Do plants warn each other when they are in danger?

Weather of Arabia - It seems that plants warning each other are similar to a fictional scene from a movie, where the enemy begins to attack a tree, but the tree confronts him, sends a warning message so that nearby trees respond to it, and sets up its own group of defenses, so that it can protect the forest.

It is worth noting that there is no need for magic in the real world to create this scene, as real trees on our planet can communicate and warn each other of dangers, and a recent study has revealed how this works.

How do trees warn each other when they are in danger?

Infected plants have been shown to release specific chemical compounds , which can infiltrate the healthy tissues of other plants, activating defense mechanisms within them. This deeper understanding of the process could help scientists and farmers boost plants' immunity against insect attacks or desertification well before they occur.

Masatsugu Toyota, the lead researcher for this study, which was published in the journal Nature Communications, noted that this study is the first of its kind, which highlights the possibility of “plant communication.” He added:

“Perhaps we will be able to leverage this system to alert entire plants and activate multiple responses to future threats or environmental changes, such as water shortages.”

In the 1980s, the idea of “communication” trees began to take root in environmental awareness, as two ecologists conducted an experiment combining hundreds of caterpillars, webworms, and branches of willow and alder trees to monitor the trees’ response. They discovered that trees that were in danger began to secrete chemical compounds that made their leaves... It does not attract insects, and is difficult for them to digest, as a means of deterring their attacks.

Trees communicate and exchange chemical defenses at a distance

But the most curious aspect is that scientists discovered healthy trees of the same species, located 30 to 40 meters away from the damaged trees, without having roots connected to the damaged trees. However, these trees were secreting the same chemical defenses in preparation for repelling insect attacks, and the Scientists then produced similar results when they studied damaged maple and poplar trees.

These early research teams had the nascent idea that trees would send chemical signals to each other through the air, what is known today as “phytoeavesdropping.” Over the past four decades, scientists have observed this plant cell-to-plant communication in more than 30 plant species, including lima bean, tobacco, tomato, sagebrush and flowering plants in the mustard family. However, there has been no clear understanding of the bioactive compounds responsible and how to detect them until now.

Andre Kessler, an expert in plant ecology who was not involved in this research, noted the importance of this discovery, saying:

“There's been a bit of a debate in this area, first, how these compounds are generally absorbed by the plant, and then how they change the plant's metabolism based on the signals that are detected.”

The language of plants... How do they interact and communicate with their surrounding world?

Although plants do not have ears or eyes to communicate like humans, previous research has revealed that they are able to interact with the world around them by releasing chemicals known as “volatile organic compounds,” which we can smell and similar to how humans speak with language. Plants use a variety of these compounds for different purposes. Some are used to attract pollinators, while others serve as a defense against predators.

Among these compounds, there is a specific class that is emitted when a plant is exposed to injury, namely green leaf volatiles. These compounds, as the name indicates, are produced by most green plants that bear leaves, and are present when the plant is exposed to any physical harm, such as the pleasant smell that emanates from fresh grass.

Plant response

In the new research, Toyota and his team conducted a series of experiments in which they crushed leaves by hand, placed caterpillars on Arabidopsis mustard and tomato plants with the aim of stimulating the emission of a range of green leafy volatiles, and then sprayed the resulting vapors on healthy plants to examine their reaction.

To track the responses of healthy plants, the team genetically modified these plants to make calcium ions signal when they interact within individual cells. Calcium signaling plays an important role in the cellular functions of most organisms on Earth, including humans. When neurons receive an electrical signal, they open. Ion channels, allowing calcium to flow in. This increase in calcium can trigger the release of neurotransmitters, which results in muscle contraction in muscle cells.

Toyota confirmed that calcium signals play a similar role in plants, and depending on the type of plant, calcium signals can contribute to sending messages that lead to the closing of plant leaves or even the digestion of insects.

After multiple tests for leafy green volatiles, the team made the discovery that only two of these substances appeared to increase intracellular calcium signaling. They also detected an increase in calcium signaling for the first time in the guard cells that make up the pores of plant leaves, known as stomata. Importantly, it appears that these compounds can infiltrate the internal tissues of the plant.

How can calcium signaling enhance defenses against insects?

According to Kessler, a professor at Cornell University,

“These materials cannot easily seep through the surface of the plant.” “They have to pass through stomata, which allow the plant to inhale carbon dioxide and exhale oxygen to carry out photosynthesis.”

Toyota says that calcium signaling is like a switch to activate defensive responses in the plant. After increasing the signal, the team discovered that the plant increases the production of certain gene expressions for protection. For example, the plant can begin to produce certain proteins that prevent insects from chewing the leaves, resulting in weakened Insects.

Toyota explains:

“If you have plants with a lot of these genes, they become very strong against herbivorous insects.”

With this new understanding, researchers say plants can be fortified against threats and stresses before they happen, akin to giving plants a "vaccine." For example, healthy plants could be exposed to plants infested with insects or leaf-related volatiles to boost their genetic defenses, reducing Farmers need to use pesticides. This discovery may also contribute to making plants more resilient during periods of drought, allowing the plants to retain additional amounts of water.

Adapting plants to environmental challenges

Kessler pointed out that when plants are exposed to drought early in their lives, they are more able to deal with this challenge better compared to plants that were not exposed to drought, and this is linked to a complete change in the plant’s metabolism, and in this context, plants adapt themselves to face harsh environmental conditions and develop different responses to meet the challenges.

In the course of its study of plants, Toyota has conducted research that includes planting several seeds for future research. One of the mysteries observed in this study is why only two leafy green volatiles enter the stomata and stimulate calcium signaling. The next step in this research includes Identifying different receptors in plants that may be related to the chemical structure of the two mentioned compounds.

It should be noted that plants also show specific responses to insect attacks, meaning that they react differently depending on the species of herbivores that feed on them. This behavior is impressive, and is being studied in depth by Kessler and his team.

Briefly, Kessler suggests that the ability of plants to adapt to challenges around them and develop diverse responses expresses a kind of intelligence in the plant world and his study of these matters contributes to our understanding of how plants interact with the environment and adapt to changes.

Also know:

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The smallest flowering plant on Earth may become food and a source of oxygen for astronauts

Sources:

washingtonpost