Calyx (lat. Calyx) - the outer circle of a double perianth, consisting of sepals, which in most cases are green. In many dicotyledonous plants, the calyx has four or five sepals, but in the flowers of some plants there are two or very many. a large number of. The calyx protects the developing parts of the flower in the early stages, that is, before the opening of the bud, and the sepals take part in photosynthesis.

A calyx was formed from modified upper bracts. Sepals are similar to vegetative leaves, only they have simple form, small size and green color. In addition, located on the receptacle, the sepals continue the spiral that the vegetative leaves form, and they, in turn, form gradual transition to sepals, for example, in calicant and dillian families, some types of peony. The sepals consist of the main parenchyma - the mesophyll with loose tissue through which conductive bundles pass, and the epidermis - the integumentary tissue.

Cups are divided into:

1. Divided.

2. Joint-leaved.

Structure

At the split-leaved calyx (buttercup, cabbage, cherry) sepals are located freely at a distance from each other.

At the calyx (tobacco, peas, potatoes) sepals fully or partially fused. It consists of a calyx tube, teeth (lobes) and lobes, depending on the degree of fusion of the sepals, and their number corresponds to the number of sepals. According to the shape of the tube, joint-leaved calyxes can be: funnel-shaped (raffiolepis umbrella), bell-shaped (some yasnotkovye) and tubular (kalanchoe, tubular). If the calyx is divided into two unequal parts (lips), then it is called two-lipped (skull, sage, bean). In some plants, the sepals form two circles (mallow, raspberry, strawberry). The outer circle in such a calyx is called the subcalyx and its leaflets are homologous to stipules.

During the blooming or flowering of a flower, the calyx may fall off (poppy family) or bend back and become inconspicuous. Often the calyx changes after flowering and serves to distribute fruit and seeds. So they turn into a box with fruits inside (yasnotkovye), or into a tuft with seeds, due to which they are easily carried by the wind (aster). In addition, the calyx with fruits may have serrated bristles, with which it clings to animal hair and people's clothing, and distribution occurs. In some cases, instead of green, the calyx has a bright color and functions as a corolla, which is often reduced to nectaries (larkspur, aconite, hellebore). In other cases, the calyx is poorly developed (umbellate, Compositae, Valerian).

Due to the variety of biological functions that sepals perform, a wide variety of morphological modifications of these flower structures are observed in nature.

The section is very easy to use. In the proposed field, just enter the desired word, and we will give you a list of its meanings. It should be noted that our site provides data from different sources- encyclopedic, explanatory, derivational dictionaries. Here you can also get acquainted with examples of the use of the word you entered.

The meaning of the word cup

cup in the crossword dictionary

Dictionary of medical terms

Explanatory dictionary of the Russian language. D.N. Ushakov

cup

cups, w.

Reduce-caress. to a cup. Coffee cup. - Have another cup! - No, please! A. Ostrovsky.

The outer covering of the flower, usually green, protects the flower from harmful effects during its ripening, in a state of bud (bot.).

Explanatory dictionary of the Russian language. S.I. Ozhegov, N.Yu. Shvedova.

New explanatory and derivational dictionary of the Russian language, T. F. Efremova.

Encyclopedic Dictionary, 1998

cup

in botany, the outer part of a double perianth, consisting of sepals. Protects the bud.

Cup

(calyx), a set of outer tepals (sepals) surrounding the corolla in flowers with a double perianth. The sepals are usually green, free or fused with each other (separate or joint-leaved C.). Biological significance Ch. ≈ protection internal organs flower and developing fetus, as well as providing it with additional nutrition. In a few plants (hydrangea, heather, some ranunculaceae), the Ch. is large, brightly colored and serves to attract insects instead of the corolla, which in this case is absent or underdeveloped; in some plants, the Ch. falls off when the flower blooms (for example, in the poppy), in others, after it has faded (for example, in the buttercup); in most plants, however, it remains after flowering, sometimes it even grows and can take part in the formation of the fruit. In Umbelliferae, Compositae, and some other plants, Ch. is reduced completely or turns into hairs.

Wikipedia

Cup

Cup- a set of sepals, most often painted green, forming one or more outer circles of a double perianth. The number of sepals in a flower varies from two (poppy family) to an indefinite number (tea family), but most dicots often have four or five.

Examples of the use of the word cup in the literature.

Juliette, bending down, hands me cup I'll tell you, and I can't help but glance at her cleavage.

In addition, scented sealing wax, scented writing paper, love letter ink scented with rose oil, Spanish leather pads, white sandalwood nib cases, pots and cups for flower petals, brass incense burners, crystal bottles and flasks with ground amber stoppers, smelly gloves, handkerchiefs, pincushions stuffed with nutmeg, and musk-soaked wallpaper that could fill a room with fragrance for more than a hundred years.

Yesenin sat next to him on the sofa and, like a wooden ball of cups bilbock dropped his head from his shoulders into his hands.

