Cyanobacteria have no organelles such as chloroplasts, mitochondria, Golgi apparatus, centrosomes, endoplasmic reticulum and vacuoles, but they contain chlorophyll a, chlorophyll b, several xanthophylls and carotene, and phycobiliproteins (phycoerythrin, phycocyanin and allophycocyanin). Generally speaking, cells containing chlorophyll a and phycocyanin are mostly blue-green. Similarly, there are a few species that contain more phycoerythrin, and the algae are mostly red. For example, a blue-green algae born in the Red Sea is called Chaetomium rubrum. Because it contains a lot of phycoerythrin, the algae are red and reproduce quickly, so the seawater is also red, hence the name Red Sea. Although cyanobacteria have no chloroplasts, there are many photosynthetic membranes in the cytoplasm, called thylakoids, to which various photosynthetic pigments are attached, and the photosynthesis process is carried out here. The cell wall of cyanobacteria is similar to bacteria in chemical composition, mainly peptidoglycan (a compound formed by sugar and polypeptide); The stored photosynthetic products are mainly cyanobacteria starch and cyanobacteria particles. The cell wall is divided into two layers, the inner layer is cellulose, and a few people think it is pectin and hemicellulose. The outer layer is a colloid sheath, mainly pectin or a small amount of cellulose. The inner wall can continue to secrete colloid and increase into the rubber sheath. Some kinds of rubber sheaths are densely layered, and some kinds of rubber sheaths are easy to hydrate, and the rubber sheaths of adjacent units can be fused with each other. There may be non-photosynthetic pigments such as brown, red and gray in the rubber sheath. Cyanobacteria have single cells, colonies and filaments. The simplest is a single cell. Some unicellular organisms become groups because the daughter cells are embedded in the gelatinized mother cell wall after cell division. If they divide repeatedly, there will be many cells in the group, and the larger group can be divided into several smaller groups. Some single-celled organisms are polarized at the bottom and top because of their attachment to life. Filaments are formed by repeated division of cells along the same division plane and connection of daughter cells. Some filaments have the same cells, some filaments have idioblast differentiation, some filaments have false branches or true branches, and some filaments have apical cells that gradually taper into trichomes, which is also called polar differentiation. Filaments can also be connected into a group and wrapped in the colloid sheath of the male, which is a group of multicellular individuals.

There are two ways to reproduce cyanobacteria. One is vegetative propagation, which includes direct cell division (fission), population division and the production of filamentous algae fragments. The other is that some cyanobacteria can produce endospore or ectospores.

Propagation of cyanobacteria

To reproduce asexually. Spores have no flagella. At present, cyanobacteria have not been found to have real sexual reproduction.

Cyanobacteria is the earliest photosynthetic oxygen-releasing organism, which has played a great role in transforming the earth's surface from anaerobic atmospheric environment to aerobic environment. Many cyanobacteria (such as ANABAENA) can directly fix nitrogen in the atmosphere (reason: it contains nitrogenase, which can directly carry out biological nitrogen fixation) to improve soil fertility and increase crop yield. There are also edible cyanobacteria, such as famous Nostoc flagelliforme and Nostoc commune (Nostoc commune) and Spirulina.