1. Plants

2. Plant Evolution and Classification
Preventing Water Loss
Reproducing by Spores and Seeds
Transporting materials throughout the plant.

3. Classifying Plants 2 groups based on the presence of vascular tissue
Nonvascular Plants
Vascular Plants
Seedless-fern like
Seeded- Maples, and Pine

4. Classification Nonvascular Plants Phylum Bryophyta
Phyla Haptophyta and Anthocerophyta

5. Seedless Vascular Plants
Phylum Psilotophyta
Phylum Lycophyta
Phylum Sphenophyta
Phylum Pterophyta

6. Vascular Seed Plants Gymnosperms Angiosperms Phylum Cycadophyta
Phylum Ginkgophyta
Phylum Gnetophyta
Phylum Coniferophyta
Angiosperms
Phylum Anthophyta

7. Classes of Angiosperms
Monocot
On cotyledon
Parallele Venation
Scattered
Flower parts in 3’s
Fibrous
Dicot
2 cotyledons
Net venation
Radially arranged vascular bundles
Flower parts in 4 and 5
Taproot

11. Plant Structure and Function
Plant Cells
3 types
Parenchyma
Collenchyma
Sclerenchyma

12. Parenchyma
Loosely packed cube-shaped or elongated cells that contain large central vacuole.
Metabolic functions, photosynthesis and storage of water and nutrients.
Example~ Fleshy part of an apple

13. Collenchyma Cells Thicker cell walls, irregular shape
Usually grouped in strands and are specialized for supporting regions that are still growing.
Celery

14. Sclerenchyma Cells Thick rigid cell walls.
Support and strengthen the plant in areas where growth is no longer occurring.
Gritty texture of a pear fruit.

16. Tissue Systems
Dermal Tissue
Ground Tissue
Vascular Tissue

17. Dermal Tissue Forms the outer coverings in plants
Consists of the epidermis, the outer layer made of parenchyma cells.
Roots~ absorption, protection
Stems~ gas exchange, protection
Leaves, gas exchange, protections.

18. Ground Tissue
All 3 cell types
Storage, metabolism and support.

19. Vascular Tissue Functions in transport and support Xylem-dead
Phloem-living
2 major components for xylem
Tracheid
Vessel Element

20. Tracheid Long thick walled sclerenchyma cell with tapering ends.
Water moves from on tracheid to another through piths

21. Vessel Element
A sclerenchyma cell that has either large holes in the top and bottom or no end wall at all.
Stacked to form long tubes called vessels.

22. Sieve Tube Member Conducting parenchyma cells of angiosperm phloem.
Compounds move from one to another through sieve plats.
Each cell has a companion cells, specialized parenchyma cell.

23. Growth in Meristems (Primary Growth)
Meristem- regions where cells continuously divide for plant growth.
Apical Meristem- located in the tips of stems and roots.
Intercalary meristems- growth between the nodes of plants.

24. Root Structures

25. Root Structures Root Cap Root Hairs
Covering of cells that protects the apical meristem.
Produces a slimy lubricant.
Root Hairs
Extensions of the epidermal cells.
Increase the surface area.

26. Primary Growth in Roots
Roots increase in length
cell division
elongation
maturation in the root tip
Dermal tissue matures to form the epidermis
Ground tissue matures into 2 regions
Cortex and Endodermis

28. Cortex Located just inside the endodermis.
Largest region of the primary root.
Parenchyma cells

29. Endodermis Inner cylinder of the cortex.
Vascular tissue in roots matures to form the innermost cylinder
Dicots and gymnosperms~ xylem makes of the central core of the root.

30. Monocot Root Cross Section

31. Dicot Stem

32. Stems

33. Primary Growth in Stems
Apical meristems give rise to the dermal, ground and vascular tissue.
Dermal- epidermis
Ground- cortex and pith
Cortex- just inside the epidermis
Pith- located in the center of the stem.
Vascular- xylem and phloem

34. Monocot Stem

35. Vascular Bundle of Monocot

36. Dicot Stem

37. Secondary Growth Conifers and Woody dicots
Increases in girth or lateral dimension
Occurs at lateral meristems
Vascular cambium
Gives rise to secondary xylem and phloem
Cork cambium
Gives rise to bark

38. Vascular Cambium Cells on the outside differentiate into phloem
Cells on the inside differentiate into xylem
Only new xylem transports water.
Older xylem located at the center is only for support.

