81. IdahoPTV's Dialogue For Kids--Desert Habitat Nocturnal Unlike most plants that carry out photosynthesis, plants These kinds of plants will carry out photosynthesis only during the moist period. http://www.idahoptv.org/dialogue4kids/season3/desert/plants.html

Desert Facts Desert Plants Desert Misfits Desert Animals ... Dialogue For Kids Home Tricks of the Trade....How Desert Plants Survive How do desert plants save water? Desert plants work hard to make use of what's available. They use the sun's energy to convert carbon dioxide to (CO2) and water (H2O) into sugar, a process called photosynthesis. During this process, small pores (stomata) on a plant's leaves and stems open to absorb CO2 from the air and in return release oxygen (O2). Each time a plant opens its pores, some H2O is lost. This is called transpiration. Replacing this lost H2O is not easy with so little annual moisture; and if the H2O can not be replaced, the desert plants will die. A unique fact of desert plants is that they have acquired special adaptations that help them in reducing H2O loss. Smaller, fewer, and deeper pores - Many desert plants have very small, fewer, and deeper pores. With such pores, hot and dry winds are inhibited from blowing directly across the pores and reducing H2O loss. Waxy cover - Plants do not only lose H2O through their pores, they also lose it through the cell walls on their leaves. The leaves and stems of many desert plants have a thick covering that is coated with a waxy substance, allowing them to still open and absorb CO2.

82. PASCO Biology Experiment - October 2003 Through photosynthesis, plants convert sunlight energy into organic molecules, plants release oxygen into the air as a byproduct of photosynthesis. http://www.pasco.com/experiments/biology/october_2003/home.html

home resources experiments biology ... print page Online Biology Experiments October, 2003, Biology Experiment: Photosynthesis and Oxygen Purpose Background Information Experimental Procedure Data Analysis ... Conclusions and Extensions PASPORT Oxygen Gas Sensor (PS-2126) Purpose: Students will assess how changes in the amount of light available to plants affects photosynthesis by measuring the by-product of photosynthesis, oxygen. *Note: This experiment requires DataStudio version 1.8.5, available as a free download Background Information: Plants are the mediators of energy on this planet for all other living things. Through photosynthesis, plants convert sunlight energy into organic molecules, forming the basis of food for all organisms. In a series of reactions, light energy, carbon dioxide and water are combined to create food for plants. Photosynthesis consists of two reactions, the light-dependent and light-independent reaction. The light-dependent reaction of photosynthesis involves using light energy to remove hydrogen atoms from water molecules. The light-independent reaction in photosynthesis involves changing carbon dioxide and hydrogen into organic molecules. While no light is necessary for the second part of the process to occur, light is required to initiate the photosynthetic process. If the reactants of photosynthesis are water, light and carbon dioxide, the products are carbohydrates (stored plant energy) and oxygen gas. Plants release oxygen into the air as a byproduct of photosynthesis.

83. Ocean Colour: Light And Photosynthesis Nearly all life on Earth depends on photosynthesis. If plants stopped To capture light for photosynthesis, plants use special chemicals known as http://www.noc.soton.ac.uk/JRD/SCHOOL/mt/mt001b_1.html

This issue Next issue Previous issues About us Calendar Teachers Search LINKS Light and photosynthesis Photosynthesis and respiration: A simple carbon cycle Harvesting light Forests are sometimes called the Earth's lungs because they produce much of the oxygen we breathe. The ocean should rightly share this title. Photosynthesis in the ocean. From left to right: Seagrass bed, kelp forest, pillar coral with photosynthetic algae, and diatoms (a type of phytoplankton) under the microscope. Oceans and forests: Earth's lungs All plants and some bacteria trap energy from sunlight and use it to build sugars, which they need to live and grow. This process is called photosynthesis Nearly all life on Earth depends on photosynthesis. If plants stopped photosynthesising, animals would have no food, and the world would run out of oxygen in less than 2000 years. Plants on land produce about half the world's oxygen. The other half is produced by plants in the ocean - mostly by the microscopic plants known as phytoplankton Photosynthesis and respiration: A simple carbon cycle The carbon cycle.

