floating fern Salvinia - small, floating on the surface of bodies of water plant belonging to the family Salvinievyh.This type species of the genus Salvinia - the only growing on the territory of the Russian Federation.The plant is often cultivated as an aquarium.
Salvini floating: the structure and appearance
fern is an annual with a thin stem, reaching fifteen centimeters in length and having at each node whorl of three leaves.Stem floating on the water surface.Two of his whole sheet are ovate-elliptical shape and slightly heart-shaped base.They are topped with warts, which are at the tips contain a bundle of thick short hairs.The lower surface of the leaves has a dense cover of brown hair, retaining the air bubbles.This enables Salvinia retained on the surface of the water.The third list is underwater, cut into hairy whiskers and share very similar in appearance to the roots.In fact, it just serves as a root: suck water and nutrients, and also stabilizes the fern.
Lifecycle Salvinia floating
At the base of the leaves under the water, there are clusters of four to eight sori spherical.Some of them contain macro- and microsporangia and later they form male and female gametophytes.Each megasporangiya formed four megaspores, but develops only one of them.Typically, in one form microsporangia sixty four microspores.
tend to fall sori fall and sink to the bottom of the pond.There they spend the winter and in the spring there is a destruction of their shell.Sporangia float on the water surface and germinate.After breaking the wall of sporangia form microspores trehkletochny male gametophyte, and then two of its cells are formed two spermatogenic cells and two fruitless.Of these four, each producing sperm.Germinate megaspores also breaks the shell to form a female gametophyte.It formed three archegonium but develops after fertilization, only one of them.
area of ​​distribution
Salvini floating a fairly wide range: it is common in the waters of Africa, temperate and tropical regions of Asia, as well as in southern and central Europe.On the territory of the Russian Federation, the fern is mainly found in the south of the European part of the Far East, in western Siberia.Salvini floating prevalent in water bodies with slow flowing or stagnant water, very often it can be seen in the large Russian oxbow rivers.
Application and value
on the surface of ponds this fern, as well as other kinds of Salvini, forms dense thickets that cover the access of light to the water body, which often leads to significant changes in the water environmental conditions.As a result, in many states Salvinia floating plant is considered harmful.However, there is at this fern and useful properties: for example, its thickets provide excellent refuge for the fish fry.
As previously mentioned, Salvinia floating cultivated as aquarium plants.However, it bred not only as a decorative element of the container, which contains the fish, but also as a good natural shade for other plants that prefer diffused light.
Content fern
best to put Salvini floating in the warm temperate or tropical aquariums.By the terms of the content of the special requirements of the plant does not show.It does not matter any hardness or acidity - in soft and hard water fern grows equally well.The temperature in the tank should be maintained at at least 24 degrees.If the water is warmed only to 20 degrees, plant growth slows down (the leaves become smaller), but did not stop completely.
If your tank has a floating Salvinia, regularly replace the water.As an instrument of artificial lighting is recommended fitolampy tank with capacity of three watts per liter, and fluorescent lamps.If you are using incandescent bulbs, then make sure that their power was small, otherwise you can retain moisture air.
