Bud Dormancy - Plant Growth Substances
The most important factor inducing dormancy appears to be photoperiod. Short days induce dormancy in many woody plants. The photoperiod is perceived by the leaves, but the apex or buds are the main initial responding parts of the plant. Cold itself does not appear to be necessary in the induction of dormancy. Infact, cold appears to be the most important prerequisite for breaking dormancy. Moisture, or a lack of it, appears to be important in initiating dormancy in some plants, particularly those that rely on dormancy to survive hot dry spells. A shortage of nutrients, particularly nitrogen, also appears to trigger dormancy in some plants. However, dormancy apparently does not result from a slowing down of metabolism resulting from nutrient deficiency. On the contrary, slowed metabolism is a result, not cause of dormancy.