At first glance, the world of plants seems to be motionless. But upon observation, one can see that this is not entirely true. Plant movement is very slow. They grow, and this proves that they make certain growth movements. If you plant a bean seed in the soil, under favorable conditions, it begins to grow, drilling through the soil, bringing out two cotyledons. Under the influence of heat and light, they begin to turn green and move upward. Within two months, fruits appear on the plant.
Plant growth rate
To notice the movement, you can take a special video. As a result, what is happening during the day can be observed in a few seconds. The growth movements of plants are accelerated hundreds of times: before our eyes, sprouts make their way through the soil, buds bloom on trees, flower buds swell and bloom. In reality, bamboo grows very quickly - inminute by 0.6 mm. Some fungal fruiting bodies have an even higher growth rate. Dictiophore increases in size by 5 mm in just one minute. Lower plants have the highest mobility - these are algae and fungi. For example, chlamydomonas (algae) can quickly move in the aquarium with the help of flagella to the sunlit side. Many zoospores also move, which serve for reproduction (in algae and fungi). But back to more complex plants. Flowering plants make various movements that are associated with the growth process. They are of two types - these are tropisms and nastia.
Tropisms
Tropisms are called one-way movements that react to any irritating factors: light, chemicals, gravity. If you place seedlings of barley or oat grains on the windowsill, after a while they will all turn towards the street. This movement of plants towards the light is called phototropism. Plants make better use of solar energy.
Many people have a question: why does the stem stretch up and the root grows down? Such examples of plant movement are called geotropism. In this case, the stem and root react differently to gravity. The movement is directed in different directions. The stem stretches upward, in the opposite direction from the action of gravity - this is negative geotropism. The root behaves differently, it grows in the direction of gravity movements - this is positive geotropism. All tropisms are divided intopositive and negative.
For example, a pollen tube sprouts in a pollen grain. On a plant of its own species, growth goes straight up and reaches the ovule, this phenomenon is called positive chemotropism. If a pollen grain falls on a flower of a different kind, then the tube bends during growth, does not grow straight, this process prevents the fertilization of the egg. It becomes obvious that the substances isolated by the pestle cause positive chemotropism on plants of their own species, and negative chemotropism on alien species.
Discovery of Darwin
Now it is clear that tropisms play a big role in the process of plant movement. The first to study the causes that cause tropism was the great Englishman Charles Darwin. It was he who found that irritation is perceived at the point of growth, while bending is perceived below, in the zones of cell stretching. The scientist suggested that a substance arises at the point of growth, flowing into the zone of tension, and bending occurs there. Darwin's contemporaries did not understand and did not accept this innovative idea of his. Only in the twentieth century, scientists empirically proved the correctness of the discovery. It turned out that in the cones of growth (in the stem and root) a certain hormone heteroauxin is formed, otherwise - beta-indoleacetic organic acid. Lighting affects the distribution of this substance. There is less heteroauxin on the shady side, and more on the sunny side. The hormone speeds up the metabolism and therefore the shadow side tends to bend towards the light.
Nastia
Let's get acquainted with other features of the movementplants called nastia. These movements are associated with diffuse effects of environmental conditions. Nastia, in turn, can be positive and negative.
Dandelion inflorescences (baskets) open in bright light, and close at dusk, in poor light. This process is called photonasty. In fragrant tobacco, the opposite is true: when the light decreases, the flowers begin to open. This is where the negative aspect of photonasty comes into play.
When the air temperature drops, saffron flowers close - this is a manifestation of thermonasty. Nastia basically also have uneven growth. With a strong growth of the upper sides of the petals, the opening occurs, and if the lower sides have more strength, the flower closes.
Contractile movements
In some species, the movement of plant parts is faster than growth. For example, contractile movements occur in oxalis or shy mimosa.
Shamey mimosa grows in India. She instantly folds her leaves if touched. Oxalis grows in our forests, it is also called hare cabbage. Back in 1871, Professor Batalin noticed the amazing properties of this plant. One day, returning from a forest walk, the scientist collected a bunch of sour. When shaking along the cobblestone pavement (he was driving a cab), the leaves of the plant folded. So the professor became interested in this phenomenon and a new property was discovered: under the influence of irritants, the plant folds its leaves.
In the evening, sour leaves also fold, and incloudy weather it happens earlier. In strong sunlight, the same reaction occurs, but the opening of the leaves after that is restored after about 40-50 minutes.
