Final answer:
Seed dormancy is adaptive for plant species as it allows offspring to germinate under optimal conditions, protects seeds during challenging environmental periods, and contributes to species dispersal through time and space. The hormone ABA is essential in inducing this dormancy. The success of seed plants owes much to these adaptive advantages.
Step-by-step explanation:
Seed dormancy is adaptive for plant species because it allows for the strategic dispersion of offspring through time, ensuring that plants germinate and grow in conditions favorable to their survival. Dormant seeds are capable of waiting for the proper environmental cues before germinating, which can span months, years, or even decades. This ability to delay germination protects seeds from sprouting during periods that are not conducive to plant growth, such as unseasonably warm weather during winter times or periods of insufficient moisture.
Additionally, seeds contain a protective coat and a store of nutrients which give the embryo a substantial advantage once it begins to grow. The hormone abscisic acid (ABA) plays a crucial role in inducing dormancy and blocking germination until conditions improve. It not only prevents premature germination but also promotes the synthesis of storage proteins, and the development of winter buds, which help reduce water loss through stomata during dry seasons. Moreover, having a dormant phase allows seeds to avoid competition with parent plants and increases the chances of dispersal to a variety of geographical locations.
The evolutionary benefits of seeds, such as protection, nourishment, and delayed germination, have made seed plants incredibly successful in colonizing a range of terrestrial environments. This success is exemplified by the proliferation of seed plants relative to seedless varieties in various ecosystems across the globe.