84. Photosynthesis --  Encyclopædia Britannica photosynthesis the process by which green plants and certain other organisms During photosynthesis in green plants, light energy is captured and used to http://www.britannica.com/eb/article-9108553

Home Browse Newsletters Store ... Subscribe Already a member? Log in Content Related to this Topic This Article's Table of Contents Expand all Collapse all Introduction General characteristics Development of the idea Overall reaction of photosynthesis Basic products of photosynthesis Evolution of the process ... Structural features Chemical composition of lamellae Lipids Proteins Quinones The process of photosynthesis: the light reactions Light absorption and energy transfer The pathway of electrons Evidence of two light reactions Photosystems I and II ... Print this Table of Contents Shopping Price: USD $1495 Revised, updated, and still unrivaled. The Official Scrabble Players Dictionary (Hardcover) Price: USD $15.95 The Scrabble player's bible on sale! Save 30%. Merriam-Webster's Collegiate Dictionary Price: USD $19.95 Save big on America's best-selling dictionary. Discounted 38%! More Britannica products photosynthesis Page 1 of 36 The location, importance, and mechanisms of photosynthesis.

85. LeavesandPs In photosynthesis, plants get what two chemicals from the environment to Why do plants need carbohydrates? Oxygen produced in photosynthesis is a http://www.biology.iastate.edu/Courses/202L/New Site S05/26Leaf&Ps/ LeavesandPs.

Lab Topic 26 Investigating Leaf Structure and Photosynthesis Types of Leaves Simple Palmately compound Pinnateley compound Arrangement Pattern Alternate Opposite Whorled Venation Patterns Pinnate venation Palmate venation Parallel venation Leaf Variety New Pic A New Pic B New Pic C What type of leaf arrangements and venation do these various plants have? Which of the above has pinnately compound leaves? Which has palmately compound? Do you suspect that any of the above leaves are monocots? Which ones? Why do you say so? Can stems be photosynthetic? Are needles leaves? Why are leaves important? Through what structures in leaves do gas exchanges take place? How is this gas exchange regulated in the stoma? What is a petiole and what function does it serve? Is a monocot or dicot leaf more likely to have parallel veins? Is a monocot or dicot leaf more likely to have netted venation? Why are leaves important in water transport? Internal Leaf Anatomy Structure of a Dicot Leaf In the photo above, identify the epidermis, columnar mesophyll cells, spongey mesophyll cells, and the vascular bundle. Discuss the function of each.

86. Photosynthesis Animals are consumers; they cannot carry out photosynthesis. plants can makeenough glucose on a sunny day to last them through the night and through http://www.sambal.co.uk/photosynthesis.html

Sambal's Science Web Photosynthesis Home Up Green plants are producers . This means that they can survive without animals! They can make lots of organic chemicals from a few simple inorganic chemicals. They need simple things like carbon dioxide and water and can make complex things like sugar, starch, fat, and proteins. Plants get their nutrients from the environment. Carbon dioxide comes from the air (unless they are aquatic plants, in which case they get it from the water surrounding them). They get water from the soil. They also need other inorganic nutrients like nitrate, sulphate and phosphate. A few plants cannot get nitrate out of the soil so they have to eat animals to get the nitrogen which they must have for growth. Animals are consumers ; they cannot carry out photosynthesis. This means that they have to eat other things to get the carbohydrates, fats, proteins, vitamins and minerals which they need. When plants are in the sunlight they can make a sugar called glucose. This is slightly different from the sugar (sucrose) which you put into your tea. Glucose contains three chemical elements: Carbon Hydrogen Oxygen All the carbon needed for photosynthesis comes from carbon dioxide.

87. Photosynthesis: A Controlled Experiment starch increases the process of photosynthesis in the green plant. Mark plants A, B and C. 2. Put cardboard pieces at the bottom of each bag. 3. http://www.iit.edu/~smile/bi8904.html

Photosynthesis: A Controlled Experiment Coley, Juana 23 W. 143rd Street Rosa Parks Middle School Dixmoor, IL 60426 1-708-339-9550 1-708-385-4286 Objective To measure the amount of starch left in a leaf of a geranium plant under the following conditions; carbon dioxide increased, decreased and neither increased or decreased. To prove increased starch increases the process of photosynthesis in the green plant. Apparatus Needed 3 Geranium Plants (same size, shape and color) 3 2 gallon plastic bags with twist to close 2 250ml Beakers 1 500ml Beaker 1 Hot Plate 1 Pair of Plastic Tongues 4 Petri Dishes 1 1pt. 91% Isopropyl Alcohol 1 Package of Alka-Seltzer 1 50mL of Soda Lime 1 Bottle of Potassium Iodide 3 Pieces of Cardboard 1 Pitcher of Water Recommended Strategies Conclusion To determine how much starch is left under three conditions. 1. Carbon Dioxide increased. 2. Carbon Dioxide decreased. 3. Carbon Dioxide neither increased or decreased. Discussion 1. What were the results of plant A, with Alka-Seltzer? Was the carbon dioxide increased, decreased, or remained the same? 2. What were the results of plant B, with the soda lime? Was the carbon dioxide increased, decreased, or remained the same? 3. What were the results of plant C, the "control" plant? Was the carbon dioxide increased, decreased, or remained the same?

