Mosses and lichens are 100% space pioneers. It was they who first "came out" on land, adapted to life on it, and also became the material for the formation of humus. In addition, mosses and lichens underlie the evolution of plants.

What are mosses and lichens

• mosses- these are higher spore plants that belong to the department of the Moss-like kingdom of Plants.
• Lichens- lower plants formed by the symbiosis of fungi and bacteria.

Comparison of mosses and lichens

What is the difference between mosses and lichens?

Mosses appeared on Earth at the end of the Devonian - at the beginning of the Carboniferous period. Mosses are present on all continents, including Antarctica. The only condition necessary for the life of mosses is the presence of a sufficient amount of moisture required for the organization of the reproduction process.

Lichens appeared in the early Devonian. They are distributed on all continents and were able to adapt to life and rise to the maximum height for plants in mountainous areas.

mosses are miniature plants. They have no roots, so they are attached to the substrate with the help of multicellular hair-like processes - rhizoids. In addition to fixing in the soil, rhizoids play the role of delivering water and nutrients to the body. But these same substances can enter the plant through the stem and leaves. The leaves and stems of mosses contain chlorophyll, becoming the site for the process of photosynthesis.

Lichens These are amazing plants. Their body - thallus - is formed by the cohabitation of fungi and algae. But forcibly separated components of the lichen organism are able to exist independently. In the lichen thallus, fungal hyphae form an upper and lower crust. And in the middle, like a filling in a pie, there are algae. They are involved in photosynthesis, possessing the pigment chlorophyll. Lichens do not have roots. As a result of life processes, fungal hyphae release acid, destroying the substrate to which they are attached.

mosses are dioecious plants. Female individuals at their tops have organs containing eggs, and male organisms have organs containing spermatozoa. They are sporophytes, one of two generations that dominate the moss life cycle. After pollination, a sporangium is formed on the female plant. Spores ripen in it, which, having fallen into a humid environment, germinate. From this green thread - the gametophyte - new female and male individuals grow over time.

Lichens can reproduce vegetatively, asexually and sexually, forming characteristic fruiting bodies.
Moss retains water in the soil, sometimes swamping it. Mosses were the first dressing material and are the basis for the formation of peat.

Not enduring pollution in the atmosphere, lichens have become ideal indicators of the state of the air. Lichens are considered biological destroyers of rocks and the basis of the soil formation process.

The difference between mosses and lichens is as follows:

• Lichens appeared on Earth earlier than mosses and have a wider area of ​​distribution.
• Moss is a single organism, lichen is a conglomeration of organisms capable of independent existence.
• Mosses are at a higher evolutionary stage of development than lichens.
• Both plants have different biological and economic importance.

Tests

620-1. The accumulation of what group of plants contributes to waterlogging of the soil?
A) lycopsform
B) horsetail
B) mossy
D) ferns

Answer

620-2. The stem with leaves in the process of evolution first appeared in
A) algae
B) mossy
B) horsetail
D) ferns

Answer

620-3. Mosses represent a dead end branch in plant evolution because
A) more highly organized ferns originated from them
B) they did not give rise to more highly organized plants
C) more highly organized horsetails originated from them
D) they evolved from unicellular algae

Answer

620-4. What are the characteristics of mosses?
A) adventitious roots develop from the stem
B) spores are formed in a box
C) they have no escape
D) pollination precedes fertilization

Answer

620-5. Mosses develop from spores
A) a box on a leg
B) seed
B) green thread
D) sprout

Answer

620-6. The adaptability of sphagnum moss to life in conditions of excessive moisture is manifested in the presence of
A) rhizomes with adventitious roots
B) cells with chloroplasts
B) dead cells
D) rhizoids

Answer

620-7. Representatives of which department of the plant kingdom are shown in the figure?

Answer

620-8. What plants belong to the Bryophytes department?
A) living on land and reproducing by seeds
B) leafy, without roots, reproducing by spores
C) all plants in wet habitats
D) all herbaceous plants

Answer

620-9) What adaptations to the absorption of large amounts of water appeared in the process of evolution in mosses?
A) rhizoids - outgrowths on the stem
B) large dead cells
B) spore boxes
D) cells of thin integumentary tissue

Answer

620-10. In green mosses, unlike algae,
A) cells have large and small nuclei
B) fertilization occurs in the presence of water
C) the thallus is divided into tissues and organs
D) sexual and asexual reproduction

Answer

620-11. What division of higher plants does the plant shown in the picture belong to?

