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supported by Australian Research Council and Landcare Research NZ |
6th October 2009, at Macquarie University, Sydney. |
SPEAKERS INCLUDE |
On Tuesday 6th October there will be an intensive 1-day research course offered, open to interested researchers and ECR and HDR.
The purpose of the remainder of the week for working group participants will be to synthesize available anatomical and physiological data relevant to hydraulic trade-offs. This is aimed specifically at advancing our fundamental understanding of xylem function and also at providing a database for broad ecological analyses of interaction between xylem traits and environment.
Background
Plants routinely face xylem tensions great enough to cause cavitation and embolism, a problem exacerbated by environmental stresses such as drought, freezing and salinity. Embolism reduces the capacity of the xylem tissue to deliver water to sites of gas exchange and can therefore impact the ability of the plant to maintain a net positive carbon balance. In the extreme, xylem embolism can reach lethal levels causing branch die back and ultimately plant death. Since it is crucial to the survival of plants that the risk of extensive cavitation and embolism in the xylem is minimized, there is significant evidence for structure-functional trade-offs between hydraulic efficiency and safety from cavitation, indicating that variation in hydraulic traits is central to the ability of plants to balance water loss and carbon gain across a range of environments.
However, in a meta-analysis of literature data, Maherali et al. (2004) found only a weak relationship between sapwood specific hydraulic conductivity (KS, conductivity per unit of cross-sectional sapwood area) and P50-values (the xylem tension at which 50% of the maximum hydraulic conductivity is lost). The relationship between KS and P50 was found to be primarily driven by the structural difference between conifers and angiosperms. This raises interesting questions:
- How strong or weak are Ks vs. P50 relationships at various taxonomic levels (e.g. angiosperms vs. gymnosperms, vesselless vs. vesselled angiosperms, within a particular family) or for plant species growing in similar/diverse environmental conditions or with similar biogeographic history?
- Why do some species perform poorly in terms of both hydraulic efficiency as well as safety? Do these “incompetent” species show any particular wood anatomical characteristics in common?
- To what extent do similar hydraulic demands and/or similar environmental conditions influence wood anatomical variation and vice versa?
- It is clear that interpretations based on various datasets have some structure-functional patterns in common, but also show interesting differences. Will trends found for a particular taxonomic group of species or for plants from a particular vegetation type also hold up if datasets are analysed all together?
Mark Westoby |
Opening address and welcome: Veg function network |
8:50 - 9:00 |
Brendan Choat |
Hydraulic traits and the distribution of plant species |
9:00-9:20 |
Ian Wright |
Cross-species patterns in the coordination between leaf and stem hydraulics traits |
9:20-9:40 |
Amy Zanne |
Hydraulic safety and efficiency traits in Australian angiosperms |
9:40-10:00 |
Mark Westoby |
Plant ecological strategies: the relevance of xylem functional traits |
10:00-10:20 |
Morning tea |
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10:20-10:40 |
Jarmila Pittermann |
Hydraulic trade-offs associated with cavitation resistance in conifers: a pit level perspective |
10:40-11:00 |
Jordi Martinez-Vilalta |
Water transport and the spatial arrangement of xylem networks |
11:20-11:40 |
Sylvain Delzon |
New insights into the mechanism of water-stress induced cavitation in conifers |
11:40-12:00 |
Lunch |
|
12:00-1:00 |
Steven Jansen |
Systematic, ecological, and functional aspects of bordered pits in the hydraulic network of plants |
1:00-1:20 |
Sandra Bucci |
Functional convergence of hydraulic traits in tropical trees |
1:20-1:40 |
Taylor Feild |
Hydraulic traits and vessel evolution in early angiosperms |
1:40-2:00 |
Radika Bhaskar |
Evolution of hydraulic traits in closely related species pairs from North America |
2:00-2:20 |
Afternoon tea |
|
2:20-2:40 |
Tim Brodribb |
Constraints of xylem hydraulic physiology on terrestrial plant productivity |
2:40-3:00 |
Pat Mitchell |
Hydraulic functional types in south-western Australia |
3:00-3:20 |
Herve Cochard |
Rapid measurement of xylem cavitation resistance as a criterion for screening drought resistance |
3:20-3:40 |
Sean Gleason |
Hydraulic traits of Australian tropical plants. |
3:40-4:00 |
Last Updated September 2009
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