Buds on plants are presented in 2 main varieties - vegetative and generative. What is the specificity of both of their varieties?
What is a vegetative bud?
Any bud is the germ of a shoot of a plant. As a rule, it is formed in the axil of the leaf or in the terminal part of the shoot. Sometimes buds form on stems and roots. The vegetative shoot primordium includes the rudimentary stem and leaves.
Vegetative bud
The plant bud in question can be formed from a dormant bud that forms on a tree branch. Shoots grow from appropriate primordia during various stages of the growing season - for example, in spring.
What is a generative kidney?
This type of bud is the germ of a shoot, from which flowers and inflorescences of plants then grow. In principle, cases of formation of sections of stems or leaves from generative buds are possible (their rudiments are also present in the structure of the corresponding bud of some plants).
Generative kidney Comparison
The main difference between a vegetative bud and a generative one is that stems and leaves of plants grow from the bud of the first type, and flowers or inflorescences grow from the bud of the second type.
It should be noted that there are also mixed, that is, vegetative-generative buds. As we mentioned above, in the structure of the generative buds of some plants there are also rudiments of stems and leaves.
Generative buds are usually larger than vegetative ones. Their apex is in many cases more rounded than that of vegetative rudiments.
Having determined what the difference is between a vegetative and generative bud, we will reflect the conclusions in the table.
Conducting minerals and water to the shoot is the next function of the root. The inner part of the root is represented by the central (axial) cylinder. The axial cylinder consists of a conducting system, which consists of xylem and phloem, surrounded by a ring of pericycle cells.
Some plants store nutrients in their roots. As a result of the accumulation of nutrients, the main root thickens and is called a root vegetable. Root vegetables consist of storage base tissue (turnips, parsley, beets). If lateral or adventitious roots thicken, they are called root tubers or root cones. Root tubers are formed in dahlia, potatoes, and sweet potatoes.
Roots can interact with fungi or microorganisms. This mutually beneficial interaction is called symbiosis. Cohabitation with fungal hyphae is called mycorrhiza. The plant receives water from the fungus with dissolved in it nutrients, and the fungus receives organic substances from the plant. In plants of the legume family, interaction of root nodules with nitrogen-fixing bacteria occurs. Bacteria convert nitrogen contained in the air into mineral form available to plants. And plants provide bacteria with habitat and additional nutrition.
Main article: Escape
Bud in plants
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).
Structure of plant buds
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 http://wiki-med.com
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).
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. Generative buds of many woody plants differ from vegetative ones in size and shape: they are larger and often rounded.
pastenia with wintering buds
vegetative buds of plants
Which apple tree buds are vegetative or generative?
, structure, classification of the kidney
kidneys that remain dormant for a long time are called
Questions for this article:
What is the function of the kidneys?
How do kidneys develop?
Structure and types of kidneys
1. The escape
knot, internode.
leaf axil.
axillary bud.
Closed node
Open node
Types of shoots
Elongated shoots have long internodes. During bud development, internodes develop rapidly. They perform the function of supporting or skeletal organs.
Short shoots have very close internodes.
Internodes hardly grow. U herbaceous plants the leaves sit very close, forming a rosette (primrose, plantain, dandelion). In woody forms, such shoots often bear flowers and fruits.
According to their functions, shoots are:
Vegetative
Generative (floriferous)
Main escape
Side shoots
Annual shoots
Elementary shoots
Escape structure
A
1 - apical bud;
2 - axillary bud;
3 - internode;
4 - leaf scar;
5 - node;
6
annual growth);
7
conductive bundles);
B
Structure and types of kidneys
Bud
Types of kidneys:
4 – rudimentary leaves.
Apical–(
Axillary buds
The bud consists of a stem with short internodes and rudimentary leaves or flowers. The top of the bud is covered with protective covering scales. The bud ensures long-term growth of the shoot and its branching, i.e.
formation of a shoot system.
Vegetative buds floral (generative) mixed,
Wintering
Open buds- naked, devoid of scales.
Stem
Stem
rounded, but also angular, three-, four- or multifaceted, ribbed, grooved, sometimes completely flat, flattened winged.
Branching of shoots
dichotomous, monopodial, sympodial.
At dichotomous
Dichotomous at lower plants ).
