Education, Environment, Latest News, Vaageesha Das

Insects, plants communicate, too

There are many ways a person can communicate with other people: talking, signing in a sign language, texting, calling, through reading, or through writing.

 We know that animals have their own specific set of sounds they make to talk to each other. Ants release a chemical throughout their lives that lets  other ants know  they are still alive. When they die, these chemicals gradually stop being released and the other ants take the dead ants and throw them off the nest so  if the ant  died from a disease, the disease would not be released into the nest. 

So, it seems that there are many species that communicate with each other, but what about plants?

Just like ants, plants send off chemicals to communicate whether they are in danger. One way plants send messages to each other is through the air. Plants such as sagebrush and lima beans can detect these airborne messages. 

An experiment was done on sagebrushes in which insects damaged the sagebrush. Other branches on the same sagebrush released chemicals that repelled  insects and branches on plants that were close to that sagebrush  also repelled the insects. 

There were also experiments in which scientists cut the leaves of the sagebrushes. The results of this experiment were the same: branches on the sagebrush being affected repelled bugs as did the surrounding plants’ branches.

The smell of cut grass is actually a signal to other plants that there is danger coming. The other plants grow faster, resist attacks and release seeds to make sure  their species still survives. Plants can also signal to other insects. If they sense that herbivores (animals that only eat plants) are coming to eat them, they can send signals to predatory insects that can kill the herbivores. 

But plants are competitive with each other, so  why do they warn other plants about dangers? In the experiment in which insects damaged the sagebrush, the other branches in the plant were also repelling bugs along with the neighboring plants. It is thought that plants are communicating with themselves but that the surrounding plants “overhear” or “eavesdrop on” the plant. 

The more similar the chemicals being emitted between two plants, the easier it is for them to communicate. This implies that a plant will be best able to understand its own messages. In the case of sagebrushes, tomato and tobacco plants can understand the sagebrushes’ messages. 

There is another way for messages to be spread: through the soil. For example, if tomatoes suffer from blight (a plant disease usually caused by fungi), they will activate genes and enzymes that aid in fighting diseases. Molecules produced by the tomato plants will travel to other plants which will signal to those plants to activate its immune system. 

It is also plausible that plants send electrical signals. In an experiment, scientists placed microelectrodes on Arabidopsis thaliana (the plant equivalent of a lab rat)’s leaves and leaf stalks. Egyptian cotton leafworms began eating the plant. Where the plant was being eaten, there were also releases of voltage (electric force) changes. Jasmonic acid, a defensive compound, began to accumulate. The genes that helped to transmit the electrical signals produced channels just inside the plant’s cell walls. These channels regulated the passage of charged ions. 

So, it seems that plants do in fact communicate with each other. They are able to send other plants messages, receive messages, and change their internal chemical balances based on these messages. Understanding how plants talk can help us figure out how to protect species.

Vaageesha Das  is a sophomore at Morgantown High School.

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