88. CSREES - USDA - Plants & Plant Products Through its plants and Plant Products programs, CSREES provides national Through photosynthesis, plants provide food, oxygen, and energy for the world. http://www.csrees.usda.gov/nea/plants/plants_all.html

Home Contact Us Site Map Search ... Newsroom National Emphasis Area Overview Through its Plants and Plant Products programs, CSREES provides national program leadership and funding opportunities for research, education, and extension to address various challenges for crop production and plant protection. These programs guide development and use of economically sound and environmentally friendly approaches and products for national needs such as food, feed, and fiber. CSREES Plant and Plant Product programs provide a better understanding of plants: how they grow, how their growth and productivity can be improved, and how they can be used in new ways. The combination of leadership and funding in Plants and Plant Product programs brings about development of new strategies and improvement of existing strategies for plant use and productivity. This increased understanding and forward thinking strengthens our nation’s ability to address challenges such as loss of arable land, increased population, protection of the nation’s food production, destruction of the environment, global climate change, and economic stability of rural and agricultural communities. Plants are diverse organisms, differing in size and shape and ranging from single cells such as algae to complex organisms such as trees. An important feature unique to plants is their ability to use energy from sunlight to produce their own food such as sugar, starch, and other carbohydrates; this process is termed photosynthesis. Through photosynthesis, plants provide food, oxygen, and energy for the world. Plants also provide fiber, medicines, building materials, and natural products such as oils and latex. Plants enliven and sustain our environments, providing flowers for indoor decoration, parks for recreation, and forests for wildlife.

89. Populations And Ecosystems 6G1 plants must have chlorophyll (Green pigment) for photosynthesis to take place . plants provide oxygen to people and animals through photosynthesis. http://www.utm.edu/departments/cece/old_site/sixth/6G1.shtml

SIXTH GRADE SCIENCE Environmental Science Populations and Ecosystems 6G1.00 Unifying Concepts of Science Scale and Model 2.1 c CURRICULAR CORRELATIONS GRADE: Sixth CONTENT STANDARD: Environmental Science CONTENT TOPIC: Populations and Ecosystems CONCEPT: Photosynthesis and cellular respiration are life-sustaining plant processes. CONTENT OBJECTIVE: 6G1.00 To understand how the process of photosynthesis changes sunlight into stored chemical energy by producers INSTRUCTIONAL OBJECTIVES: The learner will: 1.01 define photosynthesis. 1.02 analyze the process of photosynthesis. 1.03 explain the importance of photosynthesis in the life process. 1.04 define cellular respiration. 1.05 illustrate how food is broken down to release energy. 1.06 compare respiration and photosynthesis to determine how they complement each other. OUTLINE OF CONTENT: I. Photosynthesis A. Define B. Analyze the process II. Life process - Photosynthesis A. Importance B. Oxygen C. Carbon dioxide III. Define cellular respiration

90. Holbrook Travel Educational Expeditions - PASCO_photosynthesis Through the process of photosynthesis, plants harness light energy from the sunand turn it into chemical energy. In this process, green plants use sunlight http://www.holbrooktravel.com/pages/educationexpeditions/PASCO_photosynthesis.as

©Holbrook Travel, Inc. 2004 IMPORTANT LEGAL NOTICE: Holbrook Travel believes all information to be accurate at the time of publication. However, we reserve the right to make corrections. Educator Resources Photosynthesis Equipment Set-up Data Collection Procedure Data Analysis Conclusions and Extensions Purpose: In this experiment, we will use the Dissolved Oxygen (DO2) Sensor to measure and determine any difference in the level of DO2 in water, using plants of different types and sizes. We’ll also see if increasing or decreasing light intensity has an effect on rate of photosynthesis and DO2 levels Background Information: Through the process of photosynthesis, plants harness light energy from the sun and turn it into chemical energy. In this process, green plants use sunlight to convert carbon dioxide (CO2) dissolved in water to sugars and oxygen. In the case of aquatic plants, the oxygen produced can be dissolved in the water and can then be used by fish and other aquatic organisms. In addition to the amount and type of plants in a waterway, light intensity is another key factor of importance for photosynthesis. Certain wetland environments around the world are experiencing severe losses in underwater vegetation. A decrease in intensity of light is one possible factor that could be responsible for this vegetation loss.

