Introduction - Plants Have Feelings Too

We all learned about plants in science class when we were kids. Remember photosynthesis, the process used by plants to convert light energy, normally from the sun, into chemical energy that could be later released to fuel a plant’s activities. We also learned about how the 300,000 known plant species reproduce by spreading their pollen and seeds from beautiful flowers. I even remember that if you talk or sing to your plants, they grow faster. That’s pretty standard stuff. But did you know that plants communicate with each other and with insects; that they are much more sophisticated in sensing than animals; and that every single root apex is able to detect and monitor concurrently and continuously at least 15 different chemical and physical parameters. Did you know that plant cells are filled with the same microtubules found in human brain neurons? Did you know that plants have feelings too?

Aristotle wrote in “De Anima” that plants reside on the edge between living and not living, and have a kind of very low-level, vegetative, soul. Aristotle’s plant image, however, was bound by the huge evolutionary constriction of the “rootedness” that keeps plants immobile. Plants can’t escape a bad environment, and can’t migrate in search of food or a mate. Plants, therefore, have developed incredibly sensitive and complex mechanisms that guide their directional movements by changing cellular growth and elongation in response to their environment. Roots, for instance, stop developing downwards as they encounter a physical obstacle, and grow horizontally instead. Bean vines will grow and elongate, flipping from side to side, to lash onto a pole or structure. Michael Pollan, author of "The Omnivore's Dilemma" and "The Botany of Desire," explains. "Plants have ways of taking all the sensory data they gather in their everyday lives ... integrate it and then behave in an appropriate way in response. And they do this without brains, which, in a way, is what's incredible about it, because we automatically assume you need a brain to process information.”

Plants don’t have eyes, ears, or a nervous system; however, they communicate with other plants and animals in a variety of ways through behavior, body patterns, and chemistry. A classic example is the warm-climate Acacia and its tenants, ants that live in the hollowed-out thorns of the plant. The tree provides shelter, nectar and proteins for the ants. In return, the ants defend the tree with their lives from other insects, birds and small animals. Another fascinating example involves maze and caterpillars. When caterpillars start eating on a stalk of maze, the plant responds by releasing a chemical that attracts wasps that, in turn, attack the caterpillars. If you play a recording in a field of maze of the sounds caterpillars make when they are eating maze, the plant will release the wasp-attracting chemical as though the caterpillars are there. 

Garzon and Keijzer, in their paper “Plants: Adaptive Behavior, Root Brains and Minimal Cognition”, suggest that plants exhibit sophisticated forms of decision-making and self-acquaintance via what scientists have recently started calling the “Root Brain”: a control center for behavior that is dispersed across a plant’s root tips. Studies suggest that plants have a way of distinguishing their own roots from others of their same species as well as alien root structures. Plant roots compete for physical space, regardless of nutrient concentration, by means of toxic and non-toxic chemical and electric signaling that ward off alien roots and support their own kind. The major contributors in this information collection and self identification process appear to be microtubule functions and electrical gamma wave synchrony. These are the same processes and structures that are found in all animals.

There is considerable debate over whether plants are conscious. The analogies of thinking are very apparent. There is no doubt that plants behave as though they are aware of their environment. They communicate with each other and with animals. They hear, feel, and appear to be self aware and aware of others. What do you think ?