There are so-called isotomic anisotomic
At monopodial
Monopodial branching is the next stage in the evolution of shoot branching. In plants with a monopodial type of shoot structure, the apical bud is retained throughout the life of the shoot.
Monopodial branching is common among gymnosperms and is also found in many angiosperms (e.g., many palm species, as well as plants from Orchidaceae family–). Some of them have only one vegetative shoot(e.g. Phalaenopsis pleasant).
Monopodial plants
At sympodial
In plants with sympodial depending on the type of shoot structure, the apical bud, having completed development, dies or gives rise to a generative shoot.
After flowering, this shoot no longer grows, and a new one begins to develop at its base. The shoot structure of plants with a sympodial type of branching is more complex than that of plants with a monopodial type; sympodial branching is an evolutionarily more advanced type of branching. The word “sympodial” is derived from ancient Greek. συν- (“together”) and πούς (“leg”).
Plant buds
Sympodial .
Sympodial plants- a term most often used in describing plants of tropical and subtropical flora, as well as in popular scientific literature on indoor and greenhouse floriculture.
Such equal dichotomy (isotomy) represents the original type of dichotomous branching. It was characteristic of some rhyniophytes, but is also found in some modern lycophytes and pteridophytes, as well as in Psilotum.
As a result of the unequal growth of the two daughter branches, when one of the branches is somewhat ahead of the other, the equal dichotomy turns into an unequal dichotomy (anisotomy), very well expressed in the primitive extinct Devonian genus Horneophyton.
Types of shoot branching(according to L.I.
B – sympodial (birch);
Anatomy Classification of the kidneys
Kidneys are classified according to:
Location on the escape: apical(terminal) and lateral.
Kidney (botany)
A shoot of the first order (main shoot) develops from the apical ones, and shoots of the second, third, fourth, etc., develop from the lateral ones, that is side shoots.
2. Origin: there are axillary and extra-axillary. Axillaries are located in the leaf axil and are formed exogenously (in the form of tubercles).
Οʜᴎ there are single(located singly in the leaf axil) and group(several pieces each). Groups can be serial (several buds are located above each other) and collateral (located nearby).
Extra-axillary buds are located on the internodes and are formed on an already formed shoot endogenously (from the cambium, pericycle, phellogen, phloem parenchyma).
Broods These are the buds that grow into small plant, falling away from the mother and moving on to independent existence ( bryophyllum).
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81. Lilac branch:
A - general form, B – shoot tip, C – buds (longitudinal section):
1 – lateral bud, 2 – leaf scar, 3 – annual growth limit
4 – bud scales, 5 – rudimentary inflorescence, 6 – growth cone.
3. According to their significance in life, plants are classified into:
- dormant buds - formed at the end of the growing season and at rest tolerate unfavorable conditions (cold, heat), and with the onset favorable conditions give growth to the shoot;
- enrichment bud, which gives growth immediately after initiation, during the same growing season, forming enrichment shoots (increase the photosynthetic surface);
— dormant buds that, having become established, do not begin to grow for a number of years.
Such a bud annually forms a certain number of metamers; they are always located on the surface of the stem. When pruning and aging of the shoot system, they give growth and restore the shoot system of plants.
Based on their structural features, they are classified into:
- vegetative, consisting of a rudimentary stem and rudimentary leaves;
- vegetative-generative, in addition to the rudimentary stem and leaves, contain the rudiments of inflorescences and flowers;
- generative - contain the rudiments of inflorescences and flowers;
- closed, which are covered with dense kidney scales;
- open, without dense kidney scales.
Structure and types of kidneys
Types of macro- and microscopic structure of the stem
1. The escape- part of the stem that has grown in one growing season along with the leaves and buds located on it. This is an organ that arises from the apical meristem and is divided at an early stage of morphogenesis into specialized parts: stem, leaves, buds.
Its main function is photosynthesis.
Parts of the escape can also serve for vegetative propagation, accumulation of spare food, water.
The area of the stem at the level of leaf origin is called knot, and the section of the stem between two nodes is internode.
The angle between the leaf petiole and the stem is called leaf axil.
Forms above the node in the leaf axil axillary bud.
Closed node– a leaf or whorl of leaves completely surrounds the stem with its bases.
