The stalk is part of the plant, which is above the ground. It has a round or cylindrical shape. Grows during one growing period.

Depending on the location of the leaves, the stem is divided into nodes and interstices. The node is a place where the sheet is attached to the stalk, and the interstice is the distance between the two nodes.

Depending on plants, the stems may have a greater or less branches covered with bark, soft or solid, thick or thin, straight or curly, climbing or creeping, juicy, green. If you cut up the top in the plant, then it will branch. The stem is a support and a transport artery that delivers water and nutrients To leaves and flowers from the roots and back. Stem and root stock and stored nutrients. Upper green parts of young stems are involved in the process of photosynthesis. Later, they clarify, and cannot take part in photosynthesis.

Using the stem, it is possible to carry out vegetative reproduction. The flexibility of the stem allows the plant to bend, rotate to choose for the leaves the most optimal light mode.

Sheet is a green plant organ that is one of the important. Developed on the stem. The leaf cleans the air, is responsible for the processes of photosynthesis and gas exchange, evaporates moisture through its surface, as a result of which the plant is cooled.

As a rule, the leaves are flat, green, which contributes to the enhanced absorption of sunlight, which is necessary for the photosynthesis process. In most plants, the leaves consist of a plate, which is dissected by veins, and a stuff that attaches a sheet to a stalk. There may be no petiole in some leaves. Such leaves are called sedent. The location of the leaves on the stem may be in the following order: In the next - only one sheet is in the stroke node; The opposite - the leaves are located opposite each other, mutter - several leaves are in one stroke node.

The leaves are inherent in many shapes, sizes and paintings. Out of the form of the leaves are remover, oval, rounded, lanceal, solid or dissected and fan-shaped. In size, the leaves are large, up to several meters, medium or very small, flat. Some plants have modified leaves: Succulents are thick and fleshy, and cacti in the form of barns. The color of the leaves can be monophonic or motley and includes a large coloring gamut.

The flower is responsible for the continuation of the kind, and is usually a beautiful part of the plant. The flower includes breeding organs: female seed and male pollen.

Flowers consist of petals, couples, pestle and stamens. The color of the flower is associated with the process of reproduction. Insects are attracted by bright color, and when they sit on the flower to their paws sticks to the pollen, which they carry on the pestle. Thus, the process of fertilization occurs. Flowers that do not have a bright color attract insects a pleasant or repulsive aroma. Also, pollen can be transferred with wind from one plant to another.

There are routine flowers - these are those who have male and female breeding bodies, and same-salts - who have only stamens or only pestles. Plants are one-bedroom - these are those that form on one plant and men's and women's flowers, and dwarfists - they have different floors on different flowers.

Flowers collected in the group are inflorescences. Inflorescences are in the form of brushes, cobs, umbrellas, baskets, shields and sections. Seeds in plants appear after fertilization.

Artificially extend flowering, you can break off the plants of the ridiculous fertilized flowers.

After the flower is fertilized, seed develops in it. The seed consists of peel and the embryo, in which a new plant is formed, as well as from the reserve of organic and minerals, from the water. All these components first nourish the embryo.

Seeds are of different sizes: very large and microscopically small, and they are born in different numbers. The formation of the fetus occurs with the development of seed. Fluity function - protect and distribute seeds.

Seeds can be transferred to animals, wind, birds, water, people. If the seed applies to the wind, then it is usually small, lung, has wings or small hairs. Seeds that are distributed by pets, bright and tasty, are absorbed by them and exit through an excretory or digestive system.

For proper storage Some seeds can be stored long enough, while others can exist only phase. What would the seed sprout need to perform a number of conditions: the seed should have a living germ, favorable temperature, moisturized soil, as well as air access.

Seeds at home are practically not formed due to the fact that there is no fertilization and there are no favorable conditions for fetal aging. The owners themselves can conduct fertilization with a soft tassel, as well as try to grow fruits.

Root - as a rule, it is an underground part of the plant. The root performs such functions: holds a plant in the soil; It absorbs water and useful substances from soil and recalculates them on a stalk to leaves and flowers; accumulates spare substances; participates in the process of breathing; It highlights the decomposition of substances in the soil.

W. different plants The number of roots is different. The development of roots depends on the environment. Root system is the roots of the plant. The root system can be from several centimeters to several meters. Some plants, such as orchids, roots can be above the ground. And, for example, Ivy, cling to its roots to the support.

Plants, from tropical deserts, have roots, which are located close to the surface of the soil, which allows to absorb water in the form of precipitation. Plants with swampy places to provide air access, have their roots over the water. Such plants are called respiratory.

Roots can be in the form of bulbs, thickened roots or tubers.

Plants are called photosynthesizing living organisms related to eukaryotes. They have a cellular cellulose shell, a spare nutrient in the form of starch, sediments or stationary and grow throughout life. The chlorophyll's pigment contained in them gives the green color plants. In the light out of carbon dioxide and water they create organic substances And the oxygen is isolated, thereby ensuring the power and breathing of all other living organisms. Plants also have regenerating ability, can restore vegetative organs.

Science, studying the structure and vital activity of plants, their systematics, ecology and distribution, is called botanica(from Greek. Botane - Grass, Greens and Logos - Teaching).

Plants constitute the bulk of the biosphere, forming the green cover of the Earth. They live in different conditions - water, soil, ground-air environment, occupy the whole land of our planet, with the exception of the Arctic and Antarctic icy deserts. Life forms Plants. Trees are characterized by the presence of a webly stem - trunk, which remains throughout life. Shrubs have several small trunks. For herbs are characteristic of juicy, green, non-devented shoots. Life expectancy.Distinguished annuals, twilight, perennial plants. Trees and shrubs belong to perennial plants, and herbs can be both perennial and annual and twilight. Structure of plants.The body of plants is usually disseminated on rootand the escape.From higher plants the most highly organized, numerous and distributed are flower plants. In addition to root and escape, they have flowers and fruits - organs that are absent from other groups of plants. The structure of plants is convenient to consider on the example of flowering plants. Vegetative plant organs, root and escape, ensure their nutrition, growth and useless reproduction.

Types of root systems: 1 - rod; 2 - urine; 3 - cone-shaped rootproof parsley; 4 - the reinproved beet; 5 - Root cones dahlia
With () root, the plant is fixed in the soil. It also provides water and mineral and mineral substances and often serves as a place of synthesis and supply of nutrients. Roots begin to form already in the enormous plant. In germination of seed from the germinal roaster formed the main root.After some time, numerous many side roots.A number of plants from stalks and leaves are formed pressure roots. The totality of all roots is called root system.Root system can be rod,with well-developed main root (dandelion, radishes, apple tree) or urineformed side and apparent roots (barley, wheat, onions). The main root in such systems is weakly developed or is completely absent. A number of plants are in rooted nutrients (starch, sugar), for example, in carrots, turnips, beets. Such modifications of the main root call roots.In dahlia, nutrients are deposited in thickened pressing roots, they are called cornklubei.There are in nature and other radiation modifications: root trains(Lian, Ivy), air roots(at Montster, Orchids), walker roots(in mangrove plants - Banyan), respiratory roots(in marsh plants). Grows the root of the top where the cells are educational fabric - growth point.She is protected root case. Root hairssuck water with mineral substances dissolved in it suction zone.By conductive systemroot water and minerals come up to stems and leaves, and down organic substances are moving down.

The escape - This is a complex vegetative organ consisting of kidneys, stem and leaves. Along with vegetative, flower plants have generative shoots on which flowers are developing.

Escape is formed from the germinal kidney seed. Development of shoots of perennial plants from the kidneys is well noticeable in spring. By the location of the kidneys on the stem distinguish topand side kidneys.The top kidney provides the growth of escape in length, and the side is its branching. The kidney is covered with dense scales, often impregnated with resinous substances, inside are the desired escape with a cone of the rise and leaves. In the sinuses of the embossed leaves there are barely noticeable embossed kidneys. In the generative kidney there are routines of flowers.

Stem - This is the axial part of the escape on which leaves and kidneys are located. It performs a reference function in the plant, provides the movement of water and minerals from the root up to the leaves, organic substances down, from the leaves to the root.

Externally, the stems are very diverse: in corn, sunflower, birch - reprehension; In Pyrey, the laptops are creeping; At Vuska, hops - curly; Pea, Liana, grapes - Lyezing. The internal structure of the stem is different in monocotyled and dietary plants ().



