Growth regulator for promoting colonization of plant rhizosphere microorganisms and application of growth regulator to crops

Abstract

The invention discloses a growth regulator for promoting colonization of plant rhizosphere microorganisms and application of the growth regulator to crops, a preparation method of the growth regulator comprises the following steps: S1, dropwise adding an aqueous solution of modified chitosan and a compound bacteria solution into a saturated boric acid solution of 1-2% calcium chloride, crosslinking and curing for 3-4 hours, washing with sterile water for 3-5 times, and drying to obtain the growth regulator for promoting colonization of the plant rhizosphere microorganisms; immobilized microorganisms are obtained; s2, sequentially adding nanocellulose crystals, sodium polyaspartate and organic fertilizer into the enteromorpha extracting solution, uniformly stirring and mixing, adding immobilized microorganisms, uniformly mixing, granulating, coating with modified chitosan, and drying to obtain the growth regulator. Through step-by-step design of microorganism immobilization, nutrition compounding and chitosan coating, function integration of microorganism protection, nutrition release and environmental response is achieved, the colonization efficiency of rhizosphere microorganisms is remarkably improved, the soil microenvironment is improved, and finally comprehensive improvement of plant growth and stress resistance is achieved; and the method has relatively high social use value and application prospect.

Description

Technical Field

[0001] The present invention relates to the field of planting technology, and in particular to a growth regulator for promoting the colonization of rhizosphere microorganisms of plants and its application in crops. Background Art

[0003] The root microbiome is regarded as the second genome of plants, and the plant-root-microorganism interaction is crucial for crop production; promoting plant growth through the root microbiome is an important supplement to the traditional germplasm resource breeding approach. The main ways for microorganisms and plants to interact and cooperate in stress resistance are as follows: First, microorganisms help plants adapt to stress by regulating the utilization of soil nutrients and physiological metabolic activities of plants. Second, stress changes the components of root exudates to construct a stress-resistant root microbiome community to achieve mutual regulation.

[0004] As an important agricultural region in China, the ecological vulnerability and the wide distribution of medium and low-yield farmland in the Loess Plateau are particularly prominent. The main limiting factors in this region are low soil fertility and frequent and variable drought-prone climate. Therefore, crops in this region have been in a complex adversity of water and fertilizer deficiency for a long time. Developing targeted products for stress resistance and growth promotion of crops in this region is of great significance for ensuring food security. In traditional agricultural management, the method of increasing yields through chemical fertilizers and pesticides has been difficult to meet the needs of sustainable development and may exacerbate soil degradation. In recent years, rhizosphere microorganisms, as important regulatory factors for plant stress resistance, the plant-microorganism cooperative stress resistance mechanism mediated by them has become a research hotspot. However, the existing technologies still have deficiencies in the following aspects: The cooperative stress resistance mechanism between microorganisms and crops is unclear: For complex adversities such as water and fertilizer deficiency, the molecular mechanism by which crop root exudates regulate the microbial community structure, function and colonization efficiency has not been clarified, resulting in unstable field application effects of growth regulators.

[0005] Chinese Patent CN114080875A discloses a method for improving and repairing sandy grassland soil. By sequentially arranging a support layer, a first nutrient layer and a second nutrient layer, the isolation and support of the original sandy soil are achieved. The second nutrient layer is composed of imported soil, original sandy soil and a modifier. The modifier is prepared according to the following mass ratio: 200-300 parts of poplar wood cellulose slow-release substance, 40-50 parts of polyacrylamide, 100-200 parts of peat, 50-60 parts of calcium oxide, 30-40 parts of biochar, 10-20 parts of chitosan, 50-60 parts of urea, 50-60 parts of superphosphate, 40-50 parts of highland barley bran, 100-150 parts of cattle and sheep manure and 10-20 parts of microbial inoculum. However, the microbial inoculum in the modifier is not activated and is directly mixed with imported soil and sandy soil, and its microbial colonization ability and adaptability are not clear, and it is uncertain whether the expected goal can be achieved.

