Polar auxin transport in relation to long-distance transport of nutrients in the Charales

Raven, JA

Polar auxin transport in relation to long-distance transport of nutrients in the Charales

Raven, JA

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Publication Type:: Journal Article
Citation:: Journal of Experimental Botany, 2013, 64 (1), pp. 1 - 9
Issue Date:: 2013-01-01

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Field	Value	Language
dc.contributor.author	Raven, JA https://orcid.org/0000-0002-2789-3297	en_US
dc.date.issued	2013-01-01	en_US
dc.identifier.citation	Journal of Experimental Botany, 2013, 64 (1), pp. 1 - 9	en_US
dc.identifier.issn	0022-0957	en_US
dc.identifier.uri	http://hdl.handle.net/10453/30715
dc.description.abstract	This paper examines the significance of the recent demonstration of polar auxin transport (PAT) in the green macroalga Chara (Charophyceae: Charales) and, especially, options for explaining some features of PAT in the Charales. The occurrence of PAT in the Charales shows that PAT originated in the algal ancestors of the embryophytes (liverworts, mosses, hornworts, and vascular plants), although it is not yet known if PAT occurs elsewhere in the Charophyceae or in other algae. While in the embryophytes PAT occurs in parenchymatously constructed structures which commonly also have xylem and phloem (or their bryophyte analogues) as long-distance transport processes in parallel to PAT, in Chara corallina PAT shares the pathway for long-distance transport of nutrients though the parenchymatously constructed nodal complexes and the single giant cells of the internode. The speed of auxin movement of PAT is much more rapid than that attributable to diffusion and of the same order as the rate of cytoplasmic streaming in the giant internodal cells, yet complete inhibition of streaming by the inhibitor cytochalasin H does not slow down auxin transport. Explanations for this phenomenon are sought in the operation of other mechanochemical motors, dynein-tubulin and kinesin-tubulin, as alternatives to the myosin-actin system which powers cytoplasmic streaming. Experiments in which microtubules are disrupted, for example by colchicine, could show if one of the tubulin-based motors is involved. If these motors are involved, some mechanism is needed to amplify the speeds known for the motors to explain the order of magnitude higher speeds seen for auxin transport. © 2012 The Author. Published by Oxford University Press [on behalf of the Society for Experimental Biology]. All rights reserved.	en_US
dc.relation.ispartof	Journal of Experimental Botany	en_US
dc.relation.isbasedon	10.1093/jxb/ers358	en_US
dc.subject.classification	Plant Biology & Botany	en_US
dc.subject.mesh	Chara	en_US
dc.subject.mesh	Indoleacetic Acids	en_US
dc.subject.mesh	Plant Growth Regulators	en_US
dc.subject.mesh	Chlorophyta	en_US
dc.title	Polar auxin transport in relation to long-distance transport of nutrients in the Charales	en_US
dc.type	Journal Article
utslib.citation.volume	1	en_US
utslib.citation.volume	64	en_US
utslib.for	0602 Ecology	en_US
utslib.for	0604 Genetics	en_US
utslib.for	0607 Plant Biology	en_US
utslib.for	0703 Crop and Pasture Production	en_US
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
utslib.copyright.status	closed_access
pubs.issue	1	en_US
pubs.publication-status	Published	en_US
pubs.volume	64	en_US

Abstract:

This paper examines the significance of the recent demonstration of polar auxin transport (PAT) in the green macroalga Chara (Charophyceae: Charales) and, especially, options for explaining some features of PAT in the Charales. The occurrence of PAT in the Charales shows that PAT originated in the algal ancestors of the embryophytes (liverworts, mosses, hornworts, and vascular plants), although it is not yet known if PAT occurs elsewhere in the Charophyceae or in other algae. While in the embryophytes PAT occurs in parenchymatously constructed structures which commonly also have xylem and phloem (or their bryophyte analogues) as long-distance transport processes in parallel to PAT, in Chara corallina PAT shares the pathway for long-distance transport of nutrients though the parenchymatously constructed nodal complexes and the single giant cells of the internode. The speed of auxin movement of PAT is much more rapid than that attributable to diffusion and of the same order as the rate of cytoplasmic streaming in the giant internodal cells, yet complete inhibition of streaming by the inhibitor cytochalasin H does not slow down auxin transport. Explanations for this phenomenon are sought in the operation of other mechanochemical motors, dynein-tubulin and kinesin-tubulin, as alternatives to the myosin-actin system which powers cytoplasmic streaming. Experiments in which microtubules are disrupted, for example by colchicine, could show if one of the tubulin-based motors is involved. If these motors are involved, some mechanism is needed to amplify the speeds known for the motors to explain the order of magnitude higher speeds seen for auxin transport. © 2012 The Author. Published by Oxford University Press [on behalf of the Society for Experimental Biology]. All rights reserved.

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http://hdl.handle.net/10453/30715