1. Stress responses/stress avoidance
Plan C
We will pick a problem in plant biology and see where it takes us.
Plant products
Climate/CO2 change
Stress responses/stress avoidance

2. Plants & products chosen
Capsaicin
Capsicum sp.
Glucosinolates
Radishes (Raphanus sativus)
Mustard (Brassica juncea)
Alliin -> Allicin
Garlic (Allium sativum)

3. Other candidates
Propanethial-S-oxide
Onions (Allium cepa)
Portulacanones
Purslane (Portulaca oleracea)
Allyl isothiocyanate
Horseradish (Armoracia rusticana)
Wasabi (Eutrema japonicum)
eugenol (and others)
Basil (Ocimum basilicum)

4. Stresses Chosen
Climate change
Temperature
Increased pCO2
Drought pH
Nutrient deprivation
Metal toxicity (a result of low pH)
Predation
Shaking

5. Course Plan
We will study effects of nutrition and stresses on plant growth and secondary products and see where it leads us
Learn about plant stress
Learn about plant nutrition
Learn about plant secondary products
Pick plants to study
Decide how to study them

6. Plant Stress
Won Senator Proxmire’s “Golden Fleece” award for wasteful government spending
Water?
Nutrients?
Environment?
Temp?
Pollution?
Ozone, other gases?
Herbicides, eg Round-Up, Atrazine?
Insects and other herbivores?
Pathogens = bacteria, viruses, fungi

7. Mineral Nutrition
Studied by soil-free culture in nutrient solutions:
Sand culture
Hydroponics: immerse roots in nutrient solution
Slanted film maintains [nutrients] & O2
Aeroponics sprays nutrient solution on roots

8. Mineral Nutrition
Macronutrients: CHOPKNSCaFeMg
Micronutrients: BNaCl others include Cu, Zn, Mn

9. Mineral Nutrition
Soil nutrients
Amounts & availability vary
Many are immobile, eg P, Fe

10. Mineral Nutrition
Ectomycorrhizae surround root: only trees, esp. conifers
release nutrients into apoplast to be taken up by roots

11. Rhizosphere
Endomycorrhizae invade root cells: Vesicular/Arbuscular
Most angiosperms, especially in nutrient-poor soils
Deliver nutrients into symplast or release them when arbuscule dies
Also find bacteria, actinomycetes, protozoa associated with root surface = rhizosphere

12. Rhizosphere
N-fixing bacteria supply N to many plant spp
Most live in root nodules & are fed & protected from O2 by plant

13. Nutrient uptake
Then must cross plasma membrane
Gases, small uncharged & non-polar molecules diffuse
down their ∆ [ ]
Important for CO2, auxin & NH3 transport

14. Nutrient uptake
Then must cross plasma membrane
Gases, small uncharged & non-polar molecules diffuse
down their ∆ [ ]
Polar chems must go through proteins!

15. Selective Transport
1) Channels
integral membrane proteins with pore that specific ions diffuse through

16. Selective Transport
1) Channels
integral membrane proteins with pore that specific ions diffuse through
depends on size
& charge

17. Channels
integral membrane proteins with pore
that specific ions diffuse through
depends on size & charge
O in selectivity filter bind
ion (replace H2O)

18. Channels
integral membrane proteins with pore
that specific ions diffuse through
depends on size & charge
O in selectivity filter bind
ion (replace H2O)
only right one fits

19. Channels
O in selectivity filter bind
ion (replace H2O)
only right one fits
driving force?
electrochemical D

20. Channels
driving force : electrochemical D
“non-saturable”

21. Channels
driving force : electrochemical D
“non-saturable”
regulate by opening & closing

22. Channels
regulate by opening & closing
ligand-gated channels open/close when bind specific chemicals

23. Channels
ligand-gated channels open/close when bind specific chemicals
Stress-activated channels open/close in response to mechanical stimulation

24. Channels
Stress-activated channels open/close in response to mechanical stimulation
voltage-gated channels open/close in response to changes in electrical potential

25. Channels
Old model: S4 slides up/down
Paddle model: S4 rotates

26. Channels
Old model: S4 slides up/down
Paddle model: S4 rotates
3 states
Closed
Open
Inactivated

27. Selective Transport
1) Channels
2) Facilitated Diffusion (carriers)
Carrier binds molecule

28. Selective Transport
Facilitated Diffusion (carriers)
Carrier binds molecule
carries it through membrane
& releases it inside

29. Selective Transport
Facilitated Diffusion (carriers)
Carrier binds molecule
carries it through membrane
& releases it inside
driving force = ∆ [ ]

30. Selective Transport
Facilitated Diffusion (carriers)
Carrier binds molecule
carries it through membrane
& releases it inside
driving force = ∆ [ ]
Important for sugar
transport

31. Selective Transport
Facilitated Diffusion (carriers)
Characteristics
1) saturable
2) specific
3) passive: transports
down ∆ []

32. Selective Transport
1) Channels
2) Facilitated Diffusion (carriers)
Passive transport should equalize [ ]
Nothing in a plant cell is at equilibrium!

