Magnetic fields produced by the venus fly trap have been measured by an interdisciplinary team of scientists. Lily Sharratt-Davidson explores the impact these findings could have on plant diagnostics.
The venus flytrap (or Dionaea Muscipula) is a well-recognised carnivorous plant – infamous for its ability to capture small insects inside its cage-like leaves. This unusual method of hunting works using a system of action potentials; electrical signals similar to nerve impulses in humans or animals. When an insect lands on the leaves it brushes against tiny trigger hairs. Once two or more of them are touched an electrical impulse is generated which causes the trap to snap shut, encasing it’s meal for digestion. Previously, this signal has only been measured by placement of electrodes on the leaves of the plant. However this method is fallible, with the flytrap becoming damaged and the electrode position strongly influencing the signals produced.
This unusual method of hunting works using a system of action potentials; electrical signals similar to nerve impulses in humans or animals.
A team of scientists have now successfully measured the action potential effect using the magnetic fields generated by the electrical impulse. This was done by artificially triggering the action potentials, which other than motion can be set off by high salt levels or temperature. In this instance the researchers used high temperatures to trigger the trap, avoiding the unwanted field interactions that the mechanical stimulation causes. In a magnetically shielded room, atomic optically pumped magnetometers were used to measure the generated fields. These devices contain a glass tube filled with alkali vapours and operate on the basis of the Zeeman effect, which states that in a magnetic field the energy levels of an atom are split into a greater number of levels than usual. Electrons in an atom reside in these energy levels, and can be pumped to higher ones by exposure to specific wavelengths of light. Consequently, the magnetic field strength can be determined by measuring the energy required to populate different levels with electrons. The measured results were described as “comparable to what one observes in surface measurements of nerve impulses in animals” by Anne Fabricant, a research scientist at the Helmholtz Institute and Johannes Gutenberg University of Mainz and part of the team that completed this research. This highlights the effectiveness of this technique, and draws a parallel with more familiar diagnostic procedures such as Magnetic Resonance Imaging.
While much is known about the methods of nerve signal transportation in animals and humans, much less is known about action potential pathways in plants; although the results of this research shed some light onto the proposed propagation of electrical signals between plant cells of the venus flytrap. By applying the measured magnetic field magnitudes to resistance calculations the researchers were able to show that their results agree with an existing hypothesis that the signals transport through the electrically conductive phloem in the plant’s vasculature. The applications of this research show the potential magnetometry has for studying long distance electrical signalling in a variety of plant species, not only the venus fly trap.
Aside from exploring the characteristics of this extraordinary plant, this technique could have serious implications for the future of crop diagnostics. Previously, magnetic fields in other plant species have been measured using Superconducting-Quantum-Interference-Device magnetometers; bulky devices that require cooling to cryogenic temperatures. This new method is more transportable, and allows for measurements of smaller biological features with greater accuracy. Successfully applying this to other species could lead to a whole new tool in plant diagnostics and study. In a world where crop security is vital, the demonstration of this new, non-invasive technique is not only exciting but advantageous. In the future this method could potentially be developed to measure the electromagnetic response of plants to sudden challenges in their environments. This could be utilised to monitor their response to chemical exposure, temperature changes, or attacks by herbivores, and so allow us not only to understand but to grow and nurture plants more efficiently. The advantages of such a scenario are obvious; from continuing research into action potential pathways in rare and unusual plant species to increasing efficiency in crop diagnosis and growth.
Written by Lily Sharratt-Davidson and edited by Shona Richardson
Lily Sharratt-Davidson is a first year Physics student. Find her on LinkedIn @Lily Sharratt-Davidson