A Singaporean team has developed a device that uses electric signals to 'talk' to plants. 

For generations, scientists have been fascinated by the Venus flytrap's (Dionaea muscipula) unusual shape and characteristics. "One of the most magnificent [plants] in the world," wrote Charles Darwin. He was enthralled by the plant's ability to adapt to nutrient-poor, harsh environments and live and evolve.

Many decades later, Jagadish Chandra Bose, a plant physiologist among other things, noticed that the plant's leaves were sensitive to touch and created electrical impulses, which were similar to the signals produced by our bodies.

Researchers at Singapore's Nanyang Technological University (NTU) have now discovered a method to manipulate these electrical impulses. They've created an electronic system that can send electrical impulses to plants and receive signals in return, all of which is controlled by a smartphone app.

Farmers might use their technology to 'speak' with their plants and learn about damage caused by pests and/or environmental stress, according to the scientists. In January 2021, the study's findings were published in a publication.

Materials scientist Xiaodong Chen was in charge of the team. They began by developing a conformable electrode, which is a conductive substance that can be bent or softly squeezed to change its shape. Using a hydrogel glue, they attached it to a waxy leaf of a Venus flytrap plant. Hydrogels are light-weight polymers that can contain a lot of water.

The electrode serves as a window via which plant signals are sent to the smartphone app and vice versa. It intercepts electric impulses travelling through the plant, which the app may decipher to imply a variety of things depending on their intensity, frequency, timing, and other factors. In a report published in March, Chen and his colleagues revealed how it was put together. 

"A translucent sheet serves as the soft electrode on the Venus flytrap. In an email to The Wire Science, Chen said that it's basically a 'signal translator' between plants and humans. "Imagine it as a stethoscope that physicians use to detect information within their patients' bodies."

Attaching the 'soft electrode' to a Venus flytrap plant, he claims, transformed it into a 'soft robot' capable of accepting commands and relaying data. The plant's jaw-like sections at the ends of its leaves, for example, may be used to 'grab' tiny items. "We're currently looking at what other duties the robot can perform," Chen added.

Similarly, the electrode might detect any distress signs – such as extreme heat or soil salinity – before the plant manifests visible symptoms, allowing the farmer to intervene sooner and save money.

Pesticides, chemical fertilisers, and mechanisation are used to safeguard crops in most agricultural operations, and their usage is "based on a farmer's own experiences," according to the report. According to Chen, farmers who use the resources at their disposal in an inefficient manner as a result of this subjective judgement.

The NTU team thinks that by placing a "cluster" of sensors in a field of plants, each sensor can describe the micro-environment shared by a group of plants, whose demands can then be handled by the information sent by the sensors, waste may be reduced.

Pesticides, chemical fertilisers, and mechanisation are used to safeguard crops in most agricultural operations, and their usage is "based on a farmer's own experiences," according to the report. According to Chen, farmers who use the resources at their disposal in an inefficient manner as a result of this subjective judgement.

The NTU team thinks that by placing a "cluster" of sensors in a field of plants, each sensor can describe the micro-environment shared by a group of plants, whose demands can then be handled by the information sent by the sensors, waste may be reduced.

Arunendra Nath Lahiri Majumder is a plant biotechnologist at the Bose Institute in Kolkata, where he studies paddy's reactions to environmental stress. He wasn't part of the NTU study and believes that in the case of paddy, plant-based electrodes "would be an a priori hypothesis needing a proof of concept."

According to him, the Venus flytrap's sensory systems are substantially different from those of rice, which does not move. "In reality, plants like the Venus flytrap, Mimosa pudica, Nepenthes sp., or Desmodium demonstrate specific motions that are tailored to their physiology," Majumder told The Wire Science.

"These effects are thought to be caused by electrical conductivity in connected cells or tissues that are unique to each plant." Despite extensive investigation, the molecular phenomenon [underlying] the sensing process for other plants, such as rice, has yet to be established."

"Plants do definitely contain many different forms of messages," Chen said, adding that their present approach only applies to electrical signals, not chemical, optical, or auditory signals. "We intend to increase our device's functionality to new signal kinds so that we can better comprehend plants," he added.

Chen's team speculated on a range of potential uses in their published research. "The capacity to interfere with a plant's electrophysiology by external electrical stimulation presents new opportunities for creating plant communication protocols," they write in one place.

However, any agricultural revolution ushered forth by such technologies will have to wait. According to Majumder, the NTU's notion has to be investigated and tested further, and that it is "premature" in its current form.