It has a rudimentary stem with a growth cone and rudimentary leaves. The flower bud contains rudimentary flowers. The outside of the buds is covered with bud-like scales. After a period of rest, the buds open. The expansion of shoots from the buds is associated with the growth of internodes and leaves.

Apical bud

At the top of the shoot there is usually an apical bud.

Lateral bud (axillary)

In the axils of the leaves there are lateral (axillary) buds. Axillary buds are located on the stem alternately (willow, linden, alder, aspen) or oppositely (elderberry, maple, lilac, ash) (Fig. 113).

Accessory buds

Sometimes buds may develop not in the leaf axil, but on the internodes of the stem, roots or leaves. Such buds are called accessory buds.

Overwintering buds

IN temperate latitudes in mid-summer or autumn, in the tropics, with the onset of the dry period, the apical and axillary buds enter seasonal dormancy. In temperate latitudes, such buds are called overwintering or dormant. The outer leaves of these buds turn into dense covering bud scales, almost hermetically covering the inner parts of the bud. Covering scales reduce water evaporation from the surface internal parts kidneys, and also protect the kidneys from freezing, pecking by birds, etc.

Dormant buds

Not all buds laid in the previous year bloom on trees and shrubs. Many axillary buds remain dormant for a long time, sometimes for many years. Such buds are called dormant (Fig. 116). In oak they “sleep” for up to 100 years, in birch - up to 50, in aspen - 40, in honeysuckle - 35, in hawthorn - up to 25 years.

When the apical bud disappears (due to freezing, biting, cutting), the dormant buds begin to grow and grow into elongated shoots. Such shoots especially often develop on oak, elm, maple, rowan, poplar, and apple trees.

Dormant buds have great importance to restore the crown if it is damaged by spring frosts and decorative pruning trees and shrubs. In cities, the crowns of poplars are often severely pruned, leaving only the trunk or several large side branches. In spring, many young shoots appear on the pruned parts of the tree, which develop from dormant buds (Fig. 117).

Based on their structure, buds are distinguished between vegetative and generative (floral).

Vegetative bud

A vegetative bud consists of a rudimentary stem and rudimentary leaves located on it. In the axils of the leaves you can find tiny rudimentary axillary buds. On the outside, the buds are protected by bud scales. Material from the site

Inside the bud at the apex of the stem there is a growth cone consisting of cells of the apical educational tissue. Thanks to the division, growth and change of its cells, the stem grows, new leaves and buds are formed (Fig. 114).

Generative bud (floral)

In the generative (floral) buds on the stem, in addition to the rudimentary leaves, there are the rudiments of flowers or one flower. This is clearly visible in elderberry (see Fig. 114) and chestnut. lilac. The generative buds of many woody plants differ from the vegetative ones in size and shape: they are larger and often rounded.

1. What structure does the seed embryo have?

In the embryo, there are germinal roots, stalks, buds and cotyledons.

2. What kind of fabric is called educational?

Educational tissue consists of small, tightly adjacent living cells that constantly divide.

Laboratory work. The structure of the kidneys. Location of buds on the stem

1. Consider the shoots different plants. Determine how the buds are located on the stem and sketch them.

2. Separate the buds from the shoot and examine them external structure. What adaptations help the kidneys withstand adverse conditions?

From exposure unfavorable conditions external environment The buds are protected from the outside by dense, leathery bud scales.

3. Cut the vegetative bud lengthwise and examine it under a magnifying glass. Using Figure 19, locate the scales, rudimentary stem, rudimentary leaves and growth cone. Draw a cross-section of a vegetative bud and label the names of its parts.

4. Study the generative bud. What do vegetative and floral buds have in common and how do they differ? Use Figure 19 for comparison.

General: the outside of the buds is covered with dense, leathery bud scales that protect them from exposure to adverse environmental conditions. Through a magnifying glass, on a longitudinal section of the bud, the rudimentary stem is clearly visible, at the top of which there is a growth cone. Very small rudimentary leaves are located on the bud stem. In the axils of these leaves there are rudimentary buds.

Differences: Inside some buds on the rudimentary stem there are only rudimentary leaves. Such buds are called vegetative or leaf buds. Generative, or flower, buds are rudimentary buds or inflorescences,

5. Compare the structure of the bud and shoot. Draw a conclusion.

The stem with leaves and buds located on it is called a shoot. The bud also has a stem on which very small rudimentary leaves are located. In the axils of these leaves there are rudimentary buds. Thus, the bud is a rudimentary, not yet developed shoot.

