TY  - JOUR
AU  - Kaufmann, I.
AU  - Schulze-Till, T.
AU  - Schneider, H. U.
AU  - Zimmermann, U.
AU  - Jakob, P.
AU  - Wegner, L. H.
TI  - Functional repair of embolized vessels in maize roots after temporal drought stress, as demonstrated by magnetic  resonance imaging
JO  - The new phytologist
VL  - 184
SN  - 0028-646X
CY  - Oxford [u.a.]
PB  - Wiley-Blackwell
M1  - PreJuSER-964
SP  - 245 - 256
PY  - 2009
N1  - Record converted from VDB: 12.11.2012
AB  - 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.
KW  - Droughts
KW  - Magnetic Resonance Spectroscopy
KW  - Models, Biological
KW  - Plant Exudates: metabolism
KW  - Plant Roots: cytology
KW  - Plant Roots: physiology
KW  - Plant Transpiration
KW  - Seedling: physiology
KW  - Spin Labels
KW  - Stress, Physiological
KW  - Time Factors
KW  - Xylem: physiology
KW  - Zea mays: physiology
KW  - Plant Exudates (NLM Chemicals)
KW  - Spin Labels (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:19563443
UR  - <Go to ISI:>//WOS:000269541600023
DO  - DOI:10.1111/j.1469-8137.2009.02919.x
UR  - https://juser.fz-juelich.de/record/964
ER  -