A) angiosperms
B) Gymnosperms
B) ferns
D) Bryophytes

Answer

620-12. How are bryophytes distinguished from other plants?
A) in the process of their development, alternation of generations occurs
B) reproduce by spores
B) have leaves, stem and rhizoids
D) capable of photosynthesis

Answer

620-13. Ferns, unlike green mosses, have
A) rhizoids
B) roots
B) leaves
D) stems

Answer

620-14. From spores of green moss cuckoo flax develops (s)
A) a growth in the form of a green plate
B) pregrowth in the form of green threads
B) plants with leaves
D) seeds of the future plant

Answer

620-15. Higher plants have no roots
A) Tsvetkov
B) conifers
B) moss
D) Ferns

Answer

620-16. Ferns are much more widespread on Earth than mosses, since they
A) have a developed root system and multiply more efficiently
B) appeared in the course of evolution earlier and managed to better adapt
C) are widely grown by man for their needs
D) successfully distributed by various animals

Answer

620-17. Mosses have the simplest structure among higher plants, since
A) they have no roots
B) their stem is unbranched, with narrow leaves
C) they form organic substances from inorganic
D) they have air cells

Answer

620-18. Why do mosses represent a dead end in plant evolution?
A) they have not mastered the ground-air habitat
B) they evolved from algae
C) they do not have roots and reproduce by spores
D) they did not give rise to more highly organized plants

Answer

620-19. What department of the plant kingdom is represented in the picture?

A) ferns
B) Gymnosperms
B) Lycopsoid
D) Mossy

Answer

620-20. Which group of organisms include green plants that do not have roots, multiply by spores, in the life cycle of which the sexual generation predominates?
A) bryophytes
B) ferns
B) gymnosperms
D) lycopsform

To systematize knowledge, I suggest filling out the following table:

Subject: Bryophytes. Moss characteristics.

Purpose: 1. To introduce students to the characteristic features of higher plants using mosses as an example. 2. Show features of complication in the organization of mosses (compared to algae).

Equipment: live plants or herbarium specimens of cuckoo flax, sphagnum or other mosses; microscopes; tables.

instruction card.

1. Consider the external structure of the moss. Find the stem and leaves. Indicate the shape, location, size and color of the leaves, the nature of the stem (branched, not branched).

2. Examine the top of the stem and find the spore box. Establish the importance of spores in plant life.

3. Examine a leaf of moss under a microscope and draw it in a notebook, sign the names of the main parts of the leaf.

4. Answer the questions: how do mosses differ from algae and flowering plants in structure? What are the similarities and differences in the nutrition of mosses and flowering plants?

2. Physiological characteristics of plants

Topic: Cellular structure of the root.

Purpose: To study the features of the external and internal cellular structure of the root.

Equipment: Sprouted bulbs of onions with water, sprouts of radish, lettuce, wheat, coverslips and glass slides, a glass of water, a dissecting needle, micropreparations of the root cap, root hairs, absorbing area.

instruction card.

1. Examine the roots of onions with the naked eye and with a magnifying glass. Find a root cap. Examine the micropreparation of the root cap under a microscope. Draw the cellular structure of the cap. Label its parts.

2. Find areas with root hairs on the roots of radish, wheat, lettuce. Mark their location on the root. Draw the root and root hairs. Label each section of the root.

3. Examine it with a microscope. Find a root hair and examine it. Sketch the root hair and label all its parts. Why has the shape of the cell changed?

4. Consider a transverse section of the conductive section of the root. Locate root vessels. Sketch the cellular structure of this section of the root. Locate root vessels. Sketch the cellular structure of this section of the root.

5. Compare the internal structure of the fruits of tomato and watermelon and the structure of the root. Find similarities and differences. How to explain the features of plant tissues of the root, draw a conclusion.

Topic: The structure of the stem.

Purpose: To study the internal structure of the stem on the example of coniferous and deciduous trees.

Equipment: parts of tree stems, dissecting needles, an album.

instruction card.

1. Consider the transverse and longitudinal sections of the branches and find the layers of the stem of a woody plant.

2. On the longitudinal section of the branch, separate the bark, determine the property of the wood surface by touch, find an explanation of this property in the text of the textbook.

3. Examine the structure of the bark, wood and core with a magnifying glass. With a dissecting needle, select parts of the bark (cork and bast fibers), wood and core. Place them in the laboratory place and write the names of each of these parts.

4. Design the application “Structure of a woody plant”, draw a longitudinal section of a branch in a notebook and sign the name of each layer, using the appropriate text and drawing from the textbook.

Subject: Modified shoots.

Purpose: To investigate the shoots of potato tubers in connection with their functions.

Equipment: potato tubers, scalpel, album.

We begin to acquaint students with modified shoots during a conversation about the importance of potatoes (food, fodder and industrial crops). In order to update the knowledge previously acquired by students about the organs of a flowering plant, we propose for discussion the question: can a potato tuber be called a root, leaf, flower, fruit? As a result, a problematic situation is created (what is a potato tuber?) and the need to solve an educational problem, during which students must refute erroneous assumptions and prove that a potato tuber is a modified shoot.

The solution to this problem is carried out in the following sequence: students list the signs of the fruit and the shoot, find out which of these signs are inherent in the tuber, and conclude that the tuber is a modified shoot. They are convinced of this in the course of laboratory work involving the study of the external and internal structure of the tuber. Carrying out work on the instruction card.

instruction card.

1. Examine the tuber, find the buds. Draw the outline of the tuber and mark the eyes and the kidneys located in them.

2. Remember how the kidneys are located on the tuber.

3. Count the number of eyes on the tuber; more of them are located at the top, less - at the base; determine where the tuber has the top, where is the base.

