Do plants possess intelligence?
Although plants don't have a brain, they can still detect risks, formulate tactics, and protect themselves intentionally. But is this enough to classify plants as intelligent? A research team has now tackled this question, yielding unexpected findings.
Smart actions aren't confined to humans or certain animals but extend to various species as well. For example, dolphins can think abstractly, ravens use tools, and octopuses can even count. But how about plants? Research indicates that certain plants respond to environmental stimuli within their movement limitation. For instance, goldenrod can detect the presence of similar plants and deter herbivores. Is this evidence of plant intelligence?
This question is more intricate than initially believed. "Approximately 70 definitions of intelligence have been published; and even within a specific field, there's no consensus about what intelligence entails," states Ecologist André Kessler from Cornell University in a statement. Many animal intelligence definitions assume a central nervous system for information transmission through electrical signals. Some biologists hypothesize that in plants, this function might be substituted by their vascular system and chemical signals. Consequently, plants also possess a sort of command center that processes information and triggers responses.
There's evidence for these suppositions so far, but no definitive proof. "There's no clear evidence of similarity with a nervous system, although we can see electrical signals in plants," says Kessler. "Yet, the question is, how significant are these signals for a plant's ability to process environmental stimuli." According to Kessler's definition of intelligence, plants must react to environmental stimuli and address challenges strategically to be deemed intelligent.
Strategic Defense Mechanisms
The research duo led by Kessler and Michael Mueller investigated this, using goldenrod (Solidago altissima) as an illustration. They cited earlier studies on goldenrod's reaction to a pest infestation. It appears that the plant secretes a chemical substance when its leaves are consumed by leaf beetle larvae. This substance signals to the insect that the plant is damaged and an unfavorable food source. These volatile organic compounds (VOCs) in the air, referred to as odorants, are also detected by neighboring goldenrod plants and stimulate them to produce their own defensive compounds. This strategy helps goldenrods repel insects and minimize damage from herbivores.
In experiments, the researchers also showed that the goldenrod employs additional defense tactics. When eaten by beetles, its growth rates quicken – but only if there are other goldenrod plants nearby. Without conspecifics in the area, the growth rate remains unaltered, but the goldenrod then produces more chemical defense compounds. The plants identify the presence of neighboring plants based on the red spectrum light reflected by their leaves, according to the two biologists.
Kessler explains, "this would correspond to our definition of sunflower intelligence." Simplified by Kessler, "the sunflower's behavior changes depending on the information it receives from its surroundings. They can utilize environmental cues to predict future situations and respond accordingly."
The Whole Plant is the Brain
Kessler believes, "the sunflower's brain is the entire plant, without the need for central coordination." Instead of electrical signals, there's a chemical signaling system throughout the organism. Studies by other researchers have already established that each plant cell perceives a broad light spectrum and is equipped with sensory molecules, allowing them to recognize very specific volatile compounds from neighboring plants.
"They can perceive their environment very precisely; as far as we know, each individual cell does," says Kessler. The cells are specialized, but they all perceive the same things and communicate with each other chemically to coordinate actions related to growth or metabolism.
Interestingly, the researchers' findings could reignite the debate on what intelligence actually represents. They suggest that it should be clarified when and if Artificial Intelligence (AI) is comparable to animal or plant intelligence. "According to our definition, AI is not intelligent," claims Kessler. AI can recognize and analyze patterns in information currently, but it can't understand problems to attain goals with actual comprehension.
Read also:
Based on the text, here are two sentences containing the words 'Studies' and 'Botany':
- Studies in botany have shown that goldenrod plants can detect the presence of similar plants and produce defensive compounds to deter herbivores.
- Recent studies in plant behavior and botany suggest that goldenrod plants exhibit strategic defense mechanisms, such as increasing growth rates and producing more chemical defense compounds in the presence of neighboring plants.