[0006] In existing soil conditioners, straw, peat, weathered coal, animal manure, etc. are often mixed and added as conditioner aggregates to provide certain nutrients for the soil. Usually, it is a simple mixing and stirring without harmless or activation treatment, resulting in low activity of functional flora. Therefore, the active nutrients in the conditioner are few, and the microbial diversity is low, which is not conducive to the rapid growth of plants in drought stress. Moreover, during the slow decomposition process of the conditioner, substances harmful to plants may also be produced, affecting the conditioning effect.

[0007] For the above reasons, there is an urgent need to develop a growth regulator that can effectively inhibit diseases and promote the colonization of rhizosphere microorganisms of plants, thereby improving the utilization rate of soil resources. Summary of the Invention

[0008] To solve the problems mentioned in the above background art, the present invention provides a growth regulator for promoting the colonization of rhizosphere microorganisms of plants and its application in crops.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A growth regulator for promoting the colonization of rhizosphere microorganisms of plants, and the preparation method of the growth regulator includes the following steps:

[0011] S1. Drop the aqueous solution of modified chitosan and the compound bacterial solution into a saturated boric acid solution of 1-2% calcium chloride, crosslink and solidify for 3-4 h, and wash with sterile water 3-5 times to obtain immobilized microorganisms;

[0012] S2. Sequentially add nanocrystalline cellulose, sodium polyaspartate, and organic fertilizer to the Enteromorpha extract, stir and mix evenly, then add the immobilized microorganisms, mix and granulate, and coat and dry with modified chitosan to obtain the growth regulator.

[0013] Preferably, the crosslinking and solidifying temperature is 20-30 °C; the stirring rate in step S2 is 200- 500 rpm, and the stirring time is 10-15 minutes; dry at 30-35 °C for 6-8 hours.

[0014] Preferably, the preparation method of modified chitosan includes the following steps:

[0015] Raw material treatment: Dissolve chitosan (deacetylation degree ≥ 85%) in 2% acetic acid aqueous solution to prepare a solution with a concentration of 4-6%, and stir at 60-65 °C for 2-3 h until completely dissolved;

[0016] Crosslinking and activation: Add N,N'-carbonyldiimidazole (CDI, molar ratio 1.2 times that of chitosan amino group), react at room temperature for 2-3 h, and activate the amino group to generate an imidazole carbamate intermediate;

[0017] Functional grafting: Gradually add dodecyl glycidyl ether containing hydrophobic groups drop by drop, with a molar ratio of 1:0.8, heat up to 55 °C, and react for 10 h to form chitosan grafted with alkyl chains (degree of substitution 18 - 22%);

[0018] Purification: Dialyze (MWCO 8 kDa) for 60 - 72 h and freeze-dry to obtain modified chitosan.

[0019] Preferably, the mass fraction of the composite bacterial solution is 25 - 30%; the composite bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of (4 - 7):(11 - 15):(3 - 8).

[0020] Preferably, the preparation method of the Enteromorpha extract includes the following steps: Add Enteromorpha powder to sterile deionized water to obtain an Enteromorpha powder suspension, boil the above Enteromorpha powder suspension for 30 - 40 min, adjust the pH value to 7.0 - 7.5 after cooling to room temperature, and prepare the Enteromorpha extract.

[0021] Wherein the particle size of the Enteromorpha powder is 40 - 80 mesh and the purity is greater than 99%.

[0022] Preferably, the organic fertilizer is one or a mixture of bone meal, raw skin powder, rapeseed powder, soybean powder, and fish meal.

