Microbial complex microbial inoculant for improving drought resistance of corn and application of microbial complex microbial inoculant

Abstract

The invention provides a microbial complex microbial inoculant for improving drought resistance of corn and application of the microbial complex microbial inoculant, and belongs to the technical field of microbial inoculants. The composite microbial agent is prepared from the following raw materials in parts by weight: 6 to 10 parts of an arbuscular mycorrhizal fungus agent, 2 to 4 parts of bacillus thuringiensis powder, 2 to 4 parts of bacillus subtilis powder, 2 to 4 parts of bacillus pumilus powder, 4 to 6 parts of bacillus amyloliquefaciens powder and 6 to 10 parts of bacillus pseudomycoides powder. According to the invention, a plurality of microbial strains with different functions are combined, the synergistic effect of the microbial strains is exerted, the microenvironment of a corn root system is improved together, the growth and development of corn are promoted, and the drought resistance of corn is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of microbial agents, and in particular relates to a microbial composite agent for improving the drought resistance of corn and an application thereof. Background Art

[0002] As an important global crop for food, feed, and industrial production, corn plays a crucial role in ensuring food security and promoting agricultural economic development. However, with the intensification of global climate change, drought stress has become one of the main environmental factors restricting corn yield and quality. Drought can lead to slow plant growth, poor root development, leaf wilting, and reduced photosynthesis, which in turn affects grain filling and grain formation, resulting in severe yield losses. Therefore, improving corn's drought resistance is of great practical significance for ensuring stable corn production and sustainable agricultural development.

[0003] At present, the methods to improve the drought resistance of corn mainly include variety selection, agricultural measures and chemical regulation. In terms of variety selection, some corn varieties with certain drought resistance have been bred through conventional hybrid breeding and modern biotechnology. However, the breeding cycle is long, the cost is high, and the genetic mechanism of drought resistance is complex, making it difficult to achieve breakthrough progress in a short period of time. Agricultural measures such as reasonable irrigation, mulching to retain moisture, and balanced fertilization can alleviate the effects of drought stress to a certain extent, but they are difficult to promote and apply on a large scale due to water shortages and geographical conditions. Chemical regulation methods mainly improve the physiological metabolism and water use efficiency of corn by applying chemical substances such as drought-resistant agents and growth regulators. However, the long-term use of chemical agents may pose potential risks to the soil environment and the quality and safety of agricultural products.

[0004] Although some microorganisms can improve soil structure and nutrient supply, promote root development, and enhance maize drought resistance by forming symbiotic relationships with plant roots or colonizing around them, most current research focuses on the effects of single microbial agents on maize drought resistance. The functions of a single strain are relatively limited, making it difficult to fully meet the growth requirements of maize under drought stress. Synergistic or antagonistic interactions may exist between different microorganisms, and the application of a single strain may not fully leverage the combined effects of the microbial community. Furthermore, the complex and variable soil environment may limit the colonization and stress resistance of a single microbial agent, resulting in unstable results in practical applications. Therefore, the development of composite agents that can improve maize drought resistance is particularly necessary. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a microbial composite agent for improving the drought resistance of corn and its application. The present invention rationally combines multiple microbial strains with different functions to exert their synergistic effects, jointly improve the corn root microenvironment, promote corn growth and development, and improve corn drought resistance.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The invention provides a microbial composite agent for improving the drought resistance of corn. The microbial composite agent comprises the following raw materials in parts by weight: 6-10 parts of arbuscular mycorrhizal fungal agent, 2-4 parts of Bacillus thuringiensis powder, 2-4 parts of Bacillus subtilis powder, 2-4 parts of Bacillus pumilus powder, 4-6 parts of Bacillus amyloliquefaciens powder, and 6-10 parts of Bacillus pseudomycoides powder.

[0008] Preferably, the microbial composite agent comprises the following raw materials in parts by weight: 7 to 9 parts of arbuscular mycorrhizal fungal agent, 2.5 to 3.5 parts of Bacillus thuringiensis powder, 2.5 to 3.5 parts of Bacillus subtilis powder, 2.5 to 3.5 parts of Bacillus pumilus powder, 4.5 to 5.5 parts of Bacillus amyloliquefaciens powder, and 7 to 9 parts of Bacillus pseudomycoides powder.

