In order to ensure the growth environment of the edible fungus hyphae in the greenhouse, the latest lighting technology-light dimming LED cold light source is used as the artificial main light source for the light environment. At the same time, the effects of different light conditions of LED light on the growth characteristics of Pleurotus ostreatus mycelium were studied, so as to find the growth environment of Pleurotus ostreatus with short cycle and high quality, which provided a basis for the industrial cultivation of edible fungi in the north. .
In recent years, with the improvement of people's living standards, people pay more attention to food safety and food nutrition problems, and gradually began to change the vegetables and meat that provide daily energy to edible fungi. Studies have shown that most edible fungi contain essential amino acids, vitamins and minerals that can supplement daily nutritional needs. As an important food resource for human beings, edible fungi have important drug value and certain ornamental value in addition to the characteristics of good taste and nutrient-rich.
China is the country with the largest output of edible fungi. After joining the WTO, the edible fungus industry occupies a clear dominant position in the international market. According to statistics, China's edible fungi account for about 50% of the world's, medicinal products account for 70% of the world, but only 60 species can be cultivated. Therefore, in order to achieve the industrial production of edible fungi, it is necessary to find the most suitable growth environment factor for the edible fungi, thereby achieving efficient development of the cultivation technology of the edible fungi facility. Most edible fungi growers pay more attention to temperature and humidity, but light is also a non-negligible factor in the growth of edible fungi.
In this paper, the latest energy-saving and environmentally-friendly semiconductor technology LED is used as the main control artificial light source instead of the traditional light source. It has the absolute advantages of pure light quality, high luminous efficiency and low heat dissipation. For the LED power supply part, the dimmable drive control mode is adopted, which is characterized by eliminating the fluctuation of the power grid, ensuring the stability and reliability of the power supply system, and realizing the brightness adjustable function, which can meet the requirements of the test for the light environment.
In this paper, Pleurotus ostreatus was used as the object to study the effects of different LED light quantity and light quality conditions on the growth of Pleurotus ostreatus stage, so as to screen out the most suitable light conditions of Pleurotus ostreatus, aiming at the industrialization and variety of edible fungi. The growth cycle environmental factors provide a strong basis, and further promote the development of industrialization of edible fungi with high yield, short cycle and variety.
Hardware structure and working principle
To ensure that the LED lamp can operate normally and has dimming function, the key point is that the power supply part can supply power stably and reliably. The power circuit includes an EMI filter circuit, a full bridge rectifier circuit, a chopper circuit, a clamp circuit, a transformer, a rectification filter circuit, and a dimming control circuit, as shown in FIG.
Figure 1 power circuit block diagram
LED lamp dimmable power supply driver circuit diagram shown in Figure 2. Working principle: After the AC power is connected, the EMI primary filter will instantaneously filter out the high voltage, turn it into DC through the full bridge rectifier, and then pass the secondary filter circuit to protect the LED lamp from being instantaneously broken by high voltage. The flyback converter is realized by an RCD clamp circuit, a transformer, and a switch tube. The chopper circuit and the dimming drive controller iw3612 realize any adjustment function of brightness between 1% and 100% without affecting the life of the LED lamp. The DC that is rectified and filtered by the secondary end of the transformer is directly connected to the LED lamp to meet the test requirements for light.
test
Test material Pleurotus ostreatus: provided by the College of Resources and Environment of Northeast Agricultural University.
PDA medium: 200g of potato (peeled, boiled, juiced), agar 20g, glucose 20g, added water to 1000mL, for the growth of Pleurotus ostreatus mycelium.
Test equipment
1) Edible fungus biochemical incubator: 6 SFX-250B-Z biochemical incubators are provided by Shanghai Boxun Industrial Co., Ltd. Medical Equipment Factory to realize the setting and display of temperature, humidity, CO2 concentration and ventilation.
2) Light source: LED light with dimming function, one each of red, orange, yellow, green, blue and white, size 400mm×400mm.
3) Illuminometer: TES brand TES1339 high-precision professional illuminance meter, measuring range 0.01 ~ 999 900lux level, using calibration metric 1lux. .
experiment method
The experiment was carried out in the Laboratory of Microbial Species of Northeast Agricultural University. The three culture dishes of the Pleurotus ostreatus strains were placed in a biochemical incubator equipped with LED white light, dark conditions and natural light (control group), the temperature was set at 24 to 25 ° C, and the humidity was set at 60. % ~ 70%, to ensure CO2 concentration and timing ventilation. The LED lamp was 30 to 875 px from the Pleurotus ostreatus strain. After one day of inoculation, the average diameter of the colony was measured periodically to observe the change of the hyphae of Pleurotus ostreatus under different light conditions.
Six groups of Pleurotus ostreatus culture dishes were placed in an edible fungus biochemical incubator equipped with red, orange, yellow, green, blue and white dimmable LED lamps. Temperature, humidity, CO2 concentration, ventilation settings Same as above, another set of natural light (control group). The LED lamp was tested from the Pleurotus ostreatus strain 30 to 875px. After one day of inoculation, the diameter of the colony was measured regularly every day, and the average growth rate and morphological characteristics of Pleurotus ostreatus [9-10] under different light conditions were observed.
