Cultivation techniques of edible fungi Chapter I Basic theories and concepts of edible fungi Section I Structure and name explanation 1. Related terms edible fungi. 1. mycelium: the vegetative body of edible fungi, which is composed of filamentous cells and is the basis for the formation of fruiting bodies (fruiting). The quality of mycelium plays a decisive role in the production, yield and quality of mushrooms. 2. fruiting body: (mushroom) is the fruit produced by mycelium and the inevitable result of its sexual reproduction. Fungal cap: it is the main part of mature fruiting body, and its main function is to protect the fungus fold. Fungal folds: most species are located in the lower part of the fungus cover, arranged in a page or porous shape, which is the place where the burden was born. Basket is a real reproductive organ, with 2-4 basidiospores at the top. When the basidiospores mature, they fall off the burden and are ejected into the air. Stipe: It can transport nutrients and support the whole fruiting body. Volvariella volvacea: Where the stipe is connected with mycelium and growth substrate, sometimes the residue of the outer protective layer of fruiting body is attached, and some varieties have no such structure or are not obvious. Fungal ring: In some species, when the fruiting body is young, the lower part of the fungus cover is covered with a film (inner fungus cover) to protect the young fungus folds from exposure. A species with an endophytic cap is called a fruit quilt entity, and vice versa. During the growth of fruiting body, the inner umbrella cap gradually breaks and falls off, leaving a ring structure on the stalk, called stalk. Of course, there are not all kinds of fungus rings. 3. Life history: that is, life history, in which two basidiospores of different sexes germinate to form two mononuclear hyphae of different sexes, and after mass matching and nuclear matching to form binuclear hyphae, the binuclear hyphae further grow, mature and kink to form fruiting body primordium, and the fruiting body primordium further grows and differentiates to form fruiting bodies, producing burdens inside the fruiting bodies, forming basidiospores on the basidiospores, and after the basidiospores mature, they are ejected into the air and will germinate into mononuclear hyphae again under suitable conditions. Section II Nutritional Requirements of Edible Fungi Most edible fungi are saprophytes. They can't directly use inorganic substances and the energy of sunlight to grow like green plants, but only rely on decomposing and oxidizing organic substances to absorb the nutrients and energy needed for their own growth. The growth of edible fungi can be roughly divided into vegetative growth stage (spawning) and reproductive growth stage (fruiting). Inoculating the mycelium on a suitable culture medium, at a suitable temperature, it began to secrete a series of enzymes, which decomposed some macromolecular organic substances into simple water-soluble small molecular substances and absorbed them into cells for their growth and development. Different growth stages have different requirements for nutritional conditions. Generally speaking, the nitrogen content in the culture medium of mycelium growth stage is relatively high, and the nitrogen content in the culture medium of fruiting body development stage is relatively low. Therefore, as far as scientific research and production are concerned, the nutrients added to the culture medium at different stages should be different. For example, during the preservation and production of strains, more nitrogen sources should be added to the culture medium, which is beneficial to the growth and development of mycelium on the one hand and can effectively prevent the premature growth of mushrooms on the other; However, nitrogen sources should be relatively reduced in the formula of cultivation materials for mushroom production, which is beneficial to mushroom production. 1. Carbon source: Different from green plants, fungi can't directly use CO2 as carbon source to synthesize organic matter, but can only use organic matter as carbon source, such as monosaccharides and disaccharides such as glucose, sucrose and maltose, and polysaccharides such as starch, cellulose, hemicellulose and lignin. Except glucose can be directly absorbed and utilized by hyphal cells, other enzymes secreted by hyphae must be hydrolyzed into monosaccharides before they can be absorbed and utilized. Nitrogen source: Organic nitrogen is the best nitrogen source for edible fungi, such as peptone, yeast extract, bran and rice bran. Natural cultivation substrates such as cottonseed hull, sawdust and plant straw also contain some nitrogen sources that can be absorbed and utilized by edible fungi, but the content is not enough, so it is necessary to add materials with high nitrogen content such as bran and rice bran, and some special varieties also need to add industrial preparations such as peptone and yeast extract. Inorganic nitrogen and small molecular organic nitrogen, such as various nitrogenous fertilizers, are easy to produce ammonia under the action of microorganisms to inhibit the growth of hyphae, so they should not be added to the culture medium unless there is special need, and can be used as topdressing if necessary. Carbon-nitrogen ratio: refers to the ratio of carbon source to nitrogen source in culture medium and culture solution. Taking Pleurotus ostreatus as an example, the ratio of carbon to nitrogen in mycelium growth stage is 20/ 1, and that in fruiting body development stage is 40/ 1. 