Mossy plants, their characteristics. Kukushkin flax reproduces by seeds. Kukushkin flax: structure and reproduction Kukushkin flax life cycle diagram

Kukushkin flax is a genus of moss. Usually, when considering the structure of cuckoo flax, one of its species is considered (common cuckoo flax), which is widespread in Russia. This plant grows in places with high humidity and needs good lighting. Kukushkin flax forms a dense cover on the ground, which prevents the growth of other plants and the evaporation of moisture. As a result, it can lead to waterlogging of soils.

In appearance, cuckoo flax is a herbaceous plant about 20 cm high. The stem usually does not branch and has a greenish-brown tint. There are many narrowed thin leaves on the stem. You can see the vein on them. Cuckoo flax is attached to the soil using rhizoids (similar to roots, since they do not have tissues characteristic of roots).
Kukushkin ordinary flax

The stem serves for support and transport of substances. Cuckoo flax has primitive conductive tissues. So water with minerals flows through some cells, and organic substances through others.

The leaves contain rows of cells, the main function of which is photosynthesis, i.e. the synthesis of organic substances. However, apparently leaves can also absorb water.
Rhizoids not only attach the plant to the soil, but also absorb water with minerals dissolved in it.

Kukushkin flax reproduces by spores. When a spore lands on moist soil, it germinates, forming a so-called seedling. It looks like a branching thread. The seedling produces buds from which cuckoo flax plants grow.

Kukushkin flax is a dioecious plant. This means that it has male and female plants. At the top of the stems of male plants, so-called antheridia are formed. Sperm mature in them. Archegonia are formed on female plants. An egg cell matures in each archegonia.

During rains or floods, sperm swim towards the eggs. Fertilization and formation of a zygote occurs. Water plays an important role in the life of mosses. Only thanks to it is sexual reproduction possible. Thus, in evolutionary development, mosses not only did not go very far from algae in structure, but also in their way of life.

Spores ripen in the sporophyte capsule. When the cap falls off, the spores scatter. Once in favorable conditions, they give rise to a new seedling.

1. General characteristics of green mosses.

In the life cycle of green mosses, like all bryophytes, the haploid generation predominates - the gametophyte, the sporophyte in the form of a capsule, which develops on the gametophyte. The largest genus of green mosses is cuckoo flax. Mosses of this genus are perennial plants. They usually grow in swampy forests and along the edges of swamps, forming dense, dense turf.

2. External structure of cuckoo flax moss.

The stem of cuckoo flax is erect, usually unbranched (30-40 cm), the leaves are linear-subulate. The leaf has a midrib. Cuckoo flax has no roots. They are replaced by thread-like outgrowths - multicellular rhizoids, which are located on the lower part of the stem. They absorb water from the soil and also serve for attachment.

3. Reproduction and development of cuckoo flax moss.

Kukushkin flax is a dioecious plant. Female genital organs (archegonia) and male genital organs (anteridia) develop on different plants. Oocytes are formed in archegonia, spermatozoa are formed in anthridium. Male plants can always be distinguished by the presence of larger yellow-brown leaves that surround the male genital organs - antheridia. There are no such leaves on female specimens. After the fertilization of eggs by sperm, which enter the female genital organs through drops of water, a sporophyte is formed from the zygote - a box on a long stalk (promotes the spread of spores over a greater distance). The box consists of an urn and a lid, 38 covered with a cap on top. The urn contains a sporangium with spores. When the spores mature, in dry weather the cap, followed by the cap, falls off. The thin leg sways even from the slightest breath of wind, and small and light spores spill out. Material from the site

Development cycle: spores (haploid; during their formation, reduction division occurs) -> spore germination in moist soil -> filamentous pregrowth (proto-nema) -> buds are formed on the protonema, and from them leaf-stem plants (haploid gametophytes) .

4. Origin of the name "cuckoo flax".

The slender brown stems of cuckoo flax are dotted with small dark green leaves and look slightly like a smaller flax plant. Hence the last part of the name - flax. The capsules that appear on female plants look like sitting on the "pole" cuckoo

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On this page there is material on the following topics:

• micropreparation of sporangia of zozuline lyon
• about the general features of the structure of mosses
• cuckoo tears short essay
• sexual reproduction of cuckoo flax
• cuckoo flax propagation

Kukushkin flax belongs to the bryophyte plants of the green moss family. At the moment, there are more than 100 varieties of this plant family, which are distributed throughout the globe. Most often, cuckoo flax can be seen in our forests, swamps, mountains, tundra, as well as in the northern part of the country. In addition, certain species of this plant family take an active part in waterlogging and peat formation of the soil.

In our country, as well as other CIS countries, the cultivation of cuckoo flax became known several centuries ago. Already today, about 10 varieties of cuckoo flax grow on the territory of our state. The largest amount of this plant is concentrated in the forests of the northern and central parts. The most widespread among this family of green mosses is rightfully considered to be common cuckoo flax, or as it is also popularly called - polytrichum vulgaris. It is these plants that represent forests in the taiga, swamps and other types of northern areas.

