It is human nature to want to study the world: nature, society, and even oneself. Even in ancient times, many sciences appeared, which indicate that the study of the world began several thousand years ago. One of the oldest sciences is botany. What is botany, what does it study, what is the meaning of this word? Let's figure it out.

“Botany” translated from Greek means “grass, greenery, plant.”

Meanings of the word "botany"

• Botany is the science of plants. She studies their structure, living conditions, and evolution of development. Scientists believe that biology was one of the first sciences. People, having switched to a sedentary lifestyle, began to grow plants and engage in farming, so their interest in plants was very high. Today, botany is a multidisciplinary science; there are many disciplines in it (floristry, organography, phytocenology, biochemistry and others). The goal of botanists is to study the living conditions of plants, obtaining productive varieties that are resistant to both natural conditions and diseases. Research is very important for the development of the country's agriculture. For example: “Botany as a science in the 21st century is successfully developing, expanding the subject of research, improving methods and methods for studying the plant world of the planet.”
• Botany is also an academic discipline at a university, an academic subject at school, in which teachers introduce the basics of this science. For example: “In a botany lesson, the teacher talked very interestingly about the structure of a flower, showing an interesting presentation about its structure.”

What does botany study?

Definition 1

Botany- (from Greek. botane- vegetable, greens, herb, plant) is a complex science that studies plants. It comprehensively examines their origin, development, structure (external and internal), classification, distribution on the earth's surface, ecology (interrelations and relationships with environmental factors), and protection.

Like other sciences, botany has its own prehistory. Its origin can be traced back to ancient times, when people were just beginning to use plants for their practical needs (food, treatment, making clothes, housing). For quite a long time, naturalists were engaged only in describing plants - their size, color, characteristics of individual organs, that is, for quite a long time, botany had only a descriptive character. This section of biology was formed in the $17th-18th centuries. The first attempts to systematize the plant world became the beginning of the use in botany of the comparative descriptive method, with the help of which plants were not only described, but also compared according to external (morphological) characteristics. With the invention of the microscope, botany was born, and later, thanks to the intensive development of science and the improvement of microscopic technology, the experimental direction began to dominate.

Picture 1.

Plants- is a source of more than ten biologically active substances that act on the human and animal body, in particular when consumed as food. Since plants are integral to human life, they have become the object of close study.

All plants are divided into $2$ large groups:

1. lower plants, or thalli (thalom);
2. higher plants, or leafy plants.

Lower plants include algae.

Higher plants include bryophytes (mosses and liverworts), pteridophytes (psilophytes, psilotes, horsetails and ferns), gymnosperms and angiosperms.

Lichens, fungi, and bacteria are studied separately.

Note 1

Modern botany- a multidisciplinary science that covers a number of sections: plant taxonomy, which deals with the classification of plants depending on similar general characteristics. It is divided into two parts: floristry and botanical geography. Floristry studies plant communities in a certain area. Botanical geography studies the distribution of plants on the globe.

Plant taxonomy- the main botanical discipline. She divides the entire plant world into separate groups and explains the family and evolutionary connections between them. This is an assignment from a special section of botany - phylogeny.

At first, researchers systematized plants only according to external (morphological) characteristics. Nowadays, for the taxonomy of plants, their internal characteristics are also used (features of the structure of cells: their chemical composition, chromosomal apparatus, environmental features). Plant morphology, which studies the structure of plants. This science is divided into microscopic morphology and macroscopic morphology (organography). Microscopic morphology studies the structure of plant cells and tissues, as well as embryology. Macroscopic morphology studies the organs and parts of plants.

Some sections of morphology were decided to be separated into separate disciplines:

• organography (studies plant organs),
• palynology (considers the structure of plant spores and pollen),
• carpology (deals with the classification of fruits),
• teratology (subject of study - deformities and anomalies in the structure of plants),
• plant anatomy, which studies the internal structure of plants;
• plant physiology, which studies the forms of plants in the process of their ontogenesis and phylogenesis, as well as the processes occurring in plants, their causes, patterns and relationships with the environment. It is closely related to taxonomy.
• plant biochemistry, which studies the chemical processes in plants associated with growth and development.
• plant genetics, which studies the genetic changes in plants that occur with or without human intervention.
• phytocenology, which studies the Earth's vegetation, determines dynamic changes in nature, as well as their dependencies and patterns (vegetation is a combination of all the plants in one area that make up the landscape;
• geobotany, which studies ecosystems, that is, the relationships between plants, fauna and factors of inanimate nature (the whole complex is called biogeocenosis).
• plant ecology, which studies plants in relation to their habitat and determines the ideal conditions for plant life.
• paleobotany, which studies fossil plants to determine their evolutionary history.

