Plants have been found to protect themselves from freezing by activating the CBF (C-repeat binding factor) cold response pathway. This allows plants to survive when exposed to cold, nonfreezing temperatures, up to below-freezing temperatures. A recent study by the same group who discovered the CBF pathway led by Michael Thomashow, a distinguished professor of molecular genetics at Michigan State University - East Lansing, showed that the plant's defense mechanisms are also triggered by shortening daylight.

The paper published in the Proceedings of the National Academy of Sciences, shows that shortening daylight triggers trees' defenses against freezing as well as in crops and annual plants. This response is turned off however during warm growing season. This research could provide researchers information in identifying the genes involved in the process which can be used in increasing crop productivity.

The original news can be seen at http://news.msu.edu/story/plants-unpack-winter-coats-when-days-get-shorter/.