June 24, 2013
Plants Do The Math In Order To Survive Without Sunlight
Brett Smith for redOrbit.com - Your Universe Online
At night, plants must utilize nutrient reserves efficiently until dawn and new research from the John Innes Centre in England has found that some plants use basic math to survive without sunlight for photosynthesis.The British scientists said they were surprised to discover that Arabidopsis uses two different kinds of internal molecules to determine a rate for breaking down starch reserves.
"This is the first concrete example in biology of such a sophisticated arithmetic calculation," said Professor Martin Howard, a mathematical modeler at the John Innes Centre.
The consumption of starch, which is made from carbon dioxide and sunlight during the day, provides energy for vital plant processes during the night and is fundamental to the plant’s survival.
According to the team’s report in e-Life journal, the starch consumption process is mediated by the amounts of two kinds of molecules: "S" for starch and "T" for time. If the S molecules are responsible for breaking down starch and the T molecules block the process, then the rate of starch consumption equals the number of S molecules divided by the number of T molecules, the UK researcher said.
"The calculations are precise so that plants prevent starvation but also make the most efficient use of their food,” Smith said. “If the starch store is used too fast, plants will starve and stop growing during the night. If the store is used too slowly, some of it will be wasted."
While previous studies had shown that plants use starch reserves at night, the John Innes researchers began looking into the mechanism behind the process by discovering that Arabidopsis plants used about 95 percent of their stock each night.
When study researchers artificially changed the duration of light conditions, the plants either slowed or increased their rate of starch consumption appropriately. This adaptation suggested to the researchers that the plants had some type of internal clock-based mechanism (T), Smith explained. When the plants were exposed to less light – generating less starch – they consumed it more slowly, indicating that the calculation was also based on internal starch reserves (S).
Even when scientists attempted to “trick” the plants by inserting periods of light during nighttime periods, the plants adjusted, showing some type of calculated compensation.
Observers pointed out that the study’s findings do not represent plant intelligence – only a biological system set up to perform a simple calculation
The researchers said their equation helps to explain a metabolic process in Arabidopsis and a similar calculation could also be occurring in other organisms where nutrients are internally stored ahead of extended periods without sustenance, and this supply runs out just as the period of fasting ends.
For example, some Arctic birds travel around 2,700 miles to breed and arrive at their destination with fat reserves so low that they could only survive another 14 hours, the study researchers said in their report.