Growing cuckoo flax
The cultivation of cuckoo flax began in ancient times, when people began to insulate their houses and roofs with bast plant species. And even despite the fact that cuckoo flax is not a direct relative of the bast family (flax, jute, hemp), nevertheless, it has good hygroscopic properties, due to which coatings from such a plant can not only perfectly absorb moisture, but also release her at the right time. It was thanks to cuckoo flax that in old buildings of those times not only ventilation of the grooves was ensured, but also the destruction of the house itself was prevented.

Speaking about the structure of this plant, first of all, I would like to note that cuckoo flax belongs to the perennial leafy family of green mosses. As a rule, growing cuckoo flax at home allows you to get a fairly large plant with pronounced rhizoids in the lower part of the stems. The primary stem of cuckoo flax under normal conditions develops without leaves, but the secondary stem can be either simple or branched. The average length of the secondary stem, as a rule, reaches 30-40 cm. All stems along their entire length are densely covered with leaves, which have assimilation plates in the upper part. The leaves, which are located at the bottom of the stem, are presented in the form of scales.

The inner part of the stem is represented by both a primitive conducting system, which ensures the movement of water and other useful substances along the plant stem, and individual cells that perform the function of transporting water.
Cuckoo flax reproduces both asexually and sexually. As for the asexual process of reproduction, it can be noted that the gametophyte of a plant is a special green shoot with leaves. As a result, the plant produces many spores, from which, under normal conditions for growing cuckoo flax, a shoot in the form of a box (sporangium) develops. The structure of this capsule differs from similar spore capsules of other plants of this family, since in the upper part it is closed with a cap and in appearance resembles a linen buckle. The box itself resembles a cuckoo. This is what determines the name of this plant - cuckoo flax.

With the modern pace of life, constant pollution of the external environment, as well as the appalling state of the environment, growing flax is simply necessary. Initially, this is due to the fact that this leads to the accumulation of moisture and also promotes the formation of peat.

Kukushkin flax is a plant that in the territory Russian Federation most common in the forests of the northern and middle zones. Favorable conditions for it are observed in taiga swampy forests, swamps and wet meadows. The plant belongs to the genus of leaf-stemmed mosses; more than a hundred of its varieties are found on the planet. Kukushkin flax, which forms cushion-shaped tufts, is often found in the tundra and mountainous areas. Polytrichum vulgaris (the second name of the plant) is the most widespread in the CIS countries.

Great importance of the sun

Kukushkin flax loves light very much. That is why in dark spruce forests, even if the soil there is damp and fertile, it will be limited in growth and development. With enough sunlight, the plant rapidly stretches, actively capturing new areas and covering the soil with a dense carpet. The ground under cuckoo flax dries out much more slowly, which is why its growth gradually leads to swamping of the area.

Description

Cuckoo flax moss is distinguished by rather tall stems (their length is 10-15 centimeters, but forty-centimeter plants are also found). The conductive system ensures the movement of water and nutrients along the stem.

origin of name

The described plant has straight stems of a brownish color. They bear small dark green leaves that resemble flax in miniature. But the boxes that appear on female plants evoke associations with a cuckoo perched on a kind of pole.

The structure of cuckoo flax

The plant in question is classified as a leafy perennial moss. Its size is large; in the lower part of the stem there are rhizoids - primitive analogues of roots. There are no leaves on the primary horizontal stem. The secondary stem can be either simple or branched. It is erect, the average length is within fifteen centimeters. Each leaf has a main large vein. Kukushkin flax, the structure of which is quite simple, has scale-like lower leaves.

Functions of the stem

The main role of this part of the plant is supporting. The conductive capacity of the stem is no less important. It acts as a link between the leaves and the root system. The stem also performs some secondary functions. Among them is maintaining the supply of nutrients.

Reproduction and development

The plant reproduces in the following ways: sexually (gametes) and asexually (spores, shoots). They alternate.

How exactly does the cuckoo flax plant reproduce? The spores that the plant produces are in a sporangium (box) on a stalk. After ripening, they spill out of this natural storage. Under favorable conditions, spores form a multicellular thread, and from it, in turn, several gametophytes appear (this happens by budding). A gametophyte is a green perennial shoot that has leaves and rhizoids (root-like formations). The latter take salts and iodine from the soil. Leaf cells provide the synthesis of all other necessary substances. Based on this, it can be argued that the gametophyte is an independent organism.

After some time, the gametophyte stops growing. Then the cuckoo flax begins to reproduce. In the center of the rosette of leaves (location - at the top of the stem) male and female genital organs develop. The first are represented by antheridia (the name comes from the Greek word “anteros”, which means “blooming”), in which mobile gametes - sperm, as well as archegonia - female genital organs, which are responsible for the formation of a stationary female gamete - the egg, undergo a development cycle.

Male plants are characterized by the presence of larger leaves, colored in. Female specimens do not have such leaves.

