Taylor dispersion in osmotically driven laminar flows in phloem
Abstract
Sucrose is among the main products of photosynthesis that are deemed necessary for
plant growth and survival. It is produced in the mesophyll cells of leaves and translocated
to different parts of the plant through the phloem. Progress in understanding this
transport process remains fraught with experimental difficulties, thereby prompting
interest in theoretical approaches and laboratory studies. The Münch pressure and
mass flow model is one of the accepted hypotheses describing the physics of sucrose
transport in the phloem. It is based on osmosis creating an energy potential difference
between the source and the sink. The flow responding to this energy potential is assumed
laminar and described by the Hagen-Poiseuille equation. This study revisits such osmotically
driven flows in tubes with membrane walls by including the effects of Taylor dispersion
on mass transport. This effect has been overlooked in phloem flow studies. Taylor
dispersion can increase the effective transport of solutes by increasing the apparent
diffusion coefficient. It is shown that, in addition to the conventional diffusive
correction derived for impermeable tube walls, a new adjustment to the mean advective
terms arises because of osmotic effects. Because the molecular Schmidt number is very
large for sucrose in water, the sucrose front speed and travel times have a direct
dependence on the Péclet number for different ranges of the Münch number. This study
establishes upper limits on expected Taylor dispersion enhancement of sucrose transport.
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https://hdl.handle.net/10161/23397Published Version (Please cite this version)
10.1017/jfm.2021.56Publication Info
Nakad, M; Witelski, T; Domec, JC; Sevanto, S; & Katul, G (2021). Taylor dispersion in osmotically driven laminar flows in phloem. Journal of Fluid Mechanics, 913. 10.1017/jfm.2021.56. Retrieved from https://hdl.handle.net/10161/23397.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Jean Christophe Domec
Visiting Professor in the Nicholas School of the Environment
Bordeaux Sciences Agro in FRANCE (primary appointment)Discovery of knowledge in Plant
water relations, ecosystem ecology and ecohydrology, with special focus on: - Long-distance
water transport under future climate; - Drought tolerance and avoidance; - Patterns
of changes in structural and functional traits within individual plants. My goal as
a researcher is to improve the fundamental science understanding of how plants and
terrestrial ecosystems respond to climate
Gabriel G. Katul
George Pearsall Distinguished Professor
Gabriel G. Katul received his B.E. degree in 1988 at the American University of Beirut
(Beirut, Lebanon), his M.S. degree in 1990 at Oregon State University (Corvallis,
OR) and his Ph.D degree in 1993 at the University of California in Davis (Davis, CA).
He currently holds a distinguished Professorship in Hydrology and Micrometeorology
at the Department of Civil and Environmental Engineering at Duke University (Durham,
NC). He was a visiting fellow
Thomas P. Witelski
Professor in the Department of Mathematics
My primary area of expertise is the solution of nonlinear ordinary and partial differential
equations for models of physical systems. Using asymptotics along with a mixture of
other applied mathematical techniques in analysis and scientific computing I study
a broad range of applications in engineering and applied science. Focuses of my work
include problems in viscous fluid flow, dynamical systems, and industrial applications.
Approaches for mathematical modelling to formulate reduced systems o
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