The internal structure of the stem. Transverse section: 1 - stem corn (vascular bundles are located all over stalk); 2 - Linden branches
1. W. divine Plantstem outside covered with skin - epidermaperennial weighted stems of the skin is replaced cork.Under the tube there is a Louba formed by the sieve tubes that ensure the movement of organic substances by stalk. Lubyanny mechanical fibers give stall strength. Cork and Lub form cora. To the center from the Luba is cambium - Single layer of cells of educational fabric, ensuring the growth of the stem in thickness. Under it is located woodwith vessels and mechanical fibers. Visa moves water and mineral salts, And the fibers give the wood strength. When growing wood formed annual ringsfor which the age of wood is determined. In the center of the stem is located core.It performs a sparkling function, organic substances are deposited in it. 2. W. monocoan plants the stem is not divided into a bark, wood and core, the cambial ring is missing. Conductive beams consisting of vessels and synoid tubes are evenly located all over the stalk. For example, cereals are sulp - Solmin, inside the hollow, and the conductive beams are located along the periphery. In a number of plants there are modified stems: spines of hawthorn, employees for protection; Ugings in grapes - to attach to the support.

Sheet - This is an important vegetative organ plant that performs the main functions: photosynthesis, water evaporation and gas exchange.

The plants distinguish several types of light positions: anotherwhen the leaves are arranged alternately after each other, opposite - Leaves are located opposite each other and mutovskaya - Three and more leaf depart from one node ().

List position: 1 - next; 2 - opposite; 3 - mutter
The sheet consists of sheet plateand stuffsometimes there are horses. The leaves without a petiole call sitting.In some plants (cereals), non-cemeted leaves form a tube - the vagina, clambering the stem. Such leaves are called vaginal().



Types of leaves (a): 1-cylinder; 2 - sedentary; 3 - vaginal; Leaf housing (b): 1 - parallel; 2 - arc; 3 - Mesh
Leaves can be simple and complex. Simple sheethas one sheet plate, and complicated - Several sheet plates located on one cut ().

Leaves Simple: 1 - linear; 2 - Lancing; 3 - elliptical; 4 - egglike; 5 - heart-shaped; 6 - rounded; 7 - sweat-shaped; Complex: 8 - parsley; 9 - unparallers; 10 - Troy; 11 - Palcounty
A varied forms of leafy plates. At ordinary leaves, leaf plates can be solid and dissected with different edges: toothed, sawmakers, gorgeous, wavy. Complex leaves can be pair and nonpopristembudd, palc clutches, troops. The leaf plate is system residentsperforming reference and transport functions. There are mesh housing (in most disadvantaged plants), parallel (cereals, sources) and arc (lily of the valley) (see). The internal structure of the sheet (). Outside sheet covered epiderma – skinwhich protects the inner parts of the sheet, regulates gas exchange and evaporation of water. Skin cells are colorless. On the surface of the sheet there may be peel cells in the form of hairs. Their functions are different. Some protect the plant from eating animals, others - from overheating. The leaves of some plants are covered with a wax, poorly skipping moisture. This helps to reduce water loss from the surface of the leaves.



The internal structure of the sheet: 1 - skin; 2 - Ustian; 3 - columnar fabric; 4 - spongy fabric; 5 - Liva resident
On the underside of the sheet in most plants in the epidermome are numerous ustian - Holes formed by two closing cells. Through them are carried out gas exchange, evaporation of water. In the afternoon, the ustical gap is open, and closes overnight. The inside of the sheet is formed by the main assimilant clothproviding the process of photosynthesis. It consists of two types of green cells - columnslocated vertically, and rounded, loose spongy.They contain a large number of chloroplasts, which give the green color sheet. The pulp of the leaf is permeated by residents formed by conducting vessels and sieve tubes, as well as fibers that attach strength. In the veils, organic substances synthesized in the sheet move to the stalk and roots, and the flow of water and mineral substances is back. In our latitudes, there is a mass discount of foliage annually - leaf fall.This phenomenon has an important adaptive importance, it protects the plant from dried, freezing, prevents breakdown of tree branches. In addition, a plant is exempt with dead leaves from unnecessary and harmful substances for it. Many plants have modified leaves performing specific functions. The pea mustache, clinging to the support, support the stem, nutrients are spinning in scaly leafs, barberry spines protect it from eating, Rosyanka traps lure and catch insects. Most perennials herbatous plants occurs modiation of shoots,which adapted to perform a variety of functions ().

Separations of shoots: 1 - rhizome purchases; 2 - onion bulb; 3 - Potato Tubat
Rhizome - This is a modified underground escapeperforming the functions of the root, as well as serving the supply of nutrients and vegetative reproduction of plants. Unlike the root, the rhizome has scales - modified leaves and kidneys, it grows horizontally in the ground. The apparent roots grow from it. The rhizome is available at the valley, the sources, bought, crawling ramp. The strawberries are formed overhead modified collisions - mustache, providing vegetative reproduction. When contacting the ground, they are rooted with the help of apparent roots and form a rosette of the leaves. Underground Stokers - Potato Potatoes - it is also valid shoots. In a well-developed core of their strongly thickened stem, nutrients are stored. On the tubers you can see the eyes - the kidneys located on the spirals, of which the above-ground shoots are developing. The bulb is a shortened escape with juicy leaves. The lower part - the Donets is a shortened stem, from which the apparent roots grow. The bulb is formed in many Lily (tulip, lilies, daffodils). Modified shoots are served for vegetative reproduction of plants.

The flow of water through the root system is reduced with a decrease in temperature. This happens for the following reasons: 1) the viscosity of water increases, and therefore its mobility is reduced; 2) decreases the permeability of the water protoplasm; 3) inhibits the growth of the roots; 4) The speed of metabolic processes decreases. Water flow decreases with a deterioration in soil aeration. It can be observed when after a heavy rain soil flooded with water, but with bright sun due to strong evaporation of

shades come up. The concentration of soil mortar is of great importance. Water enters the root only when the water potential of the root is less than the water potential of the soil. If the soil solution has a more negative potential, water will not flow into the root, but to leave it.

For normal functioning, plant cells must be saturated with water. The saturation state is supported using two interrelated processes: the receipts and isolation (spending) of water, which constitute water exchanging plants. The ratio between these processes is called water balance.

The plant highlights water in liquid and vapor states. The physiological process of evaporation of water by terrestrial plants received, as already noted, the name of the transpiration, the release of water in the drop-head state - the guilders.

Life originated in the World Ocean. With the output of plants, the danger of their death from drying appeared. Why? The concentration of water vapor in the air, even in the conditions of a wet climate, is always less than in the interclauses of the sheet, therefore, the water from the body of the plant inevitably occurs in environmentAt the same time, the diffusion of water molecules from the surface of the sheet into the air occurs 1,500 times faster than their arrival from the soil in the root.

Large water loss by a plant is due to its large leaf surface. One plant of corn spends over the growing season 200 liters of water, and sugar cane is twice as much. Plants are forced to form a large leaf surface to obtain the required amount of CO 2 for photosynthesis, despite its small content (0.045%) in the atmosphere.

For example, an 8-year-old apple tree can assimilate a day to 50 g CO 2 with intense photosynthesis. This amount of CO 2 it absorbs from 300,000 liters of air.

The need to spend water in large quantities is due to the fact that the absorption of sun rays by plants should lead to an increase in temperature, which can cause protein coagulation. Evicious water, the plant lowers the temperature of its body.

For most plants, drying is deadly, so water consumption should relate to the arrival. Only mosses and lichens can withstand a long lack of water and carry this time in a state of drying.

Therefore, as soon as the plants came out of the water to land, a long process began to develop equipment for maintaining water balance: first, for rapid receipt, secondly, to reduce waste by land bodies; Thirdly, for economically favorable transport on a stalk.

When analyzing the relationship between the flow and spending of water, three cases are possible: the receipt of more spending is equal to or less. In the latter case, water deficit occurs. At noon, the water deficit can reach 5-10 and even 25%. One of the conditions for the normal functioning of terrestrial plants is to maintain conditions without a long and deep water deficit. This requires a well-developed root systemproviding water intake at high speed.

The flow of water from the soil to the root. The flow of water from the soil is a more complex process than a simple water absorption by a plant, lowered into any aqueous solution roots. In the soil, we have a number of forces opposing this suction, which can be called water-holding forces.

The soil is a multiphase system consisting of four main components: solid mineral particles, organic matter (humus), soil solution and soil air.

Mineral particles and humus form the soil structure, water and air fill the cavities of this structure.

