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Vegetative organs of plants - what they are, what types. Structure of plants Functions of the main organs of plants

It is impossible to imagine the earth's landscapes without plants. They play an important role in the planet's ecosystem, maintaining the necessary oxygen content in the air and creating fertile layer soil. The vegetative organs of plants help them perform basic life functions and interact with the environment.

Vegetative organs are organs that perform functions related to individual life each plant.

In lower plants (algae and yeast), the vegetative body is not divided into organs. Higher plants have such organs; they perform the functions of nutrition and respiration. Thanks to them, the plant exchanges substances with external environment, multiplies and grows. Plants do not have as many organs as animals, but they can also have different structures and are divided into species.

What plant organs are called vegetative and their types

Vegetative organs include only three parts of the plant - root, stem and leaf. In one plant they are often at different stages of development.

Vegetative organs can be basic, providing nutrition and water supply, and second order.

Plants can reproduce vegetatively. The organs of vegetative propagation of plants are aboveground and underground shoots.

Main vegetative organs of plants

The main vegetative organs include the root and leafy shoots. They perform vital functions for the plant.

The root and its main functions

Each plant has its own type of root.

The root performs the functions:

fixing the plant in the ground;
soil nutrition with water and mineral salts in accessible form;
supply of nutrients;
reproduction.

The root is an axial organ with radial symmetry. Its tip is covered with a root cap, under which there is educational tissue. Thanks to this tissue, it grows.

All roots are divided into main, lateral and adventitious, and all of them together form the root system. In dicotyledons root systems taproot, with a predominance of the main root. Monocots have fibrous root systems.

Leafy shoots

In the process of evolution, plants adapted to a terrestrial lifestyle due to the appearance of leafy shoots. Later, leaves and roots formed on them.

Escape function is air feeding.

The first shoot grows from the embryonic bud during seed germination. Then it forms side shoots of the second order, and those, branching, in turn, form shoots of the third order, and so on.

Depending on the type of plant, the types of branching are distinguished:

sympodial is characteristic of many angiosperms and orchids;
monopodial (palms, phalaenopsis and gymnosperms);
dichotomous (mosses, ferns).

Depending on the functions they perform, shoots are divided into the following types:

vegetative;
generative;
vegetative-generative.

Shoots bearing flowers are called peduncles.

As a result of the plant’s unusual lifestyle and its adaptation to environmental conditions, modified above-ground shoots appeared. These include: head of cabbage, tendril, spine, aboveground stolon. In some plants, flattened green shoots perform the role of photosynthesis instead of leaves, for example, cladodes in cacti, Decembrists and prickly pear, phyllocladies in butcher's broom, asparagus, phylanthus.

Modified underground shoots have lost the functions of photosynthesis, but they can store nutrients and contribute to the resumption of plant growth and reproduction.

Such escapes include:

caudex;
stolon;
bulb;
tuber;
corm;
rhizome.

The collection of plant tissues that form a shoot is called a meristem. The plant organs located on the shoot or stem (buds and leaves) are connected by a single conductive system.

Autonomic organs of the second order

Stems and leaves are the main parts of the shoot, but are considered as second-order organs. In addition, there are always buds on the shoot.

Leaves

Green Vegetation on Earth is provided by the pigment chlorophyll, which is found in leaves and ground shoots.

Leaves are the external organs of plants that perform important functions:

gas exchange;
moisture evaporation;
photosynthesis.

In the process of adaptation to growing conditions, leaves have developed special adaptations.

Shiny leaves reflect sunlight.
A waxy coating on the surface of the leaf plate prevents the evaporation of moisture. Pubescence performs the same function.
Thanks to its rugged leaves, the plant can withstand gusts of wind more easily.
To protect against herbivores, some leaves, such as those of eucalyptus, produce aromatic oils and poisons.

Modified leaves include:

trappers - characteristic of carnivorous plants that feed on insects;
succulent - thick and fleshy leaves that accumulate moisture and nutrients;
leaf spines are derivatives of the leaf blade (barberry) or spiny stipules (acacia), which protect plants from being eaten by herbivores;
tendrils - formed from the upper part of the leaves and help the plant cling to the support (peas).

The leaves differ in shape (there are about 30 varieties in total), type of venation, stipule, and type of petiole. According to the division of leaf blades, there are two main forms of leaves - simple and complex, when several leaves are located on one petiole.

Stem

Like the skeleton in humans and animals, the stem in plants serves as a mechanical axis for supporting the remaining vegetative organs. It also conducts nutrients.

Stems are classified according to various characteristics:

type of branching;
location relative to soil level;
degree of lignification;
direction and nature of growth;
cross-sectional shape.

