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Section Outline

Section Outline. Section 23-1. 23–1 Specialized Tissues in Plants A. Seed Plant Structure 1. Roots - absorb water and dissolved nutrients, anchor plants in the ground, hold soil in place, defend roots from bacteria and fungi.

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Section Outline

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  1. Section Outline Section 23-1 • 23–1 Specialized Tissues in Plants A. Seed Plant Structure 1. Roots - absorb water and dissolved nutrients, anchor plants in the ground, hold soil in place, defend roots from bacteria and fungi. 2. Stems - support system for the plant body, transport system that carries nutrients, a defense system that protects against predators and disease. 3. Leaves - main photosynthetic systems, contain subsystem to protect against water loss and allow gas exchange.

  2. Section Outline Section 23-1 • 23–1 Specialized Tissues in Plants • Plant Tissue Systems C. Dermal Tissue - outer covering of a plant D. Vascular Tissue - forms a transport system of water-conducting tissue (xylem) and food-conducting tissur (phloem) 1. Xylem - tracheids and vessel elements 2. Phloem - sieve tube elements and companion cells E. Ground Tissue - cells that lie between the dermal and vascular tissue • Plant Growth - many plants produce new cells at the tips of their roots and stems • Meristematic Tissue - is undifferentiated (not specialized) and the only plant tissue that produces new cells by mitosis

  3. Dermaltissue Meristematictissue Vasculartissue Groundtissue Epidermalcells Parenchymacells Collenchymacells Schlerenchymacells Xylem Phloem Companioncells Vesselelements Sieve tubeelements Tracheids Concept Map Section 23-1 Plant Tissues include includes includes includes includes includes

  4. Figure 23–1 Root, Stem, and Leaf Tissues Section 23-1 Leaf Stem Root Dermal tissue Vascular tissue Ground tissue

  5. Section Outline Section 23-2 • 23–2 Roots • A. Types of Roots - tap root and fibrous roots • B. Root Functions • 1. Uptake of Plant Nutrients • 2. Active Transport of Minerals • 3. Movement Into the Vascular Cylinder - both osmosis and active transport move water and minerals into the vascular cylinder. This ensures a one-way movement • 4. Root Pressure - is the starting point for the movement of water through the vascular system. Root pressure forces water upward allowing more water to be absorbed by the roots.

  6. Essential Plant Nutrients Section 23-2 Nutrient Nitrogen Phosphorus Potassium Magnesium Calcium Role in Plant Proper leaf growth and color; synthesis of amino acids, proteins, nucleic acids, and chlorophyll Synthesis of DNA; development of roots, stems, flowers, and seeds Synthesis of proteins and carbohydrates; development of roots, stems, and flowers; resistance to cold and disease Synthesis of chlorophyll Cell growth and division; cell wall structure; cellular transport; enzyme action Result of Deficiency Stunted plant growth; pale yellow leaves Poor flowering; stunted growth Weak stems and stunted roots; edges of leaves turn brown Thin stems; mottled, pale leaves Stunted growth; curled leaves

  7. Figure 23–7 The Structure of a Root Endodermis Root hairs Ground tissue (cortex) Phloem Epidermis Xylem Endodermis Vascular cylinder Zone of maturation Zone of elongation Apical meristem Root cap Section 23-2 Epidermis Ground tissue(cortex) VascularCylinder Cross Section of Plant Root(magnification: 40x)

  8. Figure 23–9 Water Transport in a Root Section 23-2

  9. Section Outline Section 23-3 • 23–3 Stems • Stem Structure and Function Stems have three important functions • They produce leaves branches and flowers • They hold leaves up to the sunlight • They transport substances between the roots and leaves

  10. Compare/Contrast Table Section 23-3 Comparing Primary and Secondary Growth of Stems Characteristics Where It Occurs Effect on Plant How It IsProduced Primary Growth Secondary Growth At ends of plants Increases plant length By cell division in the apical meristem In stem Increases stem width By cell division in meristems other thanthe apical meristem

  11. Figure 23–15 Layers of a Tree Trunk Contains old, nonfunctioning phloem that protects the tree Produces protective layer of cork Contains old, nonfunctioningxylem that helpssupport the tree Transports sugars produced by photosynthesis Produces new xylem and phloem, which increase the width of the stem Contains active xylem that transports water and minerals Section 23-3 Wood Bark Cork Xylem:Heartwood Cork Cambium Phloem Vascular Cambium Xylem: Sapwood

  12. Interest Grabber Section 23-4 • Leaves—Up Close and Personal • Leaves absorb light and carry on most of the photosynthesis that occurs in a plant. For this reason, leaves are important plant structures.Examine the drawings of the three types of leaves shown in the next slide.

  13. Easternwhite pine Dandelion Pin oak Interest Grabber continued Section 23-4 1. Describe the shape of each leaf. 2. Describe the features of each leaf. 3. How is the structure of a leaf related to its function?

  14. Section Outline Section 23-4 • 23–4 Leaves • Leaf Structure - optimized for absorbing light and carring out photosynthesis 1. Stomata - pore like openings on the underside of leaves 2. Guard cells - specialized cells surrounding the stomata by reacting to water pressure B. Leaf Functions 1. Photosynthesis - mostly takes place in the specialized ground tissue of the mesophyll. 2. Transpiration - loss of water through leaves (tree sweat) 3. Gas Exchange - plants keep their stomata open just enough to allow photosynthesis to take place but not so much that they lose an excessive amount of water.