The ability of the soil to keep water depends on its composition and properties. A certain amount of water is part of the mineral components of the soil and inaccessible to plants (hygroscopic water). A variety of clay minerals and heterogeneous humus substances that are colloids can also hold a significant amount of hydration water. Such water is conditionally referenced (cell) and also difficult to access. Water in soil capillaries (capillary water) is easily absorbed by root hairs and surface cells of the sucking root zone. Such water is considered free.

In addition, in the soil we are dealing with a solution, and not with clean water; Therefore, the solution itself has suspicious power. In equilibrium concentrations in the soil and in the vessels of xylems, in general, water flow should stop.

To calculate the amount of inaccessible soil moisture come as follows. Plants are grown in a vessel with impermeable walls with walls (glass or metallic) and after the plants will develop well, the soil cease to water and leave in a presence prior to planting plants. The building indicates that the delivery of water in the roots ceased. The amount of water that remains in the soil by the time of the sharing, and will be inaccessible to the plant (dead reserve). The amount of inaccessible water received the name of the coefficient of the sharing or moisture content. Consequently, the coefficient of installation characterizes the humidity at which the steady installation is only beginning.

At this point, there are still some amount of water in the soil, although small, but to some extent affordable for the plant. Under these conditions, even a strongly collapsed plant comes to life if it is started to water. Full death occurs only with humidity significantly lower than the coefficient of charge.

Thus, the moisture content is the lower boundary of the humidity interval, in which the growth of the plant is possible.

When water intakes in dry soil, it absorbs very quickly. Then, the rate of seepage of water into the lower horizons becomes slow. When the speed of the downward current of water decreases sharply, the soil moisture is reaches a level called field moisture intensity.

Under the soil moisture available for the plant, there is due to the amount of water that accumulates in the soil from the level of moisture content of stable excretion to field moisture intensity.

Radial vehicles of water.To go to a conversation about the radial transport of water, you must briefly remember the general features of the root structure, (although in the details of the root structure in different types Plants varies).

In both types of plants there is a central cylinder (stele), in which there are vascular bundles and (drainage) parenchyma. With the help of vascular beams (Floem), the relationship between different parts of the plant and places of carbohydrate synthesis are maintained. According to vascular beams (xylem), water and dissolved substances are coming from the root. If you move to the periphery, then the reference is the single-row cell layer. Then the endoderma is also a single-row layer of cells, especially well adapted to serve as a barrier, which separates conductive tissues from the bark. After the stretching of the cells ends, in the radial and transverse shells of the endoderm, the layer of the material is detected, which gives a positive reaction to lignin. This is the so-called cappi belt. Kaspari's belts strongly limit the movement of water, ions in cellular shells. Thus, they effectively block apoplastic transport.

Most of the roots occupy cortex cells. Their share (together with the epidermis) accounts for 86-90% of the area. The cortex cells are stretched parallel to the main axis, the thin layer of cytoplasm (1-5 μm) surrounds the central vacuol, which takes ~ 90% of the protoplast. Secondary changes in the shells of the cortex cage are reduced to the deposition of cellulose; Only some species take offense. In general, the shells retain permeability. They have numerous pores that can be filled depending on air or water conditions.

On the periphery of the root is located epidermis (risodermis). This is the outer fabric of the root consisting of elongated tightly packaged cells. The shells of these cells can over time to undergo changes associated with the deposition of a coutine - water-repellent substance.

External tangential shells of ricodermis cells are able to stretch strongly and form tubular growth, so-called root hairs. Note that cells that can form root hairs are called trichoblasts, and which are not capable of forming - atrichoblasts.

So, the water that fell in the root hairs or other cage of the root using one of the mechanisms we talked about, moves to the vessels of xylems, i.e., there is a radial movement of water along the root tissues.

The movement of water in the root hairs or other cell begins with interaction with the cells of the cells, then water can pass through a plasmamanema and transported from the protoplast of one cell into the protoplast another through plasmodesma. In this case, the water moves along the symplast. However, water could not enter the symplast, but to remain in the cell shell and move along the root tissue to the central cylinder. This is an apoplastic path. But on Apoplast, water can only move to the endoderma (to the Kaspari belt). Therefore, the path of water on Apoplast ceases here. For further movement, it must necessarily enter the symplast.

The first barrier function of the endoderma revealed D. Prious in 1920. Recently, this feature has been repeatedly confirmed.

The need to switch the movement of water with apoplast to the symptorate path is of great importance, since the process of movement according to the live protoplasm of the cell itself can be adjusted in contrast to the movement of water through the cell walls.

For the flow of water to the root, it is necessary that the aqueous potential of ricoderms is less than the aqueous potential of the soil solution; In this case, the water will start flowing into the cells.

The soil can be considered as a reservoir, the amount of water in which it increases, then decreases. If after the rain the soil is in a state of field moisture, then its water potential is close to zero; Water easily enters the roots. As the soil drying, its water potential decreases.

The water potential is maximum in the soil, somewhat smaller in the root cells and the lowest in the cells adjacent to the leaf epidermis.

The first cause of the occurrence of the water potential gradient is the active flow of salts and their active movement from one cell to another. The second - living cells of the parenchyma of the central cylinder are distinguished by soluble organic and mineral substances into the vessels and thus maintain a water potential gradient in vessels. By entering the Ksylema vessels, they form a osmotic gradient here.

The chemical potential of water in which these ions are below the water potential in the diluted saline solution of the external environment. Therefore, water should move along the gradient of the chemical potential in the root xylem.

Today, a hypothesis is put forward, which has an experimental basis that the roots have a specialized mechanism for active water pumping (aqueous pump), the work of which does not depend on the arrival of ions.

Indeed, energy is necessary for the flow of water to the root, so this process depends on the speed of the aerobic respiration of the roots - the main source of ATP. Thus, one of the main factors causing the flow of water is O 2. Hence the conditions capable of suppressing breathing dramatically reduce the flow of water. As an example, consider the following phenomenon: heavy rain passed, a lot of water was gathered in a low place, and the plant raises. Why? Excess water in the soil has turned out of it from it, the flow of oxygen into the root is difficult, breathing is suppressed. Immediately there is a braking of water flow into the root system. This example explains why on flooded water soils of the plant develop poorly and even dying.

Flooding leads not only to a decrease in the number of 2, but also to an increase in the concentration of CO 2 in the soil, which damages the membranes of root hairs; There is a decrease in water intake, which is confirmed by the braking of the selection of pages.

The flow of water in the root depends on the temperature of the soil. For example, on cold swampy soils, despite the large amount of water, the plants are lack of water, since at low temperatures breathing is suppressed and the supply of energy roots is disturbed. In these conditions, a xeromorphic structure (small cells, a lot of ducts, etc.) begins to form in these conditions (small cells, which is characteristic of dry places.

The state of the plants in which the water cannot act, despite its large amount in the environment, got a name physiological drought.

Various flutters can also affect water flow, in particular through respiratory suppression.

The need to absorb a large amount of water even in its conditions of its limit, for example, in drought conditions, leads to the fact that the plant forms a huge root system. As a result, the roots penetrate into the soil into a large depth. Wheat The length of the roots reaches 90 cm, in alfalfa - 120 cm. If we assume that the depth of the arable horizon is 20-25 cm, then most of the root system is located below. The size of the root system is characterized not only by the depth of their penetration into the soil. The overall surface is of great importance.

Water in the soil moves very slowly: for the month, it does prepund no longer than 30 cm. Move the tip of the root in the soil is ahead of the movement of water. Thus, not water moves to the root, but the root to water in the process of growth. Growth is the first and most important feature of the roots as an organ absorbing water.

In the arid conditions, the root system is formed 3-4 times large than in wet.

Branching and rapid growth help the root to move to water, but, on the other hand, water - prerequisite Growth. As can be seen no longer on the cell, but at the organizational level, we are faced with an example feedbackwhich underlies the regulatory processes.

As an organ absorbing water, the root owns another important property - positive hydrotropism, it means that, with a lack of water, the growing parts of the roots are strung out on the parties of more wet parts of the soil.

Thus, the root system is a specialized water intake body.

The growth of the roots is usually ahead of the growth of ground bodies. This is a very important feature associated with the fact that the root should provide the need for water formative.

However, the cell of any organ that is not saturated with water can also absorb water as soon as it is shown with it in contact. Therefore, the leaves, especially sipopers, during immersion in water quite vigorously suck it; On the other hand, despite the cuticle, water can flow through the surface of the sheet. It is shown that only dry cuticle is almost impenetrable for water; When wetting, she swells and is done permeable, so leaves moistened with rain or dew can absorb up to 25% of water falling on them. It has practical importance when irrigating plants with sprinkling.

