1. Anatomy & Growth of Angiosperms

2. Two plant groups: monocots & eudicots

3. I. Introduction A. Uniqueness of Plants

4. B. Forces for Change 1. Genetics 2. Environment – two time scales:
a. Long-term: accumulation of adaptations that
enhanced survival & reproduction (evolution by
natural selection)
b. Short-term: plasticity = wide range of
phenotypes for each genotype. Allows plants to
adjust to changing environment (ex. Shorter plant in
dry year so that it can still reproduce)

5. Muscle cell
Muscle tissue
Heart
Circulatory system
Parenchyma cell
Dermal tissue
Leaves
Shoot system
Cells
Tissues
Organs
Systems

6. II. Plant Organs: Roots, Stems, Leaves
A. Roots
1. Functions
a. Collect water & minerals from soil
b. Anchor plant
c. Store food (carb’s from photosynthesis) to
be used for flowering & fruiting
d. Covered with root hairs – increases surface
area for absorption

7. Fig. 35.2

8. 2. Types a. Prop root c. Aerial strangler root b. Storage root
Fig. 35.4
a. Prop root
c. Aerial strangler root
b. Storage root
d. Buttress root
e. Pneumatophore

9. B. Stems/shoots 1. Functions a. Support, transport
b. Some photosynthesis
2. Two types of shoots
a. Vegetative – leaves only
b. Reproductive – produces flowers

11. 3. Two parts of the stem:
a. Node – point of leaf attachment
b. Inter-node – stem segments between nodes

13. 4. Buds
Apical dominance = the presence of an apical bud inhibits the growth of axillary buds.
- remove or depress apical bud, axillary buds begin to grow.
a. Terminal bud – contains a shoot apical
meristem; shoot growth is concentrated here
b. Axillary buds – in angle (axil) between leaf &
branch, contain meristem with potential to become a
vegetative shoot. Mostly dormant.

14. Fig. 35.2

15. 5. Modified Shoots (stems):
a. Stolons – above-ground runners
b. Rhizomes – below-ground runners
Asexual, vegetative propagation
c. Bulbs – swollen underground shoots
d. Tubers – swollen rhizomes
Stores food for later growth

16. Fig. 35.5

17. C. Leaves – main photosynthetic organs
1. Parts
a. Petiole
b. Blade

18. 2. Types
Compound, doubly compound – why??

19. a. Tendrils
Fig. 35.7
3. Modified leaves
b. Spines
c. Succulents

20. III. Plant Tissue
Fig. 35.8

21. A. Dermal or Epidermis 1. Characteristics
a. single layer of tightly packed cells covering
the young parts of the plant.
b. Functions in protection
c. Root hairs are specialized epidermal
extensions
d. Secretes waxy cuticle of the leaf

23. a. Fills the space between dermal and vascular tissue systems.
B. Ground
1. Characteristics
a. Fills the space between dermal and
vascular tissue systems.
b . Diverse functions:
Photosynthesis, storage, & support
pith
In eudicots stems:
cortex

24. C. Vascular 1. Characteristics
a. function in transport between roots & shoots,
and structural support of plant
2. Types
a. Xylem: H2O & minerals transported up to
shoot system
b. Phloem: Food transported to roots & non-
photosynthetic parts such as the flowers

25. IV. The Plant Cell
Fig. 7.8

26. A. Generalized Same as animals, except:
1. No lysozomes (digestive organelle)
2. Cell walls: maintains shape, structural support,
protects from damage. Made of cellulose, protein, &
sometimes lignin
3. Chloroplasts
4. Vacuole – storage, waste breakdown, growth!
5. Plasmodesmata – holes in cell wall, creates
channels to connect cytoplasm of adjacent cells

27. B. Plant Cell Categories
1. Parenchyma
4. Water-conducting cells of the xylem
3. Sclerenchyma
5. Sugar-conducting cells of the phloem
2. Collenchyma

28. 1. Parenchyma a. Characteristics
i. Least specialized cell. Can differentiate into
other cell types
ii. Primary cell walls only - thin and flexible
iii. Lack secondary plant cell walls
iv. Most metabolically active – lots of chloroplasts
for PSN (PhotoSyNthesis)
v. Starch, carbohydrate production & storage in
stems

29. 2. Collenchyma a. Characteristics
i. Primary walls are unevenly thickened
ii. Usually lack secondary walls.
iii. Usually grouped in strands to support young
parts of plants without restraining growth
iv. Flexible, elongate with growing shoots

