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Vascular Tissue- Chapter 20

Vascular Tissue- Chapter 20. Concept 20.2. Root System Anchor & Support Absorb minerals and water Monocot root- fibrous-mat -grass Dicot root-tap root-1 vertical root-carrot Shoot System Stems, leaves, flowers Support Transport-transport tissue. Plant Root and Shoot System.

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Vascular Tissue- Chapter 20

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  1. Vascular Tissue- Chapter 20

  2. Concept 20.2 • Root System • Anchor & Support • Absorb minerals and water • Monocot root- fibrous-mat -grass • Dicot root-tap root-1 vertical root-carrot • Shoot System • Stems, leaves, flowers • Support • Transport-transport tissue

  3. Plant Root and Shoot System • Shoot System= stems, leaves, flowers • Undeveloped shoots are buds. • Terminal buds- stem tip • Axillary- in the axils (angles) between leaf and main stem. Growth from here produces plant branches. • Blade- main part of the leaf. • Petiole- stalk connecting the leaf to the stem. • Veins- carry water and nutrients-vascular tissue and support tissue. • Examples of modified leaves- • Celery stalks- petioles; spines on cactus, tendrils • Grass-no petioles.

  4. Plant tissue system-3 types • Dermal Outer covering- “skin”- epidermis Protects • Vascular Tissue- 2 types • Transport • Xylem- water and minerals from roots-shoots • Phloem-food from leaves down. • Roots-in center • Stems- in vascular bundles. • Monocot vs dicot differences

  5. Monocot vs Dicot Root

  6. Monocot vs Dicot stems

  7. 3. Ground Tissue- mostly parenchyma cells • Fills in between the dermal and vascular tissues. • Functions in photosynthesis, storage, and support in young shoots. Plant Tissue- • Is made up of more than 1 type of plant cell. Different cell types- • Parenchyma- thin c. wall & large vacuoles. • Most abundant in fruit. Makes up phloem. • Collenchyma- thick, uneven; provides support; elongates. • Sclerenchyma- support; forms skeleton; makes up the water-conducting cells of xylem.

  8. Primary Growth- Concept 20.3 • Plants grow throughout their lifetime. • Meristematic Tissue- differentiates into the 3 main tissues- dermal, vascular, ground. • Apical meristems- found tips of roots and shoots. • Primary Growth- growth in length • roots- below ground • shoots- above the ground

  9. Primary Growth in Roots and Shoots

  10. Primary Growth- growth in length • Figure 20-13 – • Root cap-protects delicate cells of apical meristem. • Primary growth -3 cylinders of developing tissues • Outermost cylinder- dermal tissue • Middle- cortex • Inner cylinder- vascular tissue • Xylem • Phloem

  11. Concept 20.4- Secondary Growth • Woody plants – vines, shrubs, trees • Growth in plant thickness- width • Cell division in 2 meristematic tissues: vascular cambium and cork cambium

  12. Vascular cambium- • A cylinder of actively dividing cells • Between the xylem and phloem • Adds cells both sides • Secondary xylem inside • Secondary phloem outside • Secondary xylem-wood. • Growing season • Dormant in winter • Stem / root thickens with each new xylem • Sapwood- new xylem actively transporting water • Heartwood- old xylem not transporting water • Secondary phloem- outside vascular cambium.

  13. Cork cambium- • meristem- produces cork • When cork cells die-thick waxy walls-prevent water loss • Barrier of protection • Bark- everything to the outside of the vascular cambium- • Includes phloem, cork cambium, and cork

  14. Secondary Growth

  15. Tree rings • Age from annual rings = year of growth • Easiest to count dark bands of secondary phloem from outside to inside. • Environmental conditions- differences in ring width. • Each ring- • Spring- cool, plenty of water conditions • Produce large, thin walled cells of xylem • carry lots of water. • Summer- hot, dry conditions • Narrow thick walled cells

  16. Tree Rings- History of the Plant

  17. What nutrients do plants need?Concept 21.1 • Plant get nutrients from _____ and _____. • Air supplies carbon dioxide and ________. • Water supplies hydrogen and serves as a solvent for dissolved minerals. • Plants have simpler needs than animals • Plants require 17 chemical elements for their life cycles

  18. Chemical elements needed/function • Nitrogen- proteins and nucleic acids • Sulfur- proteins • Phosphorous- nucleic acid and ATP • Potassium – protein synthesis and osmosis • Na+-K+ pump • Calcium-cell wall, enzyme activity • Magnesium- chlorophyll synthesis, enzyme activity

  19. Consequences of poor nutrition • Growth –stunted • No flowers produced • Stems, roots, leaves may die • Yellow leaves if no chlorophyll produced

  20. Vascular transport Concept 21.2 • Roots –absorb water and minerals • Root hairs & Mycorrhizae • Xylem- moves water and minerals upward • 2 forces- 1. Root pressure- • Pushes water up the xylem (at night) • Root epidermal and ground tissue cells use ATP to get minerals – into xylem • Endodermis around vascular tissue-waxy cells- prevents leakage of water. • Water enters xylem by osmosis

  21. 2. Transpiration-pull- • Main force- pulls xylem up • Transpiration- loss of water thru leaves due to evaporation. • Cohesion : same kind molecules stick together • water –water • Adhesion : attraction between unlike molecules ( • water – cellulose (xylem walls)

  22. Regulating water loss • Stomata (singular-stoma) • Pores on underside epidermis of leaf • gas exchange – CO2 • Guard cells- • surround stoma- • open and close stoma by changing shape • Open- day- to let in CO2 • Closed- night- to prevent water loss. • Leaf Diagram- Structure

  23. Water follows potassium ionsfrom surrounding cells into guard cells.

  24. Leaf Structure

  25. Leaf Cross-section

  26. Flow of Phloem • Phloem- “food phloem down” • Transports sugar and organic compounds + water. • From source (mature leaves-photosynthesis) to sink(where needed- roots, fruits, developing shoots). • Pressure-flow mechanism- • Water follows sugar; high conc. to low conc.

  27. Sieve tubes carry phloem sapPressure-Flow mechanism- hypothesis for movement of phloem sap.

  28. 21.3 Carnivorous Plants Some plants – N from animals Ex: sundews, Venus's flytraps, pitcher plants Little organic N where they live (wetlands, cold, acidic water, decay slow) Still photosynthesize

  29. Ch. 22.1 Plant hormones –chemical messengers Control: Germination Growth Flowering Fruit production

  30. 1. Auxins Apical meristems – shoot tips Cell elongation Secondary growth – vascular cambium Seeds – auxin – signal ovary to fruit Auxins - no pollination  seedless fruit

  31. Phototropism • Auxin builds – shaded side • Shaded cells lengthen more, more water • Uneven sides = bending

  32. 2. Cytokinins • Cell division – made in roots • Cytokinin with auxin • Fewer / shorter branches near tip 3. Gibberellins • Fruit – seedless, larger

  33. 4. Abscisic Acid (ABA) • Limits cell division • Stops growth • Dormancy • “stress hormone” 5. Ethylene • Fruit ripening • “leaf drop”

  34. 22.2 Plant Responses Rapid plant movements Touch Rapidly reversible Tropisms – slowly grow toward or away from a stimulus Slow to reverse

  35. 1. Thigmotropism • Touch • Climbing plants – tendrils • Seedling - obstacle 2. Phototropism • Light • Uneven auxins – light one side 3. Gravitropism • Gravity • Seedling root / shoot

  36. Disease • Viruses, bacteria, fungi • Adaptations • Epidermis • Chemicals – lignin • Resistant genes • Thorns, poisons

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