<!DOCTYPE html>
<html class="client-nojs vector-feature-night-mode-disabled vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-sticky-header-enabled" lang="en" dir="ltr"><head>
<meta charset="UTF-8">
<title>Root cap</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<link rel="canonical" href="https://en.wikipedia.org/wiki/Root_cap"> <link href="./mw/ext.cite.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.icons.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.search.codex.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/skins.vector.styles.css" rel="stylesheet" type="text/css">
<link href="./mw/user.styles.css" rel="stylesheet" type="text/css">
<meta name="ResourceLoaderDynamicStyles" content="">
<link rel="stylesheet" type="text/css" href="./mw/site.styles.css">
<link rel="stylesheet" type="text/css" href="./mw/noscript.css">
<link rel="stylesheet" type="text/css" href="./footer.css">
<link rel="stylesheet" type="text/css" href="./vector-2022.css">
</head>
<body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject page-Root_cap rootpage-Root_cap skin-vector-2022 action-view">
<div class="mw-page-container">
<div class="mw-page-container-inner">
<div class="mw-content-container">
<main id="content" class="mw-body">
<header class="mw-body-header vector-page-titlebar">
<h1 id="firstHeading" class="firstHeading mw-first-heading">
<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Root cap</span></span>
</h1>
</header>
<a id="top"></a>
<div id="bodyContent" class="vector-body ve-init-mw-desktopArticleTarget-targetContainer" aria-labelledby="firstHeading" data-mw-ve-target-container="">
<div id="mw-content-text" class="mw-body-content mw-content-ltr" lang="en" dir="ltr"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr">
<p>The <b>root cap</b> (also called the <b>calyptra</b>) is a small but multitasking organ that covers the very tip of every growing plant <a href="Root" title="Root">root</a>. It shields the delicate <a href="Apical_meristem" class="mw-redirect" title="Apical meristem">apical meristem</a> from mechanical damage, lubricates the root's passage through soil, and houses specialised <a href="Gravitropism" title="Gravitropism">gravity-sensing</a> cells that guide the root's overall direction of growth.
</p>
<meta property="mw:PageProp/toc">
<div class="mw-heading mw-heading2"><h2 id="Structure_and_function">Structure and function</h2></div>
<p>Root caps contain <a href="Statocyte" title="Statocyte">statocytes</a> (<a href="Gravitropism" title="Gravitropism">gravity-sensing</a> cells) whose dense statoliths settle in response to gravity; if the cap is carefully removed a root loses its orientation and grows at random. The cap also secretes a layer of <a href="Mucilage" title="Mucilage">mucilage</a> that reduces friction and may foster signalling with the surrounding soil <a href="Microbiota" title="Microbiota">microbiota</a>.<sup id="cite_ref-Raven_&_Edwards_2001_1-0" class="reference"><a href="#cite_note-Raven_&_Edwards_2001-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> Because of its sensor cells, the organ underpins <a href="Gravitropism" title="Gravitropism">gravitropism</a> (sometimes called geoperception), helping the root grow downwards with gravity or reorient upwards against it.<sup id="cite_ref-Burgess_1985_2-0" class="reference"><a href="#cite_note-Burgess_1985-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Kuya_&_Sato_2011_3-0" class="reference"><a href="#cite_note-Kuya_&_Sato_2011-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading2"><h2 id="Development_and_turnover">Development and turnover</h2></div>
<p>The root cap is renewed continuously. Stem-cell files on its inner face divide to generate successive layers of <a href="Columella_(botany)" title="Columella (botany)">columella</a> and lateral root-cap cells; as the root advances, the oldest outer layers are sloughed off so the organ maintains a steady size. In <a href="Cereal" title="Cereal">cereals</a> and many <a href="Legume" title="Legume">legumes</a> these discarded layers separate as long-lived "border cells", whereas in <i><a href="Arabidopsis_thaliana" title="Arabidopsis thaliana">Arabidopsis thaliana</a></i> most surface cells undergo rapid, developmentally-<a href="Programmed_cell_death" title="Programmed cell death">programmed cell death</a> before shedding.<sup id="cite_ref-Kumpf_&_Nowack_2015_4-0" class="reference"><a href="#cite_note-Kumpf_&_Nowack_2015-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading2"><h2 id="Sensory_roles_and_variation">Sensory roles and variation</h2></div>
<p>Beyond sensing gravity, the cap acts as a broader signalling hub. Asymmetric redistribution of the plant hormone <a href="Auxin" title="Auxin">auxin</a> in its statolith-bearing cells initiates curvature that restores the root to the gravity vector; related pathways also mediate water-seeking (<a href="Hydrotropism" title="Hydrotropism">hydrotropism</a>) and help position future <a href="Lateral_root" title="Lateral root">lateral roots</a>, shaping overall root-system architecture.<sup id="cite_ref-Kumpf_&_Nowack_2015_4-1" class="reference"><a href="#cite_note-Kumpf_&_Nowack_2015-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup>
