Substrate for propagation of a strain of the fungus conidiobolus lampraugus and method for its preparation

Abstract

The present application relates to the field of biotechnology, in particular to a propagation substrate of a Claroideoglomus lamellosum strain and a preparation method thereof. The Claroideoglomus lamellosum strain CXL-18 of the present application is a strain screened by the applicant, which has been disclosed in patent CN116004402A. At present, there is no suitable propagation system for the propagation of the strain on the market. According to the growth characteristics of the strain, a substrate for the strain CXL-18 is obtained, which has good and stable propagation effect, high abundance of cluster roots and significantly promotes spore propagation. The propagation effect of the substrate is better than that of all commercially available substrates. The substrate can provide a wider application prospect for the rapid propagation of the dominant strain CXL-18.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of biotechnology, in particular to a propagation substrate of a Claroideoglomus lamellosum strain and a preparation method thereof. BACKGROUND

[0002] Arbuscular mycorrhizal (AM) fungi can infect most terrestrial plants, have the characteristics of promoting plant nutrient absorption, improving plant stress resistance, and improving soil ecology, and have a positive effect on agricultural production and ecological protection. However, as a specific living symbiotic fungus, AM fungi cannot decompose organic matter in the soil as a source of carbohydrates needed for growth, and their nutrition mainly comes from photosynthetic products of host plants (such as corn, sorghum, alfalfa, etc.), so the propagation of AM fungi is mainly through symbiosis with host plants (such as corn, sorghum, alfalfa, etc.) to obtain AM fungal spores.

[0003] AM fungal propagation is usually affected by many factors such as culture medium, host plant, fungal strain, nutrient supply and culture time, and the propagation effect varies greatly. The mainstream AM fungal propagation substrate at present is composed of river sand and soil of different particle sizes mixed in a certain proportion (1:1 or 2:1), and the nutrient supply is based on chemical fertilizer or irrigation of 50% low-phosphorus Hoagland nutrient solution. This propagation method has the following problems: first, the applicability of different strains is different. The conventional propagation substrate is suitable for common AM fungal species on the market, most of which belong to Rhizophagus, Glomus and Funneliformis, and in fact the optimal pH and nitrogen and phosphorus conditions for the growth of different AM fungi are also different. The conventional substrate may not meet the best propagation conditions for non-commercial AM fungal species (such as Claroideoglomus); second, the acquisition of soil in the substrate is complicated and unstable. Since high phosphorus content can inhibit the growth of AM fungi, the source of soil in the substrate requires low-phosphorus soil, which on the one hand raises the threshold for obtaining substrate materials, and on the other hand the difference in soil texture in different regions also causes the physical and chemical properties of the substrate to be unstable, resulting in good and bad propagation effects; third, the nutrient supply is unreasonable. The conventional chemical fertilizer base application may result in excessive basic available nutrients in the substrate, thereby inhibiting the growth of AM fungi, and only irrigation of 50% Hoagland nutrient solution may result in insufficient nutrient supply, and the actual operation is also more complicated.

[0004] The Claroideoglomus lamellosum strain CXL-18 is a strain screened by the applicant and has been disclosed in patent CN116004402A, and there is no suitable propagation system for this strain on the market. Since the current AM fungal propagation technology still has many limited conditions, it is difficult to meet the needs of actual production, therefore, it is necessary to explore a more efficient and stable propagation system for different AM fungal strains. SUMMARY

[0005] In view of the above, the Claroideoglomus lamellosum strain CXL-18 is a strain screened by the applicant, and there is no suitable propagation system for the strain on the market at present, so it is necessary to explore a more efficient and stable propagation system for the Claroideoglomus lamellosum strain.

[0006] The propagation substrate of the Claroideoglomus lamellosum strain is mixed by SPB substrate and plant source organic fertilizer according to a volume ratio of 17:3; the SPB substrate is mixed by river sand, perlite and bentonite according to a volume ratio of 6:3:1.

