Name: plant carbon fixation in hot climates
Uploaded: 2019-03-11T09:21:13.000Z
Duration: 1 min 27 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Environmental Science

Earth’s Systems

HS-ESS2-6

C4 Pathway and CAM

Algumas plantas como o milho adaptaram maneiras alternativas de fixar carbono de forma mais eficiente em ambientes quentes e secos. Em uma via C4, durante a primeira etapa de fixação de carbono, o dióxido de carbono, CO2, entra nas células do mesofilo e através da enzima PEP carboxilase, combina com o composto de três carbonos, PEP, para formar um composto de quatro carbonos, o oxaloacetato, que é então convertido em outro ácido orgânico. Nesse caso, o malato.O malato é transportado para o feixe reveste as células profundamente na folha, onde o oxigénio é limitado e quebrado, liberando CO2, que pode então prosseguir através do ciclo de Calvin e, em seguida, interagir com RuBisCO para eventualmente produzir açúcares. Outras plantas, como o abacaxi, usam o metabolismo ácido das crassuláceas ou caminho CAM para fixar carbono. As plantas CAM apenas abrem seus estômatos à noite para evitar a perda de água durante o dia.Semelhante ao caminho C4, o CO2 é primeiro fixado pela PEP carboxilase em oxaloacetato que é então convertido em malato. Em vez de transferir malato para outra parte da folha, As plantas CAM armazenam este composto em vacúolos de células mesófilas, e liberam durante o dia para que o ciclo de Calvin possa prosseguir juntamente com as reações de luz na fotossíntese.

<ol>
	<li>Edwards, E.J. Trajetórias evolutivas, acessibilidade e outras metáforas: o caso da fotossíntese C4 e CAM. Novo Fitologista. 223 (4), 1742-1755 (2019).</li>
</ol>

via c4 e cam

<h4>Visão Geral</h4>
 
 Algumas plantas, como a cana-de-açúcar e o milho, que crescem em condições quentes, usam um processo alternativo chamado via C4 para fixar carbono. O ciclo começa com CO2 da atmosfera a entrar em células do mesófilo onde é usado para produzir oxaloacetato—uma molécula de quatro carbonos—a partir de fosfoenolpiruvato (PEP). O oxaloacetato é então convertido em malato e transportado para células do feixe vascular, onde a concentração de oxigénio é baixa. Lá, o CO2 é libertado do malato e entra no Ciclo de Calvin onde é convertido em açúcares. A via CAM é realizada em plantas como cactos que também precisam conservar água durante o dia. As plantas CAM deixam o CO2 entrar nas folhas durante a noite e produzem malato que é armazenado em vacúolos até ao dia seguinte. O malato é então libertado dos vacúolos e processado no Ciclo de Calvin. A via C4 separa os diferentes processos localmente, enquanto que a via CAM os separa temporalmente.
 
 <h4>A Via C4</h4>
 
 Algumas plantas, como o milho e a cana-de-açúcar, desenvolveram formas alternativas de fixação de carbono que ajudam a evitar a perda de água em ambientes quentes e secos. Um desses métodos é a via C4. No primeiro passo, o CO2 entra nas células do mesófilo, e a enzima fosfoenolpiruvato (PEP) carboxilase adiciona-o ao composto PEP de 3 carbonos para formar o composto oxaloacetato de 4 carbonos. O oxaloacetato é então convertido em um ácido orgânico chamado malato.
 
 Posteriormente, o malato é transportado para células do feixe vascular nas profundezas da folha onde a concentração de oxigénio é baixa. O malato é quebrado, libertando uma molécula de CO2 que entra então no Ciclo de Calvin onde a enzima rubisco converte-a em açúcar. A via C4 oferece uma vantagem em condições quentes e áridas, pois as plantas fecham os seus estomas para conservar água. Como resultado, elas podem manter a concentração de oxigénio baixa e, portanto, favorecer a ligação de CO2 à rubisco em vez de O2. Quando a concentração de oxigénio é maior, a rubisco liga O2 em vez de CO2—um processo chamado de fotorrespiração—que pararia a fotossíntese e consumiria energia.
 