Questions

1. What is an escape? What parts does it consist of?

A shoot is a stem with leaves and buds located on it. The stem is the axial part of the shoot, the leaves are the lateral ones. The sections of the stem on which leaves develop are called nodes, and the sections of the stem between the two nearest nodes of the same shoot are called internodes.

2. What types of leaf arrangement do you know?

Plants have an alternate (spiral), opposite, whorled leaf arrangement.

3. What is a kidney?

A bud is a rudimentary shoot that has not yet developed.

4. How are kidneys distinguished?

Generative, or floral, buds are larger than vegetative ones and have a more rounded shape.

5. How can buds be located on shoots? Establish a relationship between the location of the buds on the shoot and their location.

At the top of the shoot there is usually an apical bud, and in the axils of the leaves there are axillary buds.

The arrangement of axillary buds repeats the arrangement of leaves on the stem. Poplar, cherry, birch, bird cherry, hazel have an alternate arrangement of buds. The buds are located opposite on the shoots of lilac, elderberry, jasmine, honeysuckle and indoor plants fuchsia, pilea, coleus, which are characterized by the same leaf arrangement.

6. What is the structure of a vegetative bud?

Very small rudimentary leaves are located on the bud stem. In the axils of these leaves there are rudimentary buds.

7. How do generative buds differ from vegetative ones?

Generative, or floral, buds, in contrast to vegetative ones, in addition to rudimentary leaves, on the rudimentary stem there are rudimentary buds or inflorescences.

8. How does the shoot grow in length?

The development of the shoot begins with the opening of the buds. When the bud scales fall off, intensive shoot growth begins. The shoot lengthens due to the division of cells of the growth cone (educational tissue). Young cells grow, forming new sections of the stem with leaves and buds. As you move away from the apical point of growth, the ability of cells to divide weakens and is soon completely lost. New cells turn into cells of the integumentary, main, mechanical or conductive tissue of the shoot, depending on their location.

Think

When the average daily temperature rises above +5°C, plant vegetation begins, accompanied by active spring sap flow, that is, the supply of water with nutrients dissolved in it from the roots up through the vessels of the wood. At the same time, the speed of water movement is woody plants amazingly large: about 40 cm per minute. This means that in 5 minutes the water in the vessels rises to a height of two meters. The intensity of spring sap flow can be judged by the release of the well-known birch sap.

If trees are pruned before sap flow begins, the surface of the cuts is dry and the putty easily sticks to it. And when pruning, it is wet during sap flow, so the putty does not stick well. After some time, the juice will begin to gush out, rejecting the garden varnish.

"Weeping" trees are needlessly depleted. In addition, the juice flowing down the bark becomes a breeding ground for various harmful microorganisms. In particular, it settles here sooty fungus, due to which the surface of the trunk and branches turns black. At the same time, the bark stomata are clogged, air exchange is disrupted, which is why the trees look oppressed, and subsequently their natural winter hardiness decreases.

Tasks

1. Place a branch of a tree or bush in the water and watch the development of shoots from the buds. Write down when the branch was placed in water, when its buds swelled, its scales opened, a shoot appeared and leaves blossomed.

2. Sprout two bean or pea seeds in a pot of soil. When the stems of the plants reach 7-10 cm in height, cut off the top of one of them. Observe what happens to the plants after one to two weeks.

3. Trim the top of a ficus or other indoor plant. Watch the shoots grow.

4. Analyze the results of your observations. Draw conclusions.

If you remove the apical bud, the shoot stops growing in length, but it develops side shoots. If you cut off the top of a side shoot, it will also stop growing in length and begin to branch.

The human body is a reasonable and fairly balanced mechanism.

Among all known to science infectious diseases, infectious mononucleosis has a special place...

About the disease that official medicine calls “angina pectoris”, the world has known for quite a long time.

Pig ( scientific name- mumps) is called an infectious disease...

Hepatic colic is a typical manifestation of cholelithiasis.

Brain edema is a consequence of excessive stress on the body.

There are no people in the world who have never had ARVI (acute respiratory viral diseases)...

A healthy human body is able to absorb so many salts obtained from water and food...