When a rainy period or high water occurs, sperm (male cells) are able to swim to the egg. As a result, they merge. Upon completion of the fertilization process, a zygote appears (this word comes from the Greek “zygotos”, which translates as “joined”). This is the first stage of embryo development. The next year, from the fertilized zygote, a capsule (sporogon) develops, located on a rather leafless plant. Subsequently, the capsule becomes the site for the development of spores. This natural repository is very fragile. It sways even in a light breeze. After the cap falls off and the spores fall out, the germination of a green branched thread - a pre-spring - is observed. Note that for a successful result it is necessary that the spores enter an environment favorable to them, in which case the cuckoo flax will reproduce.

On the pre-bud, buds are formed, from which female and male specimens of the plant emerge. Thus, it can be seen that the life cycle of moss development includes a sequential alternation of asexual and sexual generations. During evolution, this feature was developed in many plants, including cuckoo flax.

Propagating this vegetatively makes it easy to get a thick green carpet in your garden. It is enough just to place a small piece of moss on a damp area. However, one should take into account the ability of this plant to swamp its habitat.

Use for various purposes

If you remove the leaves from the cuckoo flax, you can get flexible, hard threads formed by the central stems. Our ancestors used this natural material to make brushes and brooms. Once soaked and combed, the stems made an excellent base for mats, rugs, baskets and blackout curtains. It is noteworthy that during excavations of an early Roman fort in England, the remains of baskets made from cuckoo flax were found. The pieces date back to 86 AD.

Previously, cuckoo flax was widely used in the manufacture of cloaks for warriors and travelers. The resulting garments were particularly durable. In addition, they had decorative value.

Healers advise using this type of moss to activate the digestive system, eliminate stomach colic and dissolve kidney and gallstones.

Kukushkin flax, the structure of which allows it to be used in gardening for decorative purposes, has a positive effect on the soil. So, this plant is capable of normalizing soil acidity in a maximum of two seasons. After this, any garden plants can be successfully grown on the restored soil. Dead parts of moss will serve as an excellent fertilizer.

The most unusual use of cuckoo flax is as malt in the production of whiskey.

Natural insulation

Kukushkin flax can effectively protect a structure from the penetration of cold and moisture. The fact that moss does not rot is greatly appreciated. Its placement between the logs of the log house allows for moss to be used fresh for these purposes. Before laying natural insulation, it must be thoroughly cleaned of twigs, sticks, cones, grass and other inclusions.

Sphagnum moss

This plant belongs to the genus of white (peat) mosses. 320 of its species have been identified. Sphagnum moss is predominantly represented by bog mosses, which form dense clumps that form either large cushions or thick carpets in sphagnum bogs. But in humid forests, sphagnum is much less common. This plant resembles Kukushkin flax with its erect stem, reaching ten to twenty centimeters in height. The leaves of sphagnum are single-layered and placed on fascicle-shaped branches. The leaves contain many aquifer cells with pores that actively absorb water. This fact determines the plant’s greater moisture capacity. In areas where these mosses appear, raised bogs quickly develop.

Every year the stems in the lower part of the plant die off. They form peat. Further growth of the stem is ensured by the apical branches.

Note that sphagnum plays an important role in the formation and existence of swamps. As mentioned above, dead areas of moss form peat deposits. Peat formation is possible due to stagnant waterlogging, the provision of an acidic environment by mosses and the lack of oxygen. Under these conditions, rotting processes do not occur and sphagnum does not decompose. Peat is a valuable product from which wax, ammonia, paraffin, alcohol, etc. are obtained. It is widely used in medical practice and in construction. Moss acts as a biofuel and an effective fertilizer.

How is sphagnum useful?

Many recipes of traditional and official medicine include this component. And all because sphagnum moss is an excellent antiseptic and reliable. It helps heal purulent wounds due to its ability to absorb a large number of moisture. In this indicator, sphagnum is superior to the best varieties of absorbent wool. This moss is capable of producing a bactericidal effect due to the presence of sphagnol - a special phenol-like substance that inhibits the development and vital activity of E. coli, Vibrio cholerae, Staphylococcus aureus, Salmonella and some other pathogenic microorganisms.

Flower growers actively use sphagnum moss to grow indoor plants. It is a component of the substrate, a mulch layer or performs drainage functions. Moss is not rich in nutrients, but it gives the soil the required looseness. The excellent hygroscopicity of sphagnum explains its ability to evenly distribute moisture. The presence of sphagnol determines the bactericidal properties of the described type of moss, which allows you to effectively care for the roots of the main plant, preventing the development of diseases and decay.