4. Examine thin transverse sections of a potato tuber to the light and find parts of the stem; draw the structure of a cross section of a potato tuber; prepare an answer to the question: why do peeled new potatoes slide in your hands?

5. Compare the internal structure of the linden stem and the internal structure of the tuber; explain the differences.

Topic: The movement of water through the plant

Purpose: To get acquainted with the principle of water flow to the leaves and buds of a plant.

Equipment: cross sections of tree species of plants, albums.

The study of the question of the movement of water and minerals along the stem begins with a repetition of the material on the root, the flow of water and minerals into the plant, the relationship between the structure and function of the root. We talk about the structure and functions of the leaf and invite students to answer the question: on which part of the stem does water rise to the leaves?

We conclude the discussion of this topic with a demonstration of an experiment proving that water and mineral salts move along the stem wood, and I invite students to study the results of this experiment, guided by an instruction card when doing laboratory work.

instruction card.

1. Consider the transverse and longitudinal sections of linden branches placed in tinted water.

2. Sketch them, sign the names of the layers, use a colored pencil to depict the results of the experiment.

3. Explain why the wood was stained, and not the core and bark.

3. Ecological features of plants.

Topic: "The variety of inflorescences of flowering plants."

Purpose: 1. To get acquainted with the structure of simple and complex inflorescences. Learn to recognize the types of inflorescences.

In this lesson, we get acquainted with the variety of inflorescences in connection with the attraction of insects for pollination.

Mosses are among the higher plants. However, this is the most ancient and simply organized group. At the same time, bryophytes are very diverse and numerous and are inferior in number of species only to flowering plants. There are about 25 thousand species of mosses.

The vast majority of mosses are perennial plants, their height is from a few millimeters to 20 cm. Mosses grow only in well-moistened areas.

Mosses have a semblance of roots - rhizoids that absorb water and fix the plant in the soil. In addition to the main and photosynthetic tissue, mosses do not have other tissues.

So mosses do not have integumentary, mechanical, conductive and storage tissues.

Department Mosses (Bryophytes) is divided into two classes - Liver mosses and Leafy mosses.

Liverworts are the most ancient mosses. Their body is represented by a branched flat thallus. There are many liverworts in the tropics. Marchantia moss grows in damp places that are not overgrown with grass. Marchantia has a creeping thallus that looks like a leaf blade. In the upper part of its thallus there is a photosynthetic tissue, in the lower part - the main one. Another representative of mosses is Riccia.

In leafy mosses, the body has shoots consisting of stems and leaves. A typical representative is the cuckoo flax, which is often found in coniferous forests and tundra, near sphagnum bogs and in damp places. It is a plant more than 10 cm tall.

Mosses have asexual and sexual reproduction. Asexual reproduction is represented both by vegetative reproduction, when the plant reproduces by parts of the thallus, stems or leaves, and by spore reproduction.

During sexual reproduction, mosses grow special organs in the upper part of the body. They form gametes - mobile spermatozoa and immobile eggs. The spermatozoa move along the water to the egg and fertilize it. After fertilization, the so-called box with spores grows on the plant. After maturation, the spores disintegrate and spread over long distances.

The spore, once in a favorable environment, develops into a multicellular green thread protonema, on which thalli or shoots then grow.

Kukushkin flax can lead to waterlogging of the soil, as it creates dense covers on the soil, which leads to the accumulation of water. Where the cuckoo flax grows, another representative of the moss may appear - sphagnum (white moss). In its leaves, cells with chlorophyll alternate with large cells containing air and water. Sphagnum can quickly accumulate water in the body and further contribute to the waterlogging of the soil. The dead parts of sphagnum are part of peat.

Biology
5th grade

§ 20. Mosses

1. What are rhizoids?
2. Why are algae classified as lower plants?
3. What is a dispute?

Mosses are distributed mainly in well-moistened places and only occasionally in arid areas (during the dry period they are at rest and resume their vital activity when precipitation falls).

Unlike algae, mosses have a stem and leaves, with the exception of a number of species of primitive liver mosses, in which the body is represented by a thallus. Mosses do not have real roots, they are replaced by rhizoids, with which they strengthen themselves in the soil and absorb water.

Since the body of mosses is divided into stems and leaves, and they reproduce by spores, they are classified as higher spore plants.

There are hepatic and leafy mosses.

liver mosses. Those who have an aquarium at home are well aware of the floating plant that covers the surface of the water with a green carpet. This is one of the liver mosses - Riccia (Fig. 68). Its body consists of a forked branched thallus. In good light, Riccia grows rapidly, forming dense cushions on the surface of the water.

Rice. 68. Liver mosses

Floating Riccia does not have rhizoids, but when water bodies dry up, remaining on damp soil, it can form them. Various types of liver mosses are found in damp forests, swamps, and reservoirs.

Leafy mosses. One of the most famous leafy green mosses is cuckoo flax (Fig. 69), it can often be found in swampy or simply wet places. Its slender brownish stems are covered with small dark green leaves and look like miniature flax plants.

