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Let’s not forget the critical role of surface tension in xylem water relations

Informally Refereed

Abstract

The widely supported cohesion–tension theory of water transport explains the importance of a continuous water column and the mechanism of long-distance ascent of sap in plants (Dixon 1914, Tyree 2003, Angeles et al. 2004). The evaporation of water from the surfaces of mesophyll cells causes the air–water interface to retreat into the cellulose matrix of the plant cell wall because the cohesion forces between water molecules are stronger than their attraction to air. As a result, the interface between the gas and liquid phases places the mass of water under negative pressure (tension). This pulling force is then transmitted to soil water via a continuous water column since the strong hydrogen bonding of the water molecules also allows water to stay liquid under tension (Oertli 1971). Related to these cohesive forces is surface tension, which characterizes how difficult it is to stretch the surface of a liquid.

Citation

Domec, Jean-Christophe. 2011. Let’s not forget the critical role of surface tension in xylem water relations. Tree Physiology 31:359-360.
https://www.fs.usda.gov/research/treesearch/38556