Modified stems can be aboveground or underground. They perform certain functions that are important for the life of plants.

Modified vegetative organs

Only some modified aboveground and underground shoots are listed here. There are also antennae, spines, tuberidia, cladodes and stem-root tuberoids.

Rhizome

Rhizomes are mainly characteristic of herbs.

The leaves on the rhizome are represented by a scaly film, in the axils of which buds grow. Aboveground stems of the plant grow from one part of the buds, and roots from the other. An underground rhizomatous stem grows from the apical bud of the rhizome. The rhizome is resilient; its parts with buds are used for plant propagation.

Stolons

These are thin, elongated shoots with leaf primordia. They are short-lived, unlike rhizomes, but also contribute to the vegetative propagation of plants. In some stolons, the plant accumulates nutrients.

Tubers

An underground organ of a plant.

Tubers form at the top of the stolons. The tuber plant potato is well known to everyone; its tubers accumulate organic substances in the form of starch. On the surface of the tuber there are eyes - small depressions with buds, from which a new potato bush subsequently grows.

Bulbs

Bulbs are also underground shoots that can be spherical, oblong or pear-shaped. The bottom of the bulb is a modified stem, and the scales are leaves. The bulb is characterized by a fibrous root system. New bulbs are formed from the axillary buds - babies.

Kidneys

The role of buds is also great in the vegetative propagation of plants.

A bud is a shoot primordium that forms in the axil of a leaf, at the top of a shoot, root or stem. The buds may be dormant and then they do not open, awaiting the onset of favorable conditions for growth, or a shoot immediately begins to develop from them. Vegetative propagation by above-ground shoots:

Some plants are propagated by leaf cuttings, for example, indoor flowers - Crassula, begonia, Saintpaulia.
Indoor dracaena successfully takes root using parts of the stem - stem cuttings.
Strawberries, wild strawberries and some grains multiply creeping shoots- “mustache”.
Shrubs, such as currants, blackberries, and raspberries, are successfully propagated by layering.

Reproduction by underground shoots:

Many herbs, trees and shrubs produce root shoots - these are cherry, lily of the valley, lilac, raspberry.
Potatoes and Jerusalem artichokes reproduce by tubers - modified underground shoots.
Modified underground shoots also include the rhizome characteristic of lily of the valley, iris, peony and many other plants.
Bulbous plants grow from bulbs - modified underground shoots.

TO vegetative method Reproduction also includes grafting shoots of a plant of one species onto the trunk or stem of another.

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Plant organs are divided into vegetative and generative.

The vegetative organs of plants carry out all the vital processes of the body, with the exception of sexual reproduction, while the generative organs of plants ensure the occurrence of this particular process. The vegetative organs of plants include the root and shoot, and the generative organs of plants include the flower, seed and fruit.

Root - underground vegetative organ plants. With the help of roots, plants absorb water and minerals from the soil, are fixed in it, transport water and minerals to the shoot, accumulate nutrients and can carry out vegetative propagation.

Plant roots are divided into main, lateral and adventitious. The main root originates from the seed embryo, and the adventitious roots extend from the shoot. Lateral roots of plants are formed on the main and subordinate roots. The collection of roots of a plant is called the root system. Depending on the severity of the main root, taproot and fibrous root systems are distinguished. In the first of them the main root is well expressed (carrots, cabbage), in the second there is no predominance of one of the roots (wheat, onions).

On a longitudinal section of a plant root, four zones are distinguished: the growth zone, the suction zone and the lateral root zone, as well as the root cap. Since plants are characterized by open growth, constant cell division and elongation occur in the growth zone. The root cap protects the growth zone from damage by solid soil particles. Its outer cells gradually mucus and slough off, facilitating the movement of the root in the soil.

In the suction zone, water and minerals are absorbed from the soil using root hairs, which increase the surface area. In the zone of lateral roots, transport of mineral substances absorbed by water into the shoot occurs. Here, the deposition of reserve substances and the formation of adventitious buds occur, with the help of which vegetative propagation is possible, for example in dahlias.

Plant organs - roots can enter into symbiosis with nodule bacteria and fungal mycelium, forming mycorrhiza. Nodule bacteria form growths on the roots of legumes and some other plants - nodules, and fix atmospheric nitrogen in a form accessible to plants. Mycorrhizal fungi provide minerals to the plant. In return, bacteria and fungi receive organic substances from plants. Modifications of the root are: roots(carrots, beets, radishes), root tubers (dahlia), supporting roots (ficus banyan), trailing root organs (ivy), respiratory roots (swamp cypress), aerial roots of orchids, etc.