Botany is also classified according to its objects of study into:

• algology - the science of algae,
• bryology, which studies mosses, etc.
• The study of microscopic organisms in the plant world was also separated into a separate discipline - microbiology.
• phytopathology - deals with plant diseases that can be caused by fungi, viruses or bacteria.

Note 2

Depending on the object being studied, special branches of botany were identified: forestry, meadow science, swamp science, tundra science and a number of similar disciplines.

Traditionally, botany includes mycology- the science of mushrooms (from the middle of the 20th century they began to be classified as a separate kingdom), as well as lichenology - the science that studies lichens.

Subject of study of botany- these are plants, their structure, development, family ties, the possibility of their rational economic use.

Problems of botany:

1. Studying plants to increase their resistance, productivity and endurance.
2. Identification of new plant species and their application.
3. Determination of the effect of plants on the human body.
4. Determining the role of man in the development and preservation of the planet's vegetation.
5. Carrying out genetic transformation of plants.

Research methods in botany:

observation method- used at both microscopic and macroscopic levels. This method consists of establishing the individuality of the object being studied without artificial interference in its vital processes. The collected information is used for further research.

comparative method- used to compare the object being studied with similar objects, and to classify them, analyzing in detail similar and distinctive features in comparison with forms close to them.

experimental method- used to study objects or processes in specially created artificial conditions. Unlike the observation method, the experimental method provides for the special intervention of the experimenter in nature, which makes it possible to establish the consequences of the influence of certain factors on the object of study. The method can be used both in vivo and in the laboratory.

monitoring is a method of constant monitoring of the state of individual objects and the course of certain processes. modeling is a method of demonstrating and studying certain processes and phenomena using their simplified simulation. It makes it possible to study processes that are difficult or impossible to reproduce experimentally, or to directly observe in living nature.

statistical method- based on statistical processing of quantitative material collected as a result of other studies (observations, experiments, modeling), which allows it to be comprehensively analyzed and certain patterns established.

Note 3

Botany is a science that studies the vegetation cover of the earth's surface at all levels - molecular, cellular, organismal, population.

Each person closely interacts with the world of living nature and is a part of it. And if in general the laws of existence of the living world are studied by biology, then the plant world is within the scope of botany as its integral part.

Why is the science of plants called botany?

Plants were part of human interests long before the formation of botany as a science, from the most ancient times. The study of flora was directly related to the issue of survival: plants are food, building materials, material for making clothing, medicine and (which should never be forgotten) dangerous poisons. The accumulated knowledge and observations required systematization. Thus, the need for the formation of plant science arose.

In search of an answer to the question of why plant science is called botany, we need to travel back to the depths of centuries, because this teaching is one of the oldest natural sciences in the world. Botany (the science of plants) finally acquired the form of a coherent system of knowledge during the second half of the 17th - early 18th centuries.

The name of science, like many others, has Greek roots. Derived from the ancient Greek "botane". This word had several meanings; in the meaning of “pasture”, “feed” it was used no less often than in the meaning of “plant”, “grass”. It included everything that could be considered a plant: flowers, mushrooms, algae, trees, mosses and lichens. The word "botany" is a derivative of "botane", it meant everything that related to plants. That is, literally: botany is the science of plants. Therefore, asking the question why plant science is called botany, the answer must be sought in the Greek origins of systematizing knowledge about the plant world into the form of science.

The Birth of Botany as a Science

Even Aristotle, in his great work on animals, announced a similar scientific work on plants. It is not known for certain whether it is finished or not. Only some of its fragments have survived to this day. Therefore, Theophrastus is rightfully considered the founding father of botany as a science, the author of two fundamental works that became the basis of botany for the next 1500 years. And in the modern world, the value of the knowledge expressed by Theophrastus in his works is undeniable. This is the answer to the question why the science of plants is called botany. The Greek philosopher could not call it anything else.

But research in the field of botany is not limited only to the achievements of Western civilization. China also made a significant contribution, and there may even have been an exchange of scientific achievements, given the functioning of the Silk Road.

History of botany

The science of botany in its modern sense originated in the era of colonialism as a field of study by farmers of herbs and trees common in the region, as well as plants that people brought with them from distant travels. But man's deep interest in flora begins its history from Neolithic times. People not only tried to determine the medicinal properties of plants, the growing season, edibility, resistance to low-temperature climate conditions, yield and nutritional properties, but also to preserve this knowledge.

