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Flashcards in Plant Hormones Deck (74):
2

Stages of the embryo developmental stage

Early embryogenesisMid embryogenesis +Seed developmentGermination

3

Stages of seedling growth

Triple Response (Phase I)Etiolated GrowthDe-etiolation (greening)

4

Stages of a mature plants growth

Growth/Tropic GrowthShoot branching/Lateral Bud GrowthRoot branching/later bud growthSenescenceStomate controlFlowering

5

Stages of a plants reproductive effort

Fruit developmentFruit Ripening

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List all hormones involved in the plant growth

Abscisic Acid (ABA)AuxinBrassinosteroidsCytokininsEthyleneGibberellinsJasmonatesOligosaccharinsSalicylic AcidSystemin(AAB-CEG-JOSS)

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AAB-CEG-JOSS

my way of remembering all hormones

8

What happens during early embryogenesis (say the general action and then try to go scientifically)

Plant cells develop into different organs-polarity (shoot vs leaf; organ development)-histo-differentiation (different tissue cells develop)Nutrition of the embryo-nutrition provided by the endosperm

9

What is the endosperm?

Tissue that surrounds the embryo that provides nutrition

10

What happens during mid embryogenesis/seed development (say the general action and then try to go scientifically)

Embryo stops growing-Embryo maturity (due to allowing it to go through dormancy)Stores nutrients-Starch reserve accumulationSeed dries out to keep embryo at a specific size-seed dormancyHormones make sure endosperm has a large enough storage of starch/nutrients-"desiccation tolerance"

11

What happens during fruit develpoment? (say the general action and then try to go scientifically)

Fruit growth

12

What happens during fruit ripening? (say the general action and then try to go scientifically)

Fruit ripening

13

What happens during germination? (say the general action and then try to go scientifically)

Embryo emerges from the seed-germinationEmbryo uses stored starch-reserve mobilization

14

What happens during Triple Response (Phase I) ? (say the general action and then try to go scientifically)

Plant fattens/lateral growth-radial swellingSprout starts bending over-apical hookSprout grows with its tip pointing down at an angle/how ever the hell it wants-agravitropic growth (independent of gravity)

15

What happens during etiolated growth? (say the general action and then try to go scientifically)

DISCLAIMER: only happens in the darkplant grows really really tall really fast-etiolated growth; cell wall loosening and elongationplants will be white (DO NOT turn green)-Inhibition of plastid differentiation/chloroplast maturation

16

What happens during de-etiolated growth? (say the general action and then try to go scientifically)

Leaves expandPlant stops growing vertically-stem elongation inhibited;endosperm reserve goes to turning plant greenPlant turns green-chloroplasts develop thylakoid stacksDevelops photosynthesis ability-gene expression for light-dependent processes

17

What happens during Growth/Tropic Growth? (say the general action and then try to go scientifically)

Plant grows toward light-phototropism (blue light)Plant develops each section of its body-embryonic pattern formation; all parts of the body grows as a whole

18

What happens during shoot branching/lateral bud growth? (say the general action and then try to go scientifically)

Branches in the plant grow-trade off of effects of hormones to promote and inhibit shoot branching/lateral bud growth

19

What happens during root branching/lateral bud growth? (say the general action and then try to go scientifically)

Roots branch out in specific sections-interaction between hormones (auxin/cyto) to stop and start root branch growing; some develop in accordance to stress, more stress=less growing

20

What happens in senescence? (say the general action and then try to go scientifically)

Leaves fall off-leaves transfer nutrients to the shoots then fall off

21

What happens in stomate control? (say the general action and then try to go scientifically)

Stomatas close-in reaction to stress the stomata close/opening through signaling by hormones

22

What happnens in flowering? (say the general action and then try to go scientifically)

Regulation of flowering-hormones lead to 2-component regulators that determine when/if plants flower

23

What hormones are involved in 2-component regulators and in what process?

ethylene --> Triple Responsephytochrome --> FloweringCK

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Actions of Abscisic acid (ABA)

seed dormancy (mid embryogenesis)de-etiolation (inhibits BR)closes stomatasenescencecontrols lateral root growth

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Actions of Auxin

polarity and cell differentiationstem elongationstops shoot branchingpromotes root branchingphototropismfruit growthopens stomata

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Actions of Brassinosteroids (BR)

stem elongation and pollen tubesvascular tissue differentiationbasically only involved in etiolated growth

27

Actions of Cytokinins (CK)

Embryo nutritionshoot branching (cell division and later growth)Inhibits root branchinginhibits senescenceFruit growth

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Actions of Ethylene

Triple ResponseFruit ripeninginhibits all cell growth (and gravitropism)senescence

29

Actions of Gibberellins (GA)

Embryo nutritionFruit developmentBreaks dormancygermination (mobilizes nutrition)elongated growth (shoot growth)

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Jasmonates

defense against pathogens/herbivores

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Oligosaccharins

defense against pathogenscell differentiationlimits auxin concentrations

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Salicylic Acid

resistance to pathogens

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Systemin

Jasmonate production in response to tissue damages

34

Strigo-lactones?

