Scaling Phloem Transport: Water Potential Equilibrium and Osmoregulatory Flow

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Scaling Phloem Transport: Water Potential Equilibrium and Osmoregulatory Flow

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dc.contributor.author Holbrook, Noel
dc.contributor.author Thompson, Matthew
dc.date.accessioned 2009-06-08T17:49:55Z
dc.date.issued 2003
dc.identifier.citation Thompson, Matthew V., and N. Michele Holbrook. 2003. Scaling phloem transport: water potential equilibrium and osmoregulatory flow. Plant Cell and Environment 26 (9):1561-1577. en
dc.identifier.issn 1365-3040 en
dc.identifier.issn 0140-7791 en
dc.identifier.uri http://nrs.harvard.edu/urn-3:HUL.InstRepos:3043428
dc.description.abstract In this work, the common assumption that phloem sap is in water potential equilibrium with the surrounding apoplast was examined. With a dimensionless model of phloem translocation that scales with just two dimensionless parameters ((R) over cap and (F) over cap), a 'map' of phloem behaviour as a function of these parameters was produced, which shows that the water potential equilibrium assumption ((R) over cap(F) over cap >> 1) is valid for essentially all realistic values of the relevant scales. When in water potential equilibrium, a further parameter reduction is possible that limits model dependence to a single parameter ((F) over cap), which describes the ratio of the solution's osmotic strength to its axial pressure drop. Due to the locally autonomous nature of individual sieve element/companion cell complexes, it is argued that long-distance integrative control is most efficient when is large ( that is, when the pressure drop is relatively small), permitting the sieve tube to regulate solute loading in response to global changes in turgor. This mode of transport has been called 'osmoregulatory flow.' Limitations on the pressure drop within the transport phloem could require that sieve tubes be shorter than the long axis of the plant, and thus arranged in series and hydraulically isolated from one another. en
dc.description.sponsorship Organismic and Evolutionary Biology en
dc.language.iso en_US en
dc.publisher Blackwell Publishing en
dc.relation.isversionof http://dx.doi.org/10.1046/j.1365-3040.2003.01080.x en
dash.license META_ONLY
dc.subject geometry en
dc.subject relay en
dc.subject map en
dc.subject sieve tube en
dc.subject dimensionless parameters en
dc.subject plate en
dc.subject dimensional analysis en
dc.title Scaling Phloem Transport: Water Potential Equilibrium and Osmoregulatory Flow en
dc.relation.journal Plant Cell and Environment en
dash.depositing.author Holbrook, Noel
dash.embargo.until 10000-01-01

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  • FAS Scholarly Articles [6948]
    Peer reviewed scholarly articles from the Faculty of Arts and Sciences of Harvard University

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