If one leaf of the plant is damaged, signals about the threat are transmitted to other parts of it by changing the level of calcium in the cells.
When a mosquito bites your shoulder, you immediately brush it away, trying to prevent another bite. Plants cannot do this, but, as scientists have found, they are able to warn their not yet "attacked" parts of an impending threat.
An international group of researchers from Japan and the United States has proven that when any part of a plant is damaged, the glutamate present in it triggers calcium signaling in cells. This becomes a kind of warning system for other parts of the plant about damage. The research is published in the journal Science.
It is known that although plants do not have a central nervous system, like animals do, they can react to stimuli and distribute electrical signals throughout the body that resemble nerve impulses. The fact that plant cells are capable of generating an electrical signal was first discovered by the Indian scientist Jagadish Chandra Bose about a century ago.
Interestingly, plants can show external manifestations in response to stimuli. For example, change your orientation in space. The phenomenon when a plant bends towards a light source is called phototropism. There is a more familiar example, when parts of a plant react to changes in temperature: for example, mimosa, rolling leaves in the cold. This reaction is called thermotropism.
Researchers in Japan and the United States studied how gravity affects a plant in the cabbage family of the Arabidopsis. In order to find out how the level of calcium changes in plant cells under different conditions, the scientists observed labeled proteins that change the intensity of fluorescence when the concentration of calcium changes. During the study, an interesting phenomenon was accidentally discovered: when a part of a plant, for example a leaf, was damaged, a fluorescent glow spread through the rest of the parts, indicating that calcium signaling was taking place, that is, a sequential change in the concentration of calcium in the cells. This process is captured in the video below.
It turned out that the level of calcium in plant cells is controlled by glutamate - at the same time it plays the role of an excitatory neurotransmitter in the nervous system of animals. Thus, the signaling systems turned out to be incredibly similar to each other, although in plants, electrical signals move much slower than nerve impulses. However, this speed is enough for distant parts of the plant to have time to increase the level of hormones associated with protection. This is how plants prepare for future threats.
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Ksenia Murasheva