Download plant structure

What Plant Parts Do You Eat?
• 1. What are some vegetables that you have
eaten?
• 2. Do you know what plant parts these
vegetables come from?
Let’s Take a Look at Some
Vegetables…
• 1. Carrot
– Is a root
– It is so wide because the plant ends up taking
in more food than it can use, and so it stores
the extra food in its roots. Then these roots
get bigger and bigger until we pull them up
and eat them
• 2. Celery
– Is a stem
– Is used as a medicine for joint and urinary
tract inflammations. The whole plant is
gently stimulating, nourishing and
restorative.
• 3. Onion
– Is a stem that grows underground
– Is a bulb, which is made up of a central stem
surrounded by short, thick leaves. The
leaves wrap around and protect the stem
and also store food. May remain dormant
for a long time, yet still grow into a plant
• 4. Potato
– Is a stem that grows underground
– Is a tuber, which stores food.
– The spots on a potato are called eyes. They
are actually undeveloped buds where new
plants can grow from. So if we wanted to
grow more potato plants, we could cut a big
potato into small pieces and plant the pieces
that have at least one eye.
• 5. Cabbage
– Are leaves
– Leaves of a cabbage head are packed very
tightly next to each other
• 6. Broccoli
– Is a stem with green, fleshy flower heads
– Is a good source of vitamins A & C, iron,
calcium and also provides fiber. Eating
more broccoli can reduce the risk of getting
cancer.
– We are eating 900% more broccoli today
than 20 years ago!
• 7. Corn kernel
– Is a type of fruit called a caryopsis,
which is a kind of fruit with a single
seed.
– Each corn fruit only has one seed.
– Also the seed coat is fused with the
inner wall of the fruit so you can
not separate the seed from the rest
of the fruit.
– A caryopsis is dry and hard when
the fruit is ripe.
PLANT STRUCTURE
Flowering
plants
Conebearing
plants
Ferns and
their relatives
Flowers; Seeds
Enclosed in Fruit
Mosses and
their relatives
Seeds
Chapter 23
BIO 392
Water-Conducting
(Vascular) Tissue
Green algae
ancestor
Remember…
• Organisms are made up
• Plants are made up of:
of:
– 1. Organ Systems
1. Organ Systems
– 2. Organs
– 3. Tissues
2. Organs:  Roots, Stems, Leaves
– 4. Cells
3. Tissues:  Dermal, Vascular,
Ground, Meristematic
4. Cells: epidermal cells, tracheids, vessel
elements, sieve tube elements,
companion cells, parenchyma,
collenchyma, sclerenchyma,
3 Plant Organs
• Roots
• Stems
• Leaves
Root, Stem, and Leaf Tissues
Section 23-1
Leaf
Stem
Root
Dermal tissue
Vascular tissue
Ground tissue
Concept Map
Section 23-1
Plant Tissues
include
Dermal
tissue
Meristematic
tissue
includes
Epidermal
cells
includes
Xylem
includes
Tracheids
Vascular
tissue
Vessel
elements
Ground
tissue
includes
Phloem
Parenchyma
cells
includes
Sieve tube
elements
Companion
cells
Collenchyma
cells
Schlerenchyma
cells
4 PLANT TISSUE SYSTEMS (cont.)
A) DERMAL TISSUE  The outer covering of the plant
1. “the skin”
2. may have a  waxy covering to prevent water loss
B) VASCULAR TISSUE: Transports  fluids,nutrients,food
throughout the plant
1. “the bloodstream”
2. Xylem: transports  water
3. Phloem: transports  food (sugars made)
C) GROUND TISSUE  everything else
4 PLANT TISSUE SYSTEMS
D) MERISTEMATIC TISSUE  Source of new growth for
the entire life of the plant
1. Primary Growth: plants grow  taller and deeper
a. Only in tips of roots & shoots
b. Apical meristem =  “the bud”
2. Secondary Growth: plants grow  wider
a. Lateral meristem tissue
b. Also known as vascular or cork cambium
Root
Words
Section 23-2
The word root is not used only by biologists.
Read over each of the following sentences. Try to
determine the meaning of the boldfaced word(s)
in each sentence. Then, explain how each use of
the word root is related to the root of a plant.
1. The love of money is the root of all evil.
2. Tired of moving from place to place, he took root in our hometown.
3. The police were determined to root out the criminals.
ROOTS
A. FUNCTION
1. Absorbs  water & dissolved nutrients/minerals from
soil
2.  Anchors plant & prevents erosion
B. TYPES:
1. Taproots  long & thick,
2. Fibrous roots  thin & branching
ROOTS (cont.)