Far vehicles of water.Speaking about moving water on the plant, transport in the tissues of one body, which is called near (radial), and transport between individual bodies, which is called far. Between them there is a significant difference. Middle transport goes on non-specialized tissues, and for far in plants there are special conductive tissues. Thus, the path that water passes from the root hairs to the evaporating cell of the sheet, disintegrates into two parts: various products, structure and physiological features. The first part consists of living cells and has small dimensions (millimeters or millimeters). These are two short plots - one - in the root, from its surface with root hairs to vessels that are in its central cylinder; The second is in a sheet, from vessels that are part of a conductive beam, and evaporating water in intersecting chlorine. The second part of the way is the vessels, tracheids, which are dead tubes. In herbal plants, their length is a few centimeters, and the trees reaches several meters and even tens of meters.

Water and mineral elements are delivered to each cell of the above-ground part of the plant due to the ascending current of xylene. There is also a downward floemic current of solutions from the leaves to the roots. The floemic current directional is formed in the cells of the mesophyll of leaves, where part of the water that came with a xylem current, from the mesophyll cell shells in the flora endings.

Water from the sheet cells and directly from the Vessels of xylems comes into the Floem on an osmotic gradient arising due to the flames accumulated in the cells of the Sugar and other organic compounds formed during photosynthesis.

The downward floem current delivers organic matter to the root fabrics, where they are used in metabolism. In the root of the end of the conductive beams of flora elements, as in the sheet, are located near the elements of xylems, and the water again arrives at the osmotic gradient in the xylem and moves upwards. Thus, there is an exchange of water in the conductive system of roots and leaves (as if a circulation).

Water current on the vessels of xylems leads to the fact that when the stem of some plant is cut at a short distance from the soil after a while from the end of the vessels, the juice is started, which is called Passoral. This phenomenon was called "crying plants".

The strength that raises the mouth up the vessels, called root pressure. Root pressure can be measured if it is mounted on a cut tube to connect with a manometer. The magnitude of the root pressure is inconsistent. IN optimal conditions It is 2-3 bars. Under certain conditions, an equilibrium is achieved between the amount of selected passions and the amount of water received, therefore the root pressure, or the amount of selected passages, can reflect the absorption capacity of the roots. Thus, the active engines of the initial ascending current (root pressure) are living cells that adjacent to the lower end of the conductive plant system are the cells of the roots of the roots - the lower terminal engine of the water flow.

The root pressure mechanism is based on the action of contractile proteins, the function of which is considered to be performed by microfibrils of F-proteins.

To some extent, the proof of active water outlet can serve as a suitable.

However, if the plant did not constantly lose water as a result of transpiration, then the cells of root hairs would quickly be saturated with water, and its receipt ceased. Therefore, one of the reasons for the occurrence of a water gradient is the evaporation of water by the above-ground bodies.

The more intense cells of the leaves evaporate water, the faster it will flow into the cages of roots and faster to transport up the plant. The loss of water molecules in the top of the water column as a result of evaporation causes water to flow along the vessels of xylems up to eliminate the loss. This caused by transpiration movement of water received the name of the transpiration current. He, in turn, causes the flow of water from the soil to the plant the same by the gradient of water potential. Due to the transpiration, the aqueous potential at the top of the plant is lower than at the base.

The active engines of the water current due to transpiration are living cells that adjacent to the top end of the entire system conductive system - sheet parenchyma cells. They were called the upper end motor of the water current.

The mechanism of operation of the upper end motor is simple and based on the following. The atmosphere is usually not saturated with water vapor, therefore it has a negative water potential. With the relative humidity of the air 90% it is 140 bar. In most plants, the water potential of the leaves varies from 1 to 30 bar.

Due to the large difference in water potentials, transpiration occurs. Reducing the amount of water in a parenchymal sheet cell causes a decrease in water activity in it and a decrease in water potential.

The aqueous deficit gradually from the cell to the cell reaches the roots, and the activity of water is reduced in them. In this case, water comes from the soil to the root. Thus, it can be concluded that the movement of water on the plant, as well as entering it into the root, is mainly due to the water potential gradient in the soil-plant system. This gradient will be the more, the more water will lose the cells of the sheet, that is, the stronger transpiration.

Two engines are operating unenochnakovo. On average, the upper end motor develops the force of 10-15 bar and even more, and the lower 2-3 bar. It can be seen that the main role in water exchange belongs to the upper engine. However, with the absence of leaves in the trees in winter and in early spring, or after dry period, the main role in the movement of water is performed by the lower engine. A large role in lifting water on the plant The lower end motor must have in conditions of greater humidity when transpiration is minimal.

For the upper end motor, the energy source is the sun, which means that the radiant energy absorbed by the sheet is used for evaporation.

For the lower end motor - the source of energy breathing. The energy of ATP molecules synthesized during the breathing of the root cells is spent on the transport of ions in the cell, that is, on the creation of a water gradient. The regulatory role of the root pressure in the water exchange of plants is schematically represented in Fig. 4.12.

Thus, the upper end motor is an automatically working mechanism that the stronger suits water than faster it consumes.

The work of the upper and lower end engines can easily explain the rise of water for several tens of centimeters, let meter. And how to explain the water raising for tens of meters, and sequoia reaches a height of 140 meters? The vessels along which water moves to most of their path, are dead tubes. They cannot develop forces to raise water. Answer the clutch theory, which was offered by the English researcher in Dixon in 1921, helps to answer this question. In accordance with this theory, continuous threads are formed in vessels, passing from the root parenchyma cells to the cells of the leaves parenchyma. The force that causes water molecules to go over each other, it was named clutch force (cohesion). Continuous water threads are formed due to hydrogen bonds. However, water threads are clicked and with the walls of vessels (adhesion) with a force of 300-350 bar. All this allows lower and upper end engines to raise water on the trunk to a height of 140 m.

After the appearance of this theory, the anatomas more than once paid the attention of researchers on the formation of air bubbles that should break the grip between water molecules in the vessels. However, in the case of the temporary exclusion of some vessel, the water moves along the spare ways (other vessels) or apoplast, and the air bubbles are gradually resolved with the participation of living cells.

The movement of water from the root into a sheet of dead vessels that have minimal water current resistance is one of the findings of nature, which is as follows. Vascular cells and tracheid are stretched in length, there are no living contents in them, inside they are empty, i.e. they are simple tubes. Wearing secondary cell shells are strong enough to break, capable of withstanding a greater pressure difference arising when lifting water to the top of large trees. End, and sometimes the side walls of segments of vessels, perforated; The vessels that consist of the connected segments are formed long tubes through which water with minerals easily passes. There are no perforations in the tracheids, and water to get from one tracheide to another must pass through their end walls; But the tracheids are very long cells, and therefore this structure is also very well adapted for water.

The exit in the process of plant evolution on land, the crown of which is quite far from the ground, has become possible due to the formation of a highly specialized conductive system. The value of this device is emphasized by the name of the plants themselves - vascular.

In addition to the difference in the mechanisms of action, there is complete consistency in the operation of two end engines. On the action of any factor of the environment capable of suppressing the operation of the lower engine, the sheet corresponds to the activation of transpiration, and vice versa. This is a biologically very important device, although at first glance, it looks paradoxically: the flow of water is deteriorating, and the sheet on this adverse factor is not in the suppression, but, on the contrary, an increase in transpiration. An increase in transpiration in this case aims to stimulate the flow of water to the root.

Now there is a look that in the plant there is a special regulatory system - hydrodynamic. Under its control there are water regime, maintaining water homeostasis, as well as some other functions, in particular, photosynthesis. The hydrodynamic regulatory system is very sensitive. It comes to action with a very small loss of water with a sheet (0.06% of the initial number) and prevents stronger dehydration in the future.

The transmission of the signal to the sheet occurs through a solid water flow, and the perception is an ascent and photosynthetic apparatus. The receptor of the shifts of soil conditions that slow down the flow of water is most likely the membranes of endodermal root cells.

The hydrodynamic regulatory system allows the plant to react very quickly to external changes, potentially unfavorable for water homeostasis.

Ground plants face a complex dilemma: on the one hand, they must have a fairly developed surface in order to effectively absorb sunlight and CO 2, and on the other hand, the water loss increases as the surface increases. This problem is solved different waysFirst, the flow of water increases due to the growth of the roots and the development of the hypertrophic absorbing surface. Secondly, water loss becomes slower due to the fact that the mesophilic cells are separated from the environment with a cuticle containing wax. Thirdly, the contradiction between the need to absorb more CO 2 and at the same time reduce the amount of evapoable water of the plant solved with the help of an oscillate mechanism.

