Injured Plants Warn Neighbors of Potential DangerPosted By: Best Brains Sep-26, 2017
In a perfect world – or impeccably, a wonderfully strange world, plants and animals would speak the same language. Could you imagine this? Yet, it would certainly make being on top of the food chain sensitively challenging, it sure would be informative to know.
Most humans don’t give much credibility to the communication abilities of other kingdoms. Just because they don’t speak a language we understand, it doesn’t mean that plants are not getting messages to one another.
Plants carry some uniqueness as per their family structure and factors. You might not know of plants being particularly chatty, but in reality - they communicate remarkably well with each other. This is especially seen when faced with potential danger. However, there is a recent study about the growing body of research on how plants can communicate with each other. This study about plant science says that injured plants send some emergency signals to alert the neighbors to start helping build up their defenses.
The chain of events related to this study and discovery began about two years ago, when University of Delaware botanist, Harsh Bais, agreed to mentor sixteen-year-old Connor Sweeney on a research project. The ecstatic high school student got to work right away, after spending all his free time, including weekends and summer breaks, in the Harsh Bais lab at the Delaware Biotechnology Institute.
The project entailed culturing Arabidopsis thaliana, also known as mustard weed, that was used in experiments. Here the young researcher placed the seeds in Petri dishes and test tubes filled with agar to promote growth. You can see that the seeds would germinate about six days later and transform into delicate three-inch plantlets with bright green leaves.
To observe the plantlets transformation, Sweeney conducted several experiments in order to test the plant communication. He sliced a mustard weed leaf in two spots mimicking an insect bite to see how it would begin the repair process. While the following day, the young researcher was surprised to discover that while the injured plant remained unchanged, the roots of the neighboring young mustard weed seedling had grown significantly longer and even had lateral offshoots. You can see it in the below image.
The researchers were unable to believe what they saw as they have expected that the injured plant to put more resources into growing roots. But they didn’t see that according to the researcher Bais, who conducted a similar study in the year 2012. He found that soil bacteria living near the roots of a plant helped to boost its immunity by signaling the leaf pores, or stomata, to close in the company of pathogens. To safeguard that it was not the same system at work, Sweeney partitioned the plants to prevent the communication between their root bacteria and then repeated the experiment multiple times. But the results were the same all the time.
To see what was prompting the root growth, the scientists conducted more tests and learned that the injured plants were discharging volatile organic compounds (VOCs) to notify its neighbors of the approaching danger. Trusting that the strong plant was growing its roots to absorb more nutrients to strengthen its defenses, Bais and Sweeney began observing for combinations that help trigger the increase in size. For their surprise, each time an injured plant sent out a warning, its neighboring mustard weeds began expressing more Auxin, a key plant growth hormone. However, the researchers were not sure what the volatile organic compounds comprise, or the span of time they persist in the atmosphere. The study still continues to see the exact reasons.