Bio: Responding to the environment- Plants

What does abscisic acid actually do?
Does it work antagonistically to both cytokinins and gibberellins?
My textbook says Abscisic Acid works in combination with Auxins, so does that mean it works in synergy with Auxins?
Thanks

Abscisic acid is a plant hormone which performs a variety of roles. It is up-regulated during stress responses in order to elucidate defense mechanisms. More to your point, it is a well known inhibitor of seed germination in seeds and is vital for maintaining seed dormancy. Abscisic acid is generally believed to act antagonistically to gibberellins and cytokinins, since they are promoters of dormancy release. Auxins typically promote plant growth, and abscisic acid works in combination with a large number of plant hormones, but this does not mean it works synergystically with growth promoters.

Sources: Role of Abscisic Acid in Plant Dormancy.
Early abscisic acid signal transduction mechanisms: newly discovered components and newly emerging questions