This is about study of internal structure of plants , which is anatomy.

1. Chapter 6
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

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

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

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

28. Specialized dermal cells in the shoot
- a preview of next week’s topics
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
Three 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
Shoot
Root
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

53. Important Announcement/Reminder
Review photosynthetic electron
transport and photosynthetic carbon
metabolism from BSC 2010.
Instead of reviewing your 2010 notes/text, you may refer to Outlaw’s
website:
http://bio.fsu.edu/~outlaw/courses/BSC_3402L/
And select Scientific Background.