Mosses - ancient and important

69. Moss cuckoo flax

Cuckoo flax has male and female plants. At the tops of male plants are the reproductive organs, in which mobile sex cells (gametes) develop - spermatozoa (from the Greek words "sperm" - seed, "zoon" - a living being and "eidos" - species).

In female plants, the genital organs are located at the tops with the female reproductive cell (gamete) - the egg.

On female plants, boxes on long legs develop, covered with hairy pointed caps. They look like a sitting cuckoo. Hence the name of the moss - cuckoo flax. Spores develop in the boxes. Spilling out and germinating, they form new moss plants.

Kukushkin flax is a perennial plant. Covering the soil in damp places with a continuous carpet, it often crowds out other green mosses.

moss structure

1. Consider a moss plant. Determine the features of its external structure, find the stem and leaves.
2. Determine the shape, location, size and color of the leaves. Examine the leaf under a microscope and draw it.
3. Determine if the plant has a branched or unbranched stem.
4. Examine the tops of the stem, find male and female plants.
5. Examine the spore box. What is the importance of spores in the life of mosses?
6. Compare the structure of moss with that of algae. What are their similarities and differences?
7. Write down your answers to the questions.

The representative of white, or sphagnum, mosses is sphagnum.

Sphagnum is a plant with a strongly branching stem (Fig. 70). Unlike cuckoo flax and other green mosses, it does not have rhizoids. The stem and branches of most sphagnum species are covered with small light green leaves. Each leaf consists of one layer of cells. These two different types of cells, their differences are clearly visible under a microscope.

Rice. 70. Moss sphagnum

Narrow green cells containing chloroplasts are connected to each other and form a continuous network. Organic substances are formed in these cells, which come from the leaves to the stem.

Between the green cells are other, larger ones. Their cytoplasm is destroyed, only shells with holes are preserved, so these dead cells are transparent and can be filled with water or air. Up to 2/3 of the leaf surface consists of these cells. Thanks to this structure, sphagnum quickly absorbs and conducts water.

Outside, the stems are also covered with transparent dead cells. Dead cells of sphagnum leaves and stems are able to absorb water 20-25 times their mass, hold it for a long time, gradually giving it to living cells.

Usually sphagnum grows on raised bogs, covering the surface of the soil with a continuous carpet, but it can also grow under the forest canopy among cuckoo flax. Where sphagnum settled, the soils are waterlogged. On excessively moist soil, trees grow poorly, become oppressed, and sphagnum, on the contrary, grows into a lush carpet, and the forest gradually becomes swampy.

Sphagnum reproduces by spores, just like cuckoo flax and other mosses. At the ends of the upper branches, it forms small boxes in which spores ripen.

The value of mosses in nature and human life. Mosses, settling in meadows, in forests, cover the soil with a continuous carpet, making it difficult for air to enter.

This leads to acidification and waterlogging of the soil.

Leaf-stemmed, especially sphagnum, mosses cover swamps with a continuous carpet and, dying, form peat, which is widely used by man. Peat is used as a fuel, fertilizer and as a raw material for industry. Wood alcohol, carbolic acid, plastics, insulating tapes, resins and many other valuable materials are obtained from peat.

New concepts

Moss. Spore. Higher spore plant. Sperm. Egg

Questions

1. Why are mosses called higher spore plants?
2. What is the structure of cuckoo flax?
3. How is sphagnum different from cuckoo flax?
4. How is moss different from algae?
5. What is the importance of mosses in nature and human life?

Think

Why don't even the largest mosses reach sizes over 80 cm?

Quests for the curious

1. Examine the leaves of sphagnum moss under a microscope. Note the structural features of the two types of cells of which they are composed.
2. Place some Riccia in a jar of damp soil. Cover the jar with glass and place in a warm, bright place. Make sure the soil is constantly moist. Watch what happens with Riccia.

Do you know that…

• Stumps and roots of trees, leaves and pollen of plants that lived millennia ago are preserved in peat layers. They are not completely destroyed, since there is little oxygen in the peat layer, in addition, sphagnum secretes substances that prevent the development of bacteria. When draining and developing swamps, well-preserved old boats, the remains of animals and people who died in the swamp are sometimes found in the thickness of peat.
• Sphagnum was widely used during the war years as a substitute for cotton wool because of its high moisture capacity and good bactericidal properties.

Mosses are a group of higher plants. They are distinguished by such a complex structure and diversity that a whole science has been formed, which studies them - bryology.

Despite the fact that bryophytes belong to higher plants, they have there are no roots and flowers, but they reproduce with the help of spores and vegetatively.

These plants are widespread everywhere - they can be found even in Antarctica, they are so unpretentious and resistant to any climate.

Mosses are undersized, perennial plants, from 1 mm to 60 cm high. They grow on trees, earth, stones, house walls, in fresh water bodies and in swamps.

Moss is one of the oldest plants on Earth. His age - about 300 million years.

moss species

First of all, it is necessary to distinguish between bryophytes and mosses proper. Modern science recognizes three classes of bryophytes:

• bryophytes;
• liverworts;
• anthocerotes.

Of these, only the first class belongs to real mosses. The remaining classes have recently been considered as independent botanical departments.

