A growth-promoting and stress-resistant agent containing polyaspartic peptide and its preparation method

Abstract

This invention relates to the field of agricultural biotechnology, and particularly to a growth-promoting and stress-resistant agent containing polyaspartic peptides and its preparation method. The raw materials of the plant growth-promoting and stress-resistant agent, by weight, include the following: 450-550 parts deionized water, 50-70 parts modified polyaspartic acid, 10-20 parts compound functional microbial agent, 10-20 parts potassium humate, 4-8 parts betaine, 2-6 parts neutral silicon, 0.5-1.5 parts sodium alginate, and 2-4 parts calcium chloride. The growth-promoting and stress-resistant agent of this invention has good growth-promoting and stress-resistant effects, and the microorganisms contained therein survive more stably.

Description

Technical Field

[0001] This invention relates to the field of agricultural biotechnology, and in particular to a growth-promoting and stress-resistant agent containing polyaspartic peptides and its preparation method. Background Technology

[0002] With the intensification of global climate change, abiotic and biotic stresses such as extreme heat, freezing damage, seasonal drought, soil salinization, and frequent soil-borne diseases have become core limiting factors restricting the improvement of global crop yields and quality. According to statistics from the Food and Agriculture Organization of the United Nations (FAO), more than 60% of global crop yield losses are directly caused by abiotic stresses, with drought, salinity, and extreme temperature stress causing yield reductions of more than 50% of the potential crop yield. my country currently has approximately 99.13 million hectares of salinized land, and arid and semi-arid regions account for 52.5% of the total land area. Coupled with soil acidification, secondary salinization, and accumulation of soil-borne pathogens caused by long-term continuous cropping in greenhouse cultivation, the risk of compound stresses on crops in agricultural production continues to rise, posing a severe challenge to ensuring stable agricultural production and supply.

[0003] Meanwhile, agriculture is at a critical stage of green and high-quality transformation, and reducing the use of chemical fertilizers and pesticides while increasing their efficiency has become a rigid requirement for sustainable agricultural development. Traditional agricultural production relies heavily on excessive fertilizer input to increase crop yields, chemical pesticides to combat biological stress, and exogenous plant growth regulators to regulate growth. This model not only easily leads to a series of problems such as soil compaction and degradation, agricultural non-point source pollution, and excessive pesticide residues in agricultural products, but also generally suffers from inherent defects such as single function, limited stress resistance effects, and susceptibility to phytotoxicity and environmental risks. Currently available products related to promoting growth and stress resistance can be mainly divided into four categories: chemically synthesized plant growth regulators, microbial inoculants, amino acid / humic acid functional fertilizers, and natural plant extracts. While each type of product has achieved certain application effects in specific scenarios, it still cannot meet the core needs of modern agriculture for broad-spectrum, efficient, safe, and stable products that promote growth and stress resistance. Currently, researchers have conducted extensive studies on growth-promoting and stress-resistant agents. For example, patent number CN120230686B discloses "a stress-resistant and growth-promoting microbial agent and its preparation method and application," which contains Bacillus sicca, Burkholderia bifidum, and Sphingomonas yunnanensis. When the bacterial solutions of the three strains are mixed in equal proportions, they work synergistically to significantly improve the stress-resistant and growth-promoting effects, especially in improving stress resistance indicators during the growth process of wheat plants. This is manifested in increasing the activity of the antioxidant enzyme SOD, increasing the content of the osmotic regulator proline, and reducing the content of MDA in the plants. When combined with conventional fertilization, this microbial agent significantly promotes the growth of wheat seedlings under salt stress and increases wheat yield.