But when you are practicing mindfulness, you may naturally want to take time to slow down your pace, such as quietly doing some gardening, having a quiet drink. cup coffee, leisurely walk, slowly wash the dishes, etc.

All this is extremely interesting, and I admit that you can already see how my mouth foams before a seizure - but no, nothing foams, I just release multi-colored fleas of happy thoughts into the appropriate cup.

Pink and blue salons with high ceilings, with air conditioning, like we have in Friedrich's Grunwald house, with drinking bowls on coasters - so that, God forbid, the Kitty or Dog would not have to bend low over cup!

When Vladimir Vladimirovich settled down on the sofa, Drongo brought him cup coffee.

On the street, right along the sidewalk, green and crimson carpets were spread out, light tables stood on them, and cheerful people sat on openwork chairs at the tables, they drank coffee from tiny cups, wine from tall glasses, but I was especially struck by a huge beer mug - twice the size of my, also not small, Dulevo container.

On the walls are low conical white hats made of birch bark, almost a arshin in diameter, with black and red applications 70 made of birch sapwood, leather and wooden shields, old wooden armor covered with lacquer, spears with bamboo shafts and steel tips almost a foot long, pipes with long bamboo mouthpieces and small copper cups, pouches and pouches made of deer skin, boots and jackets made of seal skins that resembled yellow velvet, a dressing gown made of fish intestines, similar to bulging parchment paper, dotted with seams, like a tattoo.

Jumping up impetuously, Georgy opened the door a crack and, having accepted from Erasti a tray of coffee cups, lowered on again closed door a heavy curtain thickly woven with stars.

Ritual candles stood in a row on a twisted copper stand in a row. cups red and blue glass.

Staremberg grimaced, was about to object that many Austrians in their lives, perhaps, had not drunk and cups coffee, with the possible exception of the emperor himself and his family, and therefore Kulchitsky is unlikely to have any benefit from this gift.

Instead of leaves, the flower had wings, also two shaggy wings in a weak, childlike feather, and a shaggy stalk, as if covered in a jacket, propped up cup a flower, a thin, transparent ice flickered in the calyx.

As soon as Lina left the kitchen, dad quietly sneaked in to have a quiet drink. cup coffee before Emil wakes up.

Ten minutes before the start the protagonist press conference Al Pocino asked cup coffee, and Gard ordered Martens to prepare the drink himself and, before giving it to the gangster, allowed him.

Origin

The calyx arose in the process of evolution in most cases as a result of concentration around the flower and modification of the upper bracts.

Sepals are similar to vegetative leaves, but their structure is simpler: they usually small sizes, simple in shape and have a green color, due to which they photosynthesize. Consist of the main parenchyma, often called the mesophyll, which is penetrated by vascular bundles, the integumentary tissue is the epidermis. In the parenchyma, in combination with conductive elements, lactic cells can occur. The mesophyll of the sepals is composed of more or less isodiametric cells that form loose tissue. The epidermis of the sepals is characterized by the development of stomata, trichomes, and the deposition of cutin in the cell walls.

Classification

The cup may be single-leaved, consisting of free sepals (cabbage, ranunculus, cherry), and joint-leaved when the sepals partially or completely grow together over a greater or lesser extent (tobacco, peas, potatoes).

In the calyx, the calyx tube, teeth (lobes) and lobes are distinguished depending on the degree of fusion of the sepals, the number of which corresponds to the number of sepals.

Depending on the characteristics of the tube, that is, the fused part of the calyx, there are tubular(kalanchoe, tubular), bell-shaped(some Lamiaceae) and funnel-shaped(Raphiolepis umbellata) calyx.

The calyx is called two-lipped, if it is divided into two unequal parts, each of which is called lip(skullcap, sage, beaver).

Sometimes the calyx has two circles of sepals (strawberry, mallow, raspberry) - in this case, the outer circle is called subcup. Subcup leaflets are homologous to stipules.

Functions

The main function of the calyx is to protect the developing parts of the flower in the early stages of its formation; that is why the outer covers of the bud before it blooms in flowers with a double perianth are formed by a calyx. When the flower blooms or during flowering, the calyx sometimes disappears (poppy family) or folds back and becomes inconspicuous.

Often, at the end of flowering, the calyx is able to change, while acquiring new functions, mainly related to the distribution of fruits and seeds. For example, in Lamiaceae, the calyx serves as a receptacle for a fractional fruit, while in Asteraceae it turns into a tuft (pappus), which facilitates the transfer of fruits by the wind. Sometimes on the calyx there are characteristic serrated bristles, with which the fruits cling to the hair of animals and people's clothing and are carried.

The calyx is usually green, but sometimes acquires a bright color and acts as a corolla, which in this case is often reduced to nectaries (larkspur, aconite, hellebore). In some cases, the calyx is poorly developed (umbellate, Compositae, Valerian).

calyx in flower formula

In the flower formula, the characteristic of the calyx comes after the indication of the symmetry of the flower and is denoted literal expression Ca (lat. calyx) or K next to which the numbers indicate the number of elements, for example: Ca 5 - double perianth: calyx of 5 sepals. If the sepals are fused, then in the flower formula the number of fused elements is taken in brackets, for example: Ca (5) .

