Name: root and shoot growth: length vs. width
Uploaded: 2026-08-26T08:20:10.285Z
Duration: 3 min 48 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Life Science

SC.912.L.14

SC.912.L.14.7

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

Primary and Secondary Growth in Roots and Shoots

Conforme uma planta cresce, os brotos e ra&#xED;zes alongam-se atrav&#xE9;s do crescimento prim&#xE1;rio e, em plantas lenhosas, engrossam atrav&#xE9;s do crescimento secund&#xE1;rio. Em hastes, o crescimento prim&#xE1;rio come&#xE7;a quando c&#xE9;lulas indiferenciadas no meristema apical do caule se dividem. Algumas c&#xE9;lulas descendentes se diferenciam em meristemas prim&#xE1;rios o protoderme, meristema fundamental, e proc&#xE2;mbio.Em &#xFA;ltima an&#xE1;lise, estes meristemas prim&#xE1;rios geram os tecidos maduros da planta:d&#xE9;rmico, fundamental, e tecido vascular. Especificamente, a protoderme produz a epiderme, um tecido d&#xE9;rmico. O meristema fundamental forma os tecidos fundamentais, incluindo medula e c&#xF3;rtex.O proc&#xE2;mbio gera o tecido vascular:floema prim&#xE1;rio e xilema prim&#xE1;rio. Nas ra&#xED;zes, por outro lado, o crescimento prim&#xE1;rio ocorre em tr&#xEA;s zonas sobrepostas de c&#xE9;lulas chamadas de zonas de divis&#xE3;o, alongamento, e diferencia&#xE7;&#xE3;o. A zona de divis&#xE3;o celular cont&#xE9;m a meristema apical da raiz.Na zona de alongamento, novas c&#xE9;lulas se alongam e se estendem nas pontas da raiz. Na zona de diferencia&#xE7;&#xE3;o, as c&#xE9;lulas se diferenciam em tipos distintos. Os meristemas apicais da raiz e do broto produzem os mesmos meristemas prim&#xE1;rios, que geram os mesmos tipos de tecido.No entanto, alguns tecidos diferem entre ra&#xED;zes e brotos. Por exemplo, tecido fundamental de raiz consiste principalmente de c&#xF3;rtex e n&#xE3;o tem medula. A ramifica&#xE7;&#xE3;o tamb&#xE9;m faz parte do crescimento prim&#xE1;rio.Brotos laterais ou galhos crescem de meristemas de bot&#xF5;es axilares na superf&#xED;cie da planta. Sinais hormonais inibem bot&#xF5;es axilares localizados pr&#xF3;ximos aos meristemas apicais ativos;isso &#xE9; chamado de domin&#xE2;ncia apical. Danos ou remo&#xE7;&#xE3;o do meristema apical por exemplo, por um animal se alimentando perturbam a domin&#xE2;ncia apical.&#xC9; assim tamb&#xE9;m que a poda incentiva o crescimento. Ao contr&#xE1;rio de brotos laterais, ra&#xED;zes laterais originam-se no periciclo, localizado pr&#xF3;ximo ao centro da raiz, e rompem os tecidos externos &#xE0; medida que surgem. O crescimento secund&#xE1;rio &#xE9; semelhante em ra&#xED;zes e brotos.Durante o crescimento secund&#xE1;rio, o c&#xE2;mbio vascular e o c&#xE2;mbio da casca geram os tecidos maduros. O c&#xE2;mbio vascular cria um xilema secund&#xE1;rio ou lenha e um floema secund&#xE1;rio. O c&#xE2;mbio da casca origina-se do periciclo nas ra&#xED;zes e no c&#xF3;rtex em brotos e produz c&#xE9;lulas da casta e a feloderme.O crescimento prim&#xE1;rio e secund&#xE1;rio contribuem para a not&#xE1;vel adaptabilidade das plantas, permitindo-lhes prosperar em ambientes mut&#xE1;veis apesar de sua imobilidade.

Ichihashi, Yasunori e Hirokazu Tsukaya. 2015. "Comportamento dos meristemas foliares e sua modificação." Fronteiras em Ciência das Plantas 6 (janeiro). [<a href="https://doi.org/10.3389/fpls.2015.01060" target="_blank">Fonte</a>]

Pierre-Jerome, Edith, Colleen Drapek e Philip N. Benfey. 2018. "Regulação da Divisão e Diferenciação de Células-Tronco Vegetais." Revisão Anual de Biologia Celular e do Desenvolvimento 34 (1): 289–310. [<a href="https://doi.org/10.1146/annurev-cellbio-100617-062459" target="_blank">Fonte</a>]

