Careless Whispers: Scientists discover that plants can 'talk' to each other using smells

A team of Japanese scientists has achieved a remarkable breakthrough by capturing real-time footage that showcases plants communicating with each other. The discovery, reported by Science Alert, reveals that plants release a fine mist of airborne compounds, similar to smells, to warn nearby plants of potential dangers.

The video, recorded by molecular biologist Masatsugu Toyota and his team from Saitama University, demonstrates how plants both receive and respond to these aerial alarms. The findings were published in the journal Nature Communications.

The research team, including PhD student Yuri Aratani and postdoctoral researcher Takuya Uemura, observed how undamaged plants responded to volatile organic compounds (VOCs) released by neighbouring plants under threat, such as those damaged by insects.

"Plants perceive VOCs released by mechanically or herbivore-damaged neighbouring plants and induce various defence responses. Such interplant communication protects plants from environmental threats," explained the authors in the study.

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To capture this communication, scientists employed an air pump connected to containers of leaves and caterpillars. The experiment involved allowing caterpillars to feed on leaves from tomato plants and Arabidopsis thaliana, a common mustard family weed. The responses of a second, intact Arabidopsis plant to the danger cues were then recorded.

A biosensor emitting a green glow was added to detect calcium ions, a signalling mechanism also used by human cells for communication. The video shows undamaged plants receiving messages from their injured neighbours and responding with bursts of calcium signalling that spread across their leaves.

"We have finally unveiled the intricate story of when, where, and how plants respond to airborne 'warning messages' from their threatened neighbours," remarked Toyota.

The analysis of airborne compounds revealed that two specific compounds, Z-3-HAL and E-2-HAL, induced calcium signals in Arabidopsis.

"This ethereal communication network, hidden from our view, plays a pivotal role in safeguarding neighbouring plants from imminent threats in a timely manner," added the researcher.

In a similar approach, the team measured calcium signals released by Mimosa pudica (touch-me-not) plants, known for their quick leaf movements in response to touch, as a defensive mechanism against predators. The groundbreaking research sheds light on the intricate and previously unseen ways in which plants communicate and protect each other.

(With inputs from agencies)