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United States Department of Agriculture

Agricultural Research Service

Research Project: SUSTAINABLE VINEYARD PRODUCTION SYSTEMS

Location: Crops Pathology and Genetics Research

Title: Dynamics of embolism repair in xylem: in vivo visualizations using High Resolution Computed Tomography

Authors
item Broderson, Craig -
item MCELRONE, ANDREW
item Choat, Brendan -
item Matthews, Mark -
item Shackel, Ken -

Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 1, 2010
Publication Date: November 1, 2010
Repository URL: http://www.plantphysiol.org/content/154/3/1088.full
Citation: Broderson, C.R., Mcelrone, A.J., Choat, B., Matthews, M.A., Shackel, K. 2010. Dynamics of embolism repair in xylem: in vivo visualizations using High Resolution Computed Tomography. Plant Physiology. 154(3):1088-1095.

Interpretive Summary: Water moves through plants under tension and in a thermodynamically metastable state, leaving the non-living vessels that transport this water vulnerable to blockage by gas embolisms. Failure to re-establish flow in embolized vessels can lead to systemic loss of hydraulic conductivity and ultimately death. Most plants have developed a mechanism to restore vessel functionality by refilling embolized vessels, but the details of this process in vessel networks under tension have remained unclear for decades. Here we present the first in vivo visualization and quantification of the refilling process for any species using high resolution x-ray computed tomography. Successful vessel refilling in grapevine (Vitis vinifera) was dependent on water influx from surrounding living tissue at a rate of 6*10**-4 µm s**-1, with individual droplets expanding over time, filling vessels, and forcing the dissolution of entrapped gas. Both filling and draining processes could be observed in the same vessel, indicating that successful refilling requires hydraulic isolation from tensions that would otherwise prevent embolism repair. Our study demonstrates that despite the presence of tensions in the bulk xylem, plants are able to restore hydraulic conductivity in the xylem.

Technical Abstract: Water moves through plants under tension and in a thermodynamically metastable state, leaving the non-living vessels that transport this water vulnerable to blockage by gas embolisms. Failure to re-establish flow in embolized vessels can lead to systemic loss of hydraulic conductivity and ultimately death. Most plants have developed a mechanism to restore vessel functionality by refilling embolized vessels, but the details of this process in vessel networks under tension have remained unclear for decades. Here we present the first in vivo visualization and quantification of the refilling process for any species using high resolution x-ray computed tomography. Successful vessel refilling in grapevine (Vitis vinifera) was dependent on water influx from surrounding living tissue at a rate of 6*10**-4 µm s**-1, with individual droplets expanding over time, filling vessels, and forcing the dissolution of entrapped gas. Both filling and draining processes could be observed in the same vessel, indicating that successful refilling requires hydraulic isolation from tensions that would otherwise prevent embolism repair. Our study demonstrates that despite the presence of tensions in the bulk xylem, plants are able to restore hydraulic conductivity in the xylem.

Last Modified: 9/29/2014
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