 complex animals, but not in simple ones. Different parts of the plant communicate with each other, exchanging information on cellular, physiological and environmental states.
For example root growth is dependent on a hormonal signal thatâs generated in the tips of shoots and transported to the growing roots, while shoot development is partially dependent on a signal thatâs generated in the roots. Leaves send signals to the tip of the shoot telling them to start making flowers. In this way, if you really want to do some major hand waving, the entire plant is analogous to the brain.
But while plants donât have neurons, plants both produce and are affected by neuroactive chemicals! For example, the glutamate receptor is a neuroreceptor in the human brain necessary for memory formation and learning. While plants donât have neurons, they do have glutamate receptors and whatâs fascinating is that the same drugs that inhibit the human glutamate receptor also affect plants.
From studying these proteins in plants, scientists have learned how glutamate receptors mediate communication from cell to cell. So maybe the question should be posed to a neurobiologist if there could be a botany of humans, minus the flowers!
Darwin, one of the great plant researchers, proposed what has become known as the “root-brainâ hypothesis. Darwin proposed that the tip of the root, the part that we call the meristem, acts like the brain does in lower animals, receiving sensory input and directing movement. Several modern-day research groups are following up on this line of research.