What is the bottom of an onion bulb. The structure of an onion bulb

02.12.201927.05.2017

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Introduction: problem, goal, tasks, hypothesis

1. From the history of the bow

2. The structure of the bulb

3. Whoever undresses him sheds tears

4. Using a bow

5. Bulb plants

6. Results, analysis, conclusions

Conclusion

Literature

Introduction

How often in life we do not pay attention to familiar things. But if you look closely, you can find out a lot of interesting things.

For example, onion. By the way, why onion? Mom says that onions are healthy, and often puts them in soups and salads. Grandma loves to bake pies with green onions. In the lessons of the world around us, we also talked about the benefits of onions. Yes, what a use! In the mouth - a fire, and from the eyes - a flood. All bow riddles end like this:

The grandfather is sitting, dressed in a hundred fur coats,

Whoever undresses him sheds tears.

So we thought, what is the onion for? And, in general, what is it? Botanists believe that the bulb is a stem with leaves that nature, at its whim, has slightly changed. Does not look like it? It turns out that a bulb for plants is like a backpack with groceries for us. And, if not for the rich supply of sweet juices in the bulb, then we could not have green onion in early spring. There have been many questions. We started our own research.

Target: study of onion bulbs.

Tasks:

1) learn the history of the appearance of onions on Earth;

2) find out how the bulb is arranged inside;

3) to observe the germination of the bulb under different conditions;

4) formalize the results of the study;

5) talk with experienced gardeners.

Object of study: bulb onions.

Subject of study: bulb - like an underground shoot.

Research hypothesis: if the bulb has a supply of nutrients, then under certain conditions (light, water, heat) it will germinate and sprout in the form of green feathers.

onion tear medicine plant

1. From the history of the bow

In books, we looked for information about onions and found out that the birthplace of this culture is Central Asia, Iran and Afghanistan. Gradually, the bow spread to nearby countries - India, China, Greece.

In Rus', this culture spread in the 12th - 13th centuries. The ancient Egyptians, when they built their pyramids, wrote down on their walls how many onions the workers ate. He gave the builders strength and health. The value of onions is determined by the presence of many useful substances. For example, it contains more sugars than apples and pears. Even hot onions contain up to 14% sugars. About 500 types of onions are known. 10 types of onions are listed in the Red Book and are under protection.

Onions are different. There are onions, batun, leeks, shallots, garlic, chives and others.

Onion the most common. This bow changes its name three times. Its seeds are called "black onion". From a black, like a coal, seed, a small onion grows. Onion - sevok. In the spring, the onion will be planted in the garden, it will get fat, it will become like a turnip. Hence the name - onion.

Bow-batun- perennial garden plant of the onion family, characterized by high tillering. In the onion - batun, the onion is barely noticeable, but its long leaves (they are called feathers) are green and fresh from spring to autumn. China and the south of Eastern Siberia are considered its homeland. It has other names: fistulous, sandy, Tatar, winter, Chinese onion, odorless garlic.

Leek- vegetable biennial spicy-aromatic plant, known and used by the ancient Egyptians, Greeks and Romans. Homeland consider the Eastern Mediterranean. The Romans were especially fond of leeks. The famous Nero used this bow with oil, believing that the bow gives special strength and sound to his voice.

Shallot very similar to green onions. Its bulbs are small, elongated, have a pronounced taste and smell compared to ordinary onions. The taste is delicate and soft. Shallots are high in potassium and low in sodium.

chives good because you can eat it in early spring, as soon as the snow melts. It can also be used for decorative purposes until late autumn. Used to create low borders. Onions - chives are an indispensable source of spring vitamins. Onions of this species are very small, collected in 15-20 pieces.

Garlic botanists describe it as a bulbous plant with a pungent taste

and strong smell. Garlic does not deteriorate for a surprisingly long time, retains freshness and moisture for months, unlike other vegetables, which dry out and decompose in just a few hours.

2. The structure of the bulb

In the encyclopedia we read:

"Loumkovitsa(lat. bülbus) - a modified, usually underground shoot of plants with a thickened short flat stem (bottom) and overgrown fleshy or membranous colorless leaf bases (scales), storing water and nutrients, also serving as an organ of vegetative reproduction. The membranous bulbs are covered with common membranous scales (onions). In the axils of the scales there are buds from which aerial shoots or daughter bulbs develop - kids»

And then they turned to the teacher of biology Silinskaya I.A. for help.

What is an onion? A house without windows and doors, a cunningly hidden bedroom, where onion buds, the beginnings of future shoots, sleep for the time being between juicy fleshy scales.

Outside, the walls of the onion children's bedroom are also covered with scales, only dry, golden. The thicker this golden cover, the longer the onion will be stored. The stronger the sleep of children.

3. "Whoever undresses him sheds tears"

They took onions and began to peel them. But what happened? Tears immediately appeared in my eyes. Why? By cutting the onion with a knife, we disturbed the rest of the onion buds - babies. The beast will fight for its cubs with claws and teeth. And how can an onion save its children? He has no claws or teeth. But the bow has a special, amazing weapon.

Arrows flew out of the cut bulb. At the slightest damage to the bulb, tiny droplets of juice are sprayed in all directions and fall into the eyes of a person. We could not see them - they are invisible, but felt - our eyes stung. We escaped with tears, our eyes remained intact. But if on the path of flying onion arrows there are carriers of diseases, harmful microbes, they will already be unhappy.

Chemistry teacher Fedorova T.V. talked about the chemical composition of the bulb. And we learned that onions emit a characteristic smell due to the presence of essential oils in it, including sulfur. Onion phytoncides kill microbes, streptococci - dysentery, diphtheria, tubercle bacilli, oral microflora, favorably affect kidney function. Onions provide health benefits. In addition, onions contain protein, sucrose, maltose, fructose, polysaccharide, proteins, ash, and fats. Onions are rich in vitamins C, A, D, B1, B2, B6, E, PP; contains calcium, potassium, sodium, magnesium, phosphorus, iron.

Useful tips from our teacher

Before you start cutting onions, you should dip the knife in cold water, to essential oils contained in onions did not irritate the eyes. And in order not to cry, peeling the onion from the husk, you should first hold it in cold water.

Onions are best preserved if hung in wreaths or in a net in a dry, ventilated place.

To remove bitterness in chopped onions, it must be scalded with boiling water, and then held in cold water for a while.

To prevent the onion from burning, before frying, roll it in flour or sprinkle with sugar.

If half of the onion remains, it should be lubricated with fat, then it will be well preserved.

4. Using a bow

Bow in folk medicine.

As a remedy in folk medicine in many countries, onions have been used since time immemorial. In ancient Rus', onions, as in Ancient Rome, was considered a universal remedy for all diseases. Wise folk sayings and proverbs about this vegetable have come down to our time:

"Onion - from seven ailments" (diseases).

"Onions and baths rule everything" (treat).

"He who eats onions is freed from torment."

Ш With fresh juice, warts, freckles, birthmarks, acne are removed, sores on the oral mucosa are lubricated, cotton swabs moistened with juice are placed in the ears with purulent otitis media.

Ш Compress from the onion, boiled in table vinegar, remove corns. For headaches, it is recommended to apply cut bulbs to the temples and forehead.

Sh Fried on butter onions are taken orally for coughs and chest pains.

Onion in cosmetology. Onion peel is also used for cosmetic purposes:

Ш Rinse the hair with a decoction, which will give the hair a golden-straw shade, strengthen their roots, and prevent the formation of dandruff. This recipe was used by the Egyptians more than four thousand years ago.

Ш It is useful to rub onion juice with a decoction of burdock roots into the scalp under the hair if you have dandruff.

Ш Onion masks refresh and nourish the skin.

Ш The water in which the onions were boiled is an excellent antibacterial agent. It's worth washing.

We are so accustomed to onions that sometimes we forget that at any time of the year we have at hand a cheap means of combating many diseases.

5. Bulb plants

When planting tulips and daffodils in the spring, we noticed that they also have a bulb. Onions belong to the bulbous family.

