Magnetic resonance imaging of water ascent in embolized xylem vessels of grapevine stem segments

Wang, M., Tyree, M. T. and Wasylishen, R. E. 2013. Magnetic resonance imaging of water ascent in embolized xylem vessels of grapevine stem segments. Can. J. Plant Sci. 93: 879-893. Temporal and spatial information about water refilling of embolized xylem vessels and the rate of water ascent in these vessels is critical for understanding embolism repair in intact living vascular plants. High-resolution 1H magnetic resonance imaging (MRI) experiments have been performed on embolized grapevine stem segments while they were subjected to refilling at two different applied water pressures in order to investigate these important aspects of embolism repair. Magnetic resonance imaging difference images show that vessels located near the bark tend to refill faster than do inner ones, suggesting that vessel position within the cross section of the stem may affect the refilling process within the vessel. An MRI method for determining the water ascent velocity in each individual embolized xylem vessel is presented. At...