39. Annual Rings

40. Leaves

41. Monocot Leaf
Upper Epidermis
Mesophyll
Lower Epidermis
Xylem
Phloem

42. Dicot Leaf Upper Epidermis Xylem Palisade Mesophyll Spongy Mesophyll
Phloem
Lower Epidermis
Guard Cells with Somata

43. Leaf Structures Epidermis Palisade Mesophyll Spongy Mesophyll
Guard Cells
Vascular Bundles

44. Epidermis A protective covering of one or more layers of cells.
Covered by the cuticle
Cutin
Transpiration

45. Palisade Mesophyll
Parenchyma cells
Numerous chloroplasts

46. Spongy Mesophyll Parenchyma cells Loosely arranged
Air spaces allow for gas exchange

47. Guard Cells
Specialized epidermal cells that control the opening and closing of stomata.
Controls gas exchanges with the environment.

48. Vascular Bundles Consists of xylem and phloem tissues
Contains bundle sheath cells that prevent gas from entering the vascular bundle.

49. Transport of Water
Water and dissolved minerals enter the roots through root hairs by osmosis.
2 Possible Pathways
Apoplast
Symplast

50. Apoplast
Water moves through cell walls from one cell to another without every entering the cells.

51. Symplast Water moves from one cell to another through the symplast.
Water moves from the cytoplasm of one cell to the cytoplasm of the next through plasmodesmata.
Small tubes that connect the cytoplasm of adjacent cells.

52. When water reaches the endodermis…
Water can continue into the vascular cylinder only through the symplast pathway.
Water that is moving via the apoplast pathway is blocked by the suberin that permeates the casparian strip.
Water can enter through the endodermal cells along with K+, but Na+ is blocked.
Water then reaches the vasuclar cylinder where xylem tissue (tracheids and vessels) conduct the water up the plant.

54. Water Movement Up the Plant
3 Mechanisms
Osmosis
Capillary Action
Cohesion-tension theory

55. Cohesion-tension Theory
3 Major Concepts
Transpiration
Cohesion
Bulk Flow

56. Transpiration The evaporation of water from plants.
Water evaporates through the leaves creating negative pressure to develop in the column.

57. Cohesion The molecular attraction between like substances.
The water molecules “stick” together creating a single column of water molecules.

58. Bulk Flow
When a water molecule is lost from a leaf by transpiration it pulls up behind it an entire column of water molecules.

60. Transport of Sugars 4 Step process
Sugars enter the sieve-tube members via active transport.
Water enters the sieve-tube members.
Pressure in sieve-tube members at the source moves water and sugars to sieve-tube members at the sink through sieve tubes. As a result pressure builds causing the water and sugars to move.
Pressure is reduced in sieve-tube members at

61. Plant Movements Tropisms Nastic Movements
A plant movement that is determined by the direction of an environmental stimulus.
Positive
Negative
Nastic Movements
Plant movements that occur in response to environmental stimuli but are independent of the direction of the stimuli.

62. Tropisms
Phototropism
Thigmostropism
Gravitropism

63. Phototropism Stimulus Hormone Function Light Auxin
Light causes the production of auxin to move to the shaded side.
As a result the cells on the shaded side are elongated faster then the lighted side.
The plant bends towards the light.

64. Thigmotropism Stimulus Function Contact with an object
Allows for vines to “climb” walls.
Tendrils will coil around objects.

65. Gravitropism Stimulus Hormone Function Gravity Auxins, Gibberellins
Allows for roots to grow down.
Allows for shoots (stems) to grow up at the apical meristem.

66. Photoperiodism
Is the response of plants to changes in the photoperiod, or the relative length of daylight and night.
Plants maintain a circadian rhythm
External clues such as dawn and dusk reset the clock.

67. Phytochrome
The protein involved used in maintaining the circadian rhythm.
2 Forms depending on the wavelength of light that the phytochrome absorbs.
Pr: Phytochrome red (wavelength of 660nm)
Accumulates at night
Pfr: Phytochrome far-red (730nm)
Resets the circadian-rhythm clock
Reversible relationship between Pr and Pfr
When Pr is exposed to red light it is converted to Pfr
When Pfr is exposed to far-red light it is converted to Pr

68. Critical Night Length
CNL is responsible for resetting the circadian-rhythm clock.
Brief dark periods during the day have no effect on the clock.
Flashes of red light at night cause the clock to be reset.

69. Flowering in Plants Regulated by the photoperiod. 3 types of plants
Long-day
Plants flower in the spring and early summer when day light is increasing.
Short-day
Plants flower in late summer and early fall when daylight is decreasing.
Flower when daylight is less than a critical length.
Day-neutral
Do not flower in response to daylight changes.