Figure 2-4 Nutrition, Propagation Stage and Transformation Excitation Point of Grifola frondosa
1. temperature The growth and development of Grifola frondosa must be carried out under certain temperature conditions, and the temperature range suitable for the growth and development of Grifola frondosa is called the effective temperature zone. The effective temperature range of Grifola frondosa is 5 ~ 32℃. Above or below this temperature range, the enzyme will be passivated, its activity will be reduced, and its growth and development will be affected. The lower limit of the effective temperature zone is the initial temperature of growth and development (5℃), and the upper limit of the effective temperature zone is the highest effective temperature (32℃). Within the effective temperature range, the three stages of Grifola frondosa's vegetative growth, primordium generation and fruiting development all have their own requirements for the optimal temperature, and the growth and development are in the best state in the optimal temperature range of each stage.
The environmental temperature requirements of Grifola frondosa vegetative growth, primordium generation and mushroom development are as follows:
The growth temperature of (1) mycelium is 5 ~ 32℃, which is the effective growth temperature zone of Grifola frondosa mycelium, and the suitable temperature zone is 20 ~ 25℃. It should be pointed out that the optimum temperature for mycelium growth refers to the fastest temperature for mycelium growth. However, this temperature is often not suitable for the healthy growth of mycelium. Because at higher temperature, the physiological metabolism is too fast, and the mycelium growth is sparse and weak. In addition, the growth and development of a large number of hyphae will produce respiratory heat, which will make the temperature in the culture material higher than room temperature 1 ~ 3℃, and the temperature in the spawning room should be controlled at 20 ~ 22℃ in production practice.
The mycelium of Grifola frondosa has strong resistance to low temperature. Under the condition of antifreeze protection, Grifola frondosa mycelium can be stored at the ultra-low temperature of-196℃ for several years without losing vitality. The mycelium of Grifola frondosa is much more sensitive to high temperature than low temperature, and its mycelium can be inactivated at 40℃ for 6 hours, 42℃ for 3 hours and 45℃ 1 hour.
(2) The temperature of primordial differentiation of Grifola frondosa is mesophilic mushroom, and the temperature range of primordial differentiation is 18 ~ 22℃, which is slightly different due to different high-temperature and low-temperature varieties.
(3) The temperature range of mushroom growth is 10 ~ 25℃, and the optimum temperature range is 18 ~ 23℃. If the temperature is low and the growth is slow, the quality of mushroom body is better; If the temperature is high, it grows fast, but it is easy to age.
Grifola frondosa mycelium began to grow above the growth threshold temperature (6℃), so the temperature below the growth threshold temperature should be subtracted when calculating its effective accumulated temperature. For example, the effective accumulated temperature of Grifola frondosa strains planted in sawdust bags at 22℃ is calculated as follows: the daily average temperature is 22℃, which is reduced by 5℃ before the growth start point, and the effective accumulated temperature is 17℃×50 days =850℃, that is, the accumulated temperature of growth and development can reach this amount before fruiting, otherwise it can only be fruiting at 22℃ for about 50 days. If the spawning temperature is lower than 22℃, the required days will increase. In addition, at the same temperature, the comparison of Grifola frondosa and Lentinus edodes showed that the growth rate of Grifola frondosa was slightly slower than that of Lentinus edodes. Therefore, in the production of Grifola frondosa, it should be sufficient to arrange the growth period of fungi.
2. Moisture and humidity Water is the main component of Grifola frondosa, and the water content of its mycelium and fruiting body is about 90%. Water is also an essential basic medium for biological metabolism, transport and transformation of nutrients. Therefore, the culture material of Grifola frondosa needs a certain water content, and the air also needs a certain relative humidity.
When inoculated, the water content of the culture medium is generally 55% ~ 63%. When the water content is too low, the bacteria will not develop; when the water content is too high, the air permeability of the culture medium is poor, and the bacteria are difficult to develop. For example, it is known that the water content of sawdust and wheat bran is 13%. The formula is sawdust 80% and wheat bran 20%.
