Importance of photoperiodism:
If all the plants were short-day plant or all long - day plant, then we would get only one crop in a year. There would be problem in preservation of crops, again in a certain time in the year there will be scarcity of various fruits. As there are short day plants, long-day plants and day-neutral plants in nature, thus we get some one or other crops, vegetables or fruits throughout the year.
Like light, temperature and cold also have effects on plant growth and flowering. It was seen, that in many germinating seeds when treated with cold cause early flowering. Application of cold treatment to germinating seeds to effect early flowering is called vernalization.
In 1920 AD Russian scientist T. D Lysenko invented this method of acceleration the ability to flower by cold treatment and named as Jarovization. Later the term Jarovization was renamed in Latin as vernalization.
Vernalization is induced on germinating seeds or young seedlings. They are kept in low temperature (usually 13¡ - 15¡C) for some days thus cold treatment completed. The apical meristamatic cells of the plumule or seedling receive stimulation of vernalization.
Importance of Vernalization: In Russia Biannic wheat is converted to annualone by vernalization treatment. In our country large amount of paddy is being destroyed by flood. If the flowering time of paddy be accelerated by 5 - 10 minutes then it will be possible to protect paddy of Crores of Taka.