Plant memory

We humans all know that there is memory, but will plants have memory? Plants have a beautiful green appearance and can purify the air. They can live in colder places than animals. For example, the flytrap, which people love and fear, will only close if it touches two hairs within 20 seconds. Maybe some plants do have memories.

Plant memory may really exist.

Plants are quiet and charming. They have a beautiful green appearance and can purify the air. They can live in colder places than animals. Chauncey Maher, a philosopher at Dickinson College, suggested that some plants also seem to have memory.

For example: the flytrap that people love and fear. Only when the two sensory hairs are touched and the interval is within 20 seconds will the insect trap be closed. Some people think that this is to ensure that food such as flies are caught, rather than catching the wrong leaves falling from the sky. In the words of some biologists and cognitive scientists, "Venus flytrap seems to remember touching a hair recently", and this memory process caused its closing behavior.

Moreover, the root growth of plants may also involve some kind of memory process. If the root system encounters obstacles during its descent, it will turn to one side. But if it is blocked again, it will return to the original downward trajectory. In addition, the phototropism of plants (that is, leaves follow the direction of the sun during the day, which reminds us of memories)-at night, they will turn back to the direction in which the sun rises in the morning. They seem to be able to edit, store and obtain this information.

However, the difficulty lies in that these plant behaviors do not quite conform to the memory model usually put forward by psychologists-fragmented memory, that is, movies or life fragments recalled in people's minds; Procedural memory, that is, learning various skills; Semantic memory is to recall things that are not personally experienced, such as Tokyo, the capital of Japan, or a wonderful article about plant memory. If plants do have certain memories, they are not as obvious as these memories, which belongs to what fans of plant IQ call "minimum cognition".

It can be said that plants have no brains. However, some philosophers have another view on this. As far as we know, many animals do things unconsciously. They don't know what they are doing. Professor Dan Dent of Tufts University said, "Darwin told us that competition takes precedence over understanding." No brain, not necessarily no memory.

Plants also have memories?

As far as I know, a grass had a very bad afternoon a few years ago. It stayed quietly in the basin and no one bothered it. Then suddenly, it fell. Not 1 time, but 60 times-I'll explain what happened later.

But it is grass. Grass grows hard, and things are unpredictable. As far as I know, they will live as usual. Plants have no brains. They can't "remember" anything-they are not animals. So I don't think 60 falls will leave a lasting impression on them.

I was wrong. I just read an amazing paper by Monica Gagliano, an associate professor of biology at the University of Western Australia. She has a grass that not only "remembers" what happened to her, but also retains the memory for nearly a month. She witnessed it with her own eyes! This is a kind of grass:

Gardeners call mimosa "that kind of sensitive plant", because even if you gently touch it or throw it to disturb it, within a few seconds, the tiny leaves of mimosa will close, as if frightened and curled up, as if alert. It's interesting to watch it shy.

The falling distance of each pot of mimosa is about 15 cm, not 1 time, but 60 times in a row (every two falls are 5 seconds apart). These plants will slide into soft cushion foam as a buffer. Falling fast enough for plants to roll their small leaves into defensive arcs.

Whether to roll or not is a question.

But 15 cm is a short distance, which is not enough to harm plants. So, galliano wants to know, if she lets each of the 56 plants fall down 60 times, will these plants finally realize that "nothing bad will happen"? Will there be plants that won't roll up because of this?

In other words: Will plants use "memory" to change their behavior?

In order to find out the problem, she continued to do experiments. As she wrote in her paper, she soon "observed that some plants did not completely close their leaves when they fell". In other words, plants seem to find that falling won't hurt themselves, so more and more plants no longer protect themselves. Later, galliano told a group of scientists: "The leaves of the mimosa are finally completely open ... they don't care."

Is this really evidence that plants have memories? Or is it caused by other reasons? Sceptics think that maybe what we see is just a pile of tired plants. It's hard work and energy-consuming to roll up. After falling 60 times, they may just be "squeezed dry"-so there is no defense mechanism to trigger them.