[0007] Further, the Claroideoglomus lamellosum strain is CXL-18, the preservation number of which is CGMCC NO.40331, the strain is preserved in the China General Microbiological Culture Collection Center, the address of which is No.1, Beichen West Road, Chaoyang District, Beijing, and the preservation date is October 17, 2022.

[0008] The application also includes a method for preparing the propagation substrate, and the method is:

[0009] (1) preparing plant source organic fertilizer in advance;

[0010] (2) mixing river sand, perlite and bentonite according to a volume ratio of 6:3:1 to obtain SPB substrate;

[0011] (3) mixing the plant source organic fertilizer in step (1) and the SPB substrate in step (2) according to a volume ratio of 17:3 to obtain the propagation substrate.

[0012] Further, the plant source organic fertilizer is purchased from Nanjing Mingzhu Fertilizer Co., Ltd.

[0013] Further, the pH of the propagation substrate is 8.61±0.04, the conductivity is 932.41±19.06 mu s / cm, the organic matter is 32.31±2.98 g / kg, the available nitrogen is 78.75±21.86 mg / kg, the available phosphorus is 18.74±1.73 mg / kg, the available potassium is 562.81±38.71 mg / kg, the available calcium is 1422.69±48.85 mg / kg, the available magnesium is 198.73±5.20 mg / kg, the available iron is 19.86±2.29 mg / kg, the available manganese is 8.81±0.37 mg / kg, the available copper is 0.89±0.15 mg / kg, and the available zinc is 5.90±0.76 mg / kg.

[0014] Further, the plant source organic fertilizer is a reed stalk plant source organic fertilizer and / or a sweet leaf chrysanthemum straw plant source organic fertilizer.

[0015] Further, the mass ratio of the reed stalk plant source organic fertilizer and the sweet leaf chrysanthemum straw plant source organic fertilizer is 1-2:2-3.

[0016] Further, the preparation method of the reed stalk plant source organic fertilizer and / or the sweet leaf chrysanthemum straw plant source organic fertilizer is:

[0017] (1) first, a mixed base straw is prepared: rice straw and corn straw are crushed and mixed according to a mass ratio of 1:1 to obtain the mixed base straw;

[0018] (2) reed stalk-sweet leaf chrysanthemum straw is prepared: the reed stalk and the sweet leaf chrysanthemum straw are crushed and mixed according to a corresponding mass ratio to obtain the reed stalk-sweet leaf chrysanthemum straw;

[0019] (3) the mixed base straw of step (1) and the reed stalk-sweet leaf chrysanthemum straw are uniformly mixed and then are subjected to composting at room temperature for 30 days, and then are dried to obtain the corresponding plant source organic fertilizer.

[0020] The present application has the following beneficial effects:

[0021] The Claroideoglomus lamellosum strain CXL-18 of the present application is a strain screened by the applicant and has been disclosed in patent CN116004402A. At present, there is no suitable propagation system for the propagation of the strain on the market. According to the growth characteristics of the strain, the present application obtains a substrate for the propagation of the strain CXL-18, which has good and stable propagation effect, high abundance of clump branches and significantly promotes spore propagation. The propagation effect of the substrate is better than that of all commercially available substrates. The substrate can provide a wider application prospect for the rapid propagation of the dominant strain CXL-18. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Figure 2 is a graph showing the effects of different substrates on the growth of corn.

[0023] Figure 2 This is a graph showing the effect of different substrates on spore density.

Detailed Implementation Methods

[0024] The present invention will be further described below with reference to the accompanying drawings, embodiments, and experiments.

[0025] Example 1:

[0026] 1. Test strain: Claroideoglomus lamellosum strain CXL-18 was used in the experiment. This strain is deposited at the China General Microbiological Culture Collection Center (CGMCC), address: No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, accession number CGMCC NO.40331, deposit date: October 17, 2022. It was obtained by propagating the original strain in a conventional propagation substrate using corn as the host. The spore density of the inoculum was approximately 54.6 spores / g soil.

