In the acid growth hypothesis, auxin causes

  1. cells to divide faster
  2. stomata to close
  3. the cell wall to thicken
  4. proton pumps to acidify the cell wall, loosening it
Answer

D) proton pumps to acidify the cell wall, loosening it

Low pH activates expansins. AS & A Level Biology · Topic 15 Control and Coordination · 15.2 Control and coordination in plants

Biology MCQ · More A Level Biology: Control and coordination MCQs · Practise