1. Friday
Present a plant stressor, what is known about it, and why it might affect plant 2˚ compounds in an ~ 10 minute presentation.
Alternative: present another good plant/stressor response to study and why we should choose it over the ones already chosen.

2. John Austin:
Tom Nawrocki:
Maria Chinikaylo: effect of atrazine herbicide on glutathione in corn
Jared Nicholoff:
David Pupaza: Fungal attack
Cassia Cole:
Kyle Schimmel:
Christina Gambino: predation on caffeine coffee plant
Nathan Seabridge: sulfur deprivation on onions
Andrew Hasuga: ozone
Kenneth Werkheiser: Agrobacterium tumefaciens
Kelvin Mejia: High soil salinity
Alexis Morgan: Sulfur deprivation on garlic
Matt Yatison: UV radiation
Michael Yucha: Cold Stress
Catherin Morocho:
Atrazine? Cold? Shaking?Nutrient deprivation? Bacteria? Nematodes?
Ozone? Smog? Heavy metals? Predation? Heat?

3. Natural Products
>100,000 types; 3 main groups
>30,000 terpenoids: made from isoprene units
>12,000 Alkaloids: derived from amino acids: contain N
>8,000 phenolics: contain phenol ring

4. Other natural products
~ 100 cyanogenic glycosides
Release cyanide when plant is damaged
Found in seeds of apricots, cherries, other fruits
Laetrile

5. Other natural products
> 100 glucosinolates: contain S and N
Mainly found in Brassicaceae (crucifers)
Made from modified amino acids bonded to glucose
Function in defense

6. Other natural products
The genus Allium produces sulfoxides derived from cysteine
When plants are damaged they are converted to pungent volatiles

7. Seeds
Seeds are unique feature of plants
Plant dispersal units
Must survive unfavorable conditions until they reach
suitable place (and time) to start next generation
Are dormant; dehydration is key
Germinate when conditions are right

8. Seed Development
Maturation: cell division ± ceases, but cells still expand
Activate new genes for making storage compounds
Storage compounds are key for seedlings and crops
Proteins, lipids & carbohydrates but vary widely
Many 2˚ metabolites

9. Seed Development
Next prepare for desiccation as ABA made by embryo (+endosperm) increases
Make proteins & other molecules (eg trehalose) that help tolerate desiccation
Next dehydrate (to 5% moisture content) and go dormant

10. Seed Development
Coat-imposed dormancy (maternal effect)
Preventing water uptake.
Mechanical constraint
Interference with gas exchange
Retaining inhibitors (ABA)
Inhibitor production (ABA)
Embryo dormancy (Zygotic effect)

11. Seed germination
Seeds remain dormant until sense appropriate conditions:
Water
Temperature: some seeds require vernalization = prolonged cold spell
Many require light: says photosynthesis is possible
often small seeds with few reserves

12. Seed germination
Seeds remain dormant until sense appropriate conditions:
Many require light: says that they will soon be able to photosynthesize: often small seeds with few reserves
Hormones can also trigger (or stop) germination
ABA blocks it
GA stimulates it

13. Seed germination
Seeds remain dormant until sense appropriate conditions:
Many require light: says that they will soon be able to photosynthesize: often small seeds with few reserves
Hormones can also trigger (or stop) germination
ABA blocks it
GA stimulates it
Germination is a two step process
Imbibition

14. Seed germination
Germination is a two step process
Imbibition is purely physical: seed swells as it absorbs water until testa pops.
Even dead seeds do it.

15. Seed germination
Germination is a two step process
Imbibition is purely physical: seed swells as it absorbs water until testa pops.
Even dead seeds do it.
Seeds with endosperm pop testa first, then endosperm

16. Seed germination
Germination is a two step process
Imbibition is purely physical: seed swells as it absorbs water until testa pops.
Even dead seeds do it.
Seeds with endosperm pop testa first, then endosperm
Separate processes: can pop testa but not endosperm

17. Seed germination
Germination is a two step process
Imbibition is purely physical: seed swells as it absorbs water until testa pops.
Even dead seeds do it.
Seeds with endosperm pop testa first, then endosperm
Separate processes: can pop testa but not endosperm
Testa and endosperm have different genotypes!