[0023] Preferably, in step S2, the addition amount of the nanocrystalline cellulose is 2 - 4 g / L; the addition amount of sodium polyaspartate is 2 - 5 g / L; the addition amount of the organic fertilizer is 26 - 30 g / L; the addition amount of the immobilized microorganism is 25 - 30 g / L.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. In the present invention, the amino group of chitosan is activated by N,N'-carbonyldiimidazole (CDI) and grafted with dodecyl hydrophobic groups, significantly enhancing the hydrophobicity and mechanical strength of chitosan. The introduction of hydrophobic chains forms a barrier structure, reducing the damage of the external environment, such as moisture and ultraviolet rays, to the immobilized microorganisms, and at the same time improving the adhesion ability of the carrier in the rhizosphere. The particles coated with modified chitosan slowly degrade in the rhizosphere soil, continuously releasing microorganisms and nutrients, and prolonging the microbial colonization cycle.

[0026] 2. In the present invention, the calcium chloride - boric acid system forms a three-dimensional cross-linked network, fixing composite bacterial groups such as EM bacteria, Bacillus thuringiensis, and Bacillus subtilis in the chitosan matrix, avoiding the inactivation of the bacterial cells during the preparation process. Among them, EM bacteria promote the decomposition of organic matter, Bacillus thuringiensis inhibits soil-borne pathogenic bacteria, and Bacillus subtilis secretes growth-promoting substances, and the three work together to enhance the rhizosphere microecological balance.

[0027] 3. In the present invention, Enteromorpha prolifera releases polysaccharides, amino acids and trace elements after boiling extraction, directly stimulates the development of plant roots, and provides a carbon source for microorganisms to promote their metabolic activity. Bone meal, rapeseed meal, etc. are rich in nitrogen, phosphorus, potassium and organic matter. Combined with the synergistic effect of sodium polyaspartate, the nutrient utilization rate is improved and the risk of soil compaction is reduced.

[0028] 4. Through the step-by-step design of immobilizing microorganisms → nutrient compounding → chitosan coating, the present invention realizes the functional integration of microorganism protection, nutrient release and environmental response, significantly improves the colonization efficiency of rhizosphere microorganisms, improves the soil microenvironment, and finally comprehensively improves the plant growth and stress resistance ability, with high social use value and application prospects. Specific Embodiments

[0029] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0030] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0031] Nanocrystalline cellulose was purchased from Nanjing Tianlu Nano Technology Co., Ltd., model: CNF-C;

[0032] Sodium polyaspartate was purchased from Hebei Anno Environmental Protection Technology Co., Ltd., model: PASP;

[0033] Chitosan was purchased from Shanghai Chuangsai Technology Co., Ltd., model: PN02008 (Bofeimeike brand, BR grade, 90% purity);

[0034] N,N'-carbonyldiimidazole was purchased from Shanghai Xiangu Chemical Co., Ltd., CAS number: 530-62-1;

[0035] The selected EM bacteria were purchased from Chaoyang Huaxing Bioengineering Co., Ltd.; Bacillus thuringiensis was purchased from Shanghai Enzyme Research Biotechnology Co., Ltd., model: TO8018; Bacillus subtilis was purchased from Hebei Feiyuan Agricultural Water Soluble Fertilizer Factory.

[0036] Preparation Example 1

[0037] The preparation method of modified chitosan includes the following steps:

[0038] Dissolve 10 g of chitosan in 240 mL of 1% acetic acid aqueous solution to prepare a 4% concentration solution, and stir at 60 °C for 2 h until completely dissolved;

[0039] Add 8 g of N,N'-carbonyldiimidazole and react at room temperature for 3 h to activate the amino group to generate an imidazole carbamate intermediate;

[0040] Dropwise add 5 g of dodecyl glycidyl ether containing a hydrophobic group, raise the temperature to 55 °C, and react for 10 h to form an alkyl-chain grafted chitosan; dialyze for 72 h and freeze-dry to obtain the modified chitosan.

