Name: plant features that limit water loss
Uploaded: 2026-08-26T08:20:34.350Z
Duration: 2 min 35 s
Channel: JoVE

K12 Standards

Virginia  Standards of Learning

HIgh School

Life Science

LS.7

LS.7.b

Adaptations that Reduce Water Loss

A &#xE1;gua &#xE9; cr&#xED;tica para as plantas fazerem fotoss&#xED;ntese, metabolizarem, e manterem sua estrutura m&#xF3;vel. Por isso, a perda excessiva de &#xE1;gua &#xE9; problem&#xE1;tica para plantas. Quais adapta&#xE7;&#xF5;es evolu&#xED;ram para permitir que as plantas durem e resistam &#xE0; perda de &#xE1;gua?A maioria das plantas t&#xEA;m um cut&#xED;cula cerosa que cobre a superf&#xED;cie da folha, impedindo a evapora&#xE7;&#xE3;o da &#xE1;gua. A composi&#xE7;&#xE3;o espec&#xED;fica da cut&#xED;cula influencia para que suas pequenas aberturas de &#xE1;gua na superf&#xED;cie, chamada estomas, facilitem a troca de g&#xE1;s e transpira&#xE7;&#xE3;o. Para minimizar a perda de &#xE1;gua, as plantas ajustam a densidade e a localiza&#xE7;&#xE3;o dos estomas nas folhas em desenvolvimento em resposta &#xE0; disponibilidade de &#xE1;gua e luz.Na maioria das &#xE1;rvores dec&#xED;duas, por exemplo, os estomas est&#xE3;o localizados nas partes inferiores das folhas. Al&#xE9;m disso, a densidade do estoma &#xE9; mais alta nas folhas pr&#xF3;ximas ao centro da &#xE1;rvore e mais baixos nas folhas perif&#xE9;ricas. A conserva&#xE7;&#xE3;o de &#xE1;gua &#xE9; especialmente cr&#xED;tica para as plantas que vivem no deserto.O arbusto do deserto encelia farinosa ret&#xE9;m &#xE1;gua em torno de suas folhas com min&#xFA;sculos pelos nas folhas. Estes pelos, chamados tricomas, desviam o sol e diminuem o efeito da secagem do vento. Outras plantas do deserto, como o Figo da &#xCD;ndia, armazenam &#xE1;gua dentro de suas hastes carnudas para se protegerem contra a seca.Al&#xE9;m disso, os cacos t&#xEA;m folhas modificadas, chamadas espinhos, que reduzem a evapora&#xE7;&#xE3;o e dissipam o calor. As plantas em ambientes &#xE1;ridos tamb&#xE9;m podem reduzem a evapora&#xE7;&#xE3;o absorvendo di&#xF3;xido de carbono apenas &#xE0; noite. Durante o dia, os estomas permanecem fechados.Este processo &#xE9; chamado metabolismo &#xE1;cido das crassul&#xE1;ceas, Ou CAM. A arquitetura espec&#xED;fica das folhas tamb&#xE9;m pode ajudar a reduzir a perda de &#xE1;gua. As folhas pequenas ou finas reduzem a evapora&#xE7;&#xE3;o.As gram&#xED;neas adquiriram estruturas de folhas enroladas ou dobradas que reduzem igualmente a &#xE1;rea de superf&#xED;cie e, portanto, a evapora&#xE7;&#xE3;o.

Buckley, Thomas N., Grace P. John, Christine Scoffoni e Lawren Sack. "Os locais de evaporação dentro das folhas." Fisiologia Vegetal 173, nº 3 (2017): 1763-1782. [<a href="https://www.ncbi.nlm.nih.gov/pubmed/28153921" target="_blank">Fonte</a>]

Borland, et al. "Agrossilvicultura resiliente ao clima: respostas fisiológicas às mudanças climáticas e engenharia do metabolismo do ácido crassuláceo (CAM) como estratégia de mitigação." Planta, Célula e Meio Ambiente 38, nº 9 (2015): 1833-1849. [<a href="https://www.ncbi.nlm.nih.gov/pubmed/25366937" target="_blank">Fonte</a>]

Yang X et al. Um roteiro para pesquisa sobre o metabolismo do ácido crassuláceo (CAM) para melhorar a produção sustentável de alimentos e bioenergia em um mundo mais quente e seco. Novo Fitol. Agosto de 2015; 207(3):491-504. [<a href="https://www.ncbi.nlm.nih.gov/pubmed/26153373" target="_blank">Fonte</a>]

Jalakas, Pirko, Ebe Merilo, Hannes Kollist e Mikael Brosché. "A regulação mediada por ABA da densidade estomática é independente de OST1." Plant Direct 2, nº 9 (1º de setembro de 2018). [<a href="https://doi.org/10.1002/pld3.82" target="_blank">Fonte</a>]

adaptações que reduzem a perda de Água

Embora a evapora&#xE7;&#xE3;o das folhas vegetais impulsione a transpira&#xE7;&#xE3;o, tamb&#xE9;m resulta em perda de &#xE1;gua. Como a &#xE1;gua &#xE9; fundamental para rea&#xE7;&#xF5;es fotossint&#xE9;ticas e outros processos celulares, press&#xF5;es evolutivas sobre plantas em diferentes ambientes t&#xEA;m impulsionado a aquisi&#xE7;&#xE3;o de adapta&#xE7;&#xF5;es que reduzem a perda de &#xE1;gua.
 
