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Magnetic Fields Detected in Venus Flytraps

Researchers used sensitive instruments to measure weak magnetic fields when the flytrap’s ‘jaws’ closed up

Correspondent

February 10, 2021

When the vegetal “jaws” of the carnivorous Venus flytrap plant snap shut, they produce a small magnetic field, according to new research published last month in the journal Scientific Reports. This discovery is one of very few magnetic fields ever detected in plants, reports Yasemin Saplakoglu for Live Science.

Researchers in Berlin used a sensitive instrument called an atomic magnetometer inside a special room that blocks out the modern world’s electromagnetic chatter to detect the magnetic fields emanating from the plants, reports Isaac Schultz for Gizmodo.

The magnetic field the researchers’ equipment picked up coming from the Venus flytraps (Dionaea muscipula) is more than a million times weaker than Earth’s, according to Live Science.

The magnetic field likely comes from electrical impulses called action potentials that trigger the closure of the flytrap’s leaves, Anne Fabricant, a physicist at the Helmholtz Institute in Germany and lead author of the research, tells Live Science. "Wherever there is electrical activity, there should also be magnetic activity," Fabricant tells Live Science.

The so-called biomagnetism that emerges from the electrically charged firing of nerves has been studied extensively in the human brain and other animals, but is less well understood in plants, which don’t have nerves but can still generate action potentials.

"You could say the investigation is a little like performing an MRI scan in humans," says Fabricant in a statement. "The problem is that the magnetic signals in plants are very weak, which explains why it was extremely difficult to measure them with the help of older technologies."

A flytrap’s spikey, jaw-like leaves close up like a bear trap if a fly or other suitably dainty prey item brushes against at least two of the sensitive hairs stationed inside the trap which in turn initiate an action potential.

For their study, Fabricant and her team used heat to stimulate action potentials in isolated flytrap leaves, according to the statement. When the leaves were triggered, the action potentials created a magnetic field with a strength of 0.5 picoteslas—comparable to nerve impulses in animals, per the statement.

According to Gizmodo, prior to these results scientists had only detected magnetic fields in two other plants—a single-cell algae and a bean plant.

"It's exciting to demonstrate plant-biomagnetic measurements using atomic magnetometers, which operate at room temperature and can be portable and miniaturized," says Fabricant in the statement. "The fact that we were able to detect magnetic fields gives some hints about how electric currents are distributed in the trap."

Future experiments will look to detect magnetic fields in other species of plants. Per the statement, the ability to measure the faint electrical signals used by plants could one day be used to monitor crop plants’ responses to temperature, pests or chemicals.