3. Other nutrients: In addition to carbon and nitrogen sources, the growth and development of edible fungi also need some other nutrients, such as mineral elements such as calcium, phosphorus, magnesium, zinc, iron, copper, sulfur, potassium and manganese, as well as various vitamins and growth factors. Section III Requirements of Edible Fungi on Environmental Conditions. Environmental factors: Environmental factors are very important to all stages of the growth and development of edible fungi. First, understand the relevant environmental factors, clarify the concepts, and then comprehensively control them: 1. Water is not only the necessary environmental condition for mycelium growth, but also the main component of biological cells. Proper water content in the substrate is very important for the growth of mycelium and the development of fruiting body. If the water content of the substrate is too low, the mycelium is not conducive to the decomposition of the substrate and the absorption of nutrients, which will weaken the mycelium and seriously affect the yield of mushrooms. If the water content of the substrate is too high, the mycelium below will lack oxygen and stop eating, resulting in the waste of raw materials. At the same time, the surface hyphae grow in vain, and the material area is water, which makes the hyphae autolyse and leads to mixed bacteria pollution. Most species require that the water content of substrate is about 65%, that of Lentinus edodes is between 565,438+0 ~ 55%, and that of Pleurotus ostreatus can sometimes be controlled between 65 ~ 70%. The calculation formula of water content of matrix (weight ratio): 2. PH value: pH value refers to the pH value of water (and water-containing substances), and the specified range is 0 ~ 14, where pH =7 is neutral, pH > 7 is alkaline, and pH < 7 is acidic. ├ ├ ┤ ┼ ┤ 0 ┼ ┼ ┼ ┼ ┼ ┼ ┼ ┼ ┼ ┼ ┼. The dividing value is 0.5 pH unit, the range of 5.5 ~ 9 is 5.5 ~ 9, the dividing value is 0.5 pH unit, the range of 8.0 ~ 14 is 8.0 ~ 14, and the dividing value is 0.5 pH unit. Different varieties adapt to different pH ranges, which are determined by their own acid-producing ability in physiological metabolism and their biological enzyme activity range. 3. Aerated edible fungi belong to aerobic microorganisms, which rely on the organic matter in the oxidation matrix to provide the energy needed for their growth and development. Substrate hypoxia can inhibit the respiration of mycelium, leading to slow growth, weakness, or even stop growth, and even death due to suffocation; Hypoxia in fruiting body stage will cause deformity of fruiting body and affect commodity value. 4. Temperature: Temperature is a physical quantity indicating the degree of hot and cold of an object. The standard for measuring temperature is called temperature scale, and the commonly used temperature scale in the world is centigrade scale: at standard atmospheric pressure, the temperature when water begins to freeze is set to 0, and the temperature when water boils is set to 100, which is divided into 100 equal parts, and each equal part is defined as 1 Celsius (℃). Each variety has its own temperature adaptation range, even the same variety has its mycelium stage. According to the different suitable temperature ranges for fruiting body differentiation, edible fungi can be divided into low-temperature, medium-temperature and high-temperature types: ① The low-temperature type can only differentiate fruiting bodies at a lower temperature, and the optimum temperature is below 20℃, and the highest temperature is not more than 24℃, such as: Lentinus edodes, Flammulina velutipes, Agaricus bisporus, Pleurotus ostreatus, Morchella, Hericium erinaceus and so on. ② The optimum temperature for the differentiation of mesophilic fruiting bodies is 20 ~ 24℃, and the highest temperature should not exceed. (3) The high-temperature fruiting body differentiation needs to be carried out at a higher temperature, and the optimum temperature is above 24 ~ 28℃, and the highest temperature can reach about 40℃. Such as straw mushrooms, anchovies, abalone mushrooms, etc. At the same time, there are varieties with low and medium temperature, high and medium temperature and wide temperature. In addition, different varieties have different responses to temperature changes during the formation of fruiting bodies. According to this, edible fungi can be divided into the following two types: constant temperature mushroom type can form fruiting bodies at a certain constant temperature, such as Flammulina velutipes, Agaricus bisporus, Auricularia auricula, Volvariella volvacea, Hericium erinaceus and so on. The mushroom-growing type with variable temperature keeps constant temperature, does not form fruiting bodies, and only forms when the temperature changes (temperature difference stimulation is needed). Such as: mushrooms, Pleurotus ostreatus, Pleurotus eryngii, Pleurotus ferulae (Pleurotus nebrodensis) and so on. 5. Air humidity As mentioned above, the water content of the substrate is very important for the growth of hyphae, but it is completely or partially exposed to the external environment during the growth and development stage of fruiting bodies, so the water content of the air, that is, air humidity, has become one of the main influencing factors. Too low air humidity will accelerate the evaporation of water on the surface of fruiting body, and the evaporated water of fruiting body mainly comes from mycelium in the substrate, which will lead to a large loss of water in the substrate, affect the yield, and even make the primordium of fruiting body dry up and die. The evaporation of water is the driving force for hyphae to transport nutrients to fruiting bodies. If the air humidity is too high, it will prevent the evaporation of water on the surface of the fruiting body, hinder the transportation of nutrients, inhibit the respiration and stop the growth of the fruiting body. If the air humidity is too high for a long time, it will also cause the fruiting body to absorb water from the air, which will be very dangerous, especially the aging fruiting body, which will form water rot, leading to the breeding of nematodes and bacteria and large-scale infection. Therefore, it is very important to maintain proper air humidity. Most varieties require air relative humidity between 80% and 95% at the fruiting stage. Experienced mushroom house managers can judge whether the air humidity is appropriate by feeling, but it is often very difficult for novices. There is a need for a scientific measurement method-hygrometer