Plants sense, learn, transmit messages and even wage biological warfare. However, we are not yet able to see and understand this, says the Italian plant neurobiologist. The scientist believes plants are intelligent enough to even find solutions to problems. And, by the way, if plants disappear from the face of the Earth, our human species will also cease to exist within a week.
Plants sense, learn, transmit messages and even wage biological warfare. They provide us with oxygen and feed us. However, we are not able to see and understand it, says the Italian plant neurobiologist Stefano Mancuso.
The ancient philosopher Aristotle attributed plants to the class of primitive creatures. Since they are capable of reproduction, this thinker could not put them on a par with inanimate objects, but he did not believe that they represent something special.
Aristotle was color blind. For people with this disease, plants appear lifeless, and they do not understand their significance.
So says Stefano Mancuso, who heads the international laboratory of plant neurobiology at the University of Florence.
Plant neurobiology? What a science! Plants don't have a nervous system! Yes, plants really don't have brains, eyes, ears, or lungs. This means that important functions are distributed throughout the plant. Every part is important, but not irreplaceable. The herbivore can chew 95% of the aerial part of the plant and not kill it. The crippled plant will take offense and recover after a while.
The disadvantage of plants is that they are tied to one place. Therefore, since plants cannot escape in case of danger, they have to be sensitive to the environment. They use the same five senses as humans, and even a few that we don't have, says Mancuso.
Plants can sense moisture, gravity, and electromagnetic fields.
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This year, Mancuso's book The Plant Revolution: How Plants Invented Our Future was published in Finnish, and last year, a translation of his joint work with Alessandra Viola, “What Plants Think: A Secret Life Hidden from Prying Eyes” …
As the names suggest, the books explore the unusual abilities of plants. Plants can see, taste and smell. Light-sensitive phytochromes are most represented in leaves, as well as in tendrils, young shoots, and even wood. They respond to the power of light and the wavelength of light. They regulate the growth and flowering of the plant. Even in the underground part of plants, there are light-sensitive cells. With their help, the roots stretch further into the darkness.
The roots can also taste where important minerals are. More roots begin to grow in this direction. Plants can smell organic compounds. Most likely, the scent comes through the stomata in the leaves. What is happening there is still unclear.
There is a theory that the leaves may contain transport proteins that carry the scent molecules to the cells, says Applied Ecology professor Jarmo Holopainen at the University of Eastern Finland. Transport proteins also carry odor molecules from the cells that produced them, and this has already been documented in research. “Well, you and mimosa,” - say the Finns, if the interlocutor is offended by the nonsense. This delicate plant folds its leaves in response to touch.
With the help of Mimosa pudica, the researchers were able to prove that plants are capable of learning. This was discovered two hundred years ago by the famous biologist Jean-Baptiste Lamarck during an unusual experiment. He instructed his young colleague to transport the mimosa pots across the pavements of Paris. At first, all the plants covered their leaves in the shaking cart, but not for long. They realized that the shaking was not dangerous.
In 2013, Mancuso and colleagues repeated the modern version of Lamarck's experiment. The group placed the mimosa pots in special devices that quickly lowered the plants ten centimeters down. After about the eighth "little flight", the plants stopped rolling their leaves.
When the pots were later turned to a horizontal position and shaken, they covered the leaves again. The reason was not plant fatigue. The group repeated the experiment at different intervals. It turned out that mimosa is able to remember information for more than 40 days. Can you yourself remember what happened to you 40 days ago? How the memorization process works if plants don't have a brain is a big mystery.
What about hearing? Plants definitely have no hearing!
And here it is, says Carlo Cignozzi from the Italian commune of Montalcino. He let the vine listen to the works of Mozart for several years. Pleasant melodies accelerated the growth of the vine, the grapes ripened faster than on the vine, which was in complete silence. The grapes were juicier, more vibrant, and more polyphenols than other samples.
And that's not all: the music scared away insects, which meant that less money was needed to fight them. The effect would be the same if heavy metal rumbled from the speakers, says Mancuso, whose laboratory also took part in the experiment. Plants probably perceived sound waves through the vibration of cell membranes. The roots also felt the vibration and grew towards or away from her.
In Mancuso's laboratory, it was also recorded that the roots can make sounds. The researcher believes that click-like sounds occur when cells grow and the cell walls, made of cellulose, begin to crack. “If roots can recognize and produce sound, can they communicate? Maybe there are heated debates under the ground? Do plants use sound signals to tell where the water is? - says Mancuso.
Unsurprisingly, many botanists are skeptical of his research. However, the group was able to publish their articles in botanical publications - though not in such leading scientific journals as Science and Nature.
For a long time, it was believed that plants interact in different ways. The light bouncing off the flowers, as well as their color and fragrance, attract pollinating insects and birds.
Plants also transmit messages using various compounds. Thanks to this, they can even wage biological warfare. They defend themselves with substances that smell bad, taste unpleasant herbivores, or even turn out to be deadly.
A plant that has become the object of an insect attack can call for help, releasing the so-called informational chemical compounds. These evaporating “signal flares” attract plant destroyers such as predatory mites that prey on vegetable mites or ladybirds that feed on aphids.
The same substances can become a kind of "alarm signal" and call on neighboring plants to strengthen their chemical defense.
How do plants transmit internal signals? This question haunted botanists for a long time. Recently the Science newspaper presented its own answer.
Japanese Masatsugu Toyota, together with colleagues, modified rezukovidki, considered a model organism for experiments, so that the change in calcium levels was visual. Toyota has forced rezuvidki to produce a protein that only fluoresces in the presence of calcium.
When a leaf was cut off from a rezuhovidka, the damage began to glow. The flash spread in a wave until it reached other sheets. The signal transmission rate in plants was a millimeter per second. The leaves, receiving signals of danger, began to produce protective hormones.
Researchers noticed that the signal needs glutamic acid to work. The mechanism is exactly the same as in animals in danger: glutamic acid speeds up the transmission of messages along the nerves. Plants do not have nerves, but, according to Holopainen, their role can be played by channels through which water and nutrients enter.
Mancuso considers plants to be intelligent because they can find solutions to problems. One species turned out to be quite smart because he was able to come up with an amazing solution to a problem familiar to plants - herbivore attacks.
Boquila trifoliola, native to the temperate forests of Chile and Argentina, does what a liana usually does: wriggle on the ground or climb up nearby plants. It is amazing that she always imitates the leaves of the plant that grows nearby. If there are three different plants nearby, then Bokila three-leafed will change the shape, size and color of its leaves and even the arrangement of the veins, imitating the different plants around it.
This vine can mimic at least ten different species. She can even grow a thorn on a leaf if a nearby plant has one. It just can't repeat the prongs, write Chilean researchers Ernesto Gianoli and Fernando Carrasco-Urra in Current Biology.
How does a plant chameleon determine what to repeat? It is possible that some microorganisms use certain methods to transmit the genes of the reference plant to the copycat. Or does the vine take as a sample the volatiles that the plant produces? However, Bokila three-leafed copies precisely the plants closest in location, although it grows in a real cloud of secretions of different plant species.
Color blindness is still a common disease, although we are completely dependent on plants. Plants make up almost 99.5% of the biomass, that is, of all living things. Plants slow down the global warming process by removing carbon dioxide from the air. They give us oxygen, food, medicine, fiber, building materials, energy - and a lot of light.
If plants disappear from the face of the Earth, our species will cease to exist within a week. If a person is gone, all our best achievements will soon grow into fireweed.
Arya Kivipelto
