chapter 31

Question 1

plant hormones

Answer 1

chemical signals that modify or control one or more specific physiological process within a plant

Question 2

tropism

Answer 2

any response resulting in curvature of organs towards or away from a stimulus

Question 3

phototropism

Answer 3

a plants response to light

Question 4

auxin

Answer 4

mobil chemical substance and cause signal to move plant towards the sunlight

Question 5

auxin is produced in…

Answer 5

shoot tips and transported down the stem

Question 6

auxin causes…

Answer 6

cell elongation and increase in the activity of proton pumps to loosen the cell wall

Question 7

proton pumps

Answer 7

lower the pH in the cell wall, activating expansions which loosen the walls cellulose connections

Question 8

cytokinins

Answer 8

stimulate cytokinesis (cell division)

Question 9

cytokinins and auxins work together to…

Answer 9

control cell division and differentiation

Question 10

gibberellins

Answer 10

stimulate fruit growth and seed germination

Question 11

abscisic acid (ABA)

Answer 11

contributes to seed dormancy and drought tolerance

Question 12

seed dormancy

Answer 12

ensures that the seed will germinate only in optimal conditions

Question 13

drought tolerance

Answer 13

cause stomata to close

Question 14

ethylene

Answer 14

associated with apoptosis the programmed destruction of cells and triggers ripening

Question 15

leaf abscission

Answer 15

the process that occurs in autumn when a leaf falls

Question 16

photomorphogenesis

Answer 16

key events in plant growth/development triggered by light

Question 17

photochromes

Answer 17

photoreceptors that absorb mostly red light

Question 18

photochrome conversion

Answer 18

marks sunrise/sunset which makes biological clocks possible in plants

Question 19

photoperiod

Answer 19

relative lengths of night and day in the environment stimulus plant used most often to detect time of year

Question 20

short-day plants

Answer 20

plants that flower when a light period is shorter than a critical length. critical night length sets a minimum hours of darkness

Question 21

long-day plants

Answer 21

plants that flower when a light period is longer than a certain number of hours. critical night length sets a maximum hours of darkness

Question 22

day-neutral plants

Answer 22

flowers is controlled by plant maturity not photoperiod

Question 23

critical night length

Answer 23

responses to photoperiod are actually controlled by night length not day length

Question 24

because of immobility…

Answer 24

plants must adjust to a range of environment and physiological mechanisms. gravity, mechanical stimuli, environmental stress

Question 25

gravitropism

Answer 25

response to gravity

Question 26

thigrmomorphogensis

Answer 26

change in form that results from mechanical disturbance

Question 27

thigmotropism

Answer 27

growth in response to touch. in vines/climbing plants

Question 28

abiotic

Answer 28

nonliving environmental stress (drought, flooding, heat/cold)

Question 29

biotic

Answer 29

living environmental stress (herbivores/pathogens)