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
Will stomatal responses to humidity and carbon dioxide constrain tropical forest productivity as atmospheric carbon dioxide rises? This project will investigate two physiological processes that will partly determine growth responses of tropical forest trees to rising atmospheric carbon dioxide. The project will produce equations summarising physiological responses that can be incorporated into process-based models of tropical forest productivity.
Reading the isotopic archive: carbon and oxygen stable isotope ratios as recorders of plant physiological processes. This project will investigate how plant physiological processes are reflected in stable isotope ratios of carbon and oxygen in plant tissues. Results will contribute towards a mechanistic understanding of the processes that cause isotopic modifications, thereby enabling an improved interpretation of naturally occurring stable isotope signals.
On the physiology of plant transpiration. This project aims to better understand plant transpiration. It is significant from both a basic and a practical perspective. It intends to solve a conundrum of the biophysics of the evaporative sites within leaves. That is, in dry air, the relative humidity of intercellular air spaces suggests much lower liquid water potentials than those typically measured. At a practical level, the failure to sustain transpiration in dry conditions leads to desiccation ....On the physiology of plant transpiration. This project aims to better understand plant transpiration. It is significant from both a basic and a practical perspective. It intends to solve a conundrum of the biophysics of the evaporative sites within leaves. That is, in dry air, the relative humidity of intercellular air spaces suggests much lower liquid water potentials than those typically measured. At a practical level, the failure to sustain transpiration in dry conditions leads to desiccation and tissue death, and plants differ in this vulnerability. The aim is to apply a novel nanoparticle technique to measure the water potential distribution within the leaf, identify hydraulic resilience attributes, and develop a modern theory of optimal transpiration under varying conditions.Read moreRead less