Plant Behaviors

Question 1

Tropisms

Answer 1

plant growth toward or away from an unconditioned stimulus, due to differential growth.

Question 2

heliotropism

Answer 2

• motor cells pump K+, turgor P
• maintains ideal temp./humidity
• Favors pollen development

Question 3

phototropism

Answer 3

• occurs because of cells on the shady side of the stem elongate
• a pigment related to riboflavin acts as a photoreceptor when phototropism occurs
  - auxin moves to shady side
  - shady side elongate faster than bright side

Question 4

gravitropism

Answer 4

when a plant is placed on its side, the stem grows upward, opposite of the pull of gravity.
stem w/roots grow downward. (statoliths)

Question 5

Auxin is responsible for:

Answer 5

Positive gravitropism of roots

Negative gravitropism of shoots

Question 6

Thigmotropism

Answer 6

unusual growth due to solid object contact

coiling of tendrils

occurs when entire plant responds to the presence of environmental stimuli

Question 7

Nastic (Nutational) Movements

Answer 7

don’t involve growth. aren’t dependant on stimulus direction

Question 8

Seismonastic movements

Answer 8

Touch
Shaking, or
Thermal stimulation

Question 9

Sleep movements

Answer 9

Occur daily in response to light and dark changes

Prayer Plant

Question 10

plant hormones

Answer 10

• Synthesized in one part of the plant
• Travels within phloem in response to the appropriate stimulus
• 5 commonly recognized groups
• Exert effects when bind to protein receptors

Question 11

Auxins-“Master” Plant hormones

Answer 11

-Influences structure, development, behavior
-Produced in shoot apical meristem and is found in young leaves and in flowers and fruits
-Apically produced auxin prevents the growth of axillary buds
Apical dominance
-Weak solution applied to woody cutting causes rapid growth of adventitious roots
-Promotes fruit growth
-Inhibits leaf/fruit drop
-Mediates phototropism

Question 12

Gibberellins - Gibberellic acid

Answer 12

Growth promoting hormones: cell elongation
Produced in apical buds, roots, young leaves, seed embryos
Stem elongation
Breaking of dormancy
Seed germination
Flowering
Retards leaf and fruit aging

Question 13

Ethylene

Answer 13

abscission
stimulates certain enzymes
   Leaf and flower aging, fruit ripening
  Promotes leaf and fruit drop
 Stress responses
 Seedling germination

Question 14

Abscisi Acid (ABA)

Answer 14

seed and bud dormancy
bud scale formation
stomata closure
stress response
Produced by:
	- Any “green tissue” with chloroplasts
 Monocot 
endosperm
 Roots

Question 15

Brassinosteroids

Answer 15

Promotes cell elongation
 Shoot elongation
 Stimulates xylem development
 Retards leaf drop
 Promotes stress responses
 Can be applied to protect plants from heat, 	cold, 	high salinity, herbicide injury, disease

Question 16

phenolics

Answer 16

intense flavors and smells

Question 17

2. Alkaloids -

Answer 17

Bitter-tasting molecules for defense

Question 18

Terpenoids

Answer 18

Intense smells and colors

Question 19

Polyketides

Answer 19

Chemical weapons