Communication Among Plants

    You might not think of plants as particularly chatty but in reality, they communicate surprisingly well with each other, especially when faced with danger. According to a recent study in the journal Frontiers in Plant Science injured plants send out emergency signals to alert neighbors to start building up their defenses.

    The chain of events that led to this surprising discovery began about two years ago, after University of Delaware botanist Harsh Bais agreed to mentor 16-year-old Connor Sweeney on a research project. The ecstatic high school student got to work right away, spending all his free time, including weekends and summer breaks, in Bais's lab at the Delaware Biotechnology Institute. Conner's High School project entailed culturing Arabidopsis thaliana, also known as mustard weed, for use in experiments. The young researcher would place the seeds in Petri dishes and test tubes filled with agar to promote growth. Agar is is a jelly-like substance, obtained from algae. It is used in many Asian desserts. The seeds would germinate about six days later and transform into delicate three-inch saplings with bright green leaves.

    One day, Sweeney sliced a mustard weed leaf in two spots mimicking an insect bite to see how it would begin the repair process. The following day, the young researcher was surprised to find that while the injured plant remained unchanged, the roots of the neighboring young mustard weed sapling had grown considerably longer and even had lateral offshoots.To see what was triggering the growth, the scientists conducted further tests and discovered that the injured plants were releasing volatile organic compounds (VOCs) to warn its neighbors of the impending danger. 

    The researchers are not sure what the volatile organic compounds comprise, or the length of time they persistin the atmosphere. Although the VOCs are still a bit of a mystery, if you go through a field of grass after it's been mowed or a crop field after harvesting, you'll smell these compounds. This is not the first study that’s analyzed plants ‘talking’ to one another. In previous studies conducted on willow trees, poplars, and sugar maples, scientists observed that when warned about a possible insect attack, nearby uninjured plants begin spewing out bug-repelling chemicals to ward off the attack. Who would have thought that plants were so smart and resourceful?