We humans have the tendency to think that intelligence needs a brain. We find it difficult to view a living thing that can’t run away, that we can’t hear or see communicating and that we can easily cut chunks off without it dying, as something that is ‘intelligent’. Plants just are, and they grow. But do they communicate? And learn? And, if this is the case, what use is that to us?

The science of plant neurobiology is still young

Investigating the communication and intelligence of plants is still a fairly young science. Until two decades ago we were so little interested in how plants actually live, we didn’t want to know anything about it. In fact, a best-selling book was to blame for this lack of interest.

In 1973 Peter Tompkins and Christopher Bird released ‘The Secret Life of Plants’. This book, stating that plants are intelligent and even respond to us, was received to wide acclaim, in the closing years of the flower-power era. But in the scientific arena it was classified as nonsense, because large parts of their research could not be replicated and did not meet scientific requirements. Because of this popular book, later studies into plant communication and intelligence were not taken seriously and thus avoided for years.

Resistance ran deeply. When six major scientists published a manifesto in 2006, stating plant neurobiology was indeed a science, it got a sceptical reception. Yet they persisted. According to the group there were more than enough clues that plant behaviour was more complex and intelligent than mere scent, chemical substances and predestination through genetics. These scientists, who include Eric D. Brenner, a molecular biologist from America, Stefano Mancuso, an Italian plant physiologist, František Baluška, a cell biologist from Slovenia, and Elizabeth Van Volkenburgh, an American biologist, all did legitimate research that could be reproduced and used very careful terminology. Still, they demonstrated that the electrical and chemical signalling systems in plants are very complex and even comparable to those used by animals. And the way their hormones work, too, didn’t appear too differ much.

In the following video, Professor Stefano Mancuso, one of the leaders of the scientists working in plant neurobiology, tells about the intelligence of plants and our ambivalence toward plant life.

A complex chemical vocabulary from another kingdom

Around the same time, in 2006, for the first time science was also able to quickly analyse complete sets of genes. Of course the animal kingdom was turned to first, and it was soon concluded that man has the most complex and largest set of genes. This confirmed that man is at the top of the chain. That is, until they started analysing plants. Then we discovered that common plants, like rice, have 50,000 genes while we humans ‘only’ have 26,000.

But this doesn’t necessarily contradict the statement that the further a living creature is evolved, the more complex its gene structure. The kingdom of plants is many eons older than the animal kingdom, and has continued to develop since. And this was by no means a less complex form of evolution. But structurally different? Yes. We humans have five senses. Plants, being more dependent of their environment, have many more. Plants can see, hear and smell, but they can also detect chemical compounds, electricity and gravity and, using these senses, can communicate across large distances.

Meanwhile, the study of the chemistry of plants and its role in the survival of the organism continued. It appeared that the average plant has a vocabulary of about 3,000 chemical compounds. This vocabulary can be used for communicating with neighbours, friends, enemies, and pollinators but also as a defence mechanism. It is indeed a complex and highly intelligent system.

An interesting study by Professor Gagliano, for instance, has shown that plants can learn and they can retain this knowledge for weeks. In addition, research into the tips of the roots delivers very interesting findings. It seems they function similar to our nerve cells and at the same time contain the most fascinating newly discovered senses.

Now what’s the use of all this knowledge?

With an open mind, listening and looking carefully, we will always learn more from newly acquired knowledge than if we approach this with resistance. That intelligence needs a brain is just an assumption. A swarm of birds or a colony of ants also show signs of intelligence. This means that a new definition of intelligence as: the ability to adequately respond to challenges presented by the environment and circumstance could be more meaningful.

And it can be of great use to us too. A lot of the knowledge about the way plants warn each other and excrete antibodies, is already used in the combat against plant diseases and pests. And this kind of knowledge could tell us when is the best moment to harvest, or teach us which plants can help or repel each other. Currently, experiments are carried out which electrical signals in order to make plants move their leaves or even have them generate electricity. Who can tell; our potted plant might become our potted lamp in the future, or a working part of our house robot. The ways in which roots and soil organisms collaborate teaches us how we can manage our forests smarter, but also how to build better networks than our current Internet, for example. But most of all, science has discovered that there is so much more to discover. We know that plants communicate with chemical compounds and electricity, but we don’t speak the languages yet. But just imagine the possibilities of being able to understand what plants say, one day.

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