91. Dr. Botnic - Photosynthesis During the process of photosynthesis, plants use that energy to convert carbondioxide and water into the simple sugar glucose and oxygen. http://www.windowbox.com/cgi-bin/experts/DisplayArticle.asp?TopicID=1&ArticleID=

92. Lesson Plans - Photosynthesis, Trees, And The Greenhouse Effect What is the sun s role in photosynthesis? Answer plants convert the sun s energyinto a sugar called glucose, which is the main source of plant nutrition. http://www.nationalgeographic.com/xpeditions/lessons/08/g68/brainpopphoto.html

Check out: X8: The Eco-Cycle Standard #8: The characteristics and spatial distribution of ecosystems on Earth's surface Be an Explorer Every Day! ... Preserving Biodiversity Photosynthesis, Trees, and the Greenhouse Effect Are Hammerheads a Keystone Species? Bioluminescence: Living Light Can You Hear a Whale? Climate Controls Competition on Sable Island Crocs, Then and Now DNA and Endangered Species Dugongs, Elephants, and Evolution Everyday Explorers: Investigate! From Wolf to Woof Harvesting the Ocean for Medical Science Kings of the Kalahari Leopard Seals and Penguins: A Delicate Balance Microclimate in the Schoolyard Pilot Whales' Social Behavior Postcards from the Edge: Endangered Species Solving the Sea Turtle Mystery The Antarctic Ecosystem: Where Would It Be Without Krill? Using Venn Diagrams to Compare Two Ecosystems Water Column Mix-Up Why Preserve Biodiversity? Why Study Nurse Shark Mating? Complete Index Photosynthesis, Trees, and the Greenhouse Effect Overview: In this lesson, students will study photosynthesis and then transfer their understanding of this topic to a consideration of how trees can help reduce the negative impacts of the greenhouse effect. They will read a Web page describing the greenhouse effect, carbon dioxide's role as a greenhouse gas, and the role of humans in exacerbating this effect. Students will also browse the Web site of an organization that sponsors tree planting programs and consider how these programs might help reduce or slow down the increase of the greenhouse effect. They will conclude by writing paragraphs telling younger kids about the benefits of trees and plants.

93. NOVA Online | Methuselah Tree | Illuminating Photosynthesis photosynthesis in plants and a few bacteria is responsible for feeding nearlyall life We exhale the carbon dioxide that plants need for photosynthesis. http://www.pbs.org/wgbh/nova/methuselah/photosynthesis.html

window.self.name = "phot_parent"; Go to Illuminating Photosynthesis Flash required Illuminating Photosynthesis By Rick Groleau Photosynthesis in plants and a few bacteria is responsible for feeding nearly all life on Earth. It does this by taking energy from the sun and converting it into a storable form, usually glucose, which plants use for their own life processes. Animals that consume plants also make use of this energy, as do those that consume those that consume plants, and so on to the top of the food chain. As important a job as making all of the world's food is, there's another vital function that photosynthesis performs: It generates the oxygen that oxygen-breathing animals need to survive. But here we animals repay the favor. We exhale the carbon dioxide that plants need for photosynthesis. This feature takes a look at the oxygen/carbon dioxide cycle and at the process of photosynthesis. Also included are a few puzzlers with answers that may surprise you. Illuminating Photosynthesis Requires Flash Illuminating Photosynthesis (non-Flash version) Flash is a plug-in that allows for increased interactivity. If you can see the animated boxes at left, the plugin is already installed. If you do not see the boxes, you can

94. Tips For Dissolved Oxygen - Tech Tips: ® LaMotte Company photosynthesis. In the leaves of plants one of the most important chemical Since photosynthesis requires light, plants do not photosynthesize at night, http://www.lamotte.com/pages/common/techtips/dotip.html