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Scheme 11. Alternation of generations among representatives of the Bryophytes department

Table 13. Department Bryophytes

(Marschantia L.) - a genus of liver moss from the family. Marchantiaceae; This is a perennial plant that looks like a green lobed leaf (layer) spreading along the surface of the ground. On the upper, sometimes rhombically mottled surface, there are calyxes with brood buds. Antheridia are located on special processes, sometimes consisting of a scutellum and a thin stalk, sometimes of a single sessile scutellum. Archegonia are collected on other shoots that look like an asterisk on a stalk. The capsule opens with eight backward-curved teeth; perianthium 4-5 lobed. In addition to spores, springs (elaters) also develop in the capsule. There are about 25 species of M., scattered throughout the earth, usually in damp, damp places. The most common species is M. polymorpha L. The fleshy lobed thallus of this plant is up to 10 cm long and up to 3 cm wide; in the middle, along the thallus, starting from the front notch, where growth is concentrated, a wide, indistinct vein runs. The upper surface is dotted with diamonds, representing the outline of the so-called internal ones. air cavities; in the cavities there is assimilation tissue, in the form of green threads extending from the bottom of the cavity; The cavity opens with a hole located in the middle of the rhombic section of the upper surface of the layer. Scaly appendages and root hairs extend from the underside. Men's - with a notched edge, scutes on a leg; antheridia embedded in the upper surface of the scutellum.

The development cycle of green moss (using the example of cuckoo flax) - structural and logical diagram

Female stars are on other specimens (M. polymorpha is a dioecious plant). Archegonia are placed between the rays of the asterisk, on the underside of them, several at a time. M. polymorpha grows in damp places, along the banks of streams, etc.; Previously, it was used in medicine (herba hepaticae fontinalis s lichenis stelati) against liver diseases, etc.

Bryophytes

Bryophytes, or mosses, are a division of higher plants that includes more than 100 families, 700 genera and about 10 thousand species. These ancient plants have been known since the Carboniferous period. According to scientists, mosses are a separate branch in the evolution of higher plants, and green algae are considered their ancestors.

Question No. 38

Bryophytes are divided into three broad classes: phyllophytes, anthocerotes and liver mosses. The most numerous group is the phyllophytes, or true mosses. These are the well-known cuckoo flax and sphagnum.

Mosses are distributed throughout our planet, including Antarctica. There are 1,500 species found in the CIS countries. Bryophytes spread everywhere, with the exception of seas, soils with a high salt content and places subject to intense erosion. They form massive clusters in shady areas, often near water bodies, but can also develop well in open, dry places. With increased growth of mosses, soils become waterlogged and the quality of agricultural land decreases. In swampy areas, these plants form the bulk of peat deposits.

The structure of bryophytes

The vast majority of mosses are perennial terrestrial (less often freshwater) plants. Their characteristic feature is group growth forms (pillows, turf, curtains). The vast majority of mosses are small plants only a few centimeters high; rare aquatic forms reach a length of up to 30 cm. Bryophytes lack roots, a conducting system, and flowers, like angiosperms. Mechanical, water-conducting and assimilation tissue are only partially separated. The tissues of all plants in this department contain a green photosynthetic pigment - chlorophyll, although the color of the leaves of different species can vary from dark brown to light green. Conventionally, the organism of a moss specimen is divided into a stem and leaves; some species look like flat leaf-shaped plates - thalli. Rhizoids, analogues of the roots of higher plants, are used for attachment to the soil or other substrate.

Reproduction of bryophytes

Reproduction occurs asexually, vegetatively and sexually. Therefore, these plants are capable of rapid dispersal. During vegetative propagation, young individuals develop from parts of the mother plant (leaves, branches, special buds, nodules, brood bodies). This is how cloned plants grow and can cover large areas.

Both sexual and asexual generations of mosses develop on the same plant.

The haploid sexual generation predominates in the life cycle of bryophytes. A gametophyte is a perennial plant with leaf-like and root-like (rhizoids) outgrowths. The organs of sexual reproduction are antheridia and archegonia. Antheridia produce biflagellate spermatozoa that are capable of moving to the egg from archegonia exclusively in an aquatic environment. When germ cells fuse, a diploid sporophyte is formed.

Asexual reproduction occurs through the formation of spores. The sporophyte is short-lived, is located on the gametophyte and consists of three parts: the sporangium (box) with spores, the stalk to which the box is attached, and the sole - the place of attachment to the gametophyte. The close connection between the sporophyte and the gametophyte explains the fact of group growth forms in mosses.

The meaning of bryophytes

In nature, bryophytes are the first to colonize uninhabited substrate and are dominant in biocenoses, where they cover the soil with a continuous carpet (tundra). Mosses play an important role in regulating the water balance of landscapes due to their ability to absorb and retain huge amounts of water.

In human agriculture, mosses cause waterlogging and deteriorate the quality of agricultural land. By growing, they can prevent soil erosion by removing moisture from the surface into groundwater. A number of sphagnum mosses are used in medicine as dressings. Bryophytes are involved in the creation of mineral deposits - peat.

The development cycle of leafy moss using the example of cuckoo flax moss

This is the most common representative of green mosses. Grows in wet and humid forests, on hummocks of peat bogs. It forms dense tufts of erect “stems” about 40 cm high, covered with narrow linear-lanceolate “leaves”, which consist of several layers of cells. In the middle of the “leaf”, like a central vein, conducting elongated and thick-walled mechanical cells are formed. On the upper surface of the “leaf” a green fringe of short chlorophyll-bearing filaments is formed. This is photosynthetic tissue. Multicellular rhizoids develop near the base of the “stem”.

