Name: how xylem moves water in plants
Uploaded: 2026-08-26T08:20:58.626Z
Duration: 2 min 21 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.14

SC.912.L.14.7

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

Xylem and Transpiration-driven Transport of Resources

As plantas adquirem &#xE1;gua e nutrientes da terra, mas requerem estas subst&#xE2;ncias mesmo em tecidos distantes. Como as plantas transportam estas subst&#xE2;ncias contra a for&#xE7;a da gravidade? &#xC1;gua e minerais dissolvidos entram na planta atrav&#xE9;s da raiz perme&#xE1;vel de c&#xE9;lulas ciliadas na epiderme e viajam para o xilema, onde o fluido &#xE9; chamado de seiva do xilema.A seiva do xilema &#xE9; distribu&#xED;da a partir das ra&#xED;zes para o resto da planta atrav&#xE9;s de um fluxo em massa, uma press&#xE3;o orientada pelo movimento do l&#xED;quido em longas dist&#xE2;ncias, atrav&#xE9;s de c&#xE9;lulas transportadoras especializados no xilema. As traque&#xED;des e elementos de vasos funcionam como um sistema de tubos flex&#xED;veis. Suas c&#xE9;lulas carecem de citoplasma e organelos e t&#xEA;m paredes celulares imperme&#xE1;veis, lignificadas, o que impede que a seiva do xilema vaze.O mecanismo prim&#xE1;rio que puxa a seiva do xilema atrav&#xE9;s da planta &#xE9; a transpira&#xE7;&#xE3;o das folhas. O espa&#xE7;o a&#xE9;reo entre as c&#xE9;lulas mes&#xF3;filas nas folhas fica saturado com vapor de &#xE1;gua durante o processo de fotoss&#xED;ntese e respira&#xE7;&#xE3;o celular. O ar fora da planta &#xE9; mais seco do que o ar dentro das folhas.Quando os estomas s&#xE3;o abertos, o vapor de &#xE1;gua se difunde ao longo de seu gradiente de concentra&#xE7;&#xE3;o, viajando em bolsas de ar h&#xFA;midas dentro da folha para a atmosfera fora da planta. Uma pel&#xED;cula de &#xE1;gua l&#xED;quida adere &#xE0; parede da c&#xE9;lula de cada c&#xE9;lula mes&#xF3;fila, facilitando a troca gasosa durante a fotoss&#xED;ntese e a respira&#xE7;&#xE3;o celular. Quando sai vapor de &#xE1;gua atrav&#xE9;s dos estomas, algo da &#xE1;gua l&#xED;quida evapora, gerando tens&#xE3;o que puxa a &#xE1;gua das veias da folha para as c&#xE9;lulas mes&#xF3;filas para reabastecer o tecido.A press&#xE3;o negativa nas veias foliares ent&#xE3;o puxa a seiva do xilema para longe das ra&#xED;zes, subindo pelo caule, e para as folhas, transportando &#xE1;gua e minerais para toda a planta.

Hae Koo Kim, Parque Joonghyuk, Ildoo Hwang. Investigando o transporte de água através da rede de xilemas em plantas vasculares. Jornal de Botânica Experimental. Volume 65, Edição 7. [<a href="https://doi.org/10.1093/jxb/eru075" target="_blank">Fonte</a>]

xilema e transporte de recursos por transpiração

O xilema das plantas vasculares distribui &#xE1;gua e minerais dissolvidos que s&#xE3;o captados pelas ra&#xED;zes para o resto da planta. As c&#xE9;lulas que transportam seiva de xilema est&#xE3;o mortas ap&#xF3;s a maturidade, e o movimento da seiva de xilema &#xE9; um processo passivo.
 
 Traque&#xED;deos e elementos de vaso transportam seiva de xilema
 
 Elementos traque&#xED;deos s&#xE3;o as c&#xE9;lulas de transporte do xilema. Eles n&#xE3;o t&#xEA;m citoplasma e organelos quando est&#xE3;o maduros e s&#xE3;o considerados parte do apoplasto da planta porque se ligam diretamente ao espa&#xE7;o extracelular. Existem dois tipos de elementos traque&#xED;deos: traque&#xED;deos e elementos de vaso.
 