The largest class of bryophytes - leafy mosses. There are more than 14 thousand species of them, and they make up 95% of all bryophytes.

The name of this class reflects its appearance and structure - plants consist of stems with outgrowths covering them, leaves of various shapes, arranged in a spiral.

On the underground part of the stems, instead of roots, there are rhizoids - long filamentous outgrowths. With their help, the plant draws water and minerals from the soil.

Complex structure, unique reproduction process, ability to fall into a state of suspended animation helps mosses survive in any climatic conditions and play a leading role in many plant communities - in the tundra, mossy forests, etc.

The most famous subclass of leafy mosses is green. It includes, in particular, such an aquatic plant popular with aquarists as Java moss.

plant kingdom

With it, the aquarium becomes green and beautiful; the plant is easily attached, and aquarium fish like to spawn in its leaves.

About 1500 species of bryophytes live on the territory of Russia, of which the most common are:

• Kukushkin lyon. It is found in forests and meadows of central Russia, has a bright green color.
• Sphagnum, or peat moss. The main place of distribution is swamps, it is distinguished by a lighter color.

The difference between mosses and lichens and ferns

Moss is often confused with lichen. Examples: Icelandic moss and reindeer moss are actually lichens. Icelandic moss is known for its medicinal properties - it is used to treat tuberculosis, colds, and restore strength.

The difference between mosses and lichens is that lichens are of more ancient origin and are representatives of lower spore plants.

But ferns occupy a higher stage of evolution, and they have a vascular conducting system. Unites plants method of reproduction: both of them use spores for this, not seeds.

The value of moss

The importance of mosses in nature and human life is enormous. Bryophytes:

• Pioneers. They are the first to develop lands with adverse climatic conditions.
• Regulate the water balance in the soil.
• Sphagnum is a source of peat, a mineral used as fuel and fertilizer.
• They have disinfecting properties.
• Accumulate and retain radioactive substances.
• They are a food source for many animal species.
• Protect soil from erosion.

However, the spread of mosses can lead to waterlogging of agricultural land.

Mosses play a leading role in the formation of special natural complexes. For example, tundra.

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Bryophytes department, their classification, ecological features and indicator value.

Mosses do not have flowers, roots, or a conducting system. Mosses reproduce by spores that mature in sporangia on sporophytes. In the life cycle, unlike vascular plants, the haploid (that is, with a single set of unpaired chromosomes) gametophyte (sexual generation) predominates. The moss gametophyte is a perennial green plant, often with leaf-like lateral outgrowths and root-like outgrowths (rhizoids), while the sporophyte (or asexual stage of the life cycle) is short-lived, dries quickly and consists only of a stem and a box in which spores mature.

The moss sporophyte (named sporogony, or sporogon), has a simpler structure than other groups of higher plants. It is not able to take root and is located on the gametophyte. The sporophyte usually consists of three elements:

a box (or sporangium) in which spores develop;

The stem (or sporophore) on which the box is located;

feet, providing a physiological connection with the gametophyte.

In nature:

· Participate in the creation of special biocenoses, especially where the soil is almost completely covered (tundra).

Moss cover is able to accumulate and retain radioactive substances.

· They play an important role in regulating the water balance of landscapes, as they are able to absorb and retain large amounts of water.

In human activities:

· May impair the productivity of agricultural lands, contributing to their waterlogging.

· Protect the soil from erosion, providing a uniform transfer of surface water runoff into underground.

Some sphagnum mosses are used in medicine (as dressings if necessary).

· Sphagnum mosses are a source of peat formation.

MHI(bryophytes), department of higher plants. Includes 22–27 thousand species. Anthocerotus mosses are distinguished, liver mosses And leafy mosses. Known from the Carboniferous. Distributed everywhere.

How do mosses and ferns differ from flowering plants?

They are of particular importance in the tundra, where they play a landscape role. In the tropics, they are common high in the mountains, where a special belt of mossy forests is located. Most mosses are perennial stunted plants. They differ in a relatively simple internal organization (they have poorly expressed conductive, mechanical, storage and integumentary tissues). Mosses are devoid of roots, dissected into stems and leaves, or form a thallus (thallus) creeping along the ground. Monoecious, dioecious or polyecious plants. IN alternation of generations in mosses, the gametophyte (sexual generation) dominates. Along with ensuring sexual reproduction, it performs the main vegetative functions (photosynthesis, water supply, mineral nutrition). The sporophyte (asexual generation) is poorly developed, it is always connected with the gametophyte (they exist together on the same plant) and is never divided into stem and leaves.

The organs of sexual reproduction - antheridia (male) and archegonia (female) are more often located on the plant in groups, usually surrounded by leaf-shaped outgrowths or other protective formations. Fertilization of the egg by motile two-flagellated spermatozoa, which are formed in the antheridia, is possible only in the presence of drip-liquid water. The fusion of gametes and the development of the zygote takes place inside the archegonium. Within a certain time (from several months to 2 years), a multicellular diploid sporophyte (a specialized reproductive organ), called sporogon, develops from the zygote for a certain time (from several months to 2 years). It consists of the upper spore-bearing part (box) and the lower - legs with a foot growing into the tissue of the gametophyte. From the spores formed by reduction division, a multicellular branched filamentous or lamellar formation develops - a protonema, on which buds are laid, giving rise to lamellar thalli or leafy shoots - gametophores. The mass participation of mosses in the vegetation cover has a significant impact on the habitat of other plants and animals. In areas of increased moisture in temperate zones, significant (up to 11 m thick) peat deposits accumulate with a predominance of mosses.