[0041] Preparation Example 2

[0042] The preparation method of the modified chitosan includes the following steps:

[0043] Dissolve 10 g of chitosan in 190 mL of 2% acetic acid aqueous solution to prepare a 5% concentration solution, and stir at 65 °C for 2 h until completely dissolved;

[0044] Add 8 g of N,N'-carbonyldiimidazole and react at room temperature for 2.5 h to activate the amino group to generate an imidazole carbamate intermediate;

[0045] Dropwise add 5 g of dodecyl glycidyl ether containing a hydrophobic group, raise the temperature to 55 °C, and react for 10 h to form an alkyl-chain grafted chitosan; dialyze for 68 h and freeze-dry to obtain the modified chitosan.

[0046] Preparation Example 3

[0047] The preparation method of the modified chitosan includes the following steps:

[0048] Dissolve 10 g of chitosan in 157 mL of 2% acetic acid aqueous solution to prepare a 6% concentration solution, and stir at 65 °C for 3 h until completely dissolved;

[0049] Add 8 g of N,N'-carbonyldiimidazole and react at room temperature for 3 h to activate the amino group to generate an imidazole carbamate intermediate;

[0050] Dropwise add 5 g of dodecyl glycidyl ether containing a hydrophobic group, raise the temperature to 55 °C, and react for 10 h to form an alkyl-chain grafted chitosan; dialyze for 72 h and freeze-dry to obtain the modified chitosan.

[0051] Preparation Example 4

[0052] The preparation method of the Enteromorpha extract includes the following steps:

[0053] Add 250 g of Enteromorpha powder to 1 L of sterile deionized water to obtain an Enteromorpha powder suspension, boil the above Enteromorpha powder suspension for 30 min, and adjust the pH value to 7.0 after cooling to room temperature to prepare the Enteromorpha extract.

[0054] Among them, the particle size of the Enteromorpha powder is 50 mesh and the purity is 99.2%.

[0055] Example 1

[0056] A growth regulator for promoting the colonization of plant rhizosphere microorganisms, and the preparation method of the growth regulator comprises the following steps:

[0057] S1. Drop 25 mL of the aqueous solution of the modified chitosan prepared in Preparation Example 1 and 15 mL of the compound bacterial solution into 100 mL of a saturated boric acid solution of 1% calcium chloride, crosslink and solidify at 20 °C for 3 h, and wash 3 times with sterile water to obtain immobilized microorganisms; wherein the mass fraction of the aqueous solution of the modified chitosan is 75%;

[0058] S2. Sequentially add 2 g of nanocrystalline cellulose, 2 g of sodium polyaspartate, and 26 g of bone meal to 1 L of the Enteromorpha prolifera extract prepared in Preparation Example 4, stir at a stirring rate of 200 rpm for 10 minutes for mixing, then add 25 g of the immobilized microorganisms, mix and granulate, coat with modified chitosan, and dry at 30 °C for 6 hours to obtain the growth regulator.

[0059] The mass fraction of the compound bacterial solution is 25%; the compound bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of 4:11:3.

[0060] Example 2

[0061] A growth regulator for promoting the colonization of plant rhizosphere microorganisms, and the preparation method of the growth regulator comprises the following steps:

[0062] S1. Drop 25 mL of the aqueous solution of the modified chitosan prepared in Preparation Example 1 and 15 mL of the compound bacterial solution into 100 mL of a saturated boric acid solution of 1% calcium chloride, crosslink and solidify at 25 °C for 3.5 h, and wash 4 times with sterile water to obtain immobilized microorganisms; wherein the mass fraction of the aqueous solution of the modified chitosan is 78%;

[0063] S2. Sequentially add 3 g of nanocrystalline cellulose, 4 g of sodium polyaspartate, and 28 g of raw skin powder to 1 L of the Enteromorpha prolifera extract prepared in Preparation Example 4, stir at a stirring rate of 350 rpm for 12 minutes for mixing, then add 29 g of the immobilized microorganisms, mix and granulate, coat with modified chitosan, and dry at 32 °C for 7 hours to obtain the growth regulator.