Plants with a bulbous organ are called bulbous plants.

In spring, the flower bud and leaf buds develop into a flowering plant, using the supply of water and nutrients accumulated in the fleshy leaves of the bulb. When the flower dies, the leaves continue to live and produce nutrients that are carried to the base of the leaves. They swell and turn into new bulbs, give rise to new plants.

The genus of bulbous plants is quite large. Today it includes 600 species of perennial herbaceous plants.

Interestingly, our most popular onion has not been found in its wild form.

Why do they say "onion woe"

When a person cries, it means that something happened to him. That's just the reason why tears well up in the eyes, not in all cases is associated with some kind of misfortune. When you peel or cut an onion, tears flow in a stream. And the reason for that is grief onion". This phraseological unit is also known in other countries, only there it is slightly modified. The Germans, for example, have the phrase "onion tears". These tears people shed over trifles. The expression "onion woe" also means minor troubles, much sadness because of which it is not worth it.

So, we learned a lot about the onion and bulb, as well as its family. Now it is necessary to confirm the hypothesis in a practical way.

6. Organization of observations

Target: finding out under what conditions the onion bulb will germinate and sprout.

We prepared buckets of soil and planted 3 bulbs, creating for them different conditions(in the dark, in the shade and in the light).

We have presented the results of observations in the table:

	conditions	result and conclusion.
Bulb №1 (In the dark)	Soil-ground, moderate watering, t + 18, no light	The bulb sprouted the very first, but the feathers are yellow, because the process of photosynthesis, which occurs in the light, is disrupted. Thus, the bulb used up its supply of nutrients. There is no taste of onion.
Bulb №2	light enters partially.	The bulb germinated a little later, the feathers are light green, long, directed in different sides, since there was not enough light, the process of photosynthesis took place partially. The feathers have a faint onion flavor.
Bulb №3 (in the light)	Soil-land, moderate watering, t + 20, on the windowsill, lots of light.	The bulb sprouted later than the others, the sprout is small, but the feathers are dark green, straight, with a pleasant onion taste. This bulb received a lot of light

Thus, our observations of the bulbs confirmed the hypothesis: if the bulb contains a supply of nutrients, then under certain conditions it will germinate and sprout in the form of a green feather. Light, water and heat are necessary conditions for plant growth. Lack of light leads to unhealthy growth, color changes. The plant tries to catch the light, so the feathers are directed in different directions. The bulb that was in the light had straight feathers.

But, if it were not for the supply of nutrients in the bulb, which it accumulated after flowering, then we could not have healthy green onions in the spring. Indeed, an onion bulb is a real pantry.

Useful advice from grandmother Nikita Mironyuk Proskurina L.V. - an experienced gardener:

1. For sowing, select small bulbs.

2. Use earth, peat, sawdust as soil.

3. Before planting, soak the bulbs in warm water for 10 hours. This is necessary so that the bulb wakes up.

4. Cut off the top - this will slow down growth, but increase yields.

6. Water abundantly at the beginning, but not often.

7. It is better not to pluck the onion feathers, but to remove the entire bulb as a whole.

Here is such a green vitamin bed on the windowsill that will delight you all winter!

Conclusion

Onions are an amazing vegetable. We eat both green “feathers” and the bulbs themselves. Onions - a source of vitamins and a means of combating diseases The onion bulb is a source of nutrients.

As a result of the work on the project “Why the onion needs an onion”, the goal was achieved, the tasks were solved, the hypothesis was confirmed.

We have made many discoveries for ourselves:

Ш got acquainted with the history of the bow;

W learned about the family of bulbous plants;

Ø gained practical experience in bulb germination;

Sh independently grew a small crop;

Sh saved the family budget, because green onions in the store are not cheap;

SH learned how to collect the necessary information and arrange it.

Literature

1. "Children's Encyclopedia of Cyril and Methodius, 2007"

2. Encyclopedia for children. Biology, publishing house "Avanta +", 1995, p.246

3. I.A. Vinshu "The Land of Our Care" - Serov, State Unitary Enterprise "PO Sever", p. 102

4. Jane Walker "Seeds, Bulbs and Spores", M., Flamingo Publishing House, p. 18

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Characteristic

Onions are a biennial crop belonging to the class of monocotyledonous plants. The homeland of onions is Afghanistan, Iraq and Turkmenistan, with a mountain climate characteristic of these regions (low air pressure and humidity, hard rocks and soil rich in minerals, but devoid of organic matter). Later, breeders bred many varieties adapted to different climatic conditions.

For the onion family, there is no clear distinction between organs. These plants are not divided into root, shoot, leaves. The reason for this is the gradual transition from one morphological part to another. The rhizome, transformed into a bulb, gives rise to a shoot that does not have a main stem, but is represented by a bunch of hard, erect leaves. Grow onions to obtain:

Sevka - in order to obtain further planting material. Usually, .
Directly onions, the varieties of which are described in.
For decorative purposes. Varieties and methods of growing ornamental onions are described.

Generative organs capable of sexual reproduction mature only in the second year of growth.

The root system of different types of onions

Like the entire class of monocots, onions have a fibrous root system. That is, the plant does not have a main root, but instead a lot of adventitious thin filaments-roots. This allows the onion to firmly establish itself in the soil: the roots gradually draw the bulb deeper, penetrate the soil with a dense network, and cling to the rhizomes of other plants.

Onions have a fibrous root system

Onions are still considered a superficial, shallow, sedentary crop. For this reason, it requires special loose soil types, especially when propagated by seeds.

Onion roots have a high capacity for chemotropism - the instinctive search for and absorption of dissolved nutrients. Roots are an annual structure and die off after the end of the growing season. Nutrients accumulate in a modified basal shoot - a bulb.

stem structure

The stem of the onion is also modified. It is presented in the form of a simplified plate - the bottom. On this plate is one or more buds, surrounded by leaves of the vaginal type. These kidneys are called buds.

When propagated by a vegetative method, a "heel" is formed in the plant - dead and hardened remnants of the maternal bottom. The heel protects the bulb from excessive moisture penetration and subsequent decay, which is especially important on final stages its development. Therefore, to ensure good keeping quality of the crop, it is more profitable to breed its sets.

Onion cut

The ability of the plant to produce a green crop depends on the number of primordia (the fewer primordia, the more actively the leaves develop).

leaf structure

Onions are characterized by conical, erect, cone-shaped leaves, narrowing towards the end and hollow inside. From frost and lack of moisture, the sheet is protected by a loose wax coating. The color of the leaves depends on the level of light: the more sunlight the plant receives, the lighter the color of the feathers. In general, the color varies from light green to gray-green, dark.

Leaves also vary in size and density. Toward the end of the growing season, the leaves become denser, acquire a pronounced venation (in onions it is longitudinal-transverse). The most dense are the leaves formed from the extreme open scales of the bulb. The multi-tiered onion has a different root system, which can be found.

Onion leaves are cone-shaped, tapering towards the end and hollow inside.

The structure of the bulb

The bulb is called false leaves sitting right on the bottom, protecting the kidney inside. The cross section shows that the scales form concentric circles, and their density and juiciness increase as they approach the center. Bulb-forming scales are divided into:

closed juicy. Modified leaves of a conical shape, not assimilating and performing an exclusively storage function.
open juicy. Thickened, non-photosynthetic parts of the leaf with a succulent base, thinning towards the top.
dry integumentary scales. They have a different color (depending on the variety -,), dense and smooth, protect the bulb from pests, drying out and help it to be stored for a longer time.

The juicy parts of the bulb, depending on the variety, may have a loose granular, fibrous, papery, mesh or membranous structure.

In the center of the bulb, buds are spirally located, from which heterophytes (flowering shoots) or new bulbs are formed in the future . By the number of such primordial buds, the onion primordia and nesting are determined.

The shape of the bulbs are divided into several main types:

flat;
rounded flat;
rounded;
long (elongated or oblong);
melon;
round melon.

