Functional repair of embolized vessels in maize roots after temporal drought stress, as demonstrated by magnetic resonance imaging

Author
Kaufmann, Ilja · Schulze-Till, Thomas · Schneider, Heike U. · Zimmermann, Ulrich · Jakob, Peter · Wegner, Lars H.
Published October 2009
Journal New Phytologist
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Abstract

Summary

Xylem sap under high tension is in a metastable state and tends to cavitate, frequently leading to an interruption of the continuous water columns. Mechanisms of cavitation repair are controversially discussed.

Magnetic resonance (MR) imaging provides a noninvasive, high spatial and temporal resolution approach to monitor xylem cavitation, refilling, and functionality.

Spin density maps of drought-stressed maize taproots were recorded to localize cavitation events and to visualize the refilling processes; c. 2 h after release of the nutrient solution from the homemade MR imaging cuvette that received the root, late metaxylem vessels started to cavitate randomly as identified by a loss of signal intensity. After c. 6 h plants were rewatered, leading to a repair of water columns in five out of eight roots. Sap ascent during refilling, monitored with multislice MR imaging sequences, varied between 0.5 mm min−1 and 3.3 mm min−1. Flow imaging of apparently refilled vessels was performed to test for functional repair. Occasionally, a collapse of xylem vessels under tension was observed; this collapse was reversible upon rewatering.

Refilling was an all-or-none process only observed under low-light conditions. Absence of flow in some of the apparently refilled vessels indicates that functionality was not restored in these particular vessels, despite a recovery of the spin density signal.

New Phytologist (2009) 184: 245-256

doi: 10.1111/j.1469-8137.2009.02919.x

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Details

Title
Functional repair of embolized vessels in maize roots after temporal drought stress, as demonstrated by magnetic resonance imaging
Author*
Kaufmann, Ilja · Schulze-Till, Thomas · Schneider, Heike U. · Zimmermann, Ulrich · Jakob, Peter · Wegner, Lars H.
Year
2009
Journal*
New Phytologist
Document Type*
Research article
Language*
eng
Subjects*
Cavitation · Collapse Of Xylem Vessels · Drought Stress · Flow Imaging · Magnetic Resonance (MR) Imaging (Microscopy) · Xylem Refilling · Zea Mays (Maize)

Fields edited by Q-Sensei or Q-Sensei's users are marked with an asterisk (*).
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