Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Wellsway School Science Team Curriculum 2006 Triple Science - Biology workbook PLANT TRANSPORT WORKBOOK Name:_________________ Tutor Group:____________ 1 Wellsway School Science Team Transport and Water Relations Curriculum 2006 Triple Science - Biology workbook 1. HOW PLANTS TAKE UP WATER & TRANSPIRE 1. OBJECTIVES: Do plants have a circulatory system? How are substances carried throughout a plant? What evidence is there for this transport? What substances do plants need? By the end of this topic you should: (a) Understand the role of osmosis and transpiration in the movement of water through a plant. (b) Observe root hairs; investigate water loss in plants using a bell jar, nail varnish replicas to show stomata, the use of a simple potometer to demonstrate water uptake. (c) Know the role of xylem and phloem in transport within plants and carry out an investigation into the movement of a dye through the xylem. (d) Appreciate that modelling may be used to understand how processes may work as illustrated by the representation of areas of a plant by the model proposed by Munch and the uses and limitations of the model (details of Mass Flow hypothesis not required). (e) Know the importance of water to plants and its use in photosynthesis, transport of minerals and support. (f) Know that for healthy growth plants require nitrate, potassium and phosphate. (g) Observe the effects of minerals on plant growth. 2. Investigating water transport in the xylem. a. Stand a stick of celery* in a beaker containing about 1 cm depth of coloured dye. *(ideally with some leaves still attached – the celery we eat is a leaf stalk). b. Leave it for at least 45 minutes (while you are waiting, continue with section 3). c. Remove from the dye and lay the stalk on a tile or paper towel. d. Carefully cut across the stalk 20 mm from the bottom and observe the cut end. e. Sketch this cut end in the space below and label it to show the distribution of the coloured dye, and write the name of the tissue where most of the dye is found. f. Repeat step c. at 20 mm intervals up the stalk until no dye can be seen (or until you reach the leaves). Estimate the distance travelled by the dye in the time you left it soaking and calculate the rate of uptake of dye (in mm / minute). Drawing of cut end of celery: Distance travelled by dye (mm): Time celery stalk was in the dye (mins): Rate of uptake of coloured dye (mm / minute): How do you think this rate compares with the normal uptake of liquids by an intact celery plant? Support your answer with reasons: 2 Wellsway School Science Team 3. Curriculum 2006 Triple Science - Biology workbook If appropriate, watch the video, MSS presentation or PowerPoint on plant transport. Read your textbook or support material on plant transport. Discuss with your teacher what a plant transports, why & how. a. Write down a list of materials transported in a plant. Include where they are transported from, and where they are transported to. 1. Water. Soil water roots xylem stem leaf air 2. Mineral ions (N,P,K). Soil water roots xylem stem leaf. 3. Carbon dioxide. Air stomata air spaces leaf cells. 4. Oxygen. leaf cells air spaces stomata Air. 5. Dissolved food. E.g. glucose, sucrose, amino acids. Leaves phloem stem flowers roots (also storage organs). b. Suggest reasons why plants have a transport system like animals, but no pump (heart) unlike animals. Animals need much more energy (for movement) which could not be supplied quickly enough without a pump. 4. Make a fully labelled and annotated drawing to show the distribution of transport tissues in a ROOT (colour in the xylem in red & the phloem in blue): 5. Make a fully labelled and annotated drawing to show the distribution of transport tissues in a STEM (colour in the xylem in red & the phloem in blue): 3 Wellsway School Science Team 6. 