What parts of the shoot does the bulb have. Aboveground and underground modifications of shoots. The root system of different types of onions

Bulb bottom

the axis of a shortened shoot flattened into a plate, which, together with its fleshy-thickened leaves, forms an onion.

encyclopedic Dictionary F. Brockhaus and I.A. Efron. - St. Petersburg: Brockhaus-Efron. 1890-1907 .

See what the "bottom of the bulb" is in other dictionaries:

Onion bulb (Allium cepa) L. Botanical illustration from the book of Martin Chilenšek (Slovenian Martin Cilenšek) Naše škodljive rastline, 1892 Bulb (lat. búlbus) is a modified, usually underground shoot of plants with a thickened short ... ... Wikipedia

bottom- a shortened and thickened stalk of a bulb, a corm... Plant anatomy and morphology

DONCE- the stem base of the bulb, usually disc-shaped or cone-shaped, with very shortened internodes and modified leaves ... Glossary of botanical terms

The subfamily Liliaceae proper (Lilioideae) has 10 genera (approximately 470 species) belonging to 4 tribes. Representatives of the subfamily are found only in the northern hemisphere. Their bulbs are composed of lower scales, since the basal ... ... Biological Encyclopedia

- ... Wikipedia

Squill- Urgenia maritima L. The lily family A perennial powerful bulbous plant, the leafless flower arrow of which reaches a height of 100-150 cm. The roots are fibrous, extending from the bottom of the bulb, thick and strong, with thin lateral branches ... Encyclopedia of Medicinal Plants

Probably, everyone knows such ornamental plants as iris, or iris (Iris, tab. 23, 24), skewer, or gladiolus (Gladiolus, tab. 26, 3), and saffron, or crocus (Crocus, tab. 25) ... Biological Encyclopedia

Royal Lily ... Wikipedia

bulb of a flowering plant- The bulb is a modified shoot. The bottom of the bulb is a strongly shortened stem, the scales are modified leaves. Around the bottom are the rudiments of roots that develop when the bulb is planted in the ground. At the very bottom inside the bulb ... ... Official terminology

NECK ROT- see Neck rot disease caused by a fungus. Gray depressed spots appear near the neck of the bulb, which later spread to the scales and the bottom of the bulb. The fungus persists on bulbs, in soil and on plant debris until ... ... Encyclopedia of seeds. vegetable crops

>>Rhizome, tuber, bulb

§ 37. Rhizome, tuber, bulb

Peculiar underground pantries have perennial herbaceous plants. The above-ground parts of these plants die off annually by autumn. IN soil roots and modified underground shoots remain. They don't look like regular overhead ones. It is in these modified shoots that reserves of organic matter are deposited for the winter. Modified shoots are rhizomes, tubers and bulbs.

The rhizome is found in nettle, couch grass, iris, lily of the valley, houseplant aspidistra.

If you dig the rhizome of any plant out of the ground, you can see that outwardly it resembles root . But the rhizome, like the above-ground shoots, has apical and axillary buds, as well as membranous scales - modified leaves. Adventitious roots grow from the rhizome 72. From the apical or axillary buds of the rhizome, young above-ground shoots develop in spring. At the same time, they use the nutrients deposited in the rhizome in autumn. If a piece of rhizome with a bud and adventitious roots is planted in the soil, a new, independently existing plant . Some perennial ornamental plants reproduce by dividing the rhizome into parts.

Tubers are characteristic of a few plants, for example, for potatoes . Underground shoots, on the tops of which tubers develop, grow from the bases of above-ground stems; these shoots are called stolons. Tubers are apical thickenings of stolons 73 . The tuber has short internodes; it does not contain chlorophyll, but when exposed to light, it can turn green.

Consider a potato tuber.

On its surface, in depressions of 2-3, there are buds, or eyes. There are more eyes on that part of the tuber, which is called the top. The opposite side - the base - the tuber is connected to the stolon. The structure of the potato tuber convinces that the tuber is a modified underground shoot 74 .

Organic matter constantly flows from potato leaves through the stems into stolons and in the form starch deposited at the top.

The tops of stolons grow, thicken and turn into large tubers by autumn. Cut a tuber and put a drop of a weak iodine solution on it. You will make sure that there is starch in the tuber.