Knee bursitis is a widespread disease among athletes...

A vegetative bud is

Vegetative buds

Based on the structure and nature of the neoplasms grown from them, buds are distinguished into vegetative, generative and vegetative-generative (mixed).

Vegetative buds form shoots during germination. They are thinner than generative ones and have a pointed apex.

Generative (flowering) buds upon germination produce only flowers or inflorescences. In the place where the flower bud was, after harvesting, only scars remain and the branch is exposed. Generative buds are present in all stone fruits, as well as in red and white currants, citrus fruits, hazelnuts, and oriental medlars. In nut-bearing species, earrings are formed from simple buds ( male flowers).

Vegetative-generative (mixed) buds are most often formed on the tops of shoots and less often on the sides. They have the rudiments of flowers and shoots. When they germinate, fruit bags with flowers (inflorescences) are formed, and then fruits and replacement shoots. They are characteristic of all pome-bearing species, black currants, gooseberries, raspberries, figs, persimmons, and walnuts.

According to their position on the shoot, apical (final, terminal), lateral, or axillary (axillary) and adventitious buds are distinguished.

The apical buds are usually solitary.

Axillary buds are formed in the axils of the leaves and can be single or group (two or three well-developed buds). The latter are typical for peach, apricot, almond, plum, and cherry plum.

In many species, one bud is clearly visible in the leaf axil, and one or two are faintly noticeable or invisible, as they are hidden in the bark of the stem. They are called submerged or spare.

Based on the time of awakening, normal, early ripening, dormant and adventitious buds are distinguished.

Normal buds germinate the next year after they are laid.

plodyagoda.ru

Structure and functions of fruit plant buds

The embryonic shoot and its modifications in a state of relative dormancy are called buds.

The bud is an organ of growth, renewal and vegetative propagation (Encyclopedia of Gardening, 1990). Kidneys fruit plants differ from each other in structure and function, location on the stem and time of germination.

According to the structure and functions of the kidneys, there are vegetative and generative.

A vegetative (growth) bud is a shortened shoot consisting of an axis, a cone, the growth of leaf primordia and covering bud scales. Vegetative buds are smaller, more elongated and pointed than generative ones. After germination, vegetative buds produce shoots various lengths.

Generative (flowering, fruiting) buds contain flower primordia, and in a number of breeds and vegetative organs- leaves and growth buds. In this regard, in their structure, generative buds are simple and mixed (vegetative-generative).

Simple generative buds have well-developed flower primordia, from which only flowers and fruits develop. After fruiting, only a scar remains in place of a simple flower bud. Such buds are characteristic mainly of stone fruits.

Mixed (vegetative-generative) buds have full-fledged primordia of flowers, inflorescences, leaves and stems. From one such bud, generative organs, as well as leaves and shoots, are formed. They are characteristic of pome-bearing species. Generative mixed buds are larger and rounded compared to vegetative ones.

Knowing features generative buds, you can predict next year’s harvest and correctly regulate the crop load of trees when pruning.

Depending on their position on the stem, the buds are apical (terminal, terminal) and lateral (stem, collateral).

Most often, the buds are located at the top of the stem and in the axils of the leaves, singly, sometimes in pairs or three. If several buds form in the leaf axil, they are called serial if they are located one under the other (walnut), and collateral if they are located side by side (peach).

From total number As a rule, only a few axillary buds formed on the plant subsequently develop. One part of the axillary buds dies completely, and the other freezes for an indefinitely long time, turning into so-called dormant buds, which begin to grow if the main bud dies.

The buds formed on the stems of different breeds and varieties germinate into different times. Depending on the time of germination, the buds are divided into early ripening, normal (late ripening) and dormant.

Early ripening buds under normal conditions germinate in the year of formation and, as a rule, produce premature shoots.

Normal (late-ripening) buds under normal conditions germinate and produce new growths the next year after formation.

Dormant buds are underdeveloped and remain outwardly long time inactive (apple trees are up to 20-25 years old). Their axis lengthens annually as the branches thicken. As a result, the bud maintains a superficial position on the stem. In pome-bearing species, dormant buds are more durable (they live up to ten years), while in stone fruit species they are less durable, especially in cherries. They can begin to grow if the apical bud is removed, or if it dies on its own. Of particular note are the dormant buds in the trunks fruit trees, immersed in wood, overgrown with it and growing from the cambium as the trunk thickens. After breaking or cutting the trunk above them, they “wake up”, forming shoots.

