Module 2: Plant Responses to the Environment

Question 1

cells found near the vascular tissue in shoots, and in the root cap columella in roots

Answer 1

statocytes

Question 2

starch-filled organelles in statocytes; settle at the bottom of statocyte in direction of gravity

Answer 2

statoliths

Question 3

auxin levels are higher on the lower sides of roots and shoots

Answer 3

lateral auxin gradient

Question 4

directional growth in response to touch or physical contact with a solid object

Answer 4

thigmotropism

Question 5

response towards the touch stimulus

Answer 5

positive thigmotropism

Question 6

response away from the touch stimulus

Answer 6

negative thigmotropism

Question 7

changes in the form of the plant body due to mechanical stress

Answer 7

thigmomorphogenesis

Question 8

makahiya leaves; no matter where the leaf or leaflet is touched, the stimulus is propagated through neighboring leaflets

Answer 8

thigmonastism

Question 9

specialized motor organs located at the joints of the leaf

Answer 9

pulvini

Question 10

Folding in makahiya results from ___

Answer 10

rapid loss of turgor in cells within pulvini

Question 11

environmental dynamics fall out of the optimal limit, changes in metabolism and functioning occur

Answer 11

stress

Question 12

under this condition, plants will increase the saturated fatty acid proportion in their cell membranes

Answer 12

high temperature

Question 13

under this condition, plants will increase the unsaturated fatty acid proportion in their cell membranes

Answer 13

low temperature

Question 14

molecular chaperones; prevent aggregation of denatured proteins; promote renaturation of aggregated protein molecules

Answer 14

heat-shock proteins

Question 15

under this condition, plants will close their stomata to reduce stomatal conductance and water-loss due to transpiration

Answer 15

high temperature

Question 16

under this condition, plants will accumulate solutes like sugars – sucrose, glucose, and fructose, within their cells.

Answer 16

low temperature

Question 17

plants respond to moderate salt stress by increasing internal levels of solutes like _____ & _____ that are well-tolerated at high concentrations

Answer 17

proline and glycine

Question 18

can ameliorate some effects of salt stress by facilitating potassium uptake through the regulation of ion transporters

Answer 18

calcium

Question 19

salt-resilient

Answer 19

halophytes

Question 20

not salt-resilient

Answer 20

glycophytes

Question 21

have salt glands in their stems and leaves

Answer 21

recretohalophytes

Question 22

specialized epidermal glands that take up excess salt from neighboring tissues and excrete it onto the plant surface

Answer 22

salt glands

Question 23

general plant response to drought stress

Answer 23

synthesis of abscisic acid

Question 24

soil bacterium that is reported to induce drought tolerance in Arabidopsis; increased nitrogen fixation by rhizobium and increased growth of the bean plant

Answer 24

Paenibacillus polymyx

Question 25

appears as swelling of tissues at the stem base during flooding; aid in the downward diffusion of oxygen and potential venting of toxic compounds

Answer 25

hypertrophic growth

Question 26

defense against both herbivores and pathogens; toxic and lethal to other organisms; can repel predators with noxious odors, repellant tastes, or allergenic characteristics

Answer 26

secondary metabolites

Question 27

mechanism that enables plants to sense the presence of pathogens and activate defense responses to pathogen attacks

Answer 27

systemic acquired resistance (SAR)

Question 28

unique set of light-sensitive proteins

Answer 28

photoreceptors

Question 29

non-protein, light-absorbing pigment

Answer 29

chromophore

Question 30

class of photoreceptors that sense red and far-red light

Answer 30

phytochromes

Question 31

growth and development of plants in response to light

Answer 31

photomorphogenesis

Question 32

Exposure to ____ triggers the elongation of stems and petioles in search of light.

Answer 32

far-red light

Question 33

Exposure to ____ enhances lateral growth and branching.

Answer 33

red light

Question 34

intrinsic, timekeeping, molecular mechanism that allows plants to coordinate physiological activities over 24-hour cycles

Answer 34

circadian (or biological) clock

Question 35

collective term for the biological responses of plants to variations in the relative lengths of dark and light periods

Answer 35

photoperiodism

Question 36

period of light-exposure (night length)

Answer 36

photoperiod

Question 37

plants that flower after a minimum number of consecutive long nights

Answer 37

short-day plants

Question 38

plants that flower after a minimum number of consecutive short nights

Answer 38

long-day plants

Question 39

(night length, plant type)

high Pfr : low Pr

Answer 39

short night, long-day plant

Question 40

(night length, plant type)

low Pfr : high Pr

Answer 40

long night, short-day plant

Question 41

detect presence of pathogen; result in cascade of responses

Answer 41

membrane-bound receptors

Question 42

detect effector molecules; lead to expression of pathogen-related genes and rapid-programmed cell death

Answer 42

resistance proteins

Question 43

released to attract parasite that kills herbivore

Answer 43

volatiles