Monica Gagliano, an evolutionary ecologist who challenges traditional views on plant intelligence, joins home inspector Alvin Ubell to discuss the surprising capabilities of plants. They explore how plants may sense their environment and even exhibit memory, using fascinating examples like the mimosa pudica's defensive reflexes. Ubell reveals the intricate ways plant roots interface with infrastructure, highlighting a plant's instinctual behavior in seeking water. Together, they encourage a rethinking of what constitutes intelligence in the natural world.
Plants exhibit remarkable abilities to sense moisture and sounds, suggesting they possess more sophisticated response systems than previously believed.
Experiments reveal that plants can learn and remember experiences over time, challenging the traditional understanding of cognition and memory exclusive to animals.
Deep dives
Tree Roots and Water Pipes
Tree roots often exhibit an uncanny ability to find and wrap around underground water pipes, potentially leading to damage. The hosts discuss observations made by plumbing inspectors who frequently discover this phenomenon, noting how roots can infiltrate pipes even when the tree is located many yards away. A specific example shared illustrates how a magnolia tree's roots found their way into a household sewer line, highlighting the fragility of plumbing systems against nature's encroachment. This behavior raises intriguing questions about how plants seem to have an awareness of their surroundings and the resources they need.
Plant Sensitivity to Water and Sound
In a series of experiments, a plant biologist investigates how plants can detect water sources through their roots. A notable experiment involved placing plants in a specially designed pot that restricted their root growth toward a water pipe, yet the majority of roots consistently grew toward the pipe, indicating a heightened sensitivity to moisture. Another experiment replaced the water pressure with the sound of water, and plants demonstrated a preference for the sound, suggesting they can respond to auditory cues. These findings challenge traditional views on plant behavior, hinting that plants possess more sophisticated response mechanisms than previously understood.
Learning and Memory in Plants
The discussion then shifts towards the concept of learning in plants, as researchers explored whether plants could retain information from experiences. An experiment with mimosa pudica plants demonstrated that after repeated drops, the plants stopped folding their leaves, suggesting they learned from the repeated non-threatening experience. Further tests showed that these plants could remember the lesson for an extended period, even after weeks, showing remarkable retention of knowledge. This points toward a complex understanding of plant behavior and raises questions about their cognitive abilities, challenging the notion that memory is exclusive to animals with brains.
Conditioning Plants Like Pavlov's Dogs
In another intriguing experiment, researchers explore whether plants could be conditioned similar to Pavlov's dogs, which learned to associate a bell with food. By using a fan as a neutral stimulus and a light as a food source, the experiment aimed to see if plants could anticipate light when only exposed to the fan. The results showed that the pea plants leaned towards the fan even when no light was present, demonstrating an ability to form associations. This landmark study not only emphasizes the intelligence of plants but also opens avenues of inquiry into the underlying mechanisms by which they store and retrieve information, pushing the boundaries of our understanding of plant biology.
In an episode we first aired in 2018, we asked the question, do you really need a brain to sense the world around you? To remember? Or even learn? Well, it depends on who you ask. Jad and Robert, they are split on this one. Today, Robert drags Jad along on a parade for the surprising feats of brainless plants. Along with a home-inspection duo, a science writer, and some enterprising scientists at Princeton University, we dig into the work of evolutionary ecologist Monica Gagliano, who turns our brain-centered worldview on its head through a series of clever experiments that show plants doing things we never would've imagined. Can Robert get Jad to join the march?
We have some exciting news! In the “Zoozve” episode, Radiolab named one of Venus's quasi-moons. Then, Radiolab teamed up with The International Astronomical Union to launch a global naming contest for one of Earth’s quasi-moons, so that you, our listeners, could help us name another, and we now have a winner!! Early next week, head over to https://radiolab.org/moon, to check out the new name for the heavenly body you all helped make happen.
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Leadership support for Radiolab’s science programming is provided by the Gordon and Betty Moore Foundation, Science Sandbox, a Simons Foundation Initiative, and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.
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