 Traque&#xED;deos s&#xE3;o c&#xE9;lulas alongadas com paredes lignificadas que cont&#xEA;m pequenas lacunas chamadas po&#xE7;os, que conduzem a seiva de xilema de uma c&#xE9;lula para outra em locais onde as suas paredes se sobrep&#xF5;em. Plantas vasculares sem sementes e a maioria das gimnosp&#xE9;rmicas, ou plantas con&#xED;feras, t&#xEA;m apenas traque&#xED;deos, que se acredita terem evolu&#xED;do antes dos elementos do vaso.
 
 Os elementos de vaso s&#xE3;o c&#xE9;lulas lignificadas mais largas que se acumulam verticalmente para formar vasos. Eles est&#xE3;o ligados por placas de perfura&#xE7;&#xE3;o, estruturas da extremidade celular especializadas que t&#xEA;m espa&#xE7;os atrav&#xE9;s dos quais a seiva de xilema pode fluir. O di&#xE2;metro maior e a estrutura mais eficiente das placas de perfura&#xE7;&#xE3;o significa que os vasos compostos por elementos de vaso podem mover um volume muito maior de seiva. A maioria das angios&#xE9;rmicas, ou plantas com flor, t&#xEA;m traque&#xED;deos e elementos de vaso.
 
 O transporte ativo de minerais cria um gradiente de press&#xE3;o da &#xE1;gua das ra&#xED;zes &#xE0;s folhas
 
 Enquanto que a &#xE1;gua entra passivamente em uma planta atrav&#xE9;s de c&#xE9;lulas radiculares perme&#xE1;veis, o transporte ativo &#xE9; necess&#xE1;rio para mover minerais para o xilema. A alta concentra&#xE7;&#xE3;o resultante de solutos nas ra&#xED;zes cria um gradiente no potencial de press&#xE3;o da &#xE1;gua dentro do xilema, com maior press&#xE3;o nas ra&#xED;zes e menor press&#xE3;o em outros locais da planta, onde os solutos est&#xE3;o menos concentrados. A &#xE1;gua ir&#xE1; mover-se em dire&#xE7;&#xE3;o aos locais de menor press&#xE3;o; no entanto, este gradiente &#xE9; apenas um pequeno contributo para o transporte global de seiva atrav&#xE9;s do xilema.
 
 For&#xE7;as f&#xED;sicas em mol&#xE9;culas de &#xE1;gua mant&#xEA;m fluido dentro do xilema
 
 O transporte de seiva de xilema atrav&#xE9;s de uma planta &#xE9; possibilitada em parte por algumas das propriedades f&#xED;sicas da pr&#xF3;pria &#xE1;gua. A hip&#xF3;tese de coes&#xE3;o-tens&#xE3;o para o transporte de seiva atrav&#xE9;s do xilema foi proposta pela primeira vez na d&#xE9;cada de 1890. A coes&#xE3;o entre mol&#xE9;culas de &#xE1;gua &#xE9; relativamente forte porque todos os tr&#xEA;s &#xE1;tomos de uma mol&#xE9;cula de &#xE1;gua podem participar da liga&#xE7;&#xE3;o de hidrog&#xE9;nio com outras mol&#xE9;culas de &#xE1;gua. Isso significa que a atra&#xE7;&#xE3;o transpiracional nas folhas pode afetar mol&#xE9;culas de &#xE1;gua em todo o xilema, como elos em uma cadeia, at&#xE9; &#xE0;s ra&#xED;zes.
 