A shoot is an above-ground plant organ consisting of a stem, leaves and buds. Ordinary leafy shoots are called vegetative, and those that also bear flowers or fruits are called generative.

Stem- axial part of the shoot. The stem brings the leaves to the light, supports the generative organs, transports water and substances dissolved in it, reserve substances are deposited in the stem, and it can take part in vegetative propagation. Young stems can perform the function of photosynthesis.

The plant stem is divided into nodes and internodes. At the nodes, leaves and buds are attached to the stem. Leaves can be attached one at a time to a node - this leaf arrangement is called alternate. If there are two leaves at the nodes, then this leaf arrangement is called opposite, and if there are more than two leaves, then this is a whorled leaf arrangement. The part of the stem located between the nodes is called the internode.

The stems are woody and non-woody. A cross section of the stem of a perennial plant shows the bark, represented by the integumentary tissue and underlying cells, phloem, cambium, wood and pith. The bark protects the stem from various types of damage. Lub is a combination of phloem and mechanical tissue, wood is a combination of xylem, mechanical tissue and parenchyma. Cambium is an educational tissue, the cells of which, in the process of division, lay bast cells outward, and wood cells inward.

The core is represented mainly by parenchymal tissue; reserve substances or metabolic products can be deposited in it.

Sheet- organ of aerial nutrition of plants. The main functions of the leaf are photosynthesis, gas exchange, storage of substances and vegetative propagation. The leaf consists of a leaf blade, petiole and stipules. A simple leaf has one leaf blade, while a complex leaf has several leaf blades on one petiole. A cross section shows that the leaf blade is covered with skin or epidermis with a cuticle on top and bottom. The epidermis contains numerous stomata, bounded by two guard cells, between which there is a stomatal fissure. The epidermis may also have hairs. With the help of stomata, hairs and cuticles, the plant regulates the process of water evaporation - transpiration.

The leaf pulp is filled with two types of assimilation tissue. In the upper part of the leaf there is columnar parenchyma, the main function of which is photosynthesis, and in the lower part there is loose or spongy parenchyma, which, in addition to photosynthesis, also carries out gas exchange. The pulp of the leaf is penetrated by veins formed by complexes of conductive and mechanical tissues. The pattern of veins passing through the leaf blade is called venation. Venation can be parallel, arcuate, pinnate, reticulate, etc.

Bud represents a rudimentary shoot. It is covered with kidney scales that protect it from damage. Depending on which shoot rudiment is located in the bud, vegetative and generative buds are distinguished. They are also classified according to their position on the shoot (apical, axillary and lateral buds).

Modifications of the escape are rhizomes(lily of the valley, iris), bulbs (onion, tulip), tubers (potatoes), mustaches (strawberries), etc.

Flower- This is a modified escape. The function of a flower is to ensure sexual reproduction of plants. It consists of a peduncle, receptacle, perianth, stamens and pistil.

The receptacle and peduncle are a modified stem, and all other parts of the flower are derivatives of the leaves. The peduncle attaches the flower to the shoot. All other parts of the flower are attached to the receptacle.
The perianth is divided into a corolla and a calyx. The corolla is formed by petals, and the calyx is formed by sepals. A flower without a perianth is called naked, and one with only a corolla is called corolla, and only a calyx is called calyx.

In the center of the flower there is one or more pistils.
The pistil consists of an ovary, a style and a stigma. Inside the ovary there are one or more ovules containing eggs. The stamen is formed by a filament and anthers held together by a connective tissue. The anther contains pollen grains or pollen. A flower that has both stamens and pistils is called bisexual, a flower that bears only stamens is called male, and a flower that only bears pistils is called female. If there are both male and female flowers on one plant, then such a plant is called monoecious (pumpkin, cucumber), otherwise - dioecious (poplar, sea buckthorn).

For convenience, conventional notations are used in plant taxonomy - formulas and flower diagrams. The flower formula indicates the number of sepals (S), petals (L), stamens (T) and pistils (P). In this case, they take into account whether they are free or fused, and whether the differences between the members of the flower are too great, for example, in the length of the stamens.

Inflorescence called several flowers on one stem. The advantage of an inflorescence is that a large mass of flowers will always be more noticeable to pollinators than a single flower, and the death of one flower in an inflorescence will not lead to the disappearance of the plant's genetic information. Inflorescences are divided into simple and complex. Simple inflorescences include an ear (plantain), an ear (corn), a brush (colza), an earring (birch), a basket (sunflower), a shield (apple tree), a head (clover), an umbrella (onion) and others. Among the complex inflorescences are called a complex spike (wheat), a panicle (oats), a complex umbrella (carrots, dill) and others.

