Working Document. The ForeST greenhouse. THEORETICAL CAPSULE (This document is intended for adults.)

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1 The ForeST greenhouse THEORETICAL CAPSULE (This document is intended for adults.)

2 It is important to know Theoretical capsule The objective of this capsule is to give the teaching personnel the opportunity to acquire a quick and accurate comprehension of what photosynthesis is. Activity 1 The characteristics of living organisms and the parts of plants Characteristics of living organisms Several characteristics allow for the distinction between a living organism and a non living organism. For primary school students, we will concentrate on the main characteristics. First, we will determine the characteristics that the students will automatically name: breathing feeding itself growing reproducing dying The suggested activities will allow two other characteristics to be brought to the forefront. It will be important to ensure they are named by the end of the LES: moving independently cellular organisation. Here are other characteristics of living organisms: reacting to changes in the environment adapting The number of characteristics varies from one source to the other depending on how they are grouped. A living organism must possess all the characteristics. Non-living organisms are mostly found in one of the following groups: air, water, light or earth. The Allô prof library contains a capsule (in French only) that may guide you. Here you will find a description of living organisms as well as examples of living and non-living organisms.

3 Parts of the plant The roots Usually below ground, the roots allow the plant to affix itself to the earth and to draw from it the elements that it needs (water, minerals salts) to feed itself. The roots also allow the sap to circulate, acting somewhat like a pump. They also are used to store nutrients for hard times. The stem The stem is the main part of the plant. The part of the plant located at the earth level is called the collar. The part where a leaf is affixed is called the node. The stem's function is to support the other parts of the plant. It also makes the nutrients (sap) circulate throughout the plant. The leaves The leaf is a part of the plant affixed to the stem. Photosynthesis occurs in the leaves. It is also through the leaves that the plant breathes at night. The flower The reproductive organs of plants are found in the flower. It has the male organ (stamen) or the female organ (pistil) (unisexual) or sometimes even both sexes (hermaphrodite). The fruit The fruit is formed by the plant after the flower, to protect the seeds it produces. The seed The seed will one day become another plant.

4 Activity 2 What is photosynthesis? PHOTOSYNTHESIS: In plants, photosynthesis ensures food production. In other words, photosynthesis is the capacity of a plant to transform organic matter from carbon dioxide (CO2), water (H2O) and solar energy. This energy, coming from the Sun, allows the leaf containing chlorophyll to transform the carbon dioxide from the air, and the water and mineral salts from the earth, into sugar (glucose). Finally, photosynthesis also produces oxygen, used for living organisms to breathe. Photosynthesis Carbon dioxide (CO2) Energy Phloem sap (sugar towards the roots) Oxygen (O2) Xylem sap (water + mineral salts towards the leaf)

5 Here is an equation that explains the main principles of photosynthesis as well as an analogy to a cake recipe. Ingredients Energy Result Cast off H2O + minerals salts + CO2 + sugar + O2 Milk + flour + eggs + Oven Cake + vapour (cast off) And breathing? It is important to mention that all parts of a plant (the roots, stem, leaves, flowers and fruit) breathe. Air exchanges mainly take place in regularly dispersed small openings called stoma (under the leaves). Breathing takes place regularly day and night, unlike photosynthesis, which only takes place by day. The sugar produced during photosynthesis is stored by the plant cells and during respiration the sugar is burned by the oxygen. The combustion of sugar (glucose) produces energy, water vapour (H2O) and carbon dioxide (CO2). This energy will be used in plant reproduction and growth, and will help it to accomplish its other activities. Here is a chemical equation that explains the principle of cellular respiration of the plant: Sugar + O2 Energy + CO2 + H2O

6 Perspiration Just like humans and animals, plants perspire. The plant thus loses water in the form of vapour. In plants, this phenomenon occurs day and night. Plant perspiration is essential to photosynthesis. Three factors influence plant perspiration on our planet, namely temperature, light and wind. What is chlorophyll? CHLOROPHYLL: Chlorophyll is a coloured pigment present in plants. This pigment plays a primordial role in photosynthesis in plants. Thus, when plants (their leaves) are exposed to the light of the Sun, it is chlorophyll, the pigment present in some of its cells, that absorbs the light. The plants then use the light, the water absorbed by their roots and the carbon dioxide absorbed by the leaves, to produce glucose. Glucose is the name of the sugar that feeds plants. Once this sugar has been produced in the leaves, it is transported by the sap towards the other parts of the plant (roots, stem) to feed it. In ecology, it is said that plants are "producers" (autotrophic living organisms) because they use their leaves to make their own food. What is sap? SAP: Sap is a liquid that circulates thanks to specialised cells called "vessel elements" between the various parts of the plant in order to transport the nutrients necessary to growth. There are two types of sap: xylem sap and phloem sap. Xylem sap (before photosynthesis) is a solution of mineral salts, absorbed by the roots and that mainly circulates in the xylem, or the vessels in the wood. These wood vessels have the capacity to transport great quantities of water and nutrients from the ground all the way to that photosynthesis factory: the leaves. Phloem sap (or feeding) (after photosynthesis) comes mainly from the leaves following the photosynthesis carried out by the plant. This sap circulates mainly in the phloem. It contains soluble organic substances, for instance amino acids and sugars.

