Author Correction: Passive water ascent in a tall, scalable synthetic tree

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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 ambient pressure, the water ascent velocity ranges from 0.0090 to 0.60 mm min−1, but increases to a range of 0.016 to 0.70 mm min−1 at 9.8 kPa above ambient pressure. A steady-state bubble model that offers analytical solutions of the water ascent velocity in embolized xylem vessels is presented; model calculations show that if other parameters are held constant, water ascent velocity is influenced by vessel diameter and position.

The Significance of the Accessory Tissues of the Hydrosystem for Osmotic Water Shifting as the Second Principle of Water Ascent, With Some Thoughts Concerning the Evolution of Trees

The accessory tissues of the hydrosystem consist of the parenchymatic contact tissue of the xylem rays, as weIl as the paratracheidal parenchyma in gymnosperms, and the paratracheal contact-parenchyma in angiosperms.