What is a fetus in biology. Types of plant fruits. Types of dry fruits

The term "fruit" appeared in 1705 and since then means edible or inedible fruits of trees, shrubs (before, all plant fruits were called vegetables). The product is one of the main components of the human diet, since, depending on the variety, it contains many vitamins and microelements. According to rough estimates, there are just over 2,000 fruits on the planet.

Passion fruit

An ancient tropical culture of the genus Passiflora, yielding oval fruits of yellow or dark purple color (when mature), growing on vines. Passion fruit is grown for its juice, which is often added to other fruit juices for flavor. Passion fruit is a yellow-orange or dark purple oval fruit that is about 6-12 cm in size. Fruits with smooth shiny skin are preferred, but sweeter with rough, cracked skin.

Medlar

tour. muşmula
it is a whole genus of plants, which includes almost 30 species. However, there are two main cultivated types of medlar: Germanic and Japanese. The Germanic medlar was known to mankind for more than 1000 years BC. In the territories of Ancient Babylon, Mesopotamia, it was freely traded, and it was transported by ships to the west to Ancient Greece and Ancient Rome. It was from here that the medlar came to European lands. Today, the Germanic loquat grows in the Balkans, Asia Minor, the Crimean mountains, Transcaucasia, Armenia, Algeria, Azerbaijan, Greece and northern Iran. The tree is quite picky and grows well only in dry, sunny places and on slightly acidic soil.

Nectarine

A fruit that is a peach with a smooth skin. Despite popular myth, nectarine is obtained by selection or simple mutation of peaches and is not a hybrid of a peach and a plum.
This classic example of a bud mutation occurred when peach trees self-pollinated. Nectarines sometimes appear on peach trees, and peaches on nectarine trees. Nectarines are first mentioned in 1616 in England.

Papaya

A short, slender tree with a thin, branchless trunk 5-10 meters high, crowned with an umbrella of finger-dissected leaves on long petioles. Papaya leaves are large, 50-70 centimeters in diameter. The flowers develop in the axils of the petioles, turning into large fruits, 10-30 cm in diameter and 15-45 cm long. Ripe papaya fruits are soft and have a color ranging from amber to yellow.

Peach

A tree of the Pink family, has the subgenus almond. It differs from almonds only in fruits. Leaves are lanceolate with a serrated edge and almost sessile, appearing before the development of the leaves, pink flowers. The fruit is a peach, spherical, with a groove on one side, usually velvety. The stone of the peach is wrinkly furrowed and with dotted dimples.

Pomelo

english pomelo
Citrus fruits of the eponymous evergreen tree. The peel of the fruit is quite thick, and the slices are large, separated by hard white partitions, with a bitter taste. Ripe broomsticks can range in color from light green to yellow-pink. Usually only one side acquires a pink color, which during maturation was turned towards the sun. The fruit holds the record for citrus fruits. Its diameter can be 30 cm, and its weight can reach 10 kg. The taste of the pomelo is very close to that of grapefruit, but the pulp is not so juicy and when peeled, the inner membranes are easier to separate from the edible part.

Orange

It is also called Chinotto or Bigaradia - it is a woody evergreen plant belonging to the Rutaceae family, a species of the genus Citrus. It is considered a hybrid of pomelo and mandarin. Fresh orange is considered inedible, and it is prized mainly for its zest. The peel is quite easily separated from the fruit, you just need to cut it into 4 parts. The zest of pomegranates is used for making desserts. It is also often added to ice cream. For such a dessert, you need to take the zest and juice of an orange, cream and sugar. All this must be whipped with a mixer and sent to freeze.

A body such as only angiosperms have fetuses (flowering) plants. It is formed in the place of a flower if pollination of the flower and subsequent fertilization of the egg in the ovule have occurred. A seed develops from the ovule, and the ovary of the pistil turns into a pericarp. However, other parts of the flower can also participate in the formation of the pericarp. The fruit is a pericarp with seeds enclosed in it.

In temperate climates, the fruits of plants usually ripen in summer and autumn.

The fruit is the organ for the propagation and protection of seeds. Since seeds can spread in different ways, there are many varieties of fruits. But still, the fruits of plants are classified by combining them into various groups.

