How can seeds remain dormant for long periods?

Seeds remain dormant for long periods through a combination of physiological and structural adaptations that protect the embryo and suppress metabolic activity.

Mechanisms of Dormancy

• Dehydration: During the transition to dormancy, the embryo undergoes general dehydration, which protects it from temperature extremes and reduces metabolic activity to a minimal level.1
• Seed Coat Protection: The seed coat (testa) guards the embryo against mechanical or biological degradation. It also maintains dormancy by physically restricting the passage of water and gases, or by containing chemical inhibitors that prevent germination.21
• Metabolic Suspension: As the seed matures, cell division and protein synthesis cease, and the respiratory rate declines significantly. These processes remain suspended until the seed experiences specific environmental cues, such as abrasion, leaching of inhibitors, exposure to light, or a period of chilling.21
• After-Ripening: Some seeds require a period of time after dispersal to complete necessary embryonic development or other obscure internal processes before they are capable of germinating.2

These adaptations ensure that the plant embryo survives until conditions are optimal for growth.2