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Singapore Team Builds Device to ‘Talk’ to Plants Through Electric Signals

Singapore Team Builds Device to ‘Talk’ to Plants Through Electric Signals

A Venus flytrap plant. Photo: Andi Superkern/Unsplash

  • The team says their invention could help farmers ‘communicate’ with their plants and learn about damage due to pests and/or environmental stress.
  • The device consists of a soft electrode attached to the leaves of a Venus flytrap plant using a hydrogel adhesive, linked by wires to a smartphone app.
  • The invention is currently limited by the fact that Venus flytrap plants ‘communicate’ differently than farmed crops, and plants also use other types of signals.

Kolkata: The curious form and features of the Venus flytrap (Dionaea muscipula) have intrigued scientists for centuries. Charles Darwin described it as “one of the most wonderful [plants] in the world”. He was fascinated by how the plant survived and evolved by adapting itself in nutrient-poor, adverse habitats.

Many decades later, Jagadish Chandra Bose, a plant physiologist among other things, observed the plant’s leaves were sensitive to touch, and generated electrical impulses – much like the signals in our bodies.

Now, researchers at Nanyang Technological University (NTU), Singapore, have found a way to control these electrical impulses. They have developed an electronic system that can deliver electrical signals to plants and receive signals back, processed through a smartphone application.

According to the team, their invention could help farmers ‘communicate’ with their plants and learn about damage due to pests and/or environmental stress. The paper describing the study was published in January 2021.

The researchers were led by materials scientist Xiaodong Chen. They first created a conformable electrode – a piece of conductive material whose shape could be modified in simple ways, like bent or lightly compressed. They fixed it on the waxy leaf of a Venus flytrap plant using a hydrogel adhesive. Hydrogels are polymers that can hold a large amount of water and are very light.

This way, the electrode acts as a window through which plant signals are sent to the smartphone app, and vice versa. It intercepts electric signals moving through the plant, which the app can decode to mean different things based on their strength, frequency, timing, etc. Chen and his colleagues described its construction in a different paper published in March.

“The soft electrode on the Venus flytrap is a transparent film. It is actually a ‘signal translator’ between plants and human beings,” Chen said in an email to The Wire Science. “You can think of it as a stethoscope used by doctors to sense information inside the body of patients.”

According to him, attaching the ‘soft electrode’ to a Venus flytrap plant turned it into a ‘soft robot’ – capable of receiving instructions and relaying data. The plant could be used to ‘catch’ small objects using the jaw-like portions at the ends of its leaves, for example. “We are now exploring more tasks the robot can do,” Chen wrote.

Similarly, the electrode could also pick up on any distress signals – such as excessive heat or soil salinity – before the plant shows outward symptoms, allowing its grower to act sooner and reduce waste.

“Most agricultural practices rely on pesticides, chemical fertilisers and mechanisation to protect the crops” – and their use is “based on a farmer’s personal experiences.” This subjective evaluation, Chen added, leads to farmers using the resources at their disposal in suboptimal fashion.

The NTU team believes it can cut down such waste by deploying a “cluster” of sensors in a field of plants such that each sensor can describe the micro-environment shared by a group of plants, whose needs can then be managed by what the sensors relay.

Arunendra Nath Lahiri Majumder, is a plant biotechnologist at Bose Institute, Kolkata, where he has been studying environmental stress responses in paddy. He wasn’t involved in the NTU study, and thinks that at this stage, plant-based electrodes “would be an a priori hypothesis awaiting a proof of concept” in case of paddy.

According to him, the sensory mechanisms of the Venus flytrap are quite different from those of rice, which doesn’t show any observable movement. “In fact, plants like Venus flytrap, Mimosa pudicaNepenthes sp. or Desmodium show certain characteristic movements to suit their physiology,” Majumder told The Wire Science.

“Such effects are believed to originate from the electrical conductivity in associated cells or tissues typical of each plant. Despite intense research in this area, the cellular phenomena [underlying] the sensory mechanism are yet to be determined for other plants like rice.”

Chen agreed, saying, “Plants indeed contain many different types of signals” and their current technique applies only to electrical signals, not chemical, light, acoustic, etc. “We hope to expand the capability of our device to more signal types so that we can understand plants better,” he said.

In its published paper, Chen’s team speculated on a variety of potential applications as a result. “In particular,” they write in one place, “the ability to interfere with a plant’s electrophysiology through external electrical stimulation opens new possibilities for building plant communication protocols.”

But any agricultural revolution that such a technology may herald will have to wait. According to Majumder, the NTU’s idea will have to be further studied and tested, and that the idea in its current form is “premature”.

Chandana Chandra is a freelance science journalist based in Kolkata.

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