Why Protect A Dying Leaf ?
Chapter #42 – Plant Anatomy
& Nutrient Transport
7th Edition in Audesirk, Audesirk, and Byers
Chapter #24 – Plant Anatomy & Nutrient Transport
• 42.1 - How Are Plant Bodies Organized; How Do They Grow? p. 860
• 42.2 - The Tissues and Cell Types of Plants? p. 862
• 42.3 - The Structures, Functions of Leaves, Roots, & Stems? p. 865
• 42.4 - How Do Plants Acquire Mineral Nutrients? p. 873
• 42.5 - How Do Plants Move Water Upward from Roots to Leaves? p. 876
The Art and
Science of
Living
Survive (live)
Support the body
Obtain water & nutrients
Transport water & nutrients
Obtain energy
Grow and Develop
Exchange gases
P? rotection from Herbivory
Reproduce
Angiosperms
(Monocots and Dicots)
• Flowering plants (called Angiosperms) are
divided into two groups (monocots and
dicots) based on the structure of their
flowers, leaves, vascular tissue, roots, and
seeds.
A.
B.
C.
Largest phylum of living plants.
250,000 + species.
Seeds enclosed by fruits.
Plant Anatomy
Roots & Shoots
• Root and shoot
systems are made up
of basic plant
organs: roots, leaves,
stems, flowers.
Root System
Functions
• Anchor plant.
• Absorb water and
minerals.
• Store sugar as
starch.
• Transport materials
• Produce some
hormones.
• Interact with soil
microbes.
Shoot System
Functions
• Photosynthesis
(primarily in leaves)
• Transport of materials
(water, minerals, sugars,
and hormones among
leaves, flowers, fruits,
and roots)
• Reproduction
• Hormone synthesis
Angiosperms
(Monocots and Dicots)
Structure is used in
classification
• Monocots have one cotyledon (seed leaf)
– e.g. grasses, lilies, palms, orchids
• Dicots have two cotyledons (seed leaves)
– e.g. deciduous trees (drop leaves
in winter), bushes, many garden flowers
Flowers
Monocots: flower
parts in 3’s
Dicots: flower parts in
4’s, 5’s, 6’s
Leaves
Monocots:
parallel veins in
leaves
Dicots: network of
veins in the leaves
Stems
Monocots: small
vascular bundles
scattered throughout
the stem.
Dicots: large vascular
bundles arranged in a
ring around the stem.
Roots
Monocots: fibrous
root system with no
main tap root.
Dicots: Main tap root,
with smaller side roots
branching off.
Seeds
Monocots: single
cotyledon; endosperm
and cotyledon are
separate.
Dicots: two cotyledons;
endosperm is contained
in the cotyledon.
Plant Tissues
 Dermal Tissue
- Epidermis
- Periderm
 Ground Tissue
- Parenchyma
- Collenchyma
- Sclerenchyma
 Vascular Tissue
- Xylem
- Phloem
Dermal Tissue:
Epidermis
• Covers flowers,
seeds, fruit.
• Secretes a waxy
substance called
cuticle (cuticular
membrane hydrophobic) as
waterproofing.
• May produce special
structures such as
hairs (root hairs).
Why?
Dermal Tissue:
Periderm
• Replaces epidermis on
roots and stems of
woody plants with
age.
• Composed mainly of
thick, waterproof
cork cells.
• Protects stems and
roots.
• Anchor system
(doesn’t absorb water
& minerals).
Plant Tissues
Parenchyma
Collenchyma
Sclerenchyma
Ground Tissue:
Parenchyma
• Non-dermal, nonvascular.
• Thin-walled cells
• Alive at maturity
• Many functions,
including
photosynthesis,
starch storage,
hormone
production.
Ground Tissue:
Collenchyma
• Flexible support
tissue.
• Elongated cells
with irregular
shapes and
unevenly thickened
walls.
• Living at maturity.
Ground Tissue:
Sclerenchyma
• Support tissue.
• Elongated cells
with thick cell
walls.
• Dead at maturity.
• Forms long fibers,
or smaller sclerids
(such as stone
cells in pears).
Vascular Tissue:
Xylem
• Sclerenchyma fibers
• Long, tube-like cells,
joined end-to-end,
that transport water
and minerals from
soil to leaves.
• Two types of cells:
tracheids (in
conifers) and vessel
elements (in
flowering plants).
Vascular Tissue:
Phloem
• Tissue that
transports dissolved
sugars (sap) in a
plant.
• Two types of cells:
• Sieve tubes (alive
but no nucleus)
• Companion cells
In Review. . . .
Monocots
In Review. . . .
Dicots
Why Protect A Dying Leaf ?