Detailed Explanation of Key Techniques for High-Yield Cultivation of Lingzhi (Reishi)

Lingzhi (Reishi), also known as Wannianxun, Chizhi, Mulingzhi, Lingzhicao, Sanxiu, etc. Its fruiting bodies and spores are used medicinally, with effects of nourishing, strengthening, invigorating the brain, promoting digestion, reducing inflammation, and promoting diuresis. It is mainly used to treat chronic bronchitis, coronary heart disease, neurasthenia, insomnia, acute and chronic hepatitis, leukopenia, atrophy with extreme rigidity, hypertension, myocarditis, rheumatoid arthritis, sequelae of cerebral concussion, migraine, pneumosilicosis, impotence, spermatorrhea, lumbar soreness, tinnitus, and other conditions. Main producing areas include Jilin, Hebei, Shanxi, Shandong, Shaanxi, Anhui, Zhejiang, Fujian, and other provinces.

Morphological characteristics: It is a plant of the genus Ganoderma in the family Ganodermataceae. It is composed of two main parts: mycelium and fruiting body. The hyphae are colorless and transparent, septate, branched, white or brown, 1-3 micrometers in diameter. The mycelium is white and fluffy. The fruiting body consists of the cap, stipe, and hymenium. The cap is semicircular or kidney-shaped, 4-12 cm × 3-20 cm, 0.5-2 cm thick, corky, yellow, gradually becoming reddish-brown, with a glossy crust, annular ridges, and radial wrinkles. The stipe is lateral, rarely eccentric, dark reddish-brown or purplish-brown. The context is nearly white to light brown, and the tubes are 0.2-1 cm long, nearly white, later becoming light brown. The tube mouths are white at first and brown later. Spores are reddish-brown, oval, truncate at one end, with a smooth exospore wall, a rough endospore wall, and containing 1 large oil droplet in the center.

I. Growth habits: Lingzhi is a high-temperature saprophytic fungus. The suitable temperature for mycelial growth is 24-30°C. The suitable temperature for fruiting body growth is 24-28°C. It requires a certain amount of scattered light; spore germination and mycelial growth do not require light, and it is phototropic and aerobic. The relative air humidity requirement is 85-95%. Lingzhi prefers slightly acidic conditions, and the suitable pH of the culture medium is 4-6.

II. Spawn production:

1. Mother culture medium formula and preparation. Potato (peeled) 200 g, glucose 20 g, agar 20 g, monopotassium phosphate 3 g, magnesium sulfate 1.5 g, vitamin B1 1-2 tablets, water 1000 g. During preparation, first cut the potato into thin slices, put them into 1000 g of water and boil for half an hour, filter through double-layer gauze to remove the residue and obtain the filtrate, then add agar to the filtrate and boil while stirring to dissolve it. After dissolving, add glucose, monopotassium phosphate, magnesium sulfate, and vitamin B1 tablets, and make up the water to 1000 mL. This forms the liquid culture medium. Then, while the liquid medium is hot, dispense it into test tubes, with the amount filling one quarter of the test tube length. Plug the test tube mouth with cotton, wrap the top with double-layer kraft paper, and place it in an autoclave for sterilization. During sterilization, first put an appropriate amount of water in the interlayer, then place the test tubes filled with medium into the pot, cover tightly and heat: first exhaust the cold air, then close the exhaust valve and heat to raise the pressure. When the pressure reaches 1.1 kg/cm2 and the temperature in the pot is 121°C, maintain for 30 minutes to achieve the sterilization effect. Stop heating, slowly open the exhaust valve, and when the pressure gauge pointer drops to zero, take out the test tubes, place them on a slant while hot, and after cooling and solidifying, they become slant culture medium.

2. Isolation of pure spawn: there are tissue isolation method and spore isolation method.

Tissue isolation method: Under sterile conditions, select fresh mature Lingzhi, and cut a piece of tissue the size of a soybean seed from inside the cap or stipe. Inoculate it onto the slant medium. Then place it indoors at 24-26°C for 7-10 days. When white mycelium covers the slant, the mother culture is obtained. Then transfer the mother culture to tubes for expansion culture to produce stock spawn and cultivation spawn, and then Lingzhi production can be carried out.