Middle and Far Transport paths, the mechanism of movement of water on the plant (the water potential gradient, the driving forces of the ascending current of water in the plant, the upper and lower end motors, the processes of adhesion and cohesion).

Middle transport- This movement of ions, metabolites and water between cells and tissues (unlike membrane transport in each cell). Far transport- Movement of substances between the organs in the whole plant.

Transportation of substances in the plant is carried out according to any tissues and on conductive beams specialized for this purpose. In turn, the movement of water and dissolved substances can occur according to any tissues: a) through the cell walls, i.e., according to apoplast, b) on the cytoplasm of cells connected to each other by plasma modes, i.e. according to the symplast, c) According to the endoplasmic reticulum with the participation of Plasmodes.

The movement of water and substances by conductive beams includes transport on xylene ("upstream current" - from roots to the escape organs) and on the floem ("downward current" from the leaves to the zones of nutrient consumption or their deposits). Floam is transported by metabolites and when mobilizing spare substances.

Radial transport. By diffusion and metabolic processes, ions enroll in the cellular walls of risoderm and then through the cow parenchyma move to conductive beams. . This movement occurs both by cell walls - apoplast and in a simplast.

Moving ions by apoplast It occurs due to diffusion and exchange adsorption on the concentration gradient and is accelerated by the flow of water. Movement of minerals according to the symplast It is carried out due to the movement of the cytoplasm, and between the cells - by plasmodesma. The gradients of the concentration of substances contribute to the directional movement along the symplast. These gradients arise due to the fact that the substance received in the cell is included in the metabolic processes and the concentration is reduced.

Diffusion of ions and molecules according to the seeming free space of cells is interrupted at the endoderma level. The only path of further movement of substances through the endoderma is transport in a simplist, which is ensured by metabolic control of substances. Existence in endoderma bandwidths,in which the cappi belts are underdeveloped or absent, allows an insignificant part of the absorbed substances to avoid metabolic control.

Simplastic transport is basic for many ions. In this case, compounds containing nitrogen, carbon, phosphorus, to a lesser extent - sulfur, calcium, chlorine are subjected to active metabolization. Other ions metabolic control are practically not exposed.

Significant role in symployment of substances play vacuole. To a certain extent, they compete with the vessels of xylems for the absorbed substances and thus perform the role of the regulator of the admission of substances in the vessels. This process depends on the degree of saturation of the vacuolar juice by dissolved substances. With a decrease in the concentration of substances in the cytoplasm, they can again exit vacuoles, thus presenting a spare fund of nutrients. The absorption of the ions by vacuoles reduces the concentration of them in the symplast and ensures the creation of a concentration gradient necessary for the transport of them in a simplast.

How the ions come to the dead vessels of xylems, i.e. how is it loaded?

Xylene juice It is a solution, mainly consisting of inorganic substances. However, various nitrogenic connected (amino acids, amides, alkaloids, etc.), organic acids, amides, alkaloids, and other, organic acids, phosphorodorganic esters, compounds containing sulfur, are also detected in Pencle's Pumpbery when removing the upper hour of the stem. . In xylene juice, more complex substances falling here from vacuoles and cytoplasm of tracheal elements ending their development.

Ksilen juice in composition is sharply different from the vacuolargo. For example, the content of ion K + in pea epicotil vacuoles reaches 55 - 78 mmol / l, and in xylene juice - only 2-4 mmol / l.

Downloading xylems is most intensively occurring in the zone of root hairs. In this zone there are one or two pumps. The main one is localized in the platsmable cell of risoderma and cow parenchyma. It is due to the work of H + -POMP, which are proton-permeable redox chains, and proton-permissive redox chains. In this part of the root of cations and anions from cell walls come to the cytoplasm. Through the cells of the endoderma with the capping belts, water and mineral salts pass only through the symplast. In the parenchymal beam cells directly adjacent to tracheids or vessels, the second pump is functioning, separating mineral substances, which through the pores in the walls of the tracheal elements fall into their cavity. Due to the active work of two pumps in tracheids and vessels, the osmotic potential increases and, therefore, the sucking force.

When growing plants, watering undoubtedly delivers the greatest difficulties. On the one hand, it is a simple operation. But in order to evaluate how much water is necessary for one plant, and determine the time of watering, some experience is required. Whatever enough, but in the death of plants is to blame, as a rule, excess water, and by no means its drawback. Oarsaturated by water soil overlaps the roots access to oxygen, and stagnant cold water - Wednesday, conducive to the beginning of their rotting. Therefore, in most cases, regardless of temperature and season, the daily spraying of plants is preferable to watering the soil.

Solar energy Causes the action of special leaf organs - chloroplasts. Thanks to them, the leaves use carbon dioxide for the synthesis of carbohydrates, which in turn by various chemical reactions are converted to " construction material"From which plants consist.

A healthy plant consumes water from the soil.. Together with it, minerals rose to the roots are transferred along the stalk, and then they reach the leaves on the branches. From there, water tolerates substances synthesized in the leaves, to other plants, which in turn contribute to the development of leaves and roots

In breathing processes And many other chemical reactions occurring in the plant, water is absorbed. Therefore, in the period of growth, a lot of water is required. Water also transfers nutrients to those organs of the plants they need.

Prevention of rotting roots

Remove the plant from the pot and remove all patients of the roots - they acquire a brown color and become soft. Carefully pull the roots. If the external cover is easily separated, it means that the root rotes. All you can do to restore the plant is to trim dead roots.

Watering

The ability to estimate the need for watering plants - the quality coming with experience, which is acquired during the observation of the growth of the plant for a certain time. The Operation itself is simple. There are several rules that will help perform this operation.

Plant requires a lot of water during the growth period. It happens, as a rule, in hot spring and summer days, especially when the first kidneys and the plant blooms. But in the fall and in winter, when the temperature decreases, and most of the plants are at rest, water, on the contrary, it is necessary. Another thing is when the plant is in a very hot room. Then they need, just as it is done in the summer, watered often.

Many plants need winter pauseduring which they need some water. And there are also such, for example, cacti and Tolstyanka, which only need to wash. In the spring, in a period of strong growth, your plants require abundant watering. Immerse a vessel with a plant to the edges in a large water container room temperature And keep until then. While the surface becomes wet. Then remove it and let the drain of the water. A similar operation can be done with ampel plants that are suspended high and we can not always check whether it is well moistened with an earthen com.

Plants are better to water in the morningSo that excessive moisture can evaporate during the day. With evening watering, the plant altogether remains in a wet state all night, and the temperature drop contributes to the development of hazardous pest fungi. It can also lead to rotting roots.

Plant, fully filling the pot with its roots, It is necessary to water more often.

Frequency of irrigationthe type of soil also determines. Clay soils absorb water gradually, but also dried slowly; Sandy - very fast, but immediately become dry. Suglinic soils are ideal.

Plants in clay potscompared to plants in plastic pots, require water twice as much. The reason for this is that clay from its pore absorbs moisture, which evaporates through the pot walls.

Any plants with darous or sowed leaves such as SENPOLIA and SININGIA, It is impossible to water from aboveBecause wet leaves can bend or subjected to fungal diseases. First of all, be careful with cyclamen, because the water penetrates the middle of the tuber, which can be labeled with cutlets in the leaves and flowers in flowers. Pots can only be dipped to the edge in warm water About 5 minutes. Then you should give them to dry completely.

Various plants From the Bromeliev family Require in the center of the pot of at least once a week there was fresh water. But the plants-epiphytes, such as Tillandsia (Tillandsia), which are growing in nature on wood pieces, will be grateful for the daily spraying with water in the summer and for the weekly winter. But besides this, pay attention also to watering. If the plant is in a sunny place, avoid water from the flower and leaves.

Surface crust

It happens that the ground surface becomes tough, solid. In this case, water remains on the surface and does not penetrate the roots. Remove the crust from the ground. Make sure to damage the roots.

Dry soil

Peat, if not to maintain it in a wet state, settles, and when watering water, water completely flows out of the pot. In this case, immerse the plant along with the pot into the container with water temperature. Keep it there until the air bubbles come out from the ground.

Humidity tests

If you put a plant in a clay pot, tie it a cotton thread to a bamboo stick and slightly touch the pot. The sound sound suggests that clay, and the soil of dry, therefore, watering is needed. The deaf sound when hitting the pot indicates that the soil is humid enough.