Literature

• Biological Encyclopedic Dictionary / Ch. editor M. S. Gilyarov. - M: "Great Russian Encyclopedia", 2003. - S. 709. - ISBN 5-85270-252-8

• Yakovlev G.P., Chelombitko V.A. Botany: Textbook for universities / Ed. R.V. Camelina. - St. Petersburg: SpetsLit, from SPHFA, 2003. - S. 188-189. - ISBN 5-299-00237-8

• Andreeva I.I., Rodman L.S. Botany. - M: KolosS, 2005. - S. 325 - 326. - ISBN 5-9535-0114-1

• Barabanov E.I., Zaichikova S.G. Botany: textbook for students. higher textbook establishments. - M: Ed. Center "Academy", 2006. - S. 193-194. - ISBN 5-7695-2656-4

Wikimedia Foundation. 2010 .

Synonyms:

See what "Cup" is in other dictionaries:

calyx, sepals of a flower, taken as a whole. The calyx has a green color, its purpose is to protect the flower at the bud stage. When the flower opens, the calyx surrounds its carpels, PETALS and STAMENS and forms the outer RING of the perianth... Scientific and technical encyclopedic dictionary

CUP, cups, for women 1. reduce caress to a cup. Coffee cup. “Have another cup! No, please! A. Ostrovsky. 2. The outer cover of the flower, usually green, protecting the flower from harmful effects during its ripening period, in ... ... Dictionary Ushakov

CUP, and, wives. 1. see cup. 2. The outer green cover of the flower that protects the bud (special). 3. In general, an object that has the shape of a hemisphere. H. call. Cup cap. The patella is the patella. Explanatory dictionary of Ozhegov. S.I. Ozhegov, N.Yu ... Explanatory dictionary of Ozhegov

In botany, the outer part of a double perianth, consisting of sepals. Protects the bud... Large encyclopedic Dictionary

- (calyx), the outer part of the double perianth, usually green. It can be dividing if the sepals that form it are free and joint-leaved, in which a tube and teeth are distinguished. Main the function of protecting other parts of the flower, in connection with which Ch. ... ... Biological encyclopedic dictionary

Exist., number of synonyms: 9 ancilina (2) valonea (2) demitass (2) ... Synonym dictionary

AND; pl. genus. check, date chkam; well. 1. Reduce. to the cup. Coffee tea. Eat a cup of soup. Break a cup. Bring a cup of jam. 2. Nerd. Part of the perianth, consisting of separate or fused corolla sepals that protect the corolla ... ... encyclopedic Dictionary

cup- taurelė statusas T sritis augalininkystė apibrėžtis Išorinė augalų žiedo dalis, sudaryta iš taurėlapių. atitikmenys: engl. calyx rus. cup ... Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

- (calyx) a set of outer tepals (sepals) surrounding the Corolla in flowers with a double perianth. The sepals are usually green, free or fused together (separately or joint-leaved). The biological significance of Ch. ... ... Great Soviet Encyclopedia

Hello, friends!
I continue a series of posts about the structure of a flower. Today we will talk about the integument of the flower - the calyx and corolla, which form the perianth. The main role of the integument of the flower is to protect the pistils and stamens, as well as to attract pollinators.

FLOWER COVERS
(Astrakhantseva O.A.)

Flower cover -
Cloak of petal silk,
Warm cloak lining -
Sepal squad.

Petals form a corolla
It is changeable in color and shape.
Attracts with aroma
Nosed pollinators.

Sepals - palms
Hug the flower stalk
They make a cup
And the buds protect.

Goal like a falcon

Sometimes the perianth of the flowers may be absent. For example, ash, poplar, such flowers, pollinated by the wind. Which is not surprising. The presence of a cup or petals would only prevent the wind from carrying pollen. After all, the trees are blooming in early spring before the leaves open. We could see it with our own eyes, watching the cut branches.

If you have not done such experiments yet, then you need to hurry up and go on a winter excursion for the harvest of twigs. All links to the blog article series about twigs are presented HERE - http://biomagic27.blogspot.com/2015/12/blog-post_22.html

The willow, pollinated by insects, also does not have a perianth.

Flowers without a perianth are called achlamides. Chlamys in Ancient Greece called a woolen cloak. The prefix "A" means negation, absence. It turns out that achlamid flowers without clothes flaunt, for which they are also called naked.

Sometimes only female flowers are achlomid, while male flowers have a perianth. For example, at the birch.

ACHLAMYD FLOWER
(Astrakhantseva O.A.)

No whisk, no cup,
No dress, no shirt.
Goal like a falcon is such a flower,
Its barrel is open to the winds.

The structure of the perianth

To protect the pistil and stamens, parts of the plant, different in origin, were transformed into new structures. Leaves under the flower, gathered around FLOWER and turned into sepals. From them emerged a cup. The calyx protects the bud before it opens, and in some cases even after.

