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Abstract Detail



Developmental and Structural Section

Schulte, Paul J. [1].

Computational models of two-phase flow in studies of cavitation and air-seeding in xylem vascular conduits.

The occurrence of cavitation events leading to embolism of vascular conduits in plants is an important aspect of maintaining the xylem transport pathway. The cavitation process is thought to involve air-seeding, whereby air bubbles spread through pits between tracheids or vessel elements. Studies of flow and associated hydraulic resistances have utilized computational approaches, but considering the spread of air requires a two-phase approach. Such methods treat both phases as immiscible liquids, where one can be a liquid and the other a gas. The interface between these phases will incorporate surface tension. This modeling approach was used to predict air spread through narrow openings between conduits like pits. As predicted from theory, greater pressure difference is needed for narrower pits. However the depth of the pore was also important, as shallow pores did not allow for the development of a low meniscus contact angle with the wall and therefore less pressure was required to force air through the opening. For a network of cells, it became apparent that air entry into a water-filled cell occurs over very short time scales (micro to milliseconds). Furthermore, the air entry increases the pressure in the liquid phase of the cell, suggesting that the increased pressure gradient across other cells in the network might, in the case of tracheids with torus-margo pits, be enough to seal the pit before the actual air-water interface reaches the margo pores of the pit.


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1 - University Of Nevada, Las Vegas, Life Sciences, 4505 S Maryland Pkwy, Las Vegas, NV, 89154-4004, USA

Keywords:
xylem
cavitation
air-seeding
hydraulic.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Hall D/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 5:30 PM
Number: PDS004
Abstract ID:595
Candidate for Awards:None


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