Euglena green

In nature, Euglena usually live in heavily polluted fresh water bodies with a large amount of dissolved organic matter. Often cause "bloom" of water.

Euglena green combines the characteristics of both plants and animals. Its cell contains chlorophyll and in the light can be fed through the process of photosynthesis, as plants do. In the dark and with an abundance of organic food, euglena feeds heterotrophically, like an animal, absorbing organic matter. In addition to the method of nutrition, it is also related to animals by the ability to actively move.

Euglena green usually lives in polluted fresh waters. With its strong reproduction, the water acquires a green tint (“blooming water”). The cell size is about 0.05 mm, so it is difficult to see the euglena with the naked eye. The body is elongated, at the front end there is one long flagellum, the rear end is slightly widened and pointed. Euglena has an elastic membrane that gives it a shape, but allows you to slightly change the shape of the cell. The movement is carried out in the direction where the flagellum is located. He is screwed into the water, the cell itself at this time spins in the other direction.

In the cell, the flagellum passes into the basal body . It is dense and serves to fasten the flagellum.

On the same side, where the flagellum is located in green euglena, there is a cellular mouth with which it swallows organic particles. The flagellum helps.

Also in the front of the cell is a photosensitive formation - the eye , which has a red color. Euglena green has a positive phototaxis, i.e., floats in the direction of light.

Euglena green is a typical plant flagellate, has a green fusiform, long body, the rear end of which is usually pointed, the flagellum is located on the front obtuse end. The front end has a red eye (photosensitive organoid, stigma ) ^[1] . Body length 50-60 micrometers, width 14-18 micrometers. The shape of the body is mobile: euglena can contract, becoming shorter and wider. Green euglena propagates by longitudinal cell division ^[1] . Upon the occurrence of environmental conditions that are bad for it (winter, drying out of the reservoir), green euglena forms a cyst , while losing the flagellum and becomes spherical ^{[1] [2]} .

Euglena green is capable of autotrophic type of nutrition due to the presence of chloroplasts . Photosynthesis occurs in the light. In the dark, due to its impossibility of euglena, green eats heterotrophically . A long stay in poorly lit places leads to the “discoloration” of the green body of the euglena: chlorophyll in chloroplasts is destroyed, and the euglena becomes pale green or completely discolored. However, when returning to the illuminated places, the euglena again begins to have autotrophic nutrition. Euglena green moves using a flagellum, while moving forward at the end on which it is located ^[1] .

Often in nature, in the warm season, under certain favorable conditions, euglens begin to quickly divide. Then the water in the pond or river backwater, which was still transparent yesterday, becomes dull green or brownish. In a drop of this water under a microscope, you can see a lot of euglena.

The closest relatives of green are ( Euglena sanguinea ) and snow euglena ( Euglena nivalis ). With the mass reproduction of these species, the so-called "snow flowering" is observed. More Aristotle in the IV century BC. e. described the appearance of "bloody" snow. Charles Darwin observed this phenomenon while traveling on a Beagle ship.

On the territory of Russia, “flowering” of snow was repeatedly observed in the Caucasus, the Urals, Kamchatka and on some islands in the Arctic. Flagellates are able to live in snow and ice, as a result of mass reproduction of flagellates, the snow acquires the color that the cytoplasm of these protozoa has. Green, yellow, blue and even black “bloom” of snow is known, but red is more often observed, caused by a large number of euglena breeding - bloody and snowy.

Some euglenaes are generally not capable of photosynthesis and feed heterotrophically like animals, for example, representatives of the genus Astasia ( Astasia ). Such animals can even develop complex oral devices with which they absorb the smallest food particles.