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<meta content="Brodribb, Tim J." name="eprints.creators_name" />
<meta content="Holbrook, N. M." name="eprints.creators_name" />
<meta content="Timothy.Brodribb@utas.edu.au" name="eprints.creators_id" />
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Leaf Vein of a Tropical Conifer" name="eprints.title" />
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<meta content="Just as a soggy paper straw is prone to yielding under the applied suction of a thirsty drinker, the xylem tracheids in leaves
seem prone to collapse as water potential declines, impeding their function. Here we describe the collapse, under tension, of
lignified cells peripheral to the leaf vein of a broad-leaved rainforest conifer, Podocarpus grayi de Laub. Leaves of Podocarpus
are characterized by an array of cylindrical tracheids aligned perpendicular to the leaf vein, apparently involved in the
distribution of water radially through the mesophyll. During leaf desiccation the majority of these tracheids collapsed from
circular to flat over the water potential range 21.5 to 22.8 MPa. An increase in the percentage of tracheids collapsed during
imposed water stress was mirrored by declining leaf hydraulic conductivity (Kleaf), implying a direct effect on water transport
efficiency. Stomata responded to water stress by closing at 22.0 MPa when 45% of cells were collapsed and Kleaf had declined
by 25%. This was still substantially before the initial indications of cavitation-induced loss of hydraulic conductance in the leaf
vein, at 23 MPa. Plants droughted until 49% of tracheids had collapsed were found to fully recover tracheid shape and leaf
function 1 week after rewatering. A simple mechanical model of tracheid collapse, derived from the theoretical buckling
pressure for pipes, accurately predicted the collapse dynamics observed in P. grayi, substantiating estimates of cell wall
elasticity and measured leaf water potential. The possible adaptive advantages of collapsible vascular tissue are discussed." name="eprints.abstract" />
<meta content="2005" name="eprints.date" />
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tion: correlation with other leaf physiological traits. Plant Physiol 132:
2166–2173
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conductance in a tropical tree species. Plant Cell Environ 27:
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failure: a comparison of coexisting ferns and angiosperms. New Phytol
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Brodribb and Holbrook
1146" name="eprints.referencetext" />
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<meta content="Just as a soggy paper straw is prone to yielding under the applied suction of a thirsty drinker, the xylem tracheids in leaves
seem prone to collapse as water potential declines, impeding their function. Here we describe the collapse, under tension, of
lignified cells peripheral to the leaf vein of a broad-leaved rainforest conifer, Podocarpus grayi de Laub. Leaves of Podocarpus
are characterized by an array of cylindrical tracheids aligned perpendicular to the leaf vein, apparently involved in the
distribution of water radially through the mesophyll. During leaf desiccation the majority of these tracheids collapsed from
circular to flat over the water potential range 21.5 to 22.8 MPa. An increase in the percentage of tracheids collapsed during
imposed water stress was mirrored by declining leaf hydraulic conductivity (Kleaf), implying a direct effect on water transport
efficiency. Stomata responded to water stress by closing at 22.0 MPa when 45% of cells were collapsed and Kleaf had declined
by 25%. This was still substantially before the initial indications of cavitation-induced loss of hydraulic conductance in the leaf
vein, at 23 MPa. Plants droughted until 49% of tracheids had collapsed were found to fully recover tracheid shape and leaf
function 1 week after rewatering. A simple mechanical model of tracheid collapse, derived from the theoretical buckling
pressure for pipes, accurately predicted the collapse dynamics observed in P. grayi, substantiating estimates of cell wall
elasticity and measured leaf water potential. The possible adaptive advantages of collapsible vascular tissue are discussed." name="DC.description" />
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<h1 class="ep_tm_pagetitle">Water Stress Deforms Tracheids Peripheral to the Leaf Vein of a Tropical Conifer</h1>
