Preparation of combined water-soluble fertilizer containing citric acid with immune activation function and application thereof on tomatoes
Patent Information
- Application Number
- CN202511312708.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-15
- Publication Date
- 2026-10-20
AI Technical Summary
[0003]本发明的第一个目的是提供一种含柠檬苦酸具有免疫激活功能的组合水溶肥的制备方法以解决现有的化学农药不能调控植物内源防御信号的技术问题
[0016]本发明以柠檬苦酸为核心成分，通过调控番茄的苯丙烷代谢通路实现抗病增产，柠檬苦酸可通过激活L-苯丙氨酸解氨酶(PAL)的活性，促进酚类物质，香豆酸增强抗病性。
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of novel functional fertilizer technology, specifically relating to the preparation of a combination water-soluble fertilizer containing citric acid with immune-activating function and its application on tomatoes. Background Technology
[0002] Current tomato cultivation relies heavily on chemical pesticides and conventional water-soluble fertilizers, but long-term use can lead to increased pathogen resistance, decreased soil microbial diversity, and environmental pollution. For example, while synthetic chemical fertilizers can promote growth in the short term, they inhibit the activity of beneficial rhizosphere bacteria, disrupt the soil ecological balance, and exacerbate soil-borne diseases (such as bacterial wilt). Existing immune inducers (such as chitosan oligosaccharides and plant activators) can induce crop resistance, but they have short-lasting effects and require frequent application. Current technologies often manage disease resistance and fertilization separately, lacking an integrated approach that combines immune activation and nutrient supply. For instance, chemical pesticides only target disease control, while traditional water-soluble fertilizers focus on nutrient supply, failing to regulate endogenous plant defense signals. Summary of the Invention
[0003] The first objective of this invention is to provide a method for preparing a combined water-soluble fertilizer containing citric acid with immune-activating function to solve the technical problem that existing chemical pesticides cannot regulate endogenous defense signals in plants.
[0004] The second objective of this invention is to provide a combination water-soluble fertilizer containing citric acid with immune-activating function for use on tomatoes.
[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0006] A combination water-soluble fertilizer containing citric acid with immune-activating function comprises, by weight percentage: 0.25-0.3% citric acid nanoliposomes, 60-65% NPK coated with modified sodium alginate, 4-6% compound probiotic carrier, 0.8-1% trans-cinnamic acid derivative, 2-3% sodium lignosulfonate, and the balance being a chelate containing humic acid.
[0007] Furthermore, the particle size of the citric acid nanoliposomes is 80-120 nm; the preparation method of the citric acid nanoliposomes is as follows: soybean lecithin, cholesterol and DSPE-PEG2000 are mixed and dissolved in ethanol to obtain an oil phase, citric acid is dissolved in water to obtain an aqueous phase, the oil phase and the aqueous phase are mixed and the solvent is removed by rotary evaporation to obtain the final product.
[0008] Furthermore, the molar ratio of soybean lecithin, cholesterol, and DSPE-PEG2000 is 60:35:5, the concentration of the oil phase is 6 mg / mL, and the concentration of the aqueous phase is 0.4 mg / mL.
[0009] Furthermore, the preparation method of the modified sodium alginate-coated NPK is as follows: the modifier is mixed with sodium alginate solution, the pH is adjusted to neutral, and the reaction is carried out at 80°C for 2 hours. After centrifugation and drying, modified sodium alginate is obtained; NPK raw material is granulated to obtain NPK particles; modified sodium alginate is dissolved in solvent to obtain modified sodium alginate solution, the modified sodium alginate solution is sprayed onto the surface of NPK particles, and then calcium chloride solution is sprayed on for crosslinking, cured, and dried to obtain the final product.
[0010] Furthermore, the sodium alginate solution has a mass fraction of 2-5%, the modifier is chitosan or nano-clay, and the mass ratio of sodium alginate to the modifier is 100:10; the mass ratio of N, P, and K in the NPK raw material is 10:4:6; the mass fraction of the modified sodium alginate solution is 3-8%; the spraying temperature of the modified sodium alginate solution onto the surface of NPK particles is 40-60℃, and the spraying rate is 5-15 mL / min; the mass fraction of the calcium chloride solution is 2-6%, and the crosslinking time is 10-40 min.
[0011] Furthermore, the preparation method of the compound probiotic carrier is as follows: straw and livestock manure are crushed to 2-5cm to obtain raw materials, the carbon-nitrogen ratio is adjusted to 25-30:1, the water content is 60-65%, and then Penicillium spore suspension is inoculated for aerobic fermentation to obtain the first stage product; the first stage product is cooled to 40-45℃, the pH is adjusted to 6.5-7.5, and then Bacillus subtilis bacterial solution is inoculated, and facultative anaerobic fermentation is performed to obtain the final product.