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Basic plant organs

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A plant is a living organism. Each plant - wild, agricultural, garden, indoor - is a complex living organism. Initially, all plants were wild, and man used for himself what they provided in nature. Over time, man selected the most useful plants from nature and cultivated them in order to obtain this or that product in the greatest quantity and best quality. Living plant, especially when in bloom, pleases the human eye. To be able to constantly enjoy the contemplation of living plants, people have become the most beautiful plants grow in rooms. Under the influence of care and special influence, these plants turned into indoor flowers of particular beauty. Each plant, in nature or in a room, requires certain conditions for its existence. The most important of these conditions are moisture, nutrients, air, light, and heat. To use these conditions, the plant has special organs. Thus, the plant extracts moisture and nutrients dissolved in it from the soil with its roots, captures light with its green leaves, and flowers with seeds developing from them are used for reproduction. Root. When a seed germinates, an embryonic root appears, from which the main root develops. A mass of lateral roots extend from the main root, which form the root lobe of the plant. In palm trees, bulbous trees and some other plants grown from seeds, the main root stops growing quite early, and in its place adventitious roots appear from the base of the stem. All plants grown not from seeds, but from plant parts, for example from cuttings, do not have a main root, but only adventitious roots. At the ends of the small roots there are root hairs, through which nutrients are mainly supplied from the soil. The totality of all the roots of a plant is called the root system. By pinching the main root when picking and moderately pruning the roots when replanting the plant, you can enhance the growth of the root lobe. And this will increase the supply of nutrients to the plant. The roots breathe, that is, they absorb oxygen from the air in loose soil, and release carbon dioxide. Therefore, loosening the earth in flower pots and tubs promotes better penetration of air into the soil, and therefore better growth roots and the whole plant. Plant roots are very diverse in shape. Often there are plants (dahlias, asparagus, some types of begonias) with thickened, overgrown roots filled with reserve nutrients. Philodendron, anthurium and some others form aerial roots extending from the stem, which provide support for the stem of the plant. Many perennials capable of producing growth shoots (root suckers) from the roots. Such plants (dracaena, privet, some types of palms, roses) can be propagated by root suckers, dividing the bush, or root cuttings. Stem. The stem connects all the organs of the plant, from the roots to the leaves it carries water with minerals dissolved in it, and from the leaves to the roots, flowers and fruits - the organic substances produced by the leaves, from which the plant builds its body. In most plants the stem is held vertically, but in some it has the ability to twine, climb or cling. Such plants are called lianas. They are widely used for vertical gardening walls, trellises, columns. For this purpose, grapes, creeping ficus, ivy are used in the rooms, and as hanging (hanging) plants - asparagus, tradescantia, chlorophytum. In crinum and cactus, as a result of the accumulation of reserves of nutrients or water, the stem grows in places of accumulation and forms various forms of thickening. Some plants have stems underground that form bulbs (hyacinths, tulips), tubers (begonias, gloxinias), and rhizomes. These modified parts of the stem are not only a place for the accumulation of nutrients, but also a means for plant propagation. Some desert and semi-desert plants, such as most cacti, do not have leaves. In this case, the stem replaces the leaves: it is green and absorbs carbon dioxide from the air. The stems of butcher's broom (ruscus) are modified so much that they resemble leaves. The stem (shoot) contains buds, leaves, flowers and fruits. The bud is a greatly shortened embryonic shoot with embryonic leaves and ends with a growth point. There are growth buds, which have the primordia of shoots and leaves, and flower buds, which bear the primordia of a flower or inflorescence. Flower buds are usually larger than growth buds and more rounded. A growth bud before blooming is called dormant. Some of the buds, usually located in the lower part of the stem, do not bloom for a long time, sometimes for many years, but retain the ability to germinate. Such buds are called dormant. Adventitious growth buds can appear throughout the stem, usually between wood and bark, on roots or wound sites. Dormant, dormant and adventitious buds can germinate when the stems are pruned or damaged. This is widely used to form the crown, to restore lost branches or the entire above-ground part of the plant, to replace outdated parts with young ones (rejuvenation). Sheet. The importance of the leaf for the life of the plant is enormous. The leaves contain a green substance - chlorophyll. In the chlorophyll grains of leaves, organic substances are created from carbon dioxide, water and mineral salts in the light, from which the plant builds its body. This process is called photosynthesis. It occurs only in the light and is accompanied by the release of oxygen. But leaves not only absorb carbon dioxide and release oxygen. In the process of breathing, they release carbon dioxide and absorb oxygen from the air. During the day accumulation processes organic matter prevail over breathing, at night - vice versa. Therefore, during the day, plants improve the air in the room, enriching it with oxygen. The absorption and release of carbon dioxide and oxygen occurs through tiny openings - stomata, which are often located on the underside of the leaf. Water evaporates through them, which facilitates the flow of nutrients from the soil through the roots and their movement throughout the plant. The evaporation of water also protects plants from overheating. Therefore, it is very important that the leaves are always clean and sufficiently illuminated by sunlight, preferably diffused light. Many plants have beautiful leaves and are grown indoors for this reason. Flower. The main purpose of a flower is to produce seeds and fruits. But indoor plants They rarely reproduce by seeds, and the flowers here serve mainly as decoration. Because of the beauty of the flowers, the plants are grown indoors. Flowers are located on the plant either singly, ending in a shoot (tulip, etc.), or in groups in a certain order. These groups are called inflorescences. Majority ornamental plants forms inflorescences of various shapes and structures. Flowers come in various sizes, shapes and colors. The flowers of roses, camellias, and cacti are extremely diverse and exceptionally beautiful; Other plants have uniquely beautiful inflorescences and buds. The doubleness of a flower (increased number of petals), along with color and aroma, is an extremely valuable property of ornamental plants, and double flowers are valued significantly higher than simple (non-double) ones. Roses, camellias, rosanas, lilacs and many other plants have double flowers. Time and duration of flowering have great value. During periods unfavorable for flowering (autumn, winter, and open ground and spring), every color is dear. The ability to bloom during such a colorless period alone is a valuable property of a particular plant. Knowing the time and duration of flowering, you can select plants so as to have flowering specimens almost all the time. Plants usually bloom once a year, but there are also plants that bloom twice or several times annually. These plants are called remontant (certain groups of roses, lemons, etc.). The duration of flowering is significantly influenced by nutrition, humidity, heat, air and light. An abundance of light and moisture, for example, increases the duration of flowering in many plants. In most plants, the formation of seeds causes the cessation of flowering, so removing the ovaries helps to extend the flowering period. Not only flowers, but often also fruits decorate the plant. The rooms contain many plants with beautiful fruits (citrus, nightshade, fruit).