[0027] 2. Test plant: Maize (Zeamays L.) variety Suyu 29.

[0028] 3. Cultivation substrate: River sand, perlite, bentonite, and plant-derived organic fertilizer (purchased from Nanjing Mingzhu Fertilizer Co., Ltd., which is obtained by fermentation of straw and Chinese medicine residue) were mixed in different volume ratios as shown in Table 1, which included 7 treatments: (1) SB, river sand: bentonite = 1:1 (v / v); (2) SP, river sand: perlite = 2:1 (v / v); (3) SQB, river sand: quartz: bentonite = 6:3:1 (v / v); (4) SPB, river sand: perlite: Bentonite = 6:3:1 (v / v); (5) SPBO5, SPB substrate and plant-derived organic fertilizer were mixed at a ratio of 19:1 (v / v), with the plant-derived organic fertilizer accounting for 5% of the volume; (6) SPBO10, SPB substrate and plant-derived organic fertilizer were mixed at a ratio of 9:1 (v / v), with the plant-derived organic fertilizer accounting for 10% of the volume; (7) SPBO15, SPB substrate and plant-derived organic fertilizer were mixed at a ratio of 17:3 (v / v), with the plant-derived organic fertilizer accounting for 15% of the volume. All treatments were sterilized at 0.11 MPa and 121℃ before propagation to eliminate interference from other microorganisms. The specific propagation substrates are shown in Table 1:

[0029] Table 1. Ratios of different propagation substrates

[0030]

[0031] Note: In the table, S represents river sand, B represents bentonite, Q represents quartz, P represents perlite, and O represents plant-derived organic fertilizer.

[0032] 4. Inoculation: corn seeds were sterilized with 10% H2O2 for 10 minutes, then soaked in water for 6 hours, and then germinated in an incubator at 27°C. The flowerpots were sterilized with alcohol, and about 750g of substrate was placed in each pot. Each pot was inoculated with 20g of inoculant using a double-layer inoculation method, and each pot contained 3 corn seeds. Each treatment was repeated 5 times. The SB, SP, SQB, and SPB treatments were irrigated with 50% low-phosphorus Hoagland's nutrient solution (phosphorus concentration was 10% of normal Hoagland's nutrient solution, pH 6.45), and the SPBO5, SPBO10, and SPBO15 treatments were irrigated with pure water.

[0033] 5. Nutrient and water management: After the corn emerged, it was watered 2-3 times per week, 200mL per pot each time, and the amount of water was adjusted according to actual conditions. The SB, SP, SQB, and SPB treatments were irrigated with 50% low-phosphorus Hoagland's nutrient solution and pure water alternately, and the SPBO5, SPBO10, and SPBO15 treatments were irrigated with pure water only.

[0034] 6. Propagation completion: After 3 months of propagation, the growth of corn plants was observed, and the mycorrhizal infection rate and spore density of plant roots were detected.

[0035] 7. Test results: The physical and chemical properties of different substrates differed greatly (Table 2). The pH ranged from 8.09 to 9.11, and the effective nitrogen and phosphorus concentrations were at a relatively low level, which was suitable for host plants to recruit AM fungi to form symbionts. After adding plant-derived organic fertilizer, the concentration of organic matter and available nutrients in the substrate was significantly improved.

[0036] Table 2 Physical and chemical properties of different propagation substrates (mean ± standard deviation)

[0037]

[0038]

[0039] Note: S is river sand, B is bentonite, Q is quartz, P is perlite, and O is plant-derived organic fertilizer. Different lowercase letters indicate significant differences in the same chemical index among different substrates (P < 0.05)

[0040] Different substrates had a significant impact on the growth of host plants, corn ( Figure 1 ). With the increase in the proportion of plant-derived organic fertilizer, the growth of corn also increased, and plant-derived organic fertilizer showed a significant promoting effect on the growth of corn plants.

