Watch: Plant caught on cam ‘talking’ to neighbouring plant in groundbreaking study

Just like humans, plants also communicate with each other as soon as any danger or attack is detected in their neighbourhood. Scientists know about this phenomenon since the 1980s, having identified at least 80 species who act in their defence in crisis situations. However, it was still shrouded in mystery as to how exactly plants receive such danger signals from their neighbours.

Now, a team of Japanese scientists has not just solved this puzzle but also filmed the communication among plants in an amazing video. In a study published in Nature Communications, molecular biologists at Saitama University in Japan, Yuri Aratani and Takuya Uemura, demonstrated how these plants behave upon detecting danger.

Set up created using engineered plants

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To conduct the experiment, scientists set off caterpillars on leaves cut from tomato plants and a commonly used weed called Arabidopsis thaliana. To better analyse its impact on the neighbouring plant, the compounds were concentrated in a plastic bottle and pumped onto the recipient plant at a constant rate.

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Also, the recipient Arabidopsis plant was not an ordinary plant but was genetically engineered so that its cells contained a biosensor that fluoresced green when an influx of calcium ions was detected.

How undamaged plants responded?

In the video, undamaged plants clearly responded to messages from their injured neighbours, exhibiting calcium signalling across their extended leaves. The researchers discovered that compounds Z-3-HAL and E-2-HAL induced calcium signals in Arabidopsis by analysing airborne compounds.

Using Arabidopsis plants engineered with fluorescent sensors in specific cells, they identified that guard cells (forming stomata), mesophyll cells (inner leaf tissue), and epidermal cells (outermost layer) were the initial responders to danger cues.

Watch the video below:

When exposed to Z-3-HAL, guard cells promptly generated calcium signals, followed by mesophyll cells. Additionally, pre-treating plants with a phytohormone that closes stomata significantly reduced calcium signalling, indicating stomata function as the plant's 'nostrils.'

"We have finally unveiled the intricate story of when, where, and how plants respond to airborne 'warning messages' from their threatened neighbours," says Masatsugu Toyota, a molecular biologist at Saitama University in Japan and senior author of the study.

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

(With inputs from agencies)