 Outra for&#xE7;a, a ades&#xE3;o, permite que mol&#xE9;culas de &#xE1;gua se agarrem a superf&#xED;cies dentro da planta, como as paredes celulares das c&#xE9;lulas de mes&#xF3;filo na folha, onde a tens&#xE3;o superficial da &#xE1;gua &#xE9; essencial para tirar a seiva dos vasos de folhas quando o vapor de &#xE1;gua est&#xE1; a transpirar das folhas. A ades&#xE3;o de mol&#xE9;culas de &#xE1;gua &#xE0;s paredes dos vasos de xilema impede que a seiva escoe para baixo e para fora da planta atrav&#xE9;s das ra&#xED;zes quando os estomas se fecham e a tens&#xE3;o produzida pela transpira&#xE7;&#xE3;o cessa.

Xilema e Transporte de Recursos por Transpiração

The xylem of vascular plants distributes water and dissolved minerals that are taken up by the roots to the rest of the plant. The cells that transport ...

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Education

JoVE Core

Biology

Biologia

Plant Biology

Biologia Vegetal

Plant Structure, Growth and Function

Estrutura, Crescimento e Nutrição das Plantas

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

how xylem moves water in plants

Xylem moves water and dissolved minerals from the roots to the rest of the plant. The cells that carry xylem sap are dead when mature, so the flow is passive. Xylem transport depends on special tracheary elements, which connect directly with the extracellular space in the apoplast.

There are two main tracheary elements: tracheids and vessel elements. Tracheids are long cells with lignified walls and small pits. These pits let xylem sap move from one cell to the next where the walls overlap. Seedless vascular plants and most gymnosperms have only tracheids, which are thought to have evolved first.

Vessel elements are wider lignified cells that stack to form vessels. Their ends have perforation plates, which contain openings for sap flow. Because of their larger diameter and efficient perforation plates, vessels can move a much larger volume of sap. Most angiosperms have both tracheids and vessel elements.

Water enters the plant passively through permeable root cells, but minerals must be moved into the xylem by active transport. This builds a high solute concentration in the roots. That difference creates a water pressure gradient, with higher pressure in the roots and lower pressure elsewhere in the plant. Water moves toward the lower pressure areas, but this is only a minor part of xylem transport.

Water also moves because of its physical properties. The cohesion-tension hypothesis explains how transpiration in the leaves can pull water through the xylem. Cohesion between water molecules is strong because hydrogen bonding links them together. Adhesion helps water stick to cell walls in the leaf and along the xylem, which supports the pull of sap upward and helps prevent sap from leaking downward when stomata close.

How Xylem Moves Water in Plants

introduction to plant diversity

Plant Adaptations for Life on Land

Plant adaptations for life on land explain how Kingdom Plantae moved from water to land about 410 million years ago. This shift happened when green algae began colonizing a new environment that had not been widely occupied. Land offered more light and carbon dioxide for growth, but it also created major challenges for early plants. One key adaptation was the cuticle, a waxy outer layer that helps prevent water loss. It traps moisture inside the plant. But it also limited direct gas exchange...

non-vascular seedless plants

Nonvascular Plants and Their Life Cycle

Nonvascular plants include some of the earliest plants on Earth. Today, this group includes liverworts, mosses, and hornworts. These plants are also called bryophytes. They have no true roots, leaves, or stems because they lack extensive vascular tissue. Bryophytes reproduce with spores instead of seeds. Their life cycle is dominated by the haploid gametophyte stage, which produces eggs and sperm. The sporophyte stage makes haploid spores that can grow by mitosis into new gametophytes. In many...

seedless vascular plants

Fern Life Cycles and Vascular Tissue

Seedless vascular plants include ferns, horsetails, whisk ferns, and lycophytes. Ferns are the most common example. Whisk ferns and their relatives, along with horsetails, are monilophytes. Lycophytes include club mosses, spikemosses, and quillworts, and none of these are true mosses. Seedless vascular plants differ from nonvascular plants because they have vascular tissue. This tissue includes xylem and phloem, which move water and nutrients through the plant. Most seedless vascular plants...

