Vernalisierung

Vernalisierung, also known as vernalization, is a physiological process in plants where a period of cold treatment is required to induce flowering. This phenomenon is a crucial adaptation for many plant species that grow in temperate climates, ensuring that they flower and set seed during the favorable conditions of spring and summer, rather than during the harsh winter months.

Plants that undergo vernalization typically have a life cycle that includes a dormant period during winter. The cold treatment, often experienced as prolonged exposure to temperatures near freezing, triggers a cascade of molecular events within the plant. This leads to the formation of floral meristems, the structures that will eventually develop into flowers. Without this cold stimulus, the plant may remain vegetative, producing leaves and stems but no flowers, even if other environmental conditions, such as sufficient light and nutrients, are met.

The duration and temperature range required for vernalization vary significantly among different plant species. Some plants, like winter cereals (e.g., winter wheat and winter rye), require extended exposure to cold to germinate and develop properly. Others, such as certain biennials (e.g., parsley and foxglove), need vernalization to transition from their vegetative growth phase in the first year to reproductive flowering in the second year. The sensitivity to cold can also be influenced by other factors, including plant age and the presence of specific hormones like gibberellins. Vernalization is a key concept in plant physiology and has significant implications for agriculture, allowing for the cultivation of crop varieties in different climates and influencing planting times.