[0004] However, microbial agents are easily deactivated by environmental factors during storage, which reduces the effectiveness of growth promoters and stress-resistant agents. Therefore, there is an urgent need to develop a growth promoter and stress-resistant agent containing polyaspartic acid peptides and in which the microbial agent is stable during storage. Summary of the Invention

[0005] The purpose of this invention is to provide a growth-promoting and stress-resistant agent containing polyaspartic acid polypeptide and its preparation method, so as to solve the problems of unstable storage and easy inactivation of microbial agents in current growth-promoting and stress-resistant agents, and the lack of lasting effect.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a plant growth promoter and stress-resistant agent containing polyaspartic acid polypeptide and its preparation method. The plant growth promoter and stress-resistant agent comprises the following raw materials by weight: 450-550 parts deionized water, 50-70 parts modified polyaspartic acid, 10-20 parts compound functional bacterial agent, 10-20 parts potassium humate, 4-8 parts betaine, 2-6 parts neutral silicon, 0.5-1.5 parts sodium alginate, and 2-4 parts calcium chloride.

[0007] This application is prepared using deionized water, modified polyaspartic acid, compound functional microbial agent, potassium humate, betaine, neutral silicon and sodium alginate as raw materials. The microbial agent in this growth promoter and stress resistant agent is more stable to store, and at the same time, this growth promoter and stress resistant agent has a slow-release effect and can promote plant growth for a long time.

[0008] In some embodiments, the modified polyaspartic acid is obtained by covalently grafting ε-polylysine amidation into the polyaspartic acid structure.

[0009] In some embodiments, the preparation method of the modified polyaspartic acid includes the following steps: S1. Add polyaspartic acid to phosphate buffer, then add EDC and NHS to make a mixed solution; S2. Add ε-polylysine to the mixed solution obtained in step S1 and mix. Adjust the pH of the system to 7.2-7.4 and stir at room temperature in the dark for 10-14 hours. After the reaction is completed, dialyze the reaction solution through a dialysis bag for 70-74 hours and freeze-dry to obtain modified polyaspartic acid.

[0010] This application obtains modified polyaspartic acid by covalently grafting ε-polylysine into the polyaspartic acid structure via acid amidation. The modified polyaspartic acid carries both anionic carboxyl groups and cationic amino groups as amphoteric polyelectrolytes. The cationic amino groups of ε-polylysine can be stably bound to the anionic phospholipid bilayer and peptidoglycan layer on the surface of the functional bacterial cell membrane through electrostatic adsorption, forming a stable "polymer-bacterial cell" complex before spray drying, thus avoiding the separation of the bacterial cells and the carrier during atomization and drying.

[0011] In addition, modified polyaspartic acid possesses excellent ion chelating and pH buffering capabilities, enabling it to rapidly chelate Na+ in soil under saline-alkali conditions. + CO3 2- HCO3 - The presence of salt and alkali ions creates a buffer microenvironment within the microspheres that isolates the bacteria from extreme external stresses. In arid environments, the hydrophilic groups of modified polyaspartic acid can lock in a large amount of water, preventing protein denaturation, nucleic acid damage, and cell membrane rupture caused by cell dehydration, thus fundamentally solving the problem of rapid bacterial inactivation under adverse conditions.

[0012] In some embodiments, the mass ratio of polyaspartic acid to ε-polylysine is 1:(0.4~0.8).

[0013] Preferably, the mass ratio of polyaspartic acid to ε-polylysine is 1:0.6.

[0014] This application, by adjusting the mass ratio of polyaspartic acid and ε-polylysine, can ensure the grafting rate while avoiding excessive intermolecular cross-linking that would affect water retention capacity.

[0015] In some embodiments, the number-average molecular weight of the polyaspartic acid is 15-25 kDa.

[0016] Preferably, the polyaspartic acid has a number-average molecular weight of 20 kDa.

[0017] By selecting polyaspartic acid with a specific number-average molecular weight, this application can avoid nozzle clogging during subsequent processing and also prevent the microspheres from having defects in their shells, which could lead to breakage during transportation.

[0018] In some embodiments, the pH of the phosphate buffer solution is 7 to 8.

[0019] Preferably, the pH of the phosphate buffer solution is 7.2.

[0020] In some embodiments, the mass ratio of EDC and NHS in step S2 to polyaspartic acid in step S1 is (1.5~2):(0.4~0.8):1.