So plant fruits are divided into dry and juicy... In juicy fruits, the pericarp contains juicy pulp. But dry fruits do not have it.

The succulent fruits are usually distributed by the animals that eat them. At the same time, the juicy pericarp is digested in the digestive tract, and the seeds leave the body with excrement. It is beneficial to plants. So their seeds are carried far enough away from the parent plant and do not compete with it for resources, and also receive fertilization.

Dried fruits are often adapted to be spread by wind and self-spreading. However, animals can also spread them. This happens with plants in which the fruit is a nut. For example, hazel nuts are often carried through the forest by squirrels and other rodents, which store for the winter. Animals forget about some of their reserves, and the seeds can germinate.

The most common juicy fruits are berries and drupes.

Have berries juicy pulp is covered with skin on the outside. The pericarp contains many small seeds. Berries include the fruits of currants, gooseberries, blueberries, tomatoes.

Have drupe there is also a juicy pulp covered with a thin skin. However, there is only one seed inside, and it is enclosed in a hard inner layer of the pericarp, which is called a bone. Drupes include cherries, plums, apricots.

The most common dry fruits of plants are caryopsis, bean, pod, achene and capsule.

Have weevil the pericarp is very thin. It looks like a film and grows together with the seed. There is only one seed in the fruit.

Beans consist of two valves, which open when ripe fruits. In this case, the dry leaves of the bean curl and when they crack, the seeds fly out of them with little force. The seeds of the pod are attached to the inner sides of the valves. Beans include the fruits of plants such as peas and beans, as well as a plant called bean.

Pods are double-leafed and bean-like. However, they have a septum inside the fetus. It is to her that the seeds are attached. The pods include the fruits of cabbage, radish, radish.

Achenes are fruits containing only one seed. Moreover, their dry pericarp does not grow together with the seed. It is located inside the pericarp quite freely. The most famous plant that has a seed-fruit is the sunflower (seeds).

Boxes contain numerous seeds. Such fruits have holes through which the ripe seeds spill out when the wind shakes the plants. The capsule fruit is observed in poppy and tulip.

Fruit (lat. Fructus) is a flower modified as a result of double fertilization. Formed from a single flower, it is intended for the propagation of angiosperms, and also serves for the formation, preservation and distribution of the seeds contained in it. Many fruits are valuable food products, raw materials for obtaining dyes, medicines, etc. The science that studies fruits is called carpology, and its section that studies the distribution of fruits and seeds is called carpoecology. In pharmacology, fruits are called any types of fruits, their fragments, and also fruit.

Structure

The fruit is formed mainly from the ovary, but different parts of the flower (calyx, perianth and stamens) can take part in its formation. The seeds are formed from the ovules. The wall (the so-called pericarp) is formed from the wall of the ovary. The pericarp consists of three layers: outer - exocarp or epicarp, middle - mesocarp and inner - endocarp, they are all well distinguishable. For example, consider a cherry fruit. It has an outer layer (exocarp) - thin leathery, middle (mesocarp) - edible juicy pulp, inner (endocarp) - a seed surrounded by a hard bone of petrified tissue. There are fruits in which the layers of the pericarp are difficult to distinguish, even with anatomical examination, this is due to the compression and deformation of cells during fetal maturation.

Development

The fetus develops after fertilization, but in some angiosperms the embryo of the seed develops in the absence of fertilization, i.e. by apomixis. The morphological basis of the fetus is the gynoecium, primarily the ovary. Other parts of the flower (calyx, perianth, stamens) most often dry out, and sometimes with the ovary also participate in the formation of the fruit, transforming into juicy or woody, sometimes filmy fragments.

The ovary undergoes the greatest changes, in which enhanced cell division occurs, which leads to an increase in its size, proliferation of the walls. After pollination, the plant changes the direction of movement of nutrient compounds towards developing fruits. For example, in herbaceous plants, almost all synthesized organic substances go to the development of seeds and fruits, while other plant tissues are depleted. After cessation of growth, the fruit begins to ripen, while chlorophyll and tannins decompose, pigments accumulate in the vacuoles, which determine the color characteristic of this species. The walls contain different substances: sugar, some vitamins, proteins, starch, fatty oils, etc.

