Arabidopsis thaliana: A model plant for scientific experiments
Plants have a built-in capacity to do
maths, which helps them regulate food reserves at night, research suggests.
UK scientists say they were "amazed" to find an example of such a
sophisticated arithmetic calculation in biology.
Mathematical models show that the amount of starch consumed overnight is
calculated by division in a process involving leaf chemicals, a John Innes
Centre team reports in e-Life journal.
Birds may use similar methods to preserve fat levels during migration.
The scientists studied the plant Arabidopsis, which is regarded as a
model plant for experiments.
Overnight, when the plant cannot use energy from sunlight to convert carbon
dioxide into sugars and starch, it must regulate its starch reserves to ensure
they last until dawn.
Experiments by scientists at the John Innes Centre, Norwich, show that to
adjust its starch consumption so precisely, the plant must be performing a
mathematical calculation - arithmetic division.
"They're actually doing maths in a simple, chemical way
- that's amazing, it astonished us as scientists to see that," study leader Prof
Alison Smith told BBC News.
"This is pre-GCSE maths they're doing, but they're doing maths."
The scientists used mathematical modelling to investigate how a division
calculation can be carried out inside a plant.
During the night, mechanisms inside the leaf measure the size of the starch
store. Information about time comes from an internal clock, similar to the human
body clock.
The researchers proposed that the process is mediated by the concentrations
of two kinds of molecules called "S" for starch and "T" for time.
If the S molecules stimulate starch breakdown, while the T molecules prevent
this from happening, then the rate of starch consumption is set by the ratio of
S molecules to T molecules. In other words, S divided by T.
"This is the first concrete example in biology of such a sophisticated
arithmetic calculation," said mathematical modeller Prof Martin Howard, of the
John Innes Centre.
The scientists think similar mechanisms may operate in animals such as birds
to control fat reserves during migration over long distances, or when they are
deprived of food when incubating eggs.
Commenting on the research, Dr Richard Buggs of Queen Mary, University of
London, said: "This is not evidence for plant intelligence. It simply suggests
that plants have a mechanism designed to automatically regulate how fast they
burn carbohydrates at night. Plants don't do maths voluntarily and with a
purpose in mind like we do."