The structure of the flower and shoot

The number and size of flowering shoots in onions depend on the variety and growing conditions. . They are formed after new feathers stop growing, at the very end of the growing season. For this reason, the shoot has the ability to photosynthesis, which ensures the maturation of seeds. Seeds are also involved in planting. As a rule, sevok is obtained from them. Growing onions in open ground with seeds and sets is described.

The flower stalks of onion plants are called an arrow, and the process of their formation is called arrowing. The arrow is a hollow thin-walled tube with a slight thickening at the base. Its length can reach from 45 to 130 cm.

Onion flowers can be white, blue, purple or yellowish in color. They form a complex inflorescence-umbrella, which can contain from several pieces to several thousand flowers. On average, the flowering period of an individual flower is 3-7 days, and the entire umbrella is 7-35 days. Symmetrical flowers do not have sepals, but they have a constant set of gametophytes - 6 stamens and 1 pistil.

reproduction

Onions are characterized by both sexual reproduction with the help of seeds and vegetative reproduction with the help of bulbs. Sexual reproduction occurs by self-pollination or pollination by insects. During double fertilization, one seed is formed for each flower. From the receptacle develops a dry multi-seeded fruit - a box. Seeds of irregular pyramidal shape ripen within 40-60 days. After the seeds, covered with a dense black peel (for which the people called them "chernushka"), are ready for assembly . In 1 gram, up to 1000 individual grains usually fit.

Under unfavorable conditions, vital processes freeze, the active formation of primordia and the accumulation of nutrients in the bulb begin.

In this form, the plant is going through a difficult period, and with the onset of heat it gives several arrows at once and does not form bulbs at the second stage of development.

Landing Features

Given this structure of the plant, it can be assumed how and where onions should be planted. The most profitable is the breeding of sets, while the onions are buried shallowly in loose, abundantly watered soil. . Early-maturing varieties can be sown with nigella, grooves up to 1 cm deep. It should be planted in a well-lit place, avoid darkening and excess moisture.

Landing occurs at the end of April, when the soil is well warmed up and the longest daylight hours.

Video

conclusions

The structure of onions allows it to easily survive an unfavorable period, but this will significantly reduce its yield. Maintaining normal conditions is the key to abundant fruiting, good keeping quality of the bulbs. Knowing the stages of onion development, it is possible to establish a regime for cultivating it as a two-year crop, which will significantly increase its productivity. How to store onions at home is described in this.

Onion plants are not as clearly divided into roots, stems and leaves, as we are used to seeing in other garden and garden crops. The leaves of onions are tubular or tubular, hollow inside or flat (Fig. 1), of various shapes and sizes. For example, onion leaves are fistulate, garlic has a flat linear one, tapering towards the end without a cavity; in wild garlic - also flat, but wide lanceolate. The cotyledon and the first true leaves of all types of onions are fistulate. The lower parts of the leaves are tubular sheaths, from which false stems are formed, and when thickened, bulbs.

The color of the leaves is from light to dark green, even gray. Usually onion leaves are covered with a wax coating of varying intensity, but it may be absent. The wax coating performs a protective function, protecting the leaves from damage by phytopathogens and damage by virus vectors. The number of leaves varies from one or two to forty or more. The onion stalk is greatly shortened and is called the bottom (Fig. 2). One or more buds (rudiments) develop on the bottom, which are surrounded by leaf sheaths. In vegetatively propagated (propagated using plant parts, not seeds) plants, the lower part of the bottom - the remainder of the bottom of the mother bulb - is called the heel. The dead tissues of the heel are very dense and hard and prevent moisture from reaching the bottom, protecting the bulb from premature regrowth of roots. Bulbs grown from seeds do not have heels. A certain number of buds, or rudiments, are formed on the bottom, which is called rudimentary, and the ability to form one or another number of bulbs on one bottom from rudiments is nesting.

Fig 2. The structure of the bulb (on the left - a longitudinal section, on the right - a transverse one): 1 - dry integumentary scales; 2 - open juicy scales; 3 - closed juicy scales; 4 - rudiments; 5 - bottom; b - heel; 7 - neck Varieties of onions can be single-bearing (respectively, single-nested), medium and multi-bearing. The budding and nesting depending on it are determined by the degree of onion branching and serve as varietal characteristics. Short lateral shoots - the buds are located on the bottom stem in a spiral. They are called branches. The buds on the bottom are formed non-simultaneously - their formation occurs gradually during the growing season and during storage. In the future, new bulbs or flower stalks with inflorescences develop from the kidneys.

With the development of leaves from their sheaths, a false stem is formed. It is supported in an upright position by young leaves growing in the center from the inside (Fig. 3). As it grows, the bases of the leaves thicken, fleshy scales form, from which the bulb is formed. Gradually, the leaves die off, starting from the very first time of appearance, the false stem dries up, forming the neck of the bulb. The earlier the neck dries up, the thinner it is and the sooner the bulb ripens. The bulb consists of a bottom with modified leaves-scales sitting on it and a bud inside. Outside, the onion bulb is covered with dry scales of various colors (see Fig. 2). The outer shells of the bulb, which protect it from adverse external influences, in onions of different types can be thick or thin, leathery, membranous, papery, fibrous, mesh, etc.

Rice. 3. Scheme of the formation of leaves in onions: I - leaf blade; 2 - leaf sheaths; 3 - false stem; 4 - shoot growth point; 5 - germinal root; b - adventitious roots Their color is also very diverse - white, gray, yellow, brown, dark red, purple in different shades. Juicy scales are of two types: external open and internal - cone-shaped closed. This is clearly seen if you cut the onion bulb in the center along. Open scales are thickened parts of green leaves in which reserve nutrients are deposited. With the onset of thickening of open juicy scales, leaves of a different type appear inside the onion - closed scales. These are non-assimilating modified leaves that serve to store nutrients.

The ratio of closed and open scales - important indicator keeping quality of the bulbs. The more closed scales, the better and longer the onion is stored. With the formation of closed scales, the growth of new leaves stops, the false stem remains hollow inside, and the onion lies down under the weight of the leaves. Lodging is an important sign showing the beginning of bulb maturation. Due to the drying of several outer juicy scales, dry cover scales of a certain color for a given variety are formed. Types of onions are characterized by a wide variety of bulbs. They can be real, like the onion bulb described above, or false, not having closed scales. The most interesting is the prefabricated bulb of garlic, consisting of onion-teeth. For many species, for example, onions, batun, chives and others, the formation of only false bulbs that do not ripen and cannot be stored is typical. Outwardly, false bulbs differ from real bulbs in a smaller thickening of the leaf sheaths, the absence of a pronounced neck - the transition from the false stem to the bulb itself is not sharp, smooth. The shape of such bulbs is elongated (Fig. 4). The mass of the bulbs can be different - from 1 g or less to 1 kg, depending on the species, variety, place and growing conditions. In many species, small baby bulbs are formed on the bottom, as well as bulbs on stolons. In garlic, multi-tiered onions, blue onions and other onions, small bulbs, called bulbs, are formed in inflorescences along with flowers or instead of flowers. The development of bulbs in the inflorescence is called viviparia (from the Latin word vivus - live, in pairs - to give birth), or live birth. Bulbs are colored, often unevenly, green or purple. Fig 4. Scheme of the structure of the onion-batun: 1 - leaves; 2 - longitudinal section of a false bulb; 3 - rhizome; 4 - roots; 5 - sighting bulb; b - peduncle Air bulbs are used for vegetative propagation, as a rule, their formation is associated with a decrease in the ability of plants to form normally developed seeds. Most perennial onion species have a rhizome. A rhizome is a modified stem located in the soil and along appearance(brown color, lack of green leaves) similar to the root. On the rhizome, you can see modified leaves - scales that are short-lived and quickly fall off. The rhizome has internodes in which buds are formed, subsequently giving rise to new shoots.

