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Thursday, March 14, 2024

How Plants Communicate When in Danger by Nancy Shepard

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://www.esalq.usp.br/lepse/imgs/conteudo_thumb/Rick-Karban-has-researched-plant-communication-in-sagebrush.pdf

https://www.advancedsciencenews.com/how-plants-signal-danger-and-fortify-neighbors-against-hungry-insects/

https://phys.org/news/2023-10-real-time-visualization-plant-plant-communications-airborne.html

https://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=18427