30. 3. Sclerenchyma a. Characteristics i. Function in mechanical support
ii. Have rigid and thick secondary walls
strengthened with lignin.
iii. May be dead at functional maturity
iv. Cell walls left behind as skeleton

31. Lignin:

32. 3. Sclerenchyma b. Two types, both function in support:
i. Fibers - long, slender, tapered cells occurring in
bundles.
ii. Sclereids - short, irregularly-shaped. Ex. hard seed coats

34. Fig.35.9

35. 4. Water/Mineral conducting cells of the xylem:
a. 2 types: tracheids & vessel elements

36. i. Tracheids
are long, thin tapered cells having lignin-hardened
secondary walls with pits.
Dead at maturity
Water flows from cell to cell (laterally) through pits
in cell wall (1o wall only)
Support function
ii. Vessel Elements
are wider, shorter
Arranged end-to-end to form tubes
End walls are perforated for free flow of water
More efficient as water conductors than tracheids

37. Fig. 35.9

38. 5. Sugar-conducting cells of the phloem
a. 2 types
i. Sieve-tube members:
Chains of cells arranged end-to-end, Alive at functional
maturity, Lack a nucleus, ribosomes, & vacuole, and
Cells separated by perforated sieve plates – allow sugar
movement.
ii. Companion cells:
Load sugars into the sieve tube member, Nucleus and
ribosomes also serve the sieve-tube member.

39. Fig. 35.9

40. V. Growth & Development

41. A. Definitions
1. Development is the sum of all the changes
2. Cell Division
3. Morphogenesis

42. B. Processes of plant cellular development:
1. Cell Growth
a. Cell division (Mitosis) in itself does not mean an
increase in growth.
b. Cell division yields no expansion of size.
c. Cell elongation increases growth.

43. Fig

44. 2. Cell elongation a. due to water uptake
b. Direction of expansion = perpendicular to
alignment of cellulose microfibrils in cell wall
c. Enzymes weaken cross-link between microfibrils,
allowing cell to expand.

45. Fig

46. Fig. 39.8

47. 3. Morphogenesis
a. The coordinated arrangement of cells into tissues & organs
b. Pattern formation – development of specific structures in
specific places (e.g. Flowers born on the terminus of branches as
opposed to leaf axils.
c. Depends on:
i. Positional information – chemical signals from surrounding
cells indicate the cell’s position on plant
ii. Polarity of the plant, asymmetrical cell divisions
iii. Both affect the transcription of homeotic genes

48. 4. Cellular Differentiation
a. Transformation of genetically identical cells into cells with
diverse biochemical and structural features. How?
i. Selective transcription of appropriate genes
ii. How? Chapters 18 & 39
iii. Flow of Info

49. The Flow of Information
Transcription
Replication
Translation
Modification
RNA
Polypeptide
Functional Protein
DNA
Energy
Amino Acids
Additional Materials

50. b. Regulation i. at transcriptional level
ii. Regulation at translational level
iii. Regulation at post translational level
iv. Hormonal controls
v. Regulation at substrate level
vi. Regulation by environmental signals: light,
gravity,…..

51. c. Processes
i. Meristem identity genes – cause a vegetative shoot to become a
floral shoot
ii. Positional information (derived from chemical messengers)
selectively turn on or off organ–identity genes.
iii. Organ – identity genes - code for transcriptions factors that
regulate expression of genes controlling the development of specific
organs.

52. By “turning off” organ identity genes, we can give a rose more petals
Fig
By “turning off” organ identity genes, we can give a rose more petals

53. C. Plant growth vs. Animal growth
1. Comparison:
a. Embryonic, developing, and mature organs exist together
at the same time on one plant.
b. Grow until they die, called indeterminate growth. Some
determinate parts: leaves, flowers.

54. D. Plant life cycles:
1. Annual – complete life cycle (germination through
fruiting) in one year or less. Examples: grasses, crops,
wildflowers
2. Biennial – complete life cycle in two years (first year
= vegetative, second year = reproductive). Some need a
cold winter period to initiate flowering from vegetative
state. Ex. carrots
3. Perennial – live year after year, do not die after
reproduction. Examples: trees, shrubs, some grasses.
Causes of death = fire, disease

55. E. Plant Growth Sites Meristems
Meristems are regions of the plant with continuous cell
division (i.e. perpetually embryonic tissue)
1. Types of meristems:
a. Apical meristem – located at the root and shoot tips,
responsible for growth in length (called primary growth)
b. Lateral meristems – extend lengthwise along the axis of the
stem & roots. Responsible for growth in girth in older parts of
the plant (called secondary growth). Exist only in perennials
How is indeterminate growth possible?????

