1. Chapter 4 Lessons 3
Herbaceous stems
Characterisitcs:
a.Live only one growing season
b. smaller than a wood stem
c. Important to man as crops
d. No annual rings because live only
one season

2. Dicot herbaceous stems:
Xylem and phloem cells form
fibrovascular bundles arranged in
rings around the pith

3. Dicot herbaceous stems:
Xylem and phloem cells form fibrovascular bundles arranged in rings
around the pith
Xylem is in the center of the ring and the
phloem is on the outside

4. Monocot herbaceous stems
Vascular bundles are scattered
Has a rind or outer covering of the
stem
Usually has no cambium tissue

6. ·
Chapter 4 Lesson 4
·
Vegetative Reproduction – asexual
reproduction from the stem, leaf or
root instead of from seeds.
The Encyclopedia. 2000

7. Vegetative Reproduction – asexual reproduction from the stem, leaf or root
instead of from seeds
· ·
Also called vegetative propagation
The Encyclopedia. 2000

8. In asexual reproduction:
Offspring are genetically identical to
parent
Example is a strawberry that
produces runners

10. Adventitious roots – roots that grow
from unexpected regions of the plant
like the stem, branch or leaf

11. Types of Vegetative propagation
1.Cuttings – piece of stem or root
placed in medium (water or soil) and
roots will grow to make a new plant

12. Types of Vegetative propagation
1. Cuttings
2.Layering – when a portion of a stem
grows roots while still attached to the
parent plant, it will then detach.
Ex. Honeysuckle

13. Types of Vegetative propagation
1. Cuttings
2. Layering
3.Grafting – process of transplanting living
tissue from one plant to another.
Ex. grapes

14. Types of Vegetative propagation
1. Cuttings
2. Layering
3.Grafting
Advantages of grafting:
• saves time – get mature plant
almost immediately
• You get the best attributes of
both plants

15. Types of Vegetative propagation
1. Cuttings
2. Layering
3.Grafting
Terms:
Scion – part that is grafted in
Stock – where the scion is
placed

16. Types of Vegetative propagation
1. Cuttings
2. Layering
3.Grafting
 Method is used for McIntosh apples
and for grapes
 It is mentioned in the Bible
“If some of the branches have been broken off, and you, though a
wild olive shoot, have been grafted in among the others and now
share in the nourishing sap from the olive root, 18 do not consider
yourself to be superior to those other branches. If you do, consider
this: You do not support the root, but the root supports you. 19 You
will say then, "Branches were broken off so that I could be grafted
in." 20 Granted. But they were broken off because of unbelief, and
you stand by faith. Do not be arrogant, but tremble. 21 For if God did
not spare the natural branches, he will not spare you either. “

17. Types of Vegetative propagation
1. Cuttings
2. Layering
3.Grafting
4. Budding – a type of grafting where the
bud is used as the scion.
Typical with apple trees.
Shield-budding the mango. On the left, a bud properly
inserted; next, an inserted bud wrapped with a strip
of waxed cloth; above the knife-point, a properly
cut bud; and on the right, budwood of desirable character.

18. Types of Vegetative propagation
1. Cuttings
2. Layering
3.Grafting
4. Budding
5.Tissue culturing
• Relatively new process
• A cell is placed in a petri
dish with the proper
medium, given hormones, and it will
develop into a new plant

19. Important hormones in plants
1.Auxin
•First group discovered
•Important to root and shoot growth in
tropisms
•causes cells in one area to grow longer

20. Important hormones in plants
1.Auxin
•Secreted in shoot but mainly affect
the root
•Used in root starter when planting
new plants.

21. Important hormones in plants
1.Auxin
2. Cytokinins
• promotes cell division
•secreted mostly in the roots and
affects the shoot
•Auxins and cytokinins work together
to promote growth

22. Important hormones in plants
1. Auxins
2. Cytokinins
3.Gibberellins
• regulate the proper amount of
growth
• If you reduce gibberellins you end
up with dwarf plants.

23. Important hormones in plants
1. Auxins
2. Cytokinins
3.Gibberellins
4. Abscisic acid
•Major role in bud and seed
germination dormancy when plant
stressed due to unfavorable
conditions
•Inhibitory affect
on gibberellins

24. Important hormones in plants
1. Auxins
2. Cytokinins
3.Gibberellins
4. Abscisic acid
5. Ethylene
• responsible for leaf abscission
and fruit ripening.

25. Special stems.
1. Bulbs – ex. Onion; designed for
food storage
2. Rhizomes – thick stems that grow
horizontally under ground
 Store food
 Form of vegetative propagation
 Ex. Iris, grasses

26. Special stems
1. Bulbs
2, Rhizomes
3. Stolons or runners – stem grows
quickly along the surface of the
ground (above ground) to produce
new plants where a node touches
the soil
Ex. strawberry

27. Special stems
1. Bulbs
2. Rhizomes
3. Stolons or runners
4.Tendrils – a stem where hormones
stimulate the cell on the opposite side
to grow longer where the stem
touches an object causing the stem to
wind around the object
Ex. beans

28. Special stems
1. Bulbs
2. Rhizomes
3. Stolons or runners
4. Tendrils
5. Stem Tubers
• Modified portion of stem to store
food
• Also form of asexual reproduction
• Ex. Potatoes
• Also there are root tubers – ex.
yams

29. Special stems
1. Bulbs
2. Rhizomes
3. Stolons or runners
4. Tendrils
5. Stem Tubers
6. Thorns
• Modified portion of stem for
protection
• Ex. Honey locust
• Don’t confuse with spines which
are modified leaves

30. Roots
Two types of roots are:
A. Fibrous roots
 Branching – main central root
 Monocots have them
 Ex. grasses

31. Roots
Two types of roots are:
A. Fibrous roots
B. Tap roots
 Have an enlarged main root
 Dicots have them
 Ex. carrots, dandelions

32. Roots
Parts of a root cross section:
1. Epidermis – outside layer that
protects the root from water loss

33. Roots
Parts of a root cross section:
1.Epidermis
•Root hairs – are projections of the
epidermis that increase the surface
area of the root for better water
absorption.

34. Roots
Parts of a root cross section:
1.Epidermis
•Root hairs
2. Cortex – the next layer in from the
epidermis and is where food is
stored.

35. Roots
Parts of a root cross section:
1.Epidermis
•Root hairs
2.Cortex
3. Stele – central cylinder of the root
that contains the xylem and phloem.

36. Roots
Three regions of primary root growth:
a. Meristemic region – region closest to
the end where cell division takes place

37. Roots
Three regions of primary root growth:
a. Meristemic region
a. Region of elongation – just above
the meristemic region and is where
cells will increase in length pushing
the root down

38. Roots
Three regions of primary root growth
a. Meristemic region
b. Region of elongation
c. Maturation region – where cells
become specialized and incorporated in
the stele/cortex.

39. Roots
Root Cap –
 is at the end of the root protecting and
covering it
 is several cell layers
thick
 Secretes slime to reduce
friction

40. Roots
Secondary Growth or lateral growth:
 Takes place in the cambium tissue
 Addition of new xylem and phloem
by vascular
cambium cells

41. Roots
Specialized root functions:
1. Prop roots
 adventitious roots that arises
from the stem
 add support
 Ex. corn

42. Roots
Specialized root functions:
1. Prop roots
2. Bald cypress knees
 Stick above the water
 Presumed to provide
oxygen to other roots but
no scientific evidence
 Give added support??
 Purpose unknown

43. Roots
Specialized root functions:
1. Prop roots
2. Bald cypress knees
3. Desert plant roots– secrete
chemical inhibitors to keep other
plants from growing nearby.