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In vivo visualization of the final stages of xylem vessel refilling in grapevine ( Vitis vinifera ) stems
Author(s) -
Brodersen Craig R.,
Knipfer Thorsten,
McElrone Andrew J.
Publication year - 2018
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.14811
Subject(s) - xylem , vitis vinifera , perforation , tortuosity , water transport , lumen (anatomy) , anatomy , materials science , biology , botany , composite material , water flow , geology , porosity , microbiology and biotechnology , soil science , punching
Summary Embolism removal is critical for restoring hydraulic pathways in some plants, as residual gas bubbles should expand when vessels are reconnected to the transpiration stream. Much of our understanding of embolism removal remains theoretical as a consequence of the lack of in vivo images of the process at high magnification. Here, we used in vivo X‐ray micro‐computed tomography (micro CT ) to visualize the final stages of xylem refilling in grapevine ( Vitis vinifera ) paired with scanning electron microscopy. Before refilling, vessel walls were covered with a surface film, but vessel perforation plate openings and intervessel pits were filled with air. Bubbles were removed from intervessel pits first, followed by bubbles within perforation plates, which hold the last volumes of air which eventually dissolve. Perforation plates were dimorphic, with more steeply angled scalariform plates in narrow diameter vessels, compared with the simple perforation plates in older secondary xylem, which may favor rapid refilling and compartmentalization of embolisms that occur in small vessels, while promoting high hydraulic conductivity in large vessels. Our study provides direct visual evidence of the spatial and temporal dynamics of the final stages of embolism removal.