Final answer:
The decrease in abscisic acid (ABA) levels is responsible for releasing seeds from dormancy, allowing them to germinate when environmental conditions are suitable.
Step-by-step explanation:
The hormone responsible for releasing seeds from dormancy is abscisic acid (ABA). When environmental conditions are adverse for seed germination, ABA levels increase, signaling the seeds to enter or continue dormancy. Conversely, when conditions improve, ABA levels decrease, thereby lifting the dormancy and allowing the seeds to germinate. Gibberellins, another group of plant hormones, have the opposite effect; they promote germination and growth. Therefore, in an experiment to release seeds from dormancy, a plate with a decrease in ABA or an application of gibberellins would likely show the highest rate of germination.