You mightn't know it from the outside looking in, but plants are complex organisms that use electrical signals to sense and respond to their surroundings. We've previously seen imaginative scientists harness these capabilities to produce cyborg plants that drive themselves toward light or act as environmental biosensors, and new research out of Singapore's Nanyang Technological University (NTU) shows how they might even be used to pick up fragile objects, among some other interesting possibilities.
While it is well known that plants, like many living organisms, emit electric signals in response to external stimuli, these electric signals are very weak. The NTU team came up with a way to get a loud and clear reading of these transmissions by taking inspiration from the electrocardiograms (ECGs) used to monitor heart health via electrical activity in humans.
To adapt this type of tech for plants, the researchers developed a conformable electrode material and combined it with an adhesive hydrogel that transforms from liquid to a stretchy gel at room temperature. This enabled electrode to be attached to a wide range of plants, even as they grew and moved in response to their environment. Here, it acts as a communication device that offers a clear reading of the electrical signals the plants emit.
"Climate change is threatening food security around the world," says lead author of the study Chen Xiaodong. "By monitoring the plants' electrical signals, we may be able to detect possible distress signals and abnormalities. When used for agriculture purpose, farmers may find out when a disease is in progress, even before full‑blown symptoms appear on the crops, such as yellowed leaves. This may provide us the opportunity to act quickly to maximize crop yield for the population."
This device has a diameter of just 3 mm and importantly, doesn't impact the plant's ability to carry out photosynthesis. In one of its initial experiments, the team took an early version of the technology and planted it on a Venus flytrap. Using a smartphone, the team then sent electric pulses to the device at specific frequency, which prompted the Venus flytrap to close its leaves on demand.
In another round of experiments, the team attached a robotic arm to the Venus flytrap. Repeating the process and pulsing electrical signals from a smartphone at specific frequencies caused the Venus flytrap to close, ensnaring a fine piece of wire in the process.
Through these experiments, the team demonstrated not just how its communication device can be used to monitor the way plants are responding to their surroundings, but actually use them as sensitive robotic grippers for fragile objects. The team is now exploring other ways these capabilities could be put to use.
The scientists published their research across two studies, one in the journal Nature Electronics and the other in Advanced Materials, while the video below offers a look at the technology in action.
Source: Nanyang Technological University
