The Venus Flytrap (Dionaea muscipula) is already a fascinating plant, but scientists have discovered another amazing thing about it: It generates measurable magnetic fields as the leaves close.
And go much further D. muscipulathe latest research could teach us a lot about how plants use magnetic field signaling to communicate and as an indicator of disease (something we also see in humans and other animals).
Plants are known to use electrical signals as a kind of nervous system, but capturing biomagnetism was difficult.
A 2011 study attempted to detect a magnetic field around a Titan arum (Amorphophallus titanium) – that big, highly smelly plant – using atomic magnetometers capable of detecting the smallest fluctuations.
That study found that the plant did not generate a magnetic field greater than one-millionth of the strength of the magnetic field that surrounds us on Earth, so the experiment was considered a failure.
The researchers involved in the 2011 study said their next steps, if they took them, would be to focus on a smaller plant.
For the new study, a different group of researchers has indeed gotten smaller.
“We have been able to show that action potentials in a multicellular plant system produce measurable magnetic fields, something that has never been confirmed before,” says physicist Anne Fabricant of Johannes Gutenberg University of Mainz (JGU) in Germany.
Place Venus fly traps under observation. (Anne Fabricant)
These “action potentials” are rapid bursts of electrical activity, and the Venus flycatcher can have multiple triggers: if the plant is touched, injured, affected by heat or cold, or charged with liquid, action potentials can be activated.
Here the researchers used heat stimulation to activate the electrical activity, and a glass cell magnetometer to measure magnetic disturbances. This approach not only kept background noise to a minimum, but had advantages over other techniques in that it could be miniaturized and did not require cryogenic cooling.
The measured magnetic signals went up to an amplitude of 0.5 picotesla, comparable to nerve impulses firing in humans and millions of times weaker than Earth’s magnetic field – a tiny ripple, but a detectable one.
“You could say that the research 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 using 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 any invasive procedure.
With the help of this current research, the same type of scanning could now also be possible in plants: crops can be scanned for temperature shifts, chemical changes or pests without, for example, damaging the plants themselves.
And we can add the findings to our growing knowledge of how plants transmit signals, both internally and externally, and communicate through a hidden network that scientists are just beginning to investigate.
“In addition to 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-range electrical signals in a variety of plant species, and to develop non-invasive diagnostics for plant stress and disease.”
The research is published in Scientific reports