Growth Hormones

Front 1

What does GA stimulate in plants

Back 1

stem growth in dwarf & rosette plants; cell division and cell wall extensibiolity in internode

Front 2

- cold temperature required for germination of certain seeds
GA (exongenous) can replace this process in some seeds

Back 2

Stratification

Front 3

cold temperature required for flowering (vernalization)
GA (exongenous) can replace this process in some seeds

Back 3

Vernalization

Front 4

winter wheat is biennial and needs cold temps to flower. what can be done to overcome this process?

Back 4

GA exogenous

Front 5

What does GA regulate

Back 5

regulates transition from juvenile to adult phases
woody species have different leaves, GA (exogenous) can induce Ivy to revert from mature to juvenile forms.

Front 6

Describe sex determination in GA plants

Back 6

moneocious plants (corn)
dicots (spinach)

Front 7

What does Ga need in order to cause male flowers

Back 7

short days and cooler nights to induce tassesl; spinach is opposite, staminate flower is produeced when GA is added.

Front 8

How does GA effect fruit?

Back 8

Promote Fruit Set – Parthenocarpic Fruit
Grapes Thompson’s seedless grapes – two treatmets – 1st to induce fruit
formation and 2nd to increase size

Front 9

Mechanism of Gibberellin Action

Back 9

Malting
Mobilizing Endosperm Reserves

Hint 9

How does GA affect seed germination. what does it activate?

Front 10

Describe the various processes of where GA is formed, what is induced, where it is moved, etc.

Back 10

GA formed in embryo of cereal grains; induces alpha production occurs in
aleurone layers; moves to endosperm where it breaks down starch into sugar
which is mobilized out stimulating growth (germination)
GA stimulates transcription of alpha amylase mRNA

Front 11

Cytokinin: synthetic forms?
Natural forms?

Back 11

synthetic: kinetin
natural: zeatin

Front 12

Where is cytokinin synthesized?

Back 12

in root apical meristems, small amounts in young leaves & shoot meristems

Front 13

How is cytokinin transported?

Back 13

through xylem tissue

Front 14

What is cytokinins main function?

Back 14

stimulates cell division in meristematic regions and cambiums

Front 15

What inducts tubors in cytokinin?

Back 15

abrobacterium tubefaciens

Front 16

What is crown Gall disease?

Back 16

when agrobacterium tumefaciens invades a wound it can cause the neoplstic (tumor-forming) disease called crown gall. Agrobacterium changes cell character and they divide non-stop bc of wound response. They produce an unorganized mass of tumorelike tissue called gall. Heating this tissue to 42 degrees kills bacterium. Tissues will continue to grow forming a callus.

Front 17

Low kinetin/ high auxin favors?

Back 17

root differentiation

Front 18

higher kinetin/ lower auxin favors?

Back 18

shoot differentiation

Front 19

cytokinetin regulated processes

Back 19

Modify Apical Dominance and Promote Lateral Bud Growth
Cytokinins Delay Leaf Senescence
Cytokinins Promote Nutrient Mobilization 21.15
Cytokinins Promote Chloroplasts Maturation 21.16

Front 20

Immunological methods in kinetin

Back 20

Immunological methods are very useful for cytokinin identification and quantification. Researchers can produce antibodies against cytokinins by injecting rabbits or mice with cytokinin ribosides conjugated to a protein. Monoclonal antibodies also have been generated that are highly specific for individual cytokinins. These antibodies can be used to quantitate the amount of a cytokinin in a sample by means of a radioimmunoassay (Weiler 1980). For cytokinin isolation, plant extracts are first fractionated, usually by high-performance liquid chromatography (HPLC), and the cytokinins in the fractions are detected and measured by means of a cytokinin radioimmunoassay, similar to the auxin radioimmunoassay described in textbook Chapter 19.
The cytokinin antibodies can also be used to isolate the hormone from extracts by immunoaffinity chromatography (Akiyoshi et al. 1983). Immunological methods hold great promise for the identification and quantification of naturally occurring cytokinins because the antibodies are highly specific and more sensitive than most bioassays (Morris et al. 1991, Nicander et al. 1993). Furthermore, these immunological methods are very rapid.