Open node– bears a leaf that does not completely cover the stem.
Types of shoots
In the case of clearly defined internodes, the shoot is called elongated.
If the nodes are close together and the internodes are almost invisible, then this is a shortened shoot (fruit, rosette).
According to the development of internodes, there are shoots.
Elongated shoots have long internodes.
During bud development, internodes develop rapidly. They perform the function of supporting or skeletal organs.
Short shoots have very close internodes. Internodes hardly grow. In herbaceous plants, the leaves sit very close, forming a rosette (primrose, plantain, dandelion). In woody forms, such shoots often bear flowers and fruits.
According to their functions, shoots are:
Vegetative– provide aerial nutrition to plants.
Generative (floriferous)- perform the function of reproduction, bearing flowers or fruits.
Main escape– the first shoot of a plant that develops from an embryonic shoot.
Side shoots– shoots of the second order, develop on the main shoot.
Annual shoots(growth) – grow from the buds in one growing season (once a year).
Elementary shoots– are formed in one growth cycle, but there are several of them per year.
Escape structure
A- horse chestnut shoot without leaves:
1 - apical bud;
2 - axillary bud;
3 - internode;
4 - leaf scar;
5 - node;
6 - place of attachment of the bud scales (border
annual growth);
7 - leaf traces (ends of torn
conductive bundles);
B- elongated annual shoot of aspen
Structure and types of kidneys
Bud- a shortened embryonic shoot, in a state of relative dormancy.
Types of kidneys: A – vegetative; 1 – embryonic shoot;
B – generative; 2 – kidney scales;
B – vegetative-generative; 3 – rudimentary flowers;
4 – rudimentary leaves.
Apical–( terminal) bud formed at the top of the shoot and causing the stem to grow in length.
Axillary buds–formed in the leaf axil and causing the development of lateral shoots.
The bud consists of a stem with short internodes and rudimentary leaves or flowers. The top of the bud is covered with protective covering scales. The bud ensures long-term growth of the shoot and its branching, i.e. formation of a shoot system.
Vegetative buds– form shoots with leaves; floral (generative)– form flowers or inflorescences; mixed,(vegetative - generative) buds - form leafy shoots with flowers.
Wintering(closed), or dormant buds have hard covering bud scales, which reduce evaporation from the surface of the internal parts of the buds, and also protect them from freezing, pecking by birds, etc.
Open buds- naked, devoid of scales.
Accessory (adventitious) buds are formed on any plant organs and do not differ in structure from others; they ensure active vegetative regeneration and reproduction of plants (raspberry, aspen, sow thistle, dandelion).
Stem
Stem– the main structural part of the shoot, consisting of nodes and internodes.
The stem has the following functions:
- conductive - ascending and descending currents of substances move between the roots and leaves in the stem.
- mechanical (supporting) - carries leaves, buds, flowers and fruits.
- assimilation - the green part of the stem is capable of performing the function of photosynthesis.
- storage of nutrients and water.
The stem usually has cylindrical shape and is characterized by radial symmetry in the arrangement of tissues.
However, in cross section it can be not only rounded, but also angular, three-, four- or multifaceted, ribbed, grooved, sometimes completely flat, flattened, or bearing protruding flat ribs - winged.
Types of stems by cross-sectional shape: 1 – rounded; 2 – flattened; 3 – triangular; 4 – tetrahedral; 5 – multifaceted; 6 – ribbed; 7 – grooved; 8, 9 – winged.
Types of stems by position in space: 1 – erect; 2 – rising; 3 – creeping; 4 – creeping; 5 – curly; 6 – climbing (clinging).
Branching of shoots
Branching - the process of formation of new shoots and their nature relative position on the stem, perennial branches and rhizome.
Since the shoot is an axial organ, it has an apical meristem, which ensures unlimited growth in length.
Such growth is accompanied by more or less regular branching of the shoot. In lower plants, as a result of branching, a branched thallus (thallus) appears, in higher plants, systems of shoots and roots are formed. Branching allows you to repeatedly increase the photosynthetic surface and provide the plant with organic substances.
U various plants Several types of branching are observed: dichotomous, monopodial, sympodial.
At dichotomous During branching, the growth cone splits in two (mosses).