[0021] Preferably, the mass ratio of EDC and NHS in step S2 to polyaspartic acid in step S1 is 1.7:0.6:1.

[0022] In some embodiments, the composite functional microbial agent includes Bacillus subtilis bacterial solution, Bacillus megaterium bacterial solution, Bacillus mucilaginosus bacterial solution, and Nostoc commune algae solution.

[0023] In some embodiments, the volume ratio of the Bacillus subtilis bacterial solution, Bacillus megaterium bacterial solution, Bacillus mucilaginosus bacterial solution, and Nostoc commune bacterial solution is 1:(0.4~0.6):(0.4~0.6):(0.6~0.8); the OD of the Bacillus subtilis bacterial solution is... 600 The OD value of Bacillus megaterium culture was 0.3~0.8. 600 The OD value of Bacillus mucilaginosus bacterial culture is 0.2~0.6. 600 The OD value of the Nostoc commune solution was 0.4~0.8. 600 The value is 0.3~0.7.

[0024] Preferably, the volume ratio of the Bacillus subtilis bacterial solution, Bacillus megaterium bacterial solution, Bacillus mucilaginosus bacterial solution, and Nostoc commune bacterial solution is 1:0.5:0.5:0.7; the OD of the Bacillus subtilis bacterial solution is... 600 The value is 0.5, indicating the OD value of Bacillus megaterium culture. 600 The value is 0.4, indicating the OD value of Bacillus mucilaginosus bacterial culture. 600 The value is 0.6, indicating the OD value of the Nostoc commune solution. 600 The value is 0.5.

[0025] Another aspect of the present invention provides a method for preparing a growth-promoting and stress-resistant agent containing polyaspartic peptides, comprising the following steps: (1) Mix modified polyaspartic acid with 75-80% by weight of deionized water, and add 75-85% by weight of sodium alginate to obtain mixture A; (2) Mix the compound functional microbial agent with 45-55% by weight of betaine to obtain mixture B; (3) Mix the mixture A obtained in step (1) with the mixture B obtained in step (2), add it dropwise into the calcium chloride solution prepared by calcium chloride and the remaining deionized water, stir for 25~35 min, filter, wash with deionized water, freeze dry to obtain microspheres; (4) Mix the microspheres with potassium humate, the remaining betaine, neutral silicon and the remaining sodium alginate, and stir evenly to obtain a growth promoter and stress-resistant agent containing polyaspartic acid polypeptide.

[0026] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention is prepared by using deionized water, modified polyaspartic acid, compound functional bacterial agent, potassium humate, betaine, neutral silicon, sodium alginate and calcium chloride as raw materials. The microbial agent in the growth promoter and stress resistant agent is more stable in storage, and the growth promoter and stress resistant agent has a slow release effect that can promote plant growth for a long time.

[0027] (2) The modified polyaspartic acid of the present invention carries both anionic carboxyl groups and cationic amino groups as amphoteric polyelectrolytes. The cationic amino group of ε-polylysine can be stably combined with the anionic phospholipid bilayer and peptidoglycan layer on the surface of the functional bacterial cell membrane through electrostatic adsorption, forming a stable "polymer-bacterial body" combination before spray drying, thus avoiding the separation of the bacterial body and the carrier during atomization and drying.

[0028] (3) The modified polyaspartic acid of the present invention has excellent ion chelating ability and pH buffering ability, and can rapidly chelate Na in soil in saline-alkali environment. + CO3 2- HCO3 - The presence of salt and alkali ions creates a buffer microenvironment within the microspheres that isolates the bacteria from extreme external stresses. In arid environments, the hydrophilic groups of modified polyaspartic acid can lock in a large amount of water, preventing protein denaturation, nucleic acid damage, and cell membrane rupture caused by cell dehydration, thus fundamentally solving the problem of rapid bacterial inactivation under adverse conditions. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0030] Unless otherwise specified, those skilled in the art may select from the following post-processing operations, such as "mixing", "dispersion", "sedimentation", "centrifugation", "filtration", "granulation", "ultrasound", and "washing", based on actual conditions, without further limitation.