to measure accurately. (1) the concept of air humidity and its measurement: ① concept: air humidity refers to the water content of air, which can be expressed in two ways: absolute humidity and relative humidity. Absolute humidity: refers to the partial pressure of water vapor in the air, that is, the water actually contained in the air. Relative humidity: refers to the percentage of absolute humidity at a certain temperature and water vapor saturation at the same temperature. Water vapor saturation: refers to the saturated vapor pressure at a certain temperature. There is enough water in the closed container, and the water begins to evaporate. Under the condition of constant temperature, the evaporation and condensation of water reach an equilibrium state after a period of time, and the partial pressure of water vapor at this time is the water vapor saturation at this temperature. If the temperature rises, water will continue to evaporate until it reaches a new equilibrium point, at which time the partial pressure of water vapor is higher than the former; If the temperature drops, dew will condense on the inner wall of the container, and the partial pressure of water vapor will drop accordingly until it reaches another equilibrium point, namely saturation. Therefore, the water vapor saturation varies with temperature. There is a positive correlation between temperature increase, saturated vapor pressure increase, temperature decrease and saturated vapor pressure decrease. From the above calculation formula of air relative humidity, it is concluded that if the absolute humidity of air is constant, the relative humidity of air is negatively correlated with the change of temperature, that is, the relative humidity of air decreases with the increase of temperature; On the contrary, the temperature drops and the relative humidity of the air rises. ② Measurement of air humidity: It is troublesome to directly measure the absolute humidity of air, which has no practical significance in our production. Here I mainly talk about the measurement of air relative humidity. At present, there are two kinds of instruments widely used: dry and wet bulb thermometer and hair hygrometer. Dry and wet bulb thermometer: (see figure) consists of two thermometers with the same structure, one of which is directly exposed to the air as a dry bulb; The other bulb is tied with a gauze tape, and the other end of the gauze tape is soaked in a water dish as a wet ball. Working principle and usage: dry bulb thermometer directly measures air temperature, that is, drying temperature. On the wet bulb thermometer, due to the capillary action of gauze strips, water evaporates on the surface of the bulb, taking away some heat, so that the temperature indicated by the wet bulb thermometer (wet temperature) is lower than that indicated by the dry bulb, thus forming a wet-dry difference. The relative humidity of the air can be found by looking up the table. ③ Selection, use and maintenance of dry and wet bulb thermometers: Selection of dry and wet bulb thermometers: If you want to choose products from regular manufacturers, it is best to bring them. Sign. Selection criteria: plastic chassis, clear and firm printing, initial wet-dry difference of "0", firm connection between columns and graduated chassis, reasonable placement of water tray, easy to fall off and not easy to fall off. Use of dry and wet bulb thermometer: In order to prolong the service life of the instrument, it is best to add distilled water or boiled water to the water tray instead of raw water directly. You also need to pay attention to the position of the watch and choose a representative place. In general, a greenhouse with 100 meters needs to be hung with 2 ~ 3 dry and wet bulb thermometers. When looking up the meter, don't hold the place near the light bulb by hand, so as not to affect the reading of the meter. Write down the readings of dry bulb and wet bulb respectively, calculate the difference between wet and dry, and find out the relative humidity of the air at that time from the look-up table. Maintenance of dry and wet bulb thermometer: When there is too much water and alkali on the gauze strip on the wet bulb, it can be cleaned with dilute hydrochloric acid or acetic acid. If it cannot be cleaned or damaged, it should be replaced with hollow shoelaces. When the measurement result is in doubt, it should be calibrated: soak the dry bulb and wet bulb of the dry-wet bulb thermometer in constant temperature water at the same time, put a standard thermometer next to it, observe their readings after 5 minutes, and record the error value, so as to eliminate the error in future use; If the error is large, it is necessary to check whether the dislocation between the column and the dial is loose, and then re-fix it with resin glue or glass glue after reset. During the whole calibration process, the bulb must always be submerged in water. (2) Control of air relative humidity: If you understand the concept of air relative humidity, you can carry out targeted control. The change of air relative humidity is also affected by temperature and ventilation, which will be explained in detail later. 5. Aerated edible fungi belong to aerobic bacteria, and both mycelium growth and fruiting body development need sufficient oxygen. The breathing function of edible fungi, like human breathing, consumes oxygen in the air and releases CO2. Appropriate CO2 concentration can stimulate and promote the growth of some kinds of hyphae, but excessive CO2 accumulation will inhibit the growth of hyphae, or even stop the growth completely, and high CO2 concentration will lead to hyphae suffocation and death for a long time. The fruiting body stage is more sensitive to CO2, which is mainly manifested in inhibiting the differentiation of the cap, making the stipe too long and reducing the grade of the finished product. Therefore, it is necessary to ventilate the space of mushroom house frequently, remove CO2 and keep the air fresh. 6. There is no need for illumination in the mycelium stage of edible fungi.