MIT nanosensor tells a smartphone when plants are stressed

Engineers at MIT have developed a new method of tracking how plants respond to stressors such as injury, infection, and light damage. The injuries are tracked using sensors made of carbon nanotubes. The small sensors can be embedded in plant leaves where they can report on hydrogen peroxide signaling waves.The researchers say that plants use hydrogen peroxide to communicate within their leaves, sending out a distress signal that stimulates leaf cells to produce compounds that will repair damage or repel predators like insects. The MIT sensors can use the hydrogen peroxide signal to distinguish between different types of stress as well as between different species of plants.

The engineers say that the sensor has the potential to be used to study how plants respond to different types of stress, and to help agricultural scientists develop new strategies to improve crop yields. So far, the researchers have demonstrated their approach using eight different plant species. In testing, the scientists used spinach, strawberry plants, and arugula among others.

The team believes the sensor could work in additional plant species. The team used a method called lipid exchange envelope penetration to incorporate the sensors in the plant leaves. While trying to learn to embed the sensors into the plant leaves, one of the scientists accidentally damaged the plant and was able to witness the hydrogen peroxide being released at the wound site.

The team says that as the plant cell releases hydrogen peroxide, a calcium release is triggered within adjacent cells to stimulate those cells to release more hydrogen peroxide. The flood of hydrogen peroxide stimulates plant cells to produce molecules called secondary metabolites to help repair the damage. Some plants also secrete other secondary metabolites to fend off predators. Applications for the tech include screening different plant species for their ability to resist mechanical damage or how plant species respond to pathogens.