[0064] The mass fraction of the compound bacterial solution is 28%; the compound bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of 5:12:6.

[0065] Example 3

[0066] A growth regulator for promoting the colonization of plant rhizosphere microorganisms, and the preparation method of the growth regulator comprises the following steps:

[0067] S1. Add 25 mL of the aqueous solution of the modified chitosan prepared in Preparation Example 1 and 15 mL of the compound bacterial solution dropwise into 100 mL of a saturated boric acid solution of 1% calcium chloride, crosslink and cure at 30 °C for 4 h, and wash 5 times with sterile water to obtain the immobilized microorganism; wherein the mass fraction of the aqueous solution of the modified chitosan is 80%;

[0068] S2. Add 4 g of nanocrystalline cellulose, 5 g of sodium polyaspartate, and 30 g of fish meal to 1 L of the Enteromorpha prolifera extract prepared in Preparation Example 4 in sequence. The stirring rate is 500 rpm, and the stirring time is 15 minutes. After mixing evenly, add 29 g of the immobilized microorganism, mix evenly and granulate, coat with modified chitosan, and dry at 35 °C for 8 h to obtain the growth regulator.

[0069] The mass fraction of the compound bacterial solution is 30%; the compound bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of 7:15:8.

[0070] Example 4

[0071] A growth regulator for promoting the colonization of plant rhizosphere microorganisms, and the preparation method of the growth regulator includes the following steps:

[0072] S1. Add 25 mL of the aqueous solution of the modified chitosan prepared in Preparation Example 2 and 15 mL of the compound bacterial solution dropwise into 100 mL of a saturated boric acid solution of 1% calcium chloride, crosslink and cure at 20 °C for 3 h, and wash 3 times with sterile water to obtain the immobilized microorganism; wherein the mass fraction of the aqueous solution of the modified chitosan is 75%;

[0073] S2. Add 2 g of nanocrystalline cellulose, 2 g of sodium polyaspartate, and 26 g of bone meal to 1 L of the Enteromorpha prolifera extract prepared in Preparation Example 4 in sequence. The stirring rate is 200 rpm, and the stirring time is 10 minutes. After mixing evenly, add 25 g of the immobilized microorganism, mix evenly and granulate, coat with modified chitosan, and dry at 30 °C for 6 h to obtain the growth regulator.

[0074] The mass fraction of the compound bacterial solution is 25%; the compound bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of 4:11:3.

[0075] Example 5

[0076] A growth regulator for promoting the colonization of plant rhizosphere microorganisms, and the preparation method of the growth regulator includes the following steps:

[0077] S1. Add 25 mL of the aqueous solution of the modified chitosan prepared in Preparation Example 3 and 15 mL of the composite bacterial solution dropwise into 100 mL of a saturated boric acid solution of 1% calcium chloride, crosslink and cure at 20 °C for 3 h, and wash 3 times with sterile water to obtain the immobilized microorganism; wherein the mass fraction of the aqueous solution of the modified chitosan is 75%;

[0078] S2. Add 2 g of nanocrystalline cellulose, 2 g of sodium polyaspartate, and 26 g of bone meal to 1 L of the Enteromorpha prolifera extract prepared in Preparation Example 4 in sequence. Stir at a stirring rate of 200 rpm for 10 minutes. After mixing evenly, add 25 g of the immobilized microorganism, mix evenly and granulate, coat with modified chitosan, and dry at 30 °C for 6 hours to obtain the growth regulator.

[0079] The mass fraction of the composite bacterial solution is 25%; the composite bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of 4:11:3.

