4/30 lecture

Question 1

amyloplasts (def)

Answer 1

plastids specialized for starch storage

Question 2

How do amyloplasts effect auxin distribution?

Answer 2

they sink towards gravity

Question 3

How are roots and shoots effected?

Answer 3

• auxin response in root gravitropism and shoot phototropism is oppostive
• roots are much more sensitive to auxin concentration than shoots

Question 4

What 3 things do cytokinins promote?

Answer 4

1. cell division via mitosis
2. axillary bud growth
3. sink-strength

Question 5

What 2 things do cytokinins inhibit?

Answer 5

1. cell division via mitosis

2. leaf senescence

Question 6

What is the name of the enzyme that breaks down cytokinin?

Answer 6

cytokinin oxidase

Question 7

Where are cytokinins produced

Answer 7

root apical meristem

Question 8

How are cytokinins transported to shoots?

Answer 8

Through xylem!

Question 9

What happens to cytokinin when N is scarce?

Answer 9

production is reduced

Question 10

cytokinin-mediated responses

Answer 10

1. promote cell division in shoot apical meristem
2. inhibit cell division root apical meristem
3. axillary bud growth
4. balance of root and shoot growth
5. delay senescence
6. promote sink strength

Question 11

Overexpression of cytokinins ______ the natural onset of senescence

Answer 11

delay

Question 12

What are transported preferentially to cytokinin-treated tissues?

Answer 12

labeled amino acids

Question 13

What are gibberellins

Answer 13

another regulator of plant growth

Question 14

Where does gibberellins synthesis occur?

Answer 14

Starts in plastids and finished in the ER and cytosol in seeds, shoot tips and nodes

Question 15

what 4 things do gibberellins promote?

Answer 15

1. stem growth (elongation and cell division)
2. flowering in LD plants
3. seed germination
4. fruit set