  15. Function of Guard Cells Section 23-4 Guard cells Guard cells Inner cell wall Inner cell wall Stoma Stoma Open Stoma Closed

  16. Function of Guard Cells Section 23-4 Guard cells Guard cells Inner cell wall Inner cell wall Stoma Stoma Open Stoma Closed

  17. Figure 23–18 The Internal Structure of a Leaf Section 23-4 Cuticle Veins Epidermis Palisademesophyll Xylem Vein Phloem Spongymesophyll Epidermis Stoma Guardcells

  18. Interest Grabber Section 23-5 • Forces of Attraction • Molecules of a substance are attracted to one another by a force called cohesion. Molecules of different substances are attracted to one another by a force called adhesion. Use this information to answer the following questions.

  19. Interest Grabber continued Section 23-5 1. When the end of a narrow tube is placed in water, the water rises in the tube to a level that is higher than the water outside the tube. Which force causes this to occur? 2. How might this force cause water to rise in the stem of a plant? 3. When water molecules evaporate from the surface of a leaf, how do the forces of adhesion and cohesion resist this action? 4. When water molecules evaporate from the surface of a leaf, which force would cause other water molecules to move upward in the plant and follow the evaporating water?

  20. Section Outline Section 23-5 • 23–5 Transport in Plants • 2. Transpiration - the evaporation of water through the leaves pulls the water up the xylem by transpiration pull • 3. Controlling Transpiration - when water is abundant it flows into the leaves raising water pressure in the guard cells, and opening the stomata. When water is scarce the pressure in the guard cells lowers causing the stomata to close, limiting the water loss from transpiration • 4. Transpiration and Wilting - osmotic pressure keeps a plant’s leaves and stem rigid. High transpiration rates can lead to wilting - the plant’s cells lose pressure causing the cell walls to bend inward. When a leaf wilt the stomata close to further conserve water.

  21. Transpiration Section 23-5 A B Evaporation of water molecules out of leaves. Pull of water molecules upward from the roots.

  22. Transpiration Section 23-5 A B Evaporation of water molecules out of leaves. Pull of water molecules upward from the roots.

  23. Figure 23–24 Phloem Transport Section 23-5 Phloem Xylem Sugarmolecules Source cell Movementof water Movementof sugar Sink cell

  24. Video Contents Videos • Click a hyperlink to choose a video. • Water Transport in Plants • Sugar Movement in Plants

  25. Video 1 Video 1 • Click the image to play the video segment. Water Transport in Plants

  26. Video 2 Video 2 Sugar Movement in Plants • Click the image to play the video segment.

  27. Internet Go Online • Share root growth lab data • Interactive test • Articles on plants • For links on plant anatomy, go to www.SciLinks.org and enter the Web Code as follows: cbn-7231. • For links on root structures, go to www.SciLinks.org and enter the Web Code as follows: cbn-7232. • For links on leaf functions, go to www.SciLinks.org and enter the Web Code as follows: cbn-7234.

  28. Section 1 Answers Interest Grabber Answers 1. What plant characteristics must you consider in your design? Possible student answers: cell wall, cell membrane, and cell vacuole, and the presence of cellulose, especially as they relate to osmosis, diffusion, and turgidity. 2. What environmental conditions must you take into account for your design to be functional? Possible student answers: availability of water, temperature, pressure, sunlight, and gravity. 3. Outline the major characteristics of your design. Student designs will vary, but should take into consideration the characteristics listed in questions 1 and 2.

  29. Section 2 Answers Interest Grabber Answers 1. The love of money is the root of all evil. The core, origin, or beginning; the root is the core of the plant that grows from it. 2. Tired of moving from place to place, he took root in our hometown. Become settled or secure; plant roots secure plants in the ground 3. The police were determined to root out the criminals. Remove, pull out; plants must be pulled out by the roots, which secure them to the ground.

  30. Section 3 Answers Interest Grabber Answers 1. How do the stems of trees, flowering plants, and cacti differ? They differ in shape and size. 2. How are the stems of these plants similar? They all support the plants and transport nutrients.

  31. Section 4 Answers Interest Grabber Answers 1. Describe the shape of each leaf. Broad and flat with pointed ends (oak); long and flat with wavy edges (dandelion); long and needle-shaped (pine) 2. Describe the features of each leaf. They are green in color and have surfaces that are shiny and waxy, stems, and veins separated by flat areas. 3. How is the structure of a leaf related to its function? The flat areas collect sunlight, the veins transport nutrients, and the green color (chlorophyll) traps energy from the sun.

  32. Section 5 Answers Interest Grabber Answers 1. When the end of a narrow tube is placed in water, the water rises in the tube to a level that is higher than the water outside the tube. Which force causes this to occur? Cohesion between the water and the tube 2. How might this force cause water to rise in the stem of a plant? Cohesion between the water and the vascular tissue of the plant could cause water to move upward. 3. When water molecules evaporate from the surface of a leaf, how do the forces of adhesion and cohesion resist this action? Adhesion between water molecules could hold the escaping molecules in the plant. Cohesion between the plant tissues and the escaping water molecules might oppose evaporation. 4. When water molecules evaporate from the surface of a leaf, which force would cause other water molecules to move upward in the plant and follow the evaporating water? Adhesion between water molecules could cause evaporating water molecules to pull more water molecules along behind them.

  33. End of Custom Shows • This slide is intentionally blank.

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