Scientists find signs of intelligence in plants

Signs of intelligence found in plants
Photo credit: WAM

Goldenrod can perceive other plants nearby without ever touching them, by sensing far-red light ratios reflected off leaves, according to a research paper by a scientist in Cornell University, WAM reports. 

When goldenrod is eaten by herbivores, it adapts its response based on whether or not another plant is nearby. Is this kind of flexible, real-time, adaptive response a sign of intelligence in plants?

The question is not easy to answer, but Andre Kessler, a chemical ecologist, makes an argument for plant intelligence in a recent paper in the journal Plant Signaling and Behavior.

"There are more than 70 definitions that are published for intelligence and there is no agreement on what it is, even within a given field," said Kessler, professor in the Department of Ecology and Evolutionary Biology in the College of Agriculture and Life Sciences.

Many people believe that intelligence requires a central nervous system, with electrical signals acting as the medium for processing information. Some plant biologists equate plant vascular systems with central nervous systems and propose that some kind of centralized entity in the plant allows them to process information and respond. But Kessler firmly disagrees with that idea.

To make their argument for plant intelligence, Kessler and co-author Michael Mueller, a doctoral student in his lab, narrowed their definition down to the most basic elements: "The ability to solve problems, based on the information that you get from the environment, toward a particular goal," Kessler said.
As a case study, Kessler points to his earlier research investigating goldenrod and its responses when eaten by pests. When leaf beetle larvae eat goldenrod leaves, the plant emits a chemical that informs the insect that the plant is damaged and is a poor source of food.

Applying the concept of intelligence to plants can inspire fresh hypotheses about the mechanisms and functions of plant chemical communication, while also shifting people's thinking about what intelligence really means, Kessler said.

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