[0080] Example 6

[0081] A growth regulator for promoting the colonization of rhizosphere microorganisms of plants, and the preparation method of the growth regulator includes the following steps:

[0082] S1. Add 25 mL of the aqueous solution of the modified chitosan prepared in Preparation Example 2 and 15 mL of the composite bacterial solution dropwise into 100 mL of a saturated boric acid solution of 1% calcium chloride, crosslink and cure at 25 °C for 3.5 h, and wash 4 times with sterile water to obtain the immobilized microorganism; wherein the mass fraction of the aqueous solution of the modified chitosan is 78%;

[0083] S2. Add 3 g of nanocrystalline cellulose, 4 g of sodium polyaspartate, and 28 g of hide powder to 1 L of the Enteromorpha prolifera extract prepared in Preparation Example 4 in sequence. Stir at a stirring rate of 350 rpm for 12 minutes. After mixing evenly, add 29 g of the immobilized microorganism, mix evenly and granulate, coat with modified chitosan, and dry at 32 °C for 7 hours to obtain the growth regulator.

[0084] The mass fraction of the composite bacterial solution is 28%; the composite bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of 5:12:6.

[0085] Example 7

[0086] A growth regulator for promoting the colonization of rhizosphere microorganisms of plants, and the preparation method of the growth regulator includes the following steps:

[0087] S1. Add 25 mL of the aqueous solution of the modified chitosan prepared in Preparation Example 3 and 15 mL of the compound bacterial solution dropwise into 100 mL of a saturated boric acid solution of 1% calcium chloride, crosslink and cure at 25 °C for 3.5 h, and wash 4 times with sterile water to obtain immobilized microorganisms; wherein the mass fraction of the aqueous solution of the modified chitosan is 78%.

[0088] S2. Sequentially add 3 g of nanocrystalline cellulose, 4 g of sodium polyaspartate, and 28 g of raw hide powder to 1 L of the Enteromorpha prolifera extract prepared in Preparation Example 4, stir at a stirring rate of 350 rpm for 12 minutes until evenly mixed, then add 29 g of immobilized microorganisms, mix evenly, granulate, coat with modified chitosan, and dry at 32 °C for 7 hours to obtain a growth regulator.

[0089] The mass fraction of the compound bacterial solution is 28%; the compound bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of 5:12:6.

[0090] Example 8

[0091] A growth regulator for promoting the colonization of rhizosphere microorganisms in plants, and the preparation method of the growth regulator comprises the following steps:

[0092] S1. Add 25 mL of the aqueous solution of the modified chitosan prepared in Preparation Example 2 and 15 mL of the compound bacterial solution dropwise into 100 mL of a saturated boric acid solution of 1% calcium chloride, crosslink and cure at 30 °C for 4 h, and wash 5 times with sterile water to obtain immobilized microorganisms; wherein the mass fraction of the aqueous solution of the modified chitosan is 80%.

[0093] S2. Sequentially add 4 g of nanocrystalline cellulose, 5 g of sodium polyaspartate, and 30 g of fish meal to 1 L of the Enteromorpha prolifera extract prepared in Preparation Example 4, stir at a stirring rate of 500 rpm for 15 minutes until evenly mixed, then add 29 g of immobilized microorganisms, mix evenly, granulate, coat with modified chitosan, and dry at 35 °C for 8 hours to obtain a growth regulator.

[0094] The mass fraction of the compound bacterial solution is 30%; the compound bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of 7:15:8

[0095] Example 9

[0096] A growth regulator for promoting the colonization of rhizosphere microorganisms in plants, and the preparation method of the growth regulator comprises the following steps:

[0097] S1. Add 25 mL of the aqueous solution of the modified chitosan prepared in Preparation Example 3 and 15 mL of the composite bacterial solution dropwise into 100 mL of a saturated boric acid solution of 1% calcium chloride, crosslink and cure at 30 °C for 4 h, and wash 5 times with sterile water to obtain the immobilized microorganism; wherein the mass fraction of the aqueous solution of the modified chitosan is 80%;

[0098] S2. Sequentially add 4 g of nanocrystalline cellulose, 5 g of sodium polyaspartate, and 30 g of fish meal to 1 L of the Enteromorpha prolifera extract prepared in Preparation Example 4. The stirring rate is 500 rpm, and the stirring time is 15 minutes. After mixing evenly, add 29 g of the immobilized microorganism, mix well and granulate, coat with modified chitosan, and dry at 35 °C for 8 hours to obtain the growth regulator.

