Annals of Botany

The temporal dynamics of xylem refilling and recovery from embolism in intact maize leaves

A direct observation of embolism repair in intact plants is essential in order to understand the mechanisms that regulate water transport in plants. Ryu et al. demonstrate rapid radial water-refilling and removal of gas bubbles in intact maize leaves, by X-ray micro-imaging of embolised xylem vessels.

Schematic of water refilling in an embolized xylem vessel.
Schematic of water refilling in an embolized xylem vessel. In the initial stage of water refilling (stage I), radial influx forms droplets on one side wall or both side walls of an embolized xylem vessel near the perforation plates. With continuous water supply in the radial direction, droplets merge into water columns (stage II). The volume of these individual water columns increases continuously; individual water columns also combine, forming a larger water column. In this process, the gas phase between the two water columns is dissolved in water. Water columns show vertical translational movement in xylem vessels (stage III).

Water refilling along the radial direction leads to rapid recovery from embolism within several minutes. These findings on the xylem refilling process in a well-watered plant could stimulate discussion on embolism repair mechanisms that are not osmotically driven in monocotyledon, herbaceous plants.

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