Rhizomes come with short internodes and crowded buds, which leads to a close arrangement of shoots, or with long internodes, like wheatgrass. The latter reproduce better, since the shoots formed in the nodes spread faster over the site. Rhizome plays important role during vegetative propagation of onions. When the old parts of the rhizome die off, the shoots of the plant stand apart and become independent plants. The rhizome of onions serves as a reservoir of reserve nutrients. False bulbs are attached to it. The bottoms of the latter either directly continue the rhizome, or are delimited from it. However, young shoots always use the nutrients of bulbs and rhizomes that store scales for development.

Onions are considered plants with a weak root system, which determines their increased demands on soil conditions, especially in the early stages of development from seeds. At the same time, some species, such as the Pskem onion, which grows in nature in rock crevices and on mountain screes, have very strong, powerfully developed roots that allow them to exist in such harsh conditions.

Species such as onions, in which real bulbs are formed, have a fibrous root system that does not penetrate deep into the soil and is slightly branching. The roots of these species are annuals, they die off simultaneously with the end of the vegetation of the aerial organs. In species with a well-developed rhizome, with a long growing season, for example, in the slug onion, roots are formed both on the bulbs and on the rhizomes. However, the nature of these roots is different. Bulb roots spread horizontally and branch heavily to form third-order roots. They are annuals, that is, they die off at the end of the growing season. The roots extending from the rhizome are perennial, spread vertically in the soil, branching not very strongly - until the formation of second-order roots. The penetration depth of the latter is 60 ... 80 cm. There is also information about a deeper penetration of the roots of onions (up to 120 cm), perennial onions (up to 150 cm), but these are only single roots. The flower-bearing onion shoot is called a peduncle or flower arrow . The peduncle develops when the formation of the leaves is completed and they begin to die. The arrow emerges from the false stem in the axil of the last leaf (Fig. 5). Bows have a green flower arrow. Due to its photosynthetic activity, the formation and filling of seeds is ensured. The size, shape of flower stalks and their number differ in species and varieties of onions. Cross sections of flower arrows of different types were shown in Figure 1. In onions, the bases of flower arrows are narrow, then widened.

Figure 5. A flowering plant of the Altai onion burrows, forming a swelling, and narrows again towards the inflorescence. The swelling on the flower arrows has an adaptive value. It helps to increase the resistance of flower stalks to lodging. The timing of planting has a great influence on the number of primordia, and, consequently, flower arrows. The onion inflorescence is a simple multi-flowered umbrella, the shape and number of flowers in which depend on the type of plant. There may be several pieces of flowers, and maybe up to a thousand or more. Usually onion flowers are small - 0.3 ... 1 cm in diameter, in some species they are large - up to 3 cm, but at the same time they bear little resemblance to the flowers of other onions.

The young inflorescence is at first covered with a membranous wrapper of several fused leaves. The wrapping is called a cover, or a coverlet. Its shape and size serve as specific and varietal characteristics. With the growth of buds, the growth of the inflorescence, the cover breaks and dries up, freeing the inflorescence before the flowers begin to bloom. The diameter of the inflorescence is from 5 to 15 cm. The rudiments of flowers on the common receptacle of the inflorescence are laid and do not form simultaneously. This causes the flowers to bloom at different times in the inflorescence.

The duration of flowering of individual flowers in the southern regions is one or two days, in the middle lane - five to seven. In total, the onion inflorescence blooms from 15 to 35 days. The whole plant blooms even longer, since the inflorescences are laid and also develop at different times. In onions, the flowers of the first tier usually bloom first (at the top of the inflorescence), the buds of the second tier at this time have short pedicels and are located under the flowers of the first tier, and small buds of the third tier are located at the base of the inflorescence. Part of the buds of the third tier, as a rule, dries up without opening. As the flowers of the previous tier fade, the pedicels of the buds of the next tier lengthen and bring the blossoming buds up. By the end of flowering, the longest are the pedicels of the late-blooming flowers of the third tier. Onion flowers have a regular symmetrical shape, without a calyx. There are six petals in the corolla of a very diverse color - white, yellow, greenish, pinkish, blue, purple in different shades, etc. Often there is a dark central vein on the petals. Stamens six, pistil one (Fig. 6). The anthers of the stamens, as well as the petals of the corolla, have a different color, and the pedicels also have a different color. Nectaries are located at the base of the onion ovary. The flowers of some species, such as fragrant onions, have a pleasant aroma, completely different from the usual pungent odor for onions. The onion fruit is a dry three-celled box in which up to six seeds can form, but two or four are more often tied. The seeds are black (they are sometimes called nigella), irregularly triangular in shape, covered with a hard wrinkled cornea, which protects well from adverse effects. Rice b. Onion flower and fruit: a - flower during flowering; b - seed box when pouring seeds; c - an opened box with a seed The size, shape and weight of seeds are characteristic of the species, although significant variability is observed. Small-seeded species include chives, in 1 g it contains from 800 to 1000 seeds, in onion seeds are much larger - only 250 ... 400 pieces per 1 g. The seeds of ephemeroid onions are even larger - about 200 seeds in 1 g. The shape is flat-convex, concave-convex, trihedral, spherical. The biological characteristics of onion seeds also depend on the conditions in which the species historically formed in nature. Conventionally, they can be divided into three groups: first, the seeds of species that have formed under conditions of sufficient moisture, favorable for the development of onions; this includes onions and onions; these seeds do not have a dormant period and can germinate at temperatures from 4 to 30 °C. They can be sown at any time - in spring, summer, before winter; secondly, seeds of species that have formed in zones of a sharply continental arid climate, including onions from Central Asia and all ephemeroid species; the seeds of such onions are distinguished by a large mass, have a dormant period, germinate well at a temperature of 4 to 10 ° C; they should be sown only before winter; thirdly, seeds with an extended germination period; types of onions with such seeds grow in harsh conditions; their most important property is the non-simultaneity of germination, which serves as an adaptation for survival; wild garlic has these seeds; if seedlings of one germination period die due to unfavorable conditions, the species survives at the expense of seedlings of other periods; the seeds of this group are also sown before winter.

In most cases, it takes 40 to 60 days for the full formation of seeds. Seed development begins after pollen hits the stigma of the pistil style. In the development of seeds, they distinguish: the phase of milky ripeness - the age of the seeds is 20 ... 25 days; at this time they are immature, unsimilar, still soft and, when pressed, a white liquid similar to milk flows out of them; ripening during the removal of fruits in this phase is impossible; the phase of wax ripeness - the age of the seeds is 30 ... 35 days; the seeds are almost formed, become hard, when pressed, they are only slightly deformed; some are already able to germinate; seeds harvested in wax ripeness ripen well; the phase of complete biological ripeness of seeds; occurs in onions, depending on the variety and place of cultivation, on the 50th ... 60th day after fertilization; characterized by cracking of the bolls and spillage of seeds, the latter at this time are well made, firm, germinating by 95 ... 98%. The viability of the seeds depends on their moisture content and storage conditions. When stored in constantly changing conditions, the seeds quickly, in two or three years, lose their germination capacity.

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Onion - useful properties and growing conditions

Bulb onions

The use of onions in nutrition

Onions are incredibly important in our diet, but at the same time, they are often invisible in dishes. In fresh vegetable salads, of course, you can immediately see it, but in the first and second courses it seems to be hiding, and you fully realize how much it is needed for their general taste only when it is suddenly not there. At the same time, it is easier to list those dishes for which it is not needed than those in which they put it. And although, if measured only by weight, we eat a little onion, this is the only vegetable that we need every day for health.

