It was found by Lysenko (1928), a Russian worker that the cold requiring yearly and biennial plants can be made to blossom in one developing season by giving low-temperature treatment to youthful plants or dampened seeds.
He called the impact of this chilling treatment as vernalization. Vernalization is, hence, a cycle of shortening of the adolescent or vegetative stage and rushing blossoming by past cool treatment.
Some plants expect the presentation to a low temperature, 0 to 10°C, for a couple of days to half a month for blooming. Such acceptance of blooming by a low temperature is called vernalization
SITE FOR VERNALIZATION
The boost of vernalization is seen simply by the meristematic cells (active apical meristem).
e.g.- shoot tip, incipient organism tips, root summit, creating leaves, and so on
Necessities OF VERNALIZATION
(i) Low Temperature: Low temperature needed for vernalization is typically 0°—5°.
(ii) Period of Low-Temperature Treatment: It fluctuates from a couple of hours to a couple of days.
(iii) Actively Dividing Cells:
(v) Aerobic Respiration
(vi) Proper Nourishment.
MECHANISM OF VERNALIZATION
The improvement got by the effectively partitioning cells of shoot or undeveloped organism tip goes to all pieces of the plant and set it up to bloom.
The Stimulus has been named as vernalin.
It can be passed starting with one plant then onto the next through joining in the event of Henbane however not in others.
Two hypotheses. • 1. Phasic development theory • 2. Hormonal theories.
Phasic development theory
• Proposed by Lysenko in 1934
. • According to this hypothesis there is a progression of stages in the improvement of a plant.
• Each stage is animated by an ecological factor, for example, temperature, light,etc.
• Commencement of one stage will occur simply after the finishing of the procedure stage
. • There are two stages • 1.Thermophase • 2.Photophase
• Thermophase relies upon temperature.vernalization quickens thermophase.
• Thermophase ought to be trailed by photophase which requires light.
• Melcher (1939)
• He suggested that chilling treatment instigates the development of another flower hormone called vernalin.
• This hormone is sent to different pieces of the plant.
• He graphted a vernalized plant with an unvernalized plant.
• The unvernalized plant likewise starts blossoming.
• The hormone,vrnalin diffuses from the vernalized plant to the unvernalized plant and prompts blossoming.
The beneficial outcome of the low-temperature treatment on the vernalization of the plants can be checked by resulting high-temperature treatment. This is called as devernalization.
The level of devernalization diminishes if the span of the cool treatment has been longer.
However, the devernalized the plant can again be vernalized by resulting low temperature treatment.
Significance OF VERNALIZATION
Induces early blooming consequently shortening the vegetative time of the plants (creation of more than one yield in a year).
The winter assortment of harvests can be changed over to spring assortment (Protection from freezing injury).
It helps in expanding the yield of the plants.
It encourages in initiating protection from various sicknesses.
Tropical plants (requiring long summer) can be filled in calm regions (short summer).