Front 21

Absorption/action spectrum in phytochrome indicates that

Back 21

red and far-red light is responsible

Front 22

Seeds germinated in the dark produce pale, spindly seedlings _______.

Name the pigment responsible.

Back 22

etiolated
pigment is : phytochrome, a protein blue pigment common in etiolated parts of plant.

Front 23

Expose a dim light to seedlings and chloroplasts will form ______.

Back 23

photomorphogenesis

Front 24

describe the molecular structure of ethylene

Back 24

C2H4

Front 25

when is ethylene produced

Back 25

throughout the life cycle of the plant

Front 26

Where is ethylene located?

Back 26

abundant in young leaves and senescing organs, ripening bananas

Front 27

ethylene synthesis starts with which amino acid? Name that cycle

Back 27

1. methionine
2. yang cycle

Front 28

etheylene is induced by ?

Back 28

stress and age, auxin & cytokinin,

Front 29

what inhibits ethylene?

Back 29

Ag and CO2

Front 30

What does ethelene do to fruit?

Back 30

ripens fruit
causes senescence (fruit death)
breakdown of cells releasing organic acids

Front 31

Name two classification of ethylene fruits

Back 31

1. climacteric - banana, apples (ripen quickly)
2. nonclimacteric - grape, cherry (dont ripen as quickly)

Front 32

Ethylene effects leafs?

Back 32

leaf epinasty - tomatoes

Front 33

What does ethylene stimulate?

Back 33

flower senescence, root hair formation, breaks seed dormancy, induces flower formation in pineapple

Front 34

what does ethylene enhance

Back 34

leaf abscission

Front 35

Yang cycle means

Back 35

ACC, may be conjugated

Front 36

Triggers abscission, stimulates ethylene production, inhibits growth and stomatal opening under envir.stress. Secondary metabolite in fungi.

Back 36

ABA

Front 37

A plant growth substance (phytohormone) involved in protion of stem elongation, mobilization of food reserves in seeds & ect processes. Its absence results in dwarfism of some plants. Family of diterpene acids made by terpenoid pathway in plastids and modified in ER & cytosol before reaching activated form.

Back 37

GA

Front 38

Biosynthesis occurs in plastids from
carotenoid intermediates

Back 38

ABA

Front 39

What inactivates ABA?

Back 39

Inactivated by oxidation or conjugation.

Front 40

How is ABA translocated?

Back 40

thrue xylem & phloem

Front 41

What are the physiological effects of ABA?

Back 41

Maintains seed and bud dormancy, functions during
water stress (maintain desiccation tolerance).
Seed Dormancy controlled by ABA and GA.
Vivipary-
Immature embryos removed
from seeds develop right
away(precociously)
Accumulates in dormant seeds and buds

Front 42

1. Prevents stomatal opening by inhibiting inward
K ion channels and plasma membrane proton pumps
2. Promotes stomatal closing by activating outward
anion channels, thus leading to activation of potassium ionse
efflux channels.

Back 42

Ways in which ABA prevents stomatal closing

Front 43

How does ABA prevent stomatal closing

Back 43

Daytime, guard cells close to keep water from being lost. K is pumped outside which keeps water concentration up inside. Stoma is now closed.

Front 44

Acid growth hypothesis"
auxin

Back 44

IAA activates H* ion ATPases; causes increases extensibility of cell wall causing it to extend.

Front 45

Phytochrome responses can be distinguished by the amount of light required

Back 45

VLFRs – very low fluence responses are nonphotoreversible

LFRs – low fluence responses are photoreversible

HIRs – high fluence responses are propotional to irradiance