Tech Tips: Tips for the testing of Dissolved Oxygen: Dissolved Oxygen Oxygen is critical to the survival of aquatic plants and animals, and a shortage of dissolved oxygen is not only a sign of pollution, it is harmful to the fish. Some aquatic species are more sensitive to oxygen depletion than others, but some general guidelines to consider when analyzing test results are: 5-6 ppm Sufficient for most species Stressful to most aquatic species Fatal to most species Where Does The Oxygen Come From? The oxygen found in water comes from many sources, but the largest source is oxygen absorbed from the atmosphere. Wave action and splashing allows more oxygen to be absorbed into the water. A second major source of oxygen is aquatic plants, including algae; during photosynthesis plants remove carbon dioxide from the water and replace it with oxygen. Absorption: Photosynthesis: In the leaves of plants one of the most important chemical processes on Earth is constantly occurring- photosynthesis. During daylight, plants constantly take carbon dioxide from the air, and, in the presence of water, convert it to oxygen and carbohydrates, which are used to produce additional plant material. Since photosynthesis requires light, plants do not photosynthesize at night, so no oxygen is produced. Chemically, the photosynthesis reaction can be written as: Light + nCO + nH O (CH O) n + nO Light + Carbon Dioxide + Water Carbohydrate + Oxygen Where Does The Oxygen Go?

95. Carotenoids In Light Harvesting Complexes Higher plants capture light for photosynthesis with the help of plants, algaeand photosynthetic bacteria, have developed efficient systems to harvest http://www.leffingwell.com/lhc.htm

Carotenoids Carotenoids in Light Harvesting Complexes Lutein-5,6-epoxide Abscisic Acid (Plant Growth Regulator - an abscission accelerating plant hormone) Neoxanthin The following links provide a more in depth review of LHC's: LIGHT HARVESTING COMPLEX II -stunning photographs from NATURE of the molecular structure Chloroplast light-harvesting complex II - A chime model Light Harvesting in Bacterial Photosynthesis - an excellent overview Back to The Carotenoids Page Home Back to In the News In the News ... Smoke Flavor II. - Dark Fire-Cured Tobacco

96. College Of Chemistry Newsjournal, Fall 2004 What is not obvious is how to translate the plants’ ability to meet their The primary chemical step in photosynthesis takes place inside what is called http://chemistry.berkeley.edu/editor/Publications/journal/volume12/no2/fleming.h

Back to News and Publications pdf version Fall 2004 Features Dean's Desk News from Chemical Engineering News from Chemistry In Praise of Lewis and Seaborg Alumni Relations Alumni Association News Class Notes Alumnus Profile: Stan Williams Alumni Questionnaire Faculty Highlights Interdisciplinary education: When fields intersect How Small is Too Small Faculty Profile: Elton Cairns Faculty Profile: Graham Fleming College and Campus News Berkeley Newscenter credits Spring 2004 Fall 2003 ... all NewsJournals Faculty Profile: Graham Fleming Professor Graham Fleming Plants. Solar energy. The connection is obvious. What is not obvious is how to translate the plants’ ability to meet their energy needs from sunlight to the human scale. Luckily, Graham Fleming is working on that translation. Fleming spends much of his time using lasers to observe super-fast events, such as the main energy transfer steps in photosynthesis, the process of using the energy from sunlight to convert carbon dioxide and water into oxygen and carbohydrates. “Understanding how plants convert sunlight into usable energy is a fascinating challenge with very practical applications,” he said.

97. Oceans Alive! | Life In The Sea | Life Near The Surface Through photosynthesis, plants manufacture organic materials (food) from inorganicmaterials (water, carbon dioxide, and nutrients) using sunlight as their http://www.mos.org/oceans/life/surface.html

The Living Sea Life Near the Surface The sea is home to billions of plants and animals. Many live only near the sunlit surface. Here you'll find everything from microscopic plankton to the giant blue whale. Oceanographers classify marine organisms by separating them into two primary groups: plants and animals. Ocean Plants Images from data collected from satellites show densities of phytoplankton in the Atlantic Ocean. Red shows where phytoplankton is densest, followed by yellow, green, blue and violet where it is least dense. Phytoplankton's spring bloom (shown right) occurs when days are longer and more nutrients come up from the bottom. There are two general types of plants found in the ocean, those having roots that are attached to the ocean bottom and those not having roots which simply drift about with the water. The rooted plants in the ocean are only found in shallow water because there is not enough sunlight to sustain photosynthesis in deeper waters. Since sunlight does not penetrate more than a few hundred feet into the ocean, most of the ocean is not capable of supporting rooted plants. Nevertheless, plants are found throughout most of the oceanic surface waters. The most abundant plants in the ocean are known as phytoplankton. These are usually single-celled, minute floating plants that drift throughout the surface waters of the ocean. A bucket of sea water might hold a million microscopic diatoms which are relatives of seaweed encased in glassy boxes. To grow, phytoplankton need nutrients from the sea water and lots of sunlight. The most light occurs in the tropics but nutrients there, especially nitrogen and phosphorus, are often in short supply. When large quantities of diatoms and other phytoplankton are present they give a color to the sea. Spectacular phytoplankton blooms are found in cooler waters where nutrients are brought up from the sea floor during storms.