[0099] The mass fraction of the composite bacterial solution is 30%; the composite bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of 7:15:8.

[0100] Comparative Example 1

[0101] The difference between this comparative example and Example 1 is that the aqueous solution of the modified chitosan prepared in Preparation Example 1 is replaced with an aqueous solution of commercially available chitosan purchased from Hebei Lihua Biotechnology Co., Ltd.

[0102] Comparative Example 2

[0103] The difference between this comparative example and Example 1 is that the aqueous solution of the modified chitosan prepared in Preparation Example 1 is replaced with activated carbon purchased from Henan Songshan Science and Technology Co., Ltd., model SSCP-107.

[0104] Comparative Example 3

[0105] The difference between this comparative example and Example 1 is that no nanocrystalline cellulose is added.

[0106] This experimental example is a study on the effect of the growth regulators prepared in Examples 1-9 and Comparative Examples 1-3 on the germination of wheat seeds:

[0107] The wheat variety is Xiaoyan No. 2. Divide the wheat seeds into 5 portions, with 100 seeds in each portion. The first portion does not add a growth regulator, and the 2nd - 10th portions sequentially add the growth regulators of Examples 1-6 and Comparative Examples 1-3. Mix the seeds and the growth regulator according to a mass ratio of 10:1 for seed dressing, and then sow. The sowing and management methods are the same; calculate the germination potential and germination rate of the wheat seeds;

[0108] Germination potential (wheat) = Number of germinated seeds on the 3rd day / Total number of tested seeds * 100%;

[0109] Germination rate = Total number of germinated seeds / Total number of tested seeds * 100%;

[0110] The results are shown in Table 1 as follows:

[0111] Table 1

[0112]

[0113]

[0114] The growth regulator prepared by the present invention can promote the germination of seeds and has a better effect than the growth regulator of the comparative example.

[0115] Taking Xiaoyan No. 2 wheat as seeds, a seedling growth promotion experiment was carried out;

[0116] The wheat seeds were divided into 5 portions, with 200 seeds in each portion. The first portion was not added with a growth regulator, and the 2nd - 5th portions were successively added with the growth regulators of Example 3 and Comparative Examples 1 - 3. The seeds were dressed with the growth regulator according to the mass ratio of wheat seeds to the growth regulator of 10:1, and then sown. The sowing and management methods were the same;

[0117] After sowing for a period of time, 20 wheat seedlings were randomly selected from each portion of wheat seeds, and the plant height, root length, and fresh weight were measured. Then, the average values were calculated. The results are shown in Table 2 as follows:

[0118] Table 2

[0119] Test item Plant height (cm) Root length (cm) Fresh weight (g) Blank group 22.68 13.85 1.56 Example 1 38.89 17.85 3.25 Example 2 38.51 18.15 3.15 Example 3 39.12 18.25 3.11 Example 4 39.28 17.95 3.10 Example 5 38.91 17.78 3.08 Example 6 39.25 18.91 3.28 Example 7 39.58 18.65 3.25 Example 8 39.17 19.24 3.19 Example 9 38.88 19.08 3.21 Comparative example 1 26.98 13.58 2.12 Comparative example 2 28.91 13.98 2.05 Comparative example 3 30.15 15.88 2.58

[0120] It can be seen from Table 2 that in Examples 1 - 9, the plant height, root length, and fresh weight of plants have been greatly improved, indicating that the growth regulator in the present invention significantly enhances the rhizosphere microbial colonization ability and activity, increases soil nutrients, improves the plant habitat, and promotes plant growth and development.