[0009] Preferably, the microbial composite agent comprises the following raw materials in parts by weight: 8 parts of arbuscular mycorrhizal fungi agent, 3 parts of Bacillus thuringiensis powder, 3 parts of Bacillus subtilis powder, 3 parts of Bacillus pumilus powder, 5 parts of Bacillus amyloliquefaciens powder, and 8 parts of Bacillus pseudomycoides powder.

[0010] The present invention provides a method for preparing the microbial composite agent. The microbial composite agent is obtained by mixing arbuscular mycorrhizal fungal agent, Bacillus thuringiensis powder, Bacillus subtilis powder, Bacillus pumilus powder, Bacillus amyloliquefaciens powder and Bacillus pseudomycoides powder according to parts by weight.

[0011] The present invention also provides the use of the microbial composite agent or the microbial composite agent obtained according to the preparation method in preparing a product for improving the drought resistance of corn.

[0012] Preferably, the product is a seed soaking agent or a fertilizer.

[0013] Preferably, the preparation method of the seed soaking agent is to mix the composite bacterial agent with water to prepare a bacterial liquid, which is used for soaking corn seeds;

[0014] The mass volume ratio of the composite bacterial agent to water is 1g:300-400mL.

[0015] Preferably, the seed soaking time is 8 to 12 hours.

[0016] Preferably, the fertilizer is prepared by mixing the composite bacterial agent with water to prepare a bacterial solution, which is used for root irrigation of corn;

[0017] The mass volume ratio of the composite bacterial agent to water is 1g:100-200mL.

[0018] Preferably, the amount of corn root irrigation is 40 to 60 mL per plant.

[0019] Compared with existing technologies, the present invention has the following beneficial effects: by rationally combining multiple microbial strains with different functions and leveraging their synergistic effects, the present invention improves the corn root microenvironment, promotes corn growth and development, and enhances corn drought resistance. The present microbial composite agent has the advantages of being environmentally friendly, highly efficient, and highly adaptable. It can provide a new and effective approach to drought-resistant corn production and has broad application prospects. DETAILED DESCRIPTION

[0020] The present invention provides a microbial composite agent for improving the drought resistance of corn. The microbial composite agent comprises the following raw materials in parts by weight:

[0021] 6 to 10 parts of arbuscular mycorrhizal fungi agent, preferably 7 to 9 parts, more preferably 8 parts;

[0022] 2 to 4 parts, preferably 2.5 to 3.5 parts, more preferably 3 parts, of Bacillus thuringiensis powder;

[0023] 2 to 4 parts, preferably 2.5 to 3.5 parts, more preferably 3 parts, of Bacillus subtilis powder;

[0024] 2 to 4 parts, preferably 2.5 to 3.5 parts, more preferably 3 parts, of Bacillus pumilus powder;

[0025] 4 to 6 parts of Bacillus amyloliquefaciens powder, preferably 4.5 to 5.5 parts, more preferably 5 parts;

[0026] 6 to 10 parts, preferably 7 to 9 parts, more preferably 8 parts, of Bacillus mycoides powder.

[0027] In the present invention, the arbuscular mycorrhizal fungi in the arbuscular mycorrhizal fungal agent can secrete glycoproteins to bind to soil particles, promote the formation of microaggregates, increase soil porosity and water holding capacity, and alleviate compaction;

[0028] The Bacillus thuringiensis in Bacillus thuringiensis powder can effectively reduce insect pests, reduce leaf damage rate, and indirectly reduce plant water loss. In addition, Bacillus thuringiensis can secrete plant hormones or enzymes to stimulate the growth of lateral roots and increase the root surface area.

[0029] The Bacillus subtilis in Bacillus subtilis powder can secrete indoleacetic acid, gibberellins, cytokinins, etc., which promote root development and aboveground growth; the exopolysaccharides produced by the strain metabolism can bind to soil particles, promote the formation of aggregate structure, increase soil porosity and water holding capacity, and alleviate drought;

[0030] The indolebutyric acid and cytokinins secreted by Bacillus pumilus in the bacterial powder can promote the elongation of the main root and the differentiation of lateral roots. The brassinolide analogues in the strain's metabolites can reduce leaf stomatal conductance, reduce water transpiration, and promote the expression of root aquaporins, improving water absorption efficiency and achieving the purpose of drought resistance.

