WWW.GREENMATTERS.COM / SUSTAINABLE LIVING

Scientists Just Found Out Plants ‘Talk’ to Each Other — Especially About Their Natural Enemies

The team mainly explored the behavior of a plant called 'Arabidopsis thaliana' when it was exposed to a pest attack.

PUBLISHED 7 HOURS AGO

Biologist examining the condition of the forest and the trees. (Representative Cover Image Source: Getty Images | Daniel Balakov)

Beyond the naked eye of humans, plants live in a fascinating world of fantasy. Unfathomable to human imagination, plants usually remain surrounded by a fine mist of airborne compounds that hang in the air. Whenever an insect or an animal attacks a plant, the injured plant silently alerts its fellow plants to activate their defense mechanism. A team of Japanese researchers recently explored this phenomenon of plant chattering and published some noteworthy findings in the journal Nature Communications, with a YouTube video.

Science Arabidopsis plant Arabidopsis thaliana genetic research research (Representative Image Source: Getty Images | Pans Laos)

Silent conversations between plants

Female scientist or tech picks a cress plant from a test jar for analysis with tweezers. (Representative Image Source: Getty Images | Anyaivanova)

Like other living organisms, plants also communicate with each other. Scientists first found the evidence of this “interplant signaling” during the 1980s. They examined more than 30 plants, including Sitka willow, poplar trees, lima bean, tobacco, tomato, and sagebrush, and reported that these plants “exhibited increased anti-herbivore properties when grown near damaged plants.” In the latest research, the team confirmed that plants talk to each other via a process called “calcium signaling.” A research team led by Yuri Aratani and Takuya Uemura, molecular biologists at Japan's Saitama University, revealed that each time a plant detects “volatile organic compounds” (VOCs) in the air, it sends out SOS signals to its neighbour.

The chemistry behind it

VOCs are organic or carbon-containing compounds with a high vapor pressure, which means they evaporate quickly into the air. These chemicals are found in a multitude of everyday use substances like adhesives, cleaning chemicals, and even in some food products. As a result, plants are enshrouded by a mizzle of VOCs.

Cluster of the aquatic plant watergress (Representative Image Source: Unsplash | Nebular)

Apart from the VOCs released by miscellaneous things, plants also emit these chemicals sometimes, when they sense danger. When an insect or parasite attacks a plant, or when an animal or human rips it from the soil, a defense mechanism is activated in the frightened plant’s body. This protective mechanism doesn’t just repel other herbivores but also ejects invisible plumes of VOCs, including green leaf volatiles (GLVs), terpenoids, and amino acid derivatives, in response to wounding and injury.

Interplant interaction

Also known as “plant to plant communication” or “plant eavesdropping,” the release of VOCs prompts a cycle of communication in which plants send volatile cues to their friends, alerting them of the threat lurking around. These volatile molecules are the same ones responsible for the smell of freshly cut grass, which is basically a hint of grasses screaming as they are being plucked and forced to die.

Weeding garden beds with growing green parsley and removing weeds with hands close-up. (Representative Image Source: Getty Images | Komar)

Unlike animals, plants don’t have a nose. But they have something called “guard cells.” These tiny, bean-shaped cells embedded on surfaces consist of small pores that open and close at the rhythms of plants' breath. When a plant emits VOCs, these pores in the neighboring plants sense the compounds, and the defenses are activated.

Communication in Arabidopsis

Thale cress (Arabidopsis thaliana) stem epidermis with hairs, and stomata. Scanning electron microscopy. (Representative Image Source: Getty Images | Heiti Paves)

Researchers used a real-time field imaging method to visualize and examine Arabidopsis thaliana. According to ScienceDirect, it is a model flowering plant belonging to the mustard family, also known by names like “thale cress,” “wild mustard weed,” and “mouse ear cress.” The team employed a green fluorescent protein-based calcium biosensor and a wide-field real-time fluorescence microscope to observe changes in the plant in real-time. They released an army of caterpillars upon the leaves of this plant and rigged up a pump to transfer the emitted compounds to uninjured neighbours.

What researchers found?

Arabidopsis thaliana, the thale cress, mouse-ear cress or arabidopsis, is a small plant from the mustard family (Brassicaceae) (Representative Image Source: Getty Images | Chitro Stock)

Researchers observed a rapid increase in the calcium concentration of Arabidopsis, followed by exposure to the VOCs emitted by injured plants. “These volatiles trigger the expression of biotic and abiotic stress-responsive genes in a calcium-dependent manner,” they wrote in the study. “These results suggest that VOCs emitted by damaged Arabidopsis caused calcium changes in neighboring intact Arabidopsis plants.” "We have finally unveiled the intricate story of when, where, and how plants respond to airborne 'warning messages' from their threatened neighbors," Masatsugu Toyota, a molecular biologist at Saitama University in Japan and study author, said in a press release.