introduction to seed plants

Seed Plants: Cones, Flowers, and Fruits

Seed plants are land plants that make seeds, use pollen, and have reduced gametophytes. This group includes gymnosperms and angiosperms. Gymnosperms include cycads, Ginkgo biloba, gnetophytes, and conifers. Gymnosperms usually form cones. Pollen cones contain the male gametophytes. Ovulate cones contain the female gametophytes and produce exposed seeds after fertilization. Angiosperms are the most diverse and widespread land plants. They form flowers and fruit, and both structures support...

basic plant anatomy: roots, stems, and leaves

basic-plant-anatomy-roots-stems-and-leaves

Plant Organs and Their Specialized Roles

Plants are built from roots, stems, and leaves, but each organ can change to fit a plant’s environment. These structures may look very different from one species to another. They still carry out the main jobs needed for growth and survival. Roots are usually underground, but that is not always true. Aerial roots grow aboveground. Epiphytic plants, such as orchids, can live without ever touching soil. In strangler figs and banyans, aerial roots begin aboveground, grow downward, and later reach...

plant cells and tissues

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meristems and plant growth

Plant Growth from Root and Shoot Tips

Plants grow throughout their lives, and that pattern is called indeterminate growth. This trait sets plants apart from most animals. Some plant parts stop growing, such as leaves and flowers, but roots and stems can keep growing for a long time. Meristems make this ongoing growth possible. A meristem is a plant tissue that contains undifferentiated cells called meristematic cells. When these cells divide, some daughter cells stay in the meristem. That keeps a supply of cells that can keep...

primary and secondary growth in roots and shoots

primary-and-secondary-growth-in-roots-and-shoots

Root and Shoot Growth: Length vs. Width

Root and shoot growth in vascular plants happens in two main ways: primary growth and secondary growth. Primary growth makes roots and shoots longer. Secondary growth makes them thicker. Many woody plants show both kinds of growth, and the two can happen at the same time. Primary growth happens in newer parts of the plant. Secondary growth happens in regions that have already finished primary growth. In roots and shoots, the process starts in apical meristems, which are areas of actively...

morphogenesis

Plant Flowering and Organ Identity

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light acquisition

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water and mineral acquisition

How Roots Absorb Water and Minerals

Roots absorb water and minerals from the soil using specialized tissues. Their branching patterns help them reach more soil, and root hairs on the outer cells increase surface area for contact with the ground. Water enters roots passively because the water concentration in the soil is higher than in root tissue. Minerals move in a different way. They are taken up actively by root cells, which requires energy and transport proteins. Soil particles carry a negative charge, so positive ions...

short-distance transport of resources

Plant Cell Membranes and Water Balance

Plant cell membranes control how water, ions, and other solutes move over short distances. This transport can happen across just 2 to 3 cells, and it begins at the plasma membrane. Small uncharged molecules, such as oxygen, carbon dioxide, and water, can diffuse through the membrane on their own. Ions and larger molecules need transport proteins because of their charge or size. Membrane transport also happens inside plant cells. The central vacuole stores resources and helps manage the cell’s...

xylem and transpiration-driven transport of resources

Xylem moves water and dissolved minerals from the roots to the rest of the plant. The cells that carry xylem sap are dead when mature, so the flow is passive. Xylem transport depends on special tracheary elements, which connect directly with the extracellular space in the apoplast. There are two main tracheary elements: tracheids and vessel elements. Tracheids are long cells with lignified walls and small pits. These pits let xylem sap move from one cell to the next where the walls overlap.

regulation of transpiration by stomata

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...

adaptations that reduce water loss

Plant Features That Limit Water Loss

Plant features that limit water loss help plants survive in dry or hot environments. Water is needed for photosynthesis and other cell processes, so plants have evolved several ways to slow evaporation from their leaves. One major barrier is the cuticle, a waxy layer on the leaf epidermis. The epidermis is the outer cell layer, and it makes cutin and other plant waxes that form this hydrophobic coating. The cuticle helps stop water from escaping and also keeps out unwanted solutes. Its...