Some mosses ( sphagnum) have antibiotic properties and are used in medicine.

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Variety of mosses. Their role in nature and human life

Variety of mosses. Bryophytes are common in all climatic zones of land. In our time, more than 25 thousand species of mosses are known (in Ukraine - about 800). These are predominantly perennial, rarely annual herbaceous plants. The green stems of individuals of the sexual generation in different species are from 1–2 mm to one meter long. Mosses grow on the surface of the soil almost everywhere - from swamps to deserts, some species have mastered fresh water. The largest number of species grows in well-moistened places - moist forests, meadows, etc. In swamps and tundra, mosses form the basis of plant communities. Often they settle on trees and rocks. Mosses growing in deserts can remain viable for several years, being in a dried state.

Over 300 species of the genus Sphagnum are distributed in swamps and other waterlogged places, mainly in the Northern Hemisphere. Sphagnum stems reach a height of 50 cm. Plants branch strongly at the top and are devoid of rhizoids. Leaves are made up of two types of cells: some are living and some are dead. Living cells are green and photosynthesis takes place in them. Dead cells are colorless, their membranes have pores through which they absorb water.

Among sphagnums, there are both monoecious and dioecious species. Sphagnums grow at the top, and the lower part of the stem gradually dies off. Dead parts of plants are immersed in water. Since there is usually little oxygen in swamp water, and sphagnum secretes acids that kill microorganisms, its dead parts do not rot. They settle at the bottom of the swamps for tens, hundreds and thousands of years, are compressed and form peat. Peat layers can sometimes reach several tens of meters in thickness. But the rate of peat formation is insignificant: in ten years, a layer no thicker than one centimeter is deposited.

The value of moss in nature and human life. Mosses are not demanding on growing conditions, they can settle where other plants are absent.

What is moss? Structure, reproduction, types of mosses, their meaning and application

By releasing acids, mosses cause the gradual destruction of rocks, and their dead parts accumulate between the debris. This is how primary soils arise, on which other plants settle over time. Interestingly, animals almost do not eat mosses. This contributes to the accumulation of their residues in the soil and, thus, to an increase in humus reserves.

A continuous layer of living mosses and their dead parts in the forests and tundra prevents the evaporation of water and contributes to its preservation in the soil. Often this leads to swamping, that is, the formation of swamps in places of forests and other plant communities. Wetlands play an exceptional role in maintaining the flow of rivers, since it is from them that streams and small rivers originate. But with an increase in the degree of waterlogging of the area, the area of ​​​​arable land may decrease.

An important role in human economic activity is played by peat, the world reserves of which are estimated at 270 billion tons. Peat is used as organic fertilizer and fuel. In the form of pressed boards, it is used in construction as a heat-insulating material. In the chemical industry, peat serves as a raw material for the production of plastics, paints, varnishes, alcohols, acids, etc. Dried sphagnum has disinfecting (antibacterial) properties, so it was previously used for wound dressing.

In the mountains of Europe, in particular in the Carpathians, a special type of moss is found on rocks and in caves. The green thread growing from the spores of this moss lives for a long time, reaching a considerable size, and is capable of glowing in the semi-darkness. Special lenticular cells capture weak light and direct it to chloroplasts, creating conditions for photosynthesis. Light passing through the chloroplast is reflected by the cell wall as a green beam. The glow of this moss gave rise to folk legends about gnomes who guard treasures in caves with lanterns at night.

Aquatic moss fontinalis, the sexual generation of which looks like branched creeping stems, is used by aquarists during the spawning of ornamental fish. Caviar, located among densely intertwined moss shoots, is reliably protected from being eaten by other inhabitants of the aquarium and from the action of harmful microorganisms, since moss releases special substances that kill them.

Bolls of different types of mosses contain from several tens to a million spores with a diameter of 5 to 200 microns. Moss spores do not lose their ability to germinate after being kept for several hours at a temperature of -200 °C or short-term heating to +100 °C.

Flipping through the pages of biology:

Ferns
Lycopsids and horsetails
General characteristics of seed plants
Types of roots. Types of root systems
Root structure
The root is an organ that provides mineral nutrition to plants.
Root modifications and their functions
Escape and its structure. Escape development from the kidney
Biology (content)

To understand what mosses are, you need to study the most ancient eta - the highest type, isolated and numerous. In our time, there are almost 30 thousand varieties of mosses on the entire planet.

Classification

Botanists have discovered and studied all known species, the classification of which is based on differences in the morphological structure, methods of distribution and the structure of spore boxes. can be conditionally divided into the following classes: deciduous, liverwort and anthocerot mosses.

