Trasport in plants ppt

Transportation in Plants for class X Biology

2. Why plants need transport
system
•By using the CO
2
energy ( food ) is produced in the
leaves
•The soil is the nearest & richest source of raw
materials like nitrogen, phophorous & other minerals
•The absorption of these substances occurs through
the part in contact with the soil, called roots if these
distances between soil containing regions &
chlorophyll containing regions are small energy &
raw materials can easily diffuse to all parts of the
plant body
•If these distances are large the diffusion pressure
will not be sufficient to provide raw materials in
leaves & energy in roots

3. Why plants have low energy
needs
•1. Plants do not move
•2.Plant bodies have large proportion of

dead cells in many tissues
As a result plants have low energy
needs & use low transport system

4. Plant transport systems
•There are two transport systems
•1. One transport system moves water &
minerals from roots to leaves through
the xylem
•1. Another transport system moves
energy stores ( food ) from leaves to
body parts
•

6. TRANSPORT OF WATER
•It takes place through the Xylem
•Vessels & Tracheids are the water
conducting cells in the xylem
•In xylem tissue vessels & trachieds of
the roots , stem, leaves are
interconnected to form a continuous
system of a water conducting channels
reaching all parts of the plant

8. Mechanism of water conduction
•It is explaind by many theories.
Important theories among these are
•1. Root pressure theory
•2. transpiration pull theory

9. Root pressure theory
•At the roots cells in contact wit the soil
actively take up the mineral ions
•This creates a difference in the
concentration of these ions between the
roots & the soil
•Therefore water moves from the soil into the
cells to eliminate this difference
•So there is a steady movement of water into
root xylem, creating a column of water that is
steadily pushed upwards this is due to the
creation of pressure in the xylem vessels of
the root

10. Demerits of root pressure theory
•This pressure is not sufficient to push
the water to the great heights

18. Transpiration pull theory
•Plants lose water in the form of water vapour
through the stomata of the leaf
•This water loss is replaced by the by the
xylem vessels in the leaf
•Evaporation of water from the cells of the
leaf creates a suction which pulls water from
the xylem vessels of the root
•It makes the root to absorb water from the
soil

19. •The root pressure is the major driving
force during the night time
•During the day when the stomata are
open , the transpiration pull is the
major driving force

20. Transpiration
•The loss of water in the form of water
vapour from the aerial parts of the plant
is called transpiration

21. Functions of transpiration
•1. It helps in temperature regulation
•2. It helps in absorption& upward
movement of the water minerals
dissolved in it from roots to the leaves

22. Transport of food & other
substances
•The transport of soluble products of
photosynthesis from leaves to all parts of the
plant is called translocation
•Phloem transports the food
•Besides the products of photosynthesis the
phloem also transports amino acids & other
substances
• These substances are moved to the storage
organs of the roots, fruits, seeds & to
growing regions

23. In phloem the food
conducting cells are
the sieve tubes
The translocation of
food & other
substances takes
place in the sieve
tubes with the help of
adjacent companion
cells both in upward
& downward direction

24. Mechanism of translocation
•Translocation utilizes the energy
•Sucrose is transferred into phloem
using energy from ATP
•This increases the osmotic pressure of
the phloem causing water to move from
xylem to phloem
•This pressure moves the materials in
the phloem to tissues which have less
pressure
•This allows the phloem to move the
materials according to the plant needs
•Ex- in the spring sugar stored in roots
or stem transported to the buds which
need energy to grow
•Translocation takes place both in
upward & down ward directions

28. Differences between conduction
of water & conduction of food
Conduction of water conduction of food
1. It occurs through the It occurs through the
xylem phloem
2. It does not utilize It utilizes energy
energy.
3. It is in upward It is both in upward
direction downward direction