Name: how guard cells open plant stomata
Uploaded: 2026-08-26T08:19:56.906Z
Duration: 2 min 19 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.14

SC.912.L.14.7

Regulation of Transpiration by Stomata

Pflanzen ben&#xF6;tigen reichlich
Kohlendioxid
aus der Atmosph&#xE4;re, um
die Photosynthese auszuf&#xFC;hren.
Die Oberfl&#xE4;chen der Pflanzenbl&#xE4;tter
enthalten &#xD6;ffnungen,
die den Gasaustausch erleichtern.
Diese &#xD6;ffnungen werden
Stomata genannt.
Sonnenlicht veranlasst die
&#xD6;ffnungen der Stomata,
was Kohlendioxid erm&#xF6;glicht,
in das Blatt einzudringen, wenn es
f&#xFC;r die Photosynthese ben&#xF6;tigt wird.
Sauerstoff ist ein Nebenprodukt
der Photosynthese
und tritt aus in die
Atmosph&#xE4;re durch die Stomata.
Ein Paar von W&#xE4;chterzellen reguliert
jede Stomata&#xF6;ffnung.
Diese spezialisierten
Zellen schwellen an, wenn
sie Wasser von benachbarten
Zellen mittels Osmose aufnehmen,
womit eine &#xD6;ffnung erzeugt wird, die
den Gasaustausch erm&#xF6;glicht.
Wenn Wasser die W&#xE4;chterzellen
verl&#xE4;sst,
schrumpfen sie zusammen und
das Stoma schlie&#xDF;t sich.
Die Konzentration von Ionen
beeinflusst die Menge
von Wasser in den W&#xE4;chterzellen.
Sonnenlicht stimuliert die W&#xE4;chterzellen,
Kaliumionen aufzunehmen.
Der Anstieg der
Kaliumkonzentration
treibt Wasser in die Zellen,
dabei wird das Stoma ge&#xF6;ffnet.
Wenn Kalium die
W&#xE4;chterzellen verl&#xE4;sst,
folgt das Wasser mittels Osmose.
Die nun erschlafften
W&#xE4;chterzellen schlie&#xDF;en das Stoma.
W&#xE4;hrend das ge&#xF6;ffnete Stoma
den Gasaustausch erleichtert,
erm&#xF6;glichen sie auch, dass Wasser
aus den Bl&#xE4;ttern
durch Verdunstung austritt.
Der Verlust von Wasser durch
Verdunstung &#x2013; oder Transpiration - erm&#xF6;glicht
die Bewegung von Wasser &#xFC;ber gro&#xDF;e
Distanzen durch die Pflanze.
Transpiration ist
typischerweise am gr&#xF6;&#xDF;ten
an warmen und sonnigen Tagen.
Wenn eine Pflanze jedoch nicht
gen&#xFC;gend Wasser erhalten kann,
werden deren Stomata sich schnell
schlie&#xDF;en, um dem Welken vorzubeugen.
Interessanterweise &#xF6;ffnen und schlie&#xDF;en
Pflanzen die Stomata regelm&#xE4;&#xDF;ig,
wenn sie im Dunkeln gehalten werden,
in einem Zyklus von 24 Stunden,
aufgrund einer
internen Uhr.
Das &#xD6;ffnen und
Schlie&#xDF;en der Stomata
ist strikt geregelt,
was den Pflanzen erm&#xF6;glicht,
auf spezifische Umweltbedingungen
zu reagieren.
In ihrer Funktion als
Torw&#xE4;chter balancieren
Stomata wirksam
den Gasaustausch und die Transpiration.

Daszkowska-Golec, Agata und Iwona Szarejko. "Öffnen oder schließen Sie das Tor – Stomata-Wirkung unter der Kontrolle von Phytohormonen unter Trockenstressbedingungen." Frontiers in Plant Science 4 (2013). [<a href="https://doi.org/10.3389/fpls.2013.00138" target="_blank">Quelltext</a>]

Inoue, Shin-ichiro und Toshinori Kinoshita. "Blaulichtregulation der Stomataöffnung und der Plasmamembran H+-ATPase1[OPEN]." Pflanzenphysiologie 174, Nr. 2 (Juni 2017): 531–38. [<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5462062/" target="_blank">Source</a>].

regulation der transpiration durch die stomata

W&#xE4;hrend der Photosynthese nehmen Pflanzen das notwendige Kohlenstoffdioxid auf und geben den produzierten Sauerstoff in die Atmosph&#xE4;re ab. &#xD6;ffnungen in der Epidermis von Pflanzenbl&#xE4;ttern ist der Ort dieses Gasaustausches. Eine einzelne &#xD6;ffnung wird als Stoma (Spalt&#xF6;ffnung) bezeichnet &#x2013; abgeleitet vom griechischen Wort f&#xFC;r &#x22;Mund&#x22;. Stomata offen und schlie&#xDF;en sich als Reaktion auf eine Vielzahl an Umweltreizen.
 