[0031] The indoleacetic acid and cytokinin secreted by Bacillus amyloliquefaciens in the powder of Bacillus amyloliquefaciens can promote the differentiation of lateral root primordia. In addition, under drought conditions, Bacillus amyloliquefaciens can achieve the purpose of drought resistance by inducing plants to accumulate osmotic protective substances.

[0032] The Bacillus pseudomycoides in Bacillus pseudomycoides powder can secrete indoleacetic acid and gibberellins, which directly promote the growth of plant roots and enhance the root absorption capacity; the brassinolide analogues secreted by Bacillus pseudomycoides can reduce the stomatal conductance of leaves and reduce water transpiration, while promoting the expression of root water channel proteins, improving water absorption efficiency, and achieving the purpose of drought resistance.

[0033] In the present invention, a variety of microbial strains with different functions are rationally combined to exert their synergistic effects, thereby jointly improving the corn root microenvironment, promoting corn growth and development, and improving corn drought resistance.

[0034] The present invention provides a method for preparing the microbial composite agent. The microbial composite agent is obtained by mixing arbuscular mycorrhizal fungal agent, Bacillus thuringiensis powder, Bacillus subtilis powder, Bacillus pumilus powder, Bacillus amyloliquefaciens powder and Bacillus pseudomycoides powder according to parts by weight.

[0035] The present invention also provides the use of the microbial composite agent or the microbial composite agent obtained according to the preparation method in the preparation of a product for improving the drought resistance of corn.

[0036] In the present invention, the product is a seed soaking agent or a fertilizer.

[0037] In the present invention, the preparation method of the seed soaking agent is to mix the composite bacterial agent with water to prepare a bacterial liquid for soaking corn seeds; the mass volume ratio of the composite bacterial agent to water is 1g:300~400mL, preferably 1g:330~380mL, and more preferably 1:350mL, and the soaking time is 8~12h, preferably 9~11h, and more preferably 10h.

[0038] In the present invention, the preparation method of the fertilizer is to mix the composite bacterial agent with water to prepare a bacterial liquid, which is used for root irrigation of corn; the mass volume ratio of the composite bacterial agent to water is 1g:100-200mL, preferably 120-180mL, and more preferably 150mL, and the amount of the corn root irrigation is 40-60mL / plant, preferably 45-55mL / plant, and more preferably 50mL / plant.

[0039] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0040] Among the microbial composite agents, arbuscular mycorrhizal fungi were purchased from Beijing Jinbilai Biotechnology Co., Ltd., Bacillus thuringiensis powder was purchased from Wuhan Plov Biotechnology Co., Ltd., Bacillus subtilis powder was purchased from Wuhan Plov Biotechnology Co., Ltd., Bacillus pumilus powder was purchased from Weifang Ruichen Biotechnology Co., Ltd., Bacillus amylolyticus powder was purchased from Weifang Ruichen Biotechnology Co., Ltd., and Bacillus pseudomycoides powder was purchased from Shanghai Xuanke Biotechnology Co., Ltd.

[0041] Example 1

[0042] Raw materials were weighed according to the mass ratio of 8 parts of arbuscular mycorrhizal fungal agent, 3 parts of Bacillus thuringiensis powder, 3 parts of Bacillus subtilis powder, 3 parts of Bacillus pumilus powder, 5 parts of Bacillus amyloliquefaciens powder and 8 parts of Bacillus pseudomycoides powder, and the mixture was mixed to obtain a microbial composite agent.

[0043] Example 2

[0044] Raw materials were weighed according to the mass ratio of 6 parts of arbuscular mycorrhizal fungal agent, 4 parts of Bacillus thuringiensis powder, 4 parts of Bacillus subtilis powder, 4 parts of Bacillus pumilus powder, 6 parts of Bacillus amyloliquefaciens powder and 6 parts of Bacillus pseudomycoides powder, and the raw materials were mixed to obtain a microbial composite agent.

[0045] Example 3

[0046] Raw materials were weighed according to the mass ratio of 10 parts of arbuscular mycorrhizal fungal agent, 2 parts of Bacillus thuringiensis powder, 2 parts of Bacillus subtilis powder, 2 parts of Bacillus pumilus powder, 4 parts of Bacillus amyloliquefaciens powder and 10 parts of Bacillus pseudomycoides powder, and the mixture was mixed to obtain a microbial composite agent.