Data Processing: The measurement data was processed and analyzed using MatLab software.
Test results and analysis
Effects of Different Light Amounts on the Growth of Pleurotus ostreatus Mycelium
Test data: The hyphal growth data of the mycelium of Pleurotus ostreatus strains under natural, dark and LED white light conditions are shown in Table 1.
Table 1 Growth data of Pleurotus ostreatus under different LED light conditions: cm
It can be seen from Table 1 that the average growth of the mycelial diameter in the dark and LED white light conditions is not obvious, but the average daily diameter growth length of the two is significantly higher than that of the control group (natural). According to the test data in Table 1, the scatter plots of the mycelium of Pleurotus ostreatus under natural, dark, and white LED light are plotted. In these three cases, nonlinear changes are presented. Linearization and comparison of the growth curves fitted by MatLab showed that it is more suitable to select the 3 curve model. The regression equation is y = ax3 + bx2 + cx + d ( x >0)
Curve fitting and regression analysis
Using MatLab to perform curve fitting on the test data in Table 1, the growth curve model and the best fit curve of Pleurotus ostreatus mycelium under different light conditions can be obtained [12], as shown in Figure 3.
Fig. 3 Fitting curve of Pleurotus ostreatus under different LED light conditions
According to the fitting curve in Fig. 3, the growth curve of Pleurotus ostreatus hyphae under natural, dark and LED white light conditions can be respectively obtained as y1 = - 0.01x3 + 0.2x2-0.46x + 0.94, y2 = - 0.01x3 + 0.2x2-0.22x + 0.76, y3 = - 0.18x3 + 0.3x2- 0.6x + 1.13, where y1, y2, y3 represent the hyphae diameter of natural, dark, LED white light, respectively; cm; x is the number of days, d . The analysis results after MATLAB fitting show that: y1, y2, y3 determine the coefficient R2 are 0.997, 0.999, 0.998, which are close to 1; the calibration standard deviation RMSEC are 0.122, 0.068, 0.117, respectively. Within the controllable range, the significance level is 0 < 0.05, indicating that the degree of fit is good and significant.
The effect of different light quality on the growth of Pleurotus ostreatus hyphae under different light conditions of LED light source, the average daily growth rate of Pleurotus ostreatus diameter within 10 days is shown in Fig. 4. In Figure 4, the LED light treatment group is superior to the natural group. The order of growth rate of hyphae is: red, orange, green, yellow blue, white, and the average daily growth rate of yellow and blue is close, the change is not obvious. For the 6 kinds of light treatment of the test group, the average daily growth rate of Pleurotus ostreatus by LED red light treatment was 5.12550px /d, and it reached 5.183, 5.1175px/d for orange and green, and processed for yellow, blue and white light. Lower, 4.428, 4.395, 4.3400px/d. Therefore, the LED light source treatment fully demonstrates the sensitivity of Pleurotus ostreatus to light quality.
Figure 4 Growth rate of Pleurotus ostreatus under different light conditions
The effects of different LED light quality on the culture characteristics of Pleurotus ostreatus mycelia are shown in Table 2.
It can be seen from Table 2 that the hyphae density of the red light source is very dense, followed by the orange and green hyphae density, and the natural hyphae are sparse. From the morphology of the colonies, the red, orange, and green colonies grow in a thread shape, and the natural and white-lighted colonies exhibit hyphal radioactive line shape growth. From the color point of view, there is no obvious change in each group. From the perspective of the uniformity of the edges, the orange is more neat and the yellow is not neat.
According to the analysis of Figure 4 and Table 2, under different light conditions of LED light source, red light is more suitable for the growth of Pleurotus ostreatus, followed by orange light and green light. The method is the same as above, and the regression equation under the optimal growth curve of Pleurotus ostreatus under red light conditions can be obtained as y4 = 0.000 3x5_ 0.004 9x4 -0. 016 4x3 +0.470 2x2 - 0.722 3x + 1.72 where y4 - represents Hyphae diameter (cm) of LED red light; x - days (d). The determination coefficient R2 is 0.999, which is close to 1; the calibration standard deviation RMSEC is 0.12, and the test error is within the controllable range; the significant level is 0<0.05, indicating that the degree of fit is good and significant.
in conclusion
The test showed that the mycelium of Pleurotus ostreatus changed significantly under dark and LED white light conditions compared with the control group, but the change between the two was not obvious. LED red light is most suitable for the growth of Pleurotus ostreatus mycelium, orange, green followed by yellow, blue, white light under three conditions, the hyphae of Pleurotus ostreatus is not obvious. At the same time, the curve fitting was performed by MatLab to establish the optimal growth model for Pleurotus ostreatus, and the growth characteristics of Pleurotus ostreatus hyphae were fully understood, which provided a favorable basis for the research of greenhouse mushroom monitoring system in the future.