The relative humidity of the air during the growth period of auricularia auricula can be kept at about 60%, and it is easy to be infected with miscellaneous bacteria if it is too high. At the stage of primordium differentiation and fruiting body development, the suitable air relative humidity is 85% ~ 90%. If it is less than 50%, the primordium will not differentiate, and even the differentiated young mushrooms will wither and die. The relative humidity of the air during the growth period of auricularia auricula can be kept at about 60%, and it is easy to be infected with miscellaneous bacteria if it is too high. At the stage of primordium differentiation and fruiting body development, the suitable air relative humidity is 85% ~ 90%. If it is less than 50%, the primordium will not differentiate, and even the differentiated young mushrooms will wither and die.
3. The standard components of oxygen outdoor fresh air are: nitrogen (N)78%, oxygen (O2)2 1%, carbon dioxide (CO2)0.03%, and the rest are inert gases such as argon (A) and neon (Ne).
Grifola frondosa is an excellent aerobic mushroom, which needs more oxygen than other edible fungi. The mushroom room must be ventilated 5 ~ 6 times a day. The oxygen demand in the mycelium growth stage is less than that in the fruiting stage, but it can't be deprived of oxygen, otherwise the mycelium cells will temporarily maintain their life activities by glycolysis and consume a lot of nutrients, and the mycelium will gradually weaken and shorten its life. When there is severe hypoxia, the growth of mycelium is blocked. Therefore, the mushroom shed should be ventilated frequently to keep the air fresh. In the development stage of mushrooms, oxygen demand increases. If the concentration of carbon dioxide in the air is high, it will affect the development of mushrooms and cause coral deformity. In severe cases, mushrooms will stop growing.
In order to verify the influence of temperature, humidity and ventilation conditions on the growth of Grifola frondosa, Chen et al. (1995) put the budded fungus bags in three different humidity and ventilation environments to grow mushrooms, and recorded the temperature of the mushroom room at 6 am and 13 pm every day. The results show (Table 2-4) that Grifola frondosa is suitable for growth from April to June. In late June, the average temperature of 6 o'clock and 13 in the mushroom house was 24℃ and 29℃, respectively, and the mushroom body could still grow normally. By the beginning of July, the average temperatures at 6 o'clock and 13 were 29℃ and 3 1℃, respectively, and the mushroom stopped developing. Therefore, the high temperature of about 30℃ should be avoided during the cultivation of Grifola frondosa. The conditions of high humidity and poor ventilation are not conducive to the development of mushrooms.
Table 2-4 Effects of temperature, humidity and ventilation on fruiting of Grifola frondosa.
4. mycelium growth does not need strong light, so the culture shed needs shading, and the illumination is 15 ~ 50 lux. Too much light will affect the growth of hyphae. It can't be completely black, otherwise the mycelium will grow too thick and form a "cap". Stimulating primordium formation and fruiting body development requires strong scattered light. Generally, 200 ~ 500 lux (fluorescent lamp or light intensity before sunset) can promote primordium to turn gray-black, so as to develop into normal mushroom body. Moreover, the stronger the scattered light, the darker the color of the mushroom cover, the stronger the fragrance and the better the quality; On the contrary, the color is light and the quality is poor. The serious lack of light also affects the differentiation of fruiting bodies, leading to deformity. Using yellow light to inhibit the formation of Grifola frondosa primordium can delay the formation of primordium from 40 ~ 45 days to 60 ~ 65 days, which can be delayed by about 20 days. Due to the increase of nutrient accumulation, mushrooms are neat and robust, and the yield can be increased by about 15%.
5. Grifola frondosa with pH value is suitable for weak acid environment, and the mycelium can grow in the range of pH value 4 ~ 7.5, and the optimum pH value is 5.5 ~ 6.5. Excessive acid or alkali is not conducive to the growth and development of Grifola frondosa. The pH value of the culture medium gradually decreased with the growth time of Grifola frondosa. When the initial pH value is pH6.5, it can be reduced to pH4 after 10, and it will be maintained until fruiting. Song Airong et al. (1999) measured the growth of Grifola frondosa fermentation broth and mycelium under different pH conditions and the same pH conditions. The results showed that the initial pH value of Grifola frondosa fermentation broth was pH8, and the pH value after mycelium growth was about 5.