Take the pot (no matter, clay or plastic) with a plant. If he seems to you hard, soil is wet, if easy, soil dry. This is a fairly reliable test, but it requires some experience for it, which allows you to develop the criterion of the optimal weight of the plant. And for large plants, he generally not applicable.

Before watering, you can check the condition of the Earth, Just touches her surface with your fingers. If the surface of the earth is dry, it means that the plant must be pole; If the land is still wet, then you can still wait with watering.

If you do not trust such tests, purchase humidity measuring device. The metal probe of the device is immersed in the soil. In its upper part, an indicator is installed, equipped with an arrow; It indicates the state of the soil: "Wet", "belch", "dry". With it, it is easy to find out if it is necessary to water the plant.

What water to use for watering?

Ordinary water from under the tap is acceptable for most plants, even if it is rigid, with a large lime content. But still for plants such as Azalea, Erica, Echmea Striped (Achmea Fasciata), use rainwater. These plants poorly carry lime. But in any case, using water water, Before irrigating, it should be gone a little to be a little so that it acquires the ambient temperature.

If you manage to dial rainwater In large quantities, water only all your plants. Otherwise, plants sensitive to calcium, water with cold water with cooked boiled water.

When spraying plants with water From under the crane, it can happen that, dried, water will leave ugly white spots on the leaves; This deposits of salts. You can easily remove them with a soft cloth or dry sponge.

Increase air humidity

Many plants are required increased humidity air, especially in dry and well-heated rooms. Therefore, you must create a fairly wet environment for them. One way to achieve this goal is daily spraying of water leaves From the usual sprayer. Do not forget that this operation must be performed in the shade. Another way is to put pots with plants on a wide tray, filled with a layer of gravel or small stones covered with water. Another way to ensure humidity is the immersion of each pot into the size of the vessel, such as a decorative container. After that, fill out the space formed between two vessels, peat, which should be kept in a wet state.

Posted on 01/15/2013

Vegetative and generative bodies, their functions.

The organ is called a part of a plant having a certain structure and performing certain functions. The plants distinguish the vegetative and genuine organs.

Vegetative organs are organs that ensure the basic processes of life (nutrition, breathing, protection and vegetative reproduction) are roots, stems, leaves, kidneys.

The generative bodies are organs providing sexual reproduction (flowers, fruits, seeds).

These organs can be modified (have an unusual structure and perform unusual functions).

Vegetative plant organs:

1. Root-axial organ that performs the functions of root food plants and fixing the plant in the soil.

Distinguish 3 types of roots:

the main root develops from the root of the seed

podep - from escape (stem, leaves),

side - from the main and apparent.

The inner structure of the root

The zones of a young root are different parts of the root along the length that perform unequal functions and characterized by certain characteristics of the structure. The young root usually distinguish 4 zones:

The division zone is the root top, 1-2 mm long. Here is the educational fabric, which ensures the growth of the root in length. This zone is protected by a root case of living cells formed by educational tissue.

The growth zone, or stretching - the zone is in the most millimeters following the division zone .. In this zone, cell divisions are practically absent, the cells are stretched as much as possible by the formation of vacuoles.

The suction zone is a zone of several centimeters, where root hairs are located. Root hairs is a side increase of the outer layer cells. The length of the root hairs is up to 8 mm. On average, 1 mm2 surface of the root is formed from 100 to 300 root hairs. It increases the total area of \u200b\u200bwater absorption and salts. The absorption of water contributes to the excretion of root hairs with acids dissolving mineral salts. Root hairs are short-lived, die in 10-20 days. There are new (at the top of the zone), new (at the bottom of the zone) come to replace (at the top of the zone). Due to this suction zone, it is always at the same distance from the tip of the root, and all the time moves to new parts of the soil.

The zone of the holding is above the suction zone. In this zone, water and mineral salts extracted from the soil, along the conductive tissues move from the roots up to the stalk and leaves. Here, due to the formation of lateral roots, the root branching occurs.

2. Stem is the axial part of the escape, carrying leaves, kidneys, flowers and fruits.

The main functions of the stem is a support, conductive, stocking.

Additional features: a vegetative reproduction organ, a photosynthesis organ.

Severe two main types of stems: herbaceous and rustic. Herbaceous - usually an existing one vegetative period, as a rule, not thicken (or weakly thicken) and unrehapsing (or weakly appointed). Herbaceous stems are most adapted to different conditions habitat. Rustic stems - usually perennial, thicken in vaguely long, consist of several layers:

Bark (Skin, Cork and Loubon) -st Cambia - Sisordsevin

Skin, cork performs a protective function.

Lentichki - tubercles with holes located in the cortex provide breathing stem.

Synotoid tubes of the Luba move organic matter.

Cambius is formed by the educational fabric and provides the growth of the stem in the thickness. As a result of the periodic activity of Cambia in the wood, annual rings are formed - the growth of wood in one growing season.

Wood vessels conduct water and dissolved salts.

The core performs a sparkling function (from the main peller tissue).

Lubyanny and wood fibers made of mechanical tissue perform a reference function.

3. Sheet - vegetative, bleached, side body escape.

The main functions of the sheet: photosynthesis, gas exchange, transpiration.

Additional features - stocking, protective, vegetative reproduction.

The sheet of most plants consists of a sheet plate, a puff, many leaves have hopes.

Sheet plate - extended, usually flat part of the sheet that performs the functions of photosynthesis, transpiration and gas exchange. Puffs - a narrowed part of the sheet connecting the leaf plate with the base and the regulating position of the sheet relative to the light. The leaves with sweets are called it, without cuffs - seating. If the base of the sheet in the form of a tube covers part of the stem (wheat), then such leaves are called vaginal.

Types of leaves. Distinguish the leaves are simple and complex.

Simple leaves - have one sheet plate.

Complex leaves are made up of several clearly isolated leafy plates, each of which is attached to a shaft with its cutlery.

The location of the leaves on the stem may be:

the next - the leaves are located for each other.

opposite - leaves are located against each other

mutual - from one node several leafy plates grow

the socket-loop is located on a shortened shoot.

The residence of the leaves is the location of vascular fibrous beams (residents) in the leaf plate. In the veils of the sheet, transport substances are carried out, and they maintain the shape of the sheet plate. There are several types of housing: mesh, palpal, arc, parallel.

Cellular structure sheet

Leaf top and bottom sheet is covered with skin - epidermis. Over the epidermum can be cuticle and wax. Cells of the top epidermis colorless and firmly fit to each other. The lower surface of the sheet is covered with epidermis with a variety of stomps. The dust is formed by two closing cells, between which there is a tight gap. Through the dust, gas exchange and evaporation of water (transpiration) occurs. Floating on the surface of water, the leaves of the dust is located on the upper epiderma, and the submerged leaves are usually absent.

Between the upper and lower epidermum there is a leaf pulp formed by the column and spongy cloth. A columnar fabric is located under the top skin of the sheet and its cells contain a large number of chloroplasts, where photosynthesis processes are carried out. Closer to the lower epidermome there is a spongy fabric that mainly performs the functions of gas exchange and transpiration. The cells of spongy fabric (sometimes irregular shape) are located, between them are well-developed interclausers, with the help of which gas exchange and transpiration is carried out. The cells of spongy fabric take part in photosynthesis, but to a lesser extent than the cells of the Parenhim, since the number of chloroplasts in them is 2-6 times less.

Sheet modifications

In the process of adapting to the conditions of the habitat, the entire sheet or part of it may occur in the external appearance and the inner structure, that is, modifies or metal metamorphoses occur. (See Fig.)

Buckles (1) are characteristic of plants living in a dry and hot climate, although they often occur in plants of other climatic zones. Spines reduce transpiration and protect plants from eating animals (for example, cactus barrels and barbaris).

A mustache (2) is a filamentary formation that is sensitive to touch and adapted for climbing. At Vika, lentils, peas in the mustache are converted to the top of the sheet.

Cutting devices (3) are found in plants growing on swamp, peat, poor mineral substances soils. With the help of removal of the devices, Rosyanka, Venus Mukholovka, non-tenty use organic food rich nitrogen and phosphorus, digesting animals.

Juicy scales (4) onions and garlic cloves, cabbage leaves are also modified leaves that perform the function of nutrients. Aloe, Agave (5) juicy leaves and perform the function of water.

The leaves can be modified in scales, for example, on the rhizas, on the kidneys, the leaves of the horsetail.