[0012] Furthermore, the inoculum size of the Penicillium spore suspension is 10. 6 -10 7 The aerobic fermentation conditions are: temperature 25-30℃, pH 5.5-6.5, and time 7-10 days; the inoculum size of the Bacillus subtilis culture is 10 CFU / g. 8 -10 9 The facultative anaerobic fermentation is carried out at a temperature of 35-45℃ for 3-5 days, with a yield of CFU / g of raw material.
[0013] Furthermore, the preparation method of the chelate containing humic acid is as follows: using furfural residue, crop straw and farmyard manure as base materials, fermentation is carried out until the humic acid content is ≥70%, then alkaline solution is added, and after centrifugation, humic acid supernatant is obtained. The humic acid supernatant, EDTA-2Na and sodium hydroxide are mixed and stirred until completely dissolved, and then zinc ions, manganese ions, copper ions and ferrous ions are added in sequence. The pH is adjusted to 6.5, and after filtration, chelate containing humic acid is obtained.
[0014] A method for preparing a combination water-soluble fertilizer containing citric acid with immune-activating function includes the following steps: mixing the prescribed amount of citric acid nanoliposomes with NPK coated with modified sodium alginate and dissolving it in water; sequentially adding trans-cinnamic acid derivatives and a compound probiotic carrier; adding humic acid chelated liquid at 4-6℃; and adding sodium lignin sulfonate to adjust the pH to 7 to obtain the final product.
[0015] Application of a combination water-soluble fertilizer containing citric acid and possessing immune-activating function in regulating the phenylpropanone metabolic pathway in tomatoes. Beneficial effects of this invention:
[0016] This invention uses citric acid as the core component to achieve disease resistance and increased yield in tomatoes by regulating the phenylpropanoid metabolic pathway. Citric acid can enhance disease resistance by activating the activity of L-phenylalanine ammonia-lyase (PAL) and promoting the production of phenolic substances and coumaric acid.
[0017] This invention provides a water-soluble fertilizer containing citric acid and possessing immune-activating properties. It contains elements essential for tomato growth, meeting the nutrient needs of tomatoes at different growth stages and promoting plant growth and development. Citric acid activates the tomato's own immune system, enhancing its resistance to pests, diseases, and environmental stresses. This invention improves the effectiveness and utilization rate of nutrients in fertilizers, reducing nutrient loss and waste. Attached Figure Description
[0018] Figure 1 This is a graph showing the enzyme activity assay results of L-phenylalanine ammonia-lyase in tomato leaves in Example 4.
[0019] Figure 2 This is a graph showing the expression levels of the NRP1 gene in different parts of tomato in Example 4.
[0020] Figure 3 This is a diagram showing the expression levels of the PR-1 gene in different parts of tomato in Example 4.
[0021] Figure 4 This is a photograph of tomatoes after applying the combined water-soluble fertilizer from Example 1. Detailed Implementation
[0022] The present invention will be further described below with reference to the embodiments and accompanying drawings.
[0023] Example 1
[0024] The preparation method of the combined water-soluble fertilizer containing citric acid with immune-activating function in Example 1 includes the following steps:
[0025] I. Preparation of Citric Acid Nanoliposomes
[0026] Soybean lecithin, cholesterol, and DSPE-PEG2000 were mixed in a molar ratio of 60:35:5 and dissolved in ethanol to obtain an oil phase with a concentration of 6 mg / mL. 20 mg of citric acid was mixed with 50 mL of water to obtain an aqueous phase. The oil and aqueous phases were then thoroughly mixed, and the solvent was removed by rotary evaporation at 50 °C and 200 rpm. The mixture was then dialyzed through a 14 kDa membrane for 24 h and filtered through a 0.22 μm filter to obtain the final product. The citric acid nanoliposomes had a particle size of 100 nm.
[0027] II. Preparation of NPK coated with modified sodium alginate
[0028] Sodium alginate was dissolved in water to prepare a 3% sodium alginate solution. 10g of chitosan was added, and the solution was stirred until the pH was adjusted to 7. The solution was reacted at 80℃ for 2 hours. Then, impurities were removed by centrifugation, and the modified sodium alginate powder was obtained by freeze drying.
[0029] NPK raw material is granulated into particles with a diameter of 4 mm, and polyvinylpyrrolidone solution is sprayed on the surface of the particles to obtain NPK particles.
[0030] Modified sodium alginate was dissolved in water to obtain a 5% (w / w) modified sodium alginate solution. The modified sodium alginate solution was sprayed onto the surface of NPK particles at 40°C at a spraying rate of 8 mL / min. Then, a 2% (w / w) calcium chloride solution was sprayed for crosslinking for 10 min. Finally, the particles were dried at 40°C to obtain NPK coated with modified sodium alginate.