[0031] In the following preparation examples, embodiments, and comparative examples, Bacillus subtilis is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC 1.108; Bacillus megaterium is deposited at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC 1.6721; Bacillus mucilaginosus is deposited at the China Agricultural Microbiological Culture Collection Center (ACCC 19749); and Nostoc commune is deposited at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC NO: M2023322.

[0032] The specific method for preparing Bacillus subtilis bacterial suspension is described in paragraphs

[0033] to

[0038] of the specification of patent number CN111134142B, to make its OD 600 The value is 0.5.

[0033] For the specific method of preparing Bacillus megaterium culture, please refer to paragraph

[0051] of the specification of patent number CN108865943B, to make its OD 600 The value is 0.4.

[0034] For the specific method of preparing Bacillus mucilaginosus bacterial solution, please refer to paragraph

[0030] of the specification of patent number CN109970381B, to make its OD 600 The value is 0.6.

[0035] The specific method for preparing Nostoc commune solution is described in paragraphs

[0025] to

[0026] of the specification of patent number CN107603988B, which allows its OD... 600 The value is 0.5.

[0036] Preparation Example 1 The preparation method of modified polyaspartic acid includes the following steps: S1. Add 10g of polyaspartic acid (number average molecular weight of 20kDa) to 500ml of phosphate buffer (pH=5.0), then add 17g of EDC and 36g of NHS to make a mixed solution. S2. Add 6g of ε-polylysine to the mixed solution obtained in step S1 and mix. Adjust the pH of the system to 7.2 with 0.1M sodium hydroxide solution. Stir at room temperature in the dark for 12h. After the reaction is completed, dialyze the reaction solution through a dialysis bag for 72h and freeze-dry to obtain modified polyaspartic acid.

[0037] Preparation Example 2 The preparation method of modified polyaspartic acid is the same as that in Preparation Example 1, except that the number-average molecular weight of polyaspartic acid is 10 kDa.

[0038] Preparation Example 3 The preparation method of modified polyaspartic acid is the same as that in Preparation Example 1, except that the amount of ε-polylysine is 10g.

[0039] Preparation Example 4 The preparation method of modified polyaspartic acid is the same as that in Preparation Example 1, except that the amount of ε-polylysine is 2g.

[0040] Example 1 A plant growth promoter and stress-resistant agent containing polyaspartic peptides, wherein the raw materials of the plant growth promoter and stress-resistant agent, by weight, include the following raw materials: 500 parts deionized water, 60 parts modified polyaspartic acid, 15 parts compound functional bacterial agent, 15 parts potassium humate, 6 parts betaine, 4 parts neutral silicon, 1 part sodium alginate, and 3 parts calcium chloride.

[0041] The modified polyaspartic acid was prepared in Preparation Example 1; the composite functional microbial agent included Bacillus subtilis culture, Bacillus megaterium culture, Bacillus mucilaginosus culture and Nostoc commune culture in a volume ratio of 1:5:5:7.

[0042] A method for preparing a growth-promoting and stress-resistant agent containing polyaspartic peptides includes the following steps: (1) Mix modified polyaspartic acid with 77% by weight of deionized water, and add 80% by weight of sodium alginate to obtain mixture A; (2) Mix the compound functional microbial agent with 50% by weight of betaine to obtain mixture B; (3) Mix the mixture A obtained in step (1) with the mixture B obtained in step (2), add it dropwise into the calcium chloride solution prepared by calcium chloride and the remaining deionized water, stir for 30 min, filter, wash with deionized water, freeze dry, and obtain microspheres; (4) Mix the microspheres with potassium humate, the remaining betaine, neutral silicon and the remaining sodium alginate, and stir evenly to obtain a growth promoter and stress-resistant agent containing polyaspartic acid polypeptide.