If you find an error, please select a piece of text and press Ctrl+Enter.

In contact with

Classmates

www.activestudy.info

How does a vegetative bud differ from a generative one?

In any gardening encyclopedia or biology textbook you can find a chapter devoted to buds - the organs of growth, renewal and vegetative propagation of plants. The rudimentary shoot has several modifications. The buds of fruit plants are usually divided into vegetative and generative according to function and structure. What is the difference between them?

A vegetative or growth bud is a shortened shoot consisting of an axis, a cone, the growth of leaf primordia and covering bud scales. Externally, vegetative buds are distinguished by their smaller size, elongated and pointed shape. After germination, shoots of varying lengths are obtained.

Generative, or otherwise flowering, fruit buds contain the rudiments of flowers. In some varieties of plants - leaves and growth buds. For this reason, according to their structure, generative buds are divided into simple and mixed (vegetative-generative).

Simple generative buds contain perfectly developed flower primordia, from which only flowers and fruits grow. At the end of fruiting, only a scar remains at the site of such a shoot. Most often, simple generative buds are found in stone fruit trees.

Mixed (vegetative-generative) buds contain complete primordia of flowers, inflorescences, leaves and stems. From one such bud, generative organs, leaves and shoots are formed. Mixed buds are most often found on pome-bearing plants. Externally, they are larger and rounded than vegetative ones.

Stems and leaves grow from the vegetative bud.
Generative ones contain flower primordia.
Vegetative buds are smaller in size, elongated and pointed in shape.
Simple generative buds are found in stone fruit trees, mixed ones - in pome trees.

Encyclopedia of Gardening, 1990

thedb.ru

2. Types of plant buds, their structure. Plastochron

A bud is an embryonic shoot, its structure.

When a seed germinates, a shoot develops from the bud of the seed embryo. U perennial plants the shoot starts from a bud. A bud is an embryonic shoot. It consists of a shortened stem with closely spaced rudimentary leaves. At the top of the stem there is a growth cone consisting of educational tissue. Due to the division of cells of the growth cone, the stem grows in length, the formation of leaves and outer buds. Externally, the kidney is protected by renal scales, which are modified lower leaves escape. Depending on their location on the shoot, the buds can be apical or lateral.

This is the bud located at the top of the shoot, the rest of the buds are lateral. They are divided into axillary and accessory.

regularly appear in the axils of young leaf primordia near the tip of the mother shoot. Their arrangement exactly corresponds to the leaf arrangement. Therefore, in winter, the location of the leaves can be determined by the buds.

that develop outside the axil on internodes, roots and leaves are called adventitious. They often provide vegetative propagation plants. Adventitious buds on the leaves immediately develop into small plants with adventitious roots, which fall off the leaf of the mother plant and grow into new individuals. These buds are called brood buds (bryophyllium, sundews). They can appear in the leaf axil and change into bulbs (tiger lily) and nodules (viviparous knotweed).

The kidneys are not the same in structure. In most plants they are closed (protected), because on the outside they have bud scales, glued together with resin (in conifers), other adhesive substances (poplar), some are often omitted. There are plants with open (unprotected, bare) buds. They lack bud scales (viburnum, buckthorn).

Based on their internal structure, the following types of kidneys are distinguished:

1) vegetative - consist of a rudimentary stem, scales, rudimentary leaves and a growth cone;

2) generative - floral, consisting of a rudimentary stem, scales and primordia of a flower or inflorescence (red elderberry);

3) mixed - consist of a rudimentary stem, scales, rudimentary leaves and rudiments of a flower or inflorescence (apple tree, spirea).

Generative and mixed buds are larger and more rounded than vegetative ones.

Buds that remain dormant (autumn - winter) and then unfold and produce new shoots are called overwintering or renewal buds. Due to them, shoots grow.

Dormant buds - they remain dormant for a number of years. The stimulus for their awakening is damage to the trunk.