Each plant, in nature or in a room, requires certain conditions for its existence. The most important of these conditions are moisture, nutrients, air, light, and heat. To use these conditions, the plant has special organs. Thus, the plant extracts moisture and nutrients dissolved in it from the soil with its roots, captures light with its green leaves, and flowers with seeds developing from them are used for reproduction.

Root. When a seed germinates, an embryonic root appears, from which the main root develops. A mass of lateral roots extend from the main root, which form the root lobe of the plant. In palm trees, bulbous trees and some other plants grown from seeds, the main root stops growing quite early, and in its place adventitious roots appear from the base of the stem. All plants grown not from seeds, but from plant parts, for example from cuttings, do not have a main root, but only adventitious roots. At the ends of the small roots there are root hairs, through which nutrients are mainly supplied from the soil. The totality of all the roots of a plant is called the root system. By pinching the main root when picking and moderately pruning the roots when replanting the plant, you can enhance the growth of the root lobe. And this will increase the supply of nutrients to the plant. The roots breathe, that is, they absorb oxygen from the air in the loose soil and release carbon dioxide. Therefore, loosening the soil in flower pots and tubs promotes better penetration of air into the soil, and consequently, better growth of the roots and the entire plant.

Plant roots are very diverse in shape. Often there are plants (dahlias, asparagus, some types of begonias) with thickened, overgrown roots filled with reserve nutrients. Philodendron, anthurium and some others form aerial roots extending from the stem, which provide support for the stem of the plant. Many perennial plants are capable of producing growth shoots (root suckers) from their roots. Such plants (dracaena, privet, some types of palms, roses) can be propagated by root suckers, dividing the bush, or root cuttings.

Stem. The stem connects all the organs of the plant, from the roots to the leaves it carries water with minerals dissolved in it, and from the leaves to the roots, flowers and fruits - the organic substances produced by the leaves, from which the plant builds its body. In most plants the stem is held vertically, but in some it has the ability to twine, climb or cling. Such plants are called lianas. They are widely used for vertical gardening of walls, trellises, and columns. For this purpose, grapes, creeping ficus, ivy are used in the rooms, and as hanging (hanging) plants - asparagus, tradescantia, chlorophytum. In crinum and cactus, as a result of the accumulation of reserves of nutrients or water, the stem grows in places of accumulation and forms various forms of thickening. Some plants have stems underground that form bulbs (hyacinths, tulips), tubers (begonias, gloxinias), and rhizomes.