Useful properties of onions

Onion is one of the most ancient vegetables, known for at least 6000 years, but, most importantly, it is one of the most useful. Even those who do not like onions still rarely refuse it completely, because as a prophylactic against many diseases, only garlic can compete with it. But there are no medicines. And it protects against almost the most common diseases, such as colds and flu. In the fall, those who do not want to sit on sick leave or just squish their noses cannot do without it. But the healing properties of onions are not limited to getting rid of colds: the phytoncides that it contains destroy the pathogens of even such dangerous diseases as tuberculosis, diphtheria, or typhus and cholera, which have almost disappeared today, but mowed down entire cities in the past. It also contains vitamins, and also in considerable quantities. And it is no coincidence that our ancestors said about the onion that it is “from seven ailments”. And now medicines are made from it. And one more very useful property there is onion: those who eat a lot of it fresh, wrinkles do not appear much longer. Agree, for the sake of this, you can endure the smell of it, especially if you eat it at home, after work. On the other hand, onions can be used as a natural substitute for pesticides in the same garden - an infusion of it repels many pests, not to mention the microbes that die from it.

bow structure

The most common of the cultivated bunches was called onion because its bulb looks like a turnip. At its core, it is something like a cabbage head, because it is formed by parts of leaves, with the difference that onions have changed much more and not all of them - part has turned into scales, and the rest are feathers sticking out above the bulb. The uppermost scales of the onion dry out and serve as additional protection for the rest (Fig.). The roots of the onion are fibrous, they do not climb too deep. The bottom of the bulb is actually a stem, only very unlike itself, but it is on it that the buds are laid and develop, from which new leaves are formed (more precisely, their nests, of which there may be several), and when the time comes, also peduncle - an arrow with an inflorescence-ball on top. If you look closely at its small flowers, you will notice that in shape each one looks like a tiny tulip or lily. And this is also not accidental - the onion is a member of the lily family and is closely related to the lily.

Rice. Onion in the context: 1 - juicy scales; 2 - dry scales; 3 - pen; 4 - bottom; 5 - roots

But the onion itself has three subspecies, outwardly similar, but with slightly different requirements for conditions and care - these are the northern (sharp) onion, the southern (sweet) onion and white onion.

Northern onion is the most unpretentious and cold-resistant. Its seeds germinate at +5°C, and seedlings tolerate light frosts well. His bulbs are usually not too large, often multi-celled and the most stale, and the taste is the most “evil”.

The southern onion is thermophilic, in cold regions it not only grows poorly, but also loses its varietal qualities, first of all, the sweetness for which it is valued. Freezing can kill it. The bulbs of the southern sweet and semi-sweet (semi-sharp) onions are usually large, but poorly stored, so they are used mainly for salad.

White onions have appeared recently. In terms of love for warmth, it is average between spicy and southern, in taste it is closer to southern, and its main value is that after its use there is no smell from the mouth. When moving to the north, its taste almost does not deteriorate, but white onions do not tolerate frosts well, and therefore even in central Russia they have to protect them.

Read more about the variety of varieties of onions in the article "The best varieties of onions".

In this case, all three subspecies can use a pen.

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Botanical characteristics of onions

Onion (Allium cepa) is a biennial plant with a weak root system and a well-defined bulb. Onion plants are not as clearly divided into roots, stems and leaves, as is observed in other garden crops. The lower parts of the leaves are tubular sheaths, from which false stems are formed, and with a thickening of the bulb.

root system. Onions are considered plants with a weak root system, which determines their increased demands on soil conditions, especially in the early stages of development from seeds. Species such as onions, in which real bulbs are formed, have a fibrous root system that does not penetrate deep into the soil and is slightly branching. The roots of these species are annual, they die off simultaneously with the end of the vegetation of the above-ground organs.

The structure of the stem. The stalk of the onion is greatly shortened and is called the bottom. One or more buds (rudiments) develop on the bottom, which are surrounded by leaf sheaths. In vegetatively propagated (propagated using plant parts, not seeds) plants, the lower part of the bottom - the remainder of the bottom of the mother bulb - is called the heel. The dead tissues of the heel are very dense and hard and prevent moisture from reaching the bottom, protecting the bulb from premature regrowth of roots. Bulbs grown from seeds do not have heels. A certain number of buds, or primordia, is formed on the bottom, which is called primordia, and the ability to form a different number of bulbs on one bottom from primordia is nesting.

The structure of the leaves. The leaves of onions are tubular or ventilated, hollow inside or flat, of various shapes and sizes. For example, onion leaves are fistulate, garlic has a flat linear one, tapering to the end without a cavity, wild garlic is also flat, but lanceolate and wide. The cotyledon and the first true leaves of all types of onions are fistulate.

Cross section leaf (top) and peduncle (bottom) of different types of onions.

The color of the leaves varies from light green to dark green, even gray. Usually onion leaves are covered with a wax coating of varying intensity, but it may be absent. The wax coating performs a protective function, protecting the leaves from damage by phytopathogens and damage by virus vectors. The number of leaves varies from one or two to forty or more.

Bulb structure. The bulb consists of a bottom with modified leaves sitting on it - scales and a kidney inside. Outside, the onion bulb is covered with dry scales of various colors. The outer shells of the bulb, protecting it from adverse external influences, in various kinds bows can be thick, thin, leathery, membranous, papery, fibrous, mesh and others.

Their coloration is also very diverse - white, gray, yellow, brown, dark red, purple in different shades. Juicy scales are of two types: external open and internal - cone-shaped closed. This is clearly seen if you cut the onion bulb in the center along. Open scales are thickened parts of green leaves in which reserve nutrients are deposited. With the onset of thickening of open juicy scales, leaves of a different type appear inside the onion - closed scales. These are non-assimilating modified leaves that serve to store nutrients. The ratio of closed and open scales is an important indicator of bulb keeping quality. The more closed scales, the better and longer the onion is stored. With the formation of closed scales, the growth of new leaves stops, the false stem remains hollow inside, and the onion lies down under the weight of the leaves.

The structure of the bulb (left - longitudinal section, right - transverse):

1 - dry integumentary scales; 2 - open juicy scales; 3 - closed juicy scales; 4 - rudiments; 5 - bottom; b - heel; 7 - neck.

Varieties of onions can be single-bearing (respectively, one-celled), medium-bearing and multi-bearing. Short lateral shoots - the buds are located on the bottom stem in a spiral. They are called branches. Buds on the bottom are not formed simultaneously - their formation occurs gradually during the growing season and during storage. In the future, new bulbs and flower stalks with inflorescences develop from the buds.

According to the number of primordia, varieties are distinguished as one, two or few-primordial and multi-primary. Each primordium develops leaves, and then a flower-bearing arrow. Small-sized varieties usually form large bulbs with thick, juicy scales of a slightly spicy taste. These include mainly southern lettuce varieties. Sharp varieties most often have multi-primary bulbs with thin, juicy scales tightly adjacent to one another.

Longitudinal section of onion bulbs differing in the number of primordia:

1 - single germ; 2 - bisexual; 3 - multigerm; 4 - arrow bulb: a - arrow, b - sighting bulb.

Bulbs can be of various sizes - from 5 ... 20 grams to 800 grams, as well as various shapes.

Bulb shapes of various varieties of onions: flat, round-flat, round, melon, elongated-melon and long.

The structure of the flowering shoot. The flower-bearing shoot of the onion is called the peduncle or flower arrow. The peduncle develops when the formation of the leaves is completed and they begin to die off. The arrow emerges from the false stem in the axil of the last leaf. Bows have a green flower arrow. Due to its photosynthetic activity, the formation and filling of seeds is ensured.

Flower arrows develop from primordia. Therefore, by the number of primordia, it is possible to determine the number of flower arrows in a seed bulb. Arrows are hollow, tender, of various heights (50…175 cm) depending on the variety (mainly on the size of the bulb) and growing conditions. The size, shape of flower stalks and their number in species and varieties of onions differ. In onions, the bases of the flower arrows are narrow, then expand, forming a swelling, and narrow again at the end.

The inflorescence of onions is a simple multi-flowered umbrella, the shape and number of flowers in which depend on the type of plant. There may be several pieces of flowers, and maybe up to a thousand or more. The duration of flowering of individual flowers in the southern regions is 1 ... 2 days, in the middle lane - 5 ... 7 days. In total, the onion inflorescence blooms from 15 to 35 days.

