why is abscissic acid called an emergency hormone in plants?
Abscissic acid acts a “stress” hormone, helping plants cope with adverse conditions that the plant might come across. An example of this is when a flower begins to wilt the abscissic acid collects in the leaves which in turn causes the stomata to close. Once the stomata is closing the transportation is reduced and prevents further water loss.
Thus abscissic acid might fulfill the role akin to adrenaline or cortisol in animals, signaling a need for emergency action under most kinds of rapidly developing environmental stress and not just water shortages.