Ap Bio Chapter 39

Front 1

Etiolation

Back 1

morphological adaptations for growing in darkness

Front 2

De-etiolation

Back 2

after exposure to light, what a potato undergoes, in which shoots and roots grow normally

Front 3

Second messangers

Back 3

transfer and amplify signals from receptors to proteins that cause responses

Front 4

Hormones

Back 4

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

Front 5

Tropism

Back 5

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

Front 6

Phototropism

Back 6

a plants response to light

Front 7

Auxin

Back 7

any chemical that promotes elongation of coleoptiles

Front 8

Expansins

Back 8

enzymes that loosen the wall's fabric

Front 9

Cytokinins

Back 9

named because they stimulate cytokinesis (cell division)

Front 10

Gibberellins

Back 10

have a variety of effects, such as stem elongation, fruit growth, and seed germination

Front 11

Brassinosteroids

Back 11

chemically similar to the sex hormones of animals

Front 12

Abscisic acid (ABA)

Back 12

slows growth

Front 13

Strigolactones

Back 13

hormones that stimulate seed germination, help establish mycorrhizal associations, and help control apical dominance

Front 14

Ethylene

Back 14

produced by plants in response to stresses such as drought, flooding, mechanical pressure, injury, and infection

Front 15

Triple response

Back 15

induced by ethylene, allows a growing shoot to avoid obstacles and consists of slowing of stem elongation, a thickening of the stem, and horizontal growth

Front 16

Senescence

Back 16

programmed death of cells or organs

Front 17

Photomorphogenesis

Back 17

effects of light on plant morphology

Front 18

Action spectrum

Back 18

depicts relative response of a process to different wavelengths

Front 19

Blue-light photoreceptors

Back 19

one of the two major classes of light receptors

Front 20

Phytochromes

Back 20

the other one of the two major classes of light receptors

Front 21

Circadian rhythms

Back 21

cycles that are about 24 hours long and are governed by an internal "clock"

Front 22

Photoperiodism

Back 22

physiological response to photoperiod

Front 23

Short-day plants

Back 23

plants that flower when a light period is shorter that a cirtical length

Front 24

Long-day plants

Back 24

plants that flower when a light period is longer that a certain number of hours

Front 25

Day-neutral plants

Back 25

controlled by plant maturity, not photoperiod

Front 26

Vernalization

Back 26

a pretreatment with cold to induce flowering

Front 27

Florigen

Back 27

the flowering signal

Front 28

Virulent

Back 28

a pathogen that is one that a plant has little specific defense against

Front 29

Avirulent

Back 29

a pathogen that is one that may harm but does not kill the host plant

Front 30

Gene-for-gene recognition

Back 30

involves recognition of elicitor molecules by the protein products of specific plat disease resistance (R) genes

Front 31

Hypersensitive response

Back 31

causes cell and tissue death near the infection site, induces production of phytoalexins and PR proteins, which attack the pathogen, and stimulates changes in the cell wall that confine the pathogen

Front 32

Systemic acquired resistance

Back 32

causes systemic expression of defense genes and is a long-lasting response

Front 33

Salicylic acid

Back 33

synthesized around the infection site and is likely the signal that triggers systemic acquired resistance