Dormancy in plants is a temporary period of inactivity in growth, a natural survival strategy. It's akin to a plant taking a "nap" to conserve energy and survive unfavorable environmental conditions. This rest period allows the plant to resume growth when conditions become more favorable. According to one reference, "A period of dormancy during which growth temporarily ceases is a feature of the annual growth cycle of many plants."
Why Do Plants Go Dormant?
Plants enter dormancy to survive conditions that are not conducive to growth, such as:
- Cold temperatures: Many plants in temperate climates become dormant during winter.
- Drought: In arid regions, dormancy helps plants survive dry seasons.
- Short days: Some plants respond to decreasing day length by entering dormancy.
Types of Dormancy
Dormancy can be triggered by different factors and manifest in different ways.
- Environmentally-Imposed Dormancy: As the reference states, growth inactivity "can be imposed directly by the environment (by low-winter temperatures, for example)." This means that unfavorable external conditions directly cause the plant to become dormant.
- Apical Dominance: The reference also mentions that "for the lateral buds, may be a consequence of apical dominance by the terminal bud." This type of dormancy is controlled by hormones produced in the terminal bud, which suppress the growth of lateral buds.
Examples of Dormancy
Here are a few examples illustrating plant dormancy:
| Plant | Reason for Dormancy | Manifestation |
|---|---|---|
| Deciduous Trees | Cold Winter | Shedding leaves, ceasing growth, reduced metabolism |
| Bulbs (Tulips) | Cold Winter | Underground storage organ remains inactive |
| Desert Plants | Drought | Shedding leaves, reduced metabolism |
Breaking Dormancy
Dormancy is not a permanent state. Plants need specific cues to break dormancy and resume growth. Common triggers include:
- Rising temperatures: Warmer temperatures in spring signal the end of winter dormancy.
- Increased day length: Longer days indicate the arrival of spring.
- Adequate moisture: Sufficient water availability breaks dormancy in drought-adapted plants.
- Chilling Requirement: Some plants require a certain period of cold temperatures (vernalization) to break dormancy and flower properly.
- Scarification: Some seeds require the seed coat to be broken or weakened (scarified) to allow germination, effectively ending dormancy.
