Question 7c
When leaf mesophyll cells lose water, some ABA stored in the chloroplasts is released into the apoplast and moves through the transpiration stream to reach guard cells. Explain why this is beneficial when the leaf is dehydrated.
- In conditions of dehydration, the movement of ABA to the guard cells through the apoplast pathway is advantageous because ABA triggers the closure of stomata.
- By closing the stomata, water loss through transpiration is reduced, helping the plant conserve water and prevent further dehydration.