crescimento primário e secundário em raízes e sistemas caulinares

As plantas vasculares, que representam mais de 90 % da vegeta&#xE7;&#xE3;o da Terra, todas passam por crescimento prim&#xE1;rio&#x2014;que alonga ra&#xED;zes e sistemas caulinares. Muitas plantas terrestres, especialmente as plantas lenhosas, tamb&#xE9;m passam por crescimento secund&#xE1;rio&#x2014;que aumenta a espessura de ra&#xED;zes e sistemas caulinares.
O crescimento prim&#xE1;rio e secund&#xE1;rio pode ocorrer simultaneamente em uma planta. Enquanto o crescimento prim&#xE1;rio ocorre em regi&#xF5;es mais novas da planta, o crescimento secund&#xE1;rio ocorre em regi&#xF5;es que conclu&#xED;ram o crescimento prim&#xE1;rio. H&#xE1; semelhan&#xE7;as e diferen&#xE7;as entre o crescimento da raiz e o crescimento do sistema caulinar.
Os meristemas apicais possibilitam o crescimento prim&#xE1;rio tanto das ra&#xED;zes quanto dos sistemas caulinares - com o crescimento prim&#xE1;rio do sistema caulinar come&#xE7;ando no meristema apical caulinar e o crescimento prim&#xE1;rio da raiz come&#xE7;ando no meristema apical da raiz.
As c&#xE9;lulas em divis&#xE3;o nos meristemas apicais da raiz e do sistema caulinar diferenciam-se nos mesmos meristemas prim&#xE1;rios&#x2014;a protoderme, o meristema fundamental e o proc&#xE2;mbio. Tanto nas ra&#xED;zes quanto nos sistemas caulinares, esses meristemas prim&#xE1;rios desenvolvem-se nos mesmos tipos de tecido; a protoderme, o meristema fundamental e o proc&#xE2;mbio, respectivamente, desenvolvem-se em tecidos d&#xE9;rmicos, tecidos fundamentais e tecidos vasculares.
No entanto, h&#xE1; diferen&#xE7;as entre os tecidos espec&#xED;ficos produzidos nas ra&#xED;zes e nos sistemas caulinares. Nas ra&#xED;zes, a epiderme cont&#xE9;m pelos radiculares, que representam a maior parte da &#xE1;rea superficial da raiz. Al&#xE9;m disso, ao contr&#xE1;rio do tecido fundamental do sistema caulinar das eudicotiled&#xF4;neas&#x2014;as plantas com flores mais comuns&#x2014;o tecido fundamental da raiz n&#xE3;o &#xE9; dividido em medula e c&#xF3;rtex. Al&#xE9;m disso, o meristema apical caulinar cont&#xE9;m prim&#xF3;rdios foliares, que formam folhas.
Em compara&#xE7;&#xE3;o com o crescimento prim&#xE1;rio, o crescimento secund&#xE1;rio &#xE9; mais semelhante entre ra&#xED;zes e sistemas caulinares. O crescimento secund&#xE1;rio &#xE9; possibilitado por dois tipos de meristemas laterais, que se estendem ao longo das ra&#xED;zes e dos sistemas caulinares.
O c&#xE2;mbio vascular, localizado entre o xilema prim&#xE1;rio e o floema prim&#xE1;rio, produz anualmente uma camada de xilema secund&#xE1;rio (madeira) e de floema secund&#xE1;rio nas ra&#xED;zes e nos sistemas caulinares.
O felog&#xEA;nio, um componente da casca, localiza-se externamente aos tecidos vasculares. Tanto nas ra&#xED;zes quanto nos sistemas caulinares, ele produz s&#xFA;ber e feloderme para formar a periderme&#x2014;que substitui a epiderme.

Crescimento primário e secundário em raízes e sistemas caulinares

Vascular plants, which account for over 90% of the Earth&#x2019;s vegetation, all undergo primary growth&#x2014;which lengthens roots and shoots. Many land ...

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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

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 dividing cells. Shoot primary growth begins in the shoot apical meristem, while root primary growth begins in the root apical meristem.

Cells from these apical meristems become three primary meristems: the protoderm, ground meristem, and procambium. These meristems form the main tissue systems in both roots and shoots. The protoderm becomes dermal tissue, the ground meristem becomes ground tissue, and the procambium becomes vascular tissue.

Roots and shoots share the same basic plan, but they also differ in important ways. In roots, the epidermis has root hairs, which make up most of the root’s surface area. Root ground tissue is not divided into pith and cortex, unlike the shoot ground tissue of eudicots, which are the most common flowering plants. The shoot apical meristem also contains leaf primordia, which are young leaf structures that develop into leaves.

Secondary growth is more similar in roots and shoots than primary growth is. It depends on lateral meristems, which extend along the lengths of roots and shoots. The vascular cambium lies between the primary xylem and primary phloem and produces a yearly layer of secondary xylem, or wood, and secondary phloem.

The cork cambium is another lateral meristem and is part of bark. It sits outside the vascular tissues. In both roots and shoots, it makes cork and phelloderm. Together, these tissues form the periderm, which replaces the epidermis.

Root and Shoot Growth: Length vs. Width

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

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

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

Plant flowering and organ identity shape a plant’s form and structure. These changes depend on growth and cell differentiation, which work together during plant morphogenesis. Precursor cells become specialized cell types, and those cells are organized into tissues and organ systems that support the whole plant. Plant growth and cell differentiation are controlled by hormones. Plant hormones regulate gene expression, often in response to environmental stimuli. Temperature and day length are...

light acquisition

How Plants Maximize Sunlight Capture

Plants need light energy to make glucose, so leaf shape and plant structure help determine how well they capture sunlight. Many modern plants have evolved leaves that are specialized for light capture. Leaf size can vary from just a few millimeters wide to tens of meters wide, depending on the environment. Competition for sunlight has pushed evolution toward larger leaves and taller plants. These changes help plants avoid being shaded by nearby competitors. They also depend on root systems...

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

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

Learn how primary growth lengthens roots and shoots, while secondary growth thickens them through apical and lateral meristems in vascular plants.

Root and Shoot Growth: Length vs. Width | 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.

Georgia Standards of Excellence

9-12

Botany

SBO1.

Growth

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SC.912.L.14.4

A. Cells have characteristic structures and functions that make them distinctive.

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C. Life can be organized in a functional and structural hierarchy ranging from cells to the biosphere.

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Root and Shoot Growth: Length vs. Width

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