[Campbell Biology P.13] According to the 'Gas Exchange' section and its accompanying diagra... | Practice Question

According to the 'Gas Exchange' section and its accompanying diagram, which of the following events directly leads to the opening of a plant stoma?

  • A: Active transport of K+ out of the guard cell.
  • B: Inward movement of K+ driven by a membrane potential generated by H+ efflux.
  • C: Osmotic efflux of water from the guard cell.
  • D: Direct transport of H2O into the guard cells via aquaporins.

Explanation

The 'Gas Exchange' section states: 'Active transport of H+ out of a guard cell generates a voltage membrane potential that drives inward movement of K+. This uptake of K+ by guard cells triggers an osmotic influx of water that changes cell shape, bowing the guard cells outward and thereby opening the stoma.'