Life history and economic value of laver.

A: ① Life history of laver: It belongs to the type of heterogenic alternation. Monoecious, it produces sex organs, seminal vesicles and fruit cells at a suitable temperature, and there are 1 egg in the fruit cells. After the sperm in seminal vesicle is released, it floats on the fertilized silk of the fruit cell with the water flow, enters the fruit cell and combines with the matrix to form a zygote. The zygote undergoes mitosis and common division to form 8 (2n) fruit spores. When the fruiting spores are mature, they fall on the shells of meretrix meretrix, oyster or other mollusks, and germinate and grow into a single branched filament, namely Phaeocystis (2n). Shell spores are produced by meiosis of Chlamydomonas. Porphyra haitanensis can be directly developed when the water temperature is about 65438 05℃. In summer, due to the high water temperature, shell spores develop into Porphyra haitanensis, Porphyra haitanensis produces monospores, monospores develop into Porphyra haitanensis, and so on, until the water temperature is about 65438 05℃ in late autumn, monospores and Porphyra haitanensis develop into Porphyra haitanensis at the same time.

② Economic value: Porphyra is a delicious food with high protein content. Has the effects of lowering cholesterol and preventing arteriosclerosis.