Plant Signaling

Question 1

What is de-etiolation?

Answer 1

Greening

Question 2

Auxins: production site and action

Answer 2

Site: Shoot meristem/young leaves
Action: Stem elongation

Question 3

Cytokinins

Answer 3

Site: Roots
Action: Cell division

Question 4

Gibberellins

Answer 4

Site: Meristems, leaves and seed
Action: Stem elongation and reproduction

Question 5

Brassinosteroids

Answer 5

Site: All plant tissues
Action: Cell division, xylem differentiation

Question 6

Abscisic acid

Answer 6

Site: All plant tissues
Action: Inhibits growth, promotes dormancy

Question 7

Ethylene

Answer 7

Site: All plant tissues
Action: Fruit ripening and plant senescence, triple response

Question 8

Phototropism

Answer 8

Movement or growth of a plant in response to unidirectional light (e.g., heliotropism by sunflowers)

Question 9

Gravitropism

Answer 9

Movement or growth of a plant in response to gravity

Question 10

Thigmotropism

Answer 10

Movement or growth of a plant in response to contact with an object

Question 11

Thigmonasty

Answer 11

Plant folds when touched in a unidirectional manner

Question 12

Nastic movement

Answer 12

Reversible or temporary movements in response to a stimulus (regardless of stimulus direction)

Question 13

Circadian rhythm

Answer 13

A 24-hour cycle of response in plants

Question 14

Phytochrome

Answer 14

A blue-green pigment that exists in two forms and signals the light switch in de-etiolation

Question 15

Vernalization

Answer 15

Refers to a low-temperature stimulation of flowering (stratification in seeds is similar)

Question 16

Statoliths

Answer 16

Amyloplasts that move in the plant root and shoot tip to help in responding to gravity

Question 17

Triple Response

Answer 17

The slowed elongation, thickening and turning of an underground shoot in response to an obstacle