Final answer:
b) rest due to lack of cold The most common type of seed dormancy is rest due to lack of cold, mediated by the hormone abscisic acid (ABA), which ensures that seeds only germinate under favorable conditions after a cold period.
Step-by-step explanation:
The most common type of seed dormancy is rest due to lack of cold, often referred to as physiological dormancy. This type of dormancy is induced by the hormone abscisic acid (ABA), which blocks germination and promotes the synthesis of storage proteins. Plants, especially those in temperate climates, need a period of cold before germination to prevent seeds from sprouting too early during warm spells in winter. As ABA levels decrease over the winter, seeds are released from dormancy, allowing germination when conditions are more favorable in the spring. This mechanism also promotes the development of winter buds and is essential for the survival of the plant through periods when conditions are not suitable for growth.
Seed dormancy is a period of temporary inactivity in seed germination. The most common type of seed dormancy is rest due to lack of cold. Plants adapted to temperate climates require a long period of cold temperature before seeds germinate. This protects them from sprouting too early during unseasonably warm weather. When conditions are favorable, the seed will break dormancy and germinate.