Abscisic acid acts as an antagonist to which among the following plant growth regulator?

GAs

The correct answer is Option (3) -GAs

Abscisic acid (ABA) was discovered for its role in regulating abscission and dormancy. But like other PGRs, it also has other 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 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 GAs.