The organs of sexual reproduction are located at the tops of the “stems” of different plants, which usually grow nearby. Male specimens show large reddish (or yellowish) “leaves” forming a rosette around the antheridia. Antheridium is a sac on a short stalk in which sperm develop. Archegonia are collected in a group and form the female reproductive bud, or female “flower”. The “leaves” surrounding the archegonia are no different from the stem leaves. Archegonia are flask-shaped structures with a long narrow neck and a swollen abdomen. An egg develops in them.

After fertilization of the archegonial egg by a sperm, which occurs in the presence of water, the sporophyte begins to develop. The sporophyte consists of three parts: the foot, the leg and the capsule in which the spores are formed. The stalk and capsule of the sporophyte are called sporogon. The sporogonous capsule is covered with a cap on top, under which the lid of the capsule is located. Inside there is a central rod - a column to which the spore sac is attached (spores develop in it). The capsule has a special device for dispersing spores - a peristome. These are denticles located along the edge of the box, between which there are pores. The denticles are capable of hygroscopic movements, as a result of which in dry weather they open pores through which spores spill out. On the ground, the spore germinates, forming a protonema, or pregrowth, in the form of a green branched thread. Buds appear on the protonema, from which the gametophyte develops over time.” Kukushkin flax is a perennial plant.

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The development of bryophytes does not differ from other higher plants and represents an alternation of haploid and diploid phases of development. The predominant generation is gametophyte. It develops from a spore, the nucleus of which has a haploid set of chromosomes, so all gametophyte cells are also haploid. Initially, a protonema develops from the spore, which has the appearance of a branching filamentous algae or plate. The spore does not contain any reserve of nutrients, so the young gametophyte must synthesize them independently through photosynthesis. The presence of chlorenchyma necessary for this determines the green color of the gametophyte. The further development of the plant from the protonema depends on its systematic position.

U liver mosses repeated division of the apical cell in three planes gives rise to lamellar structures on which the reproductive organs will subsequently develop, and therefore they are called gametophores (). More complex gametophyte formation occurs in deciduous mosses. Their gametophores look like leafy shoots, and they develop from buds that form on the protonema.

On gametophores genital organs are formed - female archegonia and male antheridia. Most often, organs of only one sex develop on one plant - dioecious mosses, but dioecy often occurs (when both female and male genital organs are formed on one individual). Finally, in some forms polyhomy is noted. In this case, both unisexual and bisexual gametophores are formed on one plant. Archegonia and antheridia are usually located in groups and are typically surrounded by various types of protective formations. Most often, with the help of stands, they rise above the surface of the gametophyte, but often sink into its depths.

Antheridia They are oval bodies surrounded by a thin single-layer membrane. They are filled with spermatogenic cells, which, during mitotic division, give rise to two motile spermatozoa equipped with two flagella. Let us recall that gametophyte cells are initially haploid, therefore sex cells are formed not as a result of meiosis, as is usually the case in diploid organisms, but through mitosis.

Archegonium is more complex and usually consists of a bottle-shaped structure. In its thickened part, called the abdomen, there is a large egg, which is also formed as a result of mitosis. Inside the narrowed neck, cervical cells are located in one row, one of which, the abdominal cervical cell, is located above the egg.

Despite the fact that bryophytes are terrestrial plants, fertilization in them is possible only in the presence of drip-liquid water. Through the neck, sperm penetrate into the abdomen of the archegonium and fertilize the egg located there. As a result, a diploid zygote is formed, which, after a certain period of dormancy, gives rise to the diploid generation - the sporophyte.

The sporophyte of bryophytes is called sporogon and among all higher plants it has the simplest structure. In a typical case, it is a capsule, which is a sporangium, which passes into the body of the gametophyte through a stalk. The overgrown and modified upper wall of the archegonium covers the capsule and is called a cap, or calyptra. Not having a green color, the sporogon of modern bryophytes does not contain chlorophyll and is not able to independently supply itself organic compounds. Therefore, the sporogon receives all the substances necessary for development from the gametophyte through the lower expanded part of the leg, the haustorium, penetrating into its tissues. Inside the capsule, numerous spore mother cells divide by meiosis and give rise to tetrads of haploid spores, through which asexual reproduction of bryophytes occurs (208). In liver mosses, in the capsule among the spores there are special cells that are modified into springs - elaters. They are hygroscopic, i.e. the ability to absorb water vapor when the humidity of the atmospheric air increases. In this case, the elaters unwind, and when the humidity drops, they curl again, mixing and loosening the mass of spores, which helps push them out of the box after it opens with several flaps.

Deciduous mosses do not have elaters. The problem of uniform dispersion of spores is solved thanks to a special structure - cirrus. It consists of many small denticles located in one or several rows around the expanded part of the box (urn). Like elaters, peristome denticles are hygroscopic. In humid weather, they become saturated with water, which leads to their deformation and blocking of the holes in the box. In this case, the spores are not thrown out, but water cannot get into the box. In dry weather the reverse process occurs.