[0043] Example 2 A plant growth promoter and stress-resistant agent containing polyaspartic peptides, wherein the raw materials of the plant growth promoter and stress-resistant agent, by weight, include the following raw materials: 450 parts deionized water, 50 parts modified polyaspartic acid, 10 parts compound functional bacterial agent, 10 parts potassium humate, 4 parts betaine, 2 parts neutral silicon, 0.5 parts sodium alginate, and 2 parts calcium chloride.

[0044] The modified polyaspartic acid was prepared in Preparation Example 1; the composite functional bacterial agent included Bacillus subtilis bacterial solution, Bacillus megaterium bacterial solution, Bacillus mucilaginosus bacterial solution and Nostoc commune algae solution in a volume ratio of 1:4:4:6.

[0045] A method for preparing a growth-promoting and stress-resistant agent containing polyaspartic peptides includes the following steps: (1) Mix modified polyaspartic acid with deionized water and add 75% sodium alginate by mass to obtain mixture A; (2) Mix the compound functional microbial agent with 45% by weight of betaine to obtain mixture B; (3) Mix the mixture A obtained in step (1) with the mixture B obtained in step (2), add it dropwise into the calcium chloride solution prepared by calcium chloride and the remaining deionized water, stir for 25 min, filter, wash with deionized water, freeze dry, and obtain microspheres; (4) Mix the microspheres with potassium humate, the remaining betaine, neutral silicon and the remaining sodium alginate, and stir evenly to obtain a growth promoter and stress-resistant agent containing polyaspartic acid polypeptide.

[0046] Example 3 A plant growth promoter and stress-resistant agent containing polyaspartic peptides, wherein the raw materials of the plant growth promoter and stress-resistant agent, by weight, include the following raw materials: 550 parts deionized water, 70 parts modified polyaspartic acid, 20 parts compound functional bacterial agent, 20 parts potassium humate, 8 parts betaine, 6 parts neutral silicon, 1.5 parts sodium alginate, and 4 parts calcium chloride.

[0047] The modified polyaspartic acid was prepared in Preparation Example 1; the composite functional microbial agent included Bacillus subtilis culture, Bacillus megaterium culture, Bacillus mucilaginosus culture and Nostoc commune culture in a volume ratio of 1:6:6:8.

[0048] A method for preparing a growth-promoting and stress-resistant agent containing polyaspartic peptides includes the following steps: (1) Mix modified polyaspartic acid with deionized water and add 85% sodium alginate by weight to obtain mixture A; (2) Mix the compound functional microbial agent with 55% by weight of betaine to obtain mixture B; (3) Mix the mixture A obtained in step (1) with the mixture B obtained in step (2), add it dropwise into the calcium chloride solution prepared by calcium chloride and the remaining deionized water, stir for 35 min, filter, wash with deionized water, freeze dry, and obtain microspheres; (4) Mix the microspheres with potassium humate, the remaining betaine, neutral silicon and the remaining sodium alginate, and stir evenly to obtain a growth promoter and stress-resistant agent containing polyaspartic acid polypeptide.

[0049] Example 4 A growth-promoting and stress-resistant agent containing polyaspartic acid polypeptide and its preparation method are described. The specific implementation method is the same as in Example 1, except that the modified polyaspartic acid is prepared by Example 2.

[0050] Example 5 A growth-promoting and stress-resistant agent containing polyaspartic acid polypeptide and its preparation method are described. The specific implementation method is the same as in Example 1, except that the modified polyaspartic acid is prepared by Example 3.

[0051] Example 6 A growth-promoting and stress-resistant agent containing polyaspartic acid polypeptide and its preparation method are described. The specific implementation method is the same as in Example 1, except that the modified polyaspartic acid is prepared by Example 4.

[0052] Example 7 A growth-promoting and stress-resistant agent containing polyaspartic acid polypeptide and its preparation method are described. The specific implementation method is the same as in Example 1, except that Bacillus subtilis bacterial solution is not added.

