Follow section front redirects in Spectrum

Enable NLP source in PCS for load testing

Switch off the News Alerts Survey Widget when we have enough responses

Poll to determine if new LUF updates are available

Allows the winning A/B test variant to be turned on without Spectrum deployment

Show infinite scrolling sections in Assembler MultiView

Show option for NLP article summaries in Action Bar

A general feature flag for Recipe Features that aren't yet released

Feature flag for media team features that aren't yet released

Use new Orca video player for preroll plugin in Spectrum

Show the snow tracker (instead of the heat tracker) on Spectrum

Soldiers reunite with their pets from overseas: ‘It meant everything to me’

Chiropractor works on giraffe, is nuzzled: ‘Giraffes are just giant dogs?’

An SUV was in flames on the highway. Strangers saved the driver.  

Trump and allies say Biden pays rent for ‘illegals’ in Michigan. Not true.

Eighty percent of Ukraine-Israel bill will be spent in U.S. or by U.S. military

Facts in the Trump courtroom v. ‘facts’ in the court of public opinion

As U.S. rushes to send military aid, Ukrainians applaud lobbying effort

An assassination plot on American soil reveals a darker side of Modi’s India

Scotland leader Humza Yousaf resigns in latest setback for independence 

The Rick Steves guide to life

The sad, stale state of in-flight vegetarian meals

How to train for a marathon on vacation

A TikTok ban could also end short-form video as we’ve come to know it

Meta’s oversight body prepares to lay off workers

An AI blood test purports to diagnose postpartum depression

Election 2024 latest news: Trump, Biden returning to campaign trail this week

Tensions grow between Trump and Lake in Arizona race for Senate 

Middle East conflict live updates: Britain urges Hamas to accept ‘very generous’ 40-day Gaza cease-fire deal

Jayden Daniels is latest in Washington’s checkered history of first-round QBs

The Rangers swept the Capitals, and it’s time for the new core to take charge

The new face of flooding

Where seas are rising at alarming speed 

Red carpet looks from the White House correspondents’ dinner

Ask Amy: Boyfriend’s CPA dad did my taxes wrong for years

Miss Manners: I think kindergarten graduations are ‘ridiculous’

Carolyn Hax: Is checking his phone the best way to prove he isn’t lying anymore?

Is student loan debt an emergency? Take our quiz.

Humans might need to re-engineer the climate

The Fed’s fight against inflation needs to lose the dot plot

 Donald Trump Speaks During A Campaign Rally In Green Bay Wisconsin

Reporting on Earth’s changing climate and the search for solutions

See more coverage in your recommendations

Climate & environment

The Climate Coach newsletter

Climate alerts

It sounds like fiction from “The Lord of the Rings.” An enemy begins attacking a tree. The tree fends it off and sends out a warning message. Nearby trees set up their own defenses. The forest is saved.

But you don’t need a magical Ent from J.R.R. Tolkien’s world to conjure this scene. Real trees on our Earth can communicate and warn each other of danger — and a <a href="https://www.nature.com/articles/s41467-023-41589-9" target=_blank>new study</a> explains how.

Injured plants emit certain chemical compounds, which can infiltrate a healthy plant’s inner tissues and activate defenses from within its cells, the new research found. A better understanding of this mechanism could allow scientists and farmers to help fortify plants against insect attacks or drought long before they happen.

For the first time, researchers have been able to “visualize plant-to-plant communication,” said Masatsugu Toyota, senior author of the study, which was published Tuesday in Nature Communications. “We can probably hijack this system to inform the entire plant to activate different stress responses against a future threat or environmental threats, such as drought.”

Masatsugu Toyota

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. <a href="https://www.washingtonpost.com/archive/politics/1983/06/06/2-scientists-say-trees-warn-each-other-when-bugs-bite/561ab5a9-25d5-4687-9512-efe985235b00/" target=_blank>They found</a> the attacked trees began producing chemicals that made their leaves unappetizing and indigestible to deter insects.

But even more curious, the scientists discovered healthy trees of the same species, located 30 or 40 meters away and with no root connections to the damaged trees, also put up the same chemical defenses to prepare against an insect invasion. Another pair of scientists around that time <a href="https://www.science.org/doi/10.1126/science.221.4607.277" target=_blank>found similar results</a> when studying damaged sugar maple and poplar trees.

These early research teams had a budding thought: The trees sent chemical signals to one another through the air, known today as plant eavesdropping. Over the past four decades, scientists have observed this cell-to-cell communication in more than 30 plant species, including lima bean, tobacco, tomato, sage brush and flowering plants in the mustard family. But no one knew which compounds were important and how they were being sensed — until now.

