1. Phytoremediation
Plant products
Biofuels
Effects of seed spacing on seed germination
Effects of nutrient deprivation
Effects of stresses
Climate/CO2 change
Non-coding RNAs
Biotechnology
Plant movements: flytraps, mimosa, soybeans
Carnivorous plants
Stress responses/stress avoidance
Plant signaling (including neurobiology)
Flowering?
Hormones?
Plant pathology?
Plant tropisms and nastic movements
Root growth responses
Metal toxicity?
Circadian rhythms?
Effects of magnetic fields?
Effects of different colors of light on plant growth?

2. Assignment 1
Pick a topic that you think is worth studying
Try to convince the group in 5-10 minutes why yours is best
Why it is significant
what is known/what isn’t known
Some plants that we might use
Some experiments that we could perform by the end of the semester.

3. Endomembrane system
Organelles derived from the ER
1) ER
2) Golgi
3) Vacuoles
4) Plasma
Membrane
5) Nuclear
Envelope
6) Endosomes
7) Oleosomes

4. endosymbionts
Peroxisomes
Mitochondria
3) Plastids

5. cytoskeleton
network of proteins which give cells their shape
also responsible for shape of plant cells because guide cell wall formation
left intact by detergents that extract rest of cell

6. WATER
Plants' most important chemical
most often limits productivity

7. Climate change will alter rainfall
Overall prediction is that crops will suffer in many parts of world

8. WATER
Plants' most important chemical
most often limits productivity
Often >90% of a plant cell’s weight

9. WATER
Plants' most important chemical
most often limits productivity
Often >90% of a plant cell’s weight
Gives cells shape

10. WATER
Plants' most important chemical
most often limits productivity
Often >90% of a plant cell’s weight
Gives cells shape
Dissolves many chem

11. WATER
Dissolves many chem
most biochem occurs in water
Source of e- for PS

12. WATER
most biochem occurs in water
Source of e- for PS
Constantly lose water due to PS (1000 H2O/CO2)

13. WATER
most biochem occurs in water
Source of e- for PS
Constantly lose water due to PS
Water transport is crucial!

14. WATER
Water transport is crucial!
SPAC= Soil Plant Air Continuum
moves from soil->plant->air

15. Plant Water Uptake
Water is drawn through plants along the SPAC, using its special props to draw it from the soil into the air

16. WATER
Formula = H2O
Formula weight = 18 daltons
Structure = tetrahedron, bond angle 104.5˚

17. WATER
Structure = tetrahedron, bond angle 104.5˚
polar: O is more attractive to electrons than H
+ on H
- on O

18. Water
Polarity is reason for water’s properties
water forms H-bonds with polar molecules

19. Water
Polarity is reason for water’s properties
water forms H-bonds with polar molecules
Hydrophilic = polar molecules
Hydrophobic = non-polar molecules

20. Properties of water
Cohesion = water H-bonded to water

21. Properties of water
Cohesion = water H-bonded to water
-> reason for surface tension

22. Properties of water
Cohesion = water H-bonded to water
-> reason for surface tension
-> why water can be drawn from roots to leaves

23. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else

24. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
capillary action

25. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
capillary action
why things dissolve in water

26. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
Cohesion and adhesion are crucial for water movement in plants!

27. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
Cohesion and adhesion are crucial for water movement in plants!
Surface tension & adhesion in mesophyll creates force that draws water through the plant!

28. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
3) high specific heat
absorb heat when break H-bonds: cools leaves

29. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
3) high specific heat
absorb heat when break H-bonds
Release heat when form H-bonds

30. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
3) high specific heat
4) Ice floats

31. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
3) high specific heat
4) Ice floats
5) Universal solvent

32. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
3) high specific heat
4) Ice floats
5) Universal solvent
Take up & transport
nutrients dissolved in
water

33. Properties of water
5) “Universal” solvent
Take up & transport nutrients dissolved in water
Transport organics dissolved in water

34. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
3) high specific heat
4) Ice floats
5) Universal solvent
6) Hydrophobic interactions

35. Properties of water
1) Cohesion = water H-bonded to water
2) Adhesion = water H-bonded to something else
3) high specific heat
4) Ice floats
5) Universal solvent
6) Hydrophobic interactions
7) Water ionizes

36. pH
[H+] = acidity of a solution
pH = convenient way
to measure acidity
pH = - log10 [H+]
pH 7 is neutral:
[H+] = [OH-]
-> at pH 7 [H+]
= 10-7 moles/l
pH of cytoplasm = 7.2
pH of stroma & matrix
= 8
pH of apoplast = 5.5
pH of lumen = 4.5

37. pH
Plants vary pH to control many processes!

