Control System in Plants

Question 1

Abscisic Acid (ABA)

Answer 1

slows growth; closes stomata during dry spells; helps maintain seed dormancy; promotes leaf aging

Question 2

Abscission

Answer 2

the separation of fruits, flowers or even leaves from plants at specialized separation layers.

Question 3

Acid Growth Hypothesis

Answer 3

when exposed to auxin, susceptible cells excrete protons into the wall (apoplast) at an enhanced rate, resulting in a decrease in apoplastic pH.

Question 4

Adventitious Roots

Answer 4

roots that form from nonroot tissues

Question 5

Amyloplast

Answer 5

a colorless plant plastid that forms and stores starch.

Question 6

Apical Dominance

Answer 6

the hormonal inhibition of axillary buds by a terminal bud.

Question 7

Auxin

Answer 7

stimulate stem elongation; affect root growth, differentiation, branching; development of fruit; apical dominance; photo and gravitropism; prevent leaf abscission

Question 8

Biological clocks

Answer 8

internal timekeepers that control circadian rhythms

Question 9

Circadian Rhythm

Answer 9

An innate biological cycle of about 24 hours that is not controlled by any known environmental variable

Question 10

Coleoptile

Answer 10

cylindrical organs that ensheath the first leaf and shoot apex in grass seedlings.

Question 11

Cytokinins

Answer 11

hormones produced in actively growing tissues—particularly in roots, embryos, and fruits—that promote cytokinesis, or cell division, and cell differentiation. They also prevent the aging of leaves and flowers by inhibiting protein breakdown

Question 12

Day neutral plants

Answer 12

plants form flowers regardless of day length

Question 13

Ethylene

Answer 13

promotes fruit ripening and leaf abscission; opposes some auxin effects; promotes root formation and flowers

Question 14

Foolish seedlings

Answer 14

disease is characterized by increased internodal length and low seed production in rice plants.

Question 15

Gibberellins

Answer 15

promote bud development; stem elongation, and leaf growth; stimulate flowering, fruit development and seed germination

Question 16

Gavitropism

Answer 16

he directional growth of a plant in response to gravity—explains why, no matter how a seed lands on the ground, shoots grow upward (negative) and roots grow downward (positive)

Question 17

Herbivores

Answer 17

plant-eaters

Question 18

Hormone

Answer 18

a chemical signal produced in one part of the body and transported to other parts, where it acts on target cells to change their functioning

Question 19

Long-day plants

Answer 19

such as spinach, lettuce, radishes, and many cereal grains, usually flower in late spring or early summer, when light periods lengthen

Question 20

Nastic Movement

Answer 20

The non-directional movement of plants in response to a stimulus (e.g. humidity, temperature)

Question 21

Photomorphogenesis

Answer 21

a developmental process in plants in which the incident light determines the growth of the plant.

Question 22

Photoperiod

Answer 22

The environmental stimulus plants most often use to detect the time of year

Question 23

Phototropism

Answer 23

The growth of an organ in response to light

Question 24

Phytochrome

Answer 24

proteins with a light-absorbing component.

Question 25

precocious germination

Answer 25

involves the germination of seeds while still on the parent plant

Question 26

Short-day plants

Answer 26

generally flower in late summer, fall, or winter, when light periods shorten.

Question 27

Signal Transduction

Answer 27

the process by which a chemical or physical signal is transmitted through a cell as a series of molecular events,

Question 28

Solar tracking

Answer 28

when a plant follows the movement of the sun during the day.

Question 29

Statolith

Answer 29

sediments at the bottom of the gravisensing cells, the statocytes

Question 30

Systemic acquired resistance

Answer 30

Upon infection with necrotizing pathogens many plants develop an enhanced resistance to further pathogen attack

Question 31

thigmomorphogenesis

Answer 31

the response by plants to mechanical sensation (touch) by altering their growth patterns.

Question 32

Thigmotropism

Answer 32

directional growth in response to touch, is illustrated when the tendril of a pea plant contacts a wire and coils around it for support

Question 33

Triple response

Answer 33

The application of low levels of ethylene to etiolated seedlings results in seedlings with an exaggerated curvature of the apical hook.

Question 34

Tropism

Answer 34

Any growth response that results in plant organs curving toward or away from stimuli