Dichotomous branching is the most primitive type of branching, observed as in lower plants, and so do some higher plants(for example, at Bryophyta, Lycopodiophyta, some Pteridophyta).
With dichotomous branching, the growth cone is divided in two, the newly formed apexes are also divided in two, and so on.
There are so-called isotomic dichotomous branching (the resulting branches are equal in size) and anisotomic (in which the resulting branches are unequal)
At monopodial During branching, the apical bud functions throughout life, forming the main shoot (first-order axis), on which second-order axes develop in acropetal sequence, third-order axes on them, etc.
Monopodial branching is the next stage in the evolution of shoot branching. In plants with a monopodial type of shoot structure, the apical bud is retained throughout the life of the shoot. Monopodial branching is common among gymnosperms and is also found in many angiosperms (e.g., many palm species, as well as plants from Orchidaceae family–gastrochilus, phalaenopsis and others).
Some of them have a single vegetative shoot (for example, Phalaenopsis pleasant).
Monopodial plants- a term most often used in describing plants of tropical and subtropical flora, as well as in popular scientific literature on indoor and greenhouse floriculture.
Monopodial plants can vary significantly in appearance. Among them there are rosettes, with elongated shoots, and bush-like ones.
At sympodial During branching, one of the upper axillary buds forms a second-order axis, which grows in the same direction as the first-order axis, displacing its dying part to the side.
This division was first proposed by the German botanist Pfitzer at the end of the 19th century.
In plants with sympodial depending on the type of shoot structure, the apical bud, having completed development, dies or gives rise to a generative shoot. After flowering, this shoot no longer grows, and a new one begins to develop at its base. The shoot structure of plants with a sympodial type of branching is more complex than that of plants with a monopodial type; sympodial branching is an evolutionarily more advanced type of branching. The word “sympodial” is derived from ancient Greek.
συν- (“together”) and πούς (“leg”). Sympodial branching is typical for many angiosperms: For example, for lindens, willows and many orchids.
Sympodial plants- a term most often used in describing plants of tropical and subtropical flora, as well as in popular scientific literature on indoor and greenhouse floriculture.
In the first stages of evolution, the apical meristems of both branches of each fork grow at the same rate, which leads to the formation of identical or almost identical daughter branches.
Such equal dichotomy (isotomy) represents the original type of dichotomous branching.
Structure and types of kidneys
It was characteristic of some rhyniophytes, but is also found in some modern lycophytes and pteridophytes, as well as in Psilotum. As a result of the unequal growth of the two daughter branches, when one of the branches is somewhat ahead of the other, the equal dichotomy turns into an unequal dichotomy (anisotomy), very well expressed in the primitive extinct Devonian genus Horneophyton.
Types of shoot branching(according to L.I.
Lotova): A – dichotomous (moss);
B – monopodial (spruce, leaves removed);
B – sympodial (birch);
I-III – serial numbers of increments;
1 – apical bud; 2 – lateral buds; 3 – dead upper parts of shoots.
Escape structure
The organism of a flowering plant is a system of roots and shoots. Main function aboveground shoots - creation organic matter from carbon dioxide and water using solar energy. This process is called air feeding of plants.
A shoot is a complex organ consisting of a stem, leaves, and buds formed during one summer.
The main shoot is the shoot that develops from the bud of the seed embryo.
Lateral shoot is a shoot that appears from a lateral axillary bud, due to which the stem branches.
An elongated shoot is a shoot with elongated internodes.
Shortened shoot - a shoot with shortened internodes.
A vegetative shoot is a shoot that bears leaves and buds.
Generative shoot - a shoot bearing reproductive organs - flowers, then fruits and seeds.
Branching and tillering of shoots
Branching is the formation of lateral shoots from axillary buds.
A highly branched system of shoots is obtained when lateral shoots grow on one (“mother”) shoot, and on them, the next lateral shoots, and so on. In this way, as much air supply as possible is captured.
The branched crown of the tree creates a huge leaf surface.
Tillering is branching in which large side shoots grow from the lowest buds located near the surface of the earth or even underground. As a result of tillering, a bush is formed. Very dense perennial bushes are called turfs.
Types of shoot branching
During evolution, branching appeared in thallus (lower) plants; in these plants the growing points simply bifurcate.
