How fare, oh blossom

Vivid blossoms signal spring has arrived, but how do plants know when it’s time to flower?

Scientists have known for 80 years that plants have internal clocks that enable them to adjust leaves to maximize capture of sunlight and minimize loss of water, but they haven’t understood how it worked.

Now, researchers in Germany say they have isolated genes and proteins that are the biochemical equivalent of gears in a clock. A group of researchers at the Max Planck Institute for Plant Breeding Research in Cologne describe a molecular circuit around the protein, CONSTANS, that induces flowering.

The protein accumulates in the nuclei of cells of plants exposed to long days of spring, but it rapidly degrades during short days. It codes messages transferred to other cells to begin flowering, the scientists report.

The findings, appearing in the Feb. 13 issue of Science, could help improve crop yields because many plants, including rice, have the protein.

-- Gary Polakovic