Stressed plants produce aspirin-like chemical

Tuesday, September 23, 2008 

Methyl salicylate molecule

Researchers at the National Center for Atmospheric Research have found that stressed plants produce an aspirin-like chemical, methyl salicylate. Methyl salicylate is also known as oil of wintergreen. This semi-volatile plant hormone was detected in the air above the plants in the experiments conducted in a walnut grove near Davis, California. According to the scientists the chemical may be a sort of immune response that help protect the plants.

Acetylsalicylic acid, commonly called aspirin, had originally come from the bark of Willow trees. It had never been observed to be emitted as a gas. The researchers observed spikes in methyl salicylate after nighttime temperatures dipped low, which suggested the plants were reacting to cold stress. The peaks were higher during a dry period, pointing to combined stress of cold nighttime temperatures and mild drought.

	These findings show tangible proof that plant-to-plant communication occurs on the ecosystem level.
—Alex Guenther, NCAR scientist

Laboratory observations have shown that numerous plants produce methyl salicylate, but this is the first time the phenomenon has been observed in nature. Previous studies have shown that plants being eaten by animals produce chemicals that can be sensed by other plants. A study conducted in 1997 found that methyl salicylate is produced by tobacco plants inoculated with tobacco mosaic virus. Emitting methyl salicylate may be a means for the plants to warn other plants about a threat.

The finding may help to more readily identify plants under stress by monitoring for the airborne distress signal.

Sources

• Jessica Marshall. "Plants Make Aspirin When Under the Weather" — Discovery News, September 19, 2008
• "Stressed plants release aspirin-like chemical" — Stuff.co.nz, September 20, 2008
• Randolph E. Schmid. "Aspirin: Some plants like it, too" — Fosters.com, September 21, 2008

External links

• Vladimir Shulaev, Paul Silverman and Ilya Raskin. "Airborne signalling by methyl salicylate in plant pathogen resistance" — Nature, 1997
• Karl, T., Guenther, A., Turnipseed, A., Patton, E. G., and Jardine, K.. "Chemical sensing of plant stress at the ecosystem scale" — Biogeosciences, 2008