Edited version of the first PowerPoint presentation done on Primary Plant body. this

1. BOTANY 103
Chapter 4
Presented by:
Fasama Hilton Kollie
Lecturer, Department of Biology
Mother Patern College of Health Sciences

2. LESSON OUTLINE
1. Overview of Vascular Plants
2. Overview of Plant Growth and Development
3. Plant Embryology
4. Plant Growing Seasons
5. Plant Organs

3. LESSON OBJECTIVES
By the end of this session, learners will be able to;
• Define vascular plant, plant embryology and plant organ
• Identify the basic plant organs
• Describe plant embryonic structures
• Describe root, stem and leaves
• Identify the general functions of roots, stems and leaves

4. Overview of Vascular Plant
Organs
• What are vascular plants?
• Plant organs are made from simple and complex tissues that
adapts as a group to perform particular functions
• Vascular plants have three types of organs:
‒ Root
‒ Stem
‒ Leaves

5. • Root has two main functions:
‒ Anchoring the plant in the soil
‒ Absorption of water and
minerals
• Many roots store food for the
plant. Eg: carrot and sweet
potatoes
Fig03. Plant Root

6. Stem:
• Stems vary greatly in size, such as a
slender stalk supporting a small flower
• All stems display leaves in the best
position for photosynthesis
• Stems provide pathways for the
transport of leaves products to roots
Fig01. Typical plant structure

7. • Leaves serve as the site of
photosynthesis
• They are an extension of the plant’s
vascular tissue system
• Leaves do not only conduct water but
also provide most of the pressure that
actually forces the water through the
plant’s body
Leaves:

8. Plant Growth & Development
• At every structural level – from cells to tissues to organs - a plant is a
complex, dynamic organism
• Plants and other multicellular organisms develop from a single cell
• Initiated through cells division, elongation and specializing for different
functions
• Development in plants can be seen typically in seed plants
‒ Gymnosperms
‒ Angiosperms

9. • The body of a typical
plant can be described as
having two connecting
systems:
1. Root system
2. Shoot system
Fig04. Plant Connective system

10. • The process that produces a plant embryo from a fertilized ovule
by cell division and the differentiation of undifferentiated cells into
tissues and organs
• A seed plant embryo includes the following embryonic organs that
develops into root and shoots:
Cotyledon > Radicle > Plumule > Epicotyl > Hypocotyl
Plant Embryology

11. • “Seed leaves”
• Consist of one or more seed leaves
• Main function: Stores food for the
germinating seed
Plant Embryology
Cotyledon:
Germinating embryo reviewing cotyledon

13. • “Embryonic root”
The part of a plant embryo
that develops into the primary
root
Radicle:
Plumule:
• “Embryonic shoot”
The rudimentary shoot of an
embryo plant
Plant Embryology

14. • “Embryonic stem”
• The tiny shoot, which develops
into stems, leaves and flowers
of the plant future
• The stem of a germinating
seedling, found below the
cotyledons and above the
radicle
Epicotyl
Hypocotyl
Diagram showing epicotyl and hypocotyl of bean

16. • Plants with secondary growth are known informally as
woody plants
• Herbaceous plants
• Plants have indeterminate growth
• Plant can be categorized into three distinct groups based on
how long they live:
→ Annual, Biennial and Perennial plants
Plant Growing Seasons

17. Annual Plants
• An annual is a plant that completes its life cycle during a
single growing season
• Herbaceous plants
• Eg: Marigolds, beans, corn etc
Beans Marigolds

18. • Requires two growing seasons to complete its life cycle
• Typically herbaceous plants
• Eg: Carrots, beets, cabbage etc
Biennial Plants
Carrots
Cabbage

19. • Grows for more than two years
• Most are woody plants
• Eg: Trees, shrubs
Evergreen Tree Dragon blood tree
Perennial Plants

20. Roots, Stems, & Leaves

21. Plant Organs
• Plant body has two connecting
systems;
• The root system consists of all
components below ground
• Shoot system consist of all plants
component above ground

22. • In vascular plants, the root is the organ of a plant that typically
lies below the surface of the soil
• Roots can also be aerial or aerating, that is growing up above the
ground or especially above water.
• Radicle is a plant first root
Plant Organs: ROOT

23. • FUNCTIONS OF ROOT
• Anchoring of plant firmly in the soil
• Absorption and conduction of water and inorganic nutrients
• Storage
• Vegetative reproduction
• Production of Hormones
Plant Organs: ROOT

24. Plant Organs: ROOT
• TYPES OF ROOTS
• On the basis of their origin there are two main patterns
of root growth:
→ Taproots System
→ Adventitious Root Systems

