Transport in Transport in PlantPlant

Water transport

Food Food transporttransport

Water TransportWater Transport

Root PressureCapillary actionTranspiration

Root pressureRoot pressure

Water is drawn in root by osmosis. Excess water is pushed into xylem by pressure. This pressure push water up in xylem.

Capillary ActionCapillary ActionSince 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.

TranspirationTranspirationStomata 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.

StomataStomataGlucose increase

Water diffuse outWater diffuse outSymplast, apoplast

Diffusion evaporation

Xylem Xylem

TracheidTracheid

Photo Photo

In root In root

In RootIn Root

Water pathwayWater pathway

Casparian stripCasparian strip

Mature endodermisMature endodermis

Photo of young Photo of young rootroot

Model of Model of transpirationtranspiration

Potometer Potometer Not for rate of transpiration but for water absorption only. How can transpiration rate be determi

nated.

Plant in dry regionPlant in dry regionIncrease water absorption

Decrease water evaporation

Transport of food Transport of food in Phloem in Phloem

CriteriaEnergy requiredOccurred in sieve tubesDirection from leave to

organsUp and down possible

Structure of Structure of phloemphloem

Mass flow Mass flow hypothesishypothesisi. 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 Model of translocationtranslocation

Experiment Experiment