Deciduous mosses

What are deciduous mosses? They are otherwise called briopsids. This is a large class with about 15 thousand species. Representatives of this group are recognized as the most highly developed of all plants of this department. Briopsids are very diverse, both in shape and size. Sometimes they reach considerable sizes. The most viable stage of their existence is the gametophyte. The plant looks like a stem with single-layer leaves arranged in a spiral. Bryopsids reproduce by spores. They are distributed in the tundra, swampy and humid areas. Representatives: cuckoo flax,

liver mosses

What are hepatic mosses (liverworts)? They number about 8.5 thousand species and are divided into two subclasses: Marchantium and Jungermann liverworts. The predominant viable stage is the gametophyte. Externally, the plant resembles a flattened "stem" with leaves arranged along. Propagated by spores with the help of an elater (special spring). Liverworts are common in tropical and temperate climates. Typical representatives: hairy blepharostroma, polymorphic marchantia, barbilophosia lycopsus, ciliated ptylidium.

Anthocerotus mosses

What are Anthocerote mosses? This class of mosses is often regarded by specialists as a subclass of liver mosses. It includes almost 300 species.

The sporophyte stage predominates. Externally, the plant looks like a rosette-like or lobed thallus. These mosses are found in temperate humid and tropical climates. The representative of the class is anthoceros.

Generalized characteristics of mosses

So what are mosses? These are undersized plants, the height of which can vary from 1 mm to 60 centimeters. They grow on tree trunks, on the walls of houses, on the ground, in fresh water and swamps. Due to salt intolerance, plants are not found in the seas and on saline soils. Most often, the structure of mosses is very simple - stems and leaves. But the roots of the plants in question are completely absent. They absorb water and nutrients with rhizoids or the whole body. Adaptation to terrestrial existence has led to the fact that mosses have integumentary and mechanical tissues, as well as new cells that perform a conductive function. The plant is a perennial, most often small in size (only a few mm high), less often large (up to 60 cm). Its body looks like a thallus (anthocerotic or individual liverworts) or is divided into a “stem” and “leaves”. Attachment to the substrate and absorption of water is carried out by outgrowths of cells, the so-called rhizoids (they, as a rule, do not have a conducting system).

It also does not differ in intricacy. These are large light green or slightly reddish curtains. They have upright "stems", with clustered leafy "branches". Without rhizoids, the moss stem is upright (gradually dying from below), leafy in several rows, with numerous leafy lateral processes, which are collected at the top of the stem into a dense head. Throughout the rest of the stem, the branches are collected in bunches. The latter consist of 3-13 branches hanging and spaced from the stem. At the top, the “branches” shorten and gather into a dense head. Colorless aquifers with pores make up the outer layer of the “stem”.

Single-layer "leaves" of sphagnum include two types of cells: photosynthetic and aquifers. The first are worm-shaped and contain chloroplasts located between aquifers. There are many such cells, which allows the sphagnum to absorb a large amount of water. Sphagnum sporophyte is a rounded box in which spores appear, with a lid. When the spores mature, the pressure inside the box increases, as a result of which the lid opens, and the ripe spores are thrown out. This process takes place in warm weather for better spore dispersal.

What are green mosses? Kukushkin flax can be attributed to their bright representatives. Its “stem” is covered with hard, dark green subulate “leaves”. It has rhizoids and grows up to 30-40 cm. The leaves of the moss are recurved and erect, with an elongated membranous sheath and a vein protruding from the top. The “stem” has a primitive conducting system and dioecious gametophytes. The top of the "stems" ends with antheridia and archegonia. After fertilization, a sporophyte develops from the zygote, which is a box on a long stalk for the maturation of haploid spores in it. The box is covered with a falling cap with thin, drooping hairs, similar to linen yarn. The moss box is subdivided into a lid, a neck and an urn. Inside the box is a "hidden" column filled with barren cells. Around the column is the sporangium. The urn and the lid adjoin a ring consisting of cells with thickened walls. This ring is responsible for dropping the urn and separating it from the lid.

Moss propagation methods

The sexual generation predominates over the asexual one. The reproductive organs of moss are formed directly on its body. These are the archegonia and antheridia mentioned above. Archegonia are responsible for the formation and development of one immobile female gamete, and antheridia are responsible for many male gametes. In the fertilized female gamete (the condition is the presence of water), the asexual generation of moss begins to develop - the sporophyte. This is a kind of box on a leg, attached to the body of the moss. It contains many spores that are able to germinate under favorable conditions, forming a new plant. Some species are able to reproduce vegetatively. At the same time, the thallus is separated from the adult organism, which is attached in close proximity to the plant, and begins an independent existence and reproduction.

moss spread

It is more difficult to determine where there is no moss than to tell where moss grows. This representative of the flora is distributed almost everywhere - from the tropics to the polar regions. In tropical regions, moss grows mainly in mountainous areas and in forests, i.e., where high humidity prevails. Sometimes soil covered with mosses is also found in arid areas, since this plant has the ability to temporarily stop its vital activity during the dry period, and resume it with the advent of moisture. Basically, mosses predominate in the temperate and subarctic zones of the northern hemisphere.

