Understanding Plant Communication: From Historical Perspectives to Recent Discoveries

Background of Plant Communication

Throughout history, plants were often perceived as passive entities. However, recent studies have illuminated their sophisticated communication methods. The latest advancements in plant biology highlight diverse modes of communication, encompassing mechanical, chemical, and electrical signaling in the environment.

Early observations

Plants bear cultural and spiritual significance, with an ancient belief attributing life-like qualities to them. Researchers such as Charles Darwin in his work on plant tropisms noted observations that plants can respond and sense.

An Indian scientist Jagadish Bose used a crescograph in his work to show that plants can respond to various stimuli. This was known to be a controversial study, however later it was seen as a groundwork for the concept of plant communication mechanisms.

In the late 20^th century, researchers began exploring phenomena such as plant electrophysiology, root communication, plant-insect communication, and inter-plant communication.

How do plants communicate?

Some crucial phenomena of plant communication involve:

Sound: Plants often produce sounds in situations of stress which can be detected by mammals such as mice and bats. These sounds are typically ultrasonic and can be used to pass distress signals and airborne messages.
Chemical signalling: Plants release Volatile Organic compounds (VOCs) as chemical signals to alert others about potential threats such as environmental stress or predators.
Electrical impulses: The complex root network of plants has the ability to transmit electrical impulses, and coordinate the same to the environment.

A Recent Japanese Study…

A recent Japanese study led by Masatsugu Toyota a molecular biologist from Saitama University captured real-time footage of plants communicating. The team observed how an undamaged plant responded to volatile organic compounds (VOCs) released by damaged plants.

Plants use the fine mist of airborne compounds that surround them for communication. These substances alert nearby plants to potential danger. The video illustrates how plants react to these aerial alarms and how they receive them

The authors in the study said “Plants perceive VOCs released by mechanically or herbivore-damaged neighboring plants and induce various defense responses. Such interplant communication protects plants from environmental threats”

The setup of the study

In this study, researchers employed a setup comprising two boxes. One box housed the common mustard weed Arabidopsis thaliana, while the other contained a container with leaves and caterpillars, connected to an air pump. The reactions of a second, intact Arabidopsis plant, devoid of insects, were recorded in response to danger cues. Caterpillars were allowed to feed on chopped leaves from tomato plants and Arabidopsis thaliana. A biosensor, capable of detecting calcium ions and emitting a green glow, was incorporated into the experiment.

Conclusion

The video illustrates how undamaged plants sense signals from injured neighbors, responding with bursts of calcium signaling across their leaves. Mr. Toyota expressed, “We have finally unveiled the intricate story of when, where, and how plants respond to airborne ‘warning messages’ from their threatened neighbors.”

Upon analysis, researchers discovered that the airborne compounds Z-3-HAL and E-2-HAL, as triggers for calcium signals in Arabidopsis.