Coordination and Response:Plants

Question 1

What is auxin?

Answer 1

• a growth hormone
  - controls direc. of growth
  - of roots or stems

Question 2

Where is auxin produced?

Answer 2

• In the meristem

- In the tip of the shoot

Question 3

What does auxin trigger?

Answer 3

• growth of the MAIN STEM of the plant

- INHIBITS growth of side shoots

Question 4

Which part of the plant is positively phototrophic?

Answer 4

-shoots

(grow TOWARDS light source)

Question 5

Which part of the plant is positively geotropic?

Answer 5

• roots
  
  • grow down
    
    • IN THE DIRECT. of gravity

Question 6

How does auxin cause the shoots to grow towards the light source in unilateral light?

Answer 6

• Auxin CONCENTRATES on shady side
• cells on shad. side grow FASTER
• UNEVEN growth
• Stretches/curves plant 2 light

Question 7

How does the shoot grow in darkness/uniform light?

Answer 7

• Auxin DIFFUSES down the stem
  - EQUAL RATES both sides
• growth on both EQUAL
• grows straight up

Question 8

What happens when the tips of a plant are removed?

Answer 8

-The STEMS do not grow longer