Download File - Science at St. Dominics

Section 3.2 Organisation and
the Vascular Structures
Structure of the Flowering Plant
Section 3.2 Organisation and
the Vascular Structures
Organisation of a flowering plant
A flowering plant is
divided into two
portions:
a shoot system
and a root system
Section 3.2 Organisation and
the Vascular Structures
The shoot system
The shoot system is made up of stems, leaves, flowers and buds
Buds
growth tissues – can produce new
stems, leaves and flowers
Flowers
Reproductive organs
Axial buds – grow on side of stem
Apical bud – grows on top of stem
Stem
1. Give support for leaves and flowers
2. transport food and water around the
plant
Leaves
Where photosynthesis takes
place
Section 3.2 Organisation and
the Vascular Structures
The shoot system
Petiole
the stalk of a leaf
Node
The place on the stem that leaves
grow from
Internode
the part of the stem
between two
nodes
Section 3.2 Organisation and
the Vascular Structures
The leaf structure
A leaf with a petiole
A sessile leaf
– no petiole
Section 3.2 Organisation and
the Vascular Structures
Leaf venation
Venation is the pattern of veins on a leaf
Net venation
Section 3.2 Organisation and
the Vascular Structures
The root system
1. The roots anchor the plant in the
soil,
2. absorb water and minerals from
3. may store food
Primary root
The main root that came out of the seed
Secondary root
Roots that come out of the primary root. They have root
hairs which help to absorb water and minerals from the soil
Section 3.2 Organisation and
the Vascular Structures
Vascular tissue
Ground tissue
Dermal tissue
Root hairs
Meristem
Root cap
Root zonations
Zone of differentiation
Elongated cells develop into
different types of tissue –
dermal tissue, ground tissue
or vascular tissue
Zone of elongation
the new cells made grow
longer here
Zone of production
Cells in the meristem of
the root divide by mitosis
to make new cells
Zone of protection
Root cap protects the root cells
as they go into the soil
Section 3.2 Organisation and
the Vascular Structures
The meristem tissue
The meristem tissue produces new cells, which then
become specialised.
• It is found in the shoot and root apices ( tips ) and is
called apical meristem tissue.
Section 3.2 Organisation and
the Vascular Structures
The specialisation of cells
• specialise - change their structure to carry out special jobs in the
plant
• They will become:
Dermal tissue (forms the protective covering of plants)
or
Ground Tissue (fills the inside of the plant)
or
Vascular tissue (transports water and nutrients around the
plant)
Section 3.2 Organisation and
the Vascular Structures
The root
Section 3.2 Organisation and
the Vascular Structures
The root
Dermal Tissue
Ground Tissue
Section 3.2 Organisation and
the Vascular Structures
Tissue location in the root?
Tissue location in the root
Section 3.2 Organisation and
the Vascular Structures
(Longitudinal section)
Section 3.2 Organisation and
the Vascular Structures
The stem
Section 3.2 Organisation and
the Vascular Structures
The root
Tissue location in the root
Section 3.2 Organisation and
the Vascular Structures
(Longitudinal section)
Section 3.2 Organisation and
the Vascular Structures
The stem
Section 3.2 Organisation and
the Vascular Structures
Prepare and examine the
transverse section of a dicot stem
under a microscope
• Cut a section of internodal stem from the celery
using a chopping board
• Carefully cut thin cross sections at a 90o angle
using a wet blade. Cut away from yourself!
• Place cut sections of stem in a Petri dish of
water.
• Make up a microscope slide of the stem piece.
• Examine under the microscope using X100 and
x400 magnifications
• Draw a sketch of the image seen
Section 3.2 Organisation and
the Vascular Structures
Step 1
Collect suitable plant, e.g.celery, geranium. Cut
a short section of the stem between two nodes.
Use a chopping board!
Section 3.2 Organisation and
the Vascular Structures
Step 2
Hold the stem securely and cut several thin
sections at 90° to the stem using a wet blade. Cut
away from fingers.
Section 3.2 Organisation and
the Vascular Structures
Step 3
Place the sections in water. Transfer
to a slide using a paintbrush.
Section 3.2 Organisation and
the Vascular Structures
Step 4
Add a few drops of water and a coverslip at
an angle. Observe under the microscope.
Section 3.2 Organisation and
the Vascular Structures
Expected result
Tissue location in stem?( Longitudinal
Section 3.2 Organisation and
the Vascular Structures
section)
Section 3.2 Organisation and
the Vascular Structures
Section 3.2 Organisation and
the Vascular Structures
Return to
procedur
e
Section 3.2 Organisation and
the Vascular Structures
Experiment Questions
TS Dicot Stem
Section 3.2 Organisation and
the Vascular Structures
The Leaf
Ground Tissue
Dermal Tissue
Vascular Tissue
Found in the centre
of the leaf .
Section 3.2 Organisation and
the Vascular Structures
Tissue Location in the Leaf
Dermal
Tissue
Ground
Tissue
Vascular
Tissue
Dermal Tissue
Section 3.2 Organisation and
the Vascular Structures
The Leaf
Section 3.2 Organisation and
the Vascular Structures
Vascular Tissue
• Vascular Tissue transports materials around the plant
• It is made up of xylem and phloem tissue
Section 3.2 Organisation and
the Vascular Structures
Xylem
Xylem tissue is used to transport
water around the plant and to
support it
There are two types of xylem cells
tracheid cells and vessel cells
Both cells have no cytoplasm and
both have lignin in their cell walls,
which strengthens them
Section 3.2 Organisation and
the Vascular Structures
Movement between xylem cells
Xylem Tracheids
Found in conifers
Xylem Vessels
Found in deciduous trees
Section 3.2 Organisation and
the Vascular Structures
Xylem tissue
Tracheid cells have narrow ends
with holes in their walls called
pits.
Vessel cells are larger cells with
no end wall to allow water to
flow uninterrupted from one
vessel cell to the next
Section 3.2 Organisation and
the Vascular Structures
Phloem tissue
Phloem tissue is used to transport nutrients and sugars around the
plant
There are two types of phloem cells: Sieve tube element cells and
companion cells
Companion cells
Section 3.2 Organisation and
the Vascular Structures
Companion cells
• have
a nucleus which
controls both cells
•Are in control of the
movement of materials in the
sieve plates.
Sieve Tube element cells
•long and thin cells with no
nucleus.
•They have holes in their
end walls which are called
“sieve plates”
Section 3.2 Organisation and
the Vascular Structures
Flowering Plants
Two classes:
monocotyledons “monocots”
and
dicotyledons “dicots”
Section 3.2 Organisation and
the Vascular Structures
Monocots
Have a single cotyledon
( a leaf inside the seed where food is stored)
Leaves have parallel venation
They have scattered vascular bundles
They have flowers arranged in groups of three
They are usually soft plants, with no woody parts
“Herbaceous”
Section 3.2 Organisation and
the Vascular Structures
Dicots
Have two cotyledons
Leaves have net venation
They have vascular bundles arranged in a ring
They have flowers arranged in groups of four or five
They can be Herbaceous or woody