All plants consist of vegetative and generative organs. The latter are responsible for reproduction. At coated plants this flower. It is the vegetative organs of the plant - this is the root system and shoots. Root system Consists of the main root, side and additional. Sometimes main root May be unfinished. Such a system is called urine. Savages consist of stems, leaves and kidneys. Stems provide transportation substances, as well as maintain the position of the plant. The kidneys are responsible for the formation of new shoots, as well as flowers. The sheet is the most important organ of the plant, as it is responsible for photosynthesis.
How he is arranged
Consist of several types of fabrics. Let's look at them in more detail.
From the point of view of histology
From above is the epidermis. This is a layer of a thickness of one or two cells with dense shells, located very close to each other. This fabric protects the sheet from mechanical damage, and also prevents excessive evaporation of water from the organ. In addition, the epidermis is involved in gas exchange. To do this, the tissue is pretty.
On top of the epidermis is also additional protective layerwhich consists of wax excreted by the cells of the coating fabric.
Under the layer of epidermis is a columnar, or assimilant parenchyma. This is a sheet. It takes the process of photosynthesis. Parenchyma cells are vertically. They contain a large number of chloroplasts.
Under the assimilation fabric there is a conductive system of sheet, as well as the spongy parenchyma. - This is Xilem and Floem. The first consists of vessels - dead cells connected vertically with each other that do not have horizontal partitions. According to xylem, water with substances dissolved in it enters the root sheet. Floem consists of elongated living cells. According to this conductive tissue, solutions are transported, on the contrary, from the sheet to the root.
The spongy fabric is responsible for gas exchange and evaporation of water.
Under the listed layers is the lower epidermis. It is as well as the top, performs a protective function. It also has a dust.
The structure of leaves
From the stem, the stuffing is moving on which the sheet plate is fastened - the main part of the sheet. From the cut to the edges of the sheet, veins are departed. In addition, its connections with stem are welcome. Complex leaves, examples of which will be discussed below, are arranged in such a way that there are several sheet plates on one cut.
What are the leaves
Depending on the structure, simple and complex leaves can be distinguished. Simple consist of one plate. A complex sheet is one that consists of several plates. It can be diverse in structure.
Types of complex leaves
There are several types of their types. The factors for separating them on species can be the number of plates, the form of edges of the plates, as well as a sheet form. It happens five types.
Sheet form - what it happens
There are such types:
- sweatshop;
- oval;
- ring-shaped;
- linear;
- heart-shaped;
- fero-shaped (semicircular sheet);
- pointed;
- needle;
- wedge-shaped (triangular leaf, attached to a stalk at the top);
- spear (acute with spiny);
- shovenoid;
- paddle (sheet is divided into several blades);
- lancing (long, wide in the middle sheet);
- inversely drugsoid ( top part Sheet is wider than the lower);
- frequency-like (leaf in the shape of a heart, attached to the stalk with an acute end);
- rhombid;
- sickle.
A complex sheet may have plates of any of the listed forms.
Form of edges of plates
This is another factor that allows you to characterize a complex sheet.
Depending on the shape of the edges of the plates, the leaves are five types:
- gear;
- gallant;
- pilly;
- lavety;
- all-ray.
Other types of complex leaves
Depending on the number of plates and their location, the following types of complex leaves are distinguished:
- palpal;
- pirish;
- double;
- three-lines;
- perresty cut.
In the painted complex leaves, all the plates diverge on the radius from the cutter, reminding his face fingers.
Curly leaves have leaf plates located along the cutter. They are divided into two types: paired and unparallers. The first does not have a top plate, their number is multiple two. Non-parpecical, the top plate is present.
The double leaf leaves are located along secondary cuffs. The same, in turn, are attached to the main one.
Three-line possess three plates.
Perresty leaves are similar.
Complex leaves - their dwelling
There are three types:
- Go exactly from the base of the sheet to its edges over the entire record.
- Arc. The veins go not exactly, but in the form of an arc.
- Mesh. It is divided into three subspecies: radial, palpat and peristional. With radial housing, the sheet has three main veins, which remain the rest. Palp is characterized by the presence of more than three main veins, which are divided not far from the base of the pet. With a peristolete leaf, there has one basic vest, which remains the rest.