 <h4>A Via CAM</h4>
 
 Outras plantas, como os cactos e o ananás, usam a via do metabolismo ácido das crassuláceas (CAM) para fixar carbono. As plantas CAM abrem os seus estomas principalmente à noite para evitar a perda de água durante o dia quente. À noite, o CO2 entra nas células do mesófilo, onde se combina com PEP para formar oxaloacetato e eventualmente malato. O malato é então armazenado em vacúolos até ao dia seguinte, quando é libertado dos vacúolos e entra no Ciclo de Calvin. Os primeiros passos da fotossíntese prosseguem durante o dia, pois são dependentes da luz, enquanto que as reações independentes da luz do ciclo de de Calvin ocorrem durante a noite. Assim, as plantas CAM separam a fixação de CO2 e a síntese de açúcar usando diferentes horas do dia.

Via C4 e CAM

A maioria das plantas usa a via C3 para fixação de carbono. No entanto, algumas plantas, como cana-de-açúcar, milho e cactos que crescem em condições quentes, usam ...

Education

JoVE Core

Biology

Biologia

Cellular Processes

Processos Celulares

Photosynthesis

Fotossíntese

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

plant carbon fixation in hot climates

Plant carbon fixation in hot climates can follow the C4 pathway or the CAM pathway. These alternative pathways help some plants reduce energy loss from photorespiration. Photorespiration happens when oxygen levels are high and rubisco, the enzyme in the Calvin cycle, binds O2 instead of CO2. When that happens, photosynthesis slows and energy is used up.

The C4 pathway is used by plants such as corn and sugarcane. In mesophyll cells, CO2 first joins with PEP, or phosphoenolpyruvate, through the action of PEP carboxylase. This forms the 4-carbon compound oxaloacetate, which is then changed into organic acids, mostly malate.

Malate moves into the bundle sheath cells deep in the leaf, where oxygen levels are low. There, malate is broken down and releases CO2. That CO2 enters the Calvin cycle and is turned into sugar with the help of RuBisCo. In hot, dry conditions, this separation of carbon fixing and sugar production helps the plant close its stomata and save water while keeping oxygen low.

Other plants, such as cacti and pineapple, use the CAM pathway, or crassulacean acid metabolism. CAM plants open their stomata at night to limit water loss during the day. CO2 enters the mesophyll cells at night and combines with PEP to form oxaloacetate and then malate.

The malate is stored in vacuoles until the next day. During the day, it is released so the Calvin cycle can begin. In CAM plants, carbon fixation happens at night, while sugar synthesis follows during the day with energy from the light-dependent reactions. This time-based separation helps these plants survive hot, dry environments.

Plant Carbon Fixation in Hot Climates

what is photosynthesis?

Photosynthesis in Chloroplasts and Leaves

Photosynthesis happens in plants and in some bacteria. It is the process that captures carbon dioxide and solar energy to make glucose. Glucose stores chemical energy as carbohydrates. The overall biochemical equation is 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2. Photosynthesis also releases oxygen into the atmosphere and helps maintain Earth’s atmospheric oxygen content. Photosynthetic reactions take place in chloroplasts, which are specialized membrane-enclosed parts of the plant cell.

light as energy

How Plant Pigments Capture Light

Photosynthesis uses light energy from the sun, which is a form of electromagnetic radiation. The full range of possible wavelengths is called the electromagnetic spectrum. Light is made of photons, which are small packets of energy. Photons act like waves and are described by frequency, wavelength, and amplitude. Waves with higher frequencies carry more energy and have shorter wavelengths. Waves with lower frequencies carry less energy and have longer wavelengths. For most organisms,...

anatomy of chloroplasts

Chloroplasts and Photosynthesis in Plant Cells

Chloroplasts are the organelles where photosynthesis takes place in green algae and plants. They are also found in green stems and unripe fruit. In plants, mesophyll cells in the leaf contain the highest density of chloroplasts. Each chloroplast has a double membrane. The outer membrane faces the plant cell cytoplasm on one side and the chloroplast intermembrane space on the other. The inner membrane separates that narrow space from the stroma, which is the watery interior of the chloroplast.

