| Abstract Detail
Physiology Schenk, H. Jochen [1], Mocko, Kerri [1], Michaud, Joseph M. [1], Garcia Mora, Jessica [1], Kaack, Lucian [2], Guan, Xinyi [2], Roth, Mary R. [3], Welti, Ruth A. [3], Jansen, Steven [2]. Interfacial phenomena in plant xylem, a system under negative pressure. The xylem of vascular plants is unique in that it is the only compartment in living organisms that often operates under metastable negative pressure conditions. Many attempts have been made to explain how negative pressure can be sustained in a complex hydraulic system without causing rampant bubble formation, but experimental and modeling approaches to answer this question have been largely based on highly simplified and inaccurate assumptions about the actual conditions in xylem. To address the need for better empirical observations of xylem, especially of the gas-liquid and liquid-solid interfaces, where gas bubbles are most likely to originate, we assembled an interdisciplinary team of researchers at several institutions to study the chemistry and structure of vessel surfaces in woody plants across the angiosperm phylogeny using transmission electron microscopy, confocal, and atomic force microscopy, analyze the chemistry of surface-active lipids in xylem via mass spectrometry, and their surface activity via axisymmetric drop shape analysis of constrained sessile drops. Because the behavior of xylem lipids under negative pressure has never been explored, we conducted molecular dynamics simulations to test how lipid bilayers and micelles in water behave under negative pressure. The findings point to a key role of surface-active, phospho- and galactolipids in xylem water transport, a conclusion that is supported by findings of apoplastic lipids in all gymnosperms, ferns, cycads, and mosses tested so far. Surfaces and surface-active molecules in xylem deserve much more attention than they have received to date, and more realistic models, including artificial systems, are needed to explore the behavior of interfacial surfaces under negative pressure.
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Related Links:
Plants & H2O Lab website
1 - California State University Fullerton, Department Of Biological Science, PO Box 6850, Fullerton, CA, 92834, United States
2 - Institute Of Systematic Botany And Ecology, Albert-Einstein-Allee 11, Ulm University, Ulm, BW, D-89081, Germany
3 - Kansas State University, Kansas Lipidomics Research Center, Division of Biology, Ackert Hall, 1717 Claflin Rd., Manhattan, KS, 66506, USA
Keywords:
xylem
polar lipids
water transport.
Presentation Type: Oral Paper
Session: PHYS, Physiology
Location: /
Date: Wednesday, July 21st, 2021
Time: 10:45 AM(EDT)
Number: PHYS004
Abstract ID:280
Candidate for Awards:None |