38. pH
Plants vary pH to control
many processes!
Plants alter roots to
aid uptake

39. Water movement
Diffusion: movement of single molecules down ∆[ ] due to random motion until [ ] is even
Driving force?

40. Water movement
Diffusion: movement of single molecules down ∆[ ] due to random motion until [ ] is even
Driving force: lowers free energy
∆G = ∆H- T∆S

41. Water movement
Diffusion: movement of single molecules down ∆[ ] due to random motion until [ ] is even
Bulk Flow: movement of groups of
molecules down a pressure gradient

42. Water movement
Diffusion: movement of single molecules down ∆[ ] due to random motion until [ ] is even
Bulk Flow: movement of groups of
molecules down a pressure gradient
Independent of ∆ [ ] !

43. Water movement
Diffusion: movement of single molecules down ∆[] due to random motion until [ ] is even
Bulk Flow: movement of groups of molecules down a pressure gradient
Independent of ∆[ ] !
How water moves through xylem

44. Water movement
Diffusion: movement of single molecules down [] due to random motion until [ ] is even
Bulk Flow: movement of groups of molecules down a pressure gradient
Independent of ∆ [ ] !
How water moves through xylem
How water moves through soil and apoplast

45. Water movement
Bulk Flow: movement of groups of molecules down a pressure gradient
Independent of ∆ [ ] !
How water moves through xylem
Main way water moves through soil and apoplast
Very sensitive to radius of vessel: increases as r4

46. Water movement
Diffusion: movement of single molecules down ∆[] due to random motion until [ ] is even
Bulk Flow: movement of groups of molecules down a pressure gradient
Independent of ∆[ ] !
How water moves through xylem
Main way water moves through soil and apoplast
Very sensitive to radius of vessel: increases as r4
Osmosis: depends on bulk flow and diffusion!

47. Water movement
Osmosis: depends on bulk flow and diffusion!
water crosses membranes but other solutes do not
water tries to even its [ ] on each side

48. Water movement
Osmosis: depends on bulk flow and diffusion!
water crosses membranes but other solutes do not
water tries to even its [ ] on each side
other solutes can’t: result is net influx of water

49. Water movement
Osmosis: depends on bulk flow and diffusion!
Moves through aquaporins, so rate depends on pressure and [ ] gradients!

50. Water movement
Osmosis: depends on bulk flow and diffusion!
Moves through aquaporins, so rate depends on pressure and [ ] gradients!
Driving force = water's free energy (J/m3 = MPa)

51. Water potential
Driving force = water's free energy
= water potential Yw
Important for many aspects of
plant physiology

52. Water potential
Driving force = water's free energy = water potential Yw
Water moves to lower its potential

53. Water potential
Driving force = water's free energy = water potential Yw
Water moves to lower its potential

54. Water potential
Driving force = water's free energy = water potential Yw
Water moves to lower its potential
Depends on:
[H2O]: Ys (osmotic potential)

55. Water potential
Water moves to lower its potential
Depends on:
[H2O]: Ys (osmotic potential)
Pressure : Yp
Turgor pressure inside cells

56. Water potential
Water moves to lower its potential
Depends on:
[H2O]: Ys (osmotic potential)
Pressure : Yp
Turgor pressure inside cells
Negative pressure in xylem!