The most often complex sheet has mesh housing.
Location of leaves on the stem
And simple, and complex leaves can be located differently. There are four types of location:
- Mutter. The leaves are attached to three pieces to a narrow stalk - a muve. They can be cross, with each mutant relative to the previous one rotated 90 degrees. Plants with this location of the leaves are Elodea, the worsion of the eyes.
- Outlet. All leaves are on the same height and are located in a circle. Such rosettes have agawa, chlorophytum.
- Sequential (next). The leaves are attached one for each node. Thus, they are located near the birch, pelargonium, apple trees, roses.
- Opposite. With this type of location, two sheets are located on each node. Each node is usually rotated relative to the previous 90 degrees. Also, the leaves can be located two rows without rotation of the nodes. Examples of plants with this location of the leaves are mint, jasmine, lilac, fuchsia, clarity.
The first two types of sheets are characteristic of plants with simple leaves. But the second two species can relate to complex leaves.
Examples of plants
Now let's consider different kinds Complex leaves with examples. They allocate enough. Plants with complex leaves can be different vitality. It can be bushes, and trees.
Very common plants with complex leaves - ash. These are the trees of the family of the Maslin, the class of dietary, the separated departments. They possess unparalleled complex leaves with seven-fifteen plates. The edge shape is toothed. Residential - Mesh. Ash leaves are used in medicine as a diuretic.
A bright example of a bush with complex leaves can be called raspberry. These plants have nonpoprisy leaves with three-seven plates on long stiffs. The type of housing is peristuter. The shape of the edge of the sheet is Golden. Raspberry leaves are also used in folk medicine. They contain substances with anti-inflammatory effect.
Another tree with complex leaves - rowan. Leaves of her parsley. The number of plates is about eleven. The jilling is peristoneant.
The following example is clover. It has complex treasured leaves. The housing of the clover is mesh. Sheet edge shape - Obsolenic. In addition to clover, the troopy leaves also possesses a bobcover.
Complicated leaves also have such plants as Albia. It has two-purpose leaves.
Another bright example Plants with complex leaves - acacia. This bush has mesh housing. The shape of the edge is all-ray. Type of sheet - double. The number of plates - from eleven pieces.
Another plant with complex leaves is strawberries. Type of sheet - three-lines. Residential - Mesh. These leaves are also used in folk medicine. Usually, atherosclerosis and other vascular diseases.
Conclusion
As an output, we give a summary table of complex leaves.
| Type of complex sheet | Description | Examples of plants |
| Pallen leaves | Plates diverge from a stuff fan, reminding the fingers of a man | Kishtan Konsky |
| Nonpopriste | The number of plates is odd, there is a top. All plates are located along the main stuff | Ash, rose, rowan, acacia |
| Parserous | The number of sheet plates is odd, the top is missing. All of them are located along the main stiff. | Peas |
| Doubles | The plates are attached to the secondary stiffs growing from the main stiff. | Albia |
| Trophy (three-lines) | Have three plates that depart from the main stiff | Clover, Bobvnik |
| Perresty cut | The plates are arranged by the type of centers, but not separated completely | Rowan |
So we considered the structure of a complex leaf, which they possess.
Sheet - Part of escape. Externally, the leaves of different plants differ greatly, but there is a lot of common between them. The leaves of most plants have a green color and consist of sheet plateand cherishwhich they are connected to the stem.
Some plants of the alkali are located in parallel one another. That venation Call parallel. It is found in many single-bedroom plants. Arc The dwelling is also characteristic of monocotyledonic plants.
W. dichomotor plants Allowers are repeatedly branched and form a solid network. it mesh venation.
But there are exceptions. For example, at a monocotary mouth of the Voroniye, the leaves have mesh housing. 
If one leaf plate is on the cut, the sheet is called simple.
A sheet consisting of several leafy plates connected to a shared sweet with small cutters, called complex. In such leaves, each plate is usually popped independently of others.
