Plants eat light, grow almost everywhere on Earth, and make up 99% of the planet’s biomass. But do what extent do plants think? Or feel? Michael Pollan tackles the question of plant intelligence in a thought-provoking article for the New Yorker (sadly behind their paywall).
Indeed, many of the most impressive capabilities of plants can be traced to their unique existential predicament as beings rooted to the ground and therefore unable to pick up and move when they need something or when conditions turn unfavorable. The “sessile life style” as plant biologists term it, calls for an extensive and nuanced understanding of one’s immediate environment, since the plant has to find everything it needs, and has to defend itself, while remaining fixed in place. A highly developed sensory apparatus is required to locate food and identify threats. Plants have evolved between fifteen and twenty different senses, including analogues of our five: smell and taste (they sense and respond to chemicals in the air or on their bodies); sight (they react differently to various wavelengths of light as well as to shadow); touch (a vine or root “knows” when it encounters a solid object); and, it has been discovered, sound.
In a recent experiment, Heidi Appel, a chemical ecologist at the University of Missouri, found that, when she played a recording of a caterpillar chomping a leaf for a plant that hadn’t been touched, the sound primed the the plant’s genetic machinery to produce defense chemicals. Another experiment, dome in Mancuso’s lab and not yet published, found that plant roots would seek out a buried pipe through which water was flowing even if the exterior of the pipe was dry, which suggested that plants somehow “hear” the sound of flowing water.
One of the researchers featured in the article, Stefano Mancuso, has a TED talk available in which he outlines his case for plant intelligence:
The article also discusses if plants have feelings. If so, should we feel bad that our wifi routers might kill plants?
Update: Mancuso and Alessandra Viola have collaborated on a new book about the intelligence of plants, Brilliant Green: The Surprising History and Science of Plant Intelligence.