Some wild plants also have tubers, for example, Corydalis and Jerusalem artichoke forage plant.

At the bottom of the bulb onion an almost flat stem is located - the bottom.

On the bottom are modified leaves - scales. The outer scales are dry, leathery, while the inner scales are fleshy and juicy. They contain water reserves, as well as sugar and other substances dissolved in it. Buds located in the axils of scales 75 are visible on the bottom. Thus, the bulb is a modified shoot.

If the bulb is planted in the ground, a fibrous root system grows from the underside of the bottom. Sometimes young bulbs, called children, develop from the kidneys. An independent plant can grow from each bulb of a baby.

Bulbs form onions, lilies, tulips, daffodils, wild goose onions. All of them are perennial.

1. What modified underground shoots do you know? Name plants that have a rhizome, tuber, bulb 72, 73.
2. How to distinguish a rhizome from a root?
3. How does a potato tuber develop?
4. Why should a potato tuber be considered a shoot?
5. What is the structure of the bulb?
6. How to prove that the rhizome and bulb are a modified shoot?

1. Place an onion bulb in a jar with a narrow neck so that the bulb does not fall through, but only touches the bottom of the water poured into the jar. After a few days, the bulb will develop adventitious roots and green leaves. Why does the bulb grow, although it is not in the soil, but in the water?

2. With the onset of warm spring weather, watch the flowering of wild bulbous and rhizomatous plants. 3. Watch the development of woody shoots and sprouting tubers 76, 77 . Compare them and draw your own conclusions.

Korchagina V.A., Biology: Plants, bacteria, fungi, lichens: Proc. for 6 cells. avg. school - 24th ed. - M.: Enlightenment, 2003. - 256 p.: ill.

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Underground shoots, like aboveground ones, are modified, adapting to environmental conditions. Roots can also often take on an unusual appearance.

Shoot modifications

Some plants have underground shoots. An underground shoot differs from a root in the preservation of signs. Like any shoot, the underground one has nodes and internodes, and on the nodes there are leaves (even if they are small and colorless). In the axils of the leaves of the underground shoot there are lateral buds, and on its top - the apical bud.

There are three main types underground shoots: rhizome, tuber and bulb.

Rhizome outwardly resembles. Adventitious roots grow from it, and above-ground shoots develop from the apical or axillary buds in spring. The rhizome has lily of the valley, coltsfoot, couch grass, nettle.

Tuber- this is the apical thickening of underground shoots (stolons), in which starch is stored. On the surface of the tuber in the recesses there are 2-3 buds, called "eyes". There are more of them at the top of the tuber. Tubers are formed in earthen pears, potatoes.

Bulb- this is a shoot with a very short flat stem, called the "bottom" and succulent with a supply of nutrients, called scales. The outer scales of the bulb are usually leathery. Above-ground green leaves and an arrow develop from the upper kidney of the donets. Bulbs are formed in onions, tulips, daffodils. Most bulbous plants live in the steppes, where in a short wet period they have time to develop green leaves, bloom and form a fruit due to reserve substances in the scales.

Root modifications

Root modifications are very diverse. In some plants, reserve nutrients are deposited in the roots. Such roots grow strongly in thickness and acquire an unusual appearance. If reserve substances accumulate in the main root, root crops are formed. If reserve substances accumulate not in the main, but in adventitious roots, then root tubers are formed.

On swampy, oxygen-poor soils in the tropics, trees form respiratory roots. They rise above the soil surface and supply the underground organs with air through special openings.

Trees growing along the seashores develop stilted roots. They perform a supporting function, help the trees to maintain stability on shaky ground.

Plant seeds usually germinate when they fall into the ground at some depth. The very first shoot growing from the bud of the embryo must break through the soil. The first adventitious roots usually grow on this underground part of the stem. They can pull the base of the stem into the soil even deeper than it was originally immersed. Unlike rhizomes and tubers, bulbs have well developed leaves and a very short and flat stem. It is called "donets".

At the top of the bottom, under the cover of scales, there is a kidney, from which grows elevated escape. From the axillary buds located below the apical, new "daughter" bulbs are formed. From each daughter bulb - "kids" a new plant can grow.

What to do. Consider external structure bulbs.