We will get acquainted with the inner structure of the leaf plate. Sheet plate consists of a variety of cells different quantity and forms, that is, has cellular structure. From the top and from the bottomside, the sheet is covered with more and less identical cells, tightly adjacent to the other. These are skin cells, which covers the sheet and protects it from damage and drying. Skin- One of the types of plant fabric plants. Skin cells are colorless and transparent, but among colorless cells there are green spaces changing cells. Between them is a gap. These cells and the gap between them are called ustian. Through the digestive gap inside the leaf penetrates the air and go into the atmosphere of water pairs, oxygen and carbon dioxide.
In most plants, the Ustian is only in the skin of the lower side of the sheet plate.
Under the skin are the cells of the leaf pulp. Sheet pulp consists of several cell layers. One of the layers directly adjoins the upper skin. His cells resemble rather equal columns. They are especially many chloroplasts. Deeper lie more rounded or incorrect form cells; They fit tight to each other. Spaces between cells call Interclauders. Interclauders are filled with air. The pulp cages are green, because in their cytoplasm there are green plasts - chloroplasts. The color of chloroplasts is explained by the presence of chlorophyll in them - the pigment of green green. Chlorophyll in chloroplasts is formed only in light. Chloroplasts of flowering plants in their form are sometimes called chlorophyll grains.
If we consider under the microscope internal structure Sheet plate, you can see the cut across it vein. They are found in cross sections of cells - vessels, synoid tubes and fibers. Thus, the veins are conductive beamssheet. Strongly elongated cells with thick walls - fiber - give the sheet strength. Water and mineral substances dissolved in it are moved by vessels. Synotoid tubesUnlike vessels, formed by alive long cells. Transverse partitions Between them are permeated with narrow channels and look like a sieve. Sitting tubes from leaves are moved by solutions of organic substances.
Plants capture light mainly leafy plates. Some plants with short stems are collected in roasting sockets, and sunlight falls on each sheet. Many plants are capable of leafing, turning the record to the light. This makes it possible to better absorb the sun's rays. For example, in Ivy leaves are always facing the light, and if the plant turn, after a while, the leafy plates will also turn to the light and will be located in the form of a sheet mosaic, almost without shading each other.
Water evaporates from the surface of the sheet. Inside the leaf of water vapor interclauders passes to the hydrians and evaporates mainly through them. Especially a lot of water evaporates young leaves. Different plants evaporate miscellaneous number water. Evaporation depends on the surrounding conditions and state of allocations. If the plants are enough water, the dust is open in day and night. Some plants are dotted only during the day, and close at night. Thus, evaporation is regulated by opening and closing the dust.
Plants of wet rainforests - ficuses, begonias, phylogendron - have large leaves, evaporating a lot of moisture. Appearance The plants of arid areas are also peculiar. The leaves of these plants are small. Sometimes they are like cacti, spiny replace. The leaves of many plants of dry places are adapted to reducing evaporation. It is a thick omission, a wax flare, a relatively small number of stomps and other devices. For example, Aloe, agave leaves fleshy and juicy. Water is inhibited in them.
Leaves can be modified and because they play any other role, not characteristic of typical leaves. For example, Barbaris has some leaves turn into spines. They evaporate less moisture and protect the plant from eating animals. In the pea, the tops of the leaves turned into the mustache. They serve to maintain a plant stem in a vertical position.
Interesting leaves insectivorous plants. A small plant of Rosyanka is growing on peat swamps. Rosyank leaf plates are covered with hairs excreasing adhesive liquid. Brilliant, like dew, sticky droplets attract insects. On the sheet insects are felt in the adhesive liquid. First, the hairs, and then the plate of the sheet bend and cover the victim. When the plate and the hairs again turn around, only its covers will remain from the insect. All alive insect leaf fabrics will digest and sucks.
In the fall, the leaves are gradually yellow and blushed due to the destruction of chlorophyll. By autumn, unnecessary plants accumulate in the leaf cells, and sometimes harmful substances for them. Falls begins. The leaf fall is also a fixture of plants to reducing evaporation in the fall and winter.