These modified parts of the stem are not only a place for the accumulation of nutrients, but also a means for plant propagation.

Some desert and semi-desert plants, such as most cacti, do not have leaves. In this case, the stem replaces the leaves: it is green and absorbs carbon dioxide from the air. The stems of butcher's broom (ruscus) are modified so much that they resemble leaves. The stem (shoot) contains buds, leaves, flowers and fruits.

Bud It is a greatly shortened rudimentary shoot with rudimentary leaves and ends with a growth point. There are growth buds, which have the primordia of shoots and leaves, and flower buds, which bear the primordia of a flower or inflorescence. Flower buds are usually larger than growth buds and more rounded.

A growth bud before blooming is called dormant. Some of the buds, usually located in the lower part of the stem, do not bloom for a long time, sometimes for many years, but retain the ability to germinate. Such buds are called dormant. Adventitious growth buds can appear throughout the stem, usually between wood and bark, on roots or wound sites. Dormant, dormant and adventitious buds can germinate when the stems are pruned or damaged. This is widely used to form the crown, to restore lost branches or the entire above-ground part of the plant, to replace outdated parts with young ones (rejuvenation).

Sheet. The importance of the leaf for the life of the plant is enormous. The leaves contain a green substance - chlorophyll. In the chlorophyll grains of leaves, organic substances are created from carbon dioxide, water and mineral salts in the light, from which the plant builds its body. This process is called photosynthesis. It occurs only in the light and is accompanied by the release of oxygen. But leaves not only absorb carbon dioxide and release oxygen. In the process of breathing, they release carbon dioxide and absorb oxygen from the air. During the day, the processes of accumulation of organic substances prevail over respiration, at night - vice versa. Therefore, during the day, plants improve the air in the room, enriching it with oxygen.

The absorption and release of carbon dioxide and oxygen occurs through tiny openings - stomata, which are often located on the underside of the leaf. Water evaporates through them, which facilitates the flow of nutrients from the soil through the roots and their movement throughout the plant. The evaporation of water also protects plants from overheating. Therefore, it is very important that the leaves are always clean and sufficiently illuminated by sunlight, preferably diffused light.

Many plants have beautiful leaves and are grown indoors for this reason.

Flower. The main purpose of a flower is to produce seeds and fruits. But indoor plants rarely reproduce by seeds, and the flowers here serve mainly as decoration. Because of the beauty of the flowers, the plants are grown indoors.

Flowers are located on the plant either singly, ending in a shoot (tulip, etc.), or in groups in a certain order. These groups are called inflorescences. Most ornamental plants form inflorescences of various shapes and structures. Flowers come in various sizes, shapes and colors. The flowers of roses, camellias, and cacti are extremely diverse and exceptionally beautiful; Other plants have uniquely beautiful inflorescences and buds.

The doubleness of a flower (increased number of petals), along with color and aroma, is an extremely valuable property of ornamental plants, and double flowers are valued significantly higher than simple (non-double) ones. Roses, camellias, rosanas, lilacs and many other plants have double flowers.

The timing and duration of flowering are of great importance. During periods unfavorable for flowering (autumn, winter, and in open ground in spring), each flower is expensive. The ability to bloom during such a colorless period alone is a valuable property of a particular plant. Knowing the time and duration of flowering, you can select plants so as to have flowering specimens almost all the time.

Plants usually bloom once a year, but there are also plants that bloom twice or several times annually. These plants are called remontant (certain groups of roses, lemons, etc.). The duration of flowering is significantly influenced by nutrition, humidity, heat, air and light. An abundance of light and moisture, for example, increases the duration of flowering in many plants. In most plants, the formation of seeds causes the cessation of flowering, so removing the ovaries helps to extend the flowering period. Not only flowers, but often also fruits decorate the plant. The rooms contain many plants with beautiful fruits (citrus, nightshade, fruit).

Plant organs: their functions, structure and metamorphoses.

Root and root systems. Root metamorphosis.
Stem and shoot. Metamorphoses of the shoot.
Leaf and its metamorphoses.

1.Root and root systems. Root metamorphosis.

Plant organs that serve to maintain the individual life of the plant (root, stem, leaf) are called vegetative. They are in their infancy in every seed.

Generative organs ensure the process of sexual reproduction. A flower is a modified unbranched shoot with limited growth, adapted for sexual reproduction with subsequent formation of seeds and fruit. Flower organs are modified leaves: integumentary leaves form sepals and petals, and spore-forming leaves give rise to stamens and pistils. The structural features of the flower are related to the methods of pollination.

Metamorphoses of vegetative organs.

