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Full-Text Articles in Life Sciences

The Effect Of Irrigation On Soil Water Availability And The Plant Water Relations Of Three Species Growing On Revegetated Bauxite Residue Disposal Areas, Sharyn Burgess Jan 2007

The Effect Of Irrigation On Soil Water Availability And The Plant Water Relations Of Three Species Growing On Revegetated Bauxite Residue Disposal Areas, Sharyn Burgess

Theses : Honours

The waste product resulting from the alumina refining process consists of residue sand and mud which is laid on bauxite residue disposal areas (RDAs). Once the RDAs have been effectively solar dried they are revegetated to minimise deep drainage and potential groundwater contamination. In this study, two RDAs located at Alcoa's Pinjarra refinery were seasonally monitored to determine the effects of irrigation on soil water availability and plant water use. Three experimental Blocks were established by Alcoa, each with an irrigated and unirrigated site. Since then, irrigation has been applied to the three treated sites to maintain the root zone …


Water Stress Vulnerability Of Four Banksia Species In Contrasting Ecohydrological Habitats On The Gnangara Mound, Western Australia, Caroline Canham Jan 2006

Water Stress Vulnerability Of Four Banksia Species In Contrasting Ecohydrological Habitats On The Gnangara Mound, Western Australia, Caroline Canham

Theses : Honours

The distribution of obligate and facultative phreatophytic vegetation reflects the gradient of ecohydrological habitats in a landscape. Preliminary investigations of Banksia vulnerability to xylem embolism have reported that obligate phreatophytes are more susceptible to water stress than facultative phreatophytes (Froend & Drake 2006). A quantitative measure of plant susceptibility to water stress is vital when establishing environmental water requirements. This study investigated interspecific differences in vulnerability to water stress for two facultative phreatophytes (B. attenuata and B. menziesii) and two obligate pln·eatophytes (B. ilicifolia and B. littoralis) at the same position along an ecohydrological gradient on the Gnangara Groundwater Mound, …


The Effects Of Light Reduction Treatments On Mobile Epifaunain An Amphibolis Griffithii (Black) Den Hartog Seagrass Ecosystem, Helen Barwick Jan 2006

The Effects Of Light Reduction Treatments On Mobile Epifaunain An Amphibolis Griffithii (Black) Den Hartog Seagrass Ecosystem, Helen Barwick

Theses : Honours

One of the main anthropogenic disturbances to seagrass meadows in Australia is reduction in light availability, through nutrient enrichment or suspended sediments. Dredging can create suspended sediment plumes from the expulsion of particulates into the water column and in tum reduces light penetration to seagrass ecosystems. Preliminary investigations have demonstrated that light reduction for different intensities and durations results in reduced seagrass and epiphytic algae biomass. The main aim of this study was to determine the effects of different intensities and durations of light reduction on epifaunal assemblages in Amphibolis griffithii seagrass meadows in Jurien Bay, Western Australia. This was …


Patterns Of Water Uptake And Rhizosphere Salinity In Casuarina Obesa Miq. During A Drying Period At Lake Toolibin, Western Australia, Patrick J. Mitchell Jan 2003

Patterns Of Water Uptake And Rhizosphere Salinity In Casuarina Obesa Miq. During A Drying Period At Lake Toolibin, Western Australia, Patrick J. Mitchell

Theses : Honours

Lake Toolibin is one of a few remaining freshwater lakes in the central wheatbelt of Western Australia. Since monitoring began at Lake Toolibin in the early 1970's groundwater levels have risen to within 1-2 m of the lakebed with an accompanying migration of salt. The site-specific nature of water uptake in Casuarina obesa Miq. (the dominant lakebed tree species) and rhizosphere salinity were explored spatially through analyses of soil properties (groundwater depth and salinity, particle size and components of soil water potential ψ1). Plant water sources (using δ2H signatures) and water availability (based on ψleaf …


Salinity Tolerance Of Selected Ectomycorrhizal Fungi (Pisolithus Tinctorius Pers.) And Ectomycorrhizal Eucalypts, Ben Bradshaw Jan 2000

Salinity Tolerance Of Selected Ectomycorrhizal Fungi (Pisolithus Tinctorius Pers.) And Ectomycorrhizal Eucalypts, Ben Bradshaw

Theses : Honours

Increasing soil salinity has become a major problem worldwide. It has led to a reduction in the amount of arable land, has put at risk the supply of freshwater and threatens the existence of many natural habitats. The major increase in salinity has been attributed to human activities such as clearing of natural vegetation and large-scale irrigation programmes. The alleviation of this problem has focussed on changed management strategies. the most significant of which is the re-establishment of deep rooted plants in sail affected areas. This, however, is difficult because of the variation in salt tolerance of such plants and …


A Solid Phase Extraction System For The Isolation Of The Germination Cue In Smoky Water When Subjected To The Light Sensitive Lettuce Lactuca Sativa V. Grand Rapids, Troy David Adriansz Jan 1998

A Solid Phase Extraction System For The Isolation Of The Germination Cue In Smoky Water When Subjected To The Light Sensitive Lettuce Lactuca Sativa V. Grand Rapids, Troy David Adriansz

