Vernalisation is the phenomenon in which the flowering in plants is dependent on exposure to low temperatures. Vernalisation promotes flowering and enables the plant to have enough time to reach maturity. Stratification is a process which is used to break seed dormancy by providing it with the desirable conditions needed for the growth and scarification means braking of the tough exterior of the seed or weakening it to allow germination. Photoperiodism is the response of plants to the periods of day and night.