Transport in Living
Things
Chapter 25
Chapter 25.5 Transport
System in Flowering Plants
What did we learn?
Transport
system of
plants
Consists
of
Is a living tissue
made up of sieve
tubes and
companion cells
Phloem
Xylem
Water
enters
Transports
food
substances
roots
via
osmosis
Is a continuous
hollow tube with
lignified walls
Transports
water and
mineral salts
Lesson Objectives
At the end of the lesson,
You should be able to:
• relate the structure and functions of root hairs
to their surface area, and to water and ion
uptake
• state that transpiration is the loss of water
vapour from the stomata
• define the term translocation as the transport
of food in the phloem tissue
Transport of mineral salts
Plant Profile
What process is being used to
take in mineral salts?
Name: Claudia
Owner: Farmer A
Characteristics: Is
watered and
fertilizer is added
everyday.
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
Plant Profile
What process is being used to
take in mineral salts?
Name: Lydia
Owner: No one
Characteristics: No
one takes care of it
and the soil is dry
and mineral- poor.
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
Translocation
Definition:
It is the transport of manufactured food
substances such as sugars and amino acids in
plants.
How can we show that the phloem carries
materials from the leaves to other parts of the
plant?
“Ringing” experiment
1) Take the branch of a woody plant
2) Remove a ring of bark from around the main
stem.
3) Put it into water
4) Observe it over a few weeks
“Ringing” experiment
A
B
Region with
bark removed
Water
Unringed
twig
After a few weeks…
• The part of the
stem just above
the cut region
will swell
Transpiration
Definition of transpiration:
The loss of water vapour from the aerial parts
of the plant, especially through the stomata of
the leaves
Similarity?
Functions of transpiration:
1.
Cool the plant; prevent scorching
2.
Facilitates the lifting of water and mineral salts
from roots to leaves
Transpiration pull
Evaporation of
water from
leaves
Leaf
cells
lose
water
Cells remove water
from xylem vessels
concentrated cell sap =
lower water potential
Creates a
transpiration
pull
Draw water from cells
deeper inside the leaf
by osmosis
The evaporation of water from leaves result in a suction force
which pulls water up the xylem vessels
Suction force due to transpiration is transpiration pull
Factors affecting transpiration rate
1.
2.
3.
4.
5.
Humidity of air
Temperature of air
Strong wind
Light
Size and shape of leaves (surface area)
Summary
Water
Diffuses
out of
Leaves or
aerial
parts of
the plant
enters
Mineral salts
enters
roots
Osmosis
Travels from
roots
via
via
Food
substances
via
Diffusion
Transpiration
Is the loss of
water vapour from
the aerial parts of
the plant
leaf
to
Other
Active
parts ofof
Is the transport
transport
manufactured
food
the plant
substances such as
viaand amino
sugars
acids in the plants
Translocation