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Transport in Plants - Coggle Diagram
Transport in Plants
Why have a transport system?
Low SA:V ratio
Large size means transport needs to be quick
High metabolic rate is needed for photosynthesis and respiration.
Diffusion not fast enough
Seeds
Contain two cotyledons which act as food stores for the plant embryo
Leaves form in germination
Xylem
Non-living tissue transporting water and minerals
Lined with lignin spirals, rings and pits
Bordered pits allow water to leave
Parenchyma surround storing food and tannin
Phloem
Living tissue which transports assimilates.
Flow goes up and down
Sieve tube elements and companion cells
Sieve plates
Plasmodesmata
Translocation
Sources to sinks
Unloading/loading
H+ ions pumped and are cotransporter back with sucrose
Diffuses into sieve tube elements
Water moves by osmosis
Mass flow
Turgor
Transpiration
Water moves up xylem
Water moves by symplast pathway by osmosis.
Water moves by capillary action
Guard cells have inflexible inner walls.
Affected by light intensity, humidity, temperature and air movement
Potometer
Cut shoot at a slant underwater to raise SA
Don't introduce air bubble
Seal joints using Vaseline
Rate can be measured
Transport
Why is water key?
Turgor pressure
tranpiration
Transport of mineral ions and assimilates
Water needed for photosynthesis
Root Hair Cells
Specialised cells
Large SA:V ratio
High conc. of solutes
Low water potential
Water Pathways
Symplast
Moves through cytoplasm
Connected by plasmodesmata by osmosis
Apoplast pathway moves through cell walls and intercellular spaces
Moves through cohesion tension
Casparian strip made of suberin creates a waterproof layer
Minerals AT into xylem moving water by osmosis
Plant Adaptations
Xerophytes
Smaller leaves
Rolled leaves
Fewer of leaves
Hairy leaves
Thick waxy cuticle
Hydrophytes
No waxy cuticle
Open stomata
Wide flat leaves
Aerenchyma