The structure of flowers. Onion flowers have a regular symmetrical shape, without a calyx. There are six petals in the corolla of a very diverse color - white, yellow, greenish, pinkish, blue, purple. Often the petals have a dark central vein. Stamens six, pistil one. The anthers of the stamens, as well as the petals of the corolla, have a different color, and the pedicels also have a different color. Nectaries are located at the base of the onion ovary. The flowers of some species, such as the fragrant onion, have a pleasant aroma, completely different from the usual pungent smell for onions.

The structure of the fetus. The fruit of the onion is a dry three-celled box in which up to six seeds can form, but two to four are more often tied. Seeds are black (they are sometimes called nigella), irregularly triangular in shape, covered with a hard horn-shaped shell, which protects the seeds well from adverse effects.

Onion flower and fruit:

a - a flower during flowering; b - seed box when pouring seeds; c - an opened box with a seed.

The size and weight of the seeds are characteristic of the species. Small-seeded species include chives, in 1 gram it contains from 800 to 1000 seeds, in onion seeds are much larger - in 1 gram there are only 250 ... 400 pieces. Most seeds take 40 to 60 days to fully form. Development begins after pollen hits the pistil column.

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The structure of the bulb, rhizome, tuber

The bulb is an underground shoot with leaves closely attached to the bottom. The structure of the bulb in different plants is the same, but may differ in shape and size. In their structure, all bulbs are similar to the usual onions.

General structure

Considering the structure of the bulb in the section, it is clear that there is a bottom at the very bottom. Below it are the roots, and above - modified shoots. They accumulate nutrients for a dormant period.

Modified shoots include not only bulbs, but also rhizomes and tubers. Plants with rhizomes are irises, wheatgrass, nettles. There are few tuberous plants, one of the most famous is the potato. He has shoots underground, on upper parts which tubers grow. They have shortened internodes and do not contain chlorophyll. However, when tubers are exposed and exposed to direct sunlight for a short time, the tubers may turn green.

Looking at the structure of the bulb, you can see the embryos of the leaves. They accumulate a large amount of nutrients. They allow the leaves to start growing at any time of the year. Therefore, it is bulbous plants that are used for early forcing, planting them in winter. This is their difference from other plants. Another difference is that the number of leaves is precisely determined in bulbous ones, that is, the number of primordia is equal to the number of leaves.

At the bottom of the bulbs, near the bottom, flower buds are located. How many buds are laid, so many flower shoots will grow.

When caring for bulbous plants, damaged and dried leaves should be carefully cut off, since if the primordia are damaged, the leaf dies, and if the entire bulb is severely damaged, the entire bulb may die.

In different plants, the scales of the bulb adjoin each other in different ways. In lilies, they are located loosely to each other, but there are plants with a snug fit, such as hyacinths.

bulb types

The internal, as well as the external structure of the bulb, is different for different types of plants. They are divided into the following subspecies:

Film. Scales can cover completely inner part. The scaly edges touch. There are plants in which the scales can grow together.
Semi-tunic. There are scales that never grow together.
Tiled. The scales are very narrow. On one edge, they are in contact with neighboring scales.
The number of scales in different plants is different. Some may have one, others three, five or more.

All scales are divided into:

leafy;
grassroots.

From below, the scales grow, and reserves of nutrients are made in them.

Tuber structure

The internal structure of the tuber and bulb is different. On the outer side of the tubers are sprouts - they are called eyes. There are more of them on the top than on the bottom. When planting in the ground, the aerial part grows from the eyes.

The tubers have stolons on the underside. They provide nutrients. They accumulate in the shoots, then there is an active growth and thickening of the shoots, and by autumn tubers grow on the stolons.

The structure of the bulb and tuber is similar only in that they accumulate substances useful to the plant. Otherwise, they are different.

The structure of the rhizome

The rhizome is also an underground shoot of a modified type, which develops in perennials, shrubs. In it, as in the bulb, the nutrients necessary for the plant for normal development and maintenance of life are stored.

The external structure of the rhizome of the bulb resembles an ordinary root, but differs in dissected internodes and scaly leaves on which axillary buds are formed. When the aerial part dies off, a scar remains on the rhizome.

There are simple, thin, horizontal, thick, branched, vertical and ascending rhizomes. These are not all variants of rhizomes.

The life span of the rhizome is five years on average. In some plants, it can live for two years, and in some - more than ten years.

Conclusion

Rhizome, tuber and bulb of plants are different types of modified shoots. They are similar in that they have short internodes, accumulate a large supply of trace elements and other nutrients. These plant organs do not contain chlorophyll.

Underground shoots are pantries of vital substances. They contain starch, mineral elements, phytoncides. These plant parts can be used as food by humans and also used as animal feed.

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Botanical features of onion | Nasha Gryadka.ru

Onions belong to the lily family. The genus of onions (allium) has about 400 species, more than half of which grows in our country, mainly in the mountainous regions of Alai, as well as in Central Asia. Of all this number of species, only seven are in culture: onion, shallot, batun, porrey, garlic, chives or chives, and the multi-tiered onion recently introduced into the culture.

Many of the wild-growing onions are used as food by the local population, and some are even harvested for future use, such as skoroda onions, which grow in abundance in the meadows of the Volga region and Siberia. Eleven types of wild-growing onions are used for food in Kazakhstan, among which there are also onion forms. Among the bows there are also beautifully flowering ornamental species that can take a place in our flower beds.

Onion is a perennial plant. The cycle of its development from seed to seed is two to three years. Onions hibernate in the form of a bulb.

The base of the bulb (bottom) is a real shortened and expanded plant stem. On the top of the bottom there is one or more points of growth - the primordia, which are clearly visible in the cross section of the bulb. The rudiments are surrounded by juicy scales of the bulb, which are the bases of the leaves with nutrients deposited in them. Outside, the bulb is dressed with dry scales, protecting it from drying out and damage. Usually there are from two to five, they are painted, depending on the variety, in white, yellow and red, in different shades. The denser the dry scales and the more of them, the more stable the onion is in storage. The lower part of the bottom is called the heel. It is the larger, the older the bulb. In an annual onion, the heel is small and covered with the remains of roots.

Onion roots are straight, string-shaped, poorly developed, have few root hairs and plunge vertically into the soil to a depth of no more than 60-80 centimeters. According to Professor Edelstein, the volume of soil used by onion roots is 20-25 times less than that of carrots or cabbages. Therefore, onions are very demanding on the content of nutrients in the soil and respond well to fertilizing and loosening the soil.

Onion leaves are tubular, hollow. Each new leaf grows inside the previous one in such a way that the bases of all leaves nested one inside the other form a false stem. This stem is supported in an upright position by a growing young leaf. When the growth of new leaves stops, the false stem falls down, and the nutrients from the leaves pass into the bulb.

The size of the bulb depends on the number and size of the leaves: the more powerful the leaves and the more of them, the larger the bulb. Agrotechnics for growing onions should be built in such a way as to ensure best conditions at first for rapid growth, and in the second half of summer for the rapid ripening of the bulb. The better the bulb ripened and went into a dormant state earlier, the better it is stored in winter. Depending on the conditions of winter storage, onions planted in the ground in spring either give an arrow or form a nest of daughter bulbs.

To proceed to flowering, the bulb must go through the vernalization stage, which takes place at a temperature of 2 to 15 degrees throughout the entire period of ripening and storage of the bulb. A vernalized bow after planting in the ground gives from one to five arrows. The flower arrow carries 200-800 flowers per inflorescence - an umbrella. The inflorescence is covered with a membranous wrapper, falling off before flowering. The flowers are quite small, greenish-white, with a net of petals and six stamens. Ovary free, three-celled.

The ripened fruit is a trihedral capsule containing a maximum of six seeds. Seeds are black, trihedral, with a wrinkled cornea. For their black color, onion seeds are called "chernushka". Due to the dense shell, onion seeds swell poorly and, if there is not enough moisture in the soil, they germinate very slowly.

