New circuits use live lettuce seedlings as conductors

MIT Technology Review : The electrical properties of plants have only been of occasional interest to researchers, but a new paper suggests that plants may be useful in simple circuitry. Andrew Adamatzky of the University of the West of England in Bristol and his colleagues created circuits using lettuce seedlings and measured the resistance across the plants. The average resistance of 2.76 MΩ was significantly higher than that of conventional conductors, but was lower than the resistance of other living organisms that have been used in circuits, such as slime molds. Slime molds, however, tend to be hard to grow and maintain. The researchers also found that the electrical properties of the seedlings experienced oscillations that they think were related to the cytoplasmic flow that transmits nutrients through the plant. Adamatzky hopes to be able to grow the seedlings into circuits directly, but has been unsuccessful in controlling the direction of their growth. Applications for plant-based circuits aren’t clear, but because their resistance may be sensitive to heat and cold, they could prove useful as temperature sensors. They may also be used in unconventional computing in ways similar to slime molds, which have the ability to extract and process information from their environment.