Seed Dormancy – Definition & Detailed Explanation – Phenology Glossary

What is seed dormancy?

Seed dormancy is a phenomenon in which a seed fails to germinate even under optimal environmental conditions. This dormancy allows seeds to remain viable for extended periods, waiting for the right conditions to germinate. It is a crucial adaptation that allows plants to survive in harsh environments and ensures the timing of germination is favorable for the plant’s growth and reproduction.

How does seed dormancy occur?

Seed dormancy can occur due to various factors, including physical, physiological, and environmental factors. Physical dormancy, also known as seed coat dormancy, occurs when the seed coat is impermeable to water and gases, preventing germination. Physiological dormancy, on the other hand, is caused by internal factors within the seed that inhibit germination. Environmental factors such as temperature, light, and moisture levels can also play a role in inducing seed dormancy.

What are the types of seed dormancy?

There are several types of seed dormancy, including:

1. Physical dormancy: This type of dormancy is caused by the impermeability of the seed coat, which prevents water and gases from entering the seed.
2. Physiological dormancy: In this type of dormancy, internal factors within the seed, such as hormones and enzymes, inhibit germination.
3. Morphological dormancy: This type of dormancy is characterized by the need for specific environmental cues, such as cold stratification, to break dormancy.
4. Combined dormancy: Some seeds may exhibit a combination of physical and physiological dormancy, making them even more challenging to germinate.

What factors influence seed dormancy?

Several factors can influence seed dormancy, including:

1. Temperature: Some seeds require specific temperature fluctuations, such as cold stratification, to break dormancy.
2. Light: Light can play a role in breaking dormancy for some seeds, while others may require darkness to germinate.
3. Moisture: The availability of water can influence seed dormancy, with some seeds requiring specific moisture levels to germinate.
4. Hormones: Plant hormones, such as abscisic acid, can regulate seed dormancy by inhibiting germination until favorable conditions are present.

How can seed dormancy be broken?

Seed dormancy can be broken through various methods, depending on the type of dormancy present. Some common methods include:

1. Scarification: Physical dormancy can be broken by scarifying the seed coat, either mechanically or chemically, to allow water and gases to enter the seed.
2. Stratification: Cold stratification involves exposing seeds to cold, moist conditions for a specific period to break dormancy.
3. Light exposure: Some seeds require exposure to light to break dormancy, while others may require darkness.
4. Hormone treatments: Applying plant hormones, such as gibberellins, can help break physiological dormancy and promote germination.

What is the significance of seed dormancy in plant ecology?

Seed dormancy plays a crucial role in plant ecology by allowing plants to survive in challenging environments and ensuring the timing of germination is optimal for growth and reproduction. Dormancy also helps plants avoid germinating during unfavorable conditions, such as drought or extreme temperatures, which could be detrimental to seedling survival. Additionally, seed dormancy contributes to the diversity of plant species by allowing seeds to remain viable for extended periods, waiting for the right conditions to germinate. Overall, seed dormancy is a vital adaptation that enhances the survival and reproductive success of plants in a wide range of habitats.