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Visualization of xylem embolism by X‐ray microtomography: a direct test against hydraulic measurements
Author(s) -
Nolf Markus,
Lopez Rosana,
Peters Jennifer M. R.,
Flavel Richard J.,
Koloadin Leah S.,
Young Iain M.,
Choat Brendan
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14462
Subject(s) - xylem , x ray microtomography , visualization , embolism , biology , materials science , botany , computer science , physics , artificial intelligence , medicine , optics , cardiology
Summary X‐ray microtomography (micro CT ) is becoming a valuable noninvasive tool for advancing our understanding of plant–water relations. Laboratory‐based micro CT systems are becoming more affordable and provide better access than synchrotron facilities. However, some systems come at the cost of comparably lower signal quality and spatial resolution than synchrotron facilities. In this study, we evaluated laboratory‐based X‐ray micro CT imaging as a tool to nondestructively analyse hydraulic vulnerability to drought‐induced embolism in a woody plant species. We analysed the vulnerability to drought‐induced embolism of benchtop‐dehydrated Eucalyptus camaldulensis plants using micro CT and hydraulic flow measurements on the same sample material, allowing us to directly compare the two methods. Additionally, we developed a quantitative procedure to improve micro CT image analysis at limited resolution and accurately measure vessel lumens. Hydraulic measurements matched closely with micro CT imaging of the current‐year growth ring, with similar hydraulic conductivity and loss of conductivity due to xylem embolism. Optimized thresholding of vessel lumens during image analysis, based on a physiologically meaningful parameter (theoretical conductivity), allowed us to overcome common potential constraints of some lab‐based systems. Our results indicate that estimates of vulnerability to embolism provided by micro CT visualization agree well with those obtained from hydraulic measurements on the same sample material.