1. Lesson 2.2
Plants have 3 distinct tissue
types:
1. Structural tissue
• composes most of the plant
• four types:

2. Lesson 2.2 Internal leaf structure
Plants have three distinct tissue types:
1. Structural tissue
Four types
A. Epidermal
•protects and covers
•is covered by a cuticle (waxy layer)
to prevent water loss and injury
• Like plant’s skin
• Is a single layer of cells

3. Epidermal layer
Cuticle causes water
to bead on leaves.

4. Lesson 2.2 Internal leaf structure
•Plants have three distinct tissue types:
1. Structural tissue
• four types:
A. Epidermal
B. Cork
•replaces the epidermis as a plant
grows
• forms outer bark
•protective layer
•water proofs the stem
•not found in herbaceous plants

6. Lesson 2.2 Internal leaf structure
1. Structural tissue
• four types:
A. Epidermal
B. Cork
C. Parenchyma
Found on the roots, stems
and leaves
Carries out photosynthesis
stores food

8. Lesson 2.2 Internal leaf structure
1. Structural tissue
• four types:
A. Epidermal
B. Cork
C. Parenchyma
D. Support/strengthening tissue
• fibers run through stems, roots
and veins of leaves
• thick walled
• walls remain after dead for
support

9. Lesson 2.2 Internal leaf structure
•Plants have three distinct tissue types:
1. Structural tissue
2. Vascular tissue (transport)
•sap containing
•found in stems, roots and
veins/petioles of leaves

10. Lesson 2.2 Internal leaf structure
•Plants have three distinct tissue types:
1. Structural tissue
2. Vascular tissue (transport)
Two types of vascular tissue:
A.xylem – transports water and
minerals upward
B.phloem – transports food from the
leaves to other parts of plant

12. Lesson 2.2 Internal leaf structure
•Plants have three distinct tissue types:
1. Structural tissue
2. Vascular tissue
3. Meristem
•function is for growth and repair
•found in certain areas where
growth takes place
•produces undifferentiated cells

13. Lesson 2.2 Internal leaf structure
•Plants have three distinct tissue types:
1. Structural tissue
2. Vascular tissue
3. Meristem
Two types of meristem:
A. Apical meristem
 promotes growth in height
 Found in buds and growing roots

14. Lesson 2.2 Internal leaf structure
•Plants have three distinct tissue types:
1. Structural tissue
2. Vascular tissue
3. Meristem
Two types of meristem:
A. Apical meristem
B. Lateral meristem
Promotes growth in width
Two types:
• vascular cambium – produces new
vascular tissue
• cork cambium – produces new
cork tissue (bark area on tree)

16. Transpiration – loss of
water vapor from leaves
and stems

18. Three things that
reduce
transpiration are:

19. 1. Cuticle – waxy covering on
some leaves

20. 2. Guard cells – open and close
leaf pores (stomata)

21. 3. Leaf hairs – hair-like
structures which form from the
epidermis and reduce
transpiration by reducing wind
speed across the leaf
Electron microscope
picture of leaf hairs

22. Leaf structures – cross section:
1.Upper and Lower epidermis
protects and reduces water
loss
Like skin of plant
 cuticle
on top of
epidermis

23. Leaf structures:
1. Upper and Lower epidermis
2. Mesophyll
middle portion of leaf
Two layers of mesophyll:
Palisade – where most of
photosynthesis takes place
Spongy -where gases and
water are stored

25. Leaf structures:
1. Upper and Lower epidermis
2. Mesophyll
3. Stomata – Stoma (singular)
• Tiny openings for gas
exchange
• Protected on each side by
guard cells
• Where water exits during
transpiration

26. Stomata

27. Leaf structures:
1. Upper and Lower epidermis
2. Mesophyll
3. Stomata
4. Guard cells
• Open and close the stomata

28. Leaf structures:
1. Upper and Lower epidermis
2. Mesophyll
3. Stomata
4. Guard cells
5. Veins
 Contain the sap
 Run through mesophyll

29. Venation Patterns
1. Palmate – veins radiate
from a central point at the
base of the leaf; like the palm
of the hand. Ex. maple

30. Venation Patterns
1. Palmate
2.Pinnate – has one main vein
with smaller ones branching
off; Ex. oak

31. Venation Patterns
1. Palmate
2. Pinnate
3. Parallel - veins run parallel
for the length of the leaf, from
the base.
Ex. Lily leaf

32. PLANT CELLS
oCell – basic unit of all living
things

33. PLANT CELLS
oAll cells are made up of 4
main elements:
 carbon
 hydrogen
 oxygen and
 nitrogen

34. PLANT CELLS
These 4 main elements
form major compounds of
all living things:
 carbohydrate
 lipids(fats/oils)
 proteins, and
 nucleic acid

35. The main parts of all cells:
1. Cell membrane
 defines the cell and contains
the cytoplasm and organelles
within
 Regulates what goes in and out
of cell

37. The main parts of all cells:
1. Cell membrane
2. Cytoplasm - Jelly-like fluid
where organelles and nucleus are
suspended

38. The main parts of all cells:
1. Cell membrane
2. Cytoplasm
3. Nucleus
 Contains genetic information
(DNA)
 Controls cell activities
 Spherical shaped body near
center of the cell

39. The main parts of all cells:
1.Cell membrane
2. Cytoplasm
3. Nucleus
4. Organelles
 Tiny organ-like
structures of the cell
 See Handout

40. Cell parts only in plants:
1. Cell wall
 Made of cellulose
 Only plant cells have them not
animal cells
 Humans are not able to digest
cellulose, but is good bulk for diet

41. Cell parts only in plants:
1. Cell wall
 Cellulose strengthens but
allows for flexibility in plants
•Cellulose is important to many
industries such as the paper
industry

42. Cell parts only in plants:
1. Cell wall
•Some cell walls also have lignin
adding more stiffness to the cell
wall of woody stems.

43. Cell parts only in plants:
1. Cell wall
2. Chloroplast and chlorophyll
Chloroplast
•Organelle containing chlorophyll
•Most numerous in palisade
mesophyll
• Site of photosynthesis

45. Cell parts only in plants:
1. Cell wall
2. Chloroplast and chlorophyll
Chlorophyll
•Green pigment found in the
chloroplast
•Traps energy from sunlight
•Important to photosynthesis

46. Cell parts only in plants:
1. Cell wall
2. Chloroplast and chlorophyll
3. Vacuoles
oStorage of food and water
oUsually 1 or 2 large ones

47. Differences between plant and animal
cells:
Plant Animal
Rectangular shape round shape
1 large vacuole many small
Larger than animal smaller than
cell plant cell