Some plants, especially biennials and perennials, are stimulated to flower by exposing them to low temperatures. This is called vernalisation. Vernalization may be an absolute requirement (as in henbane), or may just hasten flowering (as in winter cereals). The length of chilling varies from four days to three months, temperature around 4 degree Celsius being the most effective. Vernalin is the hormone which has been suggested to be involved in this process of vernalisation. It has also been found that gibberellins level increase during vernalisation and it can also be used to introduce vernalisation in unvernalised plants.
Vernalization is a stage in the development of many plants, most notably bulbs, fruit trees, and nut trees. This stage involves exposure to cold temperatures for a set period of time, followed by a period of increased photosensitivity which allows the plant to start producing flowers. There are a number of reasons why vernalization is important to plants, and it is also useful to be aware of when forcing plants to bloom indoors or to bloom earlier than they usually do....!!@@!! :-) :-)
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