthesis, with low spring yielding lucerne varieties identified in this research (SA37908). This group of plants provides excellent potential for the development of high water-use farming systems because they are grazing tolerant and persistent, and have summer forage production and sub-soil water extraction rates that are equivalent to winter active lucerne. The research has been used to identify the perfect ideotype for lucerne in phase farming and over-cropping systems, which can be used to set targets in future breeding programs. The research also highlights current opportunities for the integration of lucerne into southern Australian farming systems to help curb the spread of dryland salinity and reduce the impact of climate change. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1344608 / Thesis (Ph.D.) - University of Adelaide, School of Agriculture, Food and Wine, 2008