Final answer:
Hard seed coat dormancy is a form of physical dormancy, with seeds awaiting favorable conditions to germinate. Scarification methods are used to break this dormancy. Abscisic acid (ABA) induces dormancy, so in experiments, plates without ABA would likely show higher germination rates.
Step-by-step explanation:
The type of dormancy associated with hard seed coat is known as physical dormancy. This is a mechanism by which the seed remains inactive and is prevented from germinating until conditions are favorable. The hard seed coat serves as a barrier to moisture and gas exchange, thereby delaying germination. In many species, this coat must be degraded or broken down, a process known as scarification, before the seed can germinate. Heat, mechanical action, or passage through an animal's digestive tract can serve as natural scarification methods.
Considering the role of hormones, abscisic acid (ABA) is known to induce dormancy by inhibiting germination. Therefore, in an experiment to stimulate seed germination, the plate with abscisic acid is unlikely to show the highest germination rate. Seeds require the breakdown of ABA, or the presence of other hormones like gibberellins, to overcome dormancy and begin germination when environmental conditions improve.