Plastochron - The time interval between the beginning of two successively repeating events, such as the initiation of a leaf primordium, the achievement of a certain stage of leaf development, etc. Varies in duration if measured in units of time. (the period of time between the formation of two successive metamers by the shoot apex)

Ticket No. 15

1. Rhizome and methods of its formation. Caudex, underground stolons and tubers.

A rhizome is a horizontally growing underground perennial shoot with remnants of dead leaves, buds and adventitious roots. Spare parts are usually deposited in the rhizome. nutrients, however, the degree of its specialization as a storage organ in different types different. In addition, the rhizome serves for vegetative propagation of the plant. When artificially propagated, it is usually divided after flowering. At this time, the rhizome is in a state of readiness for further growth and the formation of new roots.

Rhizomes can grow in two ways. In the German (garden) iris, the apical bud develops into a peduncle, and growth in the horizontal plane is carried out due to the lateral bud. In the next season, this resulting lateral shoot forms its own apical bud, forming a peduncle, and the plant continues to grow horizontally, laying new lateral buds. In another case, as in mint or wheatgrass, the growth of the rhizome is carried out due to the prolonged functioning of the apical and sometimes lateral buds, which usually produce flowering shoots.

In general, the rhizome can be a monopodium (for example, in raven eye) or sympodium (for example, in kupena), if during growth there is a regular reversal.

When rhizomes branch, forming several daughter rhizomes, a clump of above-ground shoots is formed, which actually belong to one individual, while they are connected by underground “communications” - sections of the rhizome system (for example, in lily of the valley, hairy sedge, sedge, wheatgrass, etc.). If the connecting parts are destroyed, then the individual parts of the rhizome system are separated and vegetative propagation occurs (see Fig. 327).

A set of new individuals formed from one by vegetative means is called a clone. Rhizomes are characteristic mainly of herbaceous perennials, but they also occur in shrubs (euonymus) and dwarf shrubs (lingonberries, blueberries, Fig. 326). The lifespan of rhizomes varies widely - from two or three to several decades.

Two ways to form rhizomes. Plants - lungwort - form sympodially growing rhizomes from the lower parts of shoots in successive orders. However, you can notice a very significant difference in the course of their formation. In lungwort, initially the entire shoot is aboveground; it bears scale-like and green rosette leaves. Subsequently, the leaves die, leaving scars, and the stem part with the help adventitious roots is drawn into the soil and turns into a rhizome, which thickens due to the deposition of reserve starch in the parenchyma. Each section of the rhizome (sympodium segment) lives 5-6 years.

Thus, in the structure and life activity of the same section of the shoot, two phases can be distinguished: aboveground and underground; During the first, the shoot mainly photosynthesizes; during the second, it serves as a storage organ that promotes overwintering and regeneration with the help of the buds. During ontogenesis, the shoot undergoes a real transformation, metamorphosis in the literal sense, with a change of functions, and this transformation of a leaf-bearing shoot into a rhizome occurs quite late; completely adult organs metamorphose. Such rhizomes can be called submersible or epigeogenic (Greek epi - above; ge - earth; gennao - produce, form; epigeogenic - above-earthly born).

Exactly the same picture is observed during the formation of rhizomes in very many plants, for example, in the hoofed grass, amazing violet, strawberry, mantle, and gravilata. In the last three cases, the shoot or their system gradually sinking into the soil bears only regularly changing green leaves of the middle formation, without forming scales at all. The rhizome is covered with dry, filmy yellowish and brown bases of dead green leaves - stipules.

Submerging rhizomes are not always sympodial; in a number of plants these are typical monopodia (cuff, gravilate, greenweed, etc.).

Develops in perennial herbs and shrubs with well-developed tap roots. This is a kind of perennial organ of shoot origin - usually lignified lower sections of shoots, turning into a woody tap root.

The caudex bears numerous renewal buds. In addition, the caudex usually serves as a place for the deposition of reserve nutrients. As a rule, the caudex is underground and, quite rarely, aboveground.

The shoot origin of the caudex can be determined by leaf scars and the regular location of the kidneys. Caudex differs from rhizomes in the way it dies. Gradual death occurs from the center to the periphery, while the organ divides (cracks) longitudinally into separate sections - particulates. Accordingly, the process of division is called particulation. As a result, a structure is formed, which is often called: multi-headed rhizome, knobby rhizome, multi-headed stem rod, stem root. These names quite accurately reflect the appearance of the caudex and create its image.

It should be noted that particulation is characteristic of old (cyanyl) plants.

