Life cycle of mosses: sequence of stages

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

What is moss?

Mosses is a group of ancient organisms. According to some assumptions, they are the ancestors of the now existing terrestrial plants. The water on our planet is the source of life, in which everything alive, including plants, originated. About 420 million years ago, the descendants of green algae began to develop land.

Most clearly, such mechanisms of adaptation can be traced in mosses. For example, the main condition for the successful reproduction of algae is the presence of water. Mosses can also multiply only with the help of moisture.

The life cycle of mosses is very interesting. Of the whole group of higher plants, they are the most primitive organisms. Bryophyta or moss-like are multicellular plants, practically devoid of conductive tissue. Therefore, the size of these living organisms is very small - from 1 mm to 50 cm. The mosses do not have roots; they attach to the surface of the earth with filiform outgrowths, rhizoids, by which these plants suck up water. Rizoids consist, at times, from one cell. In contrast to the roots of all other plants that have a multicellular conducting tissue. Other parts of the moss body can be conditionally defined as the stem and leaves. However, in fact, they are completely unlike 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 variety of temperature and climatic conditions and are distributed almost throughout the entire planet: from the polar regions to the tropics. They perfectly exist in conditions of high humidity of air - in forests, mountains. Moss is also found in arid regions. Survival of bryophytes is striking - they can withstand the effect of a very high temperature, up to 70 degrees Celsius. In a dry climate mosses have adapted to fall into a state of suspended animation, associated with seasonal climatic fluctuations. When the rain falls and the air temperature decreases, the soil becomes moist, and the moss "comes to life", the breeding cycle begins. Let us consider the value of spores in the life cycle of mosses.

Conditions of life of mosses

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

The only place where mosses can not exist is saline soils near the sea.

Extremely tenacious disputes mosses. With the wind they can travel great distances. The viability of the spores persists for dozens of years.

Mosses accumulate significant moisture reserves, so with their help there is a regulation of the water balance of a particular landscape. Therefore, moss is extremely important for the ecosystem. In addition, for some species of moss, moss is the main fodder base.

On the earth today grows about 30 thousand species of mosses. Scientists classify these plants according to morphology, the structure of spore bolls and ways of spreading spores.

Mosses can reproduce both by spore and vegetatively. In the life cycle of moss, a generation of sex over asexuals predominates.

Deciduous mosses or bryopsids

This is a fairly large class of plants, which is represented by 15 thousand moss species. They are extremely diverse in appearance, size and shape. This plant is a stem covered with leaves, which are spirally located around the stem. The most vital stage of their development is called gametophyte. The method of reproduction of deciduous mosses is spores. Most often, these plants are found in wet places, in marshes, as well as in the tundra. Kukushkin flax and sphagnum are typical representatives of briopsides.

Hepatic Mosses

Liverworts are represented by two subclasses: the Jungermannian and the Marshant. 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. Method of reproduction - spores, which are spread with the help of a special device, this sort of "spring", which is called the elater. These plants are well established in a humid tropical and temperate climate. Among the representatives - polymorphic march, cilia, ciliate, blepharostroma, and others.

Anthocerotic mosses

This class is not so numerous and is represented by 300 plant species. Sporophyte - the most important life stage in the cycle of development of this plant. Antocerotic mosses look like a thallus - this is a body that does not dissect into root, stem and leaves. Such mosses grow in moist rainforests and temperate climate zones. Antoceros is a typical representative of this class.

The life cycle of cuckoo flax will be described below. Moss Kukushkin flax is a perennial plant. Its structure is a sufficiently developed structure. The primary horizontal stem is brown without leaves and the secondary stem is straight, branched or single.

The secondary stem is covered with dark green harsh, like an awl, leaflets. 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 are able to reach a length of almost 40 cm.

Places of growth of moss of cuckoo's flax

Kukushkin flax usually grows well in wet places, on marshes, damp meadows and in fir groves, loves sunlight. In open areas it grows very powerful, capturing all new territories. Its stems are so tightly "envelop" the soil that the seeds of other plants can not germinate. This plant is chosen by forest felling or fires. This moss absorbs water very well. Density of the plant retains moisture in the soil. Due to what is bogging terrain.

People have long used this plant as a heater. Konopatyat with its help the walls of log houses. Sometimes used as a medicinal plant for colds.

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

Life cycle of moss of cuckoo's flax

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

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

Now it is understandable why in the life cycle of mosses a generation of sex over asexuals predominates.

Boxes with spores, as people say, look like a cuckoo sitting on a pole. In general, the moss of Kukushkin flax resembles a miniature flax plant, from where it got its name. Thin hairs on the cap, which covers the box with spores, are also similar to linen yarn.

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

Stages of the life cycle of moss

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

When a haploid spore enters the moist soil, it begins to germinate, forming a protoneme - a filamentous adolescent. It forms a gametophyte - female or male.

At the tops of different stalk-gametophytes of cuckoo's flax develop antheridia and archegonia - male and female genital organs. In archegonium, oocytes mature, and in antheridia - two-spermatozoa. Externally, male plants are distinguished by large leaves of a yellowish-brown color on the top. In female plants, such leaves are absent.

For successful fertilization, drops of moisture are needed, which transfer spermatozoa from antheridia to archegonia, where the eggs are. This process is usually promoted by rain or strong dew.

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

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

Structure of moss of cuckoo's flax

The body of mosses is similar in structure to algae, since it also consists of thalli. Nevertheless, it can have a structure resembling stems and leaves. To the soil it is attached with the help of rhizoids. These plants are able to absorb water and minerals not only directly by the rhizoids, but also the entire body.

The value of moss in nature

In general, mosses are an important component of the ecological system of our planet. The life cycle of mosses differs from the cycle of other higher plants. They well survive on nutrient-poor soils. Populate those places that were subjected to adverse human impact. Thus, preparing the land for restoration. In fact, when it mends, moss forms a useful soil substrate, on which other plants will subsequently grow.

Mosses are indicators of pollution of the environment, in particular, of the atmosphere. As some moss species do not grow in places where the concentration of sulfur dioxide is exceeded in the air. Due to the lack of certain types of moss in traditional habitats, one can also judge the pollution of the atmosphere. However, also mosses indicate changes in soils, and much more.

Mosses preserve a delicate balance in permafrost areas, covering the soil from sunlight. Maintaining, thus, the ecological balance.

Now, if you are asked: "Describe the life cycle of moss," then you can easily do it.