Plants communicate — they are actually quite loquacious communicators. They are able to distinguish kin and non-kin. They communicate with plants of their own and other species and they communicate with animals and humans.
We are here in Iceland teaching a permaculture course with Robyn Francis and she likes to say plants are just upside-down humans. We have our senses up at the top — in our mouths, noses, ears and fingertips. Plants keep those mostly down in their roots but they also smell and taste and touch like we do. We keep our sex organs hidden down in our bottoms, but plants put them up on full display at the top.
But can a plant be intelligent? Some plant scientists, like Stefano Mancuso, think they are — since they can discover, learn, remember, and even react in ways we would call intelligent.
Michael Pollan, author of such books as Cooked, The Omnivore's Dilemma and The Botany of Desire, wrote a New Yorker piece a couple years ago revisiting The Secret Life of Plants by Peter Tompkins and Christopher Bird (1973) with a review of the latest developments in plant science. He said that for the longest time, even mentioning the idea that plants could be intelligent was a quick way to being labeled a whacko. But science has silenced the critics.
The new research causes a problem because it is often called plant neurobiology and plants do not use a central nervous system or have brains.
Nonetheless, it appears that plants can sense the presence of water or feel an obstruction in the path of its roots, before coming into contact with moisture or the obstruction. Plant roots shift direction to migrate towards the water source or to avoid the obstacle. If you've tried to cage bamboo perhaps you've encountered this.
Plants may be able to teach humans a thing or two, such as how to process information without a central processor like a brain.
Do plants use quantum mechanics, or can we speak of something called “quantum biology?” Jameel Sadik "Jim" Al-Khalili is an Iraqi-born British theoretical physicist, author and broadcaster. He is currently Professor of Theoretical Physics and Chair in the Public Engagement in Science at the University of Surrey. His recent TED talks provide an overview of some of the processes we are just learning about, including quantum tunneling in photosynthesis and DNA replication.
In a longer talk to the Royal Institution in 2013, Professor Khalili explored how quantum theory might explain some of the mysteries of plant senses.
In a forest system, Robyn tells our class, mother trees nurture young seedlings by sending them water and nutrients. They also starve out and steal nutrients from emerging plants they consider hostile to the ecology they are cultivating. In South Africa acacia trees increased the tannin in their leaves by 400% to poison the soil in order to halt an invasion by kudzu.
Plants may have as many as 15 senses, not just the six we take for granted. They can hear pollen. They can taste poisons at minute thresholds. They can feel the coming weather. They can smell danger. Photoreceptors in leaves sense and respond to changes in light, wind and humidity. Cryptochromes set circadian rhythms and control photomorphogenesis in response to blue or ultraviolet light. We know that salmon, sea turtles, spotted newts, lobsters, honeybees, and fruit flies can all perceive and utilize geomagnetic fields. Lately we’ve learned some plants (e.g.: Arabidopsis thaliana) also have magnetic compasses coming from a radical pair mechanism within the protein of their cryptochromes.
The entanglement of life is beyond an observable physical effect. We may not understand it yet, but with quantum mechanics, we are beginning to be able to name some of what we observe of the mystery.