Download Transport in Plant

Transport in
Plant
Water transport
Food transport
Water Transport
Root Pressure
Capillary action
Transpiration
Root pressure
Water is drawn in root by osmosis.
Excess water is pushed into xylem by
pressure. This pressure push water up
in xylem.
Capillary Action
Since the adhesive force
between water molecules and
tube materials is larger than
cohesive force between water
molecules, water column is
pulled up by adhesive force.
Transpiration
Stomata opened by guard cells.
Water diffuse out through stomata.
Water evaporate from cell wall to intercellular space.
Water draw to surface cell from xylem by osmosis.
Unbreakable water column pull up by leave.
Water draw into xylem from root cell by pull.
Water draw from soil to root cells.
Glucose
increase
Stomata
Water diffuse out
Symplast, apoplast
Diffusion evaporation
Xylem
Tracheid
Photo
In root
In Root
Water pathway
Casparian strip
Mature endodermis
Photo of young root
Model of transpiration
Potometer
Not for rate of transpiration but for water
absorption only. How can transpiration
rate be determinated.
Plant in dry region
Increase water absorption
Decrease water evaporation
Transport of food in
Phloem
Criteria
Energy required
Occurred in sieve tubes
Direction from leave to organs
Up and down possible
Structure of phloem
Mass flow hypothesis
i. Sucrose move to phloem from leave cell by active transport.
ii. Water potential in phloem decrease.
iii. Water move in phloem by osmosis.
iv. Water volume increase in phloem, turgid pressure increase.
v. Sucrose remove from phloem at organ by active transport.
vi. Water potential in phloem increase.
vii. Water move out of phloem by osmosis. Pressure decrease.
viii. Water flow by pressure difference.
ix. Sucrose flow with water along phloem.
Model of translocation
Experiment