Plants are generally considered to be passive and insensitive organisms. One can trace this strong belief back to Aristoteles, who positioned immobile plants outside of the sensitive life domain. The millennia that have elapsed between time of Aristoteles and the present day highlight the fact that it will very difficult to change this almost dogmatic view. For instance, one of the first serious attempts to rehabilitate plants was performed by no less than Charles Darwin, in 1880. At the end of the book The Power of Movement in Plants, which he wrote together with his son Francis, they proposed that the root apex represents the brain-like anterior pole of the plant body.
This volume, in fact the whole series, documents a paradigm shift that is currently underway in the plant sciences. In the last two or three decades, plants have been unmasked as being very sensitive organisms that monitor and integrate large numbers of abiotic and biotic parameters from their environment. That plants react to electric stimuli in the same manner as animals was shown by Alexander von Humboldt a few years after Luigi Galvani discovered the electrical stimulation of animal muscles in frogs’ legs. Later, when animal action potentials were discovered in animals, similar action potentials were soon recorded in plants too. Initially only “sensitive plants” were tested, but some 30 years ago it was found that all plants use action potentials to respond to environmental stimuli. This rather dramatic breakthrough went almost unnoticed in the mainstream plant sciences. Only recently, the emergence of plant neurobiology has highlighted this neglected aspect of biology. The obvious conservation that occurs throughout evolution means that action potentials provide both plants and animals with evolutionary advantages that are crucial to their adaptive behavior and survival. As plants evolved action potentials independently of animals, this phenomenon also holds the key to illuminating the mystery of convergent evolution, a phenomenon that does not conform to the classical Darwinian principles of biological evolution.
Sample chapter from the book:
Cognition in plants:
We discuss the possibility and the meaning of the claim that plants are cognitive from the perspective of embodied cognition. In embodied cognition, the notion of cognition can be interpreted in a very broad way and applied to many free-moving creatures. In this chapter, we discuss whether and (if so) how this approach applies to intelligence in plants. Building on work from “plant neurobiology,” we discuss the differences in speed between plants and animals, similarities between sensory-driven plant growth and animal memory, and the presence of offline behavior in plants. In our view, these examples show that under a wide, embodied interpretation of cognition, plants may well qualify as being cognitive.