Wearable devices not just for humans anymore –– try plants

It’s the age-old dilemma of those with a kitchen garden or the decorative potted plants on the balcony—when to water the plants and how much. And sometimes even the farmer with a large area of farmland trying to keep track of the water needs of his crops.

But despair not, science has a solution— a wearable device for plants that can wirelessly transmit data to a smartphone app, allowing remote management of drought stress in gardens and crops.

The scientific breakthrough by researchers at the Brazilian Nanotechnology National Laboratory has been reported in the American Chemical Society (ACS) Applied Materials & Interfaces.

Wearable devices for humans are now part of our daily lives—from heart rate monitors to jogging counters that track the number of steps taken and calories burnt. Doctors can now monitor a patient’s health through similar wearable devices that seamlessly transmit data to an app or website.

The new device developed for plants works on the same principle and technology. Just like human wearable devices, plant wearables can help farmers and gardeners remotely check up on the plants’ health, and could also raise the alarm when the leaves are lacking water –– the key marker of metabolism and drought stress.

“Because the water content is a key marker of leaf health, monitoring of the LWC [leaf water content] can lend key insights into daily practice in precision agriculture, toxicity studies, and the development of agricultural inputs,” wrote the authors of the research. 

Researchers in earlier years had developed metal electrodes to monitor plants, but they didn’t remain attached and as such were not a reliable source of data. 

That’s why Renato Lima, at the Brazilian Nanotechnology National Laboratory, and his colleagues wanted to come up with an electrode design that was reliable for long-term monitoring of plants’ water stress while also remaining in place.

The researchers tested two types of electrodes: one was a nickel electrode that looked like a thin, squiggly line, and the other was cut from partially burnt paper that was coated with a waxy film.

The team attached both electrodes to cut soybean leaves with clear adhesive tape. They found that the thin squiggly nickel electrodes outperformed the wax-film coated partially burnt paper electrodes, producing larger signals as the leaves dried out.

Moreover, the nickel electrodes also stuck to the soybean leaves better than the paper ones, perhaps because their squiggly design allowed more of the adhesive tape to contact the leaf surface.

Having determined that nickel electrodes performed better, the researchers then created a plant-wearable device and attached it to a living plant in a greenhouse. The device wirelessly shared data via a smartphone app and website, and the researchers set up a simple, fast machine learning technique to successfully convert the data into the percent of water content lost by the plant.

The researchers say that the plant-wearable device can not only tell us about water content on the leaves, but that it can also indirectly advise whether the plant is exposed to plants and toxic agents.

Having tested the plant-wearable device with nickel electrodes on plants indoors and gotten satisfactory data, the scientists now have set their sights on outdoor gardens and crops so that the device can tell us when plants need to be watered. This would, the news release says, potentially save resources and increase yields.

“These platforms can provide key information for aiding efficient data-driven management and guiding decision-making steps,” the authors wrote.

So, the next time you see the leaves on your plants shrivelling, think about getting them the latest gadget. However, it’s not immediately known if and when these breakthrough plant devices would be available in the market or how much they would cost.