98. Photosynthesis Leaf CrossSection photosynthesis takes place primarily in plant leaves, andlittle to none occurs in stems, etc. The parts of a typical leaf include the http://biology.clc.uc.edu/courses/bio104/photosyn.htm

Photosynthesis Photosynthesis is the process of converting light energy to chemical energy and storing it in the bonds of sugar. This process occurs in plants and some algae (Kingdom Protista). Plants need only light energy, CO , and H O to make sugar. The process of photosynthesis takes place in the chloroplasts , specifically using chlorophyll , the green pigment involved in photosynthesis. Photosynthesis takes place primarily in plant leaves, and little to none occurs in stems, etc. The parts of a typical leaf include the upper and lower epidermis , the mesophyll , the vascular bundle(s) (veins), and the stomates . The upper and lower epidermal cells do not have chloroplasts, thus photosynthesis does not occur there. They serve primarily as protection for the rest of the leaf. The stomates are holes which occur primarily in the lower epidermis and are for air exchange: they let CO in and O out. The vascular bundles or veins in a leaf are part of the plant's transportation system, moving water and nutrients around the plant as needed. The mesophyll cells have chloroplasts and this is where photosynthesis occurs. As you hopefully recall, the parts of a chloroplast include the outer and inner membranes, intermembrane space

99. Unit Five UNIT FIVE photosynthesis PLANT STRUCTURES. photosynthesis / Natural Products.Plant Classification / Plant Structures. Textbook Reading Guides http://www.mvhs.fuhsd.org/tim_krieger/apbio/Units/unitfive.htm

COURSE DOCS Greensheet Back to School Night (parents) CALENDAR / UNITS Go to Schoolloop! HISTORY Class Photos Monta Vista AP Results Timeline of MV AP Bio LINKS Biology Links MV Journal of Biology Citation Machine Schoollloop.com ... Study Skills AP EXAM INFORMATION General Exam Information College Board Photosynthesis / Natural Products Plant Classification / Plant Structures Textbook Reading Guides -Ch. 20 (Plant Classification) -Ch. 32, 33A-C (Plant Structures) Practice Quizzes -Photosynthesis and Natural Products Practice Quiz -Photosynthesis and Natural Products Practice Quiz Key Supplemental Readings (required) Ocean Plant Life Slows Down and Absorbs Less Carbon Supplemental Links (not required) -Online Tutorials, Quizzes, Etc on Photosynthesis -Photosynthesis Animation - Light Reactions -Photosynthesis Animation - Light Reactions Interactive -Animation of the Calvin Cycle ... -Ferns Lectures -C4/CAM Photosynthesis, Dissolved Oxygen (Lakes), and Natural Products (1/24/05)

100. ANATOMY 3 photosynthesis requires CO2 ; in order to obtain it stomata must open and the source of sugars produced in photosynthesis and other plant structures, http://www.hcs.ohio-state.edu/hcs300/pstrans.htm

Site Index TRANSLOCATION Plants need a lot of water. Young Brassica oleracea plants take up an amount of water equal to their shoot weight in about 5 hours - if that applied to me I would have to drink 3 gallons of water an hour to stay alive! Why are they in this position? Photosynthesis requires CO2 ; in order to obtain it stomata must open and the escape of water cannot be avoided. Opening is a blue light response and involves accumulation of sugars, organic acids and potassium to increase osmotic pressure. The guard cells take up water, increasing turgor pressure against the epidermal ground cells. In the dark or under water stress conditions guard cells lose their solutes and stomata close. Rubisco has a low affinity for CO2, so stomata usually have to be wide open in order for photosynthesis to occur. Plants have developed two solutions to this problem. Crassulacean acid metabolism (CAM) Succulent plants (Cactaceae, Crassulaceae and Euphorbiaceae) that grow in dry environments open their stomata at night and combine CO2 with phosphoenol pyruvate (3 carbons) to make malic acid (4 carbons). In the day-time with the stomata closed, malic acid is broken down to pyruvate and CO2, which is fixed by the Calvin cycle into sugars.

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