57. Water potential
Water moves to lower its potential
Depends on:
[H2O]: Ys (osmotic potential)
Pressure Yp
Gravity Yg
Yw = Ys +Yp + Yg

58. Water potential
Water moves to lower its potential
Depends on:
[H2O]: Ys (osmotic potential)
Pressure Yp
Gravity Yg
Yw = Ys +Yp + Yg
Yw of pure water at sea level
& 1 atm = 0 MPA

59. Water potential
Yw = Ys +Yp + Yg
Yw of pure water at sea level & 1 atm = 0 MPA
Ys (osmotic potential) is always negative

60. Water potential
Yw = Ys +Yp + Yg
Yw of pure water at sea level & 1 atm = 0 MPA
Ys (osmotic potential) is always negative
If increase [solutes] water will move in

61. Water potential
Yw = Ys +Yp + Yg
Yw of pure water at sea level & 1 atm = 0 MPA
Ys (osmotic potential) is always negative
If increase [solutes] water will move in
Yp (pressure potential) can be positive or negative

62. Water potential
Yw = Ys +Yp + Yg
Yw of pure water at sea level & 1 atm = 0 MPA
Ys (osmotic potential) is always negative
If increase [solutes] water will move in
Yp (pressure potential) can be positive or negative
Usually positive in cells to counteract Ys

63. Water potential
Yp (pressure potential) can be positive or negative
Usually positive in cells to counteract Ys
Helps plants stay same size despite daily fluctuations in Yw

64. Water potential
Yw = Ys +Yp + Yg
Yp (pressure potential) can be positive or negative
Usually positive in cells to counteract Ys
Helps plants stay same size
despite daily fluctuations in Yw
Yp in xylem is negative, draws
water upwards

65. Water potential
Yw = Ys +Yp + Yg
Yp (pressure potential) can be positive or negative
Usually positive in cells to counteract Ys
Helps plants stay same size
despite daily fluctuations in Yw
Yp in xylem is negative, draws
water upwards
Yg can usually be ignored, but
important for tall trees

66. Water potential
Measuring water potential

67. Water potential
Measuring water potential
Ys (osmotic potential) is “easy”
Measure concentration of solution in equilibrium with cells

68. Water potential
Measuring water potential
Ys (osmotic potential) is “easy”
Measure concentration of solution in equilibrium with cells
Yg (gravity potential) is easy: height above ground
-0.01 Mpa/m

69. Water potential
Measuring water potential
Ys (osmotic potential) is “easy”
Measure concentration of solution in equilibrium with cells
Yg (gravity potential) is easy: height above ground
YP (pressure potential) is hard!
Pressure bomb =
most common technique

70. Water potential
Measuring water potential
Ys (osmotic potential) is “easy”
Measure concentration of solution in equilibrium with cells
Yg (gravity potential) is easy: height above ground
YP (pressure potential) is hard!
Pressure bomb =
most common technique
Others include pressure
transducers, xylem probes

71. Measuring water potential
YP (pressure potential) is hard!
Pressure bomb =
most common technique
Others include pressure
transducers, xylem probes
Therefore disagree about H2O
transport in xylem

72. Water transport
Therefore disagree about H2O
transport in xylem
Driving force = evaporation
in leaves (evapotranspiration)
Continuous H2O column
from leaf to root draws up
replacement H2O from soil (SPAC)

73. Water transport
Driving force = evaporation
in leaves (evapotranspiration)
Continuous H2O column
from leaf to root draws up
replacement H2O
Exact mech controversial

74. Water transport
Driving force = evaporation in leaves (evapotranspiration)
Continuous H2O column from leaf to root draws up
replacement H2O
Exact mech controversial
Path starts at root hairs

75. Water transport
Path starts at root hairs
Must take water from soil

76. Water transport
Path starts at root hairs
Must take water from soil
Ease depends on availability
& how tightly it is bound

77. Water transport
Path starts at root hairs
Must take water from soil
Ease depends on availability & how tightly it is bound
Binding depends on particle size & chem

78. Water transport
Must take water from soil
Ease depends on availability & how tightly it is bound
Binding depends on particle size & chem
Availability depends on amount in soil pores

79. Water transport
Availability depends on amount in soil pores
Saturation: completely full

80. Water transport
Availability depends on amount in soil pores
Saturation: completely full
Field capacity: amount left after gravity has drained excess

81. Water transport
Availability depends on amount in soil pores
Saturation: completely full
Field capacity: amount left after gravity has drained excess
Permanent wilting point: amount where soil water potential is too negative for plants to take it up