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In the botany, the leaves are an integral part of the plant's stem system. The wood leaf consists of a sheet plate (flattened part of the sheet), a petiole (stem) and horses (appendages at the base of the sheet). Leaves on trees are of various shapes and sizes. All the crown of wood should occupy a fairly large area of \u200b\u200bthe tree surface, this is important for absorbing the light by chlorophyll in the process of photosynthesis and carbon dioxide (CO2) for the production of organic molecules.
Such different leaves
As a rule, a sheet of wood consists of a wide blade (plates) attached to the stalk. The leaves are different in size, form and some other characteristics, including the type of housing (the location of the veins). Different types Jobs are characteristic of different species Plants, for example, two-bedrooms have mesh housing, in monocotional plants, the leaves are parallel. Leaves can also be simple and composite.
List structure and function
Tree leaves perform a number of essential functions, and also contain water, which is necessary to convert light energy into glucose during photosynthesis. The leaves have two structures that minimize the loss of water - the cuticle and the dust. The cuticle is a wax rode on the top and bottom of the leaves, which protects water from evaporation into the atmosphere.
The main function of the sheet is the production of food for the plant by photosynthesis. Chlorophyll, substance that gives plants characteristic green color, absorbs light energy. The internal is under the protection of the epidermis. The central sheet, or the mesophyl, consists of a soft wall, its cells are known as parenchyma. On one fifth, the mesophyll consists of chlorophyll containing chloroplasts. They absorb solar light to extract oxygen, and, in combination with certain enzymes, hydrogen is mined from water.
Oxygen released from green leaves is used for the respiration of plants and animals. The hydrogen derived from water, in combination with carbon dioxide, participates in the enzymatic processes of photosynthesis in the form of sugars, which are the basis of the plant and animal world. Oxygen enters the atmosphere through special pores on the surface of the leaves.
Although the cuticle performs an important function of protection against excessive moisture loss, the leaves cannot be impermeable, because they should also allow carbon dioxide gas. After CO2 penetrates a sheet through the dust, it moves into mesophyll cells, where photosynthesis occurs with the subsequent production of glucose.
What does leaves color depend on?
The color corresponds to chlorophylls, green pigments, which are usually present in much larger quantities, than others. In the fall, chlorophyll production slows down, as the days become shorter and cooler. Gradually, chlorophyl collapses and disappears, and the colors of other pigments begin to manifest. They include carotene (yellow), xanthofill (pale yellow), anthocyanine (red, blue-violet) and betacianine (red). Tanines give for example, the oak leaves their dark brown shade.
Life Life
The wood leaf is mainly short-lived structure. Even when they persist for two or three years, for example, coniferous and broadly evergreen plants, then after the first year they bring the whole tree not so much benefit as at the beginning. The leaves begged at the base of the sheet of the sheet. This is usually happening in autumn, although other factors can have influence on this natural biological process, for example, the exhaustion may be due to injuries associated with insects, diseases or drought.
Closer to autumn, the wood leaf undergoes some age changes, as the days are becoming shorter, and sunlight is less and less. As a result, the stuffing zone begins to soften until the leaf disappears. The healing layer is formed on the stem, which delays the wound, leaving a kind of scar.
Composite parts of sheets
The main leaf of coated brine consists of the base of the leaves, strippers, sweet, and blades (plates). The base of the leaves is slightly expanded in the place where the sheet is attached to the stalk. Paired strips, if available, are on each side of the base sheet and resemble scales, spines, or structures resembling the leaf itself. The stiff is a stem that connects the blade with the base of the leaves. The blade is the main photosynthetic surface of the plant.
Types and shapes of leaves
The shape of trees leaves can be different. In nature, simple and complex leaves may occur. When only one blade is connected to a camp, then the sheet is called simple, it also, in turn, can be dissected along the edges. different ways. Such leaves can be whole and even, as well as they can have gear or saw fields. Also, edges can be rounded or fester. Big variety are found on top and at the base of the sheet. There are leaves that do not have a stuff and they are attached directly to the stalk, and some leaves may not have hop.
