Graphene ‘tattoo’ could make drought-resistant plants a reality

Plant breeders could soon have access to an innovative new tool that will measure the water intake of individual plants, allowing them to choose parent stock which can better survive in conditions with limited amounts of water.

Made from graphene only a single atom thick, the stick-on sensors, are being described by researchers as a “plant tattoo”.

“The ultimate goal of our work is to develop drought-tolerant crops that can deal with climate change,” said Electrical Engineer at Iowa State University, Dr Liang Dong, who led the study.

To create the sensors, a thin piece of clear tape is embedded with multiple layers of graphene flakes arranged in a patterned design, with certain patterns used strategically, based on their ability to conduct electricity.

The sensors are applied to plant leaves and attached to small wires connected to a battery device which sends an electrical current through the sensor that changes depending on how fast water moves up the plant.

As plants consume water from the soil, water vapour escapes from the tiny holes in their leaves known as the stomata. By measuring how much the electrical current slows, the sensor indicates how quickly the plant is taking up moisture from the soil.

In the initial testing, on corn plants, the researchers measured how long it took for two varieties to consume water, first from their roots to their lower leaves, and then again to their upper leaves. The difference was pronounced, with one variety taking 80 minutes on average, and the other taking an average of only 28 minutes, providing a clear indication of which variety would be more resilient in drier conditions.

Graphene is a sheet of carbon that conducts electricity and is mechanically strong. The chemical compound used to develop the sensor was graphene-oxide, as it is particularly sensitive to moisture.

Photo credit: Dr Liang Dong/Iowa State University.

Source: Science News for Students, made possible with generous support from the Lemelson Foundation.