Plune clavate: life cycle, structure and reproduction

Plawn clavate (Latin Lycopodium clavatum) occurs in pine and mixed forests. Thin evergreen herbaceous shoots are crowned with dense spikelets. But this is not inflorescence, because the plown is the highest spore plant and never blooms. Reproduction and life cycle have peculiar features associated with the ancient origin of the whole group. It is characterized by a number of features and the structure of the clown planon.

Living fossils

In the Paleozoic era, woods from tree-like horsetails, plains and ferns covered huge spaces on the planet. Over time, these groups of organisms, for the reproduction of which water is needed in drip-liquid form, gave way to more adapted plants - gymnosperm and flowering plants. Not survived in this struggle for the existence of tree-shaped plains - lepidodendron and sigillaria, reaching a height of 40 m. But it was they who gave rise to powerful coal seams in some regions of the planet. Modern plants of the Plaunov family are not similar in appearance to the lush carbonaceous vegetation, but they inherited the method of reproduction and the cycle of development of their ancient ancestors.

Why is the plant called "plaun"?

From the original place of attachment of one of the stages in the life cycle of the placenta - sprouting - creeping green stems begin to grow. On the perimeter they are still young, without sporiferous spikelets, and in the central ring - obsolete. It seems that the clown-shaped plains move through the forest. This is due to the constant withering away of old shoots and the growth of new ones. The peculiarity of the Slavic peoples was noticed long ago and gave the name "plune" (quicksand) to the "floating" plant. The origin of the Latin denomination of the genus of the plains is of interest. It is related to the German word "wolf's paw". So in ancient times, the plown was called in Germany. In the XVI century, the word was translated into Latin, it turned out as a result of Licopodium. Different peoples call the planet "lycopodium", "tree."

Features of the plains

Peculiar and very ancient plants are found in the forest zone of the Northern and Southern Hemispheres. The genus Lycopodium, to which the clown-shaped plown belongs, existed in the forests of the Paleozoic over 350 million years ago. Many signs indicate that this group is gradually dying out. But in the structure of the plains there are features of a higher organization than mosses. You can get acquainted with them using the example of a clown-shaped planet.

The most ancient signs:

• Dichotomous branching;
• Spiral leaf arrangement.

Features of higher plants in the plauna:

• Differentiated tissues;
• Herbaceous stems;
• Real roots.

A characteristic feature is microphilia associated with the origin of leaves from superficial stem caulis.

The structure of the clown planon

All the perennial plant (asexual stage) looks fluffy from the set of deviating small leaves. They have a linear-lanceolate shape, each ending in a white, extremely brittle hair. Plawn clavate has a long and thin creeping stem. This peculiar live cord reaches a length of 1 to 4 m. From it originate lateral ascending shoots (50 cm). There is no stern root, only the accessory ones, with which the plant is attached to the ground. Long thin legs with sparsely located leaves lead from the stem to the thickening on the top of the shoot. These are spore-bearing spikelets that have a cylindrical shape and reach a length of 4 cm. Usually two groups are collected, and groups of three or four are less common. Sporangia are located in the axils of sporelogy. Each of these bags is filled with small disputes.

The structure of the gametophyte

Spores of the clown planon give rise to a gametophyte, or sprouting. The structure of the clown-shaped planet at this stage is completely different from the perennial plant, as we are accustomed to seeing it. Sporophyte reaches a little more than one millimeter in diameter. This adolescence is a temporary phenomenon in the life of a plant, but it is very necessary. If disputes are in adverse conditions, then they can not give rise to a new organism for a long time. Self-absorbing nutrients microscopic gametophyte can not, he uses the "services" of soil fungi. If spores quickly germinate on the surface, then the translucent bud acquires a pale green color and is capable of photosynthesis. Under favorable conditions, the gametophyte ripens faster. Sexual gametes appear in special formations. Female - ovum - large and immovable. Male - sperm - small, equipped with flagella and quickly moving. Ripen cells mature at different times. Male cells to move to eggs need water droplets. When the gametes merge, fertilization takes place. Zygote begins to divide, giving rise to the cells and tissues of the future sporophyte.

Life cycle of a clown planon

We trace the development of the plant from the spores to the adult plant. It is it we usually see in the forest or in the photo "Plune clavate". In the sporangia sporangia of the spikelets, a large number of spores resemble a yellow powder in the summer. Consider the structure of dust particles only under a microscope. Chemical analyzes indicate a significant content of vegetable fat in them. Spores emerge in July-August, are carried by the wind through the forest and serve the spread of the planet. In the soil, under favorable conditions, germination begins. A gametophyte is formed, resembling a small pea with a tail. Sexual multiplication of clavate plauna is an intermediate stage in the life cycle that provides genetic diversity. After the formation of gametes and fertilization, microscopic sporophyte appears on the sprouting. In its structure it is already possible to consider a thin green stem and leaves. Escape rushes to the light, and the root - down, into the soil. More often the plown breeds in a vegetative way - each of its whip, having roots, is able to survive without a mother plant.

Practical use of the

For medical purposes, spores of a plant known as Lycopodium are used. Used raw materials collected in natural conditions, for the preparation of baby powder and anti-decubitus. Lycopodium contains:

• butter;
• Proteins;
• Polysaccharides;
• Sitosterol;
• Phenol carboxylic acid;
• minerals.

Folk healers appreciate wound-healing abilities of lycopodium, recommended for burns, frostbite. The herb has anti-inflammatory properties and is used for diseases of various organs and systems. External forms of drugs from the spores of the placenta help with eczema, furuncles, lichen. Treatment with the preparations of the planet should be done on the recommendation and under the supervision of a doctor.

Environmental requirements

The stems of the planet gradually "sprawl" away from the original place of spore germination. The ability to their formation in the plant appears on the 15-30th year of life. The spleen dies at the stage of shoots and roots formation. Features of the structure of clavate and its reproduction predetermined the location of the plant. Undemanding to the soil, it needs water droplets for fertilization at the sexual stage. Such conditions are found in many regions and countries, including Russia, Belarus, Ukraine. The plant is found mainly on sandy soils in light pine forests. Less often - in mixed and deciduous. In the last half-century, the number of the planet has decreased significantly. One of the problems of renewal of the range is associated with the slow formation of sporiferous spikelets. In the forests, vegetative shoots can be found much more often than generative shoots. In addition, there are not always suitable conditions for sprouting spores. They may die from drying out or for years not give rise to a gametophyte. This is only part of the environmental issues associated with the oldest plant on earth. It can repeat the fate of neighbors around the planet in the distant Paleozoic - lepidodendron and sigillaria.

The reduction of forests, their transformation into agricultural landscapes adversely affected the sexual and asexual reproduction of the clavate plauna. It is being protected in a number of US states, where the plant is recognized as rare, requiring protection.