A mature fetus is characterized by a combination of its inherent features. The fruit contains a seed, or seeds, which are attached to the pericarp or freely located in the fetal cavity, or are densely covered with a fleshy wall. The seeds provide the spread of the plant species in nature, although by weight the seeds belong to a smaller proportion of the fruit. After ripening, nutrients cease to flow into it, it no longer grows and over time the tissues undergo destruction and decay, freeing seeds. Seedless fruits are also found.

Depending on the species, the fruits have different shapes: spherical, pear-shaped, cylindrical, spiral, lenticular, wing-shaped, etc. The surface of the fruit can be rough, smooth, prickly, warty, etc. Sizes vary from 1mm to 1m.

Classification

According to the classification, fruits are divided into real or true, formed from an overgrown ovary, and false, in the formation of which other parts of the flower take part.

Among the true fruits, there are simple, formed exclusively from a pistil, and composite, complex, formed from a multi-member apocarpous gynoecium (rose hips, strawberries, strawberries, raspberries, etc.). Simple fruits are divided according to the consistency of the pericarp into juicy (with a juicy pericarp) and dry (with a dry pericarp).

Dry include:

- boll-shaped or polyspermous (poppy, dope, tulip, bob), nutty or single-seeded (walnut, hazel, hazelnuts), kernels (cereals), lionfish (maple), acorns (oak), achenes (sunflower).

A woman was created by nature in such a way that at least once in her life she can give the world a new person. The period of waiting and giving birth is the brightest and at the same time alarming time. But the expectant mother shouldn't worry in vain. She should know that a normal pregnancy is the key to the correct development of her child.

If a woman has a clear idea of \u200b\u200bhow the baby's body is formed throughout pregnancy, then it will be quite simple for her to do everything necessary to avoid the development of pathologies.

Should a woman know how her baby is developing?

Knowing how the intrauterine development of the fetus occurs by week, the expectant mother can correctly organize her nutrition and daily routine. Also, having full information about what changes are considered the norm, a woman will avoid a state of unreasonable anxiety.

Calculating the intrauterine development of the fetus by week, it should be noted that it lasts 40 of these calendar periods. In other words, a woman's pregnancy lasts 280 days. During this time, the child undergoes a complete process of formation and development of all organs and systems.

Doctors-gynecologists consider the intrauterine development of the fetus by weeks and by periods, of which there are two: embryonic and fetal.

The first lasts from the moment the egg is fertilized until the 8th week of pregnancy. During this period, after fertilization, an embryo is formed, which descends into the cavity and attaches to it. The fetal period lasts from the beginning of the 9th week until the moment of delivery. The embryo transforms into a fetus, develops and grows.

It is also common to divide pregnancy into trimesters:

• First trimester (1 - 12 weeks).
• Second trimester (13 - 27 weeks).
• Third trimester (28-40 weeks).

Now you can consider in more detail how the intrauterine development of the fetus occurs by week.

What happens during the embryonic period?

The most important of this developmental period is the formation of the embryo. Over time, he begins to take on the shape of a person. The embryo is formed from the moment the egg is fertilized. This usually occurs in the fallopian tube.

From the moment of fertilization of the egg, the development of the fetus begins.
By weeks of pregnancy, morula is formed in the first seven days. It is a multicellular organism, the prototype of the embryo. Morula attaches to the wall of the uterus, and the umbilical cord and outer membranes of the fetus are formed from its outer cells. The organs and tissues of the unborn child are formed from the cells that are located inside it.

What does a woman feel?

In the first week of pregnancy, a woman has a slightly increased body temperature, it is close to 37˚С. There are no hormonal changes in the body yet, but the expectant mother instinctively feels the changes taking place. From this moment on, a woman should be very careful about her diet and lifestyle, exclude bad habits and follow the doctor's recommendations.

