Transport in plants

Transport mechanisms –Passive transport –Active transport Osmotic active transport Osmotic active transport Non osmotic active transport Non osmotic active transport

Plant transport… What substances move throughout a plant? What substances move throughout a plant? –Where does water go? –Where does sugar go? –Where to inorganic nutrients (minerals) go? –Where do gasses go? (ie. O 2 /CO 2 ) –Where do secundary organic molecules go?

Fig. 39.8

Water movement Where does water move within a plant? Where does water move within a plant? How does water move at the cellular level? How does water move at the cellular level? –Remember osmosis? –What is water potential? Balancing osmosis Balancing osmosis

Water movement What is solute potential (ψ S )? What is solute potential (ψ S )? –Is ψ S positive or negative? What is pressure potential (ψ P )? What is pressure potential (ψ P )? –Is ψ P positive or negative? What is WATER POTENTIAL (ψ)? What is WATER POTENTIAL (ψ)? –ψ S + ψ P –Pure water has no water potential Ψ water = 0 Ψ water = 0

Water transport in roots How does water enter roots? How does water enter roots? –Remember root hairs –What is the apoplastic route? –What is the symplastic route? –What is the casparian strip? Remember subarin? Remember subarin? –How does mineral transport help?

Fig (Apoplastic) (Symplastic)

Water transport in shoots How does water move up the plant? How does water move up the plant? –What is root pressure? –What is guttation? –When does this occur?

More water transport in shoots What is transpiration? What is transpiration? –Where is most water lost from plants? Remember stomata? Remember stomata? –How does transpiration affect water potential in xylem? What happens to ψ S ? What happens to ψ S ? What happens to ψ p ? What happens to ψ p ? Remember…XYLEM SUCKS!!! Remember…XYLEM SUCKS!!!

Fig

Controlling transpiration How do stomata open? How do stomata open? –The inner tube story… –How are guard cell walls specialized? –What happens when guard cells expand? –How do guard cells expand Where salt goes, water follows! Where salt goes, water follows! Remember abscisic acid? Remember abscisic acid?

Sugar movement in plants Where are sugars produced? Where are sugars produced? –What is the source? Where do sugars go? Where do sugars go? –What is the sink? –Where are sugars needed? –How do they get there? Remember phloem Remember phloem

Fig a

Sugar movement in phloem How do sugars get into phloem? How do sugars get into phloem? –What is the concentration gradient for sucrose entering sieve tubes? –Where does energy for transport come from? Remember respiration Remember respiration

Fig b

Back to the sugar… What are the biologically relevant forms of energy? What are the biologically relevant forms of energy? –Light energy –Electrical energy –Chemical –Concentration gradients

Plant productivity 720 billion tonnes of global carbon every year 10% is sugar 10% is sugar % is CO % is CO2 Where does the sugar come from Where does the sugar come from

More productivity Where does energy for photosynthesis come from? Where does energy for photosynthesis come from? –The power of light… –Where is the trick Remember pigments Remember pigments Where do the raw materials come from? Where do the raw materials come from? –Remember CO 2, H 2 O

Photosynthesis (C3) What is the overall scheme What is the overall scheme –Gathering energy –Converting light  usable energy Photophosphorylation Photophosphorylation Making ATP, stored electrons Making ATP, stored electrons –Using stored energy to  sugar Calvin cycle Calvin cycle Biochemical baby steps Biochemical baby steps Built on THREE CARBON intermediates Built on THREE CARBON intermediates