Lecture 19 Plant Hormones

Question 1

Bark is made of entirely dermal tissue (T/F)

Answer 1

F, Phloem in the bark is vascular tissue

Question 2

Why might spring wood be darker than summer wood

Answer 2

More water in summer-wood causing the spring-wood to condense and be denser, thus darker

Question 3

Girdling

Answer 3

Phloem is removed, cutting the roots off from sugar production from photosynthesis, roots die and tree dies

Question 4

Environmental stimuli for plants

Answer 4

– Light
– Day/night length
– Gravity
– Herbivores and pathogens
– Stress (heat, cold, drought, flooding, etc)

Question 5

How do plants know when to shed leaves?

Answer 5

Day length

Question 6

Plant hormones

Answer 6

– Hormones can affect cells where they are
produced
– Non-protein compounds

Question 7

What is de-etiolation

Answer 7

formation of leaves and chloroplasts in response to light, also elongation of roots and stems.

Question 8

Phototropism

Answer 8

growth towards light source

Question 9

What is the relevant hormone for photopropism

Answer 9

Auxin

Question 10

Gibberellins

Answer 10

increase internodes, encourages elongation

Also induces fruit growth

Question 11

Cytokins

Answer 11

Stimulate plant cell division and promote later bud growth, slow aging of plants
also encourage lateral growth

Question 12

Auxin

Answer 12

Stimulates cell elongation, regulates branching and organ bending

Question 13

Ethylene

Answer 13

mediates fruit ripening and triple response

Question 14

abscisic acid (ABA)

Answer 14

promotes stomatal closure in response to drought, also promotes seed dormancy

Question 15

de-etiolation

Answer 15

changes in plant due to light

Question 16

morphological adaptations for growing in darkness is

Answer 16

etiolation

Question 17

triple response

Answer 17

allows growing stems to avoid obstacles