The Choat Lab

Plant Hydraulics and Water Relations

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Visit from Herve Cochard

Herve, Rosana and Brendan at Mt Banks NP, NSW

Herve, Rosana and Brendan at Mt Banks, NSW

We were lucky enough to receive a visit from Dr Herve Cochard, aka “The General” of INRA. Herve, a world leader in plant hydraulics, is a close collaborator with the lab and a co-sponsor of Rosana’s Marie Curie Fellowship. Here we are at Mt Banks in the Blue Mountains NP, NSW.

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Hydraulic vulnerability analysis using X-ray microCT

One of the major points of critique for hydraulic measurements of xylem vulnerability and embolism is that they are destructive measurements. In contrast, non-invasive imaging has made it possible to observe xylem function and the spread of embolism in living, intact plants without destructive sampling and associated artefacts.

In collaboration with Iain Young and Richard Flavel at the University of New England, Armidale, we recently scanned the stems of young Eucalyptus trees at high resolution using X-ray Micro Computed Tomography (microCT) to visualize the loss of hydraulic function at increasing levels of drought. This allowed us to analyse the species’ vulnerability to drought-induced embolism, and validate hydraulic data using an independent, non-destructive method.

MicroCT cross section of a Eucalyptus stem in which air-filled areas appear darker than water-saturated tissues. From the centre outwards, you can see the central pith and primary xylem, followed by a ring of embolised vessels in the outer xylem area.

MicroCT cross section of a Eucalyptus stem.

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