[0041] Table 3 Effect of different propagation substrates on the mycorrhizal infection rate of Cla strain

[0042]

[0043] Note: Data are mean ± standard deviation; different lower case letters indicate significant differences (P < 0.05) in the infection rate index of different substrates.

[0044] As can be seen from Table 3, the propagation effect of the conventional SB substrate is better than that of the SQB substrate, and the propagation effect of the SPB substrate is better than that of the conventional SB substrate; and the infection degree of Claroideoglomus lamellosum in the SPBO15 substrate is the highest. Compared with the conventional SB substrate, the infection intensity of the SPB substrate is increased by 20.69%, and the abundance of the cluster is increased by 86.43%. Compared with the SPB substrate, the propagation effect is not improved, but is reduced by adding 5% and 10% plant source organic fertilizer, but the infection is further improved after adding 15% plant source organic fertilizer, and the infection intensity of the SPBO15 substrate is increased by 12.72% compared with that of the SPB substrate, and the abundance of the cluster is increased by 102.61%.

[0045] As can be seen from Table 3, the propagation effect of the conventional SB substrate is better than that of the SQB substrate, and the propagation effect of the SPB substrate is better than that of the conventional SB substrate; and the infection degree of Claroideoglomus lamellosum in the SPBO15 substrate is the highest. Compared with the conventional SB substrate, the infection intensity of the SPB substrate is increased by 20.69%, and the abundance of the cluster is increased by 86.43%. Compared with the SPB substrate, the propagation effect is not improved, but is reduced by adding 5% and 10% plant source organic fertilizer, but the infection is further improved after adding 15% plant source organic fertilizer, and the infection intensity of the SPBO15 substrate is increased by 12.72% compared with that of the SPB substrate, and the abundance of the cluster is increased by 102.61%. Figure 2 As can be seen from Table 3, the propagation effect of the conventional SB substrate is better than that of the SQB substrate, and the propagation effect of the SPB substrate is better than that of the conventional SB substrate; and the infection degree of Claroideoglomus lamellosum in the SPBO15 substrate is the highest. Compared with the conventional SB substrate, the infection intensity of the SPB substrate is increased by 20.69%, and the abundance of the cluster is increased by 86.43%. Compared with the SPB substrate, the propagation effect is not improved, but is reduced by adding 5% and 10% plant source organic fertilizer, but the infection is further improved after adding 15% plant source organic fertilizer, and the infection intensity of the SPBO15 substrate is increased by 12.72% compared with that of the SPB substrate, and the abundance of the cluster is increased by 102.61%.

[0046] Example 2:

[0047] This example studies the influence of the substrate on different strains:

[0048] 1. Test strains: Claroideoglomus lamellosum strain CXL-18, Rhizophagus intraradices strain Ri, and Acaulospora mellea strain Aca, a total of 3 strains.

[0049] 2. Propagation substrate: SPBO5, SPBO10 and SPBO15.

[0050] 3. Control substrate: SPB.

[0051] 4. Inoculation process: After the corn seeds are disinfected with 10% H2O2 for 10 minutes, they are soaked in water for 6 hours, then germinated in an incubator at 27°C, the flowerpots are disinfected with alcohol, about 750g of substrate is filled in each pot, the inoculation dose is 20g per pot, double-layer inoculation method is used, 3 corn seeds are planted in each pot, and each treatment is repeated 5 times. The SPB treatment is irrigated with 50% low-phosphorus Hoagland nutrient solution (the phosphorus concentration is 10% of the normal Hoagland nutrient solution, and the pH is 6.45), and the SPBO5, SPBO10 and SPBO15 treatments are irrigated with pure water.

[0052] 5. Nutrient and water management: After corn emergence, fixed watering 2-3 times per week, 200 mL per pot each time, adjust the amount of watering according to the actual situation. Among them, the SPB treatment uses 50% low phosphorus Hoagland nutrient solution and pure water alternately, and the SPBO5, SPBO10 and SPBO15 treatments only use pure water irrigation.

[0053] 6. Propagation completion: After 3 months of propagation, the growth of corn plants was observed, and the mycorrhizal infection rate of plant roots was detected. The test results are shown in Table 4.