A single cotyledon of onion appears on the surface of the soil in the form of a loop. Continuing to grow, the loop pulls the upper end out of the soil with the remnants of the seed coat. After three to five days, the first true leaf sprouts at the base of the loop. The next two or three onion leaves are still very small and grow slowly. Only 25-30 days after germination, starting from the fourth or fifth leaf, their size increases and growth is coming faster.

If the onion at the stage of three or four leaves does not have enough moisture and nutrition, then a small bulb is formed, consisting of one or two juicy scales. Such a bow, from 1.5 to 2 centimeters in diameter, is called a set. It is obtained with heavily thickened sowing as planting material for growing large turnips.

Conversely, by continuously supplying the onion plant with moisture and nutrients, you can make it grow until late autumn. The plant will develop a large number of powerful leaves, but the bulb will not go into a dormant state - it will not ripen. Knowing the needs of the plant in different periods of its development, it is possible to control its growth and obtain the products that are needed.

1 - wild garlic; 2 - onion; 3 - chives; 4 - garlic

Requirements of onion plants to environmental conditions

The main environmental conditions that determine the growth and development of a plant are light, heat, moisture and food. Onions are undemanding to the intensity of light, but still do not tolerate strong shading.

Northern onions are long day plants. At short day(less than 12 hours) the formation of the bulb is greatly delayed, and the leaves grow faster. In the Middle lane, in the Urals and the Volga region, where the length of the day in June-July is 16-18 hours, there are all conditions for the rapid formation of the bulb. Agricultural technology must provide fast growth plants before bulb formation begins.

Soil moisture is critical to onion development. For seed swelling, bulb germination, leaf formation, a large amount of moisture is needed. And watering the onion at the beginning of its growth, in May-June, is very favorable for the harvest. As soon as the bulb has formed (at the end of June, in July), excess moisture is harmful. It delays ripening and can cause the growth of onions, and such onions cannot be stored in the winter.

Onions are among the cold-resistant plants. Its seeds can germinate at a temperature of 1-2 degrees Celsius. Onion seedlings tolerate short-term frosts of 1-2 degrees, and adult plants up to 6-7 degrees of cold and below. Often in the spring you can see regrown bulbs that have lain in the soil all winter.

Onions are well stored in winter at a temperature of 1-3 degrees of cold and do not die if it is briefly lowered to 5 degrees. Due to the poorly developed root system, onions especially need rich, well-fertilized and loose soil, easily accessible food, especially since it forms a crop in a short period. But onions do not tolerate a high concentration of nutrient salts. Therefore, he gives much top scores, if the required amount of fertilizer is applied not immediately, but several times during the growing season in the form of dressings.

General structure

To include not only bulbs, but also rhizomes, tubers. Plants with rhizomes are irises, couch grass, nettles. There are few tuberous plants, one of the most famous is the potato. It has shoots underground, on the upper parts of which tubers grow. They have shortened internodes and do not contain chlorophyll. However, when the tubers are exposed and exposed to direct sunlight for a short time, the tubers may turn green.

Looking at the structure of the bulb, you can see the embryos of the leaves. They accumulate a large amount of nutrients. They allow the leaves to start growing at any time of the year. Therefore, it is used for early distillation, planting them in winter. This is their difference from other plants. Another difference is that the number of leaves is precisely determined in bulbous ones, that is, the number of primordia is equal to the number of leaves.

At the bottom of the bulbs, near the bottom, flower buds are located. How many buds are laid, so many flower shoots will grow.

In different plants, the scales of the bulb adjoin each other in different ways. In lilies, they are located loosely to each other, but there are plants with a snug fit, such as hyacinths.

bulb types

The internal, as well as the external structure of the bulb, is different for different types of plants. They are divided into the following subspecies:

Film. Scales can cover the entire interior. The scaly edges touch. There are plants in which the scales can grow together.
Semi-tunic. There are scales that never grow together.
Tiled. The scales are very narrow. On one edge, they are in contact with neighboring scales.
The number of scales in different plants is different. Some may have one, others three, five or more.

All scales are divided into:

leafy;
grassroots.

From below, the scales grow, and reserves of nutrients are made in them.

Tuber structure

The tubers have stolons on the underside. They provide nutrients. They accumulate in the shoots, then there is an active growth and thickening of the shoots, and by autumn tubers grow on the stolons.

The structure of the bulb and tuber is similar only in that they accumulate substances useful to the plant. Otherwise, they are different.

The structure of the rhizome

The rhizome is also an underground shoot of a modified type that develops in perennials and shrubs. In it, as in the bulb, the nutrients necessary for the plant for normal development and maintenance of life are stored.

The external structure of the rhizome of the bulb resembles an ordinary root, but differs in dissected internodes and scaly leaves, on which they form. When the aerial part dies off, a scar remains on the rhizome.

There are simple, thin, horizontal, thick, branched, vertical and ascending rhizomes. These are not all variants of rhizomes.

The life span of the rhizome is five years on average. In some plants, it can live for two years, and in some - more than ten years.

Conclusion

Underground shoots are pantries of vital substances. They contain starch, mineral elements, phytoncides. These plant parts can be used as food by humans and also used as animal feed.

The onion bulb (Allium cepa L.) consists of a shortened stem (bottom), which hosts one or more generative and vegetative buds. From generative buds, under appropriate conditions, a flower stem develops. (arrow) bearing flowers and seeds, from vegetative - a new bulb. kidneys (rudiments) surrounded by fleshy scales (modified leaves). The inner fleshy, juicy scales serve as a place where reserve nutrients are deposited. Some of them (open) continue up into green tubular leaves (feather onion), others (closed) remain in the bulb and serve to nourish the developing buds. The outer scales dry out and become dense, leathery, dry (Fig. 67). They bear the name shirts and serve to protect the bulb from drying out and mechanical damage. The property of an onion to form a different number of buds on the bottom is called rudimentary. Depending on the number of primordia, bulbs are single, double or multi-primary. If the process of branching of the bulb goes further, then several separate bulbs can form on one bottom, which is called nesting and distinguish between bows one-, two-, three- or multi-cavity (Fig. 68). Bows with many nests are usually more productive than those with small nests. In the lower part of the donut, the tissues gradually die off and become hard; this part is called heel.

The bulb of the described structure, which is characteristic not only for onions, but also for some other types of onions and for garlic, is called real bulb and, according to the definition of M. V. Alekseeva, is a dormant plant. Moreover, the more closed scales in the bulb and the fewer open ones, the deeper the period of its dormancy.

In the process of seed germination, a root, a hypocotyl knee and one cotyledon are formed, which initially remains in the seed. Therefore, the hypocotyl knee appears on the soil surface in the form of a "loop". Continuing to grow, the subcotyloid knee gradually removes the cotyledon with the seed coat from the soil and straightens. With a very deep placement of seeds in dense soil, not a cotyledon, but a root can pull out to the surface, and the plant dies. In the loop phase, a bud is formed inside the hollow cotyledon leaf, from which the first true leaf develops; it exits through a small hole in the cotyledon leaf. All subsequent leaves appear but in turn, sprouting from the inside of the previous one. As a result, a false stem, consisting of nested tubular sheaths of leaves.
In some varieties of onions, small onions can form on the stem, in inflorescences. They have the same structure as the underground ones, and are called air bulbs or bulbs.
root system onion of a fibrous type, is relatively poorly developed and is located mainly in the uppermost (30-50 cm) soil horizons. The roots are slightly branched, their sucking power is low. On light soils, individual roots go deep into the soil by 90-100 cm.
In the second or third year of life, one or more hollow flower stems (arrows) are formed from the rudiments of the bulb with a swelling on the lower part. The arrows bear large spherical inflorescences. Inflorescence enclosed in a thin shell (cover), bursting when the flowers bloom (Fig. 69). flowers bisexual, consisting of six white or greenish-white corolla petals, six stamens and an upper ovary. In the inflorescence, the flowers bloom non-simultaneously, so flowering and seed ripening are greatly delayed. In the conditions of the south, the flowering of one inflorescence lasts 10-20 days or more. Onion is a cross-pollinating plant. Pollen is carried by insects, mainly bees. Fetus- trihedral, cracking when ripe box with six (when fully pollinated) black trihedral seeds and a wrinkled surface. The absolute weight of seeds is 2.5-4 g. Normal germination is 95-98%, it lasts for 2-3 years.