By type of location, the types of leaves of trees can be allocated as follows: the next, pair (on the contrary) and mutual. At the next location, the leaves are evenly distributed over the stalk, alternately forming an ascending spiral. In the pair location, the leaves of the plant are opposite each other. The plant has a woven type of location when three or more leaves come from one node.
Needles are also leaves
The form of the leaves is the main tool for identifying plant species. Coniferous types of plants, such as spruce, fir, and pine growing in cold conditions have the leaves in the form of a needle. The needy leaves help in reducing water losses. In the hot climate, plants such as cacti have succulent leaves, which also help to save water. Many aquatic plants have leaves with a wide plate floating on the surface of the water, with a thick wax cuticle on the surface of the leaves pushes water.
Regarding the distribution of plants on Earth, the climate is the determining factor, which is why the vegetation zones almost always correspond climatic zones. From climate features and ambient The diversity of species and forms of vegetation is fully dependent. The leaves that are primarily photosynthetic organs are also adapted to climatic conditions The most optimal way.
People write poems and songs about them, admire in the spring, summer and autumn, are looking forward to their appearance in winter. They are a symbol of the life and revival of nature, a gentle apparel, angle-minded eye and donating pure oxygen to everything alive on Earth. These are the leaves - what we see every day and something will not be able to live a single plant, and our entire planet.
- The leaves are yellow over the city turn, with a quiet rustle, we fall under the feet ...
- Maple Leaf, maple Leaf, you dreamed of me among the winter ...
- Leaves green ringing to all those who were in love ...
What is the leaves, why do they need, why yellow in the fall and again grow in winter, what color and form are - all this and much more you will learn from this publication.
Functions of leaves, their role in the vital activity of plants
If we say dry scientific, Sheet is one of the most important organs of the plant, the main function of which is to participate in the process of photosynthesis.
[!] Photosynthesis - Conversion solar energy in organic compounds Inside the plant. Simply put, thanks to photosynthesis, plants get food from sunlight.
In addition, with the help of the leaves, the plant breathes and evaporates moisture (allocates dew).
As you can see, without green covers, the life of the plant would be impossible, but not only the plants depend on the leaves. With these peculiar light, the plant neutralizes carbon dioxide and highlights oxygen, necessary and to people, and animals, and insects, that is, everything is alive on the planet.
In general, the sheet consists of several parts:
- The base is the place of attachment to the stalk;
- Half-leaf elements at the base, in some cases fall after the sheet is completely revealed;
- Puffs - continuation of the main vein suite, connecting sheet and stem;
- Sheet plate - a wide part of the sheet that performs its main functions.
Since each plant is individually, and the leaves are very different, some parts may not be. For example, it is often missing, sometimes there is no petiole (in this case, the leaves are called sedentium or pierced). In addition, all parts may be the most various shapes, Length and buildings.
The classification and separation of the main parts helps scientists-botany correctly identify the plant and determine which family, family and order it applies.
Building, species and shapes of sheet plate
The sheet plate consists of an upper epidermis, coated with a cuticle, a paleous layer, a spongy layer and lower epidermis, also covered with a cuticle. Each of the layers performs a specific function:
- Cuticle and epidermis protect the plate from external influences, prevent excessive evaporation of water.
[!] For the delay process of the necessary moisture inside the sheet, the dust is responded - paired cells capable of closing and not to give moisture to evaporate. Stwitz start their work in drought, saving a plant from dehydration.
- The palersaded layer, also called a columnar cloth, is responsible for the process of photosynthesis. Chloroplasts are collected here, cells staining the surface of the sheet in green.
- Sponge fabric - base plate. Its functions - gas exchange, absorption of carbon dioxide and the release of oxygen, and photosynthesis.
The entire plate is permeated with conductive beams, called veins, for which the delivery of organic substances is carried out from the root to the sheet (water and minerals) and, on the contrary (sugar solution). In addition, the veins form a solid skeleton that protects soft fabric from breaks.
Forms plate
In general, all the forms of the leaves are divided into simple and complex, and complex ones, trunk, peristrays, which, in turn, are divided into several types. Total Botany has at least thirty-five species of forms.
Simple leaves consist of one sheet plate, while it may be the most of different shapes: round, oval, rhombid, elongated, and so on. The outline of the tip of the plate and the stuffing place is also different.
