They discover how plants communicate when faced with stress.

▲ Our framework provides a mechanistic understanding of what drives signals from one place to another and explains how mechanical and chemical signals propagate , explained scientist Vesna Bacheva. Photo: Cornell University

Europa Press

La Jornada Newspaper, Tuesday, April 29, 2025, p. 6

Madrid. A new study, published in the Proceedings of the National Academy of Sciences , has solved a centuries-old mystery about how plants internally signal stress.

By understanding how plants' communication systems work, the team could exploit those signals to create plants that can communicate with people and each other, and that are programmed to respond to specific stressors.

The solution lies in the negative pressure that exists within a plant's vasculature, which is necessary to retain water within its stems, roots, and leaves when it is dry. Stressors alter the pressure balance within the plant, which in turn generates movement in the plant fluid, which can carry mechanical and chemical signals throughout the plant to counteract a stressor and restore balance.

“We’re trying to build fundamental knowledge to understand how communication happens in plants ,” said first author Vesna Bacheva, a postdoctoral associate at Cornell University’s Cropps (Center for Research on Programmable Plant Systems) in a statement. “Our framework provides a mechanistic understanding of what drives signals from one place to another and explains how mechanical and chemical signals propagate.”

"This is a very important advance in an area that is surprisingly nascent in terms of true mechanistic understanding ," said Abraham D. Stroock, one of the study's collaborators.

More than a century ago, scientists began to question how plants might transmit signals from one part to another to generate a response to stressors. Some scientists hypothesized that plants might use hormones or chemicals to communicate, while others suggested they used mechanical signals.

Changes in pressure

Bacheva and colleagues have developed a predictive model and a unified framework that explains how mechanical and chemical signals are transmitted through plants when stressors cause changes in pressure.

The vascular system of plants is made up of a system of tubes subjected to pressure, which they exert on elastic tissues. When a plant suffers a wound, such as when a caterpillar bites a leaf, a pressure change occurs that can trigger subsequent coupled responses.

Researchers suggest that pressure changes can trigger a massive influx of water through the plant, transporting chemicals released by cells at the wound site to the rest of the plant. One hypothesis is that these chemicals could trigger the production of a toxic acid that repels insects. Pressure changes could also cause the opening of mechanosensitive channels located around the vasculature and the release of calcium or other ions with downstream effects. A calcium influx could then induce the expression of genes that are part of a defensive response.

We're trying to develop plants that tell us what they're experiencing at that moment , Bacheva explained. These include pigmented plants that change color or fluorescent plants that light up when they need water. The ultimate goal is to achieve two-way communication, so that an indicator plant can not only communicate that it needs water, but a farmer can also inform a plant that it could be dry for many days and that it should use the liquid more efficiently.