The caudex is especially pronounced in semi-desert, desert and alpine plants. In some species, caudexes reach enormous size and weight, for example, in representatives of the genus Pangos up to 15 kg.

Systematically, there are many caudex plants among legumes (alfalfa), umbelliferae (female), and Asteraceae (dandelion, wormwood).

Underground stolons and tubers

Tubers are thickenings of underground shoots like potatoes and Jerusalem artichokes. Tuberous thickenings begin to develop at the ends of underground stems - stolons. Stolons are short-lived and are usually destroyed during the growing season, which is why they differ from rhizomes.

In tubers, predominantly parenchyma cells of the core grow. Conductive tissues are very poorly developed and are noticeable at the border of the pith and cortex. The outside of the tuber is covered with a periderm with a thick layer of cork, which helps withstand long winter dormancy.

The leaves on the tuber fall off very early, but leave scars in the form of so-called tuber eyes. Each eye contains 2-3 axillary buds, of which only one germinates. Kidneys at favorable conditions They germinate easily, feeding on the reserve substances of the tuber and growing into an independent plant.

Thus, the third leading function underground shoots≈ vegetative regeneration and reproduction.

Some plant species produce very distinctive leaf tubers (e.g., thin-leaved core). These are modified leaf blades sitting on the petioles of rhizomes. These leafy tubers have lobes, pinnate veining, and even mesophyll tissue, but are achlorophyll-free and adapted for storing storage starch.

The embryonic shoot and its modifications in a state of relative dormancy are called buds.

Bud- an organ of growth, renewal and vegetative propagation (Encyclopedia of Gardening, 1990). The buds of fruit plants differ in structure and function, location on the stem and time of germination.

According to the structure and functions of the kidneys there are vegetative And generative.

Vegetative (growth) bud is a shortened shoot consisting of an axis, a cone, the growth of leaf primordia and covering bud scales. Vegetative buds are smaller, more elongated and pointed than generative ones. After germination, vegetative buds produce shoots of varying lengths.

Generative (flowering, fruiting) buds contain the rudiments of flowers, and in a number of species and vegetative organs - leaves and growth buds. In this regard, in their structure, generative buds are simple and mixed (vegetative-generative).

Mixed (vegetative-generative) buds have complete rudiments of flowers, inflorescences, leaves and stems. From one such bud, generative organs, as well as leaves and shoots, are formed. They are characteristic of pome-bearing species. Generative mixed buds are larger and rounded compared to vegetative ones.

Knowing the distinctive features of generative buds, you can predict next year’s harvest and correctly regulate the crop load of trees when pruning.

Depending on their position on the stem, the buds are apical (terminal, terminal) and lateral (stem, collateral).

Of the total number of axillary buds formed on a plant, as a rule, only a few subsequently develop. One part of the axillary buds dies completely, and the other freezes for an indefinitely long time, turning into so-called dormant buds, which begin to grow if the main bud dies.

The buds formed on the stems of different breeds and varieties germinate at different times. Depending on the time of germination, the buds are divided into early ripening, normal(late ripening) and sleeping.

Early ripening buds under normal conditions, they germinate in the year of formation and, as a rule, produce premature shoots.

Normal (late-ripening) buds under normal conditions they germinate and produce new growths the next year after formation.

Dormant buds are underdeveloped and outwardly remain inactive for a long time (in an apple tree up to 20-25 years). Their axis lengthens annually as the branches thicken. As a result, the bud maintains a superficial position on the stem. In pome-bearing species, dormant buds are more durable (they live up to ten years), while in stone fruit species they are less durable, especially in cherries. They can begin to grow if the apical bud is removed, or if it dies on its own. Of particular note are the dormant buds in the trunks of fruit trees, immersed in the wood, overgrown with it and growing from the cambium as the trunk thickens. After breaking or cutting the trunk above them, they “wake up”, forming shoots.

In plants? This is an organ that is located on the stem in the axil of the leaf or at its apex. In our article we will look at the structural features of this part of plants, the types and the role it plays in their life.

Plant bud: definition

This plant organ is special kind escape. From it a flower or leaves develop. Therefore, it would be correct to say that a bud is the embryonic shoot of a plant.

How is it formed? One of the parts of the seed embryo is the bud. It contains all the parts of the leafy plant, but they are greatly shortened. The bud consists of a stem on which there are closely spaced rudimentary leaves.

