Neurobiological View of Plants and Their Body Plan - Communication in Plants: Neuronal Aspects of Plant Life - page 19

2 Neurobiological View of Plants

and Their Body Plan

František Baluška, Dieter Volkmann, Andrej Hlavacka,
Stefano Mancuso, Peter W. Barlow

Abstract All principal metabolic biochemical pathways are conserved in animal and plant
cells. Besides this, plants have been shown to be identical to animals from several other rather
unexpected perspectives. For their reproduction, plants use identical sexual processes based
on fusing sperm cells and oocytes. Next, plants attacked by pathogens develop immunity
using processes and mechanisms corresponding to those operating in animals. Last, but not
least, both animals and plants use the same molecules and pathways to drive their circadian
rhythms. Currently, owing to the critical mass of new data which has accumulated, plant
science has reached a crossroads culminating in the emergence of plant neurobiology as
the most recent area of plant sciences. Plants perform complex information processing
and use not only action potentials but also synaptic modes of cell-cell communication.
Thus, the term 'plant neurobiology' appears to be justified. In fact, the word neuron was
taken by animal neurobiologists from Greek, where the original meaning of this word is
'vegetal fibre'. Several surprises emerge when applying a 'neurobiological' perspective to
illustrate how the plant tissues and the plant body are organized. Firstly, root apices are
specialized not only for the uptake of nutrients but they also seem to support neuronal-like
activities based on plant synapses. These synapses transport auxin via synaptic processes,
suggesting that auxin is a plant-specific neurotransmitter. Altogether, root apices emerge
as command centres and represent the anterior pole of the plant body. In accordance with
this perspective, shoot apices act as the posterior pole. They are specialized for sexual
reproduction and the excretion of metabolic products via hydathodes, trichomes, and
stomata. Next, vascular elements allow the rapid spread of hydraulic signals and classical
action potentials resembling nerves. As plants are capable of learning and they take decisions
about their future activities according to the actual environmental conditions, it is obvious
that they possess a complex apparatus for the storage and processing of information.

Life has always seemed to me like a plant that lives on its rhizome. Its true life is
invisible,hiddenintherhizome.Thepartthatappearsabovegroundlastsonlyasingle
summer. Then it withers away - an ephemeral apparition. When we think of the
unending growth and decay of life and civilisations, we cannot escape the impression
of absolute nullity. Yet I have never lost a sense of something that lives and endures
underneath the eternal flux. What we see is the blossom, which passes. The rhizome
remains.
Carl Gustav Jung: Memories, dreams, reflections , Collins and Routlege & Kegan Paul,
London, 1963. Translated from German into English by Richard and Clare Winston.