[0031] III. Preparation of Compound Probiotic Carriers
[0032] Organic matter such as straw and livestock manure is crushed to 2-5cm to obtain raw materials. The carbon-to-nitrogen ratio (C / N 30:1) is adjusted, and the moisture content is 65%. Then, it is processed according to a 10... 6 -10 7 CFU / g raw material was inoculated with Penicillium spore suspension and fermented for 10 days at 30℃ and pH 6 with intermittent aeration to obtain the first-stage product. The first-stage product was then cooled to 40℃, the pH was adjusted to 7, and fermented according to a 10 8 -10 9 The raw material with a concentration of CFU / g is inoculated with Bacillus subtilis culture and fermented facultatively at 40℃ for 3 days to obtain the product.
[0033] IV. Preparation of chelating solutions containing humic acid
[0034] Fermentation substrate was prepared by mixing 75% furfural residue, 15% crop straw, and 10% farmyard manure by mass percentage. The moisture content was controlled at 75%, and fermentation was carried out at 50℃. The mixture was turned over every 1-2 days until the humic acid content reached 70%. Then, a 2% potassium hydroxide solution was added at a mass ratio of 7:3, and the mixture was stirred at 80℃ for 2 hours. The humic acid supernatant was separated. The humic acid supernatant, 10 kg of EDTA-2Na, and 1 kg of sodium hydroxide were added to the reactor in sequence and stirred until completely dissolved. Then, 30 kg of zinc sulfate, 30 kg of manganese sulfate, 30 kg of copper sulfate, and 20 kg of ferrous sulfate were added in sequence and stirred for 60 minutes to allow the metal ions to combine with the chelating agent. Then, auxiliary components 30 kg of boric acid, 30 kg of ammonium molybdate, 10 kg of citric acid, and 5 kg of octyl-decyl glucoside (APG0810) were added and stirred until completely dissolved to form a homogeneous solution. The pH was adjusted to 6.5, and the solution was filtered to obtain a chelated solution containing humic acid.
[0035] V. Preparation of Combined Water-Soluble Fertilizers
[0036] 0.25 kg of citric acid nanoliposomes and 65 kg of modified sodium alginate-coated NPK were dissolved in 500 L of water. 0.8 kg of trans-cinnamic acid derivative and 4 kg of compound probiotic carrier were added. Humic acid chelate solution was added at 4 °C to obtain mixed raw materials. The mixed raw materials were added to 500 L of deionized water and stirred until completely dissolved. Undissolved impurities were removed by passing through a 200-mesh filter. 2 kg of sodium lignosulfonate was added to adjust the pH to 7, thus obtaining a combined water-soluble fertilizer containing citric acid with immune-activating function.
[0037] Example 2
[0038] The preparation method of the combined water-soluble fertilizer containing citric acid with immune-activating function in Example 2 includes the following steps:
[0039] I. Preparation of Citric Acid Nanoliposomes
[0040] Soybean lecithin, cholesterol, and DSPE-PEG2000 were mixed in a molar ratio of 60:35:5 and dissolved in ethanol to obtain an oil phase with a concentration of 6 mg / mL. 20 mg of citric acid was mixed with 50 mL of water to obtain an aqueous phase. The oil and aqueous phases were then thoroughly mixed, and the solvent was removed by rotary evaporation at 50 °C and 200 rpm. The mixture was then dialyzed through a 14 kDa membrane for 24 h and filtered through a 0.22 μm filter to obtain the final product. The citric acid nanoliposomes had a particle size of 100 mm.
[0041] II. Preparation of NPK coated with modified sodium alginate
[0042] Sodium alginate was dissolved in water to prepare a 5% sodium alginate solution. Then, 10g of chitosan was added, and the mixture was stirred until the pH was adjusted to 7. The mixture was reacted at 80℃ for 2 hours. After centrifugation to remove impurities, the modified sodium alginate powder was obtained by freeze drying.
[0043] NPK raw material is granulated into particles with a particle size of 2mm-2.5mm, and then polyvinylpyrrolidone solution is sprayed onto the surface of the particles to obtain NPK particles.
[0044] Modified sodium alginate was dissolved in water to obtain a 3% (w / w) modified sodium alginate solution. The modified sodium alginate solution was sprayed onto the surface of NPK particles at 60°C at a spraying rate of 5 mL / min. Then, a 3% (w / w) calcium chloride solution was sprayed for crosslinking for 25 min. Finally, it was dried at 50°C to obtain NPK coated with modified sodium alginate.