Cuckoo flax moss: structure and reproduction of the plant

The teeth of the peristome dry out and bend outward, thereby opening holes in the capsule, and the spores falling out of it are picked up by the wind and transported to distances, often significantly distant from the mother plant. The vast majority of spores die when exposed to an unfavorable environment, but so many spores are produced that some of them necessarily end up in moist soil and there protonema sprouts from them, giving rise to a young gametophyte

Along with the development cycle described above with the change of gametophytic and sporophytic generations, vegetative reproduction is also widespread in bryophytes. In liverworts, brood bodies and brood baskets are formed, and in leafy mosses, secondary protonemas can be formed from almost all gametophyte structures.

The importance of bryophytes in nature quite limited and mainly consists of soil formation. These plants themselves do not need a nutrient substrate to the same extent as other higher plants, since they do not have roots and are able to absorb the substances they need over the entire surface of the body. Therefore, bryophytes are among the first (along with lichens) to inhabit bare rocks and other places hitherto devoid of vegetation, gradually covering them with a continuous carpet. Bryophytes are lowly vulnerable to biotic factors because they are very weakly affected by microorganisms, are extremely reluctant to be eaten by insects, birds and herbivores (most often they simply do not touch them at all) and, despite their slow growth (which is only a few millimeters per year), As a result, they produced colossal deposits of peat, which is formed due to incomplete rotting of the gradually dying lower parts of plants. In addition, bryophytes are involved in the regulation of water balance, as they retain water and transfer it to the ground state. This often leads to waterlogging of soils and, accordingly, a deterioration in their productivity. It should also be noted that bryophytes have the ability to accumulate salts of heavy metals and radionuclides in their bodies.

The use of bryophytes in human economic activity is more significant and, above all, is based on the exploitation of peat.

Russia ranks first in the world in terms of peat deposits. In some deposits, the thickness of the peat layer can be quite significant and reach several meters (up to ten). Most often, peat is used in agriculture as an organic fertilizer and as a mulching substrate to improve the aeration quality of heavy clay soils, making their structure lighter. Peat is used as fuel. In addition, peat is actively used in the construction industry due to its high thermal insulation properties. Bryophytes are less widely used in medicine. In particular, sphagnum has bactericidal properties and absorbs well, which made it possible to widely use it during the Second World War (the cheapness and abundance of moss was especially important during that period given the widespread shortage of medicines).

Kukushkin flax, or polytrichum, is a moss that prefers areas with excess moisture. This type of moss grows in well-lit wetlands. In our country, it is most often found in the north or center.

Structure

The dark green stem can grow from 5 to 50 cm in height. Its leaves are linear-subulate, have no petioles and are pointed. At the bottom of the stem there are rhizoids - this is a formation in the form of threads. They attach to the substrate and conduct micronutrients into the moss cells.

Source: Depositphotos

Inside the stem there is a conducting system that delivers water and dissolved nutrients to all the cells of the plant.

The main stem grows perpendicular to the ground and has no leaves. The secondary stem is branched and has leaves. Those leaves that are located next to the rhizoids develop in the form of scales.

The leaves of the plant are straight. When they are dry, they adhere to the stem, and when wet, they bend away from it. Also on the upper surface of the leaves there are vertical, longitudinal plates, thanks to which the area for the process of photosynthesis increases. You can see these plates if you cut the sheet crosswise. The most interesting thing is that the shape of the cell at the top is different in all species.

Elongated plant cells form pairs and perform the function of transporting liquid and carrying out photosynthesis

Kukushkin flax can be used for completely different purposes:

• It can be used as inter-crown insulation due to its dense structure;
• The plant is also dried and stuffed into mattresses or pillows;
• It is used in medicine, because it contains elements that have diuretic, disinfectant and anti-inflammatory properties.

Varieties of polytrichum

Ordinary. If conditions for its growth are favorable, it can reach a length of half a meter. It is because of this that it is considered one of the longest mosses on Earth. Its leaves are toothed and have a large base. Because of this, they seem to be widely spaced along the stem. This species also grows on all continents except Antarctica, but in the tropics it is found only in the mountains. The plant prefers moist soils, lowlands, swamps and coniferous forests. It forms thick and dense turf that accumulates moisture. It turns out that the already moist soil becomes even wetter. Ultimately, this leads to the appearance of a swamp and peat formation.

juniper. Moss of this species reaches 10–15 cm in length. Its leaves have a smooth, curled edge and a short base. It also grows on all continents, but prefers taiga zones. He also loves open areas without excess moisture. For example, a wasteland or a forest after deforestation. And when no one bothers him, he literally rolls out the carpet.

Piliferous. Length 3–5 cm. Its leaves are closed by a long white hair. It grows in the same way all over the planet, but loves well-lit sandy soils without excess moisture.

Compressed. The length of the plant is no more than 20 cm. It differs from all other species precisely in its leaves: they are short, look upward and they are all almost the same size. Only the upper part of the stem has leaves, and on the lower part there is a dense cover - rhizoids, which are part of the root system.