</p><p>A true root cap is absent in some <a href="Parasitic_plant" title="Parasitic plant">parasitic plants</a><sup id="cite_ref-Jeffrey_2007_5-0" class="reference"><a href="#cite_note-Jeffrey_2007-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> and several <a href="Aquatic_plant" title="Aquatic plant">aquatic plants</a>, which instead form a thin, sac-like <i>root pocket</i> that performs a reduced protective role.<sup id="cite_ref-Gupta_2007_6-0" class="reference"><a href="#cite_note-Gupta_2007-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup>
</p>
<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>
<style data-mw-deduplicate="TemplateStyles:r1239543626">
/* start https://en.wikipedia.org/ */
.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}
/* end https://en.wikipedia.org/ */
</style><div class="reflist reflist-columns references-column-width" style="column-width: 30em;">
<ol class="references">
<li id="cite_note-Raven_&_Edwards_2001-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-Raven_&_Edwards_2001_1-0">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">
/* start https://en.wikipedia.org/ */
.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("./mw/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("./mw/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("./mw/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("./mw/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}
/* end https://en.wikipedia.org/ */
</style><cite id="CITEREFRavenEdwards2001" class="citation journal cs1">Raven, J.A.; Edwards, D. (2001). <a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fjexbot%2F52.suppl_1.381">"Roots: evolutionary origins and biogeochemical significance"</a>. <i>Journal of Experimental Botany</i>. <b>52</b>: <span class="nowrap">381–</span>401. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fjexbot%2F52.suppl_1.381">10.1093/jexbot/52.suppl_1.381</a></span>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/11326045">11326045</a>.</cite></span>
</li>
<li id="cite_note-Burgess_1985-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-Burgess_1985_2-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFBurgess1985" class="citation book cs1">Burgess, Jeremy (1985). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=r808AAAAIAAJ&dq=root+cap&pg=PA108"><i>Introduction to Plant Cell Development</i></a>. CUP Archive. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>9780521316118</bdi>.</cite></span>
</li>
<li id="cite_note-Kuya_&_Sato_2011-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-Kuya_&_Sato_2011_3-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFKuyaSato2011" class="citation journal cs1">Kuya, Noriyuki; Sato, Seiichi (2011). "The relationship between profiles of plagiogravitropism and morphometry of columella cells during the development of lateral roots of <i>Vigna angularis</i>". <i>Advances in Space Research</i>. <b>47</b> (3): <span class="nowrap">553–</span>562. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1016%2Fj.asr.2010.09.009">10.1016/j.asr.2010.09.009</a>.</cite></span>
</li>
<li id="cite_note-Kumpf_&_Nowack_2015-4"><span class="mw-cite-backlink">^ <a href="#cite_ref-Kumpf_&_Nowack_2015_4-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Kumpf_&_Nowack_2015_4-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"> <cite id="CITEREFKumpfNowack2015" class="citation journal cs1">Kumpf, Robert P.; Nowack, Moritz K. (2015). "The root cap: a short story of life and death". <i>Journal of Experimental Botany</i>. <b>66</b> (19): <span class="nowrap">5651–</span>5662. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1093%2Fjxb%2Ferv295">10.1093/jxb/erv295</a>. <a href="PMID_(identifier)" class="mw-redirect" title="PMID (identifier)">PMID</a> <a rel="nofollow" class="external text" href="https://pubmed.ncbi.nlm.nih.gov/26068468">26068468</a>.</cite></span>
</li>
<li id="cite_note-Jeffrey_2007-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-Jeffrey_2007_5-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFJeffrey2007" class="citation book cs1">Jeffrey, Edward Charles (2007). <i>The Anatomy of Woody Plants</i>. Pomeroy, Ohio: Carpenter Press. p. 138. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-4067-1634-4</bdi>.</cite></span>
</li>
<li id="cite_note-Gupta_2007-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-Gupta_2007_6-0">^</a></b></span> <span class="reference-text"><cite id="CITEREFGupta2007" class="citation book cs1">Gupta, P.K. (2007). <i>Genetics: Classical to Modern</i>. Rastogi Publications. pp. <span class="nowrap">2–</span>76. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-8-1713-3896-2</bdi>.</cite></span>
</li>
</ol></div></div><!--htdig_noindex--><div><div class="zim-footer">
This article is issued from <a class="external text" title="Last edited on 2025-06-25" href="https://en.wikipedia.org/wiki/?title=Root_cap&oldid=1297246319">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.
</div>
</div><!--/htdig_noindex--></div>
</div>
</main>
</div>
</div>
</div>
</body></html>