The cells of the meristem, or educational tissue, form a growth cone. Due to the division of its cells, the stem grows in thickness, new leaves and outer buds appear.

Types of plant buds

Plant shoots are distinguished by their diversity. Since the bud is a rudimentary version of this organ, several types of this part of the plant are distinguished.

What features are the basis for this classification? These are the features internal structure, location on the stem and physiological state. Let's look at each of these types in more detail.

Location on the plant

Based on this characteristic, apical and lateral buds are distinguished. How to distinguish them? The shoot has only one apical bud. It is the highest on the branch, so finding it will not be difficult. Such a bud represents the rudiment of a young shoot and is a continuation of the main axis. As it develops, it will give rise to new branches and ensure shoot growth in length. Initially, it is formed from the bud of the seed embryo. If the shoot begins to branch, it dies.

All other buds located on the stem are lateral. They come in two types: accessory and axillary. The first ones develop on internodes. This is the name given to the distance between the places where leaves are attached to the shoot stem.

Sometimes adventitious buds form on leaves or roots. In this case, adventitious buds provide vegetative propagation of the plant. For example, in Kalanchoe such structures are located along the entire edge leaf blade. From them small plants are immediately formed, consisting of green shoots with adventitious roots. They fall away from the mother's body and move on to independent existence.

What is a bud in a plant called cabbage? This is her head of cabbage, or fork. It is an overgrown apical bud, which consists of a shortened stem and wide leaves.

Axillary buds are located where the leaf attaches to the stem. They are constantly formed as the plant grows. Their formation occurs in the axils of young leaves. They persist in winter. During this period, the type of leaf arrangement can be determined by the nature of their attachment.

A special type of axillary buds are brood buds. Modified shoots - nodules or bulbs - are formed from them.

Features of the internal structure

What a bud is in plants can be considered using the example of their anatomical features. Based on this characteristic, three types of embryonic shoots are distinguished: vegetative, generative and mixed.

In the first case, a shoot develops from the bud. Therefore, the parts of such a structure are the rudimentary stem, leaves, scales and growth cone. Each of them performs its own functions. The stem and leaves give rise to new organs. The growth cone is the growing point or tip of the stem. It consists of young and constantly dividing cells of educational tissue.

Bud scales are modifications of the outer leaves. They perform a protective function, protecting internal structures from negative manifestations environment. This is mainly hypothermia, the action of direct sun rays and excessive moisture loss. The scales do not contain chloroplasts, so they do not carry out photosynthesis. They are formed by dead cells of cork tissue. When they fall off, they leave scars on the stem. By counting their number, you can determine how many years I will run.

Generative buds give rise to flowers. Their structure differs from vegetative ones. In addition to a shortened stem and scales, they also contain flower rudiments. Some plants develop mixed buds. They contain the rudiments of both future leaves and flowers. Generative and mixed buds are easy to distinguish. They have a round shape and are much larger than vegetative ones.

The kidneys may differ in a number of other characteristics. For example, in spruce and pine the scales stick together using resin, and in poplar - a special adhesive substance. They may be with additional pubescence or bare. And in viburnum, bud scales do not develop at all.

Physiological state

What are buds in plants whose organs do not die off in frosty winters or dry summers? And do they even persist during such unfavorable periods? Undoubtedly. Such buds are called dormant. Such structures ensure long-term periodic growth of plants. In winter they are dormant, with the onset sunny days give new shoots. U annual plants such buds are not formed.

There is another type of embryonic shoots. These are dormant buds. They are living, but may not develop throughout the life of the plant. How can they be “forced” to do this? You just need to remove the part of the stem that is located above the dormant buds. In this case, they will give rise to young shoots. Thus, the development of dormant buds occurs as needed. It can lie dormant for a long time or immediately give rise to new shoots.

Functions of plant buds

The embryonic shoots contain all the organs of the aboveground part of the future plant organism. Therefore, the main function of the kidneys is to carry out its growth and development. U angiosperms they also ensure the formation of a flower, and therefore sexual reproduction.

Kidneys can also be located on modified organs. A typical example of this is potato tubers. The buds of this modification of the shoot are called ocelli. Their function is vegetative propagation.

We are sure that now everyone will be able to answer the question of what a bud is in plants. This is a rudimentary and shortened shoot from which stems, leaves and flowers develop.