Vernalization

Vernalization is the induction of a plant's flowering process by exposure to a prolonged period of cold, typically the cold of winter or an artificial equivalent, usually between 1 and 7 degrees Celsius. After vernalization a plant becomes able to flower, though it may still need further seasonal cues or additional growth before actually doing so, and the requirement helps ensure reproductive development and seed production happen in spring rather than autumn. Many perennial plants, such as fruit trees, need a period of cold to enter dormancy before later re-emerging from it to flower, and many winter annual and biennial plants, including some ecotypes of Arabidopsis thaliana and winter cereals such as wheat, must pass through a prolonged cold period before they will flower at all.