[0047] Comparative Example 1

[0048] Raw materials were weighed according to the mass ratio of 12 parts of arbuscular mycorrhizal fungal agent, 1 part of Bacillus thuringiensis powder, 1 part of Bacillus subtilis powder, 1 part of Bacillus pumilus powder, 7 parts of Bacillus amyloliquefaciens powder and 8 parts of Bacillus pseudomycoides powder, and the mixture was mixed to obtain a microbial composite agent.

[0049] Comparative Example 2

[0050] Raw materials were weighed according to the mass ratio of 5 parts of arbuscular mycorrhizal fungal agent, 3 parts of Bacillus thuringiensis powder, 3 parts of Bacillus subtilis powder, 3 parts of Bacillus pumilus powder, 5 parts of Bacillus amyloliquefaciens powder and 11 parts of Bacillus pseudomycoides powder, and the mixture was mixed to obtain a microbial composite agent.

[0051] Comparative Example 3

[0052] The microbial composite agent was obtained in the same manner as in Example 1, except that the arbuscular mycorrhizal fungal agent was replaced with a DSE agent (provided by the Institute of Microbiology, Guangxi Academy of Agricultural Sciences).

[0053] Comparative Example 4

[0054] The microbial composite agent was obtained in the same manner as in Example 1, except that the Bacillus subtilis powder was replaced with Trichoderma harzianum powder (purchased from Weifang Ruichen Biotechnology Co., Ltd.).

[0055] Comparative Example 5

[0056] The microbial composite agent was obtained in the same manner as in Example 1, except that the pseudomycoides powder was not used, and the amount of pseudomycoides powder was supplemented by an arbuscular mycorrhizal fungal agent.

[0057] Comparative Example 6

[0058] The microbial composite agent was obtained in the same manner as in Example 1, except that the arbuscular mycorrhizal fungus agent was not used, and the amount of the arbuscular mycorrhizal fungus agent was supplemented by Bacillus pseudomycoides powder.

[0059] Experimental Example 1

[0060] The microbial composite agents obtained in Examples 1-3 and Comparative Examples 1-6 were dissolved in water at a mass-to-volume ratio of 1 g:350 mL to obtain different soaking solutions. Corn Zhengdan 958 seeds were soaked in the different soaking solutions for 10 hours before sowing. The effects of soaking with the different soaking solutions on corn germination and later seedling drought resistance were examined. Clear water was used as a control.

[0061] Four soil moisture levels (mass moisture content of 20%, 13%, 8%, and 5%) were designed, with a 14-hour light and 10-hour dark period. Soil moisture was calculated as mass percentage (absolute soil moisture content). Soaked corn Zhengdan 958 seeds (50 seeds per group) were placed in soil of the corresponding moisture content, with the embryo facing upward and the seed spacing maintained. Fifteen days after sowing, the number of germinated seeds was recorded. Corn seedlings were uprooted from the soil and cut at the base of the stem. Seedling length and root length were measured. The results are shown in Tables 1 and 2.

[0062] Table 1 Effect of different soaking solutions on corn germination rate (%)

[0063]

[0064]

[0065] Table 2 Effects of different soaking solutions on the seedling length and root length of corn seedlings (cm)

[0066]

[0067] As shown in Tables 1 and 2, when the soil moisture content dropped from 20% (suitable soil moisture content) to 5% (severe drought), the germination rate of corn seeds in the control group dropped from 100% to 80%, and the seedling length and root length of corn seedlings dropped from 14.52cm and 15.13cm to 11.72cm and 11.81cm, respectively. This shows that even drought-resistant varieties will have a significantly decreased seed germination rate in severely arid areas, but after soaking seeds with the microbial composite inoculant of the present invention, there was no significant decrease in germination rate. And as shown in Table 2, after soaking seeds with the microbial composite inoculant of the present invention, the seedling length and root length of corn seedlings can be increased, allowing corn to grow normally in arid areas.

[0068] Experimental Example 2

[0069] The microbial composite agents obtained in Examples 1 to 3 and Comparative Examples 1 to 6 were dissolved in water at a mass volume ratio of 1 g:150 mL to obtain different fertilizers.