“There was this kind of controversy in the field,” said André Kessler, a plant ecologist who was not involved in the research. “First, how those compounds in general are taken up [by the plant], and then how they are able to change the plant’s metabolism in response to perceiving them.”

Kristi Blokhin

Craig Hudson

Kessler said this study helped answer some of those long-standing questions.

Plants obviously don’t have ears and eyes, but past research shows they communicate with their surroundings by emitting chemicals known as volatile organic compounds, which we can smell. But just as people can speak so many words, plants can produce an array of these compounds for different purposes. Some are used to attract pollinators or as defense against predators.

However, one class of these compounds are emitted when a plant is injured: green leafy volatiles. These are emitted by, as the name suggests, pretty much every green plant with leaves, and are produced when a plant experiences physical damage. An example of this compound is the smell released from fresh-cut grass.

In the new study, Toyota and his colleagues manually crushed leaves and placed caterpillars on Arabidopsis mustard or tomato plants to trigger the emission of various green leafy volatiles. Then, they spread individual fumes to healthy plants to see if the plants would react.

To track the healthy plants’ responses, the team genetically modified the plants so calcium ions would fluoresce when activated inside individual cells. Calcium signaling is important for cellular functions in most living organisms on Earth, including humans. When an electrical signal is sent to our motor neurons, ion channels open and allow calcium to flood inside. This increase in calcium can trigger a neurotransmitter release, which results in a muscle contraction in a muscle cell.

Calcium signaling, Toyota said, plays a similar role in plants. Depending on the plant, it can trigger messages to close its leaves or digest an insect.

Masatsugu Toyota/Saitama University

After testing many green leafy volatiles, the team found only two seemed to increase calcium ions inside cells. Additionally, they found calcium signaling first increased in guard cells forming the plant’s leaf pores, or stomata — an important finding, because it shows the compounds are absorbed into the plant’s inner tissues.

“They cannot just seep through the surface of the plant easily,” said Kessler, a professor at Cornell University. “They have to go through the stomata, [which] allow the plant to actually breathe carbon dioxide in and oxygen out for photosynthesis.”

The calcium signaling, Toyota said, is like a switch to turn on the defense responses from the plant. After signaling increased, the team found the plant increased the production of certain gene expressions for protection. For example, Toyota said the plant may start producing certain proteins to inhibit insects from munching on them, giving the insects diarrhea.

“If the plant has lots of these genes, they are now very strong against the insect herbivory,” Toyota said.

With this new understanding, researchers say plants could be immunized against threats and stressors before they even happen — the equivalent of giving a plant a vaccine. For instance, exposing healthy plants to insect-ridden plants or the associated green leafy volatiles could boost their genetic defenses, so farmers use less pesticides, Kessler said. The revelation could also help make plants more resilient during a drought, signaling the plants to retain more water.

“If you have a plant early in its life exposed to drought, it will actually handle drought better than a plant that was not exposed to that,” Kessler said. “This is also a result of the plant’s metabolism totally changed.”

The advancement has planted many seeds for future research, Toyota said. For instance, researchers “have no idea” why only two specific green leafy volatiles could enter the stomata and trigger the calcium signaling. The next step is to identify the various receptors in the plants, which may be specific to the chemical structure of the two compounds.

In response to insect attacks, plants can also produce specific responses based on the species of the herbivore feeding on it, an impressive behavior that Kessler is further studying.

“If that plant can mount an adaptive response … this is the definition of intelligence,” Kessler said. “If you understand these kinds of things and how plants do it, it gets you onto a level that questions how we understand the world.”

This article is part of <a href="https://www.washingtonpost.com/climate-environment/hidden-planet/" target=_blank>Hidden Planet, </a>a column that explores wondrous, unexpected and offbeat science of our planet and beyond.

Wake Forest University, BS in Chemistry

Boston University, MS in Science Journalism

Kasha Patel writes the weekly Hidden Planet column, which covers scientific topics related to Earth, from our inner core to space storms aimed at our planet. She also covers weather, climate and environment news.

Kasha Patel

How plants communicate with each other when in danger

the-washington-post

Illustration by Emily Sabens/The Washington Post; iStock

The Washington Post

planttalk topper

A photo of a plant inside a "danger" symbol with a headline that reads: How plants communicate with each other when in danger

The Washington Post; iStock

Emily Sabens

Environment

Weather

Climate Solutions

Climate Lab

Green Living

Business of Climate

Climate

washpost

prism://prism.query/site-articles-only,/climate-environment&limit=20

Sign up for the Climate Coach newsletter and get advice for life on our changing planet, in your inbox every Tuesday.