[0054] Table 4 Effect of different substrates on different strains

[0055]

[0056]

[0057] Note: Data is mean ± standard deviation; different lowercase letters indicate significant differences in infection rate indicators of the same strain in different substrates (P<0.05)

[0058] From Table 4, it can be seen that the infection effect of the layered near bright Glomus CXL-18 under the SPB substrate is the best, and the infection intensity is increased by 25.01% and 62.27% respectively compared with Glomus intraradices Ri and Acauscus Aca. In addition, the mycorrhizal infection rate of different strains also responds differently to plant source organic fertilizer. The mycorrhizal infection rate of Claroideoglomus lamellosum CXL-18 as a whole shows an increasing trend with the increase of the proportion of plant source organic fertilizer, and SPBO15 is the highest, and the infection intensity is increased by 14.28% compared with the SPB control; the mycorrhizal infection rate of Glomus intraradices Ri first increases and then decreases with the increase of the proportion of plant source organic fertilizer, and the infection intensity of SPBO10 is increased by 35.21% compared with the SPB control; the mycorrhizal infection rate of Acauscus Aca decreases with the increase of the proportion of plant source organic fertilizer, and SPBO5 is the highest, and the infection intensity is increased by 24.68% compared with the SPB control.

[0059] Example 3:

[0060] This example studies the effect of different plant source organic fertilizer substrates on strain CXL-18:

[0061] 1. Test strain: Claroideoglomus lamellosum strain CXL-18.

[0062] 2. Propagation substrate: SPB substrate is mixed with plant source organic fertilizer at a ratio of 17:3 (v / v), and the plant source organic fertilizer accounts for 15% of the volume. The plant source organic fertilizer is as shown in test groups 1-4: first, prepare the mixed base material straw: rice straw and corn straw are crushed and mixed at a ratio of 1:1 to obtain the mixed base material straw; the plant source organic fertilizer of test group 1 is prepared as follows: the mixed base material straw is mixed with crushed Astragalus sinicus at a ratio of 1:1, and then is composted at room temperature for 30 days, and then is dried to obtain the Astragalus sinicus plant source organic fertilizer; the plant source organic fertilizer of test group 2 is prepared as follows: the mixed base material straw is mixed with crushed Artemisia selengensis at a ratio of 1:1, and then is composted at room temperature for 30 days, and then is dried to obtain the Artemisia selengensis plant source organic fertilizer; the plant source organic fertilizer of test group 3 is prepared as follows: the mixed base material straw is mixed with crushed sweetleaf chrysanthemum straw at a ratio of 1:1, and then is composted at room temperature for 30 days, and then is dried to obtain the sweetleaf chrysanthemum straw plant source organic fertilizer; and the plant source organic fertilizer of test group 4 is prepared as follows: the mixed base material straw is mixed with crushed soybean straw at a ratio of 1:1, and then is composted at room temperature for 30 days, and then is dried to obtain the soybean straw plant source organic fertilizer.

[0063] 3. Control substrate: SPBO15 (the source of plant source organic fertilizer is the same as that of examples 1-2) and SB.

[0064] 4. Inoculation process: corn seeds are sterilized with 10% H2O2 for 10 minutes, soaked in water for 6 hours, and then germinated in an incubator at 27°C. The flowerpots are sterilized with alcohol, and about 750g of substrate is loaded into each pot. The inoculation dose is 20g per pot, and a double-layer inoculation method is used. Each pot contains 3 corn seeds, and each treatment is repeated 5 times. The SPB treatment is irrigated with 50% low-phosphorus Hoagland nutrient solution (the phosphorus concentration is 10% of the normal Hoagland nutrient solution, and the pH is 6.45), and the propagation substrate of test groups 1-4 and the SPBO15 treatment are irrigated with pure water.

