A Primary Result for Stomatal Closure on a Hot, Dry

Question

A primary result for stomatal closure on a hot, dry day would be
A) release of K⁺ ions to the apoplast and subsidiary cells.
B) displacement of Ca⁺⁺ ions from the thick inner walls of the guard cells.
C) disassembly of the microfibrils in the cell walls of the subsidiary cells.
D) upregulation of aquaporin synthesis.
E) downregulation of extension proteins.

Accepted Answer

Stomatal closure on hot, dry days is primarily achieved through the release of potassium ions (K⁺) from the guard cells into the apoplast and subsidiary cells. This ion efflux leads to osmotic water loss from the guard cells, causing them to lose turgor and close the stomatal pore, thereby reducing water loss from the plant.