When plants are stressed out, they generate aspirin-like chemicals. The aspirin isn't used to reduce headaches, primarily because plants don't have heads. Scientists from the National Center for Atmospheric Research detected significant quantities of methyl salicyate, a chemical form of aspirin, above a forest canopy. The capability of plants to emit the chemical had been known previously but only observed in a laboratory setting. From a press release:
(Lead researcher Thomas) 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.
The methyl salicylate also may be a mechanism whereby a stressed plant communicates to neighboring plants, warning them of the threat. Researchers in laboratories have demonstrated that a plant may build up its defenses if it is linked in some way to another plant that is emitting the chemical. Now that the NCAR team has demonstrated that methyl salicylate can build up in the atmosphere above a stressed forest, scientists are speculating that plants may use the chemical to activate an ecosystem-wide immune response…
The discovery raises the possibility that farmers, forest managers, and others may eventually be able to start monitoring plants for early signs of a disease, an insect infestation, or other types of stress. At present, they often do not know if an ecosystem is unhealthy until there are visible indicators, such as dead leaves.
"A chemical signal is a very sensitive way to detect plant stress, and it can be an order of magnitude more effective than using visual inspections," Karl says.
"Plants in Forest Emit Aspirin Chemical to Deal with Stress" (UCAR)
