Transport in Plants
Contents
Transport System of Flowering plants
What is Xylem?
What is Phloem?
Structure of Xylem
Structure of Phloem
Ion Uptake
Transport system of
flowering plants
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The vessels that transport materials in
plants is known as the vascular tissue.
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There are two main transport tissues:
 Xylem
 Phloem
What is Xylem?
• Xylem is a plant vascular tissue that
conveys water and dissolved minerals
from the roots to the rest of the plant
and also provides physical support.
• Together with phloem , xylem is found
in all vascular plants, including the
seedless plants: ferns, horsetails, as
well as all flowering plants .
What is Phloem?
Phloem is the vascular tissue in charge of transport
and distribution of the organic nutrients ,in particular
the sugar sucrose. The phloem is also a pathway to
signaling molecules and has a structural function in
the plant body.
Vascular Tissue
• The primary components of vascular tissue are the
xylem and phloem. These two tissues transport fluid and
nutrients internally.
• The two are separated by the CAMBIUM.
• The cambium divides and differentiates to
form new xylem and phloem tissues.
Structure of Xylem
• Xylem tissue consists mainly of Xylem
Vessels.
• A xylem vessel is a long hollow tube
made of many dead cells.
• Inner walls are strengthened by lignin rings or spirals.
Stages of cell
division
Structure of
Consists
of two elements:
Phloem
sieve tube and companion cells.
 Sieve tube cells or sieve tube elements
 Elongated, thin walled LIVING cells
 Cells separated by sieve plates
 Cross walls that are perforated with pores = sieve
 Sucrose is loaded into the sieve tube by active
transport.
Phloem consists of:
Sieve Tube cells
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Mature sieve-tubes has thin
lining of cytoplasm.
Nucleus, central vacuole as well
as most organelles are
disintegrated.
Degenerated protoplasm
Sieve tube cells need help to
sustain life
Companion cells ‘accompany’
them and ‘feed’ them.
Companion Cells
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Each sieve tube cell has a
companion cell beside it
This carries out the metabolic
processes to keep both cells
alive
Structure:
narrow,thin-walled,many
mitochondria. Has cytoplasm
and a nucleus
Function:
Provides nutrients and helps
sieve tube cells transport food.
Stages of cell
division
Ion Uptake
•
Plants absorb water from the soil by osmosis. They absorb mineral
ions by active transport, against the concentration gradient. Root hair
cells are adapted for taking up water and mineral ions by having a
large surface area to increase the rate of absorption.
•
They also contain lots of mitochondria, which release energy from
glucose during respiration in order to provide the energy needed for
active transport.
Purposes of Absorbed Nutrients
The absorbed water is transported through the roots to the rest of the plant where it is used for different
:
purposes
It is a reactant used in photosynthesis.
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It supports leaves and shoots by
keeping the cells rigid.
It cools the leaves by evaporation.
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It transports dissolved
minerals around the plant.
Stages of cell
division