18. Seed germination
Germination is a two step process
Imbibition is purely physical: seed swells as it absorbs water until testa pops. Even dead seeds do it.
Seeds with endosperm pop testa first, then endosperm
Next embryo must start metabolism and cell elongation

19. Seed germination
Germination is a two step process
Imbibition is purely physical: seed swells as it absorbs water until testa pops. Even dead seeds do it.
Next embryo must start metabolism and cell elongation
This part is sensitive to the environment, esp T & pO2

20. Seed germination
Germination is a two step process
Next embryo must start metabolism and cell elongation
This part is sensitive to the environment, esp T & pO2
Hormones also play a complex role

21. Seed germination
Germination is a two step process
Next embryo must start metabolism and cell elongation
This part is sensitive to the environment, esp T & pO2
Hormones also play a complex role
GA, Ethylene and BR all stimulate

22. Seed germination
Germination is a two step process
Next embryo must start metabolism and cell elongation
This part is sensitive to the environment, esp T & pO2
Hormones also play a complex role
GA, Ethylene and BR all stimulate
ABA blocks

23. Seed germination
Germination is a two step process
Next embryo must start metabolism and cell elongation
This part is sensitive to the environment, esp T & pO2
Once radicle has emerged, vegetative growth begins

24. Vegetative growth
Once radicle has emerged, vegetative growth begins
Juvenile plants in light undergo photomorphogenesis

25. Vegetative growth
Once radicle has emerged, vegetative growth begins
Juvenile plants in light undergo photomorphogenesis
Juvenile plants in dark undergo skotomorphogenesis
Seek light: elongate hypocotyl, don’t unfold cotyledons

26. Vegetative growth
Once radicle has emerged, vegetative growth begins
Juvenile plants in light undergo photomorphogenesis
Expand cotyledons, start making leaves & photosynthetic apparatus

27. Vegetative growth
Once radicle has emerged, vegetative growth begins
Juvenile plants in light undergo photomorphogenesis
Expand cotyledons, start making leaves & photosynthetic apparatus
Initially live off reserves, but soon do net photosynthesis

28. Vegetative growth
Once radicle has emerged, vegetative growth begins
Initially live off reserves, but soon do net photosynthesis
Add new SAM in response
to auxin gradients
Add new branches from axillary
buds lower down stem if apical
dominance wanes

29. Vegetative growth
Once radicle has emerged, vegetative growth begins
Add new SAM in response to auxin gradients
Add new branches from axillary
buds lower down stem if apical
dominance wanes
Roots grow down seeking
water & nutrients

30. Vegetative growth
Once radicle has emerged, vegetative growth begins
Add new SAM in response to auxin gradients
Roots grow down seeking water & nutrients
1˚ (taproot) anchors plant
2˚ roots absorb nutrients

31. Vegetative growth
Once radicle has emerged, vegetative growth begins
Add new SAM in response to auxin gradients
Roots grow down seeking water & nutrients
1˚ (taproot) anchors plant
2˚ roots absorb nutrients
Continue to add cells
by RAM

32. Vegetative growth
Roots grow down seeking water & nutrients
Continue to add cells by RAM
Form lateral roots in maturation zone in response to nutrients & auxin/cytokinin

33. reproductive phase
Eventually switch to reproductive phase & start flowering
Are now adults!

34. reproductive phase
Eventually switch to reproductive phase & start flowering
Are now adults!
Triggered by FT protein: moves from leaves to shoot apex in phloem to induce flowering!

35. Transition to Flowering
Adults are competent to flower, but need correct signals
Very complex process!
Can be affected by:
Daylength
T (esp Cold)
Water stress
Nutrition
Hormones
Age

36. reproductive phase
Are now adults!
Very complex process!
Time needed varies from days to years

37. reproductive phase
Eventually switch to reproductive phase & start flowering
Are now adults!
Time needed varies from days to years.
Shoot apical meristem now starts making new organ: flowers, with many new structures & cell types

38. Senescence
Shoot apical meristem now starts making new organ: flowers, with many new structures & cell types
Eventually petals, etc senesce = genetically programmed cell death: controlled by specific genes

39. Senescence
Eventually petals, etc senesce = genetically programmed cell death: controlled by specific genes
Also seen in many other cases: deciduous leaves in fall, annual plants, older trees

40. Senescence
Induce specific senescence-associated genes ; eg DNAses, proteases, lipases
Also seen during xylem formation: when cell wall is complete cell kills itself

41. Senescence
Also seen during xylem formation: when cell wall is complete cell kills itself
Also seen as wound response: hypersensitive response
Cells surrounding the wound kill themselves

42. Senescence
Also seen during xylem formation: when cell wall is complete cell kills itself
Also seen as wound response: hypersensitive response
Cells surrounding the wound kill themselves
Some mutants do this w/o wound -> is controlled by genes!