This branching is called dichotomous; it is characteristic of pre-shoot forms - algae, lichens, liverworts and anthocerotic mosses, as well as thickets of horsetails and ferns.
With the appearance of developed shoots and buds, monopodial branching occurs, in which one apical bud retains its dominant position throughout the life of the plant.
Such shoots are orderly and the crowns are slender (cypress, spruce). But if the apical bud is damaged, this type of branching is not restored, and the tree loses its typical appearance(habit).
The most recent type of branching in terms of time of occurrence is sympodial, in which any nearby bud can develop into a shoot and replace the previous one.
Structure and types of kidneys
Trees and shrubs with this type of branching can easily be pruned, crown formed, and after a few years they grow new shoots without losing their habit (linden, apple, poplar).
A type of sympodial branching is false dichotomous, which is characteristic of shoots with opposite leaves and buds, so instead of the previous shoot, two grow at once (lilac, maple, chebushnik).
Kidney structure
A bud is a rudimentary, not yet developed shoot, at the top of which there is a growth cone.
Vegetative (leaf bud) - a bud consisting of a shortened stem with rudimentary leaves and a growth cone.
Generative (floral) bud is a bud represented by a shortened stem with the rudiments of a flower or inflorescence.
A flower bud containing 1 flower is called a bud.
Apical bud - a bud located at the top of the stem, covered with young leaf buds overlapping each other.
Due to the apical bud, the shoot grows in length. It has an inhibitory effect on the axillary buds; removing it leads to the activity of dormant buds. Inhibitory reactions are disrupted and the buds bloom.
At the top of the embryonic stem there is the growth part of the shoot - the growth cone. This is the apical part of the stem or root, consisting of educational tissue, the cells of which constantly divide through mitosis and give the organ an increase in length.
At the top of the stem, the growth cone is protected by bud scale-like leaves; it contains all the elements of the shoot - stem, leaves, buds, inflorescences, flowers. The root growth cone is protected by a root cap.
Lateral axillary bud is a bud that appears in the axil of a leaf, from which a lateral branching shoot is formed.
The axillary buds have the same structure as the apical one. The lateral branches, therefore, also grow from their apices, and on each lateral branch the terminal bud is also apical.
At the top of the shoot there is usually an apical bud, and in the axils of the leaves there are axillary buds.
In addition to apical and axillary buds, plants often form so-called accessory buds.
These buds do not have a certain regularity in location and arise from internal tissues. The source of their formation can be the pericycle, cambium, parenchyma of the medullary rays. Adventitious buds can form on stems, leaves, and even roots. However, in structure, these buds are no different from ordinary apical and axillary ones. They provide intensive vegetative regeneration and reproduction and are of great biological importance.
In particular, root shoot plants reproduce with the help of adventitious buds.
Dormant buds. Not all buds realize their ability to grow into a long or short annual shoot. Some buds do not develop into shoots for many years. At the same time, they remain alive, capable of certain conditions develop into a leafy or flowering shoot.
They seem to be sleeping, which is why they are called sleeping buds.
When the main trunk slows down its growth or is cut down, the dormant buds begin to grow, and leafy shoots grow from them. Thus, dormant buds are a very important reserve for the regrowth of shoots. And even without external damage, old trees can “rejuvenate” due to them.
Dormant buds, very characteristic of deciduous trees, shrubs and a number of perennial herbs.
These buds do not develop into normal shoots for many years; they often remain dormant throughout the life of the plant. Typically, dormant buds grow annually, exactly as much as the stem thickens, which is why they are not buried by growing tissues.
The stimulus for awakening dormant buds is usually the death of the trunk. When cutting down a birch, for example, stump growth is formed from such dormant buds. Dormant buds play a special role in the life of shrubs.
The shrub differs from a tree in its multi-stemmed nature. Typically, in shrubs the main mother stem does not function for long, several years.
When the growth of the main stem subsides, dormant buds awaken and daughter stems are formed from them, which outstrip the mother in growth. Thus, the shrub form itself arises as a result of the activity of dormant buds.
Mixed bud - a bud consisting of a shortened stem, rudimentary leaves and flowers.
Renewal bud - overwintering bud perennial plant, from which the shoot develops.