4 Curriculum 2006 Triple Science - Biology workbook Make a fully labelled and annotated drawing to show the distribution of transport tissues in a LEAF(colour in the xylem in red & the phloem in blue) : Wellsway School Science Team 7. Curriculum 2006 Triple Science - Biology workbook If you have finished…. Describe how the structure of xylem and phloem tissue makes them suitable for carrying out their functions of transporting materials around a plant (use labelled & annotated drawings to help you if you wish): Xylem 1. D_______, hollow cells with no e_____ walls. Forms an unbroken cyl__________ from root to stem to leaf; 2. Small lumen (cav_______). Enables an unbroken column of water to form; 3. Supported by lignin (W_______!). Stops it from collapsing. Phloem 1. Living cells which can control movement of food by ACTIVE TRANSPORT; 2. End walls perforated with pores, again to control the movement of food; 3. Small COMPANION CELLS beside the phloem elements provide ENERGY for active transport. 8. Uptake of water in the root. If possible, observe the roots of a plant, and the tiny root hairs which grow out from the walls of the roots. Discuss with your teacher how water (and mineral ions) are absorbed from the soil, across the root tissues and into the xylem. In the space below, make a clear, labelled drawing to show the pathway of water (and mineral ions) across a root to the xylem: B4U, PAGE 226, MIDDLE DIAGRAM Using your knowledge of osmosis, EXPLAIN clearly how water is able to pass across the root in this way (useful terminology: soil water; cell sap; high / low; water potential; selectively permeable membranes): Soil water normally has a H_________ water potential (i.e. there’s more water there!) than the C_______ S______ inside the root cells. So water passes across the selectively permeable membranes of the root hair cells by O__________ (from higher to lower water potential), so the cells g________ water. Water passes right across the root in the same way, until it enters the X___________ vessels. 5 Wellsway School Science Team 9. Curriculum 2006 Triple Science - Biology workbook Transpiration and the transport of water through the stem and leaf. a. Observe the 2 potted plants which were set up 24 hours ago. Note that both pots are covered with polythene bags, but only plant A is covered with a polythene bag (or bell jar). Complete the table below, which compares the loss in mass in each plant over 24 hours: Plant: Sketch of plant: A B Mass at start (g) Mass after 24 hours (g) Loss in mass (g) Effect of clear liquid in bag/jar on cobalt N/A chloride*: *(Cobalt chloride paper turns from blue to pale pink/white when water is added to it.) Write a conclusion, explaining the different results in the 2 plants: Conclusion: b. Write down a clear definition of transpiration: (B4U, PAGE 227) Transpiration is the LOSS of WATER from a plant, mainly through the microscopic pores on the underside of the leaves, called STOMATA. The loss takes place by E_____________ & D_________. 6 Wellsway School Science Team Curriculum 2006 Triple Science - Biology workbook 10. If possible, observe the leaf of a plant, and the tiny stomata (pores) which are found in the lower epidermis of the leaf. Discuss with your teacher how water (and mineral ions) are absorbed from the root xylem, up the stem, into the leaf xylem, and into the leaf cells. In the space below, make a clear, labelled drawing to show the pathway of water (and mineral ions) from the leaf xylem to the leaf cells. Show also the pathway of water vapour across the intercellular air spaces and out through the stomata: Using your knowledge of osmosis, EXPLAIN clearly how water is able to pass across the leaf in this way (useful terminology: water in xylem; cell sap; high / low; water potential; selectively permeable membranes; evaporation; water vapour; diffusion.): 4 bullet points at the bottom of p227, B4U. Also • Water is drawn across the leaf from the leaf xylem by O____________ (as water evaporates from spongy mesophyll cells, it decreases their W__________ P_____________, so water flows across the leaf). 7 Wellsway School Science Team Curriculum 2006 Triple Science - Biology workbook 11. If you have finished… Observing stomata: Make a nail varnish replica of the lower epidermis of a Tradescantia leaf, and observe it carefully under a microscope. Draw, label and annotate clearly what you see: Nice green stoma on p228, B4U! 12. Investigating the factors affecting transpiration. Watch the teacher demonstration of the potometer. a. Label and annotate the drawing below of a potometer: 8 Wellsway School Science Team Curriculum 2006 Triple Science - Biology workbook b. What is the purpose of the tap and reservoir? To return the air bubble to the “start”. c. What exactly