Transport in plantsTransport in plants

Transport mechanismsTransport mechanisms

– Passive transportPassive transport– Active transportActive transport

•Osmotic active transportOsmotic active transport

•Non osmotic active transportNon osmotic active transport

Plant transport…Plant transport…

• What substances move throughout a What substances move throughout a plant?plant?– Where does water go?Where does water go?– Where does sugar go?Where does sugar go?– Where to inorganic nutrients (minerals) go?Where to inorganic nutrients (minerals) go?

– Where do gasses go? (ie. OWhere do gasses go? (ie. O22/CO/CO22))

– Where do secundary organic molecules go?Where do secundary organic molecules go?

Fig. 39.8

Water movementWater movement

• Where does water move within a Where does water move within a plant?plant?

• How does water move at the cellular How does water move at the cellular level?level?– Remember osmosis?Remember osmosis?– What is water potential?What is water potential?

•Balancing osmosisBalancing osmosis

Water movementWater movement

• What is solute potential (What is solute potential (ψψSS)?)?

– Is Is ψψSS positive or negative? positive or negative?

• What is pressure potential (What is pressure potential (ψψPP)?)?

– Is Is ψψPP positive or negative? positive or negative?

• What is WATER POTENTIAL (What is WATER POTENTIAL (ψψ)?)?– ψψSS + + ψψPP

– Pure water has no water potentialPure water has no water potential•ΨΨwaterwater = 0 = 0

Water transport in rootsWater transport in roots

• How does water enter roots?How does water enter roots?– Remember root hairsRemember root hairs– What is the apoplastic route?What is the apoplastic route?– What is the symplastic route?What is the symplastic route?– What is the casparian strip?What is the casparian strip?

•Remember subarin?Remember subarin?

– How does mineral transport help?How does mineral transport help?

Fig. 39.9

(Apoplastic)

(Symplastic)

Water transport in shootsWater transport in shoots

• How does water How does water move up the move up the plant?plant?– What is root What is root

pressure?pressure?– What is What is

guttation?guttation?– When does this When does this

occur?occur?

More water transport in shootsMore water transport in shoots

• What is transpiration?What is transpiration?– Where is most water lost from plants?Where is most water lost from plants?

•Remember stomata?Remember stomata?

– How does transpiration affect water How does transpiration affect water potential in xylem?potential in xylem?•What happens to What happens to ψψSS??

•What happens to What happens to ψψpp??

• Remember…XYLEM SUCKS!!!Remember…XYLEM SUCKS!!!

Fig. 39.10

Controlling transpirationControlling transpiration

• How do stomata open?How do stomata open?– The inner tube story…The inner tube story…– How are guard cell walls specialized?How are guard cell walls specialized?– What happens when guard cells What happens when guard cells

expand?expand?– How do guard cells expandHow do guard cells expand

•Where salt goes, water follows!Where salt goes, water follows!

•Remember abscisic acid?Remember abscisic acid?

Sugar movement in plantsSugar movement in plants

• Where are sugars produced?Where are sugars produced?– What is the source?What is the source?

• Where do sugars go?Where do sugars go?– What is the sink?What is the sink?– Where are sugars needed?Where are sugars needed?– How do they get there?How do they get there?

•Remember phloemRemember phloem

Fig. 39.17a

Sugar movement in phloemSugar movement in phloem

• How do sugars get into phloem?How do sugars get into phloem?– What is the concentration gradient for What is the concentration gradient for

sucrose entering sieve tubes?sucrose entering sieve tubes?– Where does energy for transport come Where does energy for transport come

from?from?•Remember respirationRemember respiration

Fig. 39.17b

Back to the sugar…Back to the sugar…

• What are the biologically relevant What are the biologically relevant forms of energy?forms of energy?– Light energyLight energy– Electrical energy Electrical energy – ChemicalChemical– Concentration gradientsConcentration gradients

Plant productivityPlant productivity720 billion tonnes of global carbon every 720 billion tonnes of global carbon every

yearyear•10% is sugar10% is sugar

•0.0001% is CO20.0001% is CO2

•Where does the sugar come fromWhere does the sugar come from

More productivityMore productivity

• Where does energy for Where does energy for photosynthesis come from?photosynthesis come from?– The power of light…The power of light…– Where is the trickWhere is the trick

•Remember pigmentsRemember pigments

• Where do the raw materials come Where do the raw materials come from?from?– Remember CORemember CO22, H, H22OO

Photosynthesis (C3)Photosynthesis (C3)

• What is the overall schemeWhat is the overall scheme– Gathering energyGathering energy– Converting light Converting light usable energy usable energy

•PhotophosphorylationPhotophosphorylation

•Making ATP, stored electronsMaking ATP, stored electrons

– Using stored energy to Using stored energy to sugar sugar•Calvin cycleCalvin cycle

•Biochemical baby stepsBiochemical baby steps

•Built on THREE CARBON intermediatesBuilt on THREE CARBON intermediates