The main vegetative organs of a plant are the root, stem and leaf. In addition to typical vegetative organs, there are often modifications of them that arose during the long process of evolution. These phenomena are otherwise called metamorphosis, which means transformation. Modified organs are sometimes so unique that their origin cannot be immediately determined.

Sometimes the shape of a particular plant organ (for example, a beet root) changes as a result of human activity.

Root morphology and root systems.

The root is a specialized organ of soil nutrition. It performs the following functions:

absorbs water and mineral elements

serves for fixation in the soil;

has motor activity (stretch zone);

may also have reserve functions, taking the form of root tubers (dahlia);

the fulfillment of new functions leads to the emergence of: a) respiratory roots in marsh plants; b) roots - trailers (ivy); c) aerial roots of orchids and other modifications.

But the main function of the root is soil nutrition. This function determines the peculiarity of the structure. Firstly, the root must have as large a surface of contact with soil particles as possible and grow tightly together with them. Secondly, the suction working areas of the root cannot remain in place - they must move, exploring new spaces and overcoming the resistance of dense soil.

Movement in dense soil is made possible by apical root growth and protective devices that allow the delicate apical meristem to push through between soil particles.

The suction fabric performs the most important function roots - soil nutrition. It consists of a single layer of cells located on the surface of the young root. The entire outer layer of cells covering the young root is called rhizoderm.

The cells of the suction layer have thin membranes and fit tightly to the soil particles. They actively influence the soil and absorb the necessary substances. This activity requires significant energy expenditure, which is ensured, firstly, by a constant influx of organic substances and, secondly, by the intense oxidation of these substances, i.e. breathing with oxygen consumption. Therefore, the system of intercellular spaces filled with gases and facilitating gas exchange is fundamentally well developed.

The cells of the suction layer form long outgrowths - root hairs, which increase the surface of the root several times.

Root hairs appear only at some distance from the root. This is explained by the fact that the area of the root between the hairs and the sheath experiences strong stretching and slides between the soil particles. Any irregularities and protrusions in this area of the root would make it difficult to penetrate the soil.

The first root to appear when a seed germinates is the main root, which develops from the embryonic root. The main root is a first order axis. Lateral roots extend from it, these are second-order axes, third-order roots come from them, etc. As a result, a root system is formed.

On plants, adventitious roots often form from stems or leaves. Their structure and functions are the same as those of the main and lateral roots.

Since the stem is thicker than the root, the boundary between them is usually noticeable. The junction of the stem and the root is called the root collar, and the section of the stem located between the root collar and the cotyledons is called the hypocotyl, or subcotyledon. Adventitious roots often arise from it. Their formation is facilitated by hilling of plants. Due to adventitious roots, the root system increases, which improves the nutrition of the plant and makes it more stable.

The root system can be taproot if the main root stands out among other roots due to its size, and fibrous if the main root is poorly developed and does not differ from the other roots.

The shape of tap roots is: cone-shaped (parsley); turnips (turnips, beets); filamentous (flax sprouts); fusiform (some varieties of carrots).

The length of the roots varies widely. In cultivated cereals, the main mass of them develops in the arable horizon, but individual roots will fall to a depth of 1.5 - 2 m.

The total length of the roots of one rye or wheat plant (without root hairs), grown in the field, is 600 m - 70 km.

There are growing and sucking roots. The first one grows quickly, soon becomes covered with a plug and does not absorb water. Sucking plants grow slowly, remain tender for a long time and absorb soil solutions well. They are the endings of roots of higher orders.

Metamorphoses of roots.

The root crop is formed from the main root due to the deposition of a large amount of nutrients in it. Root crops are formed mainly under conditions of cultural cultivation of plants. They are found in beets, carrots, radishes, etc. In a root crop, they are distinguished: a) a head bearing a rosette of leaves; b) neck – middle part; c) the root itself, from which the lateral roots extend.

Root tubers, or root cones, are fleshy condensations of lateral as well as adventitious roots. Sometimes they reach a very large size and are a receptacle for reserve substances, mainly carbohydrates. In the root tubers of chistyacha, orchids, starch serves as a reserve substance. Inulin accumulates in the adventitious roots of dahlias, which have turned into root tubers.

Among the cultivated plants, the sweet potato belongs to the bindweed family. Its root tubers usually reach 2 - 3 kg, but can be larger. Cultivated in subtropical and tropical areas to produce starch and sugar.

Aerial roots are formed in some tropical plants. They develop as adventitious stems, are brown in color and hang freely in the air. Characterized by the ability to absorb atmospheric moisture. They can be seen in orchids.