Vegetative propagation of plants
| Way | Drawing | Description | Example |
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Creeping shoots |
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Creeping shoots or tendrils, in the nodes of which small plants with leaves and roots develop |
Clover, cranberry, chlorophytum |
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Rhizome |
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With the help of horizontal rhizomes, plants quickly capture large area, sometimes several square meters. The older parts of the rhizomes gradually die and are destroyed, and individual branches separate and become independent. |
Lingonberries, blueberries, wheatgrass, lily of the valley |
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Tubers |
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When there are not enough tubers, you can propagate by parts of the tuber, bud eyes, sprouts and tops of tubers. |
Jerusalem artichoke, potatoes |
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Bulbs |
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From the lateral buds on the mother bulb, daughter buds are formed, which are easily separated. Each daughter bulb can produce a new plant. |
Bow, tulip |
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Leaf cuttings |
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The leaves are planted in wet sand, and adventitious buds and adventitious roots develop on them |
Violet, sansevieria |
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By layering |
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In spring, bend the young shoot so that its middle part touches the ground and the top is directed upward. On the lower part of the shoot under the bud, you need to cut the bark, pin the shoot to the soil at the cut site and cover it with damp soil. By autumn, adventitious roots are formed. |
Currants, gooseberries, viburnum, apple trees |
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Shoot cuttings |
A cut branch with 3-4 leaves is placed in water, or planted in wet sand and covered to create favorable conditions. Adventitious roots form on the lower part of the cutting. |
Tradescantia, willow, poplar, currant |
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Root cuttings |
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A root cutting is a piece of root 15-20 cm long. If you cut off a piece of dandelion root with a shovel, adventitious buds will form on it in the summer, from which new plants will form |
Raspberry, rosehip, dandelion |
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Root suckers |
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Some plants are able to form buds on their roots |
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Grafting with cuttings |
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First, annual seedlings called wildflowers are grown from seeds. They serve as a rootstock. WITH cultivated plant cuttings are cut - this is a scion. Then the stem parts of the scion and rootstock are connected, trying to connect their cambium. This way the tissues grow together more easily. |
Fruit trees and shrubs |
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Kidney grafting |
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WITH fruit tree cut off an annual shoot. Remove the leaves, leaving the petiole. Using a knife, an incision is made in the bark in the shape of the letter T. A developed bud from a cultivated plant, 2-3 cm long, is inserted. The grafting site is tightly tied. |
Fruit trees and shrubs |
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Tissue culture |
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Growing a plant from educational tissue cells placed in a special nutrient medium. Plant |
Orchid, carnation, gerbera, ginseng, potato |
Modifications of underground shoots
Rhizome is an underground shoot that performs the functions of deposition of reserve substances, renewal, and sometimes vegetative propagation.
The rhizome has no leaves, but has a well-defined metameric structure; nodes are distinguished either by leaf scars and remains of dry leaves, or by leaf scars and remains of dry leaves, or by living scale-like leaves and the location of axillary buds. Adventitious roots can form on the rhizome. From the buds of the rhizome its lateral branches grow and aboveground shoots.
Rhizomes are characteristic mainly of herbaceous perennials- hoofweed, violet, lily of the valley, wheatgrass, strawberry, etc., but they also occur in shrubs and shrubs.
The lifespan of rhizomes ranges from two or three to several decades.
Tubers are thickened, fleshy parts of the stem, consisting of one or more internodes. There are above-ground and underground.
Aboveground - thickening of the main stem and side shoots. Often have leaves. Aboveground tubers are a reservoir of reserve nutrients and serve for vegetative propagation; they may contain metamorphosed axillary buds with leaf buds, which fall off and also serve for vegetative propagation.
Underground tubers - thickening of the subcotyledon or underground shoots.
On underground tubers, the leaves are reduced to scales that fall off. In the axils of the leaves there are buds - eyes. Underground tubers usually develop on stolons - daughter shoots - from buds located at the base of the main shoot, look like very thin white stems bearing small colorless scale-like leaves, grow horizontally.
Tubers develop from the apical buds of stolons.
A bulb is an underground, less often above-ground, shoot with a very short thickened stem (bottom) and scaly, fleshy, succulent leaves that store water and nutrients, mainly sugar. Aboveground shoots grow from the apical and axillary buds of the bulbs, and adventitious roots form on the bottom.