[0065] 5. Nutrient and water management: After the corn seedlings emerge, they are watered 2-3 times per week, with 200mL per pot each time. The amount of water is adjusted according to actual conditions. The SPB treatment is irrigated with 50% low-phosphorus Hoagland nutrient solution and pure water alternately, and the propagation substrate of test groups 1-4 and the SPBO15 treatment are irrigated with pure water.

[0066] 6. Propagation completion: after 3 months of propagation, the growth of corn plants is observed, and the mycorrhizal infection rate of plant roots is detected. The test results are shown in Table 5.

[0067] Table 5 Influence of different plant source substrates on Cla strain

[0068]

[0069] From the infection intensity, SPBO15 > test group 3 > test group 2 > SPB > test group 1 > test group 4; from the abundance of the cluster, SPBO15 > test group 3 > test group 2 > SPB > test group 1 > test group 4; and, test group 3 and test group 2 are not significantly different, SPBO15 and test group 3 and test group 2 are significantly different, the infection intensity of SPB and test group 1 are not significantly different, and test group 4 is significantly different, which shows that different plant source organic fertilizers have different effects on the growth of the strain, the plants used in the embodiment are relatively single, and the nutritional components are not uniform. In order to further study the influence of plant source organic fertilizers of different sources on the strain CXL-18, it is considered to mix a plurality of plants of different sources to prepare the organic fertilizer. Therefore, according to the experimental results in Table 5, the plant source fertilizers of test group 2 and test group 3 are selected for different proportions, and the influence of the plant source substrate on the Cla strain under different proportions is studied, as follows:

[0070] 1. Test strain: Claroideoglomus lamellosum strain CXL-18.

[0071] 2. Control substrate: SPBO15 (the source of the plant source organic fertilizer is consistent with that of Example 1-2);

[0072] 3. Propagation substrate: SPB substrate and plant source organic fertilizer are mixed according to 17:3 (v / v), and the volume ratio of the plant source organic fertilizer is 15%. The preparation method of the plant source organic fertilizer is as follows: first, prepare mixed base material straw: rice straw and corn straw are crushed and mixed according to 1:1 to obtain; then, mix the mixed base material straw with crushed different proportions of Artemisia sacrorum straw-leafy chrysanthemum straw plant source organic fertilizer according to the proportions in Table 6 to obtain the corresponding Artemisia sacrorum straw-leafy chrysanthemum straw organic fertilizer:

[0073] Table 6 Different proportions of Artemisia sacrorum straw-leafy chrysanthemum straw plant source organic fertilizer

[0074]

[0075]

[0076] The preparation method of the plant source organic fertilizer in the above tests A-E is as follows:

[0077] (1) First, prepare mixed base material straw: rice straw and corn straw are crushed and mixed according to 1:1 to obtain;

[0078] (2) Prepare Artemisia sacrorum straw-leafy chrysanthemum straw: crush Artemisia sacrorum straw or leafy chrysanthemum straw, and mix according to the mass ratio in Table 6;

[0079] (1) The mixed base material straw and reed stalk-chenopodium zollingeri straw of step (1) are mixed according to a mass ratio of 1:1 to obtain a corresponding plant source organic fertilizer.

[0080] 4. Inoculation process: after the corn seeds are disinfected with 10% H2O2 for 10 minutes, soaked in water for 6 hours, and then germinated in an incubator at 27°C, the flowerpots are disinfected with alcohol, about 750g of the substrate is loaded into each pot, the inoculation dose of each pot is 20g, double-layer inoculation is adopted, 3 corn seeds are inoculated in each pot, and each treatment is repeated 5 times; the propagation substrate of test groups A-E and the SPBO15 treatment are irrigated with pure water.

[0081] 5. Nutrient and water management: after the corn sprouts, water is fixed 2-3 times per week, 200mL per pot each time, and the amount of water is adjusted according to the actual situation; the propagation substrate of test groups A-E and the SPBO15 treatment are irrigated with pure water.

[0082] 6. Propagation completion: after 3 months of propagation, the growth of corn plants is observed, and the mycorrhizal infection rate of plant roots is detected. The test results are shown in Table 7.

