 There is a plant which has produced this beautiful flower. Now cold weather sets in, there is even a little bit of frost. What do you think will happen to the flower? It will wither, right? Flowers can stand such cold weather conditions. Now there are different ways in which plants prevent such things from happening. And one of the ways is called vernalization. So what is vernalization? Vernalization, a plant does not flower until it goes through something. Prolonged cold exposure. When a plant goes through a prolonged cold exposure, what does that mean? It means it is going through winter. Only after a plant has gone through winter does it produce flowers. That means it has passed the winter, the harsh conditions of winter and finally it has reached spring. When it is safe to produce flowers, the flowers won't wither. That is the importance of vernalization to make sure nothing untoward happens to the plants when they are flowering. This phenomenon often happens in plants which have winter varieties like wheat. Wheat has two varieties, the spring variety and the winter variety. So let's see what these different varieties are. Spring variety, it is sown in spring and it flowers and sets seed. That is produces seed in summer or autumn. Now let's come to the winter variety. What does the winter variety do? It is sown in autumn and then winter comes and of course you know what will happen if it tries to flower in winter. So instead it undergoes vernalization and then it flowers in the spring. I have a question for you, what if the winter variety is sown in spring? What will happen then? So take a minute to think about it. So if the winter variety is sown in spring, will it flower in summer or in autumn? Well it can't do that because it is built in a way that it has to undergo vernalization. It has to go through the cold temperatures of winter before it can start flowering. So will it flower? No, it will not flower if it is sown in spring. It has to go through winter of that year and only after that the next year can it flower. Another type of plants which undergo vernalization are the biennials. Do you know what biennials are? These are plants which live for two years. For example there is the carrot plant which is a biennial. So let's see what happens in those two years. So in the first year what the plant does is it undergoes vegetative growth. Only vegetative growth that means the non reproductive parts of the plant grow. Flowers do not develop and then in the winter vernalization happens. Now can you tell me what will happen in year two? In year one winter they underwent vernalization, right? So naturally it follows that in year two they will flower and they will produce fruits and seeds. Now can you tell me what will happen if in year one let's say the baby plant or the young plant flowers. Let's say the vernalization phenomenon was not there, right? The plant was able to flower in year one itself but keep in mind that the plant is very young. What do you think will happen? So in a young plant it's not big enough, right? So not enough leaves. So very few leaves are there, right? And fewer leaves means what? What is the most important thing that happens in a leaf or a plant? Photosynthesis, right? So very little photosynthesis happens and that is not sufficient to provide enough nutrition for the flowers that may develop. Hence the plant cannot flower and even if it does the flowers won't survive. So this is why we have this system of year one and year two doing different things and vernalization coming in between.