However, in anticipation of this question, galliano put some "exhausted" mimosa in a shaker and shook it. The leaves will curl up immediately, as if to say, "Wow, this is different. This has never happened before. "

Adaptive training of mimosa under strong and weak light. At 0 minutes, each mimosa plant receives 60 drops; After 10 minutes, all mimosa leaves naturally return to the unfolded state, and then receive the second round of falling training. After that, there will be a round of 1, 2, 4 and 6 hours of training. After 6 hours of adaptation training, the mimosa was immediately placed on a shaker with a speed of 250 rpm and shaken for 5 seconds (DIS-hab), and then the last round of falling training was immediately carried out (after DIS-hab 10 min). In this experiment, 20 mimosa seedlings were released only once on the day of training. The vertical axis indicates the leaf opening of mimosa at each node. Image source: Reference [1]

She pointed out that the most reasonable explanation for plants to change their behavior is that they have the concept of "before". Mimosas didn't curl up because they found it unnecessary to do so before, remember.

After shaking the mimosa for a week, she let them fall again. This did not arouse their vigilance, and the mimosa still stretched its leaves. Week after week, she repeated the experiment until 28 days later, the plants still "remembered" what they had learned. This is a memory that has been preserved for quite a long time. Galliano mentioned that bees would forget what they found after a few days.

But how did they do it without brains?

"Plants have no brains." Galliano wrote in his paper, "But they have an elaborate ... signal transduction network." Will there be any "combination mechanism" of chemicals or hormones to maintain the memory of plants? This mechanism is essentially different from the animal brain, and it may be a distributed intelligence, and its operation mode is still unknown to us. But galliano thinks mimosa is enlightening us to understand this problem.

Michael Pollan, a contributor to The New Yorker magazine, once attended a scientific conference with galliano. In The New Yorker, he vividly described how galliano was laughed at by biologists, who scoffed at the idea that "plants also have' intelligence'". They insist that plants are basically genetic machines-they can't learn from experience or change their behavior. Pollan wrote that galliano's view "aroused strong repercussions, perhaps because she blurred the clear dividing line between animals and plants."

Plants are the third child in ten thousand years, not comparable to animals, not comparable to "champion" humans. Galliano endowed plants and animals with similar abilities, thus shaking this hierarchical difference and challenging the order of all things.

We always think that we humans are unique because we have a strong brain. Our trillions of neurons are the key to memory, feeling and consciousness. Creatures without brains obviously can't do this, so naturally, plants have no "memory".

But galliano said, maybe, they do.

At the end of the paper, she said, "Our experimental results have come to a clear and quite unusual conclusion: unlike previous views, memory may not need conventional animal neural networks and pathways; There is no doubt that the brain and neurons are a fine and abnormal system, but for the learning process, perhaps this is neither the only way nor the necessary element. " (fortune telling)

Plant memory in taste.

My sense of taste reminds me again and again that the days of chewing grass roots are gone. The sweet and sour taste, hidden in my body, is always fresh, and the days of chewing grass roots are gone forever with my childhood.

In the days of chewing grass roots, some experienced and knowledgeable children lead some ignorant children to dig grass roots, and older children decide what to eat and what not to eat. In that era of "half-grown boys eating poor old men", food was extremely scarce, and people's stomachs always felt hungry in the blink of an eye. The lack of clear soup and water forced greedy children to rack their brains to find more abundant food. After eating the next potato noodle, I feel that my mouth lacks flavor. It is an urgent task for every child's childhood to find something with a different taste from potato noodles.

In the barren yellow land, there are even a few kinds of weeds, and there are not many kinds for people to choose from. People's strong demand for food is not only because of hunger, but also because of an insatiable greed. People are too greedy to know what to eat. They are too greedy. Running to the ground with a small shovel, I couldn't remember what to dig at the moment, so I was so anxious that I fanned two shovels by mouth.

Everyone knows Xiao Spicy, but no one knows its alias. Its leaves are finely divided, light green but not enchanting, scattered in weeds, clustered or solitary, and there is nothing special compared with other weeds. And its chubby roots buried underground make people want to take a bite at first sight. It seems that a bite of spicy food can make a person's mouth double immediately and put it in his mouth to chew. The more you chew, the more fragrant it is. From the entrance, the fragrance has been fragrant to the stomach, and the internal organs have been turned upside down.

