plant transport chapter 36. plant transport evolutionary changes roots, leaves, stems water...
TRANSCRIPT
Plant transport
Chapter 36
Plant transport
Evolutionary changesRoots, Leaves, StemsWaterCarbohydratesMineralsLight energyCO2
O2
Water transport
RootsXylemStomataTranspiration Cohesion & adhesion
Water transport
Flaccid:LimpWater lossPlasmolysis:Cell membrane pulls away from cell wallDue to water loss
Water transport
Turgid: FirmWater gainHealthier plant
Water transport
Cell to cell (short distance)Diffusion Apolplast:Continuum formed by cell wallsSymplast:Continuum formed by cytoplasm of cellsPlasmodesmata:Connection between cytoplasm
Cell wall
Cytosol
Apoplastic route
Symplastic route
Transmembrane route
Plasmodesma
Plasma membrane
Key
Apoplast
Symplast
Water transport
Root hairs absorb water & mineralsDiffuse into apoplast or symplastPass through cortexEndodermis (inner lining of cortex)Casparian strip (waxy substance)Controls flow water/ions to xylem Forces flow to pass cell membrane
Casparian strip
Plasmamembrane
Apoplasticroute
Symplasticroute
Roothair
Epidermis
Cortex
Endodermis
Vessels(xylem)
Stele(vascularcylinder)
Xylem
Movement based on bulk transportTranspiration:Negative pressureRoot pressure: Positive pressureUpward push of water/ions in xylemSolar powered
Xylem
Guttation:Loss of liquid through leavesEnds of leaves Increased root pressure
Stomata
H2O loss
CO2 intake
Guard cells
Opening & closing of the stomataDependent on turgor pressure of guard cellsThicker inner cell layerCauses bowing of the cell when turgidOpens the stomata
Guard cells
Active K+ pumpIncreased K+ in the guard cellsIncrease in H2O in the guard cells
TurgidStomata opensDecreased K+ leads to decreased H2O
Flaccid, stomata closes
Translocation of Phloem Sap in Spring
Translocation of Phloem Sap in Summer
Carbohydrate movement
Phloem (sieve-tube)Moves from source to nearest sinkCarbohydrates enter sieve-tube cellsActive transportCompanion cells & parenchyma cells provide the ATP
Phloem
Carbohydrate movement
Water potential differences-createdWater moves into the sieve-tube cells (osmosis)Increased turgorMoves carbohydrates to sink
Carbohydrate movement
Carbohydrates removed Active transportWater moves out (osmosis)Water diffuses back to xylemOr lost in transpiration