A team of Singapore-based scientists has developed a device that can deliver electrical signals to and from plants, opening the door to a range new possibilities.
The Singapore NTU research team developed their plant ‘communication’ device by attaching a conformable electrode (a piece of conductive material) on the surface of a Venus flytrap plant, using a soft and sticky adhesive known as hydrogel.
With the electrode attached to the surface of the flytrap, researchers achieved two things - picked up electrical signals to monitor how the plant responds to its environment; and transmitted electrical signals to the plant to cause it to close its leaves.
Scientists have known for decades that plants emit electrical signals to sense and respond to their environment.
The research team believe that developing the ability to measure the electrical signals of plants could create opportunities for a range of applications, such as monitoring the health of crops and developing plant-based robots.
However, plants’ electrical signals are very weak and can only be detected when the electrode makes good contact with plant surfaces.
The hairy, waxy and irregular surfaces of plants make it difficult for any thin-film electronic device to attach and achieve reliable signal transmission.
To overcome this challenge, the team drew inspiration from the electrocardiogram (ECG), which is used to detect heart abnormalities by measuring the electrical activity generated by the organ.
As a proof of concept, the scientists took their plant ‘communication’ device and attached it to the surface of a Venus flytrap - a carnivorous plant with hairy leaf lobes that close and trap insects when triggered.
The device has a diameter of 3mm and is harmless to the plant. It does not affect the plant’s ability to perform photosynthesis while successfully detecting electrical signals from the plant.
Using a smartphone to transmit electric pulses to the device at a specific frequency, the team made the Venus flytrap close its leaves on demand in 1.3 seconds.
The researchers have also attached the Venus flytrap to a robotic arm and, through a smartphone and the ‘communication’ device, stimulated its leaf to close and pick up a piece of wire half a millimetre in diameter. Watch the video below.
Their findings, published in the scientific journal Nature Electronics in January, demonstrate the prospects for the future design of plant-based technological systems, say the research team.
Their approach could lead to the creation of more sensitive robot grippers to pick up fragile objects that may be harmed by current rigid ones.
Crop health monitoring
The research team envisions a future where farmers can take preventative steps to protect their crops, using the plant ‘communication’ device they have developed.
Lead author of the study Chen Xiaodong, president's chair professor in materials science and engineering at NTU Singapore, said: "Climate change is threatening food security around the world. By monitoring the plants’ electrical signals, we may be able to detect possible distress signals and abnormalities.
“When used for agricultural purposes, 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 maximise crop yield for the population,” he concluded.