Plants do not talk, but they can communicate.
Plants' communication is chemical. For example, trees, flowers, and tomatoes release chemical compounds into the air. When released, these compounds warn other, neighboring plants about diseases so they can defend themselves. It remains a mystery, however, how these plants receive and react to these warnings.
A study released in the journal Proceedings of the National Academy of Sciences documented one experiment Japanese researchers conducted to examine plant communication. They identified one chemical message sent by tomato plants and studied it from its release to the results it caused. Specifically, they grew infested and healthy tomato plants in two plastic containers connected by a tube. The infested plant was placed upwind while the healthy plant was placed downwind. The downwind tomato plant was then exposed to the cutworm caterpillar, a species that spreads disease. Results from this study indicate that tomatoes near plants previously exposed to the disease are better able to defend themselves.
Hoping to find an effective pesticide to preserve plants, researchers also fed a compound called HexVic to the cutworm caterpillars. These caterpillars showed a 17 percent decrease in survival, in comparison to those that were not fed the compound. The researchers then sprayed HexVic gently on healthy tomato plants, allowing them to defend themselves more efficiently against the pesty caterpillars. This study suggests that these plants know to protect themselves because of the warnings they receive from their plant neighbors.
Researchers have yet to determine how many plants, like tomatoes, are capable of this friendly communication.
[Source: Time for Kids]