Do Plants Think? Some Scientists Say They Can

Botanical Discoveries Challenge Our Notions of Intelligence

While people generally understand that some animals are intelligent—defining intelligence as possessing “the capacity to solve problems”—it is not generally known that plants are as well. In 1880, Charles Darwin wrote The Power of Movement in Plants, in which he discussed how plants demonstrate intelligence through movement. Until recently, the book was largely ignored and the idea of plant intelligence dismissed. However Stefano Mancuso, and Italian botanist and professor at the University of Florence, recently set out to show that plants should be seen as more than food for wildlife or decoration.

In 2005, Mancuso established the Society for Plant Neurobiology with a group of international scientists. Critics argued that because plants don’t have brains or neurons, “plant neurobiology” is inaccurate. At a TED talk in 2010, Mancuso explained why he believes the name is valid. While plants may not have neurons, they possess electrical signals known as action potentials, which are similar to those found in human neurons. These action potentials are located in a plant’s root tips, a place logical for plants since they are widely spread rather than in a centralized brain. Plants’ sessile (rooted) nature prevents them from being able to run away or hide from predators that could easily bite or claw off a centralized brain.

Plants also demonstrate different forms of awareness. Although plants do not see images like humans do, they have photoreceptors that can perceive wavelengths of light such as infrared and ultraviolet. Studies show that plants use math to ration their “food supply” through the night. Plants determine how much starch, or “food” made by photosynthesizing sunlight, they have reserved, and then they divide it by the estimated time left before the sun rises. Plants can also plan their growth based on past and current weather conditions, monitor environmental variables with their roots, and differentiate between “self” and “other.”

Some scientists believe that when plants release ethylene, a hormone used as an anesthetic for humans, after they’re harmed, they may be using it for the same pain-relieving effect we do. This raises a challenging question: is it ethical to do things like mow the lawn or cut flowers for bouquets? Many plants use defense mechanisms, like a cactus’ spikes. Some even used them to obtain extra vitamins, such as a carnivorous plant that devours insects.

Another way plants demonstrate intelligence is through non-verbal communication. For example plants release fragrances for pollinators that indicate they are in need of pollination. They also show altruistic communication by using root systems to share resources with neighboring plants. Studies even indicate that plants are more likely to share with their relatives rather than plants of a different species.

All of these examples demonstrate plant intelligence. Next time you go for a walk in the woods or a stroll in the park, take some time to consider that you’re not alone. All around you plants are calculating and communicating, using “brains” as useful to them as ours our to us.

[Source: National Wildlife]