Module 2: Plant Hormones

Question 1

group of unrelated chemical substances that affect plant growth and development

Answer 1

phytohormones

Question 2

responsible for cell elongation

Answer 2

auxins

Question 3

stimulates proton pumps & lowers pH in cell walls; activates expansin enzymes which loosen the cellulose microfibrils of the cell walls and allows cells to expand/elongate

Answer 3

auxins

Question 4

stimulate lateral root formation

Answer 4

auxins

Question 5

acts as an herbicide in very high doses; stimulates ethylene production

Answer 5

auxins

Question 6

inhibition of lateral bud formation by the apical bud

Answer 6

apical dominance

Question 7

favors elongation of the stem as opposed to branch formation

Answer 7

auxins

Question 8

promote plant cell division; produced in actively growing tissues (root apical meristem, embryo, fruit)

Answer 8

cytokinins

Question 9

____ auxin to ____ cytokinin ratio will result to root formation

Answer 9

high auxin to low cytokinin ratio

Question 10

____ auxin to ____ cytokinin ratio will result to shoot formation

Answer 10

low auxin to high cytokinin ratio

Question 11

equal amount of the auxins and cytokinins will give rise to _____

Answer 11

callus tissue

Question 12

promotes axillary bud growth

Answer 12

cytokinins

Question 13

delay senescence in leaf tissues and other organs by stimulating RNA/protein synthesis and inhibiting protein breakdown

Answer 13

cytokinins

Question 14

stimulate shoot elongation, seed germination, and fruit and flower maturation

Answer 14

gibberellins

Question 15

induce leaf and stem growth; promote internode elongation

Answer 15

gibberellins

Question 16

enzymes that loosen the cellulose microfibrils of the cell walls and allows cells to expand/elongate

Answer 16

expansins

Question 17

promote fruit development; used to increase the size of fruits

Answer 17

gibberellins

Question 18

released after seed imbibes water; triggers breaking of dormancy

Answer 18

gibberellins

Question 19

stimulate synthesis of amylases that mobilize stored nutrients to the scutellum

Answer 19

gibberellins

Question 20

accumulates as a response to stressful environmental conditions

Answer 20

abscisic acid

Question 21

inhibits stem elongation and induces dormancy in lateral buds

Answer 21

abscisic acid

Question 22

induces dormancy in seeds by blocking germination and promoting the synthesis of proteins which help the seed withstand dehydration

Answer 22

abscisic acid

Question 23

accumulates in leaves and result to closure of stomata; signals in roots that warn the plant of water shortage

Answer 23

abscisic acid

Question 24

associated with fruit ripening, flower wilting, and leaf fall

Answer 24

ethylene

Question 25

regulates both growth and senescence depending on concentration, timing of application, and plant species

Answer 25

ethylene

Question 26

promotion of fruit ripening; stimulates the conversion of starch and acids to sugars

Answer 26

ethylene

Question 27

triggers leaf and fruit abscission, flower fading and dropping

Answer 27

ethylene

Question 28

steroids similar to cholesterol and the sex hormones of animals

Answer 28

brassinosteroids

Question 29

actions similar to that of auxins

Answer 29

brassinosteroids

Question 30

play a role in plant defenses against herbivores and pathogens

Answer 30

jasmonates

Question 31

xylem-mobile chemicals that stimulate seed germination, suppress adventitious root formation, help establish mycorrhizal associations, and control apical dominance

Answer 31

strigolactones