C. STRUCTURE
& TRANSPORT
1. Outer epidermal layer
a. covered by tiny  root hairs = more surface area
= more absorption
b. contain  active transport proteins in their cell
membranes to pump minerals from soil into plant.
c. water follows by osmosis
ROOT STRUCTURE cont.
2. Large layer of Ground tissue
a. spongy cortex
b.  endodermis encloses vascular tissue
i. cells are surrounded by  Casparian strips
- waterproof barriers that force water
to go THROUGH cells, not around.
- Keep flow one way (osmosis = high to low)
3. Central Vascular cylinder
a. water moves into the  xylem
b. because it cannot go backward, the only
place to go is  up the stem
i. this is called  “Root Pressure”
Section 23-2
The Structure of a Root
Epidermis
Endodermis
Root hairs
Ground tissue
(cortex)
Phloem
Xylem
Vascular
Cylinder
Ground tissue (cortex)
Epidermis
Endodermis
Vascular cylinder
Zone of
maturation
Zone of
elongation
Apical meristem
Root cap
Cross Section of Plant Root
(magnification: 40x)
Stem Study
Imagine walking through a botanical garden. You
probably would see many different kinds of plants, such
as small and large trees, flowering plants, and cacti.
1. How do the stems of trees, flowering plants, and cacti differ?
2. How are the stems of these plants similar?
A. FUNCTION
STEMS
1.  Support; hold leaves up in the sunlight
2.  Transport substances between roots &
leaves
B. TRANSPORT
1. Capillary Action
a. water moves by  cohesion from roots
b.  one-way
2. Nutrients are transported through stem
a.  in phloem
b.  in 2 directions
Leaves: Up Close and Personal
Section 23-4
Pin oak
Dandelion
Eastern
white pine
1. Describe the shape of each leaf.
2. Describe the features of each leaf.
3. How is the structure of a leaf related to its function?
LEAVES
A. FUNCTION
1.  Site of photosynthesis
B. STRUCTURE
1.  Epidermis is covered by cuticle
a. reduces evaporation
2.  Mesophyll – specialized ground tissue
a. lots of chloroplasts
b. where photosynthesis occurs
3. Veins of xylem & phloem branch
The Internal Structure of a Leaf
Section 23-4
Cuticle
Veins
Epidermis
Palisade
mesophyll
Xylem
Vein
Phloem
Spongy
mesophyll
Epidermis
Stoma
Guard
cells
LEAVES cont.
C. SPECIAL STRUCTURES
1. Stomata: exterior openings on underside of leaf.
 Site of gas exchange (pores)
a. Oxygen  goes out
b. Carbon dioxide  goes in
c. Water vapor  goes out
2. Guard cells: surround & control  stomata
openings
Section 23-4
Function of Guard Cells
Guard cells
Guard cells
Inner cell wall
Inner cell wall
Stoma
Stoma Open
Stoma Closed
LEAVES cont.
D. TRANSPORT
1. Water escapes through stomata
a. process of  transpiration (evaporation)
b. as water exits, more is drawn up through stem
from roots
2. Stomata open & close to
prevent excessive  water loss.
Section 23-5
Transpiration
A
B
Evaporation of water
molecules out of leaves.
Pull of water molecules upward
from the roots.
Videos
• Water Transport Video
• Phloem Transport Video
Tree Ring Analysis
Tree Ring Pictures from
http://web.utk.edu/~grissino/gallery.htm#Rings
A
A cross section of a small red oak (Quercus rubra) that clearly shows
the tree rings in both the heartwood (darker colored wood in the
center) and sapwood (lighter colored wood towards the outside).
B
2. The blackened
areas indicate
that this tree had
been in a fire.
An incredible set of tree rings on a longleaf pine (Pinus palustris)
section from Lake Louise in southern Georgia. Notice how tight the
ring growth is here. Longleaf pines are very slow-growing and ideal
for reconstructing climate in the coastal plain region of the
Southeastern U.S.
C
4. The scar on the
left side of the
tree indicates that
this tree was
subjected to an
avalanche
A cross section from a white spruce (Picea glauca) that was
struck by a snow avalanche (impact scar on the left side of the
section) in the Canadian Rocky Mountains near Alberta, Canada.
D
1. This tree has the least
amount of rings = It is the
youngest.
3. This tree has about 12
rings = It is about 12 years
old.
5. This tree lived near a
plentiful water source. You
can tell because the thicker
rings indicate weather
conditions that were
favorable for tree growth.
A simple, yet elegant picture of tree rings from a very young
balsam fir (Abies balsamea) This was a person’s Christmas tree.