And the sterile stamens, devoid of anthers, increased in width and turned into corolla petals. Although in fairness, it is worth noting that in certain cases the leaves also turned into petals, but much less often.

Various pigments (CAROTENES and ANTHOCYANES) began to accumulate in the vacuoles of the petal cells, giving a bright color.A cycle of games and experiments with the study of color pigments with fairies is presented in my book RAINBOW FAIRY LABORATORY which can be downloaded for free.

This is how the corolla was formed, which not only protects the pistil and stamens, but also attracts pollinators.Despite the fact that the petals are thinner and more delicate structures, they warm well because they contain air cavities. This is easy to verify by doing a simple EXPERIMENT WITH A SYRINGE.

Double perianth at Khatma

If the flower has both a calyx and a corolla, then such a perianth is called double.. Many plants have just such flowers - peas, petunias, cabbages, phloxes, wild roses and roses.

perianths
(Astrakhantseva O.A.)

If the cup and whisk
We see with you
That is such a perianth
Let's call it DOUBLE.

A SIMPLE perianth -
Lightweight guy.
Cup or whisk only
He has a flower.

If the flower has only sepals or only petals, then it is a simple perianth. Based on what a simple perianth is represented, its corolla and calyx shape is distinguished.

Tulip simple corolla

corolla simple perianth consists only of petals. Common in monocot plants. For example, a tulip, a lily, a goose onion. characteristic of insect pollinated plants. In plants with a corolla simple perianth, the petals are denser, and often covered with wax.

The calyx simple perianth is represented only by sepals. These are inconspicuous green flowers that have switched to wind pollination as a primary or secondary method, combining wind and insect pollination. They don't need a whisk. Characteristic for beets, quinoa, nettle, hemp, sorrel.

The structure of the calyx

The sepals are collected in a whorl. The receptacle is surrounded by a ring, thus forming a cup. Sometimes the calyx is double, that is, it contains two whorls of sepals. For example, strawberries and mallows. The lower circle of the sepals of the double calyx is called the subcalyx.

The number of sepals is a systematic feature and remains unchanged in most plant species. For example, an apple, cherry, plum flower has 5 sepals.

These plants have the calyx is separate-leaved, that is, all the sepals lie separately from each other, freely, not fused.

A separate-leaved calyx is characteristic of cabbage flowers, buttercup.

Often the sepals persist after the flower has fallen and are involved in fruit dispersal. Either as a flying structure, or as a bright element that attracts seed distributors to the fruit. For example, in petrea climbing, the dried stars of the calyx help the seeds in flight.

ATTENTION! Sometimes the sepals fall off when the flower blooms, for example, in poppies.In order not to be trapped, it is better to set the number of sepals on an unopened bud.

If the sepals are completely or partially fused together, then the calyx is called cleavage or joint-leaved.

In this case, a tube and teeth are isolated in the structure of the calyx. The number of teeth matches the number of sepals, so we can tell how many fused sepals the calyx consists of.

Peas, fragrant tobacco, and potatoes are among plants that have a sprout-leaved calyx in flowers.

Fragrant tobacco

Sepals turned into petals

Sometimes the calyx becomes brightly colored and takes over the functions of the corolla, attracting pollinators. And the petals turn into small nectaries. For example, this is typical for the buttercup family, for hydrangeas.

In the hellebore, the sepals have changed into petals. Why do bright sepals need a plant that blooms when pollinators in their mass have not yet woken up? The snow hasn't melted yet, it's cold outside. The hellebore has nectaries. And nectar is a very costly production, the plant will not start it just like that. Try to solve this hellebore puzzle, and write in the comments.

Larkspur high

Larkspur tall has 5 bright blue sepals, and the petals have turned into small nectaries. The upper sepal has developed into a spur - a bag that contains nectaries inside. Outside, the bag is greenish.

In late May - early June, the alpine belt of East Kazakhstan blooms with orange frying or bathing suits. Related species bloom throughout the alpine belt of Europe. This is the favorite flower of the trolls.
Bright yellow and orange balls are formed by sepals that act as a corolla. The petals have turned into thin nectaries.

Asian bathing suit

In some plants, colored sepals complement the bright corolla. For example, fuchsia and orchids.
In orchids, the sepals are called sepals, they are the same size, and resemble petals.

Tasks for the research diary

And again, you are waiting for tasks from fairies for a young naturalist. Tasks are designed for early spring.

1. Try to solve the hellebore puzzle. Why does the hellebore need bright sepals if it blooms when the insects have not yet woken up? Watch spring in the garden or in the park behind the hellebore. AT middle lane it blooms in March. Do insects visit its flowers? Pay attention to the color at the base of the sepals - petals, how their inner and outer surfaces are colored. Record the start and end times of flowering.

PS: Hellebore is a poisonous plant, like most plants from the ranunculus family. Therefore, you should not collect it in bouquets, it is better to limit yourself to non-contact observation.