Each expectant mother will be very interested in how the fetus develops by weeks of pregnancy. This information will help a woman prevent many dangerous conditions. The third week of pregnancy is alarming because it is during this period that there is the greatest risk of fetal rejection. The woman's immune system tries to reject the embryo. However, in response, a special protein is released that suppresses this protective reaction, and the unborn child has a great chance of survival.

What happens to the embryo in the first weeks of pregnancy?

This period is also characterized by the formation of the placenta. An unborn baby at three weeks is a ball with a diameter of 0.2 mm. But during this period, the lungs and respiratory organs, the cardiovascular system, the spinal cord and the brain are actively formed, and the baby's face and gender are also laid.
The woman begins to feel mood swings, drowsiness and fatigue, early toxicosis may occur.

Further development of the fetus (this is the fourth week of pregnancy) is very intensive. The unborn child forms three germ layers:

• endoderm - the basis for the development of internal organs;
• mesoderm - what the skeleton and bones will be formed from;
• ectoderm is a material for the formation of the nervous system.

The embryo already has a pulsating tube that turns into a heart. On ultrasound during this period, the heartbeat is heard. The respiratory organs, the brain continue to form, the face is more clearly visible. The embryo has limbs, and by the end of the week they are already bent. The embryo is located in the placenta and maintains contact with the mother through this organ.

His heart is already beating!

During this period, many women only find out about their pregnancy, especially if it is the first one. Having found out for herself this fact, the expectant mother is interested in the main question: how does the development of the fetus take place?

By weeks of pregnancy, this is the fifth calendar period. At this time, the embryo still has little resemblance to a person, but his heart is already beating, gender is clearly defined, kidneys, liver, pancreas and thyroid glands are being formed.

Already at the 8th week, the future baby acquires the outlines of a person, his height is 3-4 cm. He has already formed arms and legs, his forehead is clearly visible, the outlines of his eyes, lips and nose are outlined. Internal organs are actively formed and developed. The stomach is already capable of producing juice, the heart is formed, the intestines are growing, the trachea and bronchi have appeared. The spine, brain and limbs are actively developing.

By the end of the eighth week of pregnancy, the embryonic period of development ends, but the first trimester is still ongoing. The unborn child has already acquired a human form, the placental-uterine circulation has been formed.

Fetal period

This stage begins from the 9th week of pregnancy and lasts until the very birth. The fetal period is divided into two parts:

• early (9 - 28 weeks);
• late (29 - 40 weeks).

In the early fetal stage, fetal development continues. This is the ninth week of pregnancy. At this time, the growth of the fetus is 40-50 mm. He begins to be active: bends his arms and legs, turns his head, brings his fingers to his mouth. But my mother is not yet able to feel this, the fetus is still too small.
Outwardly, the future baby looks like a little man with a big head. The eyes are still closed and the skin is transparent. The genitals begin to form, and this process will continue for the 20th week. The cerebellum and pituitary gland develop. The heart has four chambers. The tail disappears, being replaced by the tailbone.

The embryo turns into a fetus

In the tenth week of pregnancy, the embryo is already called the fetus, and weighs 5 grams. In his photographs, isolated fingers, neck, elbows, knees, eyelids and upper lip are already visible.

The tongue has taste buds, the thickness of the umbilical cord increases.

The eleventh week of pregnancy is characterized by the further development of the fetus. He already has eyelashes and milk teeth. The rectum is formed. The spinal cord is already producing red blood cells. The intestines are ready to go.

Many mothers during this period are sent by a gynecologist for a planned ultrasound scan. Undergoing this procedure, women are interested in the main question: is the development of the fetus normal?

By the weeks of pregnancy, the twelfth period begins. During this period, the child has formed phalanges of fingers and earlobes, he opens and closes his eyes. The intestines are already contracting, and the liver is able to secrete bile. The baby's circulatory system is functioning, leukocytes appear.

At the twelfth week, the first trimester of pregnancy ends and the second begins.

The kid is actively growing

During this period, all systems of the fetus are formed, they are developing and growing. At the thirteenth week, which marks the beginning of the second trimester, the baby reaches 80 mm in length and weighs about 20 g. At this time, the fetus is intensively forming a skeleton, the pancreas begins to produce insulin.

