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.
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.
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
Resilience of eucalypts to future droughts. This project aims to examine how resilient Eucalyptus species are to future droughts by combining data synthesis, manipulative experiments and modelling. Climate change is expected to increase the frequency, magnitude and duration of future droughts, with major environmental and socio-economic consequences for Australia. Current predictive capacity is extremely limited: experiments are limited in scale and cannot capture important global change interac ....Resilience of eucalypts to future droughts. This project aims to examine how resilient Eucalyptus species are to future droughts by combining data synthesis, manipulative experiments and modelling. Climate change is expected to increase the frequency, magnitude and duration of future droughts, with major environmental and socio-economic consequences for Australia. Current predictive capacity is extremely limited: experiments are limited in scale and cannot capture important global change interactions, whilst models do not represent the functional characteristics and adaptions of eucalypts. This project will develop a strong evidence- and process-based understanding to quantify the functional behaviour of drought-adapted Eucalyptus species and leverage this insight to make future model projections.Read moreRead less
What determines plant sensitivity to heat?: Individual to lifetime impacts. Temperature is a major determinant of the distribution of species and yet the capacity to predict the thermal sensitivity of plants is extremely limited. How vulnerability varies as a plant grows from seed to adult and produces more seed is a key question. Whether chronic warming exacerbates or ameliorates effects of extreme events, e.g. triggering the plant to enlist defensive strategies, is also an open question. This ....What determines plant sensitivity to heat?: Individual to lifetime impacts. Temperature is a major determinant of the distribution of species and yet the capacity to predict the thermal sensitivity of plants is extremely limited. How vulnerability varies as a plant grows from seed to adult and produces more seed is a key question. Whether chronic warming exacerbates or ameliorates effects of extreme events, e.g. triggering the plant to enlist defensive strategies, is also an open question. This project will advance fundamental understanding of how thermal tolerance varies across species and over the plant life cycle and how it scales demographically to lifetime vulnerability. The work will yield a significant advance in our capacity to predict impacts of extreme heat events on plant performance and distribution.
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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
Revealing the impacts of super-charged photosynthesis on leaf respiration. This project aims to use state-of-the-art technologies to develop a novel framework that links a super-charged version of photosynthesis (known as C4 photosynthesis) to changes in nocturnal leaf respiration. A quarter of global land photosynthesis occurs in C4 plants that include several important cereal crops. Although advances have been made in modelling C4 photosynthesis, these advances are unable to model variations i ....Revealing the impacts of super-charged photosynthesis on leaf respiration. This project aims to use state-of-the-art technologies to develop a novel framework that links a super-charged version of photosynthesis (known as C4 photosynthesis) to changes in nocturnal leaf respiration. A quarter of global land photosynthesis occurs in C4 plants that include several important cereal crops. Although advances have been made in modelling C4 photosynthesis, these advances are unable to model variations in nocturnal respiration. Expected outcomes include equations that predict respiration in C4 plants growing in current/future climates. Benefits to include knowledge needed to engineer faster-growing crops and providing climate modelers the ability to more accurately predict carbon exchange in C4-dominated ecosystems. Read moreRead less