Water transport and water stress in grapevines: new insights using novel imaging techniques.
Listen to Dr Brendan Choat’s talk which was given at the 2nd Robyn van Heeswijck Lecture on the 28th March, 2011.
Plants are capable of transporting water to heights in excess of 100 m, and can extract water from drying and saline soils. To achieve this, they have evolved a transport system that relies on water sustaining a tensile force, such that the xylem sap is at negative absolute pressures. However, this transport mechanism comes with its own set of problems; most notably that water under tension is prone to the formation of emboli, gas bubbles that block xylem conduits and reduced the ability of the plant to move water to the canopy. W, xylemater stress is the principal cause of embolism, which can lead to declines in productivity and ultimately, plant death.
Grapevines are commonly exposed to water stress in the field and are therefore vulnerable to embolism during the growing season. Given predictions of more prolonged and severe droughts associated with climate change, a proper understanding of how water stress induced embolism may limit productivity in grapevines is of great importance to the Australian grape and wine industry. My research addresses two unresolved questions related to plant water transport. First, how resistance to water stress induced embolism differs between plant species and cultivars and second, how plants are able to repair embolised xylem conduits and thus restore lost transport capacity. Recent advances in imaging technology such as micro computed tomography and magnetic resonance imaging provide an opportunity to observe plant water transport at unparalleled resolution and in real time. These results show that grapevines are capable of repairing embolism on diurnal timescales and give insights into the physiological mechanism by which repair is achieved.
Short Speaker Biography
Brendan Choat obtained his BSc (Hons) in 1997 (JCU) and his PhD in 2003 (JCU). From 2003-2005 he worked as a Post Doctoral Fellow at Harvard University in the Department of Organismic and Evolutionary Biology. He held a second Post Doctoral Fellowship in the Department of Viticulture and Enology at the University of California, Davis from 2005-2008. In 2008 he returned to Australia to take up a Research Fellowship at ANU before moving to a Senior Research Lectureship at the Hawkesbury Institute for the Environment (UWS). He is an editor for the PrometheusWiki Project and on the editorial review board of Tree Physiology. In 2010 he was awarded a Humboldt Fellowship for Experienced Researchers.