Source: Depositphotos

Polytrichum is an aggressive plant. If the entire forest is cut down, or it burns, then the moss will very quickly take over the entire free territory

Reproduction

Moss can reproduce in two ways: asexual and sexual.

After the plant has flowered, spores are formed in capsules called sporangia, which are used to reproduce the plant. The spores are very small and light, so even a small wind can blow them away. Mature spores are transferred to the substrate. If the climate is favorable, they form threads consisting of many cells. Then, through budding, gametophytes appear from them - brown-green perennial shoots with rhizoids. They already develop independently and become adult and independent organisms.

Polytrichum is a dioecious plant that has both male and female shoots. At the end of the male stems, in the center of the leaf rosette, antheridia are formed, which contain gametes, in other words, sperm. Archegonia with mature eggs are formed on female shoots.

Fertilization process:

1. When there is a period of prolonged rainfall or flood, the sperm are separated from the antheridia and attached to the egg. They unite, resulting in the formation of a zygote - a fertilized cell.
2. After 11–13 months, a box is formed from the zygote; it is also called a sporogon; it is located on a long bare stem. Spores begin to develop in it, which are carried by the wind at a distance of 2–5 m. Then the spores germinate into a thread - a pre-plant, from which buds begin to form, which will ultimately become female and male plants.

Reproduction of cuckoo flax is an alternation of sexual and asexual methods of reproduction.

Moss can also be propagated vegetatively. To do this, place a layer of substrate with moss in a moist nutrient medium, and it will grow into a dense, thick cushion-shaped turf.

In order to occupy new spaces, ancient plants had to adapt to completely new living conditions. For example, the constant loss of moisture through evaporation contributed to the appearance of a protective waxy layer. The lack of support in the air, unlike water, caused the formation of a fairly rigid body, and the principle of gas exchange changed. The temperature and biochemical conditions became completely different, and the plants successfully adapted to them. Let's look at the life cycle of mosses in this article.

What is moss?

Mosses are a group of ancient organisms. According to some assumptions, they are the ancestors of existing land plants. Water on our planet is the source of life, in which all living things, including plants, originated. About 420 million years ago, descendants of green algae began to colonize land.

Such adaptation mechanisms can be most clearly observed in mosses. For example, the main condition for success is the availability of water. Mosses can also reproduce only with the help of moisture.

The life cycle of mosses is very interesting. Of the entire group, they are the most primitive organisms. Bryophyta or bryophytes are multicellular plants with virtually no conducting tissue. Therefore, the sizes of these living organisms are very small - from 1 mm to 50 cm. Mosses do not have roots; they are attached to the surface of the earth by thread-like outgrowths, rhizoids, with which these plants absorb water. Rhizoids sometimes consist of one cell. Unlike the roots of all other plants, which have multicellular conducting tissue. Other parts of the moss body can be roughly defined as the stem and leaves. However, in fact, they are completely different from the stems and leaves of all other plants on the planet in their structure.

Where do they meet?

Mosses have successfully adapted to life in a wide variety of temperature and climatic conditions and are distributed almost throughout the planet: from the polar regions to the tropics. They thrive in conditions of high air humidity - in forests and mountains. Mosses are also found in dry areas. The survival rate of bryophytes is amazing - they can withstand very high temperatures, up to 70 degrees Celsius. In dry climates, mosses have adapted to enter a state of suspended animation associated with seasonal climatic fluctuations. When the rains fall and the air temperature drops, the soil becomes moist and the moss “comes to life”, the reproduction cycle begins. Let's consider the importance of spores in the life cycle of mosses.

Living conditions of mosses

Moss grows happily in places with a lack of sunlight, for example, in caves, cracks and crevices of rock, occupying those ecological niches where other plants cannot exist.

The only place where mosses are unable to exist is in saline soils near the sea.

Moss spores are unusually tenacious. With the wind they can travel great distances. The spores remain viable for decades.

Mosses accumulate significant reserves of moisture, so they help regulate a particular landscape. Therefore, moss is extremely important for the ecosystem. In addition, for some animal species, moss is the main food source.

About 30 thousand species of mosses grow on earth today. Scientists classify these plants according to their morphology, the structure of the spore capsules, and the methods of spore distribution.

Mosses are able to reproduce both by spores and by vegetative means. In the life cycle of moss, the sexual generation predominates over the asexual one.

Deciduous mosses or bryopsids

This is a fairly numerous class of plants, which is represented by 15 thousand species of mosses. They are incredibly varied in appearance, size and shape. This plant consists of a stem covered with leaves that are arranged in a spiral around the stem. The very stage of their development is called gametophyte. The method of reproduction of deciduous mosses is through spores. Most often, these plants are found in damp places, swamps, and also in the tundra. Kukushkin flax and sphagnum are typical representatives of bryopsids.