2. Pay attention to what perianth they have flowering plants. Try to notice which plants are more - with a double or a simple perianth? Is there a difference in their ratio between decorative and wild plants? Make a similar comparison in spring, summer and early autumn in the same place. Will this ratio change depending on the season? Enter the data in a spreadsheet.

3. Find plants with achlamid flowers (willow, poplar, sedge). Examine them under magnification under a magnifying glass. Draw what you saw. Make a photo collection.

4. Pay attention to the plants in which the calyx has become brightly colored - delphinium, larkspur, bathing suit, hellebore, hydrangea, replacing the petals.

Pay attention to the sepals, which complement the petals with a bright color. For example, on large-flowered abelia. its white flowers contrast with the red calyx. And when the flowers fall, a bright red calyx remains on the plant.

Among indoor plants pay attention tobright orchid sepals,fuchsia and its white, red or pink calyx.
Liana Petrea curly has star-shaped blue sepals that remain after the fall of the purple flowers.
Record your findings in your observation diary.

5. Compare the structure and thickness of the petals in the double perianth corolla and in the simple corolla perianth. Record the observations in your research diary.

And now a surprise from the fairies! Read about a CUP OF RED TEA in the article about hibiscus.

Next in line in this series is a story about a whisk.
If you liked it, tell your friends about the Biology Magic blog. Let there be more people who are not indifferent to wildlife.

A flower is a conspicuous, often beautiful, important part of flowering plants. Flowers can be large and small, brightly colored and green, odorous and odorless, solitary or collected together from many small flowers into one common inflorescence.

A flower is a modified shortened shoot that serves for seed reproduction. The flower usually ends on the main or side shoot. Like any shoot, a flower develops from a bud.

flower structure

The flower is a reproductive organ angiosperms, consisting of a shortened stem (flower axis), on which the flower cover (perianth), stamens and pistils, consisting of one or more carpels, are located.

The axis of the flower is called receptacle. The receptacle, growing, takes different shape flat, concave, convex, hemispherical, cone-shaped, elongated, columnar. The receptacle at the bottom passes into the pedicel, connecting the flower with the stem or peduncle.

Flowers that do not have a pedicel are called sessile. On the pedicel of many plants there are two or one small leaves - bracts.

flower cover - perianth- can be divided into a cup and a corolla.

Cup forms the outer circle of the perianth, its leaves are usually relatively small in size, Green colour. Distinguish between separate and joint-leaved calyx. Usually it performs the function of protecting the inner parts of the flower until the bud opens. In some cases, the calyx falls off when the flower blooms, most often it remains during flowering.

The parts of the flower located around the stamens and pistil are called the perianth.

The inner leaves are the petals that make up the corolla. The outer leaves - sepals - form a calyx. The perianth, consisting of a calyx and a corolla, is called double. Perianth, which is not subdivided into corolla and calyx, and all the leaves of the flower are more or less the same - simple.

Corolla- the inner part of the perianth, differs from the calyx in bright color and larger size. The color of the petals is due to the presence of chromoplasts. Distinguish separately - and joint-petal corollas. The first consists of individual petals. In interpetal corollas, a tube and a limb perpendicular to it are distinguished, having a certain number of teeth or vanes of the corolla.

Flowers are symmetrical and asymmetrical. There are flowers that do not have a perianth, they are called naked.

Symmetrical (actinomorphic)- if many axes of symmetry can be drawn through the whisk.

Asymmetrical (zygomorphic)- if only one axis of symmetry can be drawn.

Double flowers have an abnormally increased number of petals. In most cases, they result from the splitting of the petals.

Stamen- part of a flower, which is a kind of specialized structure, which forms microspores and pollen. It consists of a filament, through which it is attached to the receptacle, and an anther containing pollen. The number of stamens in a flower is a systematic feature. Stamens are distinguished by the method of attachment to the receptacle, by the shape, size, structure of the stamen filaments, connective and anther. The collection of stamens in a flower is called the androecium.

filament- the sterile part of the stamen, bearing an anther on its top. The filament can be straight, curved, twisted, winding, broken. In shape - hairy, cone-shaped, cylindrical, flattened, club-shaped. By the nature of the surface - naked, pubescent, hairy, with glands. In some plants, it is short or does not develop at all.

Anther located at the top of the staminate filament and attached to it by a ligament. It consists of two halves connected by a link. Each half of the anther has two cavities (pollen sacs, chambers, or nests) in which pollen develops.

As a rule, the anther is four-celled, but sometimes the partition between the nests in each half is destroyed, and the anther becomes two-celled. In some plants, the anther is even single-celled. It is very rare to see trinity. According to the type of attachment to the filament, the anthers are fixed, mobile and swinging.

Anthers contain pollen or pollen grains.

The structure of the pollen grain

The dust grains formed in the anthers of the stamens are small grains, they are called pollen grains. The largest ones reach 0.5 mm in diameter, but usually they are much smaller. Under the microscope, you can see that the dust particles different plants are not at all the same. They differ in size and shape.

The surface of the dust grain is covered with various protrusions, tubercles. Getting on the stigma of the pistil, pollen grains are held with the help of outgrowths and a sticky liquid released on the stigma.

