Development and Differentiation of a flowering plant

The developmental phases of a flowering plant involve seed germination, vegetative growth, flowering, fruiting and senescence. These phases are precisely timed and are under strict internal and external controls. You must have noticed that a seed remains dormant all winter long buried in the sand, suddenly germinates and the plant flowers in the spring. A short rainfall in desert brings life to many plants and the dormant winter buds become active in the spring.

What external or internal factors initiate germination which involves resumption of all the metabolic activities? How does a seed sense that all the environmental conditions are favourable for its germination and growth and how do buds know that the winter is over? You also know that most fruits, vegetables and flowers are seasonal. Chrysanthemums bloom in winters while Gulmohar and Amaltas bloom in the summer. Why do some plants bloom in the spring and others wait for summer, fall or winter? Many flowers open and close on a fixed schedule as if a clock is present in their cells. Now it would be interesting to find out whether it is possible to grow chrysanthemums throughout the year or make Morning glories bloom at dusk? You can ask many such questions with regard to development of a plant.