Theses : Honours

The search for the chemical or set of chemicals that act as a germination stimulant in Lactuca sativa v. Grand rapids (a variety of lettuce seed) was the underlying basis of this project. Through the development of a solid phase extraction (SPE) system different fractions of smoky water were tested for their effects on germination enhancement. The project targeted streamlining the amount of solvents as well as time used in past research on smoky water. Previously, several steps involving high perfo1mance liquid chromatography (HPLC), thin layer chromatography (TLC) and Gas Chromatography (GC) were employed. This project used SPE cartridges to …


Comparative Salt And Waterlogging Tolerance Of An Introduced Grass (Agropyron Elongatum [Host] P. Beauv.) And Two Herbaceous Australian Species (Podolepis Gracilis [Lehm.] And Danthonia Caespitosa Gaud.), Bryan William Duff Jan 1997

Comparative Salt And Waterlogging Tolerance Of An Introduced Grass (Agropyron Elongatum [Host] P. Beauv.) And Two Herbaceous Australian Species (Podolepis Gracilis [Lehm.] And Danthonia Caespitosa Gaud.), Bryan William Duff

Theses : Honours

Increasing land degradation is recognised as an immediate worldwide threat. Human induced soil salinity is probably the major cause of land abandonment, through its adverse effects on plant growth. Salinity is a major focus of environmental researchers because it is recognised that counter-strategies can potentially reclaim both artificially degraded lands and intrinsically saline areas. Currently, strategies to combat salinity require that land use is changed, since restoration to a past use is usually economically impractical or impossible. Biological strategies show most promise. Revegetation of degraded soils with hardy plant species has met with considerable success, and shows promise for the …


Effect Of Carbohydrate Source, Auxin And Endogenous Ethylene Upon Root Induction Of Eucalyptus Marginata Donn Ex Sm. In Vitro, Meredith Magaret Fairbanks Jan 1996

Effect Of Carbohydrate Source, Auxin And Endogenous Ethylene Upon Root Induction Of Eucalyptus Marginata Donn Ex Sm. In Vitro, Meredith Magaret Fairbanks

Theses : Honours

The utilisation of eucalypts around the world is increasing, mainly through the development of plantations. Clonal propagation has become important in some countries for production of such plantation trees. Micropropagation has been utilised to produce clones of trees selected for specific characteristics such as disease resistance, salt tolerance and fast growth rates. However, a suitable micropropagation protocol for all eucalypts has not been produced. One component of the micropropagation protocol, in which there is considerable difficulty, is the induction of adventitious roots on micropropagated shoots. Of particular interest, is the development of these procedures for Eucalyptus marginata (Jarrah) that have …


Phenolic And Lignin Concentration As An Indicator Of Resistance To Phytophthora Cinnamomi In Banksia Species, Sandra Jane Nicoski Jan 1996

Phenolic And Lignin Concentration As An Indicator Of Resistance To Phytophthora Cinnamomi In Banksia Species, Sandra Jane Nicoski

Theses : Honours

Phytophthora cinnamomi Rands, a soilborne fungus, is regarded as one of the most devastating pathogens yet recorded in natural ecosystems. The disease, caused by P. cinnamomi, poses an enormous threat to the flora of the southwest. The Proteaceae, in particular, contribute considerably to species richness and provide the fundamental floristic structure of many south-western plant communities. The genus Banksia, a member of the Proteaceae, is very susceptible to disease caused by P. cinnamomi. Three species, namely B. attenuata, B. grandis and B. menziesii. Were established in an aeroponics system under glasshouse conditions. Trials were conducted to optimise growing conditions in …


Development And Optimisation Of A Micellar Electrokinetic Capillary Chromatography Method For The Separation And Identification Of Phenolics From Eucalypt Species, Andrew J. Tromans Jan 1996

Development And Optimisation Of A Micellar Electrokinetic Capillary Chromatography Method For The Separation And Identification Of Phenolics From Eucalypt Species, Andrew J. Tromans

Theses : Honours

Several buffers were examined for their ability to separate a complex mixture of phenolic compounds using micellar electrokinetic capillary chromatography (MEKC). The phenolic mixture included simple phenols, phenolic acids and coumarins. Of the different buffers examined, 6 mM borate, 10 mM phosphate, 100 mM SDS, pH 8.3 gave the best separation. The ability of organic modifiers, complexation agents such as α cyclodextrin, β cyclodextrin and mixed SDS I Brij 35 micelles to improve the separation and peak retention time reproducibility of the buffer system was investigated. Baseline separation of the 18 phenolics was achieved by the 6 mM borate, 10 …


Proline Concentration As An Indicator Of The Level Of Salt Tolerance, Philomena Y. Rosalie Jan 1995

Proline Concentration As An Indicator Of The Level Of Salt Tolerance, Philomena Y. Rosalie

Theses : Honours

Each year approximately 20 million hectares of land become affected by increasing salinity. Salt tolerant plants are being used to rehabilitate salt affected areas. Plants use a variety of mechanisms to adapt to salt in their environments. Glycophytes tolerate low to moderate levels of salt while halophytes can tolerate very high salt levels. Many basic physiological attributes have been suggested as important components of a salt tolerant phenotype. These include, influx and/or efflux of ions across plasma membrane and the tonoplast, modification of membrane composition and synthesis of compatible solutes such as soluble carbohydrates, glycine betaines and proline. The project …