US scientists unravel how plants know when to flower

US scientists have unravelled the 80-year-old puzzle of how plants know when to flower which could lead to a better understanding of how the same genes work in more complex plants. A University of Washington Assistant Professor of Biology and co-author of a paper in the May 25 issue of the Journal Science, Takato Imaizumi said, Understanding how flowering works in the simple plant used in this study - Arabidopsis - should lead to a better understanding of how the same genes work in more complex plants grown as crops such as rice, wheat and barley. Determining the proper time to flower, important if a plant is to reproduce successfully, involves a sequence of molecular events, a plant's circadian clock and sunlight, Science Daily reported. "If we can regulate the timing of flowering, we might be able to increase crop yield by accelerating or delaying this. Knowing the mechanism gives us the tools to manipulate this," Imaizumi said. Along with food crops, the work might also lead to higher yields of plants grown for biofuels. At specific times of year, flowering plants produce a protein known as Flowering Locus T in their leaves that induces flowering. Once this protein is made, it travels from the leaves to the shoot apex, a part of the plant where cells are undifferentiated, meaning they can either become leaves or flowers. At the shoot apex, this protein starts the molecular changes that send cells on the path to becoming flowers. Changes in day length tell many organisms that the seasons are changing. It has long been known that plants use an internal time-keeping mechanism known as the circadian clock to measure changes in day length. Circadian clocks synchronize biological processes during 24-hour periods in people, animals, insects, plants and other organisms. Imaizumi and the paper's co-authors investigated what's called the FKF1 protein, which they suspected was a key player in the mechanism by which plants recognize seasonal change and know when to flower. FKF1 protein is a photoreceptor, meaning it is activated by sunlight.