56. Fig

57. 2. Primary Growth of Roots
a. Description
i. Occurs at root tip (Root Apical Meristem)
ii. Root cap – layer of cells that protect the RAM as it pushes
through the soil

58. b. Zones i. Zone of cell division – contains the RAM
ii. Zone of cell elongation – cells elongate, thereby pushing
the root tip through the soil
iii. Zone of maturation – cells differentiate and become
functionally mature (i.e. become part of one of the 3 tissue
systems)

59. Fig

60. 3. Shoots a. Leaves arise on sides of the Shoot Apical Meristem (SAM)
b. Axillary buds arise from areas of meristematic
cells left behind at the bases of the leaf primordia.
c. Bud = cluster of leaf primordia created by meristem.
No internodes
d. Lateral branches arise from axillary buds

61. Fig

62. F. Secondary Growth in Shoots
1. Description
a. Shoots of perennials only, not in leaves
b. Occurs in oldest parts of plant
2. Layers (two lateral meristems):
a. Vascular cambium – produces secondary xylem (= wood)
& phloem

63. i. Vascular cambium – layer of cells between primary xylem &
primary phloem. Puts on successive layers of secondary phloem
to outside & secondary xylem to inside =====> stem widens
ii. Dormant in winter, leaves scar when activity resumes ==>
annual ring
iii. Wood = accumulation of secondary xylem. Dead at maturity,
contains lignin

64. b. Cork cambium – replaces the epidermis with
cork: tough, thick cover for stems, roots.
i. Located in the cortex
ii. Produces cork cells to replace epidermis
iii. Periderm = cork + cork cambium
iv. Lenticels = cracks in the periderm that allow gas
exchange for living cells in the interior
v. “bark” = all cells external to the vascular
cambium (secondary phloem & periderm)
vi. Cork continually sloughs off
vii. Growing secondary phloem becomes new cork
cambium (thus no build up of secondary phloem)

65. Fig

66. Fig.35.18

68. Fig

69. G. Secondary growth in roots
1. Description
a. Vascular cambium forms within stele, produces secondary
xylem & phloem
b. Cortex & epidermis shed
c. Cork cambium arises from pericycle & produces the
periderm
d. Periderm – impermeable to water! Thus only young roots
absorb from soil, old roots function = anchor & transport

70. VI. Tissue Arrangement in Plant Parts
A. Roots
1. Epidermis – water, minerals absorbed through
root hairs
2. Stele – central cylinder of vascular tissue
(monocots have slightly different arrangement).
3. Pericycle = outermost layer of stele. Lateral
roots arise from this in order to remain continuous
with vascular system.

71. 4. Ground tissue – mostly parenchyma cells of the
cortex – area between the stele & epidermis; stores food
& takes up minerals.
5. Endodermis – single cell layer between cortex &
stele. Selective barrier for uptake of soil solution
contents into vascular system.

72. Eudicot/Gymnosperm root cross section
Endodermis
Epidermis
Cortex
xylem
phloem
Stele
Fig

73. epidermis pith endodermis xylem phloem cortex pericycle
Fig Cross section of a monocot root

74. B. Stems 1. Eudicots: a. Epidermis
b. Vascular bundles arranged in ring
i. Ground tissue = pith & cortex
ii. xylem faces pith, phloem faces cortex
2. Monocots: vascular bundles scattered throughout
ground tissue

75. Eudicot/Gymnosperm stem cross section pith
cortex
epidermis
phloem
xylem
Sclerenchyma cells
Fig

76. Monocot stem cross-section
Ground Tissue
Epidermis
Vascular bundle
Monocot stem cross-section
Fig

77. C. Leaves Ex. of how structure reflects function – designed for
maximum photosynthetic efficiency
1. Layers:
a. Upper & lower epidermis – tightly interlocked cells,
secrete waxy cuticle. Contains stomata flanked by guard cells
b. Vascular tissue – leaf veins, branch throughout
mesophyll

78. c. Mesophyll – ground tissue between upper & lower epidermis
i. 2 kinds of parenchyma cells:
Palisade – columnar, at top of leaf
Spongy – smaller, below palisade, gas-filled spaces
between cells

79. Fig

80. The fleeting moments captured in engrams of the mind.