[0083] Table 7 Influence of different plant source substrates on the strain Cla

[0084]

[0085] As shown in Table 7, the propagation capacity of test B and test C is similar to that of SPBO15, and the difference is not significant; and it is significantly higher than that of test A, test D and test E, which shows that when different plant sources are mixed to prepare organic fertilizer, due to the difference in the nutritional components of plants, different proportions have a great influence on the strain, therefore, for the plant source organic fertilizer of reed stalk and chenopodium zollingeri straw, when the mass ratio of reed stalk plant source organic fertilizer and chenopodium zollingeri straw plant source organic fertilizer is 1-2:2-3, the propagation effect on the strain CXL-18 is the best.

[0086] In summary, the application is a culture substrate designed according to the strain of Glomus lamellosum, which has the technical advantages of good and stable propagation effect on the strain of Glomus lamellosum, and the propagation effect of the substrate is better than that of all commercially available substrates, which can provide a broader application prospect for the rapid propagation of the dominant strain CXL-18.

[0087] The above description is a detailed description of the preferred and feasible embodiments of the application, but the embodiments are not used to limit the scope of the patent application of the application, and any equivalent changes or modifications completed under the technical spirit of the application should belong to the patent scope covered by the application.

Claims

1. Lamella near-luminiferous globosum ( Claroideoglomus lamellosum The propagation substrate of the strain is characterized by, The propagation substrate is mixed by SPB substrate and plant source organic fertilizer according to the volume ratio of 17:3; the SPB substrate is mixed by river sand, perlite and bentonite according to the volume ratio of 6:3:1, and the plant source organic fertilizer is reed stalk plant source organic fertilizer and / or sweet leaf chrysanthemum straw plant source organic fertilizer 。 2. A matrix for the propagation of the strain of the laminar, nearly globose Glomus (Glomus lamatum) according to claim 1, characterised in that it comprises: Claroideoglomus lamellosum The layered near-observable globosum ( Claroideoglomus lamellosum The strain is CXL-18, and its preservation number is CGMCC NO.40331. ​ 3. A method of preparing a propagation substrate according to either of claims 1 or 2, characterised in that, The method is: (1) prepare plant source organic fertilizer for standby; (2) mix river sand, perlite and bentonite according to the volume ratio of 6:3:1 to obtain SPB substrate; (3) mix the plant source organic fertilizer of step (1) and the SPB substrate of step (2) according to the volume ratio of 17:3 to obtain.

4. The propagation substrate produced by the method of claim 3, wherein, The pH of the propagation substrate is 8.61±0.04, the conductivity is 932.41±19.06 μs / cm, the organic matter is 32.31±2.98 g / kg, the available nitrogen is 78.75±21.86 mg / kg, the available phosphorus is 18.74±1.73 mg / kg, the available potassium is 562.81±38.71 mg / kg, the available calcium is 1422.69±48.85 mg / kg, the available magnesium is 198.73±5.20 mg / kg, the available iron is 19.86±2.29 mg / kg, the available manganese is 8.81±0.37 mg / kg, the available copper is 0.89±0.15 mg / kg, and the available zinc is 5.90±0.76 mg / kg.

5. The propagation substrate of claim 1, wherein, The mass ratio of the reed stem plant source organic fertilizer and the stevia stem plant source organic fertilizer is 1-2:2-3.

6. The propagation substrate of claim 5, wherein, The preparation method of the reed stem plant source organic fertilizer and / or the stevia stem plant source organic fertilizer is: (1) first prepare mixed base straw: rice straw and corn straw are crushed and mixed according to the ratio of 1:1 to obtain; (2) prepare reed stem- stevia stem: reed stems and stevia stems are crushed and mixed according to the corresponding mass ratio to obtain; (3) mix the mixed base straw of step (1) and the reed stem- stevia stem, and then pile up at room temperature for 30 days, and then dry to obtain the corresponding plant source organic fertilizer.

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