Order Green algae: a brief description

To date, green algae is considered the most extensive group, which has about 20 thousand species. This includes both unicellular organisms, as well as colonial forms, as well as plants with multicellular tallomas. There are representatives who live in water (sea and fresh), as well as organisms adapted to survival on land in conditions of high humidity.

Department of Green algae: a brief description

The main distinguishing feature of the representatives of this group is their coloring - for all species a green or green-yellow color is characteristic. This is due to the main pigment of cells - chlorophyll.

As already mentioned, the department unites completely different representatives. There are unicellular and colonial forms, as well as multicellular organisms with a large, differentiated thallus. Some unicellular representatives move with flagella, multicellular, as a rule, are attached to the bottom or inhabit the water column.

Although there are organisms with bare cells, most representatives have a cell wall. The main structural component of the cell membrane is cellulose, which, by the way, is considered an important systematic characteristic.

The number, size and shape of chloroplasts in the cell may vary depending on the plant species. The main pigment is chlorophyll, in particular, a and b forms. As for carotenoids, plastids contain mainly beta-carotene and lutein, as well as small amounts of neosanthine, zeaxanthin and violaxanthin. It is interesting that the cells of some organisms have an intense yellow or even orange coloration - this is due to the accumulation of carotenes outside the chloroplast.

Some unicellular green algae have a specific structure - an eye that reacts to the light of the blue and green spectrum.

The main storing product is starch, the granules of which are mainly contained in plastids. Only in some representatives of the detachment reserve substances are deposited in the cytoplasm.

Department of Green Algae: ways of reproduction

In fact, representatives of this detachment are characterized by practically all possible methods of reproduction. Vegetative reproduction can occur by dividing the cell (unicellular representatives without the cell wall), fragmentation of the thallus (this method is characteristic of multicellular and colonial forms). In some species specific nodules are formed.

Asexual reproduction is represented by the following forms:

• Zoospores - cells with flagella, capable of active movement;
• Aplanospores - such spores do not have a flagellar apparatus, but contractile vacuoles are well developed; Cells are not capable of active movement;
• Autospores - this type of dispute is primarily associated with adaptation to the external environment. In this form, the organism can wait dry and other unfavorable conditions.

Sexual reproduction can also be diverse - it is oogamy, and heterogamy, and hologamy, as well as isogamy and conjugation.

Order Green algae: a characteristic of some representatives

This group includes many famous representatives of the plant world. For example, unicellular algae spirogir and chlorella are also included in the detachment.

Chlamydomonas is a fairly famous genus of green algae, which is of great practical importance. This group includes unicellular organisms with a red eye and a large chromatophor, which contains pigments. It is the chlamydomonas that causes "flowering" of water bodies, puddles and aquariums. In the presence of sunlight, organic substances are produced by photosynthesis. But this organism can absorb substances from the external environment. Therefore, chlamydomonas are often used to purify water.