Onion is a herbaceous perennial plant that is grown everywhere.

Description of the onion

Bulb onions consists of a membranous bulb, which is usually about 15 cm in diameter. The husk of the bulb is dry on the outside, usually yellow, but sometimes white and purple. The inner scales of the bulb are fleshy, usually white or greenish, but can also be purple, located on a short stem called the bottom. Hollow, tubular, long leaves grow from the bulb, bluish-green in color. During the flowering period, the onion releases a flower arrow, the height of which can reach one and a half meters, this arrow is empty, swollen with a multi-flowered umbrella inflorescence.

Varieties of onions

The Onion family has several varieties that differ from each other not only in appearance, but also in taste. These varieties include:

The bulb consists of a bottom with modified leaves sitting on it - scales and a kidney inside. Outside, the onion bulb is covered with dry scales of various colors. The outer shells of the bulb, which protect it from adverse external influences, in various types of onions can be thick, thin, leathery, membranous, papery, fibrous, mesh, and others.

The structure of the bulb (left - longitudinal section, right - transverse):

1 - dry integumentary scales; 2 - open juicy scales; 3 - closed juicy scales; 4 - rudiments; 5 - bottom; b - heel; 7 - neck.

Longitudinal section of onion bulbs differing in the number of primordia:

1 - single germ; 2 - bisexual; 3 - multigerm; 4 - arrow bulb: a - arrow, b - sighting bulb.

Bulbs can be of various sizes - from 5 ... 20 grams to 800 grams, as well as various shapes.

Bulb shapes of various varieties of onions: flat, round-flat, round, melon, elongated-melon and long.

The structure of the flowering shoot. The flower-bearing shoot of the onion is called the peduncle or flower arrow. The peduncle develops when the formation of the leaves is completed and they begin to die off. The arrow emerges from the false stem in the axil of the last leaf. Bows have a green flower arrow. Due to its photosynthetic activity, the formation and filling of seeds is ensured.

The structure of flowers. Onion flowers have a regular symmetrical shape, without a calyx. There are six petals in the corolla of a very diverse color - white, yellow, greenish, pinkish, blue, purple. Often the petals have a dark central vein. Stamens six, pistil one. The anthers of the stamens, as well as the petals of the corolla, have a different color, and the pedicels also have a different color. Nectaries are located at the base of the onion ovary. The flowers of some species, such as the fragrant onion, have a pleasant aroma, completely different from the usual pungent smell for onions.

The structure of the fetus. The fruit of the onion is a dry three-celled box in which up to six seeds can form, but two to four are more often tied. Seeds are black (they are sometimes called nigella), irregularly triangular in shape, covered with a hard horn-shaped shell, which protects the seeds well from adverse effects.

Onion flower and fruit:

a - a flower during flowering; b - seed box when pouring seeds; c - an opened box with a seed.

The structure of the onion is slightly different from the plants we are used to. It does not have a clear division into stem and leaves, stem and rhizome. The lower parts of the leaves are tubular sheaths from which false stems are formed. bases of false stems thicken and form a bulb. In the middle of the bulb is the growing point or bud.

onion roots

Bow roots are very weak, like strings. They branch little and have few root hairs. Air dry very quickly. New roots appear in the process of growth along the periphery of the bottom. Onion roots penetrate to a depth of 50 cm, most of them are in the surface layer of the soil. For good growth, they need a short daylight hours and a temperature of + 5-10 degrees, as well as air, so the onion is very responsive to loosening. To the sides, the roots extend up to 30 cm. Do not eat onion roots. Perennial bows often have rhizomes. This is not a root, but a modified stem that is in the soil. On the rhizome are buds that give rise to new shoots.

onion stalk

The stalk of the onion is greatly shortened and is called the bottom. Leaves, feathers grow from the bottom, bulb scales form. On the bottom there are also the beginnings of leaves - buds or growth points. They are located on the bottom in a spiral during the growing season. Each bud can form a bulb or peduncle with inflorescences. Green leaves dry in the middle part to form a false stem. It is supported by young green leaves growing from within.

onion leaves

Onion leaves are tubular or tubular, hollow inside or flat, of various shapes and sizes. For example, onion leaves are fistulate, while garlic has a flat linear leaf. The more leaves, the larger the bulb. The first leaf of all onions is fistulate, hollow inside. Onion leaves are formed from the kidney alternately. As the base of the leaves grows, they thicken and turn into fleshy scales. The middle part of the leaves into a false stem, which dries up in autumn and turns into a neck. If the neck of the bulb has become thin and dry, then the bulb is ripe. The outer leaves of the bulb dry out and turn into the shell of the bulb.

onion bulb

The onion bulb consists of a bottom and strongly thickened bases of leaves, called scales. In the axils of the scales are the rudiments. Leaves grow from each primordium, and then a flower arrow. Bulb primordia is a varietal trait. The outer shells of the bulbs are different for different onions - thick, thin, mesh, leathery, membranous, etc. Their color is also very diverse - white, gray, brown, dark red, purple, yellow. The structure of the onion and its bulb depends on the type of onion.

Bulbs are real and false. Real ones have closed scales, while false ones do not. Onion bulbs are prefabricated, like garlic. Some types of onions form only false bulbs, without a neck, elongated. It happens that onions form on the bottom - babies.

Bow flower arrow

The flower arrow of the bow is up to 1m or more. In the middle, the arrow usually expands and narrows again at the end. Swelling on the flower arrows of the onion helps to increase the resistance of peduncles to lodging. At the end of the arrow is an inflorescence - a spherical simple multi-flowered umbrella. The shape and number of flowers in an umbrella depends on the type of plant. The diameter of the inflorescence is from 5 to 15 cm. The duration of flowering of individual flowers in the middle lane is 5-7 days. In total, the onion inflorescence blooms from 15 to 35 days.

onion fruit

The onion fruit is a dry trihedral box with 2-3 (up to 6) black, hard seeds. Seeds of irregular trihedral shape, covered with a hard wrinkled shell. They are often called chernushka. According to biological characteristics, onion seeds can be divided into three groups.

1. Seeds that do not have a dormant period. They can germinate at any time at temperatures from +3 to +35 degrees. These are the seeds of onions and onions - batun.

2. Seeds that have a dormant period. They are sown only before winter.

3. Seeds with extended germination period. Onion species with such seeds are well adapted to survive in harsh conditions, because if seedlings of one germination period die due to adverse conditions, then the species survives at the expense of seedlings of other periods. The seeds of this group are also sown before winter.

There are many types of onions. There are wild and grown in the garden. But all of them are united by the similarity of leaves, bulbs, inflorescences. The botanical structure of onions in different species is the same.

Subject: "Structure, features of growing onions"

Target:- to acquaint with the structure of onions and the features of cultivation.

Tasks:

Educational.

1. To study the structure of onions.

2. To study the features of growing onions.

Correction-developing.

1. Contribute to the formation of an active perception of the lesson material through the use of visual material + practical exercises.

2. Promote the development of memory through the assimilation of new terms.

3. Contribute to the development of logical thinking through the use of didactic material.

Educational.

1. To cultivate independence in educational activities.

2. To cultivate discipline, love for work.

visibility.

Individual task cards, materials for practical tasks (onions, seeds, etc.), illustrations + posters.

During the classes.

I. Organizational moment.

-Emotional mood of children (smile at each other).

- Corrective exercise.

Purpose: - the mood of auditory perception.

Did you all hear the call?

May I start the lesson?

Mood for five?

Do you want to know something new?

Let's sit quietly at our desks now,

And I will start the lesson for you.

Purpose: to consolidate the knowledge that students have

Send your good work in the knowledge base is simple. Use the form below

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