This is an old revision of the document!

Plant Neurobiology

Definition and origin of the term

Plant neurobiology studies how plants interpret external stimuli and convert them into internal electro-chemical signals.

The term 'plant neurobiology', was introduced recently in the scientific literature. It refers to the fact that similarities exists between the ways internal signals are transmitted in plants and animals. Strictly speaking, plants does't have real neurons, so the use of the word 'neurobiology' in this context can be seen as a metaphore or as an analogie (Barlow, 2008).
For this reason, some authors consider this terminology as illegitimate, and fear that it could only bring confusion and misunderstanding in the field of plant signalling. However, the association of the words 'plant' and 'neurobiology' can also be seen as an invitation to broaden the definition of what a nervous system actually is, and to take distance from the classical view of a plant as an inanimate and passive organism.
It is now largely accepted that electrical signals are transmitted via the plant's phloem and allow the rapid propagation of information between remote parts of the plant, especially in reaction to an external stress. Those electrical signals has to be interpreted by a specialized molecular machinery at the location where it is supposed to produce an effect. The analogy with the animal's nerve is then easy to be made :

« Phloem is an electrical conductor of bioelectrochemical impulses over long distances . . . structures of phloem and axon can be pictured as hollow tubes filled with electrolyte solutions » (Volkov, 2000)

Some keywords :

Phloem, Xylem, Neuron, Axon

The signalling systems in plants

Plants use a lot of chemical signals to regulate their growth, metabolisms and to adapt to external constraints. In the last decades, the study of the key molecules such as auxins, growth regulators, morphogens and other plant hormones has shown a lot of similarities with the animal's hormonal system. The existence of electrical signals in plants, which has been suspected since the '70 (see : the Secret Life of Plants), is now being widely recognized by the scientific community.

It has been shown that the vascular tissues of plants (phloem and xylem) plays a central role in the plant's 'neural' structure. They do not only convey nutients, water and hormones but also electrical impulses through the plant's structrure.

There are two types of electrical impulses in the plant :

* The action potentials have been shown to be involved in many internal regulation processes (growth synchronization, modulation of auxin metabolism, sensing of hydraulic signal, some 'moving' reactions, etc.), and are transmitted via the phloem. The term 'action potential' actually comes from the classical neurobiology.

* The slow wave potential (also called variation potential) are induced in case of more severe wounds, and seem to be transmitted via the xylem.

The action potentials are largely documented in the scientific literature and the most famous manifestation of it is the rapid reaction of 'sensitive' plants such as Mimosa pudica or the insect trap of Dionaea muscipula.

Origin of the similarities between the signalling systems in plants and animals

Between two living organisms, a similarity can be explained by a process of convergent evolution (in that case we speak about an homoplasy) or by the existence of a common ancestor that already presented that certain feature.

A question that arise here is wheter the 'similar' neural system of plants and animals can be explained as pure homoplasies or could be partially explained via their common origin. The latter hypothesis implies that the common ancestor of plants and animals, that was an unicellular organism, should already present some features that announce the apparition of a neural system. Some authors (Meyerowitz, 2000) defend the idea that some neuronal rudiments could exist in elongated cells with a great membrane surface.

“phloem is an electrical conductor of bioelectrochemical impulses over long distances . . . structures of phloem and axon can be pictured as hollow tubes filled with electrolyte solutions” (Volkov, 2000)

“plants may be more sophisticated and share more in common with animals in their non-cognitive behaviours than previously thought” (Gersani et al., 2001)

The International Laboratory of Plant Neurobiology (LINV), in Florence, is the research group of F. Baluska and S. Mancuso, two prominent figures in plant neurobiology. A serie of publications are freely available on the website of LINV:


  • Peter W. Barlow (2008) Reflections on ‘plant neurobiology’, BioSystems 92 pp. 132–147
  • Volkov, A.G. (2000) Green plants: electrochemical interfaces, J. Electroanal. Chem. 483, pp. 150–156.
  • Gersani, M., Brown, J.S., O’Brien, E.E., Maina, G.M., Abramsky, Z. (2001) Tragedy of the commons as a result of root competition, J. Ecol. 89, pp. 660–669.

related: project groworld, category biology

  • plant_neurobiology.1313070822.txt.gz
  • Last modified: 2011-08-11 13:53
  • by lbilliet