Before the advent of botany as a science, man had already studied plants from a scientific point of view. This circumstance explains not only the widespread use by people since ancient times of the medicinal properties of plants grown in the wild. Since the Bronze Age, the practice of growing cultivated plants has been widespread.

A new stage in the development of science - new knowledge

At the end of the 16th century, the microscope was invented, which determined the beginning of a special stage in the development of botany, opening up previously unknown new opportunities in the study of plants, spores and even pollen. Then science stepped even further, lifting the curtain on issues of reproduction and metabolism that were previously closed to humans.

Botany developed in close connection with the development of biology in general. As a result of scientific research, the entire living world was divided into kingdoms:

• bacteria;
• mushrooms;
• plants;
• animals.

Botany studies the kingdom of bacteria, fungi and plants. The development of botany as a science was of enormous importance. But in its early days, people were concerned with plants on their own, and most of the botanical gardens that became particularly common in the Western world were devoted to the classification, labeling and trading of seeds. And only centuries later they became the most important research centers.

plant kingdom

Plants can be found everywhere: on land (meadows, steppes, fields, forests, mountains), in water (in fresh water bodies, lakes and rivers, in swampy areas, in seas and oceans). Almost all plants are characterized by a sedentary lifestyle, the ability to convert solar energy into organic compounds, have rich reserves of chlorophyll, and convert carbon dioxide into oxygen, for which the plant cover of the planet is called the lungs of the Earth.

Unfortunately, due to various circumstances, many plants are among the rare or endangered, and this list is only growing every year. Many representatives paid for their beauty: people, without thinking about the enormous harm they cause to nature, blasphemously destroy plants for the sake of a one-day bouquet. Such a bitter fate befell forest lilies of the valley, water lilies, and dream grass.

To protect rare plant species from extinction, they are included in the Red Book and protected at the legislative level. The science of plants serves as the basis of knowledge for this document. And now this is our common task - to preserve the flora for future generations, so that both our children and grandchildren can see the unique beauty of the plant world that we were lucky enough to see.

Botany is a science that studies plants. It is a branch of the broader science of biology, which studies all living organisms on Earth. The subject of the study of botany is the external and internal structure of plants, their vital activity at various levels (cellular, organismal, etc.), evolution, taxonomy, growing conditions, dependence of plants on the environment, their role in human life, and much more. In other words, botanyis a complex discipline, consisting of subsections.

Botany is a fairly ancient science. Human life is highly dependent on plants, and therefore, since ancient times, he has been interested in the characteristics of their growth and development. Even in Ancient Greece, Aristotle made his contribution to botany, but much more - his student Theophrastus. In the Middle Ages, botany, like other sciences, hardly developed. Its new heyday began in the 16th-17th centuries. Europeans' visits to various continents led to the accumulation of extensive information about wildlife. Description of organisms and systematization of knowledge have become relevant. In addition, technical means (microscopes) are appearing that make it possible to study the internal structure of plants and their life processes.

Previously, the subject of botany included not only plants, but also mushrooms. However, later they were separated into a separate kingdom, and the science that studies them was called mycology. Fungi differ from plants primarily in their inability to photosynthesize. At the same time, mushrooms, like plants, lead an attached lifestyle and grow throughout their lives. That is why botanists have always had a desire to classify them as plants.

In living nature there are very unique organisms, which are difficult to attribute to one or another kingdom of life. An example of such organisms is lichens. We can say that they represent a close symbiosis of a fungus and unicellular algae or a symbiosis of a fungus and blue-green bacteria. What science should study them? Studies them lichenology. However, it is a branch of botany. Thus, due to the complexity of the living world, scientists have to make a number of conventions.

Today, more than 300 thousand plant species grow and live on Earth (sometimes their number is estimated to be up to 500 thousand). The variety of plants is enormous. These are unicellular and multicellular forms with a simpler or more complex internal structure, differing in habitats, methods of reproduction, and life forms. Modern plants include algae, mosses, horsetails, mosses, ferns, gymnosperms and flowering plants. The taxonomy of plants is complex, it took a long time to form and is definitely not formed yet. Some groups are classified into one taxon or another. In modern botany, genetic methods for studying the relationship of plants and their evolution play an important role. This leads to a revision of the previously established taxonomy and classification, and, therefore, a change in the sections of botany.

