plant hormones

Question 1

properties of hormones

Answer 1

location produced, location used, how much is needed, stimulatory or inhibitory

Question 2

how hormones work

Answer 2

altering gene expression, triggering cell division, cause or allow cell elongation,

Question 3

cell elongation

Answer 3

occurs by breaking hemicellulose linkers, allowing the cell wall to expand

Question 4

Arabidopsis thaliana

Answer 4

model organism for plant research, originates in Europe as a spring annual, is relatively small, rapid generation time (seed to seed in 6 weeks), has a very small genome

Question 5

auxins

Answer 5

first discovered plant hormone, responsible for tropisms, trigger growth of branch roots and adventitious roots, promote apical dominance, triggers fruit development when produced in seeds signaling the ovary to become a fruit, lethal in high doses

Question 6

phototropism

Answer 6

occurs in shoot tips, studied by Darwin, Auxin is produced in shoot tips in response to light and they move down the stem to accumulate on the shady side of the plant causing elongation

Question 7

gravitropism

Answer 7

negative in shoots, positive in roots, caused by statoliths and auxin, in roots auxin gathers where amyloplasts are preventing elongation, in shoots auxin gathers where amyloplasts are causing elongation in the opposite direction

Question 8

statoliths

Answer 8

structures used to sense gravity in plants, in roots amyloplasts are statoliths in the root caps causing them to fall due to gravity

Question 9

adventitious roots

Answer 9

roots that grow off of stems

Question 10

apical dominance

Answer 10

auxin inhibits growth of axillary buds causing the plant to grow tall rather than branching

Question 11

cytokinins

Answer 11

promote cell division when in equal concentrations with auxin, causes callus tissues, can overcome apical dominance causing branching

Question 12

callus tissue

Answer 12

large clumps of undifferentiated tissues

Question 13

tissue cultures

Answer 13

single undifferentiated cell is exposed to equal concentrations of cytokinin and auxin creating callus tissue, expose this tissue to high cytokinin and low auxin causing stem formation, high auxin causes root formation

Question 14

gibberelins

Answer 14

promote whole shoot elongation, induce seed germination by breaking down the endosperm, induce bolting, stimulates fruit development from inside seeds, increase the size of fruits

Question 15

bolting

Answer 15

flowering

Question 16

Norman Borlaug

Answer 16

worked with gibberellins in wheat during the green revolution, discovered and bred dwarf varieties lacking gibberellins producing a higher volume of wheat grains per plant

Question 17

ethylene

Answer 17

triggers ripening of fruits by causing color change and the conversion of starch to sugars, causes leaf and fruit abscission by breaking down pectin,

Question 18

ethylene triple response

Answer 18

in normal plants, reduces stem elongation and grows thicker stems, and causes stem curvature, triggered in nature when plants hit an object during sprouting

Question 19

abscisic acid (ABA)

Answer 19

triggers and maintains bud and seed dormancy and can promote stomatal closures under drought stressors