7 It is interesting to note that it is phloem sap that man gathers to make sweet products. Here are some examples: birch sap (syrup, wine, beer, vinegar), sugar palm sap (supplies palm wine), gum arabic (or acacia) (chewing gum, Turkish delight, dragées). Finally, contrary to popular belief, maple syrup is made not from phloem sap (sap produced after photosynthesis) but rather from the xylem sap of the maple in springtime, even before photosynthesis has resumed its activity. The following diagram shows the location of the vessels of a tree trunk through which the sap circulates. Bark Phloem Xylem Marrow Source :

8 Some collective demonstrations! Do plants perspire? Materials: Protocol: o A green plant o A plastic bag To carry out this experiment, using the plastic bag, you need only hermetically cover the plant for a few days. You can then observe the droplets of perspiration that form on the plastic bag. For more details and photos, refer to the preparation guide, page 2. The production of oxygen (O2) by plants Materials: o 2 small fresh aquatic plants (e.g. elodea, also called water weed or pond weed); o 2 big beakers (ideally 1000 ml), 2 funnels, 2 test tubes; o 1-100w lamp; o 1 cardboard box to create obscurity; To learn about the protocol and the preparation technique, please refer to pages 3 to 5 of preparation guide.

9 Activity 3 tropisms The Online Universalis Encyclopaedia defines tropism thus: "In plants, tropism, (from Greek tropein: to turn) is a modification of the direction of growth, that is a curvature caused by an exterior stimulus and in relation to the direction of the stimulus." You may consult pages 6 to 8 of the preparation guide in order to familiarise yourself with the materials necessary to the preparation of various assemblies if you wish to have them in class, rather than using photos. There are various tropisms in plants. In primary school, we concentrate on phototropism, geotropism and hydrotropism. Phototropism or heliotropism The stimulus is light. You can see phototropism when the leaves move towards a light source. Geotropism or gravitropism The stimulus is weight. The roots moving downwards and the stems moving upwards are the result of geotropism. Hydrotropism The stimulus is water. Hydrotropism can be observed when we see roots moving towards the damp side of the assembly. To go a little further...: Haptotropism ou thigmotropism The stimulus is a contact. A climbing plant that rolls itself around a trellis represent this tropism quite well.

10 Activity 4 Extraction of chlorophyll by chromatography The objective of this activity is to experience an experiment that will allow you to show that there are a variety of pigment colours in a plant leaf. Pages 9 to 15 of the preparation guide give you various information related to this laboratory: laboratory materials list, everyday usage materials, labels... Chromatography is a technique that allows a homogenous mixture to be separated. In order to demonstrate that a variety of pigment colours exist in the leaves of a plant, we must extract the chlorophyll from the leaf. In other words, to separate the coloured elements (the pigments) from our leaf and to make them move (or spread) onto a piece of chromatographic paper. The principle is simple: to proceed with the separation and migration of the coloured pigments from our leaf, we need a strip of filter paper or chromatographic paper whose end is soaking in a liquid mixture (the solvent (alcohol) and a colour pigment (chlorophyll)). The elements of the mixture that dissolve better in the solvent will then migrate quickly to the paper, while those that have a lower solubility will migrate less quickly or not at all. In the laboratory in activity 4, we will use chromatography in order to find out what types of pigments are contained in the leaves we have chosen. Types of chlorophyll and colour Carotene : Yellowish - orange Chlorophyll a : Bluish - green Chlorophyll b : Greenish - yellow Xanthophyll : Yellow Video link: 05/Cellule_et_evolution/1.La_Cellule/Chromatographie/cromos.htm

11 Here are websites that allow for the exploration of other facets of plants Canadian Space agency (characteristics of living organisms and tropisms) Natural Resources Canada In French only : A diagram of a plant with definitions Maison Léon Provancher - Green life - various activities La main à la pâte (Does the water go up the plant? sequence of activities La main à la pâte (Where does the water from the watering can go? sequence of activities Activities relating to photosynthesis: Resources in chemistry and (Extraction of chlorophyll) Resources in chemistry and (Oxygen production) In French only : ScienTIC Flash animations related to photosynthesis: In French only: Cité des sciences (Animation flash de la photosynthèse) BrainPop