[0070] 50 collected Zhengdan 958 corn seeds were immersed in 75% ethanol for 2 min, rinsed with clean water for 5 min, and the sterilized corn seeds were sown in a basin with sand as the medium (1 seed / basin). The sand was moistened with clean water in 50 mL / basin. After 10 days of seedling emergence, 33 corn seedlings with consistent growth conditions were selected and randomly divided into 11 groups. Among them, 10 groups were added with 20% (W / V) polyethylene glycol 6000 solution in 50 mL / basin to the corn seedlings. After 3 days, different fertilizers were added in an amount of 50 mL / plant. 1 to 3 groups were respectively added to the fertilizer prepared by the microbial composite agent obtained in Examples 1 to 3, 4 to 9 groups were respectively added to the fertilizer prepared by the microbial composite agent obtained in Comparative Examples 1 to 6, and 10 groups were added to clean water (control group). Another group did not do any treatment, and only added clean water of equal quality when adding polyethylene glycol and fertilizer (blank group). After 7 days, the fresh weight of the plants was weighed to evaluate the effects of different fertilizers on the plants under drought conditions. The results are shown in Table 3.

[0071] Table 3 Effects of different fertilizers on plant fresh weight (g / plant)

[0072]

[0073] As shown in Table 3, the microbial composite agent of the present invention can effectively alleviate the impact of drought on plants, indicating that the microbial composite agent of the present invention can effectively improve the drought resistance of corn when used as a fertilizer.

[0074] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A microbial composite agent for improving drought resistance of corn, characterized in that: The microbial composite agent comprises the following raw materials in parts by weight: 6 to 10 parts of arbuscular mycorrhizal fungal agent, 2 to 4 parts of Bacillus thuringiensis powder, 2 to 4 parts of Bacillus subtilis powder, 2 to 4 parts of Bacillus pumilus powder, 4 to 6 parts of Bacillus amyloliquefaciens powder, and 6 to 10 parts of Bacillus pseudomycoides powder.

2. The microbial composite agent according to claim 1, characterized in that The microbial composite agent comprises the following raw materials in parts by weight: 7 to 9 parts of arbuscular mycorrhizal fungal agent, 2.5 to 3.5 parts of Bacillus thuringiensis powder, 2.5 to 3.5 parts of Bacillus subtilis powder, 2.5 to 3.5 parts of Bacillus pumilus powder, 4.5 to 5.5 parts of Bacillus amyloliquefaciens powder, and 7 to 9 parts of Bacillus pseudomycoides powder.

3. The microbial composite agent according to claim 2, characterized in that The microbial composite agent comprises the following raw materials in parts by weight: 8 parts of arbuscular mycorrhizal fungal agent, 3 parts of Bacillus thuringiensis powder, 3 parts of Bacillus subtilis powder, 3 parts of Bacillus pumilus powder, 5 parts of Bacillus amyloliquefaciens powder, and 8 parts of Bacillus pseudomycoides powder.

4. The method for preparing the microbial composite agent according to any one of claims 1 to 3, characterized in that: The microbial composite agent is obtained by mixing arbuscular mycorrhizal fungal agent, Bacillus thuringiensis powder, Bacillus subtilis powder, Bacillus pumilus powder, Bacillus amyloliquefaciens powder and Bacillus pseudomycoides powder according to weight parts.

5. Use of the microbial composite agent according to any one of claims 1 to 3 or the microbial composite agent obtained according to the preparation method according to claim 4 in the preparation of a product that improves the drought resistance of corn.

6. The use according to claim 5, characterized in that The product is a seed soaking agent or a fertilizer.

7. The use according to claim 6, characterized in that The preparation method of the seed soaking agent is as follows: the composite bacterial agent is mixed with water to prepare a bacterial liquid, which is used for soaking corn seeds; The mass volume ratio of the composite bacterial agent to water is 1g:300-400mL.

8. The use according to claim 7, characterized in that The seed soaking time is 8 to 12 hours.

9. The use according to claim 6, characterized in that The preparation method of the fertilizer comprises the following steps: mixing the composite bacterial agent with water to prepare a bacterial solution, which is used for root irrigation of corn; The mass volume ratio of the composite bacterial agent to water is 1g:100-200mL.

10. The use according to claim 10, characterized in that The amount of the corn root irrigation is 40 to 60 mL per plant.

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