does the potometer measure? The uptake of water by a cut shoot. d. Why can’t the potometer be used to measure, precisely, the rate of transpiration? Because they are not exactly the same: some water is used in PHS & some is used to keep cells turgid (swollen). e. Nevertheless, since water uptake is directly proportional to transpiration, the effect of varying different factors on the rate of transpiration can be investigated quite accurately with the potometer. Describe and explain the effect of each of the following 4 factors on the rate of transpiration. Draw sketch graphs to show exactly these affect transpiration rate: i. Wind speed / air movements: 9 ii. Humidity (water content of the air): iii. Temperature: Wellsway School Science Team iv. Curriculum 2006 Triple Science - Biology workbook Light intensity: If you have finished… Carry out a computer simulation which investigates the effects of the above factors on the rate of transpiration. If possible, record (or print out and attach) the results of the simulation. How do the results of the simulation compare with your explanations above? 13. Write a paragraph explaining the importance of water to plants. Make sure you refer to its use in photosynthesis, transport of minerals and support. 10 Wellsway School Science Team Curriculum 2006 14. The importance of mineral ions to plant growth. a. Observing the effects of minerals on plant growth. Look at the 5 tubes shown below. 11 Triple Science - Biology workbook Wellsway School Science Team Curriculum 2006 Triple Science - Biology workbook Distilled water No Potassium No No Phosphates Nitrates Construct a table highlighting the key differences in the growth of each seedling: TUBE NO 1 2 NO OF LEAVES lots, green few, yellow SIZE OF LEAVES large small small small middle-sized NO OF ROOTS lots few quite a lot few quite a lot medium small medium SIZE OF ROOTS large, long small 3 4 few, yellow few, yellow & purple 5 few, greenyellow b. Using your textbook, or support material, or the Internet, research and record the importance of the following 3 mineral ions to healthy plant growth: i. Nitrates. Growth of leaves & stems. Nitrogen needed for protein synthesis. Lack – stunted growth & yellow older leaves. ii. Potassium. Healthy leaves & flowers. Help reactions in Photosynthesis & respiration to work. Lack – yellow leaves with dead spots iii. Phosphates. Healthy roots. Help reactions in Photosynthesis & respiration to work. Lack – poor root growth & purple younger leaves. 12 Wellsway School Science Team Curriculum 2006 Triple Science - Biology workbook 15. Translocation. As well as transporting water and mineral ions from roots to stem to leaves, the plant also carries out translocation. a. Write a clear definition of translocation: The transport of dissolved foods from where they are made in the leaves to all other parts of the plant. Foods are carried in the PHLOEM, by ACTIVE TRANSPORT. b. Write down 3 key differences between translocation and the transport of water & mineral ions: TRANSLOCATION TRANSPORT of WATER, MINS. 1. In phloem, living tissue. In xylem, dead tissue. 2. Transported FROM leaves… Transported TO leaves… 3. …TO rest of plant. …from roots. 4. Transported by ACTIVE Carried in TRANSPIRATION TRANSPORT (needs energy). STREAM (no extra energy needed. c. Describe what happens to the food materials transported in the phloem. Refer to sugars, amino acids and fatty acids in your answer: Sugars: 1. Used for ENERGY, 2. Built up into STARCH, which is stored in SEEDS & STORAGE ORGANS, 3. Built up into CELLULOSE, which forms the CELL WALL 13 Wellsway School Science Team Curriculum 2006 Triple Science - Biology workbook Amino Acids: Built up into PROTEINS, for GROWTH Fatty Acids: built up into FATS (LIPIDS), & stored in SEEDS. If you have finished…. The Pressure (mass) flow hypothesis was a model proposed by Ernst Munch in 1930 that explained the mechanism of phloem translocation. Carry out Internet research to find out how the model helps to explain how food is transported around a plant. Summarise your findings in the space below (or print out a summary): http://answers.yahoo.com/question/index?qid=20080509110537AAGMKEV Best Answer - Chosen by Voters The mass flow hypothesis in terms of plants, is the following: The accepted mechanism needed for the translocation of sugars