phloem and sugar transport

How Phloem Moves Sugars in Plants

Phloem moves sugars and other materials through plants. In angiosperms, sugar production is mostly limited to photosynthetic cells in the leaves. These leaves act as sugar sources because they make more sugar than they use. Roots, shoots, flowers, and fruits are usually sugar sinks because they need more sugar than they can make. This movement is called translocation. It carries sugar, hormones, amino acids, and some signaling molecules from source tissues to sink tissues. The transport...

the soil ecosystem

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Soil supplies plants with water and inorganic minerals. It is the natural medium for land plants, and its quality depends on both chemical makeup and living organisms in the soil. Healthy soil contains enough air, water, minerals, and organic matter to support plant growth. Soil is made of three major components. Inorganic mineral matter makes up about 40 to 45 percent of soil volume. Organic matter, also called humus, makes up about 5 percent. Water and air fill about 50 percent of the volume.

key elements for plant nutrition

Plant Nutrients: Macro and Micro Needs

Plants need both organic and inorganic nutrients to survive, grow, reproduce, and keep normal cell function. Researchers use hydroponics to study these essential nutrients. In hydroponic culture, plants grow without soil in water-based nutrient solutions. At least 17 nutrients are known to be essential for plants. Plants get these elements from the atmosphere, the soil around their roots, and water. Nine of them are macronutrients, which plants need in larger amounts. These macronutrients are...

the roles of bacteria and fungi in plant nutrition

the-roles-of-bacteria-and-fungi-in-plant-nutrition

How Soil Microbes Help Plants Get Nutrients

Soil microbes help plants get nutrients, water, and protection. Plants can make their own food by photosynthesis, but they still depend on organisms in the soil to get the nutrients they need to work properly. Bacteria and fungi form symbiotic relationships with plants, which helps both partners survive in many environments. The bacteria living in and around plant roots are called the rhizosphere. This community is very diverse. Some bacteria can cause disease, but most help plant health. In...

epiphytes, parasites, and carnivores

Plant Nutritional Adaptations in Nature

Plant nutritional adaptations help some species survive by using fungi, bacteria, or other plants and animals. Many plants also rely on mutualistic partners in the soil. Root-colonizing fungi, such as mycorrhizae, increase root surface area and improve nutrient absorption. Nitrogen-fixing bacteria, such as rhizobia, convert atmospheric nitrogen (N2) into ammonia (NH3), which plants can use to build essential molecules like chlorophyll. These relationships benefit both sides. The plant gets...

the apoplast and symplast

Plant Water Transport Pathways

Plant water transport pathways help roots absorb water and dissolved minerals from the soil. These pathways move materials through plant tissues that support growth and nutrient uptake. The main tissue regions involved are the apoplast and the symplast. The apoplast includes everything outside the plasma membrane of living cells. It contains cell walls, extracellular spaces, xylem, phloem, and tracheids. The symplast is the cytosol of all living plant cells, along with the plasmodesmata that...

key terms and concepts

Learn how xylem transports water and minerals in plants, from tracheids and vessel elements to transpiration pull, cohesion, and adhesion.

How Xylem Moves Water in Plants | JoVE K12

JoVE Core series brings biology to life through over 300 concise and easy-to-understand animated video lessons that explain key concepts in biology, plus more than 150 scientist-in-action videos that show actual research experiments conducted in today’s laboratories.

biology

A coleção JoVE Core dá vida à biologia através de mais de 300 vídeos de animação concisos e fáceis de entender que explicam conceitos-chave de biologia, além de mais de 150 vídeos de Cientistas em ação que mostram experimentos reais em pesquisa realizados nos laboratórios atualmente.

Texas Essential Knowledge and Skills

BIO.12

BIO.12.B

new-york-state-science-learning-standards

New York State Science Learning Standards

Structure and Function

HS-LS1-2.

Georgia Standards of Excellence

9-12

Botany

SBO1.

Transport

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How Xylem Moves Water in Plants

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