Chapter 39 Communcation Chemical Signals

Front 1

chemical signals that regulate and coordinate metabolism, growth, and development; the link between the receipt of information by a sensory receptor and the plant's response to that information

Back 1

hormones

Front 2

these hormones may be synthesized in one part and transported elsewhere, or may be active at the site of synthesis

Back 2

plant hormones

Front 3

hormones may elicit different responses in different ______ or at different __________ stages

Back 3

tissues, developmental

Front 4

first plant hormone identified, indole acetic acid (IAA), principal production sites include shoot apical meristems, young leaves, and developing fruits and seeds; IAA is synthesized in shoots and transported to roots

Back 4

auxins

Front 5

Where is the light responsible for triggering phototropism sensed?

Back 5

coleoptile tip

Front 6

the phototropic signal is a what? (electrical message, mechanical activity, chemical); it can diffuse

Back 6

chemical

Front 7

this hormone was capable of producing the bending response in the absence of light by elongating cells

Back 7

auxin

Front 8

this hormone is prevented from migrating from one side of the tip to the other; each side of agar block receives same amount of the hormone; it can however migrate from one side of the tip to the other before diffusing into agar

Back 8

auxin

Front 9

what does asymmetrical distribution of auxin results from?

Back 9

lateral redistribution in tip, it is the chemical cue responsible for gravitropism in roots

Front 10

is polar transport of auxin multi or uni directional in shoots?

Back 10

unidirectional

Front 11

when auxin arrives in the root is which way is it distributed toward epidermal cells and to the zone of elongation?

Back 11

outward towards epidermal cells and upward to the zone of elongation

Front 12

this hormone is stimulatory in shoots and inhibitory and stimulatory in roots in regards to cell elongation

Back 12

auxin

Front 13

when a shoot tip is removes, what happens to the lateral buds?

Back 13

they are not suppressed

Front 14

this hormone initiates the development of lateral and adventitious roots and initiates differentiation of vascular tissue

Back 14

auxin

Front 15

when this hormone is produced by seeds it promotes fruit development

Back 15

auxin

Front 16

this hormone promotes cell division, is produced in actively dividing tissues, seeds, buds, fruits, leaves, and root tipes, is synergistic with auxin, and is important use in tissue culture and biotechnology

Back 16

cytokinins

Front 17

when a callus is treated with auxin and cytokinin it develops....

Back 17

shoots and roots

Front 18

when there is a transfer to medium with high auxin to cytokinin ratio (>10:1) what forms?

Back 18

the roots

Front 19

when there is a transfer to medium with low auxin to cytokinin ratio (<10:1) what forms?

Back 19

the shoots

Front 20

when there are equal amounts of auxin and cytokinin what forms?

Back 20

callus but it remains undifferentiated

Front 21

this hormone stimulates cell division and elongation, breaks dormancy in seeds, promotes germination, and induces flowering; there are more than 125 kinds identified, most plants have more than 10 different kinds

Back 21

gibberellins

Front 22

seed germination is known as...

Back 22

malting

Front 23

seed flowering is known as...

Back 23

bolting

Front 24

this hormone was originally thought to promote abscission (dropping) of leaves, it induces stomatal closure in response to water stress, and maintains dormancy in seeds

Back 24

abscisic acid (ABA)

Front 25

stomata open in response to what color light?

Back 25

blue light

Front 26

stomata close in response to what?

Back 26

ABA abscisic acid

Front 27

Can roots communicate with shoots?

Back 27

yes... dry roots signal the shoot and cause stomata to close, even though leaves are receiving sufficient water

Front 28

this is the only gaseous hormone that is involved in 3 aspects of senescence (aging) in plants, fading of flowers, abscission of leaves, and fruit ripening

Back 28

ethylene

Front 29

this response is induced only in the presense of a threat, and it responds to signals from hormones

Back 29

induced defenses

Front 30

this anti-herbivore defense molecule leads to production of insecticides

Back 30

systemin

Front 31

this anti-herbivore defense molecule recruits help from other organisms

Back 31

pheromones

Front 32

wound response hormone produced by herbivore damaged cells; initiates synthesis of jasmonic acid in undamaged cells which in turn activates the production of proteinase inhibitors which block the enzymes responsible for protein digestion (found in the mouths and stomachs of animals)

Back 32

systemin

Front 33

chemical messengers synthesized by an individual and released into the environment that elicit a response from a different individual; some plants produce these in response to attack by caterpillars that attract parasitoid wasps

Back 33

pheromones

Front 34

an organism that is free-living as an adult, but parasitic in its larval stage

Back 34

parasitoid