külmavajadusega

Külmavajadus refers to the chilling requirement of certain plants to experience a period of cold temperatures before they can initiate flowering or resume growth. This physiological process is crucial for the vernalization of many temperate climate species. Plants that exhibit külmavajadus typically have seeds or vegetative buds that remain dormant through the winter. The prolonged exposure to cold, often between 0 and 10 degrees Celsius, triggers metabolic changes within the plant.

These changes can include the activation of specific genes responsible for flowering and the breakdown of inhibitors that prevent premature development. Without sufficient cold exposure, these plants may fail to flower altogether, produce significantly fewer flowers, or exhibit delayed and weaker growth. Common examples of plants requiring külmavajadus include winter cereals like wheat and rye, many fruit trees such as apples and cherries, and ornamental plants like tulips and hyacinths.

The duration and intensity of the cold period needed can vary considerably between species and even between different cultivars of the same species. This phenomenon is a key factor for growers in regions with mild winters, as they may need to artificially induce cold conditions for their crops, for instance, by using vernalization techniques for seeds or by ensuring adequate winter chilling for fruit trees. Understanding külmavajadus is essential for successful cultivation and for breeding new plant varieties adapted to specific climates.