1. BOT3015L Biology of Flowering Plants Anatomy Seedlings, Meristems, Stems, and Roots Presentation created by Danielle Sherdan All photos from Raven et al. Biology of Plants except when otherwise noted

2. Today Review seeds and the life cycle of plants Seed germination Roots and root meristem The three primary tissues Specialized cells in primary root tissues Interesting examples of root function and adaptations Shoot and shoot meristem Review seeds and the life cycle of plants Seed germination Roots and root meristem The three primary tissues Specialized cells in primary root tissues Interesting examples of root function and adaptations Shoot and shoot meristem

3. Life cycles From Outlaw’s lecture series

4. Angiosperm life cycle From Outlaw’s lecture series Floral structure Gametophytes Today

5. Monocot seed development typical monocot (maize) seed with ovary wall (pericarp) Monocots have one cotyledon (scutellum in grasses) that matures during germination Source of nutrition for seed germination: endosperm (compare to dicot) Maize fruit and seed

6. Dicot seed development mature dicot - two cotyledons immature Three tissue systems: Dermal Vascular Cortex or Ground All cells of the primary growth in dicots are part of these three systems and originate at meristems... A reminder that endosperm is formed in all angiosperms, but does not persist in dicots. In dicots, cotyledons are the primary source of nutrients for germination.

7. Today Review seeds and the life cycle of plants Seed germination Roots and root meristem The three primary tissues Specialized cells in primary root tissues Interesting examples of root function and adaptations Shoot and root meristem

8. Seed germination What causes a seed to resume growth? What observations did you make while germinating seeds? What is growth? Plants-In-Motion Time-lapse videos of plant growth and response Broadly, where do the energy and basic elements required for growth come from?

9. Dicot germination and seedling An example of epigeous (epi=above, geo=earth) germination

10. Dicot germination and seedling An example of hypogeous (hypo=below, geo=earth) germination

11. Monocot germination and seedling

12. Today Review seeds and the life cycle of plants Seed germination Roots and root meristem The three primary tissues Specialized cells in primary root tissues Interesting examples of root function and adaptations Shoot and shoot meristem

13. Root the first structure to emerge from the germinating seed Typical dicot Taproot persists and grows deep into the ground Typical monocot Taproot does not persist and adventitious roots originate from the shoot Notice the high surface volume: area ratio

14. Typical of a dicot Typical of a monocot Tap Root vs. Fibrous Root From Outlaw lecture What are the functions of roots?

15. Organization of the plant body Apical = at the tip (of the root, the shoot, including laterals) Meristem = group of perpetually “embryonic” cells Root apical meristem

16. The rootcap and mucigel protect the root apical meristem as it pushes through the soil Mucigel

17. Today Review seeds and the life cycle of plants Seed germination Roots and root meristem The three primary tissues Specialized cells in primary root tissues Interesting examples of root function and adaptations Shoot and shoot meristem

18. All cells of primary growth are from one of three primary tissues

19. Diagram of major parts of primary dicot plant body Ground tissue is throughout the plant body

20. Ground tissue of typical dicot root and shoot Root Buttercup (Ranunculus) Shoot Alfalfa (Medicago)

21. All cells are from one of three primary tissues

22. Diagram of major parts of primary dicot plant body Vascular tissue is throughout the plant body

23. Vascular tissue of typical dicot root Root Buttercup (Ranunculus)

24. Vascular tissue of typical dicot shoot Shoot Alfalfa (Medicago)

25. All cells of primary growth are from one of three primary tissues

26. Diagram of major parts of primary dicot plant body Dermal tissue is throughout the plant body

27. Ground tissue of typical dicot root and shoot Root Buttercup (Ranunculus) Shoot Alfalfa (Medicago)

28. Specialized dermal cells in the shoot The structure of the leaf and aspects of stomatal physiology will be topics of study next week

29. Specialized epidermal cells Venus flytrap

30. Today Review seeds and the life cycle of plants Seed germination Roots and root meristem The three primary tissues Specialized cells in primary root tissues Interesting examples of root function and adaptations Shoot and shoot meristem

31. Root Hairs—a special feature of roots (a) Radish (Raphanus) Bentgrass (Agrostis)

32. Root Hairs—a special feature of roots (b) Cell Division Cell Elongation

33. Root Hairs—a special feature of roots (c) More than with shoots, elongation growth is restricted to very near (~1.5 mm) the root tip; otherwise, elongation would tear off lateral appendages. Root hairs increase surface area.

34. Typical dicot root Root Buttercup (Ranunculus)

35. The endodermis Casparian Strip—a band of hydrophobic material (mostly suberin) that is impregnated in the wall, preventing apoplastic transport. From Outlaw’s lecture

36. The endodermis Pathways for entry into xylem transport: all require that the solute be transported into the symplast (because the apoplast is discontinuous at the endodermis). Then, solutes are excreted into the apoplast interior to the endodermis. Apoplast Symplast From Outlaw’s lecture

37. Typical dicot root Root Buttercup (Ranunculus)

38. Secondary Growth (root) Example cross section of the dicot root in primary growth The cambium (perpetually meristematic layer between xylem and phloem) divides mitotically, producing either: A secondary xylem cell to the inside and a replacement cambial cell. OR A secondary phloem cell to the outside and a replacement cambial cell. Secondary growth rare in monocots From Outlaw’s lecture

39. Ordinarily, lateral roots arise in the pericycle. But roots can arise adventitiously, too. (Adventitious simply means arising in an unusual location.) The pericycle Salix (Salicaceae family) From Outlaw’s lecture

40. Today Review seeds and the life cycle of plants Seed germination Roots and root meristem The three primary tissues Specialized cells in primary root tissues Interesting examples of root function and adaptations Shoot and shoot meristem

41. Support roots in the marsh habitat. Mangrove (a dicot) Interesting Examples From Outlaw’s lecture

42. Aerial roots absorb water from the air and have a multi-layered epidermis for protection and reduced water loss Orchid (a monocot) Interesting Examples Epidermal layers Cross section of root

43. Modified leaves form hollow containers that roots grow into and that collect rainwater and debris. Many ants associate with these plants, likely adding to nitrogen supply Flower pot plant (an epiphyte) Interesting Examples

44. Today Review seeds and the life cycle of plants Seed germination Roots and root meristem The three primary tissues Specialized cells in primary root tissues Interesting examples of root function and adaptations Shoot and shoot meristem

45. The shoot What are the functions of the shoot?

46. Primary tissues differently organized in angiosperm shoots Typical of dicots Typical of monocots

47. Example dicot stem cross section vascular bundles in ring with defined pith and cortex Primary tissues differently organized in angiosperm shoots Shoot Alfalfa (Medicago)

48. Example monocot stem cross section vascular bundles scattered Primary tissues differently organized in angiosperm shoots Maize (Zea)

49. Apical Meristems both have the three primary tissues ShootRoot Lilac (Syringa) Radish (Rafarus)

50. Block Diagram of Typical Shoot Apical Meristem Primary meristems give rise to primary tissues Modified from Outlaw’s lecture Lilac (Syringa)

51. Example cross section of the dicot shoot in primary growth Secondary Growth (shoot) The cambium (perpetually meristematic layer between xylem and phloem) divides mitotically, producing either: A secondary xylem cell to the inside and a replacement cambial cell. OR A secondary phloem cell to the outside and a replacement cambial cell. From Outlaw’s lecture

52. The main idea