Somewhere in the wetlands of South Carolina, USA, a fly landed on the surface of a pink plant. When exploring this new environment, it inadvertently touched a fine hair next to the lower body, so the fine hair was erected like a sword. When the fly touched the second fine hair again, the pink surface suddenly closed like a huge plant cockroach. This moment is only a tenth of a second, and the fly is here for a lifetime.
The sandbox tree is called the “dynamite tree”, which throws seeds far away, the distance of which is equivalent to the length of a standard swimming pool.
The sundew is called “Don’t touch me”. It can wrap the prey with sticky tendrils and fold the compound leaves within a few seconds after touching the prey…
Plants that can move at high speed have always attracted people’s attention. More than a decade ago, scientists began using high-speed digital cameras and computer models to study plant movements. Frame-by-frame analysis techniques and high-resolution lenses have finally provided researchers with a new way to look at plant movements in detail, so that everyone can see exactly what gives plants such amazing speed. The mechanism of plant manufacturing speed is varied: there are devices that can kick seeds like football players; devices that throw seeds like lacrosse players; and plants that even generate heat to launch seeds in an explosive way.
Jorge Fordell is a young scientist at Harvard University. At the beginning of this century, the teacher gave him a gift – a flytrap. Although this plant has no muscles, its athletic ability is amazing.
Ford quickly realized that professional advantages can help him understand the movement of the flytrap. He studied soft matter physics, which explored how certain materials (such as liquids, foams, and some biological tissues) change shape.
In 2005, Ford was one of the first researchers to rely on high-speed cameras and computer modeling to study the rapid movement of plants. The leaves of the flytrap are opposite each other, like an open book. Using ultra-high-speed cameras and computers, Ford’s team tracked the small changes that occur when the leaves are bent, and see how the special shapes of the leaves affect their speed.
When a fly or other prey triggers a “trap,” cells on the outer side of the leaf’s green expand, while cells on the inside of the pink do not swell. This difference produces a force that pushes the outer surface inward. Due to the excessive pressure, the original convex shape of the leaf (outwardly curved) quickly turned into a concave shape (curved inward like a bowl), and the flytrap quickly closed its “trap”. We can use the popular children’s toy – rubber cannon to understand the principle of this action. The rubber cannon is a small rubber hemisphere that can be flipped and flipped like a compressed spring. Since the rubber cannons store a lot of energy when it is turned over, which is called the potential energy, when it returns to its original shape, it converts the stored energy into kinetic energy, the energy of the movement, so that it can hit the old height. The same potential energy is also stored as the outer surface of the flytrap leaves is squeezed toward the inner surface. It is also like a rubber cannon, which instantly converts this energy into kinetic energy. This is one tenth of it. The key to closing the leaf trap in seconds.
While Ford studied the flytrap, Edwards and her husband led a group of young researchers to collect local plants on the Royal Island of Lake Superior, the world’s largest freshwater lake.
When a student lowered his head and sniffed the flowers of the Canadian grasshopper, he noticed that “something happened.” Out of curiosity, the research team brought the plant back to the lab and wanted to study the behavior of the plant by videotaping. But no matter how stimulating, the movement of this plant is difficult to capture. So Edwards upgraded the camera so that it could take 1,000 frames per second, but that still doesn’t work. Edwards recalls: “I think there is a problem with the camera.” So she found Whitaker at Williams College. Whitaker found that the reason was that the plant moved too fast and the camera could not capture it.
To this end, Edwards used a camera that can shoot 10,000 frames per second, and finally saw the movement mechanism of this plant for the first time: at first, the four petals of this plant gathered together, barely covering four A curved, arm-like structure that is a pollen-bearing stamen that protrudes from the petals. When an obese bumblebee or a curious human disturbs the plant, its petals separate and release the stamens. At this point the stamens are ejected and their acceleration can reach 2400g (the overload acceleration that the fighter pilot can tolerate before losing consciousness is about 9g). At this time, the stamens will eject a pollen bag (attached to the top of each stamen), and a cloud of pollen will fly to the wind or the object that caused the explosion.
The rich forms of motion exhibited by plants are as impressive as their speed. For example, the movement of the American dwarf mistletoe relies on heat. This parasitic plant grows on the bulbs of pine branches on the west coast of the United States. When such parasitic plants need to expand the territory, they will shoot the seeds at a rate of 20 meters per second. How such a feat is done, people have been puzzled.
In 2015, researchers finally discovered that the seeds were emitted by the heat produced by the plants themselves. Biologists use thermal imaging to study mistletoe, a technique that measures small changes in temperature in areas less than a millimeter. It has been found that they raise the temperature by about 2 degrees Celsius about a minute before the mistletoe will release the seed.
It turns out that secrets are hidden in the mitochondria. It is a structure in the body that produces heat that can cause cells to heat up. Cellular fever can cause a viscous gel to physically swell, and it is this expanding force that explodes the seed exploding.
In March 2018, scientists discovered a new plant that can eject a seed like an athlete with a bow and archery. This outstanding “athlete” is the petunia petunia. The flower has elongated seed pods, each of which has about 20 disc-shaped seeds, one of which holds each seed in place.
When the flower grows, the seed pod is tightened at the seam. When it matures, the seed pods will be pulled apart and the hooks inside will pull the seeds out. At this time, each seed will have a very fast rotation, and its rotation speed reaches 100,000 times per minute. This speed is the fastest in animals and plants. Interestingly, it is this spin that keeps these seeds stable during flight. This reason is understandable, there is a rifling in the barrel, the role is to make the bullet rotate before the exit, in order to increase the stability of the bullet flight.
Scientists say that a certain physical property of a plant is mechanical instability, and sometimes this instability develops as the plant grows, like a tightened bow. During the period, the plant can store the potential energy. When the “string” is pulled tight enough, it releases energy and converts the potential energy into kinetic energy, so the plant has a rapid response. Mechanical instability can allow the organ of the flytrap to close quickly and even allow some plants to jump. The energy stored and released provides plants with a means to speed up movement, helping some plants to quickly catch insects and helping plants to spread offspring. This is a racial advantage compared to other plants that do not have this skill.