Defense Strategy of Plants – Warning Signal

The Diverse Defense Strategies of Plants

Plants use a variety of defense strategies to withstand the threat of predators. Well-known strategies include covering the body with sharp thorns to block access, growing tiny hairs called ‘trichomes’ on the surface of their leaves, stems, and flowers to make it hard for predators to climb up, and producing toxins on their own. Beyond these self-reliant efforts, some plants, like the African acacia tree, form symbiotic relationships with insects—offering habitat in exchange for protection from other animals and plants.

In this way, plants use various strategies to protect themselves. What is notable is that they do not stop at defending only themselves—they also carry out defense strategies to save their neighbors.

The Defense Strategy That Saves Neighbors – Chemical Warning

When faced with a crisis such as a predator’s attack, some plants release chemicals to send a warning signal to neighboring plants. This warning signal is a defense system that protects neighboring plants from a predator’s attack. Even though a plant may appear to be silently under attack, it is, in an unseen way, sounding a warning signal to save its neighbors.

The African acacia tree (Acacia) is a prime example. When herbivores such as goats or antelope begin to strip its leaves, the acacia immediately binds the tannin in its leaves with protein, turning it into a toxic substance that is hard to digest, thereby protecting itself. But the attacked tree does not stop at protecting itself—it also releases certain chemicals into the air. Neighboring trees that detect this warning signal carried on the wind proactively change the composition of their leaves and prepare their defenses even before they are attacked.

A study by a research team at the University of Delaware on Arabidopsis (Arabidopsis thaliana) also confirms this warning signal in plants. When researchers wounded its leaves to simulate an insect attack, the Arabidopsis immediately released volatile organic compounds (VOCs) into the air. Neighboring Arabidopsis plants exposed to these chemicals spread their fine roots out wide to absorb more nutrients in preparation for the threat.

Professor Harsh Bais, the botanist who led this study, noted that the released chemicals had no effect on the recovery of the wounded plant itself, but only activated the defense mechanisms of neighboring plants. He offered the view that the chemicals plants release are not for their own sake, but serve as a warning signal to alert nearby plants of danger.

The Lesson Plants’ Warning Signals Teach Us

The warning signals plants send for their neighbors carry great significance for humanity. Even plants, which have neither a brain nor a nervous system, try to save not only themselves but also their neighbors when facing a crisis. What about humanity, then, who prides itself as the crown of creation? Do we listen to the warning signals others send, prepare ourselves for danger, and pass warning signals on for the sake of others?

The Bible warns of judgment on a world that has broken God’s statutes and laws (Isaiah 24:1–5; 2 Peter 3:6–7). What is worth noting is that the Bible’s warnings of disaster have always come together with a message of salvation. At the time of the great flood in Noah‘s day, and before the destruction of Sodom and Gomorrah, God made known the way of salvation along with the warning of disaster (Genesis 7:10–23; 19:12–22).

What, then, is the signal of salvation that sounds together with the warning of disaster in this age? It is ‘Zion,’ the refuge where one can be protected even amid the final plagues.

Declare ye in Judah, and publish in Jerusalem; and say, Blow ye the trumpet in the land: cry, gather together, and say, Assemble yourselves, and let us go into the defenced cities. Set up the standard toward Zion: retire, stay not…

(Jeremiah 4:5–6)

Zion refers to the church that keeps the feasts of God (Isaiah 33:20). Jesus completed the spiritual Zion and granted eternal life and salvation through the New Covenant Passover (Matthew 26:17–28; John 6:53–54). The place where the New Covenant Passover is kept is the spiritual Zion prophesied in the Bible, and the perfect fortress of salvation that will protect humanity from the disaster the Bible warns of.

For an in-depth exploration of Zion, please refer to the article, ‘Where is Zion, God’s Dwelling Place?’

The defense strategy of plants goes beyond protecting themselves—it is a way of saving their neighbors together. Now is the time for us to learn that selflessness. God desires that even one more soul escape disaster and reach salvation. Having first realized the warning of disaster and the message of salvation, we, too, must not remain silent. Making known to the world the spiritual Zion where the New Covenant Passover is kept—that will become the signal of life carrying God’s will.

〈References〉

• Encyclopaedia Britannica, “Botanical Barbarity: 9 Plant Defense Mechanisms”
• ‘Plants call 911, too’, University of Delaware website, May 16, 2017.
• ‘The Chemical Warfare of Plants … When Goats Approach, Acacia Changes the Taste of Its Leaves’, JoongAng Ilbo, May 19, 2014.