Plant hydraulics - i.e. the mechanisms by which plants transport water -is a cross-disciplinary science of particular importance in Australia due to the scarcity of water and seasonal climate drivers such as El Nino and the Indian Ocean Dipole.
Plants operate with high levels of negative pressure (tension) within their tissue and water transportation pathways. This is a necessary strategy to allow the plant to draw water from clay-like soils and to avoid excessive evaporation at the leaves, but it exposes plants to the risk of embolism - the formation of air bubbles that disconnect flow pathways. Drought-tolerant plants have evolved remarkable abilities to survive dry periods and can sustain extreme negative pressures of tens or hundreds of atmospheres.
A number of basic questions about the mechanisms of drought-tolerance remain controversial. For example: are drought-tolerant plants better at avoiding embolisms, or have they evolved the ability to refill embolised vessels? Is drought-tolerance entirely about xylem or are the surrounding tissues also important? Can species draw water from their leaves when the soil is dry but the air humid?
X-ray micro-tomography is a non-destructive 3D imaging technique that provides a means to observe plants resisting water stress in real time. This project will collaborate with researchers in the Research School of biology to make 3D images of plants using unique 3D X-ray micro-CT instruments and analysis techniques developed in RSPhys.