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A recent study (Scientific Reports) from Germany found that the Venus flytrap (Dionaea muscipula) plant is capable of generating small magnetic fields. When these plants send electrical signals to trigger the closure of their traps, to catch an insect, a biomagnetism phenomenon was observed. The leaf stalk, or petiole, is not excitable and is electrically insulated from the trap.

The first author of the study Anne Fabricant explained in a release that the magnetic signals in plants are very weak and it was extremely difficult to measure them with the help of older technologies. Using new and advanced atomic magnetometers, the team was able to measure the magnetic signals, which had an amplitude of up to 0.5 picotesla, which is millions of times weaker than the Earth’s magnetic field. “The signal magnitude recorded is similar to what is observed during surface measurements of nerve impulses in animals,” explains Fabricant.

Interestingly, the trap is electrically excitable in a variety of ways: in addition to mechanical influences such as touch or injury, osmotic energy, for example salt-water loads, and thermal energy in the form of heat or cold can also trigger action potentials.

Though biomagnetism has been studied in humans and animals, it has not been explored much in plants and the team now aims to measure these small signals from other plant species. They hope that this can help in identifying how the plant responds to sudden temperature changes, chemicals, and pest attacks.