[0053] Example 8 A growth-promoting and stress-resistant agent containing polyaspartic acid polypeptide and its preparation method are described. The specific implementation method is the same as in Example 1, except that Nostoc commune liquid is not added.

[0054] Comparative Example 1 A growth-promoting and stress-resistant agent containing polyaspartic peptide and its preparation method are disclosed. The specific implementation method is the same as in Example 1, except that polyaspartic acid is used instead of modified polyaspartic acid.

[0055] Performance testing: 1. Test crops and scenarios: The test crops included conventional planting scenarios (pH=6.5, moisture content 75%), saline-alkali land scenarios (soil salinity 0.3%, pH=8.3), and drought stress scenarios (drought treatment involved stopping irrigation for 15 days during the jointing stage). The test crop was wheat (variety: Jimai 22).

[0056] 2. Test Grouping Each group had 3 replicates, with a plot area of ​​10m². Except for the treatment factor, other field management practices (fertilization and weeding) were kept consistent. The growth-promoting and stress-resistant agents of each embodiment and comparative example were diluted 1000 times with deionized water and sprayed on wheat at a rate of per 10m². 2 Use 0.5 kg of growth-promoting and stress-resistant agent diluted solution, and spray the blank group with water.

[0057] 3. Test Indicators (1) Growth promotion index: According to GB / T 3543.4-1995 Crop Seed Inspection Procedures Germination test, the number of germinated plants was counted on the 10th day after sowing, and the germination rate (%) was calculated; the plant height was uniformly measured before harvest at maturity to obtain the final plant height (cm); according to GB / T 3543.6-1995 Seed purity analysis (drying method), the whole plant was harvested at the crop maturity stage, blanched at 105℃, dried at 65℃ to constant weight, and the biomass of a single plant (g) was weighed; according to NY / T 1300-2007 Crop Field Yield Measurement Technical Specifications, the actual yield (kg / mu) was measured at the full maturity stage of the crop. (2) Stress resistance index: Yield reduction (%) under drought / salt-alkali stress. According to NY / T 1300-2007 Technical Specification for Field Yield Measurement of Crops, the yield was calculated at full maturity of the crop under stress treatment throughout the entire growth period. Yield reduction = (Yield of normal group) (Yield of the stressed group) ÷ Yield of the normal group × 100%; Pest and disease incidence (%) is determined according to the general rules of NY / T 1464.1-2021 Field Efficacy Test Guidelines for Pesticides (I), and is investigated during the peak period of pest and disease occurrence, and statistics are completed before harvest.

[0058] The test results are shown in Table 1, which shows the wheat planting situation.

[0059] Table 1

[0060] According to the data in Table 1, the growth-promoting and stress-resistant agents prepared in Examples 1-3 have good growth-promoting and stress-resistant effects. In Example 4, the change in the number-average molecular weight of polyaspartic acid resulted in defects in the microsphere shell, preventing the formation of a continuous and dense shell, leading to exposure of microorganisms and low survival rates in saline-alkali environments, thus weakening the growth-promoting and stress-resistant effects in saline-alkali environments. In Example 5, the change in the mass ratio of polyaspartic acid and ε-polylysine also led to excessive intermolecular cross-linking, threatening the survival environment of microorganisms. Low survival rate of microorganisms leads to poorer growth-promoting and stress-resistance effects; Example 6, due to the change in the mass ratio of polyaspartic acid and ε-polylysine, resulted in a decrease in encapsulation rate and a poorer growth-promoting and stress-resistance effect; Example 7, due to the absence of Bacillus subtilis culture, resulted in a poorer growth-promoting and stress-resistance effect, with a more significant decrease in salt and alkali tolerance and drought resistance; Example 8, due to the absence of Nostoc commune culture, resulted in a poorer growth-promoting and stress-resistance effect; Comparative Example 1, due to the use of polyaspartic acid instead of modified polyaspartic acid, resulted in a decrease in microbial encapsulation rate and a poorer growth-promoting and stress-resistance effect.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A growth-promoting and stress-resistant agent containing polyaspartic peptides, characterized in that, The plant growth-promoting and stress-resistant agent comprises, by weight, the following raw materials: 450-550 parts deionized water, 50-70 parts modified polyaspartic acid, 10-20 parts compound functional microbial agent, 10-20 parts potassium humate, 4-8 parts betaine, 2-6 parts neutral silicon, 0.5-1.5 parts sodium alginate, and 2-4 parts calcium chloride.