Depending on the placement of leaves, bulbs are classified as scaly (onion), imbricated (lily) and compound or complex (garlic). In the axil of some scales of the bulb there are buds from which they develop daughter bulbs- kids. Bulbs help the plant survive in unfavorable conditions and are an organ of vegetative propagation.
Corms - outwardly similar to bulbs, but their leaves do not serve as storage organs, they are dry, filmy, often the remains of dead sheaths green leaves.
The storage organ is the stem part of the corm; it is thickened.
Aboveground stolons (lashes) are short-lived creeping shoots used for vegetative propagation.
Found in many plants (drupes, bentgrass, strawberries). They usually lack developed green leaves, their stems are thin, fragile, with very long internodes. The apical bud of the stolon, bending upward, produces a rosette of leaves that easily takes root. After the new plant takes root, the stolons are destroyed. Popular name these aboveground stolons are whiskers.
Spines are shortened shoots with limited growth. In some plants, they form in the axils of the leaves and correspond to the side shoots (hawthorn) or are formed on the trunks from dormant buds (locust locust).
Characteristic for plants in hot and dry growing areas. Perform a protective function.
Succulent shoots are above-ground shoots adapted to store water. Typically, the formation of a succulent shoot is associated with the loss or metamorphosis (transformation into spines) of leaves. The succulent stem performs two functions - assimilation and water storage. Characteristic of plants living in conditions long-term lack moisture.
Stem succulents are most represented in the cactus and euphorbia family.
Main article: Escape
Bud in plants- this is a rudimentary shoot. A vegetative bud 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.
Types of plant buds
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 the evaporation of water from the surface of the internal parts of the buds, and also protect the buds 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.
Tree structure. From cells to roots
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 are of great importance for restoring the crown when it is damaged by spring frosts and during decorative pruning of 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.
Structure of plant buds
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 http://wiki-med.com
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.
On this page there is material on the following topics:
plant bud biology external and internal structure
axillary and accessory buds
internal structure and external buds of poplar
plant bud functions
bud structure in plants
Questions for this article:
What are kidneys?
What is the function of the kidneys?
How do generative buds differ from vegetative ones?
How do kidneys develop?
What are dormant buds and what function do they perform?
Material from the site http://Wiki-Med.com
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 longitudinal section buds, 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 closest nodes of the same shoot are called internodes.
2. What types of leaf arrangement do you know?
Plants exhibit 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 average daily temperature sets 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 in woody plants is amazingly high: 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, a sooty fungus settles here, 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 or 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 begins to develop side shoots. If you cut off the top of a side shoot, it will also stop growing in length and begin to branch.
Answer from Alina Nosova[newbie]
1) vegeto - I revive, excite,
vegetativus - growing,
Answer from Suck through[guru]
They differ from each other in that (if you don’t delve into microbiology) that vegetative buds produce only leaves, while generative buds, in addition to leaves, also have flowers, thanks to which the tree bears fruit. The buds are formed even before the leaves fall in the leaf axil. Therefore, it is possible to judge whether there will be a harvest for next year this year. External signs they differ in that the vegetative bud is cone-shaped and slightly elongated, while the generative bud does not have a sharp cone at the apex, it is smoother and rounded. Best time to determine the future harvest it is spring next year, when the average daily temperature is about +5 degrees. The process of bud swelling is underway. It becomes larger and then you can clearly see everything that I talked about earlier.
P.S. when pruning in spring, do not be afraid to cut out branches with generative buds, this will not harm the tree and will not reduce the yield (if pruned correctly)
Answer from Neurologist[newbie]
Vegetative bud: Formed in the axil or at the tip of the shoot. It may immediately begin to develop, or it may dry out. A bud is a shortened shoot; when a bud germinates, it produces shoots of varying lengths.
Generative bud: The buds contain the primordia of flowers. They are more rounded and dense. From the generative bud, only a portion of the stem and leaves develop.
Answer from Lumbago[newbie]
vegetarian
Answer from Just Do it[newbie]
Well, in general, vegetative - only with embryonic shoot and generative ones - with a rudimentary shoot and flower primordia