When the two guard cells surrounding a stoma lose water and collapse against each other, the stoma closes, a response mediated by which hormone?
A)abscisic acid
B)ethylene
C)auxin
D)cytokinin
E)gibberellin

Question

Quizplus · Accepted Answer

The hormone that mediates the closure of stomata in response to water loss by the two surrounding guard cells is abscisic acid. This hormone induces the closing of the stomata to conserve water and prevent further water loss. The other hormones listed (ethylene, auxin, cytokinin, gibberellin) do not have a direct role in the regulation of stomatal closure in response to water loss.

When the Two Guard Cells Surrounding a Stoma Lose Water