Describe the role of abscisic acid in plants.

(N/A) Abscisic acid $(ABA)$ was discovered for its role in regulating abscission and dormancy.
Like other plant growth regulators $(PGRs)$,it has wide-ranging effects on plant growth and development.
It acts as a general plant growth inhibitor and an inhibitor of plant metabolism.
$ABA$ inhibits seed germination.
$ABA$ stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses.
Therefore,it is also called the stress hormone.
$ABA$ plays an important role in seed development,maturation,and dormancy.
By inducing dormancy,$ABA$ helps seeds to withstand desiccation and other factors unfavourable for growth.
In most situations,$ABA$ acts as an antagonist to gibberellins $(GAs)$.