Plant Mathematics

By Molly Michelson

Plants are constantly proving that there’s more to them than meets the eye. We’ve written here before about plants seeing, hearing, and feeling; now researchers have discovered that our not-so-simple green friends also use mathematics.

Publishing in the open access journal eLife, scientists describe how plants can calculate how much starch to store at night, so they can continue growing 24/7.

Plants feed themselves during the day using energy from the sun to convert carbon dioxide into sugars and starch. Once the sun has set, they must depend on a store of starch to prevent starvation.

Studying Arabidopsis plants, the researchers determined that during the night, mechanisms inside the leaf measure the size of the starch reserve and estimate the length of time until dawn. Information about time comes from an internal clock, similar to our own body clock. The size of the starch store is then divided by the length of time until dawn to set the correct rate of starch consumption, so that, by dawn, around 95% of starch is used up.

The team used mathematical modeling to investigate how such a division calculation can be carried out inside a plant. They believe that information about the size of the starch store and the time until dawn is encoded in the concentrations of two kinds of molecules (one called “S” for starch, and the other, “T” for time). If the S molecules stimulate starch consumption, while the T molecules prevent this from happening, then the rate of starch consumption is S divided by T.

“The capacity to perform arithmetic calculation is vital for plant growth and productivity,” says study co-author Alison Smith, of the John Innes Centre. “Understanding how plants continue to grow in the dark could help unlock new ways to boost crop yield.”

Just don’t expect our leafy friends to balance your checkbook for you…

Image: Roepers