The nests of the young anther contain special diploid cells. As a result of meiotic division, four haploid spores are formed from each cell, which are called microspores for their very small size. Here, in the cavity of the pollen sac, microspores turn into pollen grains.

This happens as follows: the microspore nucleus is divided mitotically into two nuclei - vegetative and generative. Around the nuclei, areas of the cytoplasm are concentrated and two cells are formed - vegetative and generative. On the surface of the cytoplasmic membrane of the microspore, a very strong shell is formed from the contents of the pollen sac, insoluble in acids and alkalis. Thus, each pollen grain consists of vegetative and generative cells and is covered with two shells. Many pollen grains make up the pollen of a plant. Pollen matures in the anthers by the time the flower opens.

pollen germination

The beginning of pollen germination is associated with mitotic division, as a result of which a small reproductive cell is formed (sperms develop from it) and a large vegetative cell (a pollen tube develops from it).

After the pollen in one way or another gets on the stigma, its germination begins. The sticky and uneven surface of the stigma helps to retain pollen. In addition, the stigma releases a special substance (enzyme) that acts on the pollen, stimulating its germination.

The pollen swells, and the restraining influence of the exine ( outer layer shell of the pollen grain) causes the contents of the pollen cell to break one of the pores, through which the intina (the inner, poreless shell of the pollen grain) protrudes outward in the form of a narrow pollen tube. The contents of the pollen cell pass into the pollen tube.

Under the epidermis of the stigma is loose tissue into which the pollen tube penetrates. It continues to grow, passing either through a special conductive channel between the mucilaginous cells, or tortuously along the intercellular spaces of the conductive tissue of the column. At the same time, a significant number of pollen tubes usually advance simultaneously in the column, and the “success” of one or another tube depends on the individual growth rate.

Two sperm and one vegetative nucleus pass into the pollen tube. If the formation of spermatozoa in the pollen has not yet occurred, then the generative cell passes into the pollen tube, and here, by its division, sperm cells are formed. The vegetative nucleus is often located in front, at the growing end of the tube, and sperm cells are successively located behind it. In the pollen tube, the cytoplasm is in constant motion.

Pollen is rich in nutrients. These substances, especially carbohydrates (sugar, starch, pentosans) are intensively consumed during pollen germination. In addition to carbohydrates chemical composition pollen includes proteins, fats, ash and an extensive group of enzymes. Pollen contains a high content of phosphorus. Substances are in the pollen in a mobile state. Pollen easily transfers low temperatures up to - 20Сº and even lower, for a long time. High temperatures quickly reduce germination.

Pestle

The pistil is the part of the flower that forms the fruit. It arises from the carpel (a leaf-like structure that carries the ovules) after the fusion of the edges of the latter. It is simple if it is composed of one carpel, and complex if it is composed of several simple pistils fused together by the side walls. In some plants, the pistils are underdeveloped and are represented only by rudiments. The pistil is divided into ovary, style and stigma.

Ovary- the lower part of the pistil, in which the seed germs are located.

Having entered the ovary, the pollen tube grows further and enters the ovule in most cases through the pollen inlet (micropyle). Penetrating into the embryo sac, the end of the pollen tube bursts, and the contents pour out onto one of the synergids, which darkens and quickly collapses. The vegetative nucleus is usually destroyed before the pollen tube penetrates the embryo sac.

Flowers right and wrong

The tepals (simple and double) can be arranged so that several planes of symmetry can be drawn through it. Such flowers are called correct. Flowers through which one plane of symmetry can be drawn are called irregular.

Flowers bisexual and dioecious

Most plants have flowers that have both stamens and pistils. These are bisexual flowers. But in some plants, some flowers have only pistils - pistillate flowers, while others have only stamens - staminate flowers. Such flowers are called dioecious.

Plants monoecious and dioecious

Plants that develop both pistillate and staminate flowers are called monoecious. Dioecious plants - staminate flowers on one plant, and pistillate - on another.

There are species in which bisexual and unisexual flowers can be found on the same plant. These are the so-called polygamous (polygamous) plants.

inflorescences

Flowers are formed on shoots. Very rarely they are located alone. More often, flowers are collected in conspicuous groups called inflorescences. The beginning of the study of inflorescences was laid by Linnaeus. But for him, the inflorescence was not a type of branching, but a way of flowering.

In inflorescences, the main and lateral axes are distinguished (sessile or on pedicels), then such inflorescences are called simple. If the flowers are on the lateral axes, then these are complex inflorescences.