25. • The largest, most central, and most
dominant root from which other roots
sprout laterally
• It develops directly from the radicle
• Taproot produces branch roots called
lateral roots
ROOT : Taproot System

26. ROOT : Taproot System
Carrot
Cycads
Conifers

27. • Roots that develop from any other part
of a plant body either than the radicle
• Fibrous roots grow fairly close to the
surface of the ground
• few plants with fibrous root systems:
Coconut palm, Grass, Onion
ROOT : Adventitious Root System
Grasses

28. IDENTIFY THE
TYPE OF ROOT
SYSTEM
SELF TEST
AB

29. Root cap:
• Apical meristem of root consist of a root cap with
several layers of cells
• Root cap produce slimy polysaccharide know as
mucigel
• This lubricate the passage of the root through the soil
ROOT : Root Structure

31. • Root development occurs near the root tip, in the apical
meristem
• Development is initiated by Initials
• Initials are located within small spherical center of the meristem
called Quiescent center
• Initials and derivative cells can rebuild damaged or destroyed
apical meristem
ROOT : Root Development

32. • Cell division in a root or shoot apical meristem produces the
derivative that becomes the primary meristems: Protoderm,
Ground Meristem and Procambium
• In a root, division, growth, and differentiation of cells can be
traced linearly through three overlapping regions;
• Zone of Cell Division
• Zone of Elongation
• Zone of Maturation
ROOT : Root Development

33. Zone of Cell Division, Elongation and Maturation

34. • In a cross section or transverse section, the root presents the
following structures:
̶ Stele
̶ Epidermis
̶ Cortex
Stele:
• The central part of a root or stem
− Endodermis
− Pericycle
− Vascular tissues
ROOT : Anatomy of Root

35. CROSS SECTION- Internal Stuctures of a Root
Epidermis
Cortex
Endodermis
Pericycle
Xylem
Phloem
Stele
Root
hair

36. • Protostele: is the most simplest type of stele and the earliest to
evolve
• In the root of most seed plants, two important cell layers called the
pericycle and the endodermis surround the stele
• Pericycle: a cell layer immediately encircling the stele that gives
rise to lateral roots
• Endodermis: the layer of cells around the stele that regulates the
flow of substances between cortex and vascular tissue

37. A
F
D
B
C
E
G
SELF TEST
Epidermis
Pericycle
Phloem
Endodermis
Xylem
Cortex
Root hair

38. Aerial Root:
• A modified adventitious root that arise from
stem tissue
• Found in plants that grow on other plants
for support and nourishment (Epiphyte)
• Provides additional support for a plant such
as water retention, photosynthesis, and
support.
• Eg: Corn
ROOT : Modified Roots
Corn

39. • Flared roots that extend from tree trunks
• Provide stability to plants in thin soils
• Eg: Fig tree
Buttress Roots
Fig tree

40. • A thickened specialized root at the
base of a corm, bulb, rosette or
other organ
• Usually broad, fleshy, vertical,
tapering, wrinkled looking
• Found in lilies
Contractile Roots:
Water lilies

41. • Also known as air roots
• Eg: Mangrove
Pneumatophores:

42. • Modified parasitic roots
• Eg: Mistletoe
Haustoria:

43. • Roots often form mutualistic or beneficial associations with
other organisms
• Mycorrhizae
• The two main types of these associations are;
• Endomycorrhizae
• Ectomycorrhizae
Root Relationship With Other
Organisms

44. MYCORRHIZAE

45. • A part of a plant that supports leaves or
reproductive structures
• They may vary in size, such as from a
slender stalk to a big tree trunk
• First stem of a plant develops from part of
a seed embryo called Epicotyl
PLANT ORGANS: STEM

46. • Transport water and solutes between
roots and leaves
• Produces & support appendages of
plant (leaves, flowers, fruits)
• Stems in some plants are photosynthetic
• In some plants, stems have become
adapted for specialized functions such as;
Storage etc Cauti
Stem Function

47. • Node: A node is a point on the stem from which
leaves or buds arise
• Internode: The portion between two successive
nodes
• Buds: A bud is an undeveloped or embryonic
shoot
– Three types of buds based on location, namely: Terminal
buds, Axillary buds and Adventitious buds
External Structure of Stem

48. • Internal structure of a dicot
stem reveals the following
features:
• Epidermis, Cortex, Pericyclic
• Vascular Bundles and Pith
Internal Structure of Stem

