1. Plant Structure and Growth

2. Three main organs: Roots Stems Leaves

3. Plant Structure and Growth Three main organs: Roots Stems Leaves (Angiosperms have a fourth main organ—the flower.)

4. Plant Structure and Growth Monocots One cotyledon Parallel veins Complex vascular bundles Fibrous roots Petals x 3. Dicots Two cotyledons Net-like veins Vascular bundles in rings Tap roots Petals x 4 or 5. Two types of angiosperms:

5. Plant Structure and Growth Roots Fibrous roots absorb water well Tap roots hold fast in the ground and store nutrients All roots absorb water mostly at the root tips, through root hairs Adventitious roots prop up tall stems.

6. Plant Structure and Growth Stems Nodes and internodes Axillary bud by each leaf

7. Plant Structure and Growth Stems Nodes and internodes Axillary bud by each leaf Terminal bud at the apex Apical dominance Stolons are “runners.”

8. Plant Structure and Growth Leaves Main photosynthetic organ Blade and petiole (stalk) Simple, compound, double compound.

9. Plant Structure and Growth Three main tissue systems: Dermal Vascular (xylem and phloem) Ground.

10. Plant Structure and Growth Dermal Tissue Single layer of cells over the outside Secretes waxy cuticle

11. Plant Structure and Growth Vascular tissue Xylem carries water up Phloem carries food down Tracheids and vessel elements in the xylem are dead at functional maturity Sieve tube members and companion cells in the phloem are alive.

12. Plant Structure and Growth Ground tissue Includes pith and cortex

13. Plant Structure and Growth Types of plant cells: Parenchyma (unspecialized) Collenchyma (support growing parts of plant) Sclerenchyma (support mature parts of plant) Tracheids (xylem, dead at maturity) Sieve-tube members (phloem.)

14. Plant Structure and Growth Meristems generate cells for new organs Apical meristems elongate roots and shoots. Lateral meristems add girth to woody plants.

15. Plant Structure and Growth Bark includes phloem and periderm. Periderm includes cork cells, which form a waxy protective substance.

16. Plant Structure and Growth Morphogenesis in plants

17. Plant Structure and Growth The Plane and Symmetry of Cell Division

18. Plant Structure and Growth The Plane and Symmetry of Cell Division A band of microtubules called the preprophase band (PPB) determines the plane of cell division

19. Plant Structure and Growth The Plane and Symmetry of Cell Division A band of microtubules called the preprophase band (PPB) determines the plane of cell division

20. Plant Structure and Growth The Plane and Symmetry of Cell Division A band of microtubules called the preprophase band (PPB) determines the plane of cell division.

21. Plant Structure and Growth The Plane and Symmetry of Cell Division The fas mutant has disorganized microtubules and grows into a disorganized plant.

22. Plant Structure and Growth The Plane and Symmetry of Cell Division The fas mutant has disorganized microtubules and grows into a disorganized plant.

23. Plant Structure and Growth Orientation of Cell Expansion

24. Plant Structure and Growth Orientation of Cell Expansion Microfibrils control the direction of cell expansion

25. Plant Structure and Growth Orientation of Cell Expansion Microfibrils control the direction of cell expansion.

26. Plant Structure and Growth Orientation of Cell Expansion Plants can expand very quickly because much of the increase in cell volume is just water in the central vacuole.

27. Plant Structure and Growth Morphogenesis and Pattern Formation Remember the homeotic genes that we learned about in animals?

28. Plant Structure and Growth Morphogenesis and Pattern Formation Remember the homeotic genes that we learned about in animals? Plants have them too.

29. Plant Structure and Growth Morphogenesis and Pattern Formation Cells need positional information.

30. Plant Structure and Growth Morphogenesis and Pattern Formation Cells need positional information. Auxin, a hormone secreted at the tip of the plant, is in less and less concentration the further down you go.

31. Plant Structure and Growth Morphogenesis and Pattern Formation Cells need positional information. This establishes the root end and the shoot end, and lets the cell know how far down it is.

32. Plant Structure and Growth Morphogenesis and Pattern Formation Cells need positional information. Another hormone secreted at the surface of the stem is in less concentration the further it you go. This tells the cell how far inside it is.

33. Plant Structure and Growth Morphogenesis and Pattern Formation Morphogenesis is controlled by homeotic genes

34. Plant Structure and Growth Morphogenesis and Pattern Formation Morphogenesis is controlled by homeotic genes Mutations in the homeotic genes can cause “supercompound” leaves.

35. Plant Structure and Growth Plants also undergo phase changes Juvenile growth to mature growth Vegetative growth to reproductive growth (flower formation).

36. Parts of a Flower Plant Structure and Growth

37. ovule Parts of a Flower Plant Structure and Growth

38. ovary ovule Parts of a Flower Plant Structure and Growth

39. style ovary ovule Parts of a Flower Plant Structure and Growth

40. stigma style ovary ovule Parts of a Flower Plant Structure and Growth

41. stigma style carpel ovary ovule Parts of a Flower Plant Structure and Growth

42. anthers Parts of a Flower Plant Structure and Growth

43. anthers filaments Parts of a Flower Plant Structure and Growth

44. anthers stamens filaments Parts of a Flower Plant Structure and Growth

45. petals Parts of a Flower Plant Structure and Growth

46. petals Parts of a Flower Plant Structure and Growth

47. petals sepals Parts of a Flower Plant Structure and Growth

48. Parts of a Flower Plant Structure and Growth

49. Seen from above, these structures are in four concentric rings or “whorls.” Plant Structure and Growth Sepals Petals Stamens Carpals

50. Their development is controlled by three homeotic genes called A, B, and C. Plant Structure and Growth Sepals Petals Stamens Carpals

51. Their development is controlled by three homeotic genes called A, B, and C. Plant Structure and Growth Sepals Petals Stamens Carpals A C B

52. Wild type flower CCCBBCABABAA

53. Mutant lacking A CCCBBC CCBC

54. Mutant lacking B CCCCAAAA

55. Mutant lacking C AABAAB ABAA