New Study Reveals How Plants Shed Off Parts

A new study conducted by researchers from the University of Missouri reports on the mechanism of abscission, the process that governs how and when plants shed their parts. The early steps of abscission involve changes in a special layer of cells, called the abscission zone, located at the base of the flower. When a flower matures, cells in this layer begin to separate from one another along the entire zone, creating a clean rift between the base of the flower and the petals. As the rift enlarges, the petals fall off.

One gene that gets a boost in its activity is called HAESA, a gene required for floral abscission to occur. Previous studies have shown that the activity of this gene increases 27-fold from the time the flower bud opens to when it drops its petals, a period of about 2 days. The research team found that plants that overexpress a certain regulator protein do not activate HAESA and do not drop their flower petals.

The results suggest that the protein found is a negative regulator of HAESA, which prevents its expression. The protein also acts as a molecular "switch" responsible for turning the process on and off and it is this "positive feedback loop" that is important in the abscission process.

For more details about this research, read the news release from University of Missouri.