Inflorescence type	Inflorescence scheme	Peculiarities	Example
Simple inflorescences
Brush		Separate lateral flowers sit on an elongated main axis and at the same time have their own pedicels, approximately equal in length	Bird cherry, lily of the valley, cabbage
Ear		The main axis is more or less elongated, but the flowers are without stalks, i.e. sedentary.	Plantain, orchid
cob		It differs from the ear in a fleshy thickened axis.	Corn, calla
Basket		The flowers are always sessile and sit on a strongly thickened and widened end of a shortened axis, which has a concave, flat or convex appearance. In this case, the inflorescence outside has a so-called wrapper, consisting of one or many consecutive rows of bracts, free or fused.	Chamomile, dandelion, aster, sunflower, cornflower
Head		The main axis is greatly shortened, the lateral flowers are sessile or almost sessile, closely spaced to each other.	Clover, scabiosa
Umbrella		The main axle is shortened; lateral flowers come out, as it were, from one place, sit on legs of different lengths, located in the same plane or dome-shaped.	Primula, onion, cherry
Shield		It differs from the brush in that the lower flowers have long stalks, so that as a result the flowers are located almost in the same plane.	Pear, spirea
Complex inflorescences
Complex brush or panicle		Lateral branching axes depart from the main axis, on which flowers or simple inflorescences are located.	Lilac, oats
complex umbrella		Simple inflorescences depart from the shortened main axis.	Carrot, parsley
Complex spike		Individual spikelets are located on the main axis.	Rye, wheat, barley, wheatgrass

The biological significance of inflorescences

The biological significance of inflorescences is that the small, often inconspicuous flowers, collected together, become conspicuous, produce the most pollen, and better attract insects that carry pollen from flower to flower.

Pollination

In order for fertilization to occur, the pollen needs to land on the stigma of the pistil.

The process of transferring pollen from the stamens to the stigma is called pollination. There are two main types of pollination: self-pollination and cross pollination.

self pollination

During self-pollination, pollen from a stamen falls on the stigma of the pistil of the same flower. This is how wheat, rice, oats, barley, peas, beans, and cotton are pollinated. Self-pollination in plants most often occurs in a flower that has not yet opened, that is, in a bud, when the flower opens, it is already completed.

During self-pollination, germ cells formed on the same plant merge and, therefore, have the same hereditary characteristics. This is why the offspring resulting from the process of self-pollination are very similar to the parent plant.

cross pollination

With cross-pollination, the recombination of the hereditary traits of the paternal and maternal organisms occurs, and the resulting offspring can acquire new properties that the parents did not have. Such offspring are more viable. In nature, cross-pollination is much more common than self-pollination.

Cross-pollination is carried out with the help of various external factors.

Anemophilia(wind pollination). In anemophilous plants, the flowers are small, often collected in inflorescences, a lot of pollen is formed, it is dry, small, and when the anther opens, it is thrown out with force. The light pollen of these plants can be carried by the wind over distances of up to several hundred kilometers.

The anthers are located on long thin filaments. The stigmas of the pistil are wide or long, pinnate and protrude from the flowers. Anemophilia is characteristic of almost all grasses, sedges.

Entomophily(carrying pollen by insects). The adaptation of plants to entomophily is the smell, color and size of flowers, sticky pollen with outgrowths. Most flowers are bisexual, but maturation of pollen and pistils does not occur simultaneously, or the height of the stigmas is greater or less than the height of the anthers, which serves as protection against self-pollination.

In the flowers of insect pollinated plants there are areas that secrete a sweet fragrant solution. These areas are called nectaries. Nectaries may be in different places flower and have different forms. Insects, having flown up to the flower, are drawn to nectaries and anthers, and during the meal they get dirty with pollen. When an insect moves to another flower, the pollen grains carried by it stick to the stigmas.

When pollinated by insects, less pollen is wasted, and therefore the plant saves substances by producing less pollen. Pollen grains do not need to stay in the air for long and can therefore be heavy.

Insects can pollinate sparsely located flowers and flowers in calm places - in the forest thicket or thick grass.

Typically, each plant species is pollinated by several species of insects, and each pollinating insect species serves several plant species. But there are some types of plants whose flowers are pollinated by insects of only one species. In such cases, the mutual correspondence between the modes of life and the structure of flowers and insects is so complete that it seems miraculous.

Ornithophilia(pollination by birds). characteristic of some tropical plants with brightly colored flowers, abundant secretions of nectar, strong elastic structure.

hydrophilia(pollination with water). Observed in aquatic plants. The pollen and stigma of these plants most often have a filamentous shape.

bestiality(pollination by animals). These plants are characterized by large flower sizes, abundant secretion of nectar containing mucus, mass production of pollen during pollination. bats- flowering at night.

Fertilization

The pollen grain falls on the stigma of the pistil and is attached to it due to the structural features of the shell, as well as the sticky sugary secretions of the stigma, to which the pollen adheres. The pollen grain swells and germinates into a long, very thin pollen tube. The pollen tube is formed as a result of division of a vegetative cell. First, this tube grows between the cells of the stigma, then the style, and finally grows into the cavity of the ovary.

The generative cell of the pollen grain moves into the pollen tube, divides and forms two male gametes (sperms). When the pollen tube enters the embryo sac through the pollen passage, one of the sperm fuses with the egg. Fertilization occurs and a zygote is formed.

