title: Nanobubbles: a new paradigm for air-seeding in xylem.
abstract: Long-distance water transport in plants relies on a system that typically operates under negative pressure and is prone to hydraulic failure due to gas bubble formation. One primary mechanism of bubble formation takes place at nanoporous pit membranes between neighboring conduits. We argue that this process is likely to snap off nanobubbles because the local increase in liquid pressure caused by entry of air-water menisci into the complex pit membrane pores would energetically favor nanobubble formation over instant cavitation. Nanobubbles would be stabilized by surfactants and by gas supersaturation of the sap, may dissolve, fragment into smaller bubbles, or create embolisms. The hypothesis that safe and stable nanobubbles occur in plants adds a new component supporting the cohesion-tension theory.
authors: Department of Biological Science, California State University Fullerton, PO Box 6850, Fullerton, CA 92834-6850, USA.
authors: H Jochen
authors: HJ
authors: Schenk
authors: Laboratory of Plant Ecology, Department of Applied Ecology and Environmental Biology, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
authors: Kathy
authors: K
authors: Steppe
authors: Institute for Systematic Botany and Ecology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany. Electronic address: steven.jansen@uni-ulm.de.
authors: Steven
authors: S
authors: Jansen
mesh_terms: D001692:Biological Transport; D010944:Plants / Q000378:metabolism*; D011312:Pressure; D014867:Water / Q000378:metabolism*; D052584:Xylem / Q000378:metabolism*
chemical_list: D014867:Water
keywords: Blake threshold; cohesion tension theory; nanobubbles; surfactants; xylem embolisms