Until now, plants are usually divided into lower and higher. Algae are classified as lower plants, since their body does not have organs or tissues and is represented by a thallus. Science studies algae albgology, which is a branch of botany.

Despite the diversity of plants, they all have common characteristics. It is the combination of these characteristics that allows one or another organism to be classified as a plant. But each individual character may be present in other groups of organisms that are not the subject of botany. Even photosynthesis, which is the main characteristic feature of plants, is also observed in blue-green algae, which belong to bacteria, i.e. prokaryotes (their cells do not have nuclei). However, a couple of characteristics - the presence of a nucleus in the cells and the ability to photosynthesize - already make it possible to unambiguously classify the organism as a plant.

Botany studies not only individual systematic groups of plants and their vital functions, but also the significance of the plant world. The role of plants for the planet is enormous. They create organic matter, habitat conditions for other organisms, and change the composition of the atmosphere. Although plants are not the first organisms on Earth, it was their appearance that contributed to the development of the animal kingdom.

Plan

1. Botany - the science of plants.

2. General characteristics of plants.

3. Distribution of plants and their importance in the biosphere.

Basic concepts: botany, autotrophy, nutrition, respiration, photosynthesis, growth, development, phytohormones, growth movements, the importance of plants.

Botany - the science of plants

Botany is the science of plants, their structure, life activity, distribution and origin. This term comes from the Greek word "botane", which means "herb", "plant", "vegetable", "green".

Botany explores the biological diversity of the plant world, systematizes and classifies plants, studies their structure, geographical distribution, evolution, historical development, biosphere role, beneficial properties, and seeks rational ways to preserve and protect flora. And the main goal of botany as a science is to obtain and generalize new knowledge about the plant world in all manifestations of its existence.

Botany as a science was formed about 2300 years ago. The first written generalization of knowledge about plants that has reached us is known only from ancient Greece (IV-III centuries BC), and therefore the emergence of botany as a science dates back to this time. Theophrastus (372-287 BC), a student of the great Aristotle, is considered the father of botany thanks to his written works “Natural History of Plants” in 10 volumes and written work “On the Causes of Plants” in 8 volumes. In The Natural History of Plants, Theophrastus mentions 450 plants and makes the first attempt at their scientific classification.

In the first century AD. Roman naturalists Dioscorides and Pliny the Elder supplemented this information. Medieval scientists continued the accumulation of information begun by ancient scientists. During the Renaissance, in connection with the enrichment of information about plants, the need arose to systematize the plant world. Great achievements in organizing botanical knowledge belong to Carl Linnaeus, who in the mid-18th century introduced a binary nomenclature of plants, was the first to attempt a classification of the plant world and developed an artificial system, dividing the plant world into 24 classes.

Now botany is a multidisciplinary science that studies both individual plants and their aggregates - plant groups from which meadows, steppes, and forests are formed.

In the process of development, botany differentiated into a number of separate sciences, of which the most important are: plant morphology - the science of the structure and development of the main organs of plants; From it stood out: anatomy (histology) of plants, which studies the internal structure of the plant organism; plant cell biology, which studies the structural features of a plant cell; plant embryology, which studies the processes of fertilization and embryo development in plants; plant physiology - the science of the life activity of the plant organism, is closely related to the biochemistry of plants - the science of the chemical processes in them; plant genetics studies issues of plant variability and heredity; paleobotany (phytopaleontology) studies fossil plants and is closely related to plant phylogeny, the task of which is to reconstruct the historical development of the plant world; plant geography (phytogeography) - the science of the patterns of plant distribution on the globe; From it, plant ecology emerged - the science of the relationship between the plant organism and the environment - and phytocenology (geobotany) - the science of plant groups.

There are also a number of specialized disciplines that study individual groups of the plant world, for example, algology - the science of algae, lichenology - about lichens, bryology - about bryophytes, dendrology - the science of tree species, palynology - about the structure of spores and pollen.

General characteristics of plants

All plants have common features:

1. Plant organisms consist of cells. V Cell(from Greek kytos- cell) is the basic structural and functional unit of all living organisms, an elementary biological system that has all the signs of a living thing, capable of self-regulation, self-reproduction and development.

2. Plants are eukaryotes (eukaryotes). Eukaryotes (eukaryotes) are organisms whose cells have a nucleus, at least at certain stages of the cell cycle. Eukaryotes include unicellular, colonial and multicellular organisms.