4. Escape - an overhead axial organ plant. It is a stem with leaves and kidneys located on it.

The place of attachment of the base of the sheet to the stalk is called the node, the angle between the camp of the sheet and the stem -pazha sheet, the kidney, which is in the sinus - stubborn kidney. The distance between the two nodes is called interstitial. Depending on the degree of development, intercosals distinguish shortened shoots (shoots with poorly developed short interstices) and elongated shoots (shoots with long interstices).

By the nature of the location in space, shoots are:

reprehension - with growing vertically upstroke;

rising - shoots, first growing in a horizontal, and then vertical direction;

peeling - growing more or less horizontally;

the sludge shoots are similar to those who are sharpening, but in contrast to them are rooted using the apparent roots formed in the nodes; (strawberry);

curly shoots are able to be stuck around other plants or any supports (field field, hops),

climbing (clinging) shoots have devices (mustaches, suckers, hooks, etc.) for retention on supports or on other plants (peas, grapes, ivy).

5. Kidney is a shortened breaker, i.e. It has all parts of escape, but they are in its infancy. Outside, renal scales are protected.

In the composition and kidney functions are:

vegetative - they develop shoots with leaves (in most plants). Inside the kidney is a reservoir stem, an ending cone of the rise and the embossed leaves. In the sinuses of the ridiculous leaves are laid in the ridiculous kidneys.

generative (floral, reproductive) - kidneys from which flowers or inflorescences are developing, that is, they only contain the concerns of a flower or inflorescences.

vegetative-generative (mixed) - kidneys, of which designer shoots with flowers (apple tree, pear, lilac). These kidneys are similar to vegetative, but the increasing cone is turned into a reservoir flower or inflorescence.

By location on the stem distinguish the kidneys:

top (on the tip of escape);

side (giving the following branching shoots);

stitched (developing in sinuses of leaves;

approve (any non-top and non-stitched kidneys; they arise in adult parts of the stem, root and sheet of inner fabrics).

Some kidneys remain unscrew many years.

They are called sleeping kidneys. In case of damage to the plant, the kidney "wake up", giving the beginning of new shoots.

Valid shoots

Weight modifications arise in connection with the acquisition of them special, additional functions. Basically, modifies are adaptive and are associated with the accumulation of nutrient reserves, vegetative reproduction, eating protection by animals, etc.

There are overhead and underground sections of shoots.

Overhead modified shoots:

Stokers - shoots with long thin interstices and serve for vegetative reproduction and resettlement. Strawberry teams are called mustache.

Spines - perform mainly protective function (Turn, apricot, pear, sea buckthorn, lemon, hawthorn).

Ugings - develop in plants with a thin and weak stem, which is not able to independently maintain a vertical position (grapes).

Meaty shoots - perform water-saving and assimilative functions (cacti, milk).

Kochan - a giant modified kidney, develops in the first year, accumulates nutrients in the leaves.

Underground modified shoots

Rhizhet is a long-term underground escape (Lily of the Lily of the Lily of the Lily, Valerian, etc.). Performs the functions of renewal, vegetative reproduction and accumulation of nutrient reserves. Externally resembles the root, but has the top and stubborn kidneys, the reduced leaves in the form of colorless scales. Candidage roots are developing from stroke nodes. Spare nutrients are deposited in the stem part of the escape.

The tuber - represents the thickening of underground escape (potatoes, Topinambur, Nasturtium, languorous). The formation of the tuber occurs on the top of the underground counteus due to the activity of the top kidney. The top kidney is thickened, its axis grows. Little Cellic Czech-shaped leaves die quickly and fall out, and in their place, leafy scars are formed - brings. In the sinus of each sheet in deepening there are groups of three or five kidneys - eyeballs.

Start \u003d "3" The bulb - is a shortened underground escape (onions, garlic, lilies). The stalking part of the bulbs - the Donette with strongly shortened interstices carries numerous juicy modified leaves - scales. Exterior scales are quickly depleted, dry and perform a protective function. In juicy scales, spare nutrients are postponed. In the sinuses of bulbous scales are kidneys, of which there are overhead shoots or new bulbs. At the bottom is formed apparent roots.

Generative bodies

6. Flower is a modified shortened limited growth escape designed for sexual reproduction. Since the flower is a modified escape, it distinguishes parts having a stem and sheet origin. The tank and the flower make is a modified stem, all the rest-modified leaves.

The main parts of the flower are a pestle (the female of the flower) and the stitch (the men's piece of flower). In the pestle distinguish a stitch, a column, marking. Inside the ovary there are soverees from which seeds are formed. The stitch consists of a stitching thread and the anther, where the disputes ripen.

The rest of the flower:

The crown - consists of petals, serves to attract pollinators.

A cup - consists of sewers, protects all parts of the flower in the booton stage.

The blossom is a shortened stem of a flower. It contains all other parts of the flower.

The flower make is an interstice under the flower. Flowers, devoid of flowers, are called si.

A whitewash and a cup form a perianth. The misfortune of the nonsense performs the function of protecting the main parts of the flower - pestles and stamens, the function of attracting pollinators. Distinguish the simple and double perianth.

A simple perianther is not differentiated for a cup and a whisk, formed by a set of homogeneous leaves that have the same dimensions and color.

Double picker differentiated on a cup and a whisk, different from each other with sizes and color

By the presence of pestles and stamens distinguish flowers:

obohylas - there is both a pestle and stitch (their over 70%).

separation flowers - have or pestle, or a latch. If there is only a pestle, the flower is called a pestle (female), if there are only stamens - a latch (male).

Depending on the finding of same-sex flowers on plants distinguish:

monocarbon plants - plants that have both female, and men's flowers (cucumber, corn, oak) on the same copies (cucumber, corn, oak);

double plants - plants that are on some copies are female, and on others - men's flowers (nettle, Iva, poplar, hemp, sea buckthorn, etc.).

7. Inflorescences are groups of flowers located in a certain order.

Functions of inflorescences - going together, small flowers become noticeable for pollinators

Simple inflorescences - flowers are located on the total axis:

brush - flowers with flowers in each other (lily of the valley, cherry)

colos - Flowers "Sitting" for each other

copper - flowers on thick axis (plantain)

umbrella - flowers flowers depart from the top of the axis (onions, primula, cherry)

head - "Sitting" Flowers around the rounded axis (clover)

basket - "Sitting" Flowers on a wide and flat axis (chamomile, sunflower)

Complicated inflorescences - Simple inflorescences are on the total axis:

complex spicy from simple spikelets (wheat, rye)

a complex umbrella - from simple umbrellas (carrots, dill)

makeup - from the brushes (lilac, oats, grapes)

8. The fetus is the generative body of coated plants, within which seeds are formed.

Fruit functions: formation, protection and distribution of seeds.

Fruits are characteristic only for flowering plants. The fruit is formed from the flower after fertilization. The main role in the formation of the fetus is played by a pestle. The bottom of the pestle is an ovary, containing the segments, grow up and turns into a fruit.

The fetus consists of spindlers and seeds, the number of which corresponds to the number of segments. Sometimes other parts of the flower (a blossom, stamens, perianth) take part in the formation of the fetus.

Classification of fruits.

1. According to the consistency of the ocopulodnik:

juicy fruits - have a juicy octoplodnik (berry, Kostyanka, Apple, Multi-Suspension, Tsyvina, Heperdia);

dry fruits - have a dry spindlers in mature fruits (bob, pod, box, nut, acorn, seed, grain, winid).

2. By the number of seeds:

single-headed fruits - mix in one seed (kitchen, nut, acorn, seed, grain, winid);

multi-free fruits - have a lot of seeds (berry, box, apple, bob, pod, multi-seater, multi-penette, hesperidium).

Fruits of different plants:

Berry- in currant, blueberries, cranberries, gooseberries, etc.

Kostyanka - in Cherry, Peach, cherry, plums, etc.

Multicast - in raspberry, cloudberries, blackberries.

Tsyvina - at pumpkins, melons, watermelon, cucumber.

Heperdia (Pomeranets) - Lemon, Orange, Mandarin, i.e. At citrusov

Bob - in legume plants: pea, soybean, clover, alfalfa, beans, etc.

Pod (pod) - in cruciferous: cabbage, radish, radish, mustard, etc.

Box - Poppy, Belen, Durana, Cotton, etc.

Walnut - in the flavory, walnut.

Overto oak.

Multi-soul strawberries, strawberries.

Wolf-maple.

Semyanka - all complex (dandelion, asters, chamomiles, sunflower, etc.)

