We are all familiar with the fact that different plants flower at different times of the year. Daffodils in spring, roses in summer and other plants in fall. It is absolutely vital for the plant survival to flower at exactly the right time to secure that it can pollinate, or be pollinated, by other plants of the same species. How then does the plant know when to flower?
Intense Florigen hunt
Already in the 30-ies scientists found out that plants can tell whether they are growing in spring, summer or fall by measuring the length of the day. One could also show that plants use their leaves to sense the length of the day. By grafting leaves from plants that had been induced to flower on non-induced plants one could show that the induced leaves produce a substance that is transported to the shoot tips where it induces the formation of flowers. In the 30-ies a Russian scientist called this mysterious substance "Florigen". During the following 70 years scientists have been involved in an intense hunt trying to find out the true nature of "Florigen" which has been described as something of a "Holy Grail" for plant physiology.
The reason is that the nature of "Florigen" is central for our understanding of how plant flowering is controlled. All attempts to identify a single substance carrying the properties of "Florigen" have failed, until now.
Contact: Gunilla Ramberg
Swedish Research Council