Neurobiological View of Plants and Their Body Plan - Communication in Plants: Neuronal Aspects of Plant Life - page 20

2.1
Introduction
It was Aristotle and his students who made the first philosophical attempts
to understand plants in their complexity. At this ancient time, the main
interest for plants was limited to their usefulness in medicine. Much later,
in the sixteenth century, the first attempts were made to understand the
basic principles of structure and function of plants. At first, these studies
were largely devoted to plant distribution, taxonomy, and morphology.
Later, because of the technological advances resulting in the invention of
the microscope and inspired by the earlier work on medicine, anatomy and
cytology were added to the plant sciences curriculum. In fact, the cellular
nature of animals and plants was elaborated first in plants (Hooke 1665,
reviewed by Baluška et al. 2004a).
By the end of nineteenth century, it was realized that plants were even
more similar to animals than had been thought hitherto. In fact, Huxley
(1853) went so far as to say that “The plant is, then, an animal confined in
a wooden case...”. Advances in physiology helped confirm this, especially
with regard to some of the basic physiological processes, such as respira-
tion, digestion, and cell growth, where plants often provided the material
of choice for experimental studies. In such circumstances, plant physiology
wasborn;anditnowdominatesworkintheplantsciences.Furthermore,
a big surprise is that plants have been shown to be identical to animals from
several rather unexpected perspectives. For their reproduction, plants use
identical sexual processes based on the fusion between sperm cells and
oocytes (Smyth 2005). Next, plants attacked by pathogens develop im-
munity using the same processes and mechanisms that operate in animals
(Nürnberger et al. 2004). Last, but not least, animals and plants use the same
molecules and pathways to drive their circadian rhythms (Cashmore 2003).
Currently, plant science has reached another crossroad. A critical mass of
new data has been accumulated which has culminated in the establishment
of plant neurobiology as the most recent discipline of plant sciences.
Traditionally, plants are considered to be passive creatures mostly be-
cause, relative to the perception of man, they hardly move and make no
noise. However, recent advances in plant sciences clearly reveal that plants
are “intelligent” organisms capable of learning and taking decisions in re-
lation to their environmental situation (Trewavas 2001, 2003). Plants are
not just passive victims of circumstance but, rather, are active organisms
which can identify their herbivores and actively recruit enemies of these
herbivorous predators (Dicke and Sabelis 1988; van der Putten et al. 2001).
For instance, maize roots attacked by larvae of Diabrotica beetle induce
volatile compounds which recruit entomopathogenic nematodes which in
turn kill this rootworm (Rasman et al. 2005). Moreover, plants use a battery