Describe how closing the stomata helps a wilting plant to recover, and explain why a plant wilts in the first place.

Cambridge International IGCSE Biology (0610) — 8.3 Transpiration · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

1. Wilting occurs when water loss by transpiration exceeds water uptake by the roots.
2. The excess loss of water causes water to move out of the cells, reducing turgor pressure and making the cells flaccid.
3. When the stomata close, water vapour can no longer diffuse out of the leaf, so the rate of transpiration falls.
4. With less water lost, uptake can exceed loss, allowing cells to regain turgor and the plant to recover.

Examiner tips

  • Use the exact terms ‘turgor pressure’, ‘flaccid’, ‘transpiration’, and ‘stomata’. Show the cause–effect chain: loss of water → loss of turgor → wilting, then stomatal closure → reduced transpiration → recovery. Keep each point concise and directly linked to the marks.

Common mistakes

  • Confusing stomatal closure with cuticle function. Using vague phrases like ‘less water loss’ without mentioning transpiration. Failing to mention turgor pressure or flaccid cells.

Mark scheme (4 marks)

  1. Wilting occurs because water loss via transpiration is greater than water uptake by the roots
  2. Water moves out of cells, causing loss of turgor pressure / cells become flaccid
  3. Closing the stomata prevents water vapour diffusing out of the leaf
  4. This reduces the rate of transpiration, allowing water uptake to exceed water loss so cells regain turgor

Key terms in this question

stomata · wilting

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