photosystem ii

Photosystem II and Water Splitting

Photosystem II is a multi-protein complex that captures light energy and begins the flow of electrons in photosynthesis. It uses bound pigments to harvest photons and send that energy to its reaction center. From there, the energy continues through the electron transport chain and on to photosystem I. The pigments in photosystem II include chlorophyll a, chlorophyll b, and carotenoids. They are arranged in two parts of the photosystem: the antenna complex and the reaction center. The antenna...

photosystem i

Photosystem I and NADPH Formation

Photosystem I helps convert light energy into NADPH during photosynthesis. It works with photosystem II in the thylakoid membrane of the chloroplast, but it uses a different electron supplier and a different electron acceptor. Electrons excited in photosystem II move to photosystem I through an electron transport chain. That chain includes plastoquinone, the dual-protein cytochrome complex, and plastocyanin. As the electrons travel between the two photosystems, they lose energy and must be...

the calvin cycle

Carbon Fixation in Photosynthesis

Photosynthesis uses light energy to turn carbon dioxide into carbohydrates. It also releases oxygen as a by-product. These products help support most food webs and make aerobic life possible. Photosynthesis has two main stages, and they happen in different parts of the chloroplast. The light-dependent reactions take place in the thylakoid membranes. Chlorophyll absorbs light energy there and helps split water molecules. This releases O2 and makes ATP and NADPH. The light-independent reactions...

c4 pathway and cam

Plant carbon fixation in hot climates can follow the C4 pathway or the CAM pathway. These alternative pathways help some plants reduce energy loss from photorespiration. Photorespiration happens when oxygen levels are high and rubisco, the enzyme in the Calvin cycle, binds O2 instead of CO2. When that happens, photosynthesis slows and energy is used up. The C4 pathway is used by plants such as corn and sugarcane. In mesophyll cells, CO2 first joins with PEP, or phosphoenolpyruvate, through the...

key terms and concepts

Learn how C4 and CAM pathways help plants like corn, sugarcane, cacti, and pineapple reduce photorespiration and save water in hot climates.

Plant Carbon Fixation in Hot Climates | 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.

Virginia  Standards of Learning

HIgh School

Life Science

LS.4

LS.4.a

Next Generation Science Standards

from-molecules-to-organisms-structures-and-processes

From Molecules to Organisms: Structures and Processes

HS-LS1-5

Texas Essential Knowledge and Skills

BIO.11

BIO.11.A

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

ecosystems-interactions-energy-and-dynamics

Ecosystems: Interactions, Energy, and Dynamics

B-LS2-5.

new-york-state-science-learning-standards

New York State Science Learning Standards

matter-and-energy-in-organisms-and-ecosystems

Matter and Energy in Organisms and Ecosystems

HS-LS1-5.

Georgia Standards of Excellence

9-12

SB1.e

myJoVE Corporation

determining-spatial-orientation-rock-layers-with-brunton

Determining Spatial Orientation of Rock Layers with the Brunton Compass

Source: Laboratory of Alan Lester - University of Colorado Boulder
Most rock units exhibit some form of planar surfaces or linear features. Examples ...

using-topographic-maps-to-generate-topographic-profiles

Using Topographic Maps to Generate Topographic Profiles

Source: Laboratory of Alan Lester - University of Colorado Boulder
Topographic maps are &#34;plan-view&#34; representations of Earth&#39;s ...

exploring-effects-atmospheric-forcings-on-evaporation-experimental

Exploring the Effects of Atmospheric Forcings on Evaporation: Experimental Integration of the Atmospheric Boundary Layer and Shallow Subsurface

Evaporation is directly influenced by the interactions between the atmosphere, land surface and soil subsurface. This work aims to experimentally study ...

Earth’s systems, being dynamic and interacting, include feedback effects that can increase or decrease the original changes.

HS-ESS2-2

What is Weather?

Overview

Weather refers to the current state of atmospheric conditions at a specific time and place. Weather is temporary and is influenced by the ...

What is Climate?

Climate refers to the prevailing weather conditions in a specific area over an extended period. As the saying goes, &#8220;Climate is what you expect. ...

Global Climate Change

Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global ...

