Silver fungus is also known as white fungus, snow fungus, chrysanthemum ear and so on. It is named for its silvery white color and ear-like shape (Figure 4-27). Its son entity milky white to white color, gelatinous translucent, crown-shaped or chrysanthemum-shaped, crisp texture, fragrant and refreshing, often eaten as soup or cold, color and lustre, clean and elegant, both nutritious, but also attractive to the appetite, is one of our country's traditional and popular food and medicine dual-use mushrooms. It is a traditional and popular dual-use fungus for food and medicine in China. Its nutritional and environmental requirements are as follows:

Figure 4-27 Ginkgo Fungus

(1) Nutrition

Ginkgo Fungus is a wood-rotting fungus, which belongs to heterotrophic type organisms. Ginkgo can only directly utilize small molecule carbohydrates with simple structure, such as monosaccharides (glucose), disaccharides (sucrose), etc., and it is difficult to utilize large molecule carbohydrates with complex structure, such as cellulose, hemicellulose, lignin, etc., which need to be decomposed by companion fungus, Amanita pallidiflora into small molecule carbohydrates, in order to be ginkgo mycelium Absorption and utilization. Therefore, when making psyllid strains, add a certain amount of glucose and sucrose in the culture medium, which can promote the growth of mycelium, and the amount of sugar used in the culture medium of the strain is 1% to 2%, and the amount of sugar used in the actual production of the culture material is 0.2% to 1.5%. Cottonseed hulls, wood chips, bagasse, corn cobs, soybean stalks, peanut shells, etc., all contain a large amount of cellulose and lignin, which is the main source of carbon nutrients, and thus is used as the main culture material for artificial surrogate cultivation. In artificial cultivation of silver fungus, commonly used bran, rice bran, soybean meal, urea, etc. as a nitrogen source. As urea is processed at high temperature, it produces substances that are harmful to the mycelium of silver fungus. Therefore, if it is necessary to add urea in cultivation, its concentration is controlled at 0.1% to 0.2%.

Inorganic salts are indispensable substances in the life activities of psyllids, some of which are involved in cellular components, some as components of enzymes, some involved in energy metabolism, some controlling the state of protoplasmic colloid, and some involved in the maintenance of cellular osmotic properties. Adding appropriate amount of gypsum powder, magnesium sulfate, calcium superphosphate and potassium dihydrogen phosphate in the culture material helps the growth and development of mycelium and substrate.

(2) Moisture and humidity

The moisture content of fresh ginkgo is 85% to 95%. Most of the moisture required for the growth and development of the fungus comes from the culture material, and when cultivated on behalf of the material, the moisture content of the culture medium is 50% to 55% is appropriate. Too little water, mycelium growth is hindered, the ear is not normal; too much water, mycelium respiratory difficulties, resulting in mycelium death, causing the breeding of stray bacteria. Substrate protoplast formation stage (i.e., expanding the mouth to increase oxygenation period), the relative humidity of the air in the ear room should be maintained between 85% and 90%, the humidity is too low, it will cause the inoculation block dry and make the white hair mass can not be formed, affecting the ear. Substrate development stage, humidity should be maintained between 85% to 95%, low relative humidity, so that the substrate dry shrinkage and stop growing; humidity is too high easily caused by contamination of stray bacteria, rotten ears and so on.

(3) temperature

Silver fungus is a mesophilic fungus, mycelium (a mixture of silver fungus and ash mycelium) can grow within 6 to 32 ℃, optimal 24 to 26 ℃. 12 ℃ or more, with the rise in temperature growth accelerated to 35 ℃ to stop growing. Substrate in 18 ~ 28 ℃ can grow and develop, the most suitable 22 ~ 24 ℃, this time the sub-strategy growth, flower shape, ear piece thick, high yield. Cultivation temperature for a long time higher than 25 ℃, inoculation hole mouth of the white hair mass secretion of yellow water droplets; higher than 28 ℃ will appear black water droplets, and the base of the black, affecting the ear; for a long time lower than 20 ℃, is not conducive to the growth of the substrate. Fragrant gray mycelium grows within 6 to 38 ℃, suitable for 20 to 28 ℃.

(4) ventilation

The growth and development of psyllid requires sufficient oxygen. From spore germination, mycelial growth, the formation of the protoplast to the maturity of the substrate, the demand for oxygen gradually increases. Especially in the stage of formation and opening of fruiting bodies, the demand for air is higher. Under hypoxic conditions, mycelium growth is slow, the substrate of the original base of the late differentiation, twisting and knotting group show not open piece, color yellow quality is poor, but also often easy to cause rotten ears and contamination of stray bacteria.

(5) light

Mycelium growth stage does not require light. Diffused light can be conducive to promoting spore germination and differentiation and development of the substrate, and grow out of the substrate color white, high quality. Strong direct light is not conducive to the development of the substrate; under dark conditions, the substrate is slow to differentiate and turn yellow; complete darkness, the substrate is difficult to form.

(6) pH

Mixed mycelium in the wood chip medium, pH 4.5 ~ 7.5 range can grow, but to pH 5.5 ~ 6.5 for the most suitable. pH lower than 4.5 or higher than 7.5 are not conducive to the growth and development of silver fungus. When preparing the medium, the pH should be higher than the optimal pH.

(7) Biological factors

The pure mycelium of silver fungus has almost no ability to decompose cellulose, lignin and starch, so it must be accompanied by the scented ash mycelium (feathery mycelium) when cultivating silver fungus in the natural conditions or artificial cultivation of the substitute material. Bag planting silver ear, you can see the translucent plastic bag with black pattern, but also appeared copper-green or grass-green powder, which is the powder is the spores of the fragrant gray fungus. Fusarium aromatic ash bacteria can be difficult to use the complex structure of the large molecular carbohydrates of the silver fungus mycelium, decomposition of simple structure of the silver fungus mycelium can be utilized by the small molecule carbohydrates. This facilitates the germination of psyllid spores, the colonization and growth of mycelium and the differentiation and development of the fruiting body to complete its life history. The current artificially cultivated strain of silver ear is a mixture of pure white mycelium of silver ear and fragrant gray mycelium.