43. Light regulation of Plant Development
Plants use light as food and information
Use information to control development

44. Light regulation of Plant Development
Plants use light as food and information
Use information to control development
germination

45. Light regulation of Plant Development
Plants use light as food and information
Use information to control development
Germination
Photomorphogenesis vs skotomorphogenesis

46. Light regulation of Plant Development
Plants use light as food and information
Use information to control development
Germination
Photomorphogenesis vs skotomorphogenesis
Sun/shade & shade avoidance

47. Light regulation of Plant Development
Germination
Morphogenesis
Sun/shade & shade avoidance
Flowering

48. Light regulation of Plant Development
Germination
Morphogenesis
Sun/shade & shade avoidance
Flowering
Senescence

49. Light regulation of growth
Plants sense
Light quantity

50. Light regulation of growth
Plants sense
Light quantity
Light quality (colors)

51. Light regulation of growth
Plants sense
Light quantity
Light quality (colors)
Light duration

52. Light regulation of growth
Plants sense
Light quantity
Light quality (colors)
Light duration
Direction it comes from

53. Light regulation of growth
Plants sense
Light quantity
Light quality (colors)
Light duration
Direction it comes from
Have photoreceptors
that sense specific
wavelengths

54. Light regulation of growth
Early work:
Darwin showed that
phototropism is
controlled by blue light

55. Light regulation of Plant Development
Early work:
Darwins : phototropism is controlled by blue light
Duration = photoperiodism (Garner and Allard,1920)
Maryland Mammoth tobacco flowers in the S but not in N

56. Light regulation of Plant Development
Early work:
Darwins : phototropism is controlled by blue light
Duration = photoperiodism (Garner and Allard,1920)
Maryland Mammoth tobacco flowers in the S but not in N
= short-day plant (SDP)

57. Light regulation of Plant Development
Duration = photoperiodism (Garner and Allard,1920) Maryland Mammoth tobacco flowers in the S but not in N
= short-day plant (SDP)
Measures night! 30" flashes during night stop flowers

58. Light regulation of growth
Duration = photoperiodism (Garner and Allard,1920) Maryland Mammoth tobacco flowers in the S but not in N
= short-day plant (SDP)
Measures night! 30" flashes during night stop flowers
LDP plants such as Arabidopsis need long days to flower

59. Light regulation of growth
Duration = photoperiodism (Garner and Allard,1920) Maryland Mammoth tobacco flowers in the S but not in N
= short-day plant (SDP)
Measures night! 30" flashes during night stop flowers
LDP plants such as Arabidopsis need long days to flower
SDP flower in fall, LDP flower in spring, neutral flower when ready

60. Light regulation of growth
Measures night! 30" flashes during night stop flowers
LDP plants such as Arabidopsis need long days to flower
SDP flower in fall, LDP flower in spring, neutral flower when ready
Next : color matters! Red light works best for flowering

61. Light regulation of growth
Next : color matters! Red light (666 nm)works best for flowering & for germination of many seeds!

62. Phytochrome
Next : color matters! Red light (666 nm)works best for flowering & for germination of many seeds!
But, Darwin showed blue works best for phototropism!

63. Phytochrome
Next : color matters! Red light (666 nm)works best for flowering & for germination of many seeds!
But, Darwin showed blue works best for phototropism!
Different photoreceptor!

64. Phytochrome
But, Darwin showed blue works best for phototropism!
Different photoreceptor!
Red light (666 nm) promotes germination
Far red light (>700 nm) blocks germination

65. Phytochrome
But, Darwin showed blue works best for phototropism!
Different photoreceptor!
Red light (666 nm) promotes germination
Far red light (>700 nm) blocks germination