Movement mechanism
So how do the leaves of oxalis and bashful mimosa make contractile movements? This mechanism is associated with a contractile protein that comes into action when stimulated. With the reduction of proteins, the energy produced in the process of respiration is spent. It accumulates in the plant in the form of ATP (adenosine triphosphoric acid). When irritated, ATP decomposes, the bond with contractile proteins breaks up, and the energy contained in ATP is released. As a result of this process, the leaves are folded. Only after a certain time, ATP is formed again, this is due to the process of respiration. And only then can the leaves open again.
We found out what movements plants (mimosa and oxalis) make in response to irritating factors. It is worth noting that the reduction occurs not only with changes in the environment, this is also due to internal factors (the process of breathing). Oxalis folds its leaves after dark, but it does not begin to open them at sunrise, but at night, when a sufficient amount of ATP accumulates in the cells and communication with contractile proteins is restored.
Features
The movement of plants given in the example has its own characteristics. Observation of oxalis in nature brought some surprises. In a clearing with a mass of plants of this species, when everyoneplants, the leaves are open, there were specimens with closed leaves. As it turned out, these plants bloomed at that time (although in summer the flowers have a nondescript appearance). When flowering, oxalis spends a lot of substances to form flowers; it simply does not have enough energy to open leaves.
If we compare animals and plants, it is worth noting that the contractile movements in them are affected by the same reasons. There are similar reactions to the stimulus, while there is a latent period of irritation. In acid, it is 0.1 s. In mimosa with prolonged irritation, it is 0.14 s.
Reaction to touch
Considering the movements of plants, it is worth noting that there are instances that are able to change the tension of tissues when touched. The well-known mad cucumber in its mature state, when irritated, is able to spit out the seeds. The turgor of the inner tissue of the pericarp increases unevenly with the loss of water or with pressure, and the fetus immediately opens. A similar picture occurs when touching a touchy plant. It is possible that not growth, but contractile movements predominate in nastias, but scientists are still investigating this.
General classification of plant movements
Plant movements are generally classified by scientists as follows:
- Movement of the cytoplasm and organelles - intracellular movements.
- Locomotion of cells using special flagella.
- Growth based on elongation of growth cells - this includes elongation of roots, shoots, axial organs, leaf growth.
- Growth of root hairs, pollen tubes, moss protonema, that is, apical growth.
- Stomatal movements - turgor reverse movements.
Locomotive movements and movements of the cytoplasm are inherent in both plant and animal cells. The remaining types belong exclusively to plants.
Animal movement
We have considered the basic movements of plants. How do animals move and what are the differences between these processes in animals and plants?
All types of animals have the ability to move in space, unlike plants. It largely depends on the environment. Organisms are able to move underground, on the surface, in water, in the air, and so on. Many have the ability to move in many ways similar to human. It all depends on various factors: the structure of the skeleton, the presence of limbs, their shape, and much more. The movement of animals is divided into several types, the main ones include the following:
- Amebic. Such movement is typical for amoebas - organisms of the same name. The body of such organisms is unicellular, it moves with the help of pseudopods - special outgrowths.
- The simplest. Similar to amoebic locomotion. The simplest unicellular organisms move with the help of rotational, oscillatory, wave-like movements around their own body.
- Reactive. This type of movement also characterizes the simplest organisms. In this case, forward movement occurs due to the release of special mucus, which pushes the body.
- Muscular. The most perfect type of movement, which is characteristic of all multicellular organisms. This also includes man - the highest creation of nature.
What is the difference between the movement of plants and the movement of animals
Each animal in its movement pursues some goal - this is the search for food, change of place, protection from attacks, reproduction and much more. The main property of any movement is the movement of the whole organism. In other words, the animal moves with its entire body. This is the main answer to the question of how plant movements differ from animal movements.
The vast majority of plants lead an attached existence. The root system is a necessary part for this, it is located motionless in a specific place. If the plant is separated from the root, it will simply die. Plants cannot move independently in space.
Many plants are able to make any contractile movements, as described above. They are able to open petals, fold leaves when irritated, and even catch insects (flycatcher). But all these movements occur in a certain place where this plant grows.
Conclusions
The movements of plants differ in many ways from the movements of animals, but still they exist. Plant growth is a clear confirmation of this. The main differences between them are as follows:
- The plant is in one place, in most cases it has a root. Any kind of animal is able to move in space in a variety of ways.
- In theiranimal movements always have a specific purpose.
- The animal moves with its whole body, entirely. The plant is capable of movement by its separate parts.
Movement is life, everyone knows this saying. All living organisms on our planet are capable of movement, even if it has some differences.