Clinging roots, with the help of which weak vine stems rise up tree trunks, along walls, slopes. Such adventitious roots, growing into cracks, secure the plant well and give it the opportunity to climb greater height. This group of vines includes ivy, which is widespread in the Crimea and the Caucasus.

Breathing roots. Swamp plants, to which air access to ordinary roots is very difficult, grow special roots directed upward from the ground. They are located above water and receive air from the atmosphere. Swamp cypress has breathing roots. (Caucasus, Florida).

Organs are similar and homologous.

Charles Darwin introduced the concept of analogous and homologous organs.

Similar organs perform the same functions, but have different origins (hawthorn spines and cactus spines).

Homologous organs - have the same origin, but perform different functions. (Pear thorn, kupena rhizome).

Class: 1

Teacher: Kaysarimova R.M.

Lesson topic: “Plant organs and their functions.”

Lesson Objectives : Form an idea of the structure of plants, find out the significance of each part of the plant;

generalize and systematize students’ knowledge about a plant as a living organism; about plant diversity;

develop communication and information competence, the ability to identify essential features; install cause-and-effect connections, ability to generalize, draw conclusions;

cultivate a caring attitude towards plants.

Lesson type: learning new knowledge

Methods: partially exploratory, practical, creative

Shapes: collective, group, individual

Equipment : presentation, illustrations of plants, test tasks, students sit in groups.

Progress of the lesson.

1. Motivational - target stage.

The bell rang and class began.

Hello guys. Sit down.

Hold hands and wish each other good work.

Now let's solve the crossword puzzle and read the keyword.

Crossword “Plants” (slide1)

1. It’s not fire, it burns. (Nettle. )

2. Little red nesting doll, little white heart. (Raspberry .)

3. What kind of tree stands -

There is no wind, but the leaf is trembling. (Aspen .)

4. The last smile of autumn.

Star in the flowerbed (Aster. )

5. Sticky buds, green leaves.

With white bark, they grow under the mountain. (Birch. )

6. The branch in the bunch is dressed up

Violet color.

It's on a hot summer day,

Blossomed in the garden…….. (lilac. )

7. Takes from my flower

The bee has the most delicious honey. (Linden .)

8. I lost my dress

The buttons remain. (Rowan .)

What is a plant?

Plant - These are the bodies of living nature. On Earth there are a wide variety of plants by type, height, and age.

Why are plants considered living organisms? List the signs?(clied2)

Plant

What does a plant need for growth and development? (slide 3)

What groups are plants divided into? (slide4)

Plants

Well done.

A student reads a poem.

“ We collected hot poppies in a bouquet,

Lots of blue forget-me-nots.

And then we felt sorry for the flowers,

They were planted in the ground again.

But nothing works:

They sway from any breeze!

Why did they crumble and wither?

Help us figure it out."

Why do plants wither? Explain?

Name the topic of our lesson.

2. Operational stage.

Each group is given a task.

When preparing, each group can use a textbook.

1 group. Look carefully at the pictures of plants. Connect their identical parts. Remember what they are called. Prepare a speech on the topic “Parts of Plants”

2nd group . Look at the plant on the card. Attach the labels with the names of plant parts in their places. Prepare a speech on the topic “Why do plants need these parts?”

3rd group. Consider individual parts of plants. Name them. Fold in such a sequence that you get a whole plant. Prepare an answer to the question “What do different plants have in common?” ”

Fizminutka

The wind is blowing in our faces.

The tree swayed.

The wind is getting quieter and quieter.

The tree is getting higher and higher.

- Now each group will present their performance.

Group performance.

Formative assessment of groups “Tsvetik-Semitsvetik”

Great - big flower

Good - average

Not very - small

Model answer #1

Model answer #2

Model answer #3

What parts does a plant consist of?

What conclusion can we draw?

Conclusion: all plants have the same structure: root, trunk, leaf, flower, fruit.

What importance do plants have in human life?

Well done.

3. Control and evaluation stage.

Now we will check how you understood the new material.

Everyone has a test with tasks on their desk.

Run the test.

1. Which part strengthens the plant.

a) stem b) *root c) leaf

2. What is formed in place of the flower.

a) * fruit b) stem c) leaf

3.Which part is responsible for plant respiration.

a) stem b) root c) *leaf

4. What is inside the fruit..

a) flower b) *seeds c) leaf

5. What is the difference between a tree and a bush.

a) * it has one trunk b) stem c) many trunks

Checking the test.

Formative assessment.

Rate yourself on a five-point scale.

4. D/Z: draw describe the plant.

5. Reflection.

What did you learn that was useful for you in class today?

Will this knowledge be useful to you in life?

Have you expanded your knowledge base?

Did you enjoy the lesson?

The lesson is over.