Jiuzhai Polyporus

Jiuzhai Polyporus

Jiuzhai Polyporus is a protected geographical indication product.

　　Jiuzhai Polyporus, a type of traditional Chinese medicinal polyporus fungus, gets its name from its origin in Jiuzhaigou. It mainly grows in high-altitude mountainous shaded areas at elevations of 2,000 to 2,900 meters. The growth soil is primarily mountain humus soil with high organic matter content. The low temperature and large diurnal temperature variations allow Armillaria mellea sufficient time to absorb nutrients from the host trees for development. Wild products are mostly subspherical in shape, larger in size, lower in density, with a polysaccharide content of 5% and ash content ≤11%. Due to their resemblance to horse dung, they are also commonly known as "horse dung polyporus" or "horse dung Jiuzhai Polyporus," considered to be of upper-medium quality among polyporus fungi. These are traditional export medicinal herbs. Their shape is subspherical, and the outer skin color is black. Cultivated Jiuzhai Polyporus tends to be larger in size, appearing as elongated blocks or irregularly shaped spheres, slightly flattened, with some branching resembling ginger shapes. The outer skin color is darker than that of wild Jiuzhai Polyporus, and certain physicochemical indicators are superior to those of the wild variety.

　　Polyporus is a type of low-temperature parasitic fungus. It occurs when Armillaria mellea (Vahl:Fr.) Karst. invades the sclerotium of Grifola umbellata (Pers.:Fr.) Pilát, activating the polyporus fungus's innate immune response to foreign invasion. The mycelial cells of the polyporus fungus lignify, forming an isolation chamber with a structure similar to the outer layer of the sclerotium, enclosing the hyphae of Armillaria mellea and parts of the polyporus mycelium. Within the isolation chamber, the Armillaria mellea digests the enclosed polyporus mycelium, while the polyporus mycelium can also invade or attach to the hyphae of Armillaria mellea and the cell gaps of the infected zones to absorb their metabolic byproducts. This allows the polyporus sclerotium to sprout new polypori and grow normally. When the polyporus mycelium within the isolation chamber is digested, the vitality of the Armillaria mellea also weakens. After disintegration, it is absorbed and utilized by the polyporus fungus, and the isolation chamber becomes a hollow cavity.

　　The unique growing environment results in Jiuzhai Polyporus being larger in size, lower in density, and having higher contents of polysaccharides and ergosterol, but lower ash content compared to ordinary polyporus. In appearance, wild Jiuzhai Polyporus is mostly subspherical, cultivated varieties appear as elongated blocks or irregular spheres, whereas other types of polyporus are mostly flat and strip-shaped with smaller individual sizes (commonly referred to as "chicken dung polyporus").