Venus flytrap (Dionaea muscipula) is already a fascinating enough plant, but scientists have discovered something amazing about it: it generates measurable magnetic fields as its leaves close.
And going beyond D. muscipula, the latest research could teach us a lot about how plant life uses magnetic field signaling to communicate as an indicator of disease (which we see in humans and other animals).
It is well known that plants use electrical signals as a kind of nervous system, but capturing biomagnetism has been difficult.
A 2011 study attempted to detect a magnetic field around a Titan arum (Amorphous titanium) – that big, very smelly plant – using atomic magnetometers that are able to detect the slightest fluctuation.
This study revealed that the plant did not generate a magnetic field greater than one millionth of the strength of the magnetic field around us on Earth, resulting in the experiment considered a failure.
The researchers involved in the 2011 study said that their next step, if any, would be to focus on a smaller plant.
For the new study, another group of researchers did shrink.
“We have been able to show that the action potentials in a multicellular plant system produce measurable magnetic fields, which has never been confirmed before,” says physicist Anne Fabricant of Johannes Gutenberg University in Mainz (JGU), Germany.
Putting Venus’ traps under observation. (Anne Manufacturer)
These “action potentials” are rapid explosions of electrical activity, and the Venus muscle can have several triggers: If the plant is touched, injured, affected by heat or cold or loaded with liquid, then the action potentials can be triggered.
Here the researchers used heat stimulation to activate electrical activity and a glass cell magnetometer to measure magnetic disturbances. This approach not only minimized background noise, but had advantages over other techniques in that it could be miniaturized and did not require cryogenic cooling.
The measured magnetic signals amounted to an amplitude of 0.5 picotesla, comparable to the nerve impulses that are triggered in humans and millions of times weaker than the Earth’s magnetic field – a small but detectable wave.
“You could say that the investigation is a bit like performing an MRI scan on humans,” says Fabricant. “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.”
In addition to MRI scans, other techniques such as electroencephalography (EEG) and magnetoencephalography (MEG) are used to measure magnetic fields in humans, potentially identifying problems without invasive procedures.
With the help of this current research, the same type of scanning could now be possible with plants: crops could be scanned for temperature changes, chemical changes or pests, without the need to damage the plants themselves, for example.
And we can add the findings to our growing knowledge of how plants send signals both internally and externally, communicating through a hidden network that scientists are just beginning to explore properly.
“Beyond the proof of principle, our findings pave the way for understanding the molecular basis of biomagnetism in living plants,” the researchers write in their published paper.
“In the future, magnetometry can be used to study long-distance electrical signaling in a variety of plant species and to develop noninvasive diagnoses of stress and plant diseases.”
The research was published in Scientific reports.