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ROOTS AND STEMS - BOTANY LAB SEMI FINALS

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ROOTS AND STEMS - BOTANY LAB SEMI FINALS

  1. 1. Roots Plant organ systems
  2. 2. What are the primary functions of roots?
  3. 3. Fibrous and taproot systems
  4. 4. Dicots Monocots
  5. 5. Root structure
  6. 6. Root cap • Parenchyma • Perception of gravity
  7. 7. Zone of Maturation - cell differentiation Protoderm Ground Meristem Provascular Zone of Cell Elongation - cell expansion Notice how the growing zone has no root hairs or lateral roots! Growth among soil particles would result in shear forces. Zone of Cell Division - new cells by mitosis Root Cap - penetration, padding
  8. 8. Mucilage Slough Cells
  9. 9. Gravitropism Root Tip Senses Gravity Auxin Hormone Produced Auxin Accumulates on Lower Growth Inhibited on Lower… Relative to Upper Root Curves Downward Water and Mineral Uptake Root Hairs Increase Surface Area Root Hairs Secrete Acid (H+) H+ Cation Exchange w/Minerals Mineral Uptake into Roots
  10. 10. Region of maturation
  11. 11. Mature root structure
  12. 12. Monocot root, c.s.
  13. 13. Dicot root, c.s.
  14. 14. Xylem Phloem Endodermis
  15. 15. Endodermis regulates mineral absorption
  16. 16. Lateral (branch) roots
  17. 17. Endodermis Pericycle
  18. 18. Endodermis Pericycle
  19. 19. Specialized roots • Storage roots
  20. 20. Propagative roots
  21. 21. Pneumatophores
  22. 22. Aerial roots
  23. 23. Aerial roots – velamen (orchids)
  24. 24. Contractile roots
  25. 25. Prop roots
  26. 26. Root nodules
  27. 27. Root nodules
  28. 28. Parasitic roots • Witchweed
  29. 29. •Support •Conduction •Growth Stem functions
  30. 30. Vascular bundle arrangement of roots and stems Roots Stems Monocot Dicot
  31. 31. Dicot stem anatomy
  32. 32. Coleus stem vascular bundles
  33. 33. Dicot stem anatomy
  34. 34. Secondary growth of dicot stems
  35. 35. heartwood sapwood
  36. 36. secondary xylem secondary phloem
  37. 37. Annual rings of phloem phloem fibers
  38. 38. Lenticels Lenticels
  39. 39. Lenticels
  40. 40. Specialized stems
  41. 41. Cladophyll
  42. 42. Thorns
  43. 43. Tendrils
  44. 44. That’s a big stem! • Baobab (Adonsonia digitata) grow up to 45 ft. in diameter
  45. 45. That’s a big stem! Redwoods grow up to 350 ft tall; 30 ft. dia.
  46. 46. Bristlecone pines • Oldest organism – 4767 yrs. old

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