Those complex are called those leaves that consist of several parts, both articulated on a common petiole (blade, dissected, separate) and having their own separate petioles (finishing, pile, three-lines).
[!] One of the signs of complex leaves is their fiction at different times.
In addition to the overall configuration of the sheet, its base (round, heart-shaped, trollovoid, unequal, etc.) is distinguished, and the top (pointed, laid, oral, dull, etc.).
Form forms
The edge of the sheet, as well as his general form, prompts the botany affiliation of the plant to this or in a different kind. Depending on the depth of dissection, the edges are divided into finger or gear (shallow recesses), blade, dissected and separate (deep excavations). Smooth edges are called one-piece.
Types of housing
The housing pattern of the sheet plate can be very diverse and depends on the type of plant. In general, all housing types are divided into two parts:
- there are several parallel veins through the leaf plate, the central vein is missing (parallel dwelling),
- there is a main (central) vein, from which side (net deputation) is branched off,
- several curved veins divergent in the middle of the sheet and converging to the edge (auxidine dwelling).
In turn, mesh jilk is divided into several subspecies.
Types of granting and cuffs
Half is usually similar to a small underdeveloped leaf, located at the base of the sheet. They may fall after the sheet opens completely, or remain on the plant. Depending on the method of fastening to the petorant, horses are free, struck with cushion, inter-axis, cross-shaped or stuffing stuffing.
Cells can differ in the shape of cutting: a cylinder, a semi-cylinder, with a notch and others. In addition, as mentioned above, the stiff may not be completely, in this case the sheet is attached directly to the stalk.
As you can see vegetable world It demonstrates an amazing variety of forms, while there are millions of their combinations.
So, the scientific and botanical part is over, it's time to go to amazing facts About leaves.
How plants adapt to climate and other habitat with leaf leaves
Each plant is forced to acclimatize to weather conditions, as well as to protect against external influences. All parts of the plant: roots, shoots, flowers and, of course, the leaves, adapted to various climatic phenomena: high or low temperatures, drought or excessive humidity, lack or excess of sun rays. In addition, people and animals threaten plants, so many of them in the process of evolution learned to reflect attacks.
Consider how with the help of your green cover the plant is opposed to an unfavorable environment.
Arid or wet climate:
- The small size of the leaves and, accordingly, the small area of \u200b\u200bthe sheet plate is preventing excessive evaporation of water;
- The leaves are usually thick, juicy - thus the necessary moisture accumulates in them;
- The leaf plates of many plants are covered with hairs, which also prevents evaporation;
- The same purpose serves a smooth wax raid on the surface.
- Large leaves - sign of plants of tropical climate, due to big size Plates The evaporation process occurs much more intensively.
Crasus, Senpalia, Philodendron Windy areas:
- Embroidered, the rugged edge shape fluently passes the air flow, due to this wind gusts do not injure the sheet.
Birch Humidated "Dalacarly", Monster, Maple Palm Places with excess or insufficient sunlight:
- If sunlight is not enough many plants can deploy the leaves in such a way that as much as possible solar rays fell onto their surface;
- Sheet mosaic is a phenomenon in which the smaller leaves are located between larger meetings. In this case, each sheet catches the sun's rays and participates in the process of photosynthesis;
- Some plants that do not need large quantities Sun, filtered light through special translucent windows located on the leaves.
Dandelion, Ivy, Fengestrairia Water plants - These Flora representatives are a mansion, because they, to survive, had to adapt even not to the climate, but to a completely different element - water:
- Leaves of guidophytes (plants that are completely immersed in water) are strongly disseminated. Thus, increasing the surface area, the plant gets required amount oxygen;
- Leaves floating over the surface of the reservoir do not have alloys on the reverse side of the sheet plate;
- The large surface area of \u200b\u200bfloating leaves does not give them to drown through the load distribution.
- Special microscopic protrusions and wax layer prevents water penetration inside the sheet, excluding the plant infection with microorganisms and the simplest algae. Water is not absorbed into the surface, but flows along the leaf drops, at the same time cleaning it from dust and dirt. This phenomenon got the name "lotus effect."