33. Selective Transport
Passive transport should equalize [ ]
Nothing in a plant cell is at equilibrium!
Solution: use energy to transport specific ions against their ∆ [ ]

34. Active Transport
Integral membrane proteins
use energy to transport specific ions against their ∆ [ ]
allow cells to concentrate some chemicals, exclude others

35. Active Transport
Characteristics
1) saturable
ions/s
molecules/s

36. Active Transport
Characteristics
1) saturable
2) specific

37. Active Transport
Characteristics
1) saturable
2) specific
3) active: transport up ∆ [ ] (or ∆ Em)

38. 4 classes of Active transport ATPase proteins
1) P-type ATPases (P = “phosphorylation”)
Na/K pump
Ca pump in ER & PM
H+ pump in PM
pumps H+ out of cell

39. 4 classes of Active transport ATPase proteins
1) P-type ATPases (P = “phosphorylation”)
2) V-type ATPases (V = “vacuole”)
H+ pump in vacuoles

40. 4 classes of Active transport ATPase proteins
1) P-type ATPases (P = “phosphorylation”)
2) V-type ATPases (V=“vacuole”)
3) F-type ATPases (F = “factor”) a.k.a. ATP synthases
mitochondrial ATP synthase
chloroplast ATP synthase

41. 4 classes of Active transport ATPase proteins
1) P-type ATPases (P = “phosphorylation”)
2) V-type ATPases (V = “vacuole”)
3) F-type ATPases (F = “factor”)
4) ABC ATPases (ABC = “ATP Binding Cassette”)
multidrug resistance proteins

42. 4 classes of Active transport ATPase proteins
1) P-type ATPases (P = “phosphorylation”)
2) V-type ATPases (V = “vacuole”)
3) F-type ATPases (F = “factor”)
4) ABC ATPases (ABC = “ATP Binding Cassette”)
multidrug resistance proteins
pump hydrophobic drugs out of cells
very broad specificity

43. Secondary active transport
Uses ∆ [ ] created by active transport to pump something else across a membrane against its ∆ [ ]

44. Secondary active transport
Uses ∆ [ ] created by active transport to pump something else across a membrane against its ∆ [ ]
Symport: both substances pumped same way

45. Secondary active transport
Uses ∆ [ ] created by active transport to pump something else across a membrane against its ∆ [ ]
Symport: both substances pumped same way
Antiport: substances
pumped opposite ways

46. Secondary active transport
Uses ∆ [ ] created by active transport to pump something else across a membrane against its ∆ [ ]
Symport: both substances pumped same way
Antiport: substances
pumped opposite ways

47. Nutrient uptake
Gases enter/exit by diffusion down their ∆ [ ]

48. Nutrient uptake
Gases enter/exit by diffusion down their ∆ [ ]
Ions vary dramatically!

49. Nutrient uptake
Gases enter/exit by diffusion down their ∆ [ ]
Ions vary dramatically!
H+ is actively pumped out of cell by P-type H+ -ATPase

50. Nutrient uptake
Gases enter/exit by diffusion down their ∆ [ ]
Ions vary dramatically!
H+ is actively pumped out of cell by P-type H+ -ATPase
and into vacuole by V-type!

51. Nutrient uptake
H+ is actively pumped out of cell by P-type H+ -ATPase
and into vacuole by V-type!
Main way plants make membrane potential (∆Em)!

52. Nutrient uptake
H+ is actively pumped out of cell by P-type H+ -ATPase
and into vacuole by V-type!
Main way plants make membrane potential (∆Em)!
K+ diffuses through channels down ∆Em

53. Nutrient uptake
K+ diffuses through channels down ∆Em
Also taken up by transporters

54. Nutrient uptake
K+ diffuses through channels down ∆Em
Also taken up by transporters
some also transport Na+

55. Nutrient uptake
K+ diffuses through channels down ∆Em
Also taken up by transporters
some also transport Na+
why Na+ slows
K+ uptake?