2. The growth-promoting and stress-resistant agent containing polyaspartic peptide according to claim 1, characterized in that, The modified polyaspartic acid is obtained by covalently grafting ε-polylysine amidation into the polyaspartic acid structure.

3. The growth-promoting and stress-resistant agent containing polyaspartic peptide according to claim 2, characterized in that, The method for preparing the modified polyaspartic acid includes the following steps: S1. Add polyaspartic acid to phosphate buffer, then add EDC and NHS to make a mixed solution; S2. Add ε-polylysine to the mixed solution obtained in step S1 and mix. Adjust the pH of the system to 7.2-7.4 and stir at room temperature in the dark for 10-14 hours. After the reaction is completed, dialyze the reaction solution through a dialysis bag for 70-74 hours and freeze-dry to obtain modified polyaspartic acid.

4. The growth-promoting and stress-resistant agent containing polyaspartic peptide according to claim 3, characterized in that, The mass ratio of polyaspartic acid to ε-polylysine is 1:(0.4~0.8).

5. The growth-promoting and stress-resistant agent containing polyaspartic peptide according to claim 3, characterized in that, The number-average molecular weight of the polyaspartic acid is 15-25 kDa.

6. The growth-promoting and stress-resistant agent containing polyaspartic peptide according to claim 3, characterized in that, The pH of the phosphate buffer solution is 7-8.

7. The growth-promoting and stress-resistant agent containing polyaspartic peptide according to claim 3, characterized in that, The mass ratio of EDC and NHS in step S2 to polyaspartic acid in step S1 is (1.5~2):(0.4~0.8):

1.

8. The growth-promoting and stress-resistant agent containing polyaspartic peptide according to claim 1, characterized in that, The compound functional microbial agent includes Bacillus subtilis bacterial solution, Bacillus megaterium bacterial solution, Bacillus mucilaginosus bacterial solution, and Nostoc commune algae solution.

9. The growth-promoting and stress-resistant agent containing polyaspartic peptide according to claim 8, characterized in that, The volume ratio of the Bacillus subtilis bacterial solution, Bacillus megaterium bacterial solution, Bacillus mucilaginosus bacterial solution, and Nostoc commune bacterial solution is 1:(0.4~0.6):(0.4~0.6):(0.6~0.8); the OD of the Bacillus subtilis bacterial solution is... 600 The OD value of Bacillus megaterium culture was 0.3~0.

8. 600 The OD value of Bacillus mucilaginosus bacterial culture is 0.2~0.

6. 600 The OD value of the Nostoc commune solution was 0.4~0.

8. 600 The value is 0.3~0.

7.

10. A method for preparing a growth-promoting and stress-resistant agent containing polyaspartic peptides as described in any one of claims 1 to 9, characterized in that, Includes the following steps: (1) Mix modified polyaspartic acid with 75-80% by weight of deionized water, and add 75-85% by weight of sodium alginate to obtain mixture A; (2) Mix the compound functional microbial agent with 45-55% by weight of betaine to obtain mixture B; (3) Mix the mixture A obtained in step (1) with the mixture B obtained in step (2), add it dropwise into the calcium chloride solution prepared by calcium chloride and the remaining deionized water, stir for 25~35 min, filter, wash with deionized water, freeze dry to obtain microspheres; (4) Mix the microspheres with potassium humate, the remaining betaine, neutral silicon and the remaining sodium alginate, and stir evenly to obtain a growth promoter and stress-resistant agent containing polyaspartic acid polypeptide.

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