In other words, cold-treated plants will grow vegetatively for quite awhile before flowering. This suggests that the induced state must be permanent, or at the least be relatively stable, in many species. A hormone doesn't seem to be absolutely required since the meristem is the source of the receptor and it could pass the permanent change on to future cells. A chemical signal may be involved - the transmission of a signal through grafts has been noted with some. This hormone has been termed vernalin, but not yet isolated.
Plants can be de-vernalized if the cold treatment is followed by a heat.
Rye can also be devernalized by drying and anaerobic conditions. GA can substitute for cold in some cold-requiring species.