The geological record shows that changes to global and regional climate can be caused by interactions among changes in the sun’s energy output or Earth’s orbit, tectonic events, hydrosphere circulation, volcanic activity, glaciers, vegetation, and human activities. These changes can occur on a variety of time scales from sudden (e.g., volcanic ash clouds) to intermediate (ice ages) to very long-term tectonic cycles.

HS-ESS2-4

Making a Geologic Cross Section

Source: Laboratory of Alan Lester - University of Colorado Boulder
Geologic maps were first made and utilized in Europe, in the mid-to-late 18th century. ...

physical-properties-of-minerals-i-crystals-and-cleavage

Physical Properties Of Minerals I: Crystals and Cleavage

Source: Laboratory of Alan Lester - University of Colorado Boulder
The physical properties of minerals comprise various measurable and discernible ...

physical-properties-of-minerals-ii-polymineralic-analysis

Physical Properties Of Minerals II: Polymineralic Analysis

Source: Laboratory of Alan Lester - University of Colorado Boulder
The physical properties of minerals include various measurable and discernible ...

Igneous Volcanic Rock

Source: Laboratory of Alan Lester - University of Colorado Boulder
Igneous rocks are the products of cooling and crystallization of magma. Volcanic rocks ...

Igneous Intrusive Rock

Source: Laboratory of Alan Lester - University of Colorado Boulder
Igneous rocks are products of the cooling and crystallization of high temperature ...

The abundance of liquid water on Earth’s surface and its unique combination of physical and chemical properties are central to the planet’s dynamics. These properties include water’s exceptional capacity to absorb, store, and release large amounts of energy, transmit sunlight, expand upon freezing, dissolve and transport materials, and lower the viscosities and melting points of rocks.

HS-ESS2-5

The foundation for Earth’s global climate systems is the electromagnetic radiation from the sun, as well as its reflection, absorption, storage, and redistribution among the atmosphere, hydrosphere, and land systems, and this energy’s re-radiation into space.

What is Photosynthesis?

Photosynthesis is a multipart, biochemical process that occurs in plants as well as in some bacteria. It captures carbon dioxide and solar energy to ...

Light as Energy

The energy required to carry out photosynthesis is light&#8212; typically electromagnetic radiation from the sun. The range of all possible wavelengths is ...

Anatomy of Chloroplasts

Green algae and plants, including green stems and unripe fruit, harbor chloroplasts&mdash;the vital organelles where photosynthesis takes place. In ...

Photosystem II

The multi-protein complex photosystem II (PS II) harvests photons and transfers their energy through its bound pigments to its reaction center, and ...

Photosystem I

Although structurally similar to photosystem II (PSII), photosystem I (PSI) is has a different electron supplier and electron acceptor.
Both these ...

The Calvin Cycle

Overview

Oxygenic photosynthesis converts approximately 200 billion tons of carbon dioxide (CO2) annually to organic compounds and produces approximately ...

Most plants use the C3 pathway for carbon fixation. However, some plants, such as sugar cane, corn, and cacti that grow in hot conditions, use alternative ...

Measuring Tropospheric Ozone

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Ozone is a form of elemental oxygen (O3), a molecule of three oxygen atoms ...

determination-of-nox-in-automobile-exhaust-using-uv-vis-spectroscopy

Determination Of NOx in Automobile Exhaust Using UV-VIS Spectroscopy

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
In the troposphere, ozone is naturally formed when sunlight splits nitrogen ...

carbon-and-nitrogen-analysis-of-environmental-samples

Carbon and Nitrogen Analysis of Environmental Samples

Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University
Elemental Analysis is a method used to determine elemental composition of a ...

Gradual atmospheric changes were due to plants and other organisms that captured carbon dioxide and released oxygen.

What are Biogeochemical Cycles?

The most common elements in organic molecules, carbon, hydrogen, oxygen, nitrogen, sulfur, and phosphorus, are only available in the ecosystem in limited ...

Cyclical changes in the shape of Earth’s orbit around the sun, together with changes in the tilt of the planet’s axis of rotation, both occurring over hundreds of thousands of years, have altered the intensity and distribution of sunlight falling on Earth. These phenomena cause a cycle of ice ages and other gradual climate changes.

Plant Carbon Fixation in Hot Climates

Description

Transcript

Tags

More videos by Standards