The gynecologist will send the expectant mother to the first genetic study. After examining the results of the ultrasound, the doctor will be able to tell you how the intrauterine development of the fetus takes place by weeks of pregnancy, whether the indicators are normal.

At the 14th week, the child's face continues to form, facial expressions, eyebrows and hair on the head appear. On the body of the fetus, fluff and cheese-like grease form. The thyroid gland begins to work, its own hormonal background develops.
The excretory system is functioning, the child makes breathing movements.

In the antenatal clinic, you probably saw a stand showing the intrauterine development of the fetus by week.

A table with this kind of information will be useful to every woman.

At the fifteenth week of pregnancy, the child develops hearing, the intestines form the original feces, and the placenta thickens. The fruit weighs about 50 g and is 60 mm tall.

The expectant mother feels the first movements of the baby

The sixteenth week of pregnancy is marked by an increase in the volume of amniotic fluid. The child is actively moving, and the mother begins to feel it. Muscles are developed on the face and the child is characterized by facial expressions at this time. Bones and nails are almost completely formed, the skin is very thin and blood vessels are clearly visible through it.

During this period, the gynecologist directs the woman for a second genetic screening. For this, the expectant mother will have to undergo a second ultrasound scan. It clearly shows the intrauterine development of the fetus by week. Photos that can be taken at this stage are presented below.

We count fetal movements

From the 28th week of pregnancy, the third trimester begins, and from the 29th week - the late fetal period. At this time, the child is cramped in the womb, and his movements are not so active. Nevertheless, a woman should clearly track the tremors, their number should be at least 10 per hour. The brain is actively developing, and furrows appear on it. The teeth are covered with enamel, the eyes are capable of focusing. The baby's weight is about 1250 g, and his height is 37 cm.

At the 30th - 31st week of pregnancy, the baby already takes its final position in the uterus. The fetus is actively gaining weight by increasing muscle mass and subcutaneous fat. If a child is born during this period, he has every chance of survival.

The further intrauterine development of the child (this is the 32nd calendar period by weeks) is characterized by the improvement of the immune and nervous systems. The child has its own routine of waking and sleeping, it has its own temperament. The baby weighs 1800 g, and his height is 42 cm.

At the 33rd - 34th week of pregnancy, the baby actively trains the lungs, perceives the entire environment in full. The skin of the fetus becomes smooth, the bones of the skull harden.

The baby is preparing for birth

At 36 - 37 weeks of gestation, the fetus is preparing for birth. His mother’s stomach is already cramped for him and it’s more and more difficult to move.

His body has enough fat reserves for thermoregulation after birth, the lungs are ready to breathe. The fluff on the body is already absent, but the hair on the head and nails grow back.

At 38 - 40 weeks, all mothers are expecting childbirth. This can happen at any time. The baby sinks and it becomes easier for mom to breathe. The woman carefully monitors the discharge of the mucous plug and the appearance of contractions.

And now, finally, it happened! Mom and baby are now together. The crumb is still very small, but full of strength to learn the new world. Now his status is newborn.

Table of intrauterine development of the fetus by weeks of pregnancy

This article provides a complete description of how the intrauterine development of the child takes place by week. The table below will serve as a kind of conclusion to all of the above and will serve as a reminder for the expectant mother.

Of course, it is best to study this information when a pregnancy is just being planned. Then the woman has more chances to properly organize nutrition, regimen, intake of necessary vitamins and minerals. However, information about the intrauterine development of the baby will always be timely and interesting for the expectant mother, regardless of the length of her pregnancy.

In the world of flora, there is a group of plants (about 250 thousand species) capable of developing fruits. Their distinctive morphological feature is the presence of a flower, which is a generative organ. From all parts - ovary, corolla, pedicel, calyx with sepals - in the process of double fertilization, pericarp with seeds - fruits - develop.

The species of angiosperms differ among themselves in many ways, including different types of pericarp. Carpology is the branch of botany that studies fruits. The classification of fruits is carried out by a branch of biology called taxonomy. In this article, we will look at the main criteria used by scientists to determine the pericarp in angiosperms.

What is knowledge about the structure of fruits used for?