from source to sink is called the pressure flow hypothesis. As glucose is made at the source (by photosynthesis for example) it is converted to sucrose (a dissacharide). The sugar is then moved into companion cells and into the living phloem sieve tubes by active transport. This process of loading at the source produces a hypertonic condition in the phloem. Water in the adjacent xylem moves into the phloem by osmosis. As osmotic pressure builds the phloem sap will move to areas of lower pressure. At the sink osmotic pressure must be reduced. Again active transport is necessary to move the sucrose out of the pholem sap and into the cells which will use the sugar -converting it into energy, starch, or cellulose. As sugars are removed osmotic pressure decreases and water moves out of the phloem. So, the following is true and perhaps a more concise version, if you are learning it for an exam: The movement of sugars in the phloem begins in the leaves, where 14 Wellsway School Science Team Curriculum 2006 Triple Science - Biology workbook (a) Sugars are loaded (actively transported) into a sieve tube. Loading of the phloem sets up a water potential gradient that facilitates the movement of water into the dense phloem sap from the neighboring xylem (b). As hydrostatic pressure in the phloem sieve tube increases, pressure flow begins (c), and the sap moves through the phloem. Meanwhile, where food is being used up, e.g. roots, respiring cells: (d), incoming sugars are actively transported out of the phloem and removed as complex carbohydrates. The loss of solute produces a high water potential in the phloem, and water passes out (e), returning eventually to the xylem. 16. Well done! You have now completed the Plant Transport topic. Now you need to revise your work in preparation for the Plant transport test. 17 Useful web links: http://www.s-cool.co.uk/topic_index.asp?subject_id=17&d=0 http://www.bbc.co.uk/schools/gcsebitesize/biology/greenplantsasorganisms/ http://swgfl.skoool.co.uk/keystage4.aspx?id=315 (good on-line tutorial) http://www.chadevans.co.uk/asite/gcse/b02/t10.html http://www.revisionworld.co.uk/gcse-us-grades-8-10/biology/questions/longer-questions/question9-transpiration http://www.thestudentroom.co.uk/wiki/Revision:GCSE_Biology_-_Plant_Biology 18. Glossary. (Muddled – sort them out!) 1 Cell sap 2 Cobalt chloride paper 3 4 5 Culture solution Diffusion Evaporation 6 Mineral Ions 7 8 Nitrates Osmosis 9 10 11 Phloem Phosphates Photosynthesis 12 13 Potassium Potometer 14 15 16 17 Pressure flow hypothesis Root hair Selectively permeable Stomata 18 Translocation 15 Random movement of particles from high to low concentration. Change of state from liquid to gas, e.g. water to water vapour. Liquid found in all plant cells. Solution containing mineral ions needed for plant growth. Indicates the presence of water, by turning from blue to pale pink. Diffusion of water from high to low water potential, via a membrane Mineral ion needed for protein synthesis & plant growth. Tiny tubes used for carrying dissolved foods around the plant. Mineral ion needed for growth of roots & young leaves Any dissolved inorganic ion needed for healthy plant growth. Microscopic outgrowth of roots, important for absorbing water & mineral ions. Increase surface area of root. Munch’s model of how food is transported in the phloem. The process by which a plant makes it s own food from water & carbon dioxide, using sunlight energy. Mineral ion (metal) needed for healthy growth of leaves. Glass device which measures water uptake by a plant. Transport of dissolved foods around a plant. Tiny tubes which carry water & mineral ions from roots to leaves. A measure of the concentration of water in a solution. Wellsway School Science Team 19 Transpiration 20 Water potential 21 Xylem 19. 16 Curriculum 2006 Triple Science - Biology workbook Membrane which only allows smaller molecules to pass through it. Tiny leaf pores through which water vapour is lost by transpiration. Loss of water vapour from a plant, mainly through stomata. Wellsway School Science Team 20. 17 Curriculum 2006 Triple Science - Biology workbook Wellsway School Science Team 21. 18 Additional notes Curriculum 2006 Triple Science - Biology workbook Wellsway School Science Team Curriculum 2006 Triple Science - Biology workbook GCSE - WJEC 19