3. Most plant organisms - autotrophy Autotrophy(from Greek autos - himself, trophe- nutrition) - organisms that independently produce organic substances from inorganic compounds using the energy of sunlight or the energy of chemical processes.

4. Plant cells contain plastidi (from the Greek plastos - sculpted): chloroplasts (from the Greek chloros - green and plastos - sculpted), chromoplasts (from the Greek chroma - paint and plastos - sculpted), leucoplasts (from the Greek leukos - colorless and plastos - fashioned).

5. Reserve substances - starch, protein, fats.

6. Plants are characterized by vital processes (metabolism): a) nutrition - the process of absorption and assimilation by plants from the environment of substances necessary to maintain their vital functions; According to the method of nutrition, plant organisms are divided into autotrophs and heterotrophs (organisms that use ready-made organic substances for their nutrition);

b) respiration - a set of physiological processes that ensure the entry of oxygen into the plant and the release of carbon dioxide and water; the basis of respiration is the oxidation (syn. oxidation) of organic substances (proteins, fats and carbohydrates), as a result of which energy is released in the form of ATP (adenosine triphosphoric acid), which is necessary for plant life; plants are aerobes (from the Greek aer - air) - organisms whose life requires free oxygen from the air;

c) thanks to chloroplasts, plants are capable of photosynthesis (from Greek photos- light, synthesis - connection) - the process of formation of organic molecules from inorganic ones due to the energy of the sun; Solar energy is converted into the energy of chemical bonds.

The process of photosynthesis consists of two phases:

1. The light phase occurs in the thylakoids of chloroplasts. The energy of light quanta is captured by chlorophyll molecules, which causes the transition of electrons to a higher energy level and their separation from the chlorophyll molecule. The electrons are captured by carrier molecules, which are also located in the thylakoid membrane. The electrons lost by chlorophyll molecules are compensated by separating them from water molecules in the process photolysis - decomposition of water under the influence of light into protons (H) and oxygen atoms (O). Oxygen atoms form molecular oxygen, which is released into the atmosphere:

The released protons accumulate in the thylakoid cavity. Electrons move through the thylakoid membrane. The energy of electron transfer across the membrane is spent on opening a channel for protons in the ATP synthetase complex. Due to the release of protons from the thylakoid cavity, ATP is synthesized. Finally, protons bind to specific carrier molecules (NADP-nicotinamide adenine nucleotide phosphate). NADP is capable of being reduced, binding with protons, or oxidized, releasing them. Thanks to this, the NADP H 2 complex is an accumulator of chemical energy, which is used to restore other compounds.

Thus, in the light phase of photosynthesis the following reactions occur:

2. in Dark phase does not depend on light (reactions occur both in the dark and in the light). It takes place in the chloroplast matrix. In this phase, glucose is formed from carbon dioxide (CO 2) that comes from the atmosphere. In this case, the energy of ATP and H+ is used, which is part of NADP o H 2. During the synthesis of carbohydrates, the CO 2 molecule is not split, but is fixed ("bound") using a special enzyme. CO 2 fixation - multi-stage process. A special enzyme binds CO 2 with a molecule that contains five carbon atoms (C) (ribulose-1,5-biphosphate). In this case, two tricarboxylic molecules of 3-phosphoglycerates are formed. These tricarboxylic compounds are changed by enzymes, reduced with the help of NADP o H 2 and ATP energy and converted into substances from which glucose (and some other carbohydrates) can be synthesized. Some of these molecules are used for the synthesis of glucose, and from others, p-carboxylic compounds are formed, necessary for the fixation of CO 2. Thus, the energy of light, converted during the light phase into the energy of ATP and other energy carrier molecules, is used for the synthesis of glucose.

The dark phase of photosynthesis can be described by the following equation:

Some of the molecules of synthesized glucose are broken down to meet the energy needs of the plant cell, the other part is used to synthesize substances necessary for the cell. Thus, polysaccharides and other carbohydrates are synthesized from glucose. Excess glucose is stored as starch.

