Download Transport in Living Things

Transport in Living
Things
Chapter 25
Chapter 25.5 Transport
System in Flowering Plants
What did we learn?
Movement of substances
Passive process
Diffusion
Net movement of
Gaseous
molecules
from a
Carbon
region
of higher
dioxide
and
exchange
concentration
oxygen insideto
in of
the
a region
lower
leaves
lungs
concentration
Osmosis
Active process
Active Transport
Net movement of water
molecules from a region of
higher water of
potential
a
Transport
waterto into
region of lower water potential
roots permeable
through a partially
membrane
Movement of
molecules from a
Transport of
region of lower
mineral salts
concentration
to
a region
higher
intoofthe
concentration
roots
with the use of
energy
Lesson Objectives
At the end of the lesson,
You should be able to:
• State what the vascular bundle consists of
• Describe the structure and function of xylem
and phloem
• Identify the position of xylem vessels and
phloem in sections of the stem
• relate the structure and functions of root hairs
to their surface area, and to water and ion
uptake
Looking at the rose…
• How do you turn a white flower into a blue
one?
• How does the coloured water travel up the
stem to the flower?
Vascular tissues
1. Xylem
2. Phloem
Xylem tissue
Structure
•
•
composed of hollow,
nonliving cells (continuous
lumen)
Lignified walls
Function
•
•
transports water and mineral
salts from
roots → stem → leaves
provides mechanical support
to plant
Structure of Xylem
QUESTION
• How is the straw similar to the xylem?
Phloem tissue
Structure
• Living cells
Function
• Transports manufactured
food (sucrose and amino
acids), usually from leaves
→ other parts of the plant
Identifying a vascular bundle
Identifying a vascular bundle in a
dicotyledonous stem
A vascular bundle
cambium
Transverse section of a stem
Why do you think the xylem is
positioned on the inside?
How to distinguish xylem vessels from
phloem in microscopic slides?
Xylem vessels have
• Thicker walls
- due to lignified walls (either annular, spiral
or pitted) to provide mechanical support to
the plant
• Larger lumen compared to phloem
•
Xylem vessels have a darker stain.
Locate the xylem and phloem
phloem
xylem
Leaf structure
xylem
phloem
Transport of water
Structure of root
• Presence of Root hairs
• Increased surface area
Function of root
• Absorb water and
mineral salts from the
surroundings
• Water absorbed from
the root enters the
xylem
Entry of water into the plant
Thin film around particle = dilute
solution of mineral salts
Entry of water from soil
Plasma membrane of
root hair cell
Sap in root hair
Soil solution
Strong solution
of sugars and
salts
Dilute solution
of mineral salts
Low water
potential
H2O
Higher water
potential
Osmosis
Transport of water from
root hair → xylem
High water potential
Low water potential
Transport of mineral salts
Transport of mineral salts
Plasma membrane of
root hair cell
Soil solution
Sap in root hair
Mineral
salts
Mineral
concentration
low
Mineral
concentration
high
Diffusion
Transport of mineral salts
Qn: Can the root hair absorb ions if the
concentration is higher in the root hair sap
compared to the soil solution? Yes!!!
Plasma membrane of
root hair cell
Soil solution
Sap in root hair
Mineral
salts?
Mineral
concentration
high
Mineral
concentration low
Active
transport
Summary
Plant Transport system
Consists of
Xylem
Phloem
transports
Water containing
dissolved mineral
salts from the
roots to the
leaves
where
Water moves
into the root
hair cell via
OSMOSIS
Manufactured
food substances
(eg. sugars) from
the leaves to the
other parts of the
plant
Mineral salts move
into the root hair cell
via Diffusion OR
ACTIVE TRANSPORT
In the next lesson…
We will be learning about
• what is transpiration
• what is translocation
• MINI QUIZ!