Rogolitnik, Victoria Amazonian, Lotus Protection against animals and people. Some plants during evolution learned to defend against encroachment:
- The leaves produce strongly smelling pheromones and oils that scare animals;
- Sheet plate is covered with soft hairs or even solid spines, staring of the aggressor.
Geranium, nettle, clean woolly Unusual leaves
Nature endowed certain types of plants such an extravagant appearance, which sometimes determine where the leaves before us - it seems to be a difficult task.
Cacto-shaped settled in areas with a dry climate, where the loss of every drop of water is equivalent to death. Evolutionary selection has made its work - survived specimens with the minimum area of \u200b\u200bevaporation. Wide leaves - incomplete luxury for such conditions. All exterior decoration of cacti, inhabitants of anhydrous wastewhere - compact protective leaves-spines.
Sucmation, Triecelius, Slubberger Other plants of arid areas in order not to evaporate the precious moisture, and they decided to abandon the leaves at all. Rather, the leaves remained, but only in the form of small undeveloped scales. At the same time, the form of the sheet and the function of photosynthesis has gained shoots, called loosen or filocades. Fillocada was so adapted to the new role that externally practically did not differ from the usual sheet, but are not actually such.
There is also an option on the contrary - what seems of shoots, in fact is the leaves. One example is the ammunition of crawling plants. In this case, the antennae is the tops of the leaves, gently adjusted to cling.
Ilitian, Asparagus, polka dotted fence Some of their most unusual leaves belong to tropical exotions. The hot wet climate, the abundance of insects and animals forced the plants to adjust the difficult conditions of existence and even go into the category of predators. With the help of sticky secretion or special bubbles on the leaves, predatory plants Catch the goded insects, and then suck out the life juices.
Another device tropical plants - Bag formed by the controversial planes of the sheet plate. In this trap going rainwater, the stock of which, if necessary, is consumed during periods of drought.
Rosyanka, bubble, Dyshidia Raffleese Leaves of different colors
What color are the leaves? At first glance, the answer to this question is very simple - green in summer, yellow and red in autumn. In fact, they can be the most different colors Not only in autumn, but at other times of the year. You can meet green, yellow, red, silver burgundy and, even, purple shades of painting of natural decoration of quite healthy plants. In addition to unusual pigmentation, on the leaves of some, especially southern, plants there are beautiful patterns and ornaments.
Zebrina, Fittononia, Caladium
The leaves are not only pleased with the eyes and are necessary for the life of the planet, some of the leaves are also edible and, moreover, they constitute a considerable part of the human diet. In the cooking, they are used as a vegetable component: spinach, mangold, Beijing, Chinese cabbage, and as a salad ingredient: arugula, sorrel, lathouse, and, of course, as a season with a seasonality: dill, parsley, basil, mint, and so on.
Beijing Cabbage, Latuke Salad, Basil Answers on questions
At the end of the article - the answers to the most popular questions about the leaves.
Why is the sheet flat?
Such a form increases the area of \u200b\u200bthe leaf plate, and, in turn, a large surface area increases the number of cells involved in the photosynthetic process.
What does the sheet size depend on?
Size and, accordingly, the surface area of \u200b\u200bthe sheet depends on the habitat of the plant. The leaves of plants from arid areas are usually small, and from wet places are large. The fact is that than more square Sheet, the greater on its surface of the dough and the more intensively the water evaporation occurs. Where there is often drought, to survive plants try not to evaporate a lot of moisture, and in the tropical climate, the evaporation process, on the contrary, should be as intense as possible.
Why leaves green?
The green color of the sheet corresponds to chlorophyll, participating in the conversion of carbon dioxide in nutrients. The high chlorophyll content in the leaf plate gives the robe of plants. Fresh green shade.
[!] Chlorophyll of some plants are painted in other colors - red, brown, purple, so leaves of such plants have appropriate shades.
Why leaves yellow?
In the fall, chlorophyll is destroyed in the leaves, it becomes less. Due to the reduction of chlorophyll, the intensity of the green spectrum is gradually reduced. The forefronts are yellow and red pigments (xanthofill, carotene, anthocian) contained in the sheet cells.