[0121] The growth regulator prepared by the present invention can promote the growth and development of seedlings and promote the rhizosphere microbial colonization of plants, and the growth promotion effect is significantly improved compared with the growth regulator of the comparative example.

[0122] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A growth regulator for promoting the colonization of rhizosphere microorganisms in plants, and the preparation method of the growth regulator comprises the following steps: S1. Drop an aqueous solution of modified chitosan and a compound bacterial solution into a saturated boric acid solution of 1-2% calcium chloride, crosslink and cure for 3-4 h, and wash with sterile water for 3-5 times to obtain immobilized microorganisms; S2. Sequentially add nanocrystalline cellulose, sodium polyaspartate, and organic fertilizer to the Enteromorpha extract, stir and mix evenly, then add the immobilized microorganisms, mix evenly and granulate, and coat and dry with modified chitosan to obtain the growth regulator.

2. The growth regulator for promoting the colonization of plant rhizosphere microorganisms according to claim 1, wherein, The crosslinking and curing temperature is 20-30 °C; the stirring rate in step S2 is 200-500 rpm, and the stirring time is 10-15 minutes; dry at 30-35 °C for 6-8 hours.

3. A growth regulator for promoting the colonization of plant rhizosphere microorganisms according to claim 1, characterized in that, The preparation method of the modified chitosan comprises the following steps: Raw material treatment: Dissolve chitosan in a 2% aqueous acetic acid solution to prepare a solution with a concentration of 4-6%, and stir at 60-65 °C for 2-3 h until completely dissolved; Crosslinking and activation: Add N,N'-carbonyldiimidazole and react at room temperature for 2-3 h to activate the amino group to generate an imidazole carbamate intermediate; Functional grafting: Dropwise add dodecyl glycidyl ether containing a hydrophobic group, with a molar ratio of 1:0.8, heat up to 55 °C, and react for 10 h to form chitosan grafted with an alkyl chain; Purification: Dialyze for 60-72 h and freeze-dry to obtain modified chitosan.

4. The growth regulator for promoting the colonization of rhizosphere microorganisms of plants according to claim 1, characterized in that, The deacetylation degree of the chitosan is ≥85%.

5. A growth regulator for promoting the colonization of plant rhizosphere microorganisms according to claim 1, characterized in that, The substitution degree of the chitosan grafted with an alkyl chain is 18-22%.

6. The growth regulator for promoting the colonization of plant rhizosphere microorganisms according to claim 1, characterized in that, The mass fraction of the compound bacterial solution is 25-30%; the compound bacterial solution is prepared by compounding EM bacteria, Bacillus thuringiensis, and Bacillus subtilis according to a mass ratio of (4-7):(11-15):(3-8).

7. A growth regulator for promoting the colonization of plant rhizosphere microorganisms according to claim 1, characterized in that The preparation method of the Enteromorpha extract comprises the following steps: Add Enteromorpha powder to sterile deionized water to obtain an Enteromorpha powder suspension, boil the above Enteromorpha powder suspension for 30-40 min, cool to room temperature, and adjust the pH value to 7.0-7.5 to obtain the Enteromorpha extract.

8. A growth regulator for promoting the colonization of plant rhizosphere microorganisms according to claim 1, characterized in that, The organic fertilizer is one or a mixture of bone meal, raw skin powder, rapeseed powder, soybean powder, and fish meal.

9. A growth regulator for promoting the colonization of plant rhizosphere microorganisms according to claim 1, characterized in that In step S2, the addition amount of the nanocrystalline cellulose is 2-4 g / L; the addition amount of sodium polyaspartate is 2-5 g / L; the addition amount of the organic fertilizer is 26-30 g / L; the addition amount of the immobilized microorganisms is 25-30 g / L.

10. An application of the growth regulator for promoting the colonization of rhizosphere microorganisms in plants according to any one of claims 1-9 on crops, and the growth regulator is applied to crops on the Loess Plateau.

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