Spore isolation method: Under sterile conditions, take fresh mature Lingzhi and place it on the liquid culture medium (with agar removed from the above formula) and culture statically at 24-26°C. After a certain period, an analogue similar to the fruiting body but with smaller individuals forms on the surface of the medium, or fungal tubes form near the tube wall, and spore powder is released from the tube mouths, thus obtaining pure spores. Then inoculate them on the culture medium to obtain a layer of moss-like vegetative mycelium.

III. Lingzhi cultivation: there are bottle cultivation method and basswood culture method.

Bottle cultivation method: Before planting, first mix the culture material uniformly according to sawdust (broadleaf tree) 75%, wheat bran 25%, or cottonseed hull 80%, bran 16%, sucrose 1%, gypsum powder 3%. The moisture of the culture material should be such that when squeezed by hand, water appears between the fingers but does not drip. Then put the culture material into culture bottles (or cans), with the filling amount 0.5 cm from the bottle mouth. After filling, use a pointed wooden stick to make a ventilation hole from the middle of the material, then carry out high-pressure sterilization treatment. When the temperature of the sterilized culture material drops to 30°C, inoculation can be carried out. During inoculation, use the steam inoculation method, or inoculate in an inoculation box or inoculation room. First wipe the spawn mouth with a 75% alcohol cotton ball, disinfect tools such as the inoculation groove, and sterilize them beside the flame of an alcohol lamp, then inoculate the spawn onto the culture material. After sterilizing the mouth by flame, wrap the bottle mouth well with kraft paper. Place indoors at 20-26°C for culture. After about 30 days, the mycelium can fill the culture bottle. If culture is continued, fruiting bodies will grow. At this time, the room temperature should be controlled at 26-28°C, the relative air humidity at 90%, and the air should be kept fresh, with a certain amount of scattered light given to favor fruiting body growth.

Basswood cultivation method: In autumn, select broadleaf trees such as peach, poplar, willow, and pagoda tree, with trunks 5-15 cm in diameter, cut them into basswood segments 1 m long, and use an electric drill bit 1-1.2 cm in diameter to make inoculation holes in a triangular arrangement with row spacing and plant spacing of 20×20 cm, with a depth of 1 cm. As holes are drilled, gently insert the spawn into the holes, press slightly tight, cover with bark, and tap level gently with a small wooden hammer. (The inoculation period should be chosen when the air temperature is 20-26°C and the relative air humidity is below 60%.) After about 30 days of inoculation, the mycelium penetrates the basswood, and a brown fungal ring can be seen forming around the holes, indicating successful inoculation. When the mycelium covers the bark cover, it is considered successfully established. At this time, the basswood can be buried in the soil, paying attention to moisture retention, avoiding water accumulation, and preventing and controlling pests and diseases. When the fungus has grown throughout the basswood and fungal primordia appear at the holes, immediately dig out the basswood, cut it into small basswood segments 17-20 cm long, and then bury them obliquely in acidic gravelly soil, with the upper end exposed about 3 cm above the ground. Cover with weeds for shade, and sprinkle water once every few days to keep the soil moist. After 7-10 days, Lingzhi buds begin to grow. At this time, the relative air humidity should be maintained at about 90%; too dry or too wet will both cause the Lingzhi buds to die.

IV. Harvesting and processing: After the spores in the Lingzhi cap have been released, the cap changes from soft to hard, and the color changes from light yellow to reddish-brown. When it no longer grows thicker, it can be harvested. Dry the harvested Lingzhi in the shade in time or dry it at 40-45°C, and then it can be sold as medicine. Every 100 kg of culture material can yield 2-3 kg of dried Lingzhi. Those that are dry, large, reddish-brown, and have a lacquer-like luster are considered superior.