A description of the type of pericarp, as well as its external and internal structure, is a necessary condition, without which it is impossible to correctly determine to which family this or that flowering plant belongs. For example, the bean fruit is dry and open. It is characteristic only for plants of the legume family, for example, beans, peanuts, peas, alfalfa. Representatives of the Cereal family, belonging to the class Monocotyledonous, have a dry, unopened caryopsis fruit. That is why wheat, rye, barley are often called cereals. What needs to be paid attention to so that the classification of plant fruits is carried out correctly?

Features of the structure of the pericarp

So, only plants with flowers are capable of producing fruits. What is their structure? From above, the pericarp is covered with seed skin - exocarp. It is formed from the integuments of the seed bud. Further, the middle layer is located - the mesocarp. Let's dwell on its structure in more detail. If the cells of the middle layer contain a lot of water with mineral salts and glucose dissolved in it, it becomes fleshy, and the fruits in this case are called juicy, for example, cherries, plums, peaches. The last, inner layer of the pericarp, under which the seed lies, has a tough, woody texture and is called the endocarp. The structure of the pericarp is the main criterion by which the classification of fresh fruits in biology and agriculture is carried out.

What is stem fruit

Some plants contain not one, but several pistils at once. After fertilization, the same number of small fruits are formed, growing together as they ripen. So, raspberries and blackberries have complex pericarps - polydrupes. If the flower has one pistil (like cherry, apricot), then single simple fruits develop. The classification of fruits, adopted in botany, necessarily takes into account this criterion. Pineapple or mulberry flowers in inflorescences are located so close to each other that in the process of development, small fruits grow together. In figs, not only the flowers themselves, together with the receptacles, but also the axis of the inflorescence take part in the formation of the inflorescence. All the examples given describe juicy fruit, but there are also dry types. For example, in beet flowers, the perianths become stiff and woody, and then grow together, forming dry spherical compound fruits, consisting of 3 - 8 small fruits.

As you can see, angiosperms have simple and complex fruits. The classification of fruits allows botanists, together with other morphological characteristics (type of inflorescence, type of root system, shape of leaves and their position on the stem), to correctly determine which family the plant under study belongs to.

Types of juicy fruits

Berry crops such as black and red currants, gooseberries, widespread in the home garden, have a fleshy pericarp with a well-developed middle layer - the mesocarp. Their fruits are juicy berries. In an apple, quince, pear, a person uses a multi-seeded fruit for food - an apple, its pulp develops from an overgrown receptacle. Pumpkin is another type of juicy pericarp, but its outer cover does not look like a thin shell, but a hard layer consisting of mechanical tissue - sclerenchyma. In some plants, the pumpkin fruit has a cavity inside, filled with a placenta with seeds (melon, pumpkin). Other members of the Pumpkin family - watermelon, cucumber, zucchini, contain mesocarp, fused with the placenta and seeds. Plants belonging to the same family can have both similar and different fruits in their structure. The classification of fruits takes into account the peculiarities of the tissues of which all three membranes are composed: the skin, mesocarp and endocarp.

Why are fruits called dry?

If, during maturation, the middle layer of the pericarp loses water and grows together with the inner membrane, the fruit is called dry. Often for a person, practical interest lies in using not the fruits themselves, but only their seeds hidden under the pericarp, for example, in plants such as beans, peas, walnuts. Depending on the structure of the pericarp, there are non-opening and open-ended dry fruits. Taking into account the peculiarities of the development of the pericarp, the classification of fruits is carried out in the taxonomy of plants. Biology applies morphological and histological criteria in determining the type of pericarp, paying attention to the structure of the exo - and mesocarp.

Types of dry fruits

Plants of the legume family have opening polyspermous fruits: alfalfa, vetch, peanuts, peas. In cabbage, mustard, and rape, the fruits outwardly resemble beans, but they are not. Their name is a pod or pod, since the seeds are not attached to dry leaves, but develop on a special partition. Unbreakable dry single-seeded fruits are acorn, nut, achene, weevil. They are found in plants of the families Astrovye, Beech, Zlakovye.

In the article, we studied the classification of fruits and vegetables used to study angiosperms.