Liver mosses

Liverworts are represented by two subclasses: Jungermanniaceae and Marchantiaceae. These plants are also numerous - 8.5 thousand species. Just like in deciduous mosses, the gametophyte is the stage of their greatest viability. The plant itself is a thick stem with leaves that are located along the stem. The method of reproduction is spores, which are spread using a special device, a kind of “spring” called elatera. These plants do well in humid tropical and temperate climates. Among the representatives are marchantia polymorpha, ptilidium ciliata, blepharostroma pilafolium, and others.

Anthocerotic mosses

This class is not so numerous and is represented by 300 plant species. The sporophyte is the most important life stage in the development cycle of this plant. Anthocerote mosses look like a thallus - this is a body that is not divided into roots, stems and leaves. Such mosses grow in tropical rainforests and temperate climate zones. Antoceros is a typical representative of this class.

The life cycle of cuckoo flax will be described below. Cuckoo flax moss is a perennial plant. Its structure is a fairly developed structure. The primary horizontal stem is brown without leaves and the secondary stem is erect, branched or single.

The secondary stem is covered with dark green, harsh, awl-like leaves. These stems can reach a height of 10-15 to 40 cm. The lower leaves are scales. The plant has a primitive conducting system that is capable of moving water and minerals along the stem to the leaves. Its rhizoids can reach a length of almost 40 cm.

Places where cuckoo flax moss grows

Kukushkin flax usually grows well in damp places, in swamps, damp meadows and spruce forests, and loves sunlight. In open areas it grows very powerfully, capturing more and more new territories. Its stems “envelop” the soil so tightly that seeds of other plants are unable to germinate. This plant loves cleared forests or fires. This moss absorbs water extremely well. The density of the plant retains moisture in the soil. Due to this, the area becomes swamped.

People have long used this plant as insulation. They use it to caulk the walls of log houses. Sometimes used as medicinal plant for colds.

Kukushkin flax participates in the formation of peat. It is a valuable fertilizer and a good raw material for the chemical industry.

Life cycle of cuckoo flax moss

Cuckoo flax moss is a dioecious plant. This is a phenomenon when different-sex organs - female and male - are formed on separate stems of one plant.

Kukushkin flax develops by alternating two generations - asexual and sexual. Sporophyte is the life cycle of mosses that results in the formation of asexual cells. They contain a Gametophyte - another life cycle of the same plant, which ends with the formation of gametes, sex cells containing only one set of chromosomes - haploid.

Now it is clear why the sexual generation predominates over the asexual generation in the life cycle of mosses.

Spore boxes are popularly believed to look like a cuckoo sitting on a pole. In general, the appearance of cuckoo flax moss resembles a miniature one, which is where it got its name. The fine hairs on the cap covering the spore capsule are also similar to linen yarn.

The box itself consists of several parts - an urn, a neck and a lid. There is a small column inside it. It contains infertile cells, from which haploid spores mature as a result of reduction division. The urn ends with a ring. After the ripening process is completed, this ring easily separates the urn and cap from the stem under a blow of wind. The spores fall to the ground and the important life cycle of the plant begins again.

Moss life cycle stages

Asexual spores in the process of “maturation” become haploid spores (containing half the set of chromosomes) as a result of indirect, reduction division.

When a haploid spore lands on moist soil, it begins to germinate, forming a protonema - a filamentous precursor. A gametophyte is formed from it - female or male.

At the tops of different gametophyte stalks of cuckoo flax, antheridia and archegonia develop - male and female reproductive organs. Oocytes mature in archegonia, and biflagellate spermatozoa mature in antheridia. Externally, male plants are distinguished by large yellowish-brown leaves at the top. Female plants do not have such leaves.

For successful fertilization, drops of moisture are needed to transport sperm from the antheridia to the archegonia, where the eggs are located. This process is usually facilitated by rain or heavy dew.

As a result of the fusion of sperm and egg, a diploid zygote is formed at the top of the female plant. From it grows a new generation of this plant, a sporophyte or sporogon. And it is a sporangium box in which spores ripen.

We examined the sequence of stages of the moss life cycle.

The structure of cuckoo flax moss

The body of mosses is similar in structure to algae, since it also consists of a thallus. However, it may have a structure resembling stems and leaves. Attached to the soil using rhizoids. These plants are able to absorb water and minerals not only directly through the rhizoids, but throughout the body.

The value of moss in nature

In general, mosses are an essential component of the ecological system of our planet. The life cycle of mosses differs from that of other higher plants. They survive well in nutrient-poor soils. They inhabit places that have been subjected to adverse anthropogenic impacts. Thus preparing the land for restoration. After all, when moss dies, it forms a useful soil substrate on which other plants will subsequently grow.

Mosses are indicators of pollution environment, in particular, the atmosphere. Because some types of mosses do not grow in places where the concentration of sulfur dioxide in the air is exceeded. The absence of certain types of mosses in traditional habitats can also indicate air pollution. However, mosses also indicate changes in soils, and much more.

Mosses protect the fragile balance in permafrost areas, covering the soil from the sun's rays. Thus maintaining ecological balance.

Now, if you are asked: “Characterize the life cycle of moss,” then you can easily do it.