56. Nutrient uptake
K+ diffuses through channels down ∆Em
Also taken up by transporters
some also transport Na+
why Na+ slows
K+ uptake?
Na+ is also expelled
by H+ antiport

57. Nutrient uptake
K+ diffuses through channels down ∆Em
Also taken up by transporters
some also transport Na+
why Na+ slows
K+ uptake?
Na+ is also expelled
by H+ antiport
Enters through channels

58. Nutrient uptake
Na+ is also expelled
by H+ antiport
Enters through channels
Ca2+ is expelled by P-type
ATPases in PM

59. Nutrient uptake
Ca2+ is expelled by P-type ATPases in PM
& pumped into vacuole & ER by H+ antiport & P-type

60. Nutrient uptake
Ca2+ is expelled by P-type ATPases in PM
pumped into vacuole & ER by H+ antiport & P-type
enters cytosol via gated channels

61. Nutrient uptake
PO43-, SO42-, Cl- & NO3-
enter by H+ symport

62. Nutrient uptake
PO43-, SO42-, Cl- & NO3- enter by H+ symport
also have anion transporters of ABC type

63. Nutrient uptake
PO43-, SO42-, Cl- & NO3- enter by H+ symport
also have anion transporters of ABC type
and anion channels

64. Nutrient uptake
PO43-, SO42-, Cl- & NO3- enter by H+ symport
also have anion transporters of ABC type
and anion channels
Plants take up N many ways

65. Nutrient uptake
Plants take up N many ways: NO3- & NH4+ are main forms

66. Nutrient uptake
Plants take up N many other ways
NO3- also by channels
NH3 by diffusion
NH4+ by carriers

67. Nutrient uptake
Plants take up N many other ways
NO3- by channels
NH3 by diffusion
NH4+ by carriers
NH4+ by channels

68. Nutrient uptake
Plants take up N many other ways
3 families of H+ symporters take up amino acids

69. Nutrient uptake
Plants take up N many other ways
3 families of H+ symporters take up amino acids
Also have many peptide transporters
some take up di- & tri-
peptides by H+ symport

70. Nutrient uptake
Plants take up N many other ways
3 families of H+ symporters take up amino acids
Also have many peptide transporters
some take up di- & tri-
peptides by H+ symport
others take up tetra- &
penta-peptides by H+ symport

71. Nutrient uptake
Plants take up N many other ways
3 families of H+ symporters take up amino acids
Also have many peptide transporters
some take up di- & tri-
peptides by H+ symport
others take up tetra- &
penta-peptides by H+ symport
Also have ABC transporters
that import peptides

72. Nutrient uptake
Plants take up N many other ways
3 families of H+ symporters take up amino acids
Also have many peptide transporters
some take up di- & tri-
peptides by H+ symport
others take up tetra- &
penta-peptides by H+ symport
Also have ABC transporters
that import peptides
N is vital!
NO3- & NH4+ are main forms

73. Nutrient uptake
Metals are taken up by ZIP proteins & by ABC transporters
same protein may import Fe, Zn & Mn!

74. Nutrient uptake
Much is coupled to
pH gradient

75. Nutrient transport in roots
Move from soil to endodermis in apoplast

76. Nutrient transport in roots
Move from soil to endodermis in apoplast
Move from endodermis to xylem in symplast

77. Nutrient transport in roots
Move from endodermis to xylem in symplast
Transported into xylem by H+ antiporters

78. Nutrient transport in roots
Move from endodermis to xylem in symplast
Transported into xylem by H+ antiporters, channels

79. Nutrient transport in roots
Transported into xylem by H+ antiporters, channels,pumps

80. Nutrient transport in roots
Transported into xylem by H+ antiporters, channels,pumps
Lowers xylem water
potential -> root pressure

81. Water Transport
Passes water & nutrients to xylem
Ys of xylem makes root pressure
Causes guttation: pumping water into shoot

82. Transport to shoot
Nutrients move up
plant in xylem sap

83. Nutrient transport in leaves
Xylem sap moves through apoplast
Leaf cells take up what
they want

84. Nutrient assimilation
Assimilating N and S is
very expensive!
Reducing NO3- to NH4+
costs 8 e- (1 NADPH +
6 Fd)

85. Nutrient assimilation
Assimilating N and S is
very expensive!
Reducing NO3- to NH4+
costs 8 e- (1 NADPH +
6 Fd)
Assimilating NH4+ into
amino acids also costs
ATP + e-

86. Nutrient assimilation
Assimilating N and S is very expensive!
Reducing NO3- to NH4+ costs 8 e- (1 NADPH + 6 Fd)
Assimilating NH4+ into amino acids also costs ATP + e-
Nitrogen fixation costs 16 ATP + 8 e-

87. Nutrient assimilation
Assimilating N and S is very expensive!
Reducing NO3- to NH4+ costs 8 e- (1 NADPH + 6 Fd)
Assimilating NH4+ into amino acids also costs ATP + e-
Nitrogen fixation costs 16 ATP + 8 e-
SO42- reduction to S2- costs 8 e- + 2ATP

88. Nutrient assimilation
Assimilating N and S is very expensive!
Reducing NO3- to NH4+ costs 8 e- (1 NADPH + 6 Fd)
Assimilating NH4+ into amino acids also costs ATP + e-
Nitrogen fixation costs 16 ATP + 8 e-
SO42- reduction to S2- costs 8 e- + 2ATP
S2- assimilation into Cysteine costs 2 more e-
Most explosives are based on N or S!