 Jedes Stoma wird von zwei spezialisierten Schlie&#xDF;zellen flankiert, die eine &#xD6;ffnung erzeugen, wenn diese Zellen Wasser aufnehmen. Der Transport von Ionen reguliert die Wassermenge in den Schlie&#xDF;zellen. Wenn diese aktiviert werden transportieren Pumpen Wasserstoff-Ionen aus den Schlie&#xDF;zellen heraus. Diese Hyperpolarisation der Membran bewirkt dann die &#xD6;ffnung von spannungsgebundene Kaliumkan&#xE4;le und gel&#xF6;ste Stoffe, wie Kalium-Ionen und Saccharose k&#xF6;nnen in die Schlie&#xDF;zellen eintreten. Die erh&#xF6;hte Konzentration von der gel&#xF6;sten Stoffe f&#xFC;hrt zur Aufnahme von Wasser in die Schlie&#xDF;zellen, welches sich in den Vakuolen ansammelt. Als Ergebnis beugen sich die Schlie&#xDF;zellen und verformen sich zu einer Bohne, wodurch die Spalt&#xF6;ffnung entsteht. Wenn gel&#xF6;ste Stoffe die Schlie&#xDF;zellen verlassen, folgt das Wasser und die Schlie&#xDF;zellen schrumpfen wieder wodurch sich die Spalt&#xF6;ffnung schlie&#xDF;t.
 
 Eine Vielzahl von Umwelt- und internen Signalen l&#xF6;sen die &#xD6;ffnungen der Stomata aus. Beispielsweise aktiviert blaues Licht lichtempfindliche Rezeptoren auf der Zelloberfl&#xE4;che, die eine molekulare Kaskade initiieren, die zur &#xD6;ffnung der Stomata f&#xFC;hrt. Dar&#xFC;ber hinaus werden die Stomata ge&#xF6;ffnet, sobald die Konzentration des Kohlenstoffdioxids im Blattgewebe sinkt, so dass die Zellen auf diesen kritischen Reaktanten der Photosynthese Zugriff haben.
 
 Der Verlust von Wasserdampf ist entscheidend f&#xFC;r die Etablierung des Transpirationssogs: Wasser verdunstet auf der Oberfl&#xE4;che von Mesophyllzellen und entweicht durch ge&#xF6;ffnete Stomata in die Atmosph&#xE4;re. Der Wasserverlust erzeugt einen Transpirationssog, der zus&#xE4;tzliches Wasser aus dem Boden in die Wurzeln und in die Bl&#xE4;tter zieht.
 
 Wenn nicht gen&#xFC;gend Wasser zur Verf&#xFC;gung steht, wie unter D&#xFC;rrebedingungen, schlie&#xDF;en sich die Stomata. Das Hormon Abscisins&#xE4;ure (ABA) ist in diesem Prozess wichtig, da es an Rezeptoren in der Zellmembran der Schlie&#xDF;zellen bindet und somit die intrazellul&#xE4;re Konzentration von gel&#xF6;sten Stoffen erh&#xF6;ht. ABA spielt auch eine Rolle bei der circadianen Kontrolle der Spalt&#xF6;ffnung, wodurch Stomata bei Tageslicht ge&#xF6;ffnet und im Dunkeln geschlossen werden.

Regulation der Transpiration durch die Stomata

During photosynthesis, plants acquire the necessary carbon dioxide and release the produced oxygen back into the atmosphere. Openings in the epidermis of ...

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Education

Lehre

JoVE Core

Biology

Biologie

Plant Biology

Pflanzenbiologie

Plant Structure, Growth and Function

Pflanzenstruktur, Wachstum und Ernährung

KEY TERMS AND CONCEPTS

KERNBEGRIFFE UND KONZEPTE

how guard cells open plant stomata

How guard cells open and close plant stomata controls gas exchange in leaves. A stoma is a tiny opening in the leaf epidermis. The word comes from the Greek word for “mouth.” These openings let plants take in carbon dioxide for photosynthesis and release oxygen into the air.

Each stoma is surrounded by two guard cells. When these cells take up water, they create an opening. Ion transport controls how much water stays in the guard cells. A trigger causes pumps to move hydrogen ions out of the guard cell. This changes the membrane voltage and opens voltage-gated potassium channels. Potassium ions and sucrose then enter the guard cells. As solute levels rise, water moves in and collects in the vacuole. The guard cells swell, bend, and take on a kidney shape, which opens the stoma.

Stomata also close when solutes leave the guard cells. Water follows the solutes out, so the guard cells shrink and the opening closes. Blue light can start this process of opening. Light-sensitive receptors on the cell surface begin a molecular cascade. Low carbon dioxide inside the leaf can also trigger opening so cells can keep using this key photosynthesis reactant.

Water loss through open stomata helps create transpirational pull. Water evaporates from the surface of mesophyll cells and escapes into the atmosphere through the stomata. This pull draws more water from the soil, through the roots, and up into the leaves. When water is scarce, such as during drought, stomata close. The hormone abscisic acid, or ABA, helps drive this response by binding to receptors on guard cell membranes and increasing intracellular solute concentration. ABA also supports circadian control, so more stomata are open in daylight and closed in the dark.

How Guard Cells Open Plant Stomata

introduction to plant diversity

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xylem and transpiration-driven transport of resources

xylem-and-transpiration-driven-transport-of-resources

How Xylem Moves Water in Plants

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regulation of transpiration by stomata

How guard cells open and close plant stomata controls gas exchange in leaves. A stoma is a tiny opening in the leaf epidermis. The word comes from the Greek word for “mouth.” These openings let plants take in carbon dioxide for photosynthesis and release oxygen into the air. Each stoma is surrounded by two guard cells. When these cells take up water, they create an opening. Ion transport controls how much water stays in the guard cells. A trigger causes pumps to move hydrogen ions out of the...

adaptations that reduce water loss

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the roles of bacteria and fungi in plant nutrition

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the apoplast and symplast

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key terms and concepts

Explore how guard cells control stomata, gas exchange, and transpiration in leaves. Learn how light, CO2, and ABA affect opening and closing.

How Guard Cells Open Plant Stomata | JoVE K12

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Georgia Standards of Excellence

9-12

Botany

SBO1.

Transport

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How Guard Cells Open Plant Stomata

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