Plants in Forest Emit Aspirin Chemical to Deal with Stress
In a new study released today, it has been found that plants respond by producing an amount of a chemical form of aspirin.
The study was conducted by scientists at the National Center for Atmospheric Research (NCAR), which teaches us a lot about plants' impacts on air quality and could give farmers an early warning sign when crops are failing.
"Unlike humans, who are advised to take aspirin as a fever suppressant, plants have the ability to produce their own mix of aspirin-like chemicals, triggering the formation of proteins that boost their biochemical defenses and reduce injury," says NCAR scientist Thomas Karl, who led the study. "Our measurements show that significant amounts of the chemical can be detected in the atmosphere as plants respond to drought, unseasonable temperatures, or other stresses."
For years, scientists have known that plants in a laboratory may produce methyl salicylate, which is a chemical form of acetylsalicylic acid, or aspirin. But researchers had never before detected methyl salicylate in an ecosystem or verified that plants emit the chemical in significant quantities into the atmosphere.
The team of scientists reported its findings last week in Biogeosciences. The research was funded by the National Science Foundation, NCAR's sponsor.
An unexpected finding
Researchers had not previously thought to look for methyl salicylate in a forest, and the NCAR team found the chemical by accident. They set up specialized instruments last year in a walnut grove near Davis, California, to monitor plant emissions of certain volatile organic compounds (VOCs). These hydrocarbon compounds are important because they can combine with industrial emissions to affect pollution, and they can also influence local climate.
When the NCAR scientists reviewed their measurements, they found to their surprise that the emissions of VOCs included methyl salicylate. The levels of methyl salicylate emissions increased dramatically when the plants, which were already stressed by a local drought, experienced unseasonably cool nighttime temperatures followed by large daytime temperature increases. Instruments mounted on towers about 100 feet above the ground measured up to 0.025 milligrams of methyl salicylate rising from each square foot of forest per hour.
Karl and his colleagues speculate that the methyl salicylate has two functions. One of these is to stimulate plants to begin a process known as systemic acquired resistance, which is analogous to an immune response in an animal. This helps a plant to both resist and recover from disease.
This shows that plant to plant communication exists on the ecosystem level. They can effictively communicate through the atmosphere.
This could mean that farmers could start monitoring plants for early signs of disease, an insect infection or other types of stress that affect plants, and could save thousands of species as usually the only way to tell a plant is infected is when the leaves are dead or decayed and by then that is too late usually to save the plant.