Growth in Plants

1. Growth is an irreversible increase in size. In plants, this is a function of cell division coupled with cell elongation Growth in Plants Primary growth elongates the axis of a plant Secondary growth increases the girth of a plant

2. Meristems Cell division in plants is restricted to regions of parenchyma called meristems.

3. There are three types of meristems.

4. Apical Meristems These extend the length of the shoot or root.

5. Lateral Meristems These extend the girdth of a stem or root.

6. Intercalary Meristems These are regions of growth situated between two regions of mature (non-growing) tissue Why grass grows upward after it is mowed. This is all we will say about intercalary meristems……. intercalary meristem

7. Apical meristems extend the length of the plant body

9. Lateral Meristems Increase the Girth of the Plant Body

11. Primary Tissuesresult from primary growth which are derived from apical meristems.

12. Primary Plant Growth and Development

13. In mature tissues, cells are arrested in interphase

14. Primary growth is a product of Cell division

16. Primary growth is a product of Cell division Cell elongation

18. Primary growth is a product of Cell division Cell elongation Ending with cell/tissue differentiation-maturation

20. In primary growth, cell division isn’t entirely restricted to the apical meristem proper. Cell division continues in the derived immature tissues behind the apical meristem. These tissues are called the primary meristematic tissues. Protoderm matures to form the epidermis Ground Meristem matures to form the ground tissue Procambium matures to form the vascular tissue

21. Undifferentiated Cells of Apical Meristem Procambium Protoderm Ground Meristem Ground Tissue Vascular Tissue Epidermis

22. Primary growth in the root Simpler than in the shoot as there are no nodes or internodes Always includes a root cap. The apical meristem of the root encompasses some of the area of the root cap

23. Apical Meristem of the Root

24. Regions of growth of a root tip Region of cell division Region of cell elongation Region of maturation

25. Region of celldivision

26. Region of elongation

27. Region of Maturation

28. Regions maturation elongation division

29. Regions

31. Primary Meristematic Meristems in a Root Tip Protoderm = outer layer of cells Procambium = inner core of cells Ground Meristem = everything else

32. Protoderm Protoderm

33. Procambium Procambium

34. Ground Meristem Ground Meristem

35. Primary Growth in the Shoot Is more complex because it generates both leaf and stem tissue along with the axillary buds at the internodes.

36. Gross Morphology Apical Meristem of the Shoot

37. Apical meristems of the Shoot are more complex than that of the root.

38. Leaf Primordium

39. Three primary meristmatic tissues Protoderm

40. Procambium

41. Ground Meristem

42. Gross Morphology Vascular Strands

43. Gross Morphology Leaf Traces

44. Gross Morphology Leaf Gaps

45. Secondary Tissues are Derived from Lateral Meristems Called Cambia

46. Except for the pith and some primary xylem bordering the pith, this is all secondary tissue

47. Secondary growth produces vascular tissue and dermal tissue, but not ground tissue.

48. The Vascular Cambium Produces Xylem to the Inside and Phloem to the Outside

49. The Cork Cambium Produces Dermal Tissue (cork) to the Outside