 Em plantas terrestres, a camada celular superior de uma folha de planta, chamada epiderme, est&#xE1; revestida com uma subst&#xE2;ncia cerada chamada cut&#xED;cula. Esta camada hidrof&#xF3;bica &#xE9; composta pelo pol&#xED;mero cutina e outras ceras derivadas de plantas que s&#xE3;o sintetizadas por c&#xE9;lulas epid&#xE9;rmicas. Essas subst&#xE2;ncias previnem a perda indesejada de &#xE1;gua e a entrada de solutos n&#xE3;o necess&#xE1;rios. A composi&#xE7;&#xE3;o espec&#xED;fica e a espessura da cut&#xED;cula variam de acordo com esp&#xE9;cies e ambientes vegetais. Outras adapta&#xE7;&#xF5;es de folhas tamb&#xE9;m podem minimizar a evapora&#xE7;&#xE3;o, principalmente pela redu&#xE7;&#xE3;o da &#xE1;rea da superf&#xED;cie. Por exemplo, algumas gram&#xED;neas t&#xEA;m uma estrutura dobrada que reduz a perda de &#xE1;gua. Alternativamente, outras esp&#xE9;cies de relva passam por um enrolamento da l&#xE2;mina para proteger contra a evapora&#xE7;&#xE3;o. Algumas plantas que habitam o deserto t&#xEA;m folhas revestidas por p&#xEA;los microsc&#xF3;picos que prendem vapor de &#xE1;gua, reduzindo assim a evapora&#xE7;&#xE3;o.
 
 A &#xE1;gua evapora principalmente atrav&#xE9;s de pequenos buracos em folhas de plantas chamadas estomas. Os estomas de algumas plantas est&#xE3;o localizados exclusivamente &#xE0; superf&#xED;cie da folha inferior, protegendo-as da evapora&#xE7;&#xE3;o excessiva associada ao calor. Outras plantas capturam vapor de &#xE1;gua perto de estomas que est&#xE3;o localizados em po&#xE7;os nas suas folhas, reduzindo a perda de &#xE1;gua por evapora&#xE7;&#xE3;o, uma vez que as c&#xE9;lulas-guarda que flanqueiam a abertura dos estomas podem sentir humidade relativa. Algumas plantas do deserto abrem os seus estomas apenas &#xE0; noite quando a evapora&#xE7;&#xE3;o &#xE9; menos prov&#xE1;vel de ocorrer. Essa estrat&#xE9;gia &#xE9; chamada de Metabolismo &#xC1;cido das Crassul&#xE1;ceas (CAM), e plantas que o usam capturam e fixam di&#xF3;xido de carbono &#xE0; noite, e executam rea&#xE7;&#xF5;es fotossint&#xE9;ticas dependentes da luz durante o dia. Alguns cientistas propuseram criar plantas por bioengenharia para desvincular a fixa&#xE7;&#xE3;o de carbono da fotoss&#xED;ntese, utilizando o CAM como um esfor&#xE7;o de mitiga&#xE7;&#xE3;o para a evapora&#xE7;&#xE3;o associado ao aquecimento das temperaturas globais.

Adaptações que Reduzem a Perda de Água

Though evaporation from plant leaves drives transpiration, it also results in loss of water. Because water is critical for photosynthetic reactions and ...

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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

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 thickness and makeup vary with plant species and growing conditions.

Some plants also reduce water loss by changing leaf shape. Certain grasses have folded leaves, and others roll their leaf blades to limit evaporation. Desert plants may have microscopic hairs on their leaves that trap water vapor and slow water loss.

Most water leaves a plant through stomata, which are tiny openings in the leaf. In some plants, stomata are found only on the lower leaf surface, where they are less exposed to heat. Other plants place stomata in pits, where trapped water vapor raises humidity around the guard cells and lowers evaporation.

A few desert plants use Crassulacean Acid Metabolism, or CAM. These plants open their stomata at night, when evaporation is lower, and capture carbon dioxide then. During the day, they carry out the light-dependent reactions of photosynthesis. Scientists have also suggested using CAM in bioengineering to help plants cope with warming global temperatures.

Plant Features That Limit Water Loss

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...

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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

Plant Growth and Support Tissues

Plant growth and support tissues help plants grow, protect themselves, and move materials through the body. Plant tissues are groups of similar cells that do related jobs. These tissues combine to form organs such as flowers, fruit, stems, and leaves. Two major kinds of plant tissue are meristematic tissue and permanent tissue. Meristematic tissue is the main growth tissue in plants. It can keep dividing and renewing itself, and every plant cell begins in a meristem. Meristematic tissue is...

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

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

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.

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 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

Soil Layers and How Soil Forms

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

Explore leaf cuticle, stomata, leaf shape, hairs, and CAM photosynthesis adaptations that help plants reduce water loss in dry environments.

Plant Features That Limit Water Loss | JoVE K12

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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.

Florida Department of Education

High School

SC.912.L.14

SC.912.L.14.7

Georgia Standards of Excellence

9-12

Botany

SBO1.

Transport

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LS.7.a

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Responses to Gravity and Touch

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Migration

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Communication

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The student will investigate and understand that adaptations support an organism's survival in an ecosystem. Key ideas include physical and behavioral characteristics enable organisms to survive within a specific ecosystem.

Plant Features That Limit Water Loss

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