Vernalization is a phenomenon that is used to increase the yield of earlier crops by allowing them to grow longer. Most of the time, they are grown in areas where they would not naturally occur. The process of vernalization aids in the acceleration of plant breeding.
For example, wheat plants that produce two types, winter and spring, are a good example. Vernalization occurs in vegetables such as beet, cabbage, turnips and onions.
During the autumn planting season, the winter variety is planted. They are given enough time to germinate and emerge as small seedlings in the winter, after which they continue to grow in the spring and are harvested in the mid-summer months.
This is the process of vernalization.
The term “vernalization” is derived from the Latin word “vernus,” which literally translates as “of spring.” It refers to the process of creating something that is “spring-like.” It is the induction of the flowering process in a plant as a result of prolonged exposure to cold winter temperatures or other similar situations. Plants develop the ability to blossom once this process has been completed in their development. However, it is possible that they will require a further few seasonal weeks of growth before they flower.
Flowering is facilitated throughout the process of vernalization by administering a cold treatment to a fully hydrated seed or to a developing plant. As a result of the process of vernalization, the plant’s vegetative phase is restricted, which results in the plant blooming earlier than normal. The absence of cold treatment causes the blossoming of plants that require vernalization to be delayed or to remain in vegetative state.
Vernalization occurs through a variety of mechanisms.
Through the process of vernalization, the process of flowering is expedited as a result of a postponed time of low temperatures, such as those that are experienced during the winter. There are two primary ideas that can be used to describe the mechanism of vernalization —
- The notion of phasic development
- The Theory of Phasic Development
According to this idea, there is a systematic organisation of stages in the plant’s development. Various environmental factors like light, temperature, and other factors influence each stage of the process. There are two major stages in this process — the initial stage and the final step.
Thermostage
It is dependent on temperature, with vernalization speeding up the thermostat age process. Thermalization is the vegetative phase, during which low heat, aeration, and sufficient moisture are required.
Photostage
The photostage needs the use of high temperatures. Vernalin has a role in the production of florigen in this situation.
Theories based on hormones
According to this concept, the freezing treatment stimulates the production of a floral hormone known as vernalin. A hormone of this type is sent to numerous regions of the plant. The vernalin hormone is released by the vernalized plants and diffuses to the vernalized plants, causing them to bloom.
Vernalization in Plants – The location of vernalization in plants
The apical meristems, which are metabolically active, are the areas where the plant perceives temperature changes, which allows it to begin flowering. Younger leaves are more sensitive to the process of vernalization than older leaves. Low temperature stimulation is applied to the shoot apex of mature stems or the embryo of seeds. Because of this, the stimulation from this process is only detected by meristematic cells, such as the tips of shoots, the apex of roots, the growing leaves, the embryonic tips, and so on.
Examples of vernalization
Some food plants are available in two varieties: a spring version and a winter variation. The spring type is normally planted in the spring. As a result, blooms begin to generate grains near the conclusion of the growing season. While the winter variety is planted in the fall and germinates in the winter, the spring variety is planted in the spring and harvested in the summer following its planting. Biennial plants require two years to flower because they grow their stems, leaves, and roots in the first year and go into hibernation during the colder months of the year. It is necessary to have a time of cold, or vernalization, in order for the flowering process to begin in the following months. Biennial plants flower and produce fruit gradually over time, and then die in the summer or spring following their flowering season. Cabbage, carrots, and sugar beets are examples of such vegetables.
Garlic is primarily planted during the winter months since it requires a cold environment to thrive (vernalization). In the case that the temperature does not drop to a specific level for a specified period of time, garlic does not form bulbs, and winter wheat does not blossom and frame grain for the following growing season.
Devernalization
It is possible to revert the process of vernalization as a result of being exposed to greater temperatures, which is known as devernalization. The treatment of vernalized buds or seeds with a wide range of temperatures has an effect on this process. Lang and colleagues proved in 1957 that the application of gibberellin coils can substitute for the application of cold treatment in the case of some biennial plants.
Factors that influence vernalization
There are several elements that influence the process of vernalization, including:
- The plants’ age is indicated by the asterisk (*).
- Vernalization took place at this location.
- Provision of an appropriate low temperature environment
- Oxygen
- the time period during which you were exposed
- Water
Conclusion
Low temperature is an important component in a plant’s early blossoming. “Vernalisation” is defined by Chouard as “the acceleration of the ability to induce flowering by chilling treatment (10–100C).” Vernalisation is a cold treatment that can be replaced by spraying gibberellins. Plants that are biennials can be coaxed to flower in a single year by using a cold treatment. Flowers can blossom sooner than usual or in warm climates that lack the requisite seasonal cold by satisfying the cold requirement of many temperate-zone plants.
Flowering is induced by vernalisation, which occurs in actively dividing cells and requires oxygen, nutrients, and a low temperature for a period of time. Temperature has a quantitative and qualitative impact on flowering.