With a small shovel, I dug around a small spicy leaf of green leaves, and my saliva could not help flowing down. Take out a white fat horseradish from the soft soil, gently touch it with your fingers and you can eat it. First the smell of earth, then the pungent smell, you keep digging and eating until your stomach hurts.

In spring, small spicy tender leaves always arch out of the ground before other edible plants, and there is always a white and fat spicy horseradish hidden in the soil under each pinch of tender leaves. It is an extraordinary enjoyment to chew the newly dug spicy horseradish with boiled potatoes that have just come out of the pot. This kind of enjoyment that can be satisfied anytime and anywhere is only available in spring.

Horseradish is the most beautiful gift given to my childhood by the earth when food is scarce in a year. Its unique spicy taste made my childhood very sweet.

Spring and summer alternate, spicy horseradish is no longer fat, and the leaves on the ground begin to branch a lot, so it needs to absorb more nutrition from spicy horseradish, so spicy horseradish becomes old and can't eat any more.

Green leaves appear on the green seedlings on the plot. Pick an onion leaf, roll it into a roll, dip it in salt and pepper, and put it in your mouth. It smells delicious. If someone brings you a piece of white flour cake just out of the pot at this time, it's really too lazy to eat another pot of delicacies.

Since the leaves of green onions turned green, there have been more edible ingredients in the wild. There is a red root, which tastes sweet and astringent and grows new leaves. Generally, red roots do not live in groups. If you find a red root somewhere, the same red root may not appear nearby, so you need to be patient to find it. But my patience is very poor, and I am impatient when I find it. Licorice came into my sight at the right time. Finding a licorice is equivalent to finding a large area of licorice. The root system of licorice is very developed, and the shovel is not enough. The shovel can only dig out tiny lateral roots, while the huge main roots are hidden in the soil below one meter. The children are too weak to dig much. Licorice is too sweet and has a special medicinal taste. When chewing, my heart will be wet, so that at the sight of licorice, my internal organs will start to twitch and I can't help but want to vomit.

A green apricot tree attracted my sight from the ground to a high place. I began to peel the germ from the bud until the apricots were ripe and finished. Then I smashed the apricot kernel and ate the almond before I gave up. Apricots fall on the teeth, and if you can't eat a lot every day, you can't bite. The apricots on the tree are ripe, and every child's face tends to be consistent with the color of the ripe apricots on the tree, and all of them are yellow and emaciated. Apricots are sour when they sprout, until they are sour and mature, and it will end when they are sweet and sour. Every year when the apricots are ripe, the children can show their satisfaction and rebellion to all the food. It's like they ate a lot of fish and meat and didn't bother to eat potato noodles at all. Every meal, the village is full of young mothers with rice bowls in their hands, chasing children and stuffing them into their mouths.

No matter how hungry, children instinctively refuse anything bitter. Life is bitter enough. If people eat bitter things, they are prone to extreme pessimism. However, there is one thing that you should eat no matter how bitter it is, and that is herbs. Fortunately, people are not always sick, and taking medicine is not a regular thing. Some people, however, have been taking medicine three times a day without interruption until they feel that taking medicine is not the most painful thing, but the physical pain without medicine is the most painful thing.

The ups and downs in the taste all come from the land without exception. We don't have to question any kind of grass roots and food for us to chew, and regard it as a great pleasure to grow up. Pepper, red roots, onion leaves, licorice, sour apricots and herbs all constitute the "fireworks" in my childhood. These familiar smells grew with me.

Surprisingly, some foods of unknown origin keep pouring into our lives, but there is no experience for us to refer to. We always live a kind life as usual, and our hearts are full of expectations for a better life. I have to savor the taste similar to that of grass roots in the past from the roots and fruits of various plants at present, but it just feels similar. There are always some strange smells that can't be explained, trying to lower the taste standard of our food and missing the days of chewing grass roots. I can't help but express my strong dissatisfaction with some foods at present.

I miss when I chewed grass roots. I don't have to go back. I just tried in good faith to implant those scenes of chewing grass roots into our marching life and let our tastes return to normal. Anything that tries to hurt us will be destroyed by our tolerance. As long as it can awaken the taste memory that still exists in our hearts, even if there is only one inch of land for us to grow plants, don't let them be wasted and use those "ill-intentioned" foods.