[ad_1]
Plants do not have eyes, no ears, no mouth and no hands. They have neither brain nor nervous system. Muscles? Forget them. They are stuck where they started, absorbing the sun and sucking up nutrients from the soil. And yet, when something happens to eat them, they feel it.
And they fight.
How is it possible?
"You have to think like a vegetable now," says Simon Gilroy, a botanist who studies how plants perceive and react to their environment at the University of Wisconsin-Madison.
"Plants are not green animals," says Dr. Gilroy. "The plants are different, but sometimes they are remarkably similar to the way animals work."
To reveal the secret operation of a plant's threat communication system a study published Thursday in Science, Masatsugu Toyota (now a professor at Saitama University in Japan) and other researchers from Dr. Gilroy's lab sent caterpillars as in the video above. They also cut leaves with scissors.
They applied glutamate, an important neurotransmitter that helps neurons communicate in animals.
In these videos and about a dozen other videos, they used a bright green protein to trace calcium and accompany the chemical and electrical messages of the plant. And they watched under a microscope the warnings that crossed the leafy green appendages, revealing that the plants are not as passive as they seem.
[[[[Like the Science Times page on Facebook. | Register for the Science Times Bulletin.]
Messages begin at the point of attack, where glutamate triggers a wave of calcium that travels through the veins of the plant or the plumbing system. The deluge triggers stress hormones and genetic switches that open the arsenals of plants and prepare the plant to repel aggressors – without any thought or movement.
Like animals, plants are eukaryotes – multicellular organisms – that separate from a common ancestor called Luca there are billions of years. To survive, we feel all the threats, transmit messages about them in our bodies or tissues and respond to these challenges. Our actions vary, adapted to the lifestyles we maintain in different environments, but most of our basic cellular machines are the same. Biology kept it like this: if it's not broken, do not fix it.
One of the mechanisms that our cells share is the fluctuating levels of calcium ions, which carry an electrical charge. In humans, this charge helps control when your neurons are sending messages. Changes in calcium ions make your heart or your muscles beat, allowing you to get up and go when something threatens you.
Plants, obviously, can not escape. But researchers knew that genes that make receptors a bit like glutamate trigger electrical signals that pass through plants after being injured. They activate genes elsewhere in the plant, allowing them to react.
With the help of glutamate, calcium ions can circulate, carrying their signal through channels that open like valves when glutamate inserts into these special receptor spaces, such as the keys in them. locks. These channels are not quite the same as those of the mammalian nervous system, but they are very similar and probably work in the same way. They brought Dr. Gilroy and his team to examine the flow of calcium ions.
To make the action visible, the researchers designed Arabidopsis plants, the botanical laboratory rat, to make a protein from jellyfish that shine under the microscope. This sensor, in this case, shines more when calcium levels increase.
They also made plants lacking glutamate-like receptors. In the latter, the fluorescent signal was weak:
The real surprise was the speed. The plant reacted in a few seconds and transferred the information from one leaf to the other in a few minutes, as long as they were connected to the vascular system. This is slower than your nervous system, but "for a plant biologist, it's the reservation," Dr. Gilroy said.
The factory also seemed to be able to detect the amount of damage because when they crushed a sheet, the factory responded everywhere:
Wherever calcium has been affected, the plant has produced jasmonic acid, a defense and stress hormone that they believe activates genes that somehow activate the chemical and physical defenses of the body. a plant.
Methyl-jasmonate, a product of jasmonic acid, for example, floats in the air like a jasmine-scented perfume. But for insects, this can be unpleasant or disrupt digestion and discourage customers from returning home. Physical defenses can also harden the cell walls of a plant, making them difficult to eat.
"The authors add a lot of pieces to the puzzle of how a localized sore triggers extensive defenses in the distal leaves," he said. Ted Farmer, a botanist from the University of Lausanne in Switzerland who described the electrical signal of the wound in plants.
But a lot remains a mystery.
"We are trying to understand what are the machines that run the whole system," said Dr. Gilroy.
What is not so mysterious is that plants and animals have a lot of problems. And while humans can deal with threats, plants too.
"They may have to be better than us to detect the environment because they do not have the luxury of getting up and going," said Dr. Gilroy.
Source link
