Dear EarthTalk:

Is it true that plants communicate by sending chemical signals through the air?

Melissa Hart, via email

Recent research reveals that plants, despite lacking brains or nervous systems, possess a surprising ability to “talk” via chemical signals. This fascinating discovery sheds light on a hidden world of plant communication with profound implications for agriculture, ecology and climate resilience. Plants communicate mainly through volatile organic compounds (VOCs)—chemical signals they release into the air—which serve as a sophisticated alarm system, warning other plants about potential threats like herbivores, pathogens or environmental stressors. When a plant detects an attack, it can alert other plants, enabling them to ready defensive chemicals or close their stomata to conserve water and nutrients.

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According to National Geographic, this signaling system operates like an “early warning network,” letting plants prepare themselves and the surrounding community for incoming dangers. This highlights the intricate interdependence within plant ecosystems. One well-documented example involves tomato plants. When attacked by pests, tomato plants release VOCs that signal neighboring plants to ramp up their production of defensive chemicals, effectively creating a shared defense strategy. This phenomenon isn't limited to a single plant species—"eavesdropping" plants in the vicinity can also benefit from these warnings, adapting their defenses even if they aren’t directly under attack. In addition to defensive strategies, plants use VOCs for environmental adaptation. Certain plants release VOCs to attract the predators of their attackers. A classic example is caterpillar-infested plants emitting signals to draw in parasitic wasps, which lay eggs in the caterpillars and effectively neutralize the threat.

Understanding plant communication could revolutionize agriculture. Farmers could enhance crop resistance to pests and reduce reliance on chemical pesticides. This would contribute to ecological balance by preserving biodiversity and reducing environmental impact. Moreover, plant communication plays a crucial role in maintaining ecosystem health. As Wired notes, this “language of chemical signals” isn’t just about individual survival—it’s about fostering community resilience in the face of challenges.

Plant communication does have skeptics. Some scientists believe it is simply a passive chemical response and not “communication.” Nonetheless, the discovery of chemical signaling in plants highlights the complexity and interconnectedness of ecosystems. As SciTechDaily notes, understanding these signals could revolutionize how we protect crops and manage natural ecosystems. By unraveling the secrets of plant communication, we gain not only insights into the hidden lives of plants but also tools to build a more sustainable and resilient future.

CONTACTS

• Plants can talk. Yes, really. Here’s how, https://www.nationalgeographic.com/science/article/plants-can-talk-yes-really-heres-how.

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