Seed dormancy is defined as a state in which seeds are prevented from germinating even under environmental conditions normally favorable for germination. These conditions are a complex combination of water, light, temperature, gasses, mechanical restrictions, seed coats, and hormone structures.
The main reason for these conditions is that they require a period of rest before being capable of germination. These conditions may vary from days to months and even years. These conditions are the combination of light, water, heat, gases, seed coats, and hormone structures. There are certain major causes for That. Listed below are the few reasons for seed dormancy.
- Light and Temperature
- The hardness of Seed Coat
- Period after ripening
- Germination inhibitors
- Immaturity of the seed embryo
- Impermeability of seed coat to water
- Impermeability of seed coat to oxygen
- Mechanically resistant seed coat
- Presence of high concentrate solutes
Importance of Seed Dormancy
- It follows the storage of seeds for later use by animals and man.
- It helps in the dispersal of the seeds through the unfavorable environment.
- Dormancy induced by the inhibitors present in the seed coats is highly useful to desert plants.
- Allows the seeds to continue to be in suspended animation without any harm during cold or high summer temperatures and even under drought conditions.
- Dormancy helps seeds to remain alive in the soil for several years and provides a continuous source of new plants, even when all the mature plants of the area have died down due to natural disasters.
Types of Seed Dormancy
- Innate dormancy: It is the condition of seeds that is incapable of germination even if conditions suitable for seedling growth are supplied. This inability to germinate may be due in certain species to the embryo being immature at the time of dispersal.
- Enforced dormancy: It is the condition of seeds that is incapable of germination due to an environmental restraint which includes, an adequate amount of moisture, oxygen, light, and a suitable temperature.
- Induced dormancy: It occurs when the seed has imbibed water but has been placed under extremely unfavorable conditions for germination. Finally, the seed fails to germinate even under more favorable conditions.