Transcript Phloem Structure

Structure of Flowering Plants
You need to know details on…
1.
Structure & function of root and shoot systems
2.
Root zonations and all outer stem parts
3.
Meristem function / location in root & shoot
4.
Location of 3 tissue types in transverse and
long sections of root and stem
5.
Xylem & Phloem structure and function
6.
Distinguish between Moncots and Dicots
7.
Mandatory Activity….TS Dicot stem
Objectives
1 Label a diagram of the external parts of a
typical flowering plant
Shoot, root, stem, leaves, flower, fruit, seed.
2 State the function of the root and shoot
3 Identify tap and fibrous root systems
4 Explain the term Meristem and give its
location in the stem and root
5 Name and give the function of four zones in a
longitudinal section of a root
6 State the function of Vascular Tissue
7 Give the location of three tissue types,
Dermal, Ground and Vascular, in transverse
sections of the of the root and stem and leaf
8 Give the location of three tissue types,
Dermal, Ground and Vascular, in
longitudinal sections of the root and stem.
9 Identify and draw the structure of Xylem and
Phloem and state their function
10 Distinguish between Xylem Vessels and
Xylem tracheids, and between Phloem
Sieve Tube Cells and Companion Cells
11. Identify Monocots and Dicots under the
Headings:
Number of flower parts
Vein pattern in leaf
Arrangement of Vascular Bundles
Number of Cotyledons in the seed
Woody or Herbaceous
12. Mandatory Practical:
Prepare and examine a transverse section of a Dicot stem
under the microscope
What Flowering Plant typically have:
1.
Transport (Vascular) Structures
2.
Roots
3.
Stems
4.
Leafs
5.
Flowers
6.
Fruits & Seeds
External Structure of Flowering Plants
Over ground shoot
system
Under ground
root system
Label Diagram of
flowering plant
Root Types
1. Tap Roots
One main root growing
from the radicle
eg Carrot
2. Fibrous Roots
Many equal sized roots arising from
stem base
eg grass
3. Adventitious Roots
Roots that do not develop from the
radicle. E.g. gripping roots of ivy.
Root Functions
1. Anchor plant
in the ground
2. Absorb Water
3. Absorb minerals
4. Transport absorbed materials to
shoot
5. Store food
Meristem
An area of active cell division
Apical meristems are found
at the tip of the shoot and
tip of the root and give an
increase in length
Lateral meristems are
found around the edges of
some plants and give an
ìncrease in width
Four Root Zones
Differentiation Zone
Elongation Zone
Meristematic Zone
Protection Zone
Root Zones
Differentiation Zone
Here cells develop
into 3 different
types of tissue
1. Dermal tissue
2. Ground Tissue
3. Vascular tissue
Root Zones
Elongation Zone
Here cells increase in
size
Root Zones
Meristematic Zone
Here new cells are
produced by mitosis
divisions
Root Zones
Protection Zone
A root cap protects
the cells as the root
pushes through the
soil
Quiz
1.
Name the two types of root system
2.
Explain the term Meristem
3.
Name the four zones in a root
4.
What is the function of the root cap ?
Tissue location in the root
(transverse section)
Dermal Tissue
Xylem
Vascular
Tissue
Phloem
Ground
Tissue
Tissue location in the root
(transverse section)
Dermal Tissue
Xylem
Vascular
Tissue
Phloem
Ground
Tissue
Tissue location in the root
(transverse section)
(Center part of root)
Xylem
Vascular
Tissue
Phloem
Ground
Tissue
Tissue location in the root
(Longitudinal section)
Dermal Tissue
Ground Tissue
Vascular Tissue
Ground Tissue
Dermal Tissue
Stem Functions
1. Support the arial
parts of the plant
2. Transport water and
minerals from roots to
leafs
3. Transport food from
leafs to roots
4. Sometimes store food
Function of outer stem parts
Terminal Bud
Increase stem length
Lateral Bud
Grow side branches
Lenticels
Gas exchange
A= Terminal Bud
B= Leaf Scar
C= Scale Scar
D= Lateral Bud
Year
3
Year
2
Year
1
Lenticels
Tissue location in stem
(Transverse section)
Dermal Tissue
Xylem
Vascular
Tissue
Phloem
Ground
Tissue
Tissue location in stem
( Longitudinal section)
Dermal
Ground
Vascular
Ground
Vascular
Ground
Dermal
Learning Check 2 ….. Label the diagram
Leaf parts
• Some leaves do
not have a petiole
(They are called
sessile leaves)
• Veins contain the
vascular tissue
Leaf Functions
1. Photosynthesis
2. Transpiration
3. Gas exchange
4. Sometimes store food
Tissue Location in the Leaf
Dermal
Tissue
Ground
Tissue
Vascular
Tissue
Dermal Tissue
Flower Function
Sexual
Reproduction
Vascular Tissue
1.
Xylem
Function
2.
Transport water
Transport minerals
Phloem
Function
Transport food
Xylem Structure….Two types of Cell
Xylem Tracheids
Xylem Vessels
On maturity both
are dead, hollow
and contain no
cytoplasm
Found in conifers
Found in deciduous trees
Xylem Tracheid Structure
Long cells tapered at both ends
Pits in the walls – allow water
and minerals to move
sideways from cell to cell
Walls thickened with
lignin for support
Xylem Vessels Structure
Elongated cells
Spiral lignin for
strength
No end walls – form a
continuous tube
Pits to allow sideways
movement of water
Phloem Structure
2 Companion
Cells
1. Sieve tube
cells
Mature cells
have no
nucleus
Sieve plates
Nucleus controls
activities of
both companion
and sieve tube
cell
Cytoplasm extends
from cell to cell
through the
sieve plate
Phloem
Longitudinal and Transverse sections
Example of Monocot and Dicot
Monocot
Grass
Dicot
Buttercup
Differences between Monocots & Dicots
Monocotyledons
Number of
cotyledons
Arrangement of
vascular
bundles in the
stem
One
Scattered in the
stem
Leaf venation
Parallel
Number of
flower parts
In threes
Woody or
herbaceous
Almost all are
herbaceous
Dicotyledons
Two
In a ring pattern
Netted
In fours and fives
May be woody or
herbaceous
Identification of Monocots & Dicots
Learning Check 3
1.
State two functions of a leaf
2.
Distinguish between xylem vessels and
xylem tracheids
3.
What is the role of the companion cell in
phloem tissue
4.
How is a transverse section of a monocot
stem different to the TS od a Dicot stem ?
End