Grain - all cereals (wheat, rice, corn, oats, millet, barley, rye, etc.)

9. Seed is a body of sexual reproduction, resettlement and experiences of unfavorable living conditions in seed plants, developing usually after fertilization from a nephery. A typical seed consists of covers (seed peel), embryo and nutrient tissue.

Seed skin - serves to protect the embryo from drying, mechanical damage. Forms from the cover of the nephery. On the surface of the seed peel, you can notice a small hole -Curprise, which is responsible for breathing, as well as the Rubber - the place of the former attachment of the sickness in the wound.

The germ of seed develops from a fertilized egg, has a diploid set of chromosomes (2P). The embryo in the inclusive form has all the main organs of the plant: the embryonic root, the skeleton, kids and the first embryonic leaves - cotyledoli. In dwallers - two seedlies, the monocycle is one of the seedlings.

Seed Flashing fabric (endosperm) develops from the fertilized central nucleus of the embryonic bag and has a triploid set of chromosomes (3P).

Features of the structure of seeds of domestic and monocotyledonic plants.

Many bipathic plants spare substances contain in cotyledons, and they have no endosperm.

Odnocil plants have span substances in endosperm, which is the main part of the seed. An embryo is adjacent to the endosperm, which is well distinguishable to the root, skelter, kidney and one of the seedlings.

Spreading fruits and seeds

After the formation of seeds either all the fetus, or seeds contained in it (or seed) are separated from the parent plant. The longer the seeds are spread, the less likely to competition from the parent plant. This also gives more chances to colonize the new territory, which over time leads to an increase in the size of the population as a whole. Methods for the resettlement of seeds and fruits in flower plants are very diverse.

Distribution with animals. The fruits fitted with spines or hooks are trailed to the skin or wool passing by animals and can be transferred to a certain distance before they are soda or disappear. Primers are the fruits of the chain, gravel, burdock, turn. Many plants have fruits with juicy ocoloblodnik to attract birds and animals. Seeds of these fruits are protected from digestion in the digestive tract and together with excrement fall into the soil, germinate, but already elsewhere.

Wind distribution. Many plants spread by the wind have special devices. These include pavements (seeds of Willow, Cyprus, cotton, dandelion fruit, etc.) and the winters (in pine (gone), a yase, ash, cock, grab, etc.). In a number of plants, for example, poppy, the fruit is a box, sitting on the leg, which the wind pegs, so that numerous small seeds are poured through the pores in the upper part of the fetus.

Water distribution. Only a few fruits and seeds are specially adapted to propagate with water. They contain air cavities, holding them on the surface of the water. Coconut - Kostyanka with numerous air cavities. The walker seed is supplied with spongy shell, the air pores of which do not give them sinking.

Self-discharges are spoiled by plants, in which the seeds are thrown out due to increasing in the fruits of internal pressure, or the ocoloblodnik ejects seeds on the principle of spring or throwing. This distribution of seeds is characteristic of a mad cucumber, sourness of ordinary, leguminous plants, in many iris, lilylays, primulous. Plants, spreading seeds, are usually growing in places where, for one reason or another, it is impossible to use other paths of resettlement (wind, animals). Most often they live in the deaf corners of the forest, where there is almost no wind, and where the beasts rarely pass.

In many cases, the element of chance is played in the spread of seeds and fruits, and this fetus or seed can spread in two or even with all three ways. One of the main factors of accidental distribution is a person; Seeds can enhance or stick to his clothing, etc. or transported with different cargo on vehicles. Close of cereals with weed seeds. A common phenomenon observed throughout the globe. Nuts, damaged about rodents, can stay, and germinate next spring. Floods, hurricanes, etc. can apply seeds further than usual. There are also fruits capable of crawling and jumping (Oats, Kickl, dr.).

Living and reproduction of vegetable organism, its integrity.

Plants, like all living organisms, breathe, feed on, grow, develop, multiply. In the vegetation organism there is an exchange and transport of substances, evaporation of water. But only in the vegetation body is a process of photosynthesis.

1) photosynthesis The essence of photosynthesis is that green plants due to solar energy from water and carbon dioxide with the participation of minerals create complex organic compounds. It goes in all green parts of the plant, where there are chloroplasts in the cells. But the main process of photosynthesis (air power) goes in the leaves. The energy of light absorbed by chlorophylls is on the synthesis of organic substances. As a result of photosynthesis, oxygen is released. Organic substances formed during photosynthesis are used for the processes of the plant itself, and oxygen - for breathing.

2) Breathing in plants is around the clock, unlike photosynthesis. Gas exchange is carried out through the dust, and when they are closed, oxygen comes from interclaudists. All the organs of the plant are breathing: stems (trunks) - through lentils (hillocks with holes in the crust), leaves - through the dust, the germ of the seed - through the micropile (hole), other organs through the entire surface. With breathing, organic substances are oxidized (destroyed) with heat release.

3) Power supply autotrophic (inorganic substances). The root (mineral) nutrition is distinguished using root hairs, and air power, so E.Photosynthesis. In the mineral nutrition, the presence in the soil of the main three elements: nitrogen (affects the growth of plant organs), phosphorus (affects the ripening of fruits), and potassium (affects the development of the root system).

4) evaporation (transpiration) - occurs through the dust (the main part) and through the coverings of the organs. Evaporation depends on the time of day, temperature, air and soil moisture, the amount of stomach on the leaves, etc. By evaporation on the plant, water and salt are moving, the plant is protected from overheating in hot weather. Evaporation is regulated by opening and closing the dust. Excess CO2 at night when the plants breathe, and the photosynthesis is missing, causes acidification of the cytoplasm, the change in the pH leads to the closure of the dust. In the absence of light, photosynthesis in closing cells ceases (as in all other), the tour pressure decreases and the hydrian is closed. With a lack of water intake in the plant, the Ustian also closes, saving in such a way, then a small amount of moisture that is available to the plant.

With increasing moisture content of the soil and air, the dust open, with a decrease in the concentration of carbon dioxide in the air - the dust open, but at temperatures above 35? C - close. The evaporation rate also depends on the wind, which blows a wet film of wet air from the surface of the sheet, so the plants of dry seats are often dusted.

The number of stomps in plants depends on the habitats - the land of habitat, the smaller the stomach on mm2.

5) Transport substances in plants are carried out at the expense of conductive tissues. Water and minerals are absorbed by the plant from the soil with root hairs, enter the vessels and fuel of the stem and rose up due to root pressure and transpiration (water evaporation by leaves). The transport of organic substances perform the sieve tubes and cell-satellites of the Luba. On them, dissolved organic substances move in two directions - up and down (as opposed to vessels along which water and mineral substances are transported only upwards). Horizontal vehicles of organic substances in core cells and back is carried out according to the core rays that connect the lob and core. The velocity of the substances depends on the ambient temperature. The higher the temperature, the faster there is a transpiration, the power of root pressure increases and transport substances are increasing faster. In winter, the planting in plants ceases.

6) Growth is an increase in the size of the plant and its organs. It goes due to the educational fabric located in various organs, and by accumulating in nutrient cells. The roots grow long due to cell division located in the division zone. The stalks are growing in length due to cell division in the increase in the rise in the tip of the top kidney (the top height) or by dividing the cells at the base of the interstitial (inserting growth). Inserting the stem growth is characteristic of cereal plants. The growth of the stem in the thickness is due to the division of Cambia cells.

7) Development is qualitative changes in the plant during individual development. In the development of plants, an alternation of generations is observed: an affordable (sporophyte) and sexual (gamemarketophyte). Development of disputes begins with sprouting germination.

At Mukh, under favorable terms, the dispute germinates in a proton - green, branching thread. Special kidneys are laid on the proton, of which the Gametophyte (plant itself) is developing over time. On male plants, spermatozoa ripen, on women's - egg cells. Fertilization occurs in the presence of water. After fertilization on a female plant, a diploid sporefield is developing - a box, where haploid disputes are formed as a result of meiosis.

Fern-like spores is a perennial plant, having a complex structure and tissue differentiation. Gamenaophyte is called a reproduction and is a small green plate developing from a dispute. Men's and female gametes are formed on them. In the presence of water (dew, fog, rain), mobile men's gamets reach egg cells, fertilization occurs and zygote is formed. It gives the beginning of the diploid sporophyte. Initially, it has a root, skelter and the first sheet and feeds due to the ingredient, but as the root system develops, it moves to independent meals and becomes an adult plant. The adult plant develops sporangies where Meiosis occurs, and haplid disputes are formed.

etc.................