Moss and its meaning

The value of mosses in nature is enormous. Firstly, thanks to these representatives of the plant world, the landscape water balance is regulated, because they are able to accumulate large reserves of moisture in the thallus. Secondly, the moss plant creates a special biocenosis, especially in areas where it completely covers the soil. In addition, this group has the ability to accumulate and retain radiation. The value of mosses for animals is also great, because bryophytes are the main type of food for some individuals. And in human life, this plant also plays an important role. So, many species are effectively used in pharmacology. And the peat formed after the death of mosses is used as fuel.

And algae, the features of their structure and physiology have been known to scientists for a long time. In appearance, these plants are very similar. However, they are representatives of completely different systematic units. In our article, we will look at how moss differs from algae.

plant classification

There are no plants in nature! The diversity of plants is simply amazing: algae, mosses, ferns, gymnosperms, flowering plants ... It’s impossible to list everything. However, taxonomists managed to combine them into various groups based on the totality of the main features of the structure.

Comparison of mosses and algae

Why are mosses, ferns, algae, lichens plants? All these organisms are capable of photosynthesis, since they contain green plastids chloroplasts in their cells. The most primitive of them live in water. These are algae, which are a group of lower plants. Mosses are typical. However, their reproduction is possible only in the presence of water. Therefore, they prefer damp places.

Outwardly, algae and mosses are very similar. Therefore, they are often confused. Not all algae grow exclusively in water. Some of them settle on tree trunks, rock surfaces, wet areas of soil, on snow, in animal hair. They form a continuous green cover, like bryophytes. Blue-green algae are able to enter into symbiosis with fungal hyphae, forming lichens.

Characteristics of lower plants

Algae are called inferior because their body is a collection of cells (there is no division into root, stem and leaves). It is called slan, thallus or thallus. Algal cells are not specialized. They are connected anatomically, but each of them performs similar functions. With the help of rhizoids, algae are attached to the substrate. This structure also does not form tissues, therefore it is not capable of performing a conductive function. Yes, and there is no need for it, since the lower ones grow exclusively in water.

Higher spore plants - natives to land

Due to climate change, plants have had to adapt to the terrestrial environment. The first representatives of this ecological group arose in the Devonian. This is a group called rhinophytes. Their prints are well preserved in ancient fossils. These are the first plants that have elements of conductive tissues. Therefore, they are also called vascular. Their ribbed stems branched forked, and rhizoids were still preserved instead of roots.

The rhyniophytes were replaced by mosses. Currently, there are about 10 thousand species. The difference between mosses and algae is not only in the habitat. Their life on the ground became possible due to the significant complication of the structure. Most mosses have a leafy structure. At the same time, rhizoids persist in them throughout their lives.

moss structure

How is moss different from algae? In spore plants, a change of generations is observed in the life cycle. Let's analyze this process using the example of their typical representative of moss cuckoo flax. Its sexual generation looks like a green carpet. Visually, it resembles some types of algae.

If you look closely, the green cover consists of individual thin stems with sessile leaves. At the end of summer, a box on a leg forms on their top. This asexual generation is the sporophyte. The shape of the box looks like a cuckoo. Hence the name of this plant species.

Cells of asexual reproduction - spores - mature in the box. When ripe, they fall out into the soil and germinate. From the spores, green leafy shoots grow again. They form organs of sexual reproduction - gametangia. In them, germ cells - eggs and spermatozoa - mature. In the presence of water, they merge, resulting in the formation of a zygote. A sporophyte grows from it. Thus, the sexual generation predominates in the life cycle of bryophytes.

Plant species: algae, mosses

Since algae appeared on the planet much earlier, their structure is much more primitive. This does not allow these plants to master new habitat conditions. To understand how moss differs from algae, it is necessary to consider the features of their organization and life processes.

Let's start with the structure of the body. All mosses are exclusive Among the algae there are various species. For example, chlamydomonas and chlorella are unicellular. Volvox is a colonial algae. It consists of a group of cells united by a single membrane. The thalli of chlorella and spirogyra are more complex. They are all multicellular.

Many differences can be found in the features of the life of these organisms. Both mosses and algae are capable of sexual reproduction. But in the latter, this process occurs under adverse conditions. This is a kind of protection of algae. For example, when the water temperature drops or the reservoir dries up, the mother cell of chlamydomonas forms gametes.

They go out into the water and merge in pairs. As a result, a zygote is formed - a fertilized egg. It is covered with a thick shell, which allows it to endure both freezing and drying. When favorable conditions occur, the contents of the zygote divide, as a result of which mobile cells of asexual reproduction - zoospores - enter the water. They increase in size and take on the features of adults.

So, in our article, we examined how moss differs from algae. The main features are as follows:

• Algae are older plants that originated in water.
• Mosses are the first land-dwellers.
• Algae can be unicellular or multicellular. There are also colonial forms.
• All mosses are multicellular plants, the body of which has a leafy structure.
• In algae, male and female individuals, sporophyte and gametophyte do not differ externally. And mosses can have differences in their structure.
• Algae can reproduce by parts of the thallus. Mosses are not capable of vegetative reproduction.