Edible algae. The algae body is hairy, straight or curved, brown, and brown-black after drying, and many algae bodies often form a ball, with the largest diameter of 0.5 meters; The width of a single algae body is 0.3 ~ 0.51mm when dried, and it is sticky and elastic after absorbing water, and its diameter can reach 1.2 mm. The filaments in the algae are straight or curved, and many filaments are arranged almost vertically in parallel in a thick and obviously layered colloid envelope; The sheath of a single algae filament is thin and inconspicuous, and colorless. The cells are spherical or slightly oblong, with a diameter of 4 ~ 5 (~ 6) microns, and the contents are blue-green. Heteromorphic cells are terminal or metaplastic, spherical and 5 ~ 6 (~ 7) microns in diameter.
Nostoc flagelliforme is widely produced in arid and semi-arid areas of Inner Mongolia Autonomous Region, Ningxia Hui Autonomous Region and Gansu, Qinghai and Shaanxi provinces in China, and it grows more in areas with annual rainfall of 80 ~ 250 mm and tertiary red soil as its parent material. The Soviet Union, the Mongolian People's Republic of China, Czechoslovakia, France, the United States, Mexico, Morocco, Somalia and Algeria also have them. Nostoc flagelliforme is a traditional non-staple food in China, especially in the south.
Nostoc flagelliforme is a kind of terrestrial cyanobacteria, whose scientific name is Nostoc flagelliforme. It belongs to Nostoc genus of Nostoc family, and it is a filamentous cyanobacteria with heteromorphic cells, which usually congregates in groups. If a shredded Nostoc flagelliforme is soaked in water for a few minutes, it can be observed by optical microscope that it contains dozens to hundreds of filaments. They are surrounded by brown gelatinous substances, and the filaments are also filled with gelatinous substances. It can also be seen by electron microscope that in addition to cyanobacteria, there are bacteria * * * living together.
Nostoc flagelliforme is mainly distributed in arid desert grassland. Nostoc flagelliforme is found in Ningxia, Gansu, Qinghai, Inner Mongolia and northern Hebei. In the world, besides China, Nostoc flagelliforme grows in Russia, France, Nigeria and other countries.
Nostoc flagelliforme is a photosynthetic prokaryote that can fix nitrogen. There are mainly two kinds of cells in its filamentous body: one is vegetative cell, which is green and carries out photosynthesis-absorbing, releasing and synthesizing organic substances; The other is idioblast, which has a larger volume, thicker cell wall and lighter color. It mainly performs nitrogen fixation-reducing nitrogen in the air to ammonia and synthesizing amino acids. Because Nostoc flagelliforme can synthesize organic carbon and organic nitrogen from inorganic carbon and inorganic nitrogen, it is of great significance to improve desert soil and reproduce other organisms. Nostoc flagelliforme is known as "the pioneer of developing desert". As Nostoc flagelliforme is an important export commodity, predatory harvesting of Nostoc flagelliforme in northwest and north China every year has seriously damaged the local ecological environment and caused serious consequences. For decades, Chinese scientific and technological workers have made some progress in artificial cultivation and breeding experiments.
The reason why collecting Nostoc flagelliforme will cause such serious damage is that Nostoc flagelliforme only grows in areas prone to desertification, and its tendrils are often intertwined with vegetation roots that can fix soil. Instead of pulling out Nostoc flagelliforme one by one, people uproot all the plants in sight and classify them later. This makes the land soft, and when the wind strengthens, the sand flies with the wind to form sandstorms.