Oxygen isotope discrimination during C4 photosynthesis. Plants with the C4 photosynthetic pathway, like sugarcane and pasture grasses, are vital to Australian agriculture and natural ecosystems. This project will use novel laser spectroscopy to measure oxygen isotope discrimination during photosynthesis and quantify the influence of C4 plants on isotopic signatures of atmospheric CO2.
Using Arabidopsis mutants to discover the role of guard cell chloroplasts in the stomatal response to light. This project will use novel molecular approaches to study how guard cells on the surface of leaves regulate plant water loss and CO2 uptake. This will provide new molecular tools for improving plant water use in agricultural species and aid process based modelling of CO2 and water exchange needed for predicting climate change.
Unsaturation of vapour pressure inside leaves: fundamental, but unknown. This project aims to determine when and to what extent the air inside leaves becomes unsaturated with water vapour. All current interpretation and modelling of leaf gas exchange assumes saturation under all circumstances. Compelling evidence has been obtained that suggests this is not true under moderate air vapour pressure deficits. A novel technique will be employed to assess the water vapour concentration of the air insi ....Unsaturation of vapour pressure inside leaves: fundamental, but unknown. This project aims to determine when and to what extent the air inside leaves becomes unsaturated with water vapour. All current interpretation and modelling of leaf gas exchange assumes saturation under all circumstances. Compelling evidence has been obtained that suggests this is not true under moderate air vapour pressure deficits. A novel technique will be employed to assess the water vapour concentration of the air inside leaves based on stable isotope analysis of carbon dioxide and water vapour exchanged between leaves and air. The project is expected to provide fundamental knowledge about how stomata regulate photosynthesis and water use, with significant implications for modelling vegetation function and for improving the performance of crop plants.Read moreRead less
Disentangling climate and evolutionary controls over the temperature dependence of leaf respiration. The project will use field and laboratory studies to establish if there are systematic differences in the temperature responses of leaf respiration in plants adapted to hot and cold environments. The results will enable climate modellers to better predict impacts of climate change on carbon exchange between vegetation and the atmosphere.
A step change in modeling leaf respiration-photosynthesis relationships . This project aims to use innovative, high-throughput technologies to develop a novel framework that links daytime photosynthesis and starch/amino acid mobilisation to variations in night-time leaf respiration. Variations in leaf respiration can have large impacts on ecosystem functioning and the Earth’s climate. Although advances have been made in respiration modelling, current models are unable to predict dynamic, day-to- ....A step change in modeling leaf respiration-photosynthesis relationships . This project aims to use innovative, high-throughput technologies to develop a novel framework that links daytime photosynthesis and starch/amino acid mobilisation to variations in night-time leaf respiration. Variations in leaf respiration can have large impacts on ecosystem functioning and the Earth’s climate. Although advances have been made in respiration modelling, current models are unable to predict dynamic, day-to-day variations in respiratory rates. Expected outcomes include equations that predict daily variations in night-time leaf respiration for environments across Australia and overseas. Benefits to planners include the ability to more accurately model vegetation-atmosphere carbon exchange and future changes in climate. Read moreRead less
The causes and effects of mortality in tropical Australian trees. Drought can cause the widespread death of tropical trees resulting in large emissions of carbon dioxide to the atmosphere, but predictions of tree death during drought remain rudimentary. This project will combine new data and modelling on how Australian tropical trees respond to drought to improve estimates of tree mortality risk and its impacts.
Physiological and molecular controls of plant transpiration efficiency: investigating the role of the ERECTA gene. Water is the single most limiting factor in agriculture and the world's supply of fresh water is diminishing, the greatest fraction of total water use being by agriculture. Progress in water-use efficiency will have social value, and this program should help us to achieve it. Our progress in this area is already one of the most successful of 'bottom-up' approaches - in the sense of ....Physiological and molecular controls of plant transpiration efficiency: investigating the role of the ERECTA gene. Water is the single most limiting factor in agriculture and the world's supply of fresh water is diminishing, the greatest fraction of total water use being by agriculture. Progress in water-use efficiency will have social value, and this program should help us to achieve it. Our progress in this area is already one of the most successful of 'bottom-up' approaches - in the sense of transferring knowledge from biochemistry and biophysics to breeding and agronomy, as CSIRO now has a successful wheat breeding program based on this earlier work of ours. Now that we have discovered a gene that controls water-use efficiency at the leaf level, we wish to see how the gene works, and how it affects mineral nutrition of leaves.Read moreRead less
Understanding leaf water isotope composition. This project aims to quantify variation in leaf water isotopes and develop mechanistic models for paleoclimatologists and plant scientists to constrain global carbon cycles. Leaf water stable isotopes influence the isotope compositions of atmospheric oxygen, carbon dioxide and water vapour, and impart an evaporative signal on the isotope composition of plant organic material. These isotope signals have been used to constrain global carbon and water c ....Understanding leaf water isotope composition. This project aims to quantify variation in leaf water isotopes and develop mechanistic models for paleoclimatologists and plant scientists to constrain global carbon cycles. Leaf water stable isotopes influence the isotope compositions of atmospheric oxygen, carbon dioxide and water vapour, and impart an evaporative signal on the isotope composition of plant organic material. These isotope signals have been used to constrain global carbon and water cycles and reconstruct past climates. This project aims to quantify variation in leaf water isotopes and develop mechanistic models for use by paleoclimatologists, plant scientists and to constrain global carbon cycles and develop accurate models of leaf water isotopes to reduce uncertainty in climate models.Read moreRead less
Proteome Analysis of Plant Response Pathways to Microbial Signals in the Model Legume, Medicago truncatula. This project will investigate plant responses to soil microbes in the model legume, Medicago truncatula, to provide fundamental information needed to design crops with improved abilities to interact beneficially with soil microbes. Plant development and performance are significantly influenced by soil microbes, but it is largely unknown how the information contained in microbial signalling ....Proteome Analysis of Plant Response Pathways to Microbial Signals in the Model Legume, Medicago truncatula. This project will investigate plant responses to soil microbes in the model legume, Medicago truncatula, to provide fundamental information needed to design crops with improved abilities to interact beneficially with soil microbes. Plant development and performance are significantly influenced by soil microbes, but it is largely unknown how the information contained in microbial signalling molecules is relayed to plants. Proteome analysis and immunocytochemistry will be combined to identify and localise differentially expressed proteins in roots treated with specific microbial signal molecules. Annotated Proteome databases will be generated to strengthen and complement an international project on M. truncatula genome analysis.Read moreRead less
How do nano-molecular carboxysome protein structures function in alpha and beta-cyanobacteria and can we use them for novel reaction compartmentalisation? In blue-green algae, protein nano-structures, known as carboxysomes, act as tiny compartments where carbon dioxide (CO2) can be fixed into simple sugars at high efficiency. This important photosynthetic process forms the basis of global primary productivity on this planet, but most land-based CO2 fixation lacks the efficiency seen in blue-gree ....How do nano-molecular carboxysome protein structures function in alpha and beta-cyanobacteria and can we use them for novel reaction compartmentalisation? In blue-green algae, protein nano-structures, known as carboxysomes, act as tiny compartments where carbon dioxide (CO2) can be fixed into simple sugars at high efficiency. This important photosynthetic process forms the basis of global primary productivity on this planet, but most land-based CO2 fixation lacks the efficiency seen in blue-greens. This research aims to determine how the proteins that make up carboxysomes are 3-dimensionally arranged and how these structures function to enhance rates of CO2 fixation. A more thorough understanding of the carboxysome is likely to have potential applications in industrial nano-technology and improve our understanding of oceanic primary productivity.Read moreRead less