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

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.

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.

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.