<p style="margin-bottom: 1em" class="not_ep_block"><span class="person_name">Brodribb, Tim J.</span> and <span class="person_name">Holbrook, N. M.</span> (2005) <xhtml:em>Water Stress Deforms Tracheids Peripheral to the Leaf Vein of a Tropical Conifer.</xhtml:em> Plant Physiology, 137 . pp. 1139-1146. ISSN 0032-0889</p><p style="margin-bottom: 1em" class="not_ep_block"></p><table style="margin-bottom: 1em" class="not_ep_block"><tr><td valign="top" style="text-align:center"><a href="http://eprints.utas.edu.au/2587/1/trachied__squish.pdf"><img alt="[img]" src="http://eprints.utas.edu.au/style/images/fileicons/application_pdf.png" class="ep_doc_icon" border="0" /></a></td><td valign="top"><a href="http://eprints.utas.edu.au/2587/1/trachied__squish.pdf"><span class="ep_document_citation">PDF</span></a> - Full text restricted - Requires a PDF viewer<br />223Kb</td><td><form method="get" accept-charset="utf-8" action="http://eprints.utas.edu.au/cgi/request_doc"><input accept-charset="utf-8" value="3394" name="docid" type="hidden" /><div class=""><input value="Request a copy" name="_action_null" class="ep_form_action_button" onclick="return EPJS_button_pushed( '_action_null' )" type="submit" /> </div></form></td></tr></table><p style="margin-bottom: 1em" class="not_ep_block">Official URL: <a href="http://dx.doi.org/10.1104/pp.104.058156">http://dx.doi.org/10.1104/pp.104.058156</a></p><div class="not_ep_block"><h2>Abstract</h2><p style="padding-bottom: 16px; text-align: left; margin: 1em auto 0em auto">Just as a soggy paper straw is prone to yielding under the applied suction of a thirsty drinker, the xylem tracheids in leaves
seem prone to collapse as water potential declines, impeding their function. Here we describe the collapse, under tension, of
lignified cells peripheral to the leaf vein of a broad-leaved rainforest conifer, Podocarpus grayi de Laub. Leaves of Podocarpus
are characterized by an array of cylindrical tracheids aligned perpendicular to the leaf vein, apparently involved in the
distribution of water radially through the mesophyll. During leaf desiccation the majority of these tracheids collapsed from
circular to flat over the water potential range 21.5 to 22.8 MPa. An increase in the percentage of tracheids collapsed during
imposed water stress was mirrored by declining leaf hydraulic conductivity (Kleaf), implying a direct effect on water transport
efficiency. Stomata responded to water stress by closing at 22.0 MPa when 45% of cells were collapsed and Kleaf had declined
by 25%. This was still substantially before the initial indications of cavitation-induced loss of hydraulic conductance in the leaf
vein, at 23 MPa. Plants droughted until 49% of tracheids had collapsed were found to fully recover tracheid shape and leaf
function 1 week after rewatering. A simple mechanical model of tracheid collapse, derived from the theoretical buckling
pressure for pipes, accurately predicted the collapse dynamics observed in P. grayi, substantiating estimates of cell wall
elasticity and measured leaf water potential. The possible adaptive advantages of collapsible vascular tissue are discussed.</p></div><table style="margin-bottom: 1em" cellpadding="3" class="not_ep_block" border="0"><tr><th valign="top" class="ep_row">Item Type:</th><td valign="top" class="ep_row">Article</td></tr><tr><th valign="top" class="ep_row">Subjects:</th><td valign="top" class="ep_row"><a href="http://eprints.utas.edu.au/view/subjects/270402.html">270000 Biological Sciences > 270400 Botany > 270402 Plant Physiology</a><br /><a href="http://eprints.utas.edu.au/view/subjects/270400.html">270000 Biological Sciences > 270400 Botany</a></td></tr><tr><th valign="top" class="ep_row">ID Code:</th><td valign="top" class="ep_row">2587</td></tr><tr><th valign="top" class="ep_row">Deposited By:</th><td valign="top" class="ep_row"><span class="ep_name_citation"><span class="person_name">Scholarly Publications Librarian</span></span></td></tr><tr><th valign="top" class="ep_row">Deposited On:</th><td valign="top" class="ep_row">29 Nov 2007 14:59</td></tr><tr><th valign="top" class="ep_row">Last Modified:</th><td valign="top" class="ep_row">09 Jan 2008 02:30</td></tr><tr><th valign="top" class="ep_row">ePrint Statistics:</th><td valign="top" class="ep_row"><a target="ePrintStats" href="/es/index.php?action=show_detail_eprint;id=2587;">View statistics for this ePrint</a></td></tr></table><p align="right">Repository Staff Only: <a href="http://eprints.utas.edu.au/cgi/users/home?screen=EPrint::View&eprintid=2587">item control page</a></p>
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