Random other hormone that inhibits shoot branching

35

Describe the hormone response process in early ebryogenesis

1) Auxin - polarity, histo-differentiation2) CK - nutrition of embryo3) GA - nutrition of embryo

36

Describe the hormone response process in

1)ABA-embryo maturation-reserve accumulation-dormancy-dessication tolerance

37

Describe the hormone response process in germination

1)GA - reserve mobilization

38

Describe the hormone response process in Triple Response

1) Ethylene - Radial swelling - apical hook - agravitropic growth

39

Describe the hormone response process in etiolated growth

1) Brassinosteroid (BR) - promotes cell elongation (shoot) - inhibits chloroplast maturation2) Auxin and GA are complement hormones to this process

40

Describe the hormone response process in De-etiolated growth

1) ABA-expands leaves- inhibits BR; uses endosperm reserves to "green" the plant-develop chloroplasts (thylakoids)-grants ability for light-dependent reactions

41

Describe the hormone response process in growth/tropic growth

1) Auxin-elongation with phototropism-forms differentiated body patterns/organs2) ABA - stops growing3) Ethylene - stops growing

42

Describe the hormone response process in shoot branching/lateral bud growth

1) Auxin - first keeps shoot branching inhibited ("energy to grow upward")2) Cytokinin promotes shoot branching3)Strigo-lactones stop shoot branching

43

Describe the hormone response process in root branching/lateral bud growth

1) Auxin - starts with growing root branching2) CK - stops branching3) ABA - controls root elongation in reference to stress (mild = grow ; severe = no elongation)

44

Describe the hormone response process in senescence

1) CK- keeps leaves from falling off2) Ethylene - makes leaves fall off3) ABA - makes leaves fall off

45

Describe the hormone response process in Stomtate control

1) ABA - closes stomata in response to stress2) Auxin - opens stomata

46

Describe the hormone response process in flowering

1) Phytochrome mediated- response to red and far red light

47

What is a phytocrhome?

a photoreceptor pigment that is directed towards red and far red light to regulate the time of flowering

48

Which hormone(s) are not plant specific?

ABA

49

Hormones that cause de-repression

Auxin,, ABA, BR, Ethylene, GA"AABEG"

50

Antagonistic relationship of hormones for morphology

Auxin vs Cytokinin

51

The inhibitor of germination

ABA

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The inhibitor of the triple response

light

53

What is the foolish seedling?

The mutant of germination, plant grows super tall too fast and then is too weak and dwindles over

54

One fruit can also ripen surrounding fruits due to

ethylene gas

55

Describe GA's process of mobilizing embryo reserves for germination

1) GA signals aleurone (receptors on the cell surface & nucleus)2) 2nd messengers create 2 pathways: Ca2+ and cGMP3) synthesizes amylase and sends it to endosperm to absorb starch4) hydrolizes starch to GLC5)GLC absorbed by embryo for growth

56

Describe cgMP pathway for germination

1) GA binds to surface/nuclear receptor2) it binds ubiquitin + proteosome to degrade the repressor 3)gene expression for the synthesis of amylase happens4) regulator promotes amylase secretion

57

Describe Ca2+ pathway for germination

Ca2+ from vacuoles directly promotes amylase secretion

58

What physical attribute induces ethylene synthesis

pressure

59

Describe the mechanism for the triple response

1) Pressure from the soil induces ethylene synthesis2) attaches to 2 component regulators and crosses PM (photoreceptor-cytokines)3) ER membrane receptor binds ethylene4) CTR1 repressor removed5) EIN 2/3 activates gene expressionv (through downstream activators)

60

What parts are the 2 component regulators?

sensor kinase & response regulator

61

Which is the only hormone that binds to ER in the plant

Ethylene

62

During etiolated growth what color are the plants

white

63

Describe the mechanism for etiolated growth

1) BR binds to receptor dimers on PM surface2) phosphorylation cascade3) de-repression of kinase (de-phosphorilates) and transcripton factors4) activated transcription factors promote gene expression

64

In order for genes to be activated by BR, the transcription factors have to undergo

de-phosphorilation

65

Auxin receptors are

membrane and cytoplasmic

66

Describe the growth/ tropic growth mechanisms

1) auxin does the exact de-repression process GA does for reserve mobilization2) Acid growth3) Long term de-repression

67

What is acid growth and describe the mech for it

wall loosening1) proton pump creats a pH gradient 2) gradient creates a cell ANION trap(regular Auxin is neutral in cell wall then H+ pumps make it acidic in the cell to loosen it ph=4)

68

Mech for shoot branching/lateral bud growth

Auxin is produced in the shoot and transported to the rootsInterchange of Aux and CK/Strigo-lactones in growing branches

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Mech for root branching/lateral bud growth

CK produced in roots transports to shootsExchange of Aux a and CK /ABA in branching rootsABA response to stress in growing root branches

70

Mech for senescence

1) CK 2 component receptors-works the same way EXCEPT this time active form is phosphorliated

71

Stomate control mech

1) De-repression by ABA (G-proteins, 2ndary messengers etc)

72

Flowering Mech

response to red and far red light (SDP and LDP)long night periods flower SDPshort night periods flower LDP

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mutant to growth/tropic growth

axr

74

mutant to etiolated growth

hy (blind)det (de-etiolated)cop (constitutively photomophogenic)

75

ABA deficiency leads to

short and wilty plants due to not being able to close stomata