Do plants have some kind of nervous system? This is difficult to establish as there are no suitable measurement methods around. Plant researchers from Würzburg used aphids for this purpose – and discovered that plants respond differently to different kinds of damage.
When a plant is mechanically injured or exposed to cold, it will send electrical signals through its body. In both cases, the signals cover large distances of as much as ten centimetres and more. The signals travel from the areas that have been injured or exposed to cold to all other organs which then react accordingly, for example by synthesizing proteins that protect the plant against cold.
Electrical signals travel alongside the sieve tube elements of plants.
Picture: Rosalia Deeken / Sönke Scherzer /Christian Wiese
An injury triggers totally different electrical signals than a cold shock. Biophysicist Professor Rainer Hedrich of the Julius-Maximilians-Universität Würzburg (JMU), Germany, and his team made this discovery using the model of thale cress (Arabidopsis thaliana).
A cut injury at a leaf triggers relatively slow electrical pulses over several minutes. Exposure to cold, in contrast, causes quicker pulses about 15 seconds long. "These differences indicate that the electrical signals each have a specific meaning," Hedrich further.
Electrical signals at the sieve tubes
Could this principle be similar to that of the human nervous system? Here, electrical signals travel alongside specialized cells, bridge synapses and ultimately trigger a response in the body. Plants, however, do not have a brain, nor nerve cells or synapses. According to Hedrich, there is hence no serious scientific evidence to attribute intelligence to plants and proclaim a "plant neurobiology".
Nevertheless, many researchers today are convinced that plants also use electrical signals to exchange information between the organs of their body. Hedrich's work on the Venus flytrap has even demonstrated that the carnivorous plant is capable of counting the electrical signals sent and make decisions based on this.
Such signals can be measured in the sieve tube elements which form a system of interconnected cells that pervades the entire plant like a vascular system and usually transports sugar and other substances.
Measuring signals difficult previously
Are the sieve tubes the "green power cable" or even some kind of "nervous system of the plant? This assessment is controversial – due to a methodical issue among others: So far, scientists have not had the proper tools to measure the transmission of electrical signals in plants over longer distances.
Rainer Hedrich, Vicenta Salvador-Recatalà and Ingo Dreyer have now developed an elegant solution to this problem which they publish in the science magazine “Trends in Plant Science”: The plant scientists used aphids as biosensors. They enhanced a method that has been known since 1964 which involves an electric circuit being generated between the aphid and the plant.
Aphids allowed to suck for the benefit of research
How that works? Aphids puncture the phloem vessels of plants and suck the sugary sap. If a fine wire is glued to their body and connected to an electrode sitting in the earth of a potted plant, an electric circuit is created between aphid and plant. It allows measuring how the electrical signals propagate in the sieve tubes.
This method will now be used to answer a number of questions. How and where are the signals created? What kind of information do they carry? Where are they registered and what reactions do they trigger? So there is still plenty of work for the Würzburg scientists to do – as well as for the plant lice that puncture and suck in the name of science.
“Electrical Wiring and Long-Distance Plant Communication”, Rainer Hedrich, Vicenta Salvador Recatalà, Ingo Dreyer, Trends in Plant Science, 12 February 2016, DOI: 10.1016/j.tplants.2016.01.016
Prof. Dr. Rainer Hedrich, Department of Botany I of the University of Würzburg, Phone: +49 931 31-86100, firstname.lastname@example.org
Robert Emmerich | Julius-Maximilians-Universität Würzburg
Colorectal cancer risk factors decrypted
13.07.2018 | Max-Planck-Institut für Stoffwechselforschung
Algae Have Land Genes
13.07.2018 | Julius-Maximilians-Universität Würzburg
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
13.07.2018 | Event News
13.07.2018 | Materials Sciences
13.07.2018 | Life Sciences