From our perspective as Adenium obesum plants, dormancy is not a choice but a vital, instinctive response to environmental cues. Our primary trigger is the combination of decreasing daylight hours and lower temperatures. As the intensity and duration of sunlight diminish, our photosynthetic activity slows. Concurrently, cooler temperatures, especially at night, signal to our internal systems that a period of resource scarcity is approaching. This is not a sudden shutdown but a gradual winding down of metabolic processes. We begin to reallocate valuable resources, primarily sugars and starches, from our leaves and fine roots to our most crucial organ: our large, succulent caudex. This water-storing stem is our lifeline, designed to sustain us through the harsh season.
The most visible sign of our entry into dormancy is leaf loss. We actively initiate abscission, severing the connection at the leaf petioles. This is a strategic conservation tactic. Leaves are major sites of transpiration (water loss) and would continue to lose precious water vapor during a time when we cannot replace it through our dormant roots. By jettisoning our foliage, we dramatically reduce water loss and eliminate structures that would otherwise consume stored energy. Internally, our cellular metabolism slows to a near standstill. Growth hormones like auxins and gibberellins decrease in production, while abscisic acid, a hormone that inhibits growth and promotes stomatal closure, becomes more dominant. Our respiration rate drops significantly, allowing us to survive on the energy reserves stored within our caudex.
During true dormancy, our above-ground growth completely ceases. We enter a state of rest where our energy consumption is minimal. It is a common misconception that we require water during this time; in fact, hydrating cold, dormant roots can lead to rot, as our ability to uptake water is suspended and the cold, wet conditions create a perfect environment for fungal pathogens. Our focus is entirely on preserving the core root system. While the finer feeder roots may die back, the main structural roots remain alive, albeit in a quiescent state. The caudex may soften slightly, which is a normal adaptation as we utilize its internal water stores. This period of rest is not one of death but of profound energy conservation, allowing us to survive conditions that would otherwise be fatal.
Our emergence from dormancy is triggered by the reversal of the initial environmental cues: consistently warmer temperatures and longer daylight hours. As the soil warms, it stimulates activity in our root system. We begin to very cautiously uptake water, which rehydrates our tissues and signals the caudex to mobilize its stored energy. This energy is directed towards the production of new growth points. The first sign is often the swelling of buds, followed by the emergence of new leaves and, shortly after, flower buds. This new growth is fueled entirely by our stored reserves until the new leaves are sufficiently developed to resume photosynthesis and become the primary energy source for the next season's growth cycle.
