Tag Archives: transport

Robyn van Heeswijck Lecture – Podcast

Dr Brendan Choat

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.

Robyn van Heeswijck Lecture

The 2nd Robyn van Heeswijck Lecture will be held on Monday 28th March 2011, 4pm Plant Research Centre, Waite Campus, University of Adelaide


Dr Brendan Choat, University of Western Sydney, Hawkesbury Institute for the Environment

Water transport and water stress in grapevines: new insights using novel imaging techniques.

For more information please refer to the website.

The audience is invited to stay and talk with the speaker and colleagues over refreshments.

Distinguished visitor Seminar – Podcast

Prof Ulrich Zimmermann

How do plants take up water in a drying climate?Listen to Emeritus Professor Ulrich Zimmermann’s talk which was given at the Distinguished visitor Seminar on the 22st February, 2011.

The traditional paradigm of how plants take up water from the soil and transport it to the leaves is that water is pulled exclusively by transpiration-induced negative pressure gradients through continuous water columns. Water under negative pressure is in a metastable state. Cavitation is therefore a frequent event and can be catastrophic to water transport during drought. I will show how plants use other forces (such as gel-supported and interfacial forces) in order to overcome drought-induced interruption of the water columns. Evidence for this comes from non-invasive and minimally invasive techniques, such as NMR imaging, xylem probe and cell turgor probe, applied to crop and (fruit) trees. NMR imaging and non-invasive probes have also provided evidence that moisture uptake from the atmosphere by mucilage-containing epistomatal plugs plays an important role in the water supply of leaves of crop (such as grapevine and tomato), but also of 60-m tall trees. The results challenge our current view about the mechanism of water transport in plants and have paved the way for the development of new tools for online monitoring the water supply of crop under field conditions.

Short Speaker Biography

Currently, Emeritus Professor Ulrich Zimmermann is Senior Professor at the Biocenter of the University of Würzburg and chair of the scientific advisory board of ZIM Plant Technology. He was Head of the Membrane Research Group at the Research Center Jülich, Germany (1969-1984), and from 1984 – 2009 led the Department of Biotechnology at the University of Würzburg, Germany. The main focus of his research includes water transport and salt tolerance of plants and development of irrigation systems, biophysics of membrane transport, electromanipulation of cells and organelles, and turgor-mediated processes in algae and higher plants. He has authored c. 500 publications and more than 120 patents. Some of his most important inventions, which are used worldwide, include the plant cell turgor probe, xylem pressure probe and the magnetic, non-invasive probe for measuring turgor in leafy plants.