[!] The leaves of individual plants do not change the color and fall in green.
Why leave leaves fall in autumn?
Seasonal changes in the duration of the daylight and medium daily temperaturesForced plants to adapt to changeable conditions of existence. To the onset of winter cold most of The flora resets the summer decoration and goes into an anabiosis state, taken to call the winter hibernation. Exchange processes B. life systems Plants almost stop. The leaves, so necessary in the summer for evaporation of excess moisture and the collection of lively sunlight, become simply unnecessary and fall.
During the spring and summer, the leaves mined and processed nutrients necessary for the vital activity of plants. In the process of such recycling, green light nature produce and accumulate metabolites - extra mineral salts, thus, by performing the role of a kind of filter. Over time, sediments are becoming more and in the fall, the plant gets rid of the sheet, which ceases to benefit.
So established in nature, nothing disappears in vain. The fallen leaves are covered with the land from frost, protecting the soil. In the warm season, the carpet of the resistant soil gradually decomposes, heats up. Insects, bacteria and microorganisms are recycled by the resulting humus in nutrient soil for live plants, closing cycle in nature.
The sheet is the most important organ of the plant, its main function is photosynthesis, i.e. the synthesis of organic substances from inorganic. However, on the external structure, the leaves of plants differ different types. In the form of a sheet, it is often possible to determine what kind of plants it belongs. The diversity of the external structure of the leaves is mainly due to the fact that the plants are adapted to different conditions Life.
Plant leaves differ in size. The smallest leaves are less than a centimeter (moc., Ore). Huge leaves are characteristic of some tropical plants. So W. aquatic plant Victoria Diameter Leaves is greater than meter.
In external structure the leaves of most plants allocatesheet plate and cherchok. In the leaf plate there is a predominantly photosynthetic fabric, and the petiole serves to connect the sheet plate with the stem. However, some types of plant leaves do not have stuffs. Leaves with cherry Characterized for most trees (maple, linden, birch, etc.). Leaves without Cherchekov characteristic of aloe, wheat, corn, etc.
With the external inspection of the sheet on it, the so-called are clearly visible vein. Better they are visible on the bottom of the sheet. The veins are formed by conductive beams and mechanical fibers. The conductive tissue moves from the roots of water and minerals, and in the opposite direction, from leaves, organic substances. Mechanical tissue gives the leaves strength and rigidity.
For parallel housing The veins in the sheet plate are located in parallel to each other and look like straight lines.
For arc hillovanya The location of the veins is similar to parallel, but the farther from the central axis of the sheet plate, the greater the vein has an arc shape, and not direct.
Parallel and arc housing is characteristic of many monocotyledonic plants. So many cereals (wheat, rye) and onions have parallel housing, and the valley is arc.
For mesh residents Allows in the sheet form a branching network. Such a dwelling is characteristic of many bipartite plants.
There are other types of leaf housing.
Simple and complex leaves
Depending on the number of sheet plates on one cut, the leaves are divided into simple and complex.
W. simple leaves On one cut, only one sheet plate (birch, aspen, oak) is developing.
W. complex leaves A few or many sheet plates are growing from one total of a tube; At the same time, each such leaf has its own little petiole, which connects it with a shared cushion. Examples of plants with complex leaves are rowan, acacia, strawberries.
Location of leaves
On the stalk of the plant allocate nodes and interstices. The leaves are growing from the nodes, and the interdosezium is sections of the stem between the nodes. The location of the leaves on the stem may be different depending on the type of plant.
If the leaves are located one by one in the nodes, while all the leaves together give the type of location as it were on the spirals along the stem, then they talk about another location of the leaves. This location is characteristic of sunflower, birch, rosehip.
For opposed location The leaves grow two in each node, opposite each other. The opposite location occurs in maple, nettle, etc.
If more than two leaves grow in each node, then they talk about mutivated leaf spot. It is peculiar, for example, for Elaus.
There is also otset location of leavesWhen there are almost no interstice, and all the leaves grow as it were from one place in a circle.