The second sperm fuses with the nucleus of the large central cell of the embryo sac. Thus, in flowering plants, two fusions occur during fertilization: the first sperm fuses with the egg, the second with the large central cell. This process was discovered in 1898 by the Russian botanist, academician S.G. Navashin and called it double fertilization. Double fertilization is typical only for flowering plants.

The zygote formed by the fusion of gametes divides into two cells. Each of the resulting cells divides again, and so on. As a result of multiple cell divisions, a multicellular embryo of a new plant develops.

The central cell also divides, forming endosperm cells, in which reserves accumulate nutrients. They are necessary for the nutrition and development of the embryo. The seed coat develops from the integument of the ovule. After fertilization, a seed develops from the ovule, consisting of a peel, an embryo, and a supply of nutrients.

After fertilization, nutrients flow to the ovary, and it gradually turns into a ripe fruit. The pericarp, which protects the seeds from adverse effects, develops from the walls of the ovary. In some plants, other parts of the flower also take part in the formation of the fruit.

Spore formation

Simultaneously with the formation of pollen in the stamens, the formation of a large diploid cell occurs in the ovule. This cell divides meiotically and gives rise to four haploid spores, which are called macrospores because they are larger in size than microspores.

Of the four formed macrospores, three die off, and the fourth begins to grow and gradually turns into an embryo sac.

Embryo sac formation

As a result of threefold mitotic division of the nucleus in the cavity of the embryo sac, eight nuclei are formed, which are clothed with cytoplasm. Cells without membranes are formed, which are arranged in a certain order. At one pole of the embryo sac, an egg apparatus is formed, consisting of an egg and two auxiliary cells. At the opposite pole there are three cells (antipodes). One nucleus migrates from each pole to the center of the embryo sac (polar nuclei). Sometimes the polar nuclei fuse and form the diploid central nucleus of the embryo sac. The embryo sac in which nuclear differentiation has occurred is considered mature and can accept sperm.

By the time the pollen and the embryo sac have matured, the flower opens.

The structure of the ovule

The ovules develop on inner sides walls of the ovary and, like all parts of the plant, are made up of cells. The number of ovules in the ovaries of different plants is different. In wheat, barley, rye, cherries, the ovary contains only one ovule, in cotton - several dozen, and in poppy their number reaches several thousand.

Each ovule is covered with a covering. At the top of the ovule there is a narrow channel - the pollen entrance. It leads to the tissue that occupies the central part of the ovule. In this tissue, as a result of cell division, an embryo sac is formed. Opposite the pollen entrance, there is an egg in it, and the central part is occupied by a large central cell.

Development of angiosperms (flowering) plants

Formation of seed and fruit

During the formation of a seed and a fetus, one of the sperm fuses with the egg, forming a diploid zygote. Subsequently, the zygote divides many times, and as a result, a multicellular embryo of the plant develops. The central cell, which has merged with the second sperm, also divides many times, but the second embryo does not appear. A special tissue is formed - the endosperm. The endosperm cells accumulate reserves of nutrients necessary for the development of the embryo. The integuments of the ovule grow and turn into a seed coat.

Thus, as a result of double fertilization, a seed is formed, which consists of an embryo, a storage tissue (endosperm) and a seed coat. From the wall of the ovary, the wall of the fruit, called the pericarp, is formed.

sexual reproduction

Sexual reproduction of angiosperms is associated with a flower. Its most important parts are stamens and pistils. They undergo complex processes associated with sexual reproduction.

In flowering plants, the male gametes (sperm) are very small, while the female gametes (ovules) are much larger.

In the anthers of the stamen, cell division occurs, resulting in the formation of pollen grains. Each pollen grain of angiosperms consists of vegetative and generative cells. The pollen grain is covered with two shells. The outer shell, as a rule, is uneven, with spines, warts, outgrowths in the form of a mesh. This helps the pollen grains to stick to the stigma of the pistil. The pollen of the plant, ripening in the anthers, by the time the flower opens, consists of many pollen grains.

flower formula

Formulas are used to conditionally express the structure of flowers. To draw up a flower formula, the following notation is used:

	A simple perianth, consisting of sepals or petals alone, its parts are called tepals.
H	Calyx composed of sepals
L	Corolla, composed of petals
T	Stamen
P	Pestle
1,2,3...	The number of flower elements is indicated by numbers
,	The same parts of a flower, differing in shape
()	fused parts of a flower
+	Arrangement of elements in two circles
_	Upper or lower ovary - a dash above or below the number that shows the number of pistils
	wrong flower
*	right flower
♂	Unisexual staminate flower
♀	unisexual pistillate flower
	Bisexual
∞	Number of flower parts greater than 12

Cherry blossom formula example:

*H 5 L 5 T ∞ P 1

flower diagram

The structure of a flower can be expressed not only by a formula, but also by a diagram - a schematic representation of a flower on a plane perpendicular to the axis of the flower.

Draw up a cross-sectional diagram of unopened flower buds. The diagram gives a more complete picture of the structure of a flower than a formula, since it also shows mutual arrangement its parts, which cannot be shown in the formula.