 |
| Graphic: Phys Org |
I’ve always loved the smell of a freshly mowed lawn. Little did I know that this smell is produced by the blades of grass signaling distress from being injured. Research has shown that plants emit volatile organic compounds (VOCs) into the atmosphere upon mechanical damages or insect attacks. Undamaged neighboring plants sense the released VOCs as danger cues to activate defense responses against upcoming threats.
The idea of “talking” trees started to take root in the
1980s. Two ecologists placed hundreds of caterpillars and webworms on the
branches of willow and alder trees to observe how the trees would respond. They
found the attacked trees began producing chemicals that made their leaves
unappetizing and indigestible to deter insects.
Then, starting around 2018, scientists discovered that
plants can communicate with each other by the use of chemical compounds. Here
is how it works: If one of the network plants is attacked by caterpillars, the
other members of the network are warned via an internal signal to upgrade their
chemical and mechanical resistance—making their leaves hard to chew on and less
desirable. This system works to spread the information among the plants and to
ward off caterpillars.
See this for a fascinating video that shows plant leaves
reacting to a caterpillar eating neighboring leaves. https://www.washingtonpost.com/climate-environment/2023/10/21/plants-talk-warning-danger/
 |
(Masatsugu Toyota/Toyota et al, Science 2018) |
“This is an early warning system, very much like in military defense, but then more effective: each member of the network can receive the external signal of impending herbivore danger and transmit it to the other members of the network,” said researcher Josef Stuefer from the Radboud University in the Netherlands. The attacked leaf is lost. However, the remaining leaves are protected against predators.
This discovery that injured plants emit certain chemical
compounds, which can infiltrate a healthy plant’s inner tissues and activate
defenses from within its cells, could be used soon to protect valuable crops in
agriculture. A better understanding of this mechanism could allow scientists
and farmers to help fortify plants against insect attacks or drought long
before they happen.
Sources:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3405699/
https://www.washingtonpost.com/climate-environment/2023/10/21/plants-talk-warning-danger/
https://www.livescience.com/1909-plants-communicate-warn-danger.html
https://phys.org/news/2023-10-real-time-visualization-plant-plant-communications-airborne.html
https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=18427