49. • Alternate arrangement: one leaf per
node, it may form a spherical or helical
pattern
• Opposite arrangement: two leaves per
node. Each pair of leaves is oriented like
the previous pair
• Whorled arrangement: three or more
leaves per nodes.
Arrangement of Leaves on a Stem

50. • Specialized stems are: Stolon, rhizomes, tubers, bulbs, corms etc
STOLON
• Horizontal stem aboveground
• Stolon often originate as axillary buds
• They help a plant reproduce asexually
• Eg: Bermuda grass, spider plant, ferns
RHIZOMES
• Underground horizontal stems with
adventitious roots
• Rhizomes are used to store starches
and proteins
• Eg: Irises, grasses, ginger
Modified Stems

51. TUBERS
• Underground stems that store
food
• Usually swollen
• The “eyes” of a potato (Irish
potatoes, Solanum tuberosu)
are the nodes of a starch-
ladened stem
BULBS
• Large buds with a small stem
at the lower end surrounded
by numerous fleshy leaves
• Leaves stores nutrients
• Adventitious roots at the
base
• Eg: Onion, tulip, daffodil and
Lily
CORMS
• Composed entirely of stem
tissue surrounded by a few
papery scale like leaves
• Adventitious roots at the
base
• Eg: Crocus and gladiolus
Modified Stems

52. • A leaf is a thin, flattened organ,
above ground and specialized
for photosynthesis
• Originates from a precursor named
leaf primordia
• This develops into a leaf through cell
division, growth, and differentiation
PLANT ORGANS: LEAVES

53. • Photosynthesis is the primary function of
the leaves
• It function in water retention in desert
plants. Eg: Cactus
• Function during transpiration
• Function in translocation via the leaf veins
Function of Leaves
Cactus Plant

54. • A leaf can be either;
Simple Leaf or Compound Leaf
• A simple leaf is a single leaf that
attaches to the stem
• A compound leaf is a leaf that is
composed of two or more leaflets
on a common stalk
Types of Leaves

55. Morphology of Leaves

56. • Leaves can be found in a variety
of shapes and sizes
• The Basic leaf features of plants
include:
• Leaf blade
• Petiole
• Stipules
Tip
Midrib
Margin
VeinPetiole
Blade (Lamina)
Parts of a Leave

57. BLADE:
• The broad portion of a leaf.
– Apex - leaf tip.
– Margin - leaf edge boundary area.
Margins can be smooth, jagged
(toothed), lobed, or parted.
– Veins - vascular tissue bundles that
support the leaf and transport
nutrients.
– Midrib - central main vein arising
from secondary veins.
– Base - area of the leaf that connects
the blade to the petiole.

58. • PETIOLE - thin stalk that
attaches the leaf to a stem
• STIPULES - leaf-like
structures at the leaf base.

59. • Leaf tissues are composed of layers of plant cells
• Different plant cell types form three main tissues found in leaves
• A typical leaf has three regions, namely: Upper epidermis,
Mesophyll tissue layer and Lower epidermis
Leaf Tissues In Cross Section

60. • It is the outer layer of a leaf
• Epidermis protects the leafs from water loss, abrasions
• It secretes a waxy coating called cuticle that helps the plant
retain
• It has tiny pores called stomata
• Guard cells regulates the opening and closing of the stomata
Epidermis

61. STRUCTURE OF A LEAF

62. • The middle mesophyll leaf layer is composed of;
• Palisade mesophyll and a Spongy mesophyll
• Palisade mesophyll contains columnar cells with spaces between
the cells
• Spongy mesophyll is located below the palisade mesophyll
• It is composed of irregular shaped cells
Mesophyll

63. • Like other organs, leaves are often modified for functions other
than photosynthesis. Below are a few examples:
• Insect-trapping leaves
• Leaves modified for
reproduction
• Prophylls
• Cotyledons
• Tendrils
• Stipule
• Spines
• Storage leaves
Specialized Leaves

64. • A tendril is a specialized leave or
petiole with a threadlike shape
• Used by climbing plants for
support or attachment
Tendril Stipule
• An outgrowths borne on either
side of the base of a leafstalk
• Used like leaves to make
energy for the plants

65. Insect-trapping Leaves
• Insect-trapping leaves are leaves
that are specialized to trap insects
Spines
• Spines are hard, sharp leaves that
are specialized to defend the plant
from being eaten by animals

66. REFERENCE
• Nabor, Murray W., INTRODUCTION TO BOTANY. Copyright 2004 Pearson
Education, Inc., Publilshing as Benjamin Cummings, 1301 Sansome St., San
Francisco, CA 94111.
www.aw-bc.com