The meaning of photosynthesis:

1) the formation of organic matter, which is the basis for the nutrition of heterotrophic organisms;

2) the formation of atmospheric oxygen, which ensures the respiration of aerobic organisms and creates the ozone shield of our planet;

3) ensures a constant ratio between CO 2 and A 2 in the atmosphere. Academician K.A. Timiryazev formulated concept of cosmic role

green plants. By receiving the sun's rays and converting their energy into the energy of bonds of organic compounds, green plants ensure the preservation and development of life on Earth. They form almost all organic matter and are the basis of nutrition for heterotrophic organisms. All oxygen in the atmosphere is also of photosynthetic origin. Thus, green plants are, as it were, an intermediary between the Sun and life on planet Earth;

d) transpiration (from Latin trans - through, spiro - I breathe, exhale) - the physiological process of the release of water in a gaseous state by living plants;

e) growth - an increase in the size of a plant organism or its individual parts and organs due to an increase in the number of cells through division, their linear stretching and internal differentiation; continues throughout the entire life cycle;

f) development - a set of qualitative morphological and physiological changes in a plant at individual stages of its life cycle; distinguish between individual development (ontogenesis) and historical development (phylogeny); normal individual development of a plant organism depends not only on external factors(light, temperature, moisture, oxygen, length of the photoperiod of the day), and also from internal factors and from their interaction; main internal factors there are phytohormones (Table 5).

Table 5

PLANT PHYTOHORMONES

Name of phytohormones	Functions	education
Auxins (from Greek auxein - I increase)	predetermines the growth of the apical bud, suppresses the growth of axillary buds, affects the differentiation of vascular tissue, determines growth movements, can lead to the formation of fruits without seeds, controls cell elongation	meristem cells (undifferentiated tissue from which new cells develop)
Cytokinins (from Greek - cell, cyneo - bring movement)	stimulate cell division, cause the growth of lateral buds, preserve the green color of leaves, delay tissue aging	root meristem, fruit
Ethylene	inhibits the growth of seedlings in length, retards the growth of leaves, accelerates the germination of seeds and tubers, promotes the ripening of fruits, aging of the body
Gibberellins	activate cell division, stimulate the elongation phase, bolting, flowering, bring seeds out of dormancy, can cause the formation of fruits without seeds, accelerate fruit development	leaves, roots
Abscisic acid	stress hormone, helps the plant adapt to unfavorable living conditions, delays growth processes, accelerates the fall of leaves and fruits, accelerates aging	leaves, fruits, root cap

Phytohormones (from Greek. phyton- plant, hormao - excite) - these are physiologically active substances produced by the protoplast (living content) of plant cells and affect growth and shape-forming processes; phytohormones are active in very small quantities and can both stimulate and inhibit certain processes (act as regulators); Artificial regulators of growth and development also influence the development of the plant organism (Table 6);

Table 6

ARTIFICIAL REGULATORS OF PLANT ORGANISM GROWTH AND DEVELOPMENT

Name of artificial regulator	Functions	For what purpose does a person use
Retardants (antihyberelin)	inhibit stem growth in length, have a beneficial effect on resistance to lodging	contribute to the creation of stunted forms
Artificial auxins	functions similar to natural auxin, in high concentrations act as herbicides (from lat. herba- grass, caedere- kill), that is, capable of destroying plants	used to control weeds
Defoliants	causing artificial leaf fall	to facilitate mechanical harvesting of cotton
Desiccants	cause wilting of the above-ground parts of the plant	to facilitate mechanical harvesting of root crops (carrots, beets), tubers (potatoes)

there are) growth movements - changes in the position of plant organs in space due to uneven growth processes (Table 7); Higher plants do not have specialized organs for active movement, but they are able to respond to various changes in the external environment and adapt to them.

Table 7

GROWTH MOVEMENTS OF PLANTS

Growth movements Nastiya (from Greek nastos- compacted, closed)	Definition growth movements of organs and parts of plants that occur under the influence of a uniform stimulus (changes in light intensity, temperature, etc.)	Examples photonasty- opening of flowers in the morning and closing in the evening; change in the position of the inflorescence depending on the change in the position of the sun (sunflower); thermonastia- opening of flowers from buds when moving them from a cold to a warm room; mechanonasty - drawing up a leaf from touching them (mimosa shy); fruit cracking when touched (tear-grass); Chemonastia - turgorny movements of guard cells of stomata in response to CO 2 concentration, growth bends of glandular hairs of sundews under the influence of nitrogen-containing substances, etc.
Tropizmi (from Greek tropos- turn, direction)	various movements (bends) of organs or their parts caused by the unilateral action of a stimulus	positive tropisms - movement of organs towards the stimulus (for example, leaves towards the light); negative tropisms - organ movements are directed away from the stimulus (direction of root growth away from light); Depending on the nature of the stimulus, they are distinguished: phototropism (exposure to light), geotro-pizmi (one-sided effect of gravity), hydrotropism (the effect of a humid environment), chemotropism (the effect of a chemical substance), trophotropism (the effect of nutrients)