[0045] III. Preparation of Compound Probiotic Carriers
[0046] Organic matter such as straw and livestock manure is crushed to 2-5 cm to obtain raw materials. The carbon-to-nitrogen ratio (C / N 25:1) is adjusted, and the moisture content is 65%. Then, it is processed according to a 10... 6 -10 7 CFU / g raw material was inoculated with Penicillium spore suspension and fermented for 7 days at 25℃, pH 5.5, and intermittent aeration to obtain the first-stage product. The first-stage product was then cooled to 40℃, the pH was adjusted to 6, and fermented according to a 10... 8 -10 9 The substrate is inoculated with Bacillus subtilis culture and fermented at 42℃ for 5 days to obtain the product.
[0047] IV. Preparation of chelating solutions containing humic acid
[0048] Fermentation substrate was prepared by mixing 75% furfural residue, 15% crop straw, and 10% farmyard manure by mass percentage. The moisture content was controlled at 75%, and fermentation was carried out at 50℃. The mixture was turned over every 1-2 days until the humic acid content reached 70%. Then, a 2% potassium hydroxide solution was added at a mass ratio of 7:3, and the mixture was stirred at 80℃ for 2 hours. The humic acid supernatant was separated. The humic acid supernatant, 10 kg EDTA-2Na, and 1 kg sodium hydroxide were added to the reactor in sequence and stirred until completely dissolved. Then, 30 kg zinc sulfate, 30 kg manganese sulfate, 30 kg copper sulfate, and 20 kg ferrous sulfate were added in sequence and stirred for 60 minutes to allow the metal ions to combine with the chelating agent. Then, auxiliary components 30 kg boric acid, 30 kg ammonium molybdate, 10 kg citric acid, and 5 kg octyl-decyl glucoside (APG0810) were added and stirred until completely dissolved to form a homogeneous solution. The pH was adjusted to 6.5, and the solution was filtered to obtain a chelated solution containing humic acid.
[0049] V. Preparation of Combined Water-Soluble Fertilizers
[0050] 0.25 kg of citric acid nanoliposomes and 65 kg of modified sodium alginate-coated NPK were dissolved in 500 L of water. 0.8 kg of trans-cinnamic acid derivative and 4 kg of compound probiotic carrier were added. Humic acid chelate solution was added at 4 °C to obtain mixed raw materials. The mixed raw materials were added to 500 L of deionized water and stirred until completely dissolved. Undissolved impurities were removed by passing through a 200-mesh filter. 3 kg of sodium lignosulfonate was added to adjust the pH to 7, thus obtaining a combined water-soluble fertilizer containing citric acid with immune-activating function.
[0051] Example 3
[0052] The preparation method of the combined water-soluble fertilizer containing citric acid with immune-activating function in Example 3 includes the following steps:
[0053] I. Preparation of Citric Acid Nanoliposomes
[0054] Soybean lecithin, cholesterol, and DSPE-PEG2000 were mixed in a molar ratio of 60:35:5 and dissolved in ethanol to obtain an oil phase with a concentration of 6 mg / mL. 20 mg of citric acid was mixed with 50 mL of water to obtain an aqueous phase. The oil and aqueous phases were then thoroughly mixed, and the solvent was removed by rotary evaporation at 50 °C and 200 rpm. The mixture was then dialyzed through a 14 kDa membrane for 24 h and filtered through a 0.22 μm filter to obtain the final product. The citric acid nanoliposomes had a particle size of 100 mm.
[0055] II. Preparation of NPK coated with modified sodium alginate
[0056] Sodium alginate was dissolved in water to prepare a 3% sodium alginate solution. 10g of chitosan was added, and the solution was stirred until the pH was adjusted to 7. The solution was reacted at 80℃ for 2 hours. Then, impurities were removed by centrifugation, and the modified sodium alginate powder was obtained by freeze drying.
[0057] NPK raw material is granulated into particles with a particle size of 1mm-1.5mm, and then polyvinylpyrrolidone solution is sprayed onto the surface of the particles to obtain NPK particles.
[0058] Modified sodium alginate was dissolved in water to obtain a 6% (w / w) modified sodium alginate solution. The modified sodium alginate solution was sprayed onto the surface of NPK particles at 55°C at a spraying rate of 10 mL / min. Then, a 5% (w / w) calcium chloride solution was sprayed for crosslinking for 30 min, followed by drying at 60°C to obtain NPK coated with modified sodium alginate.
[0059] III. Preparation of Compound Probiotic Carriers
[0060] Organic matter such as straw and livestock manure is crushed to 2-5 cm to obtain raw materials. The carbon-to-nitrogen ratio (C / N 26:1) is adjusted, and the moisture content is 65%. Then, it is processed according to a 10... 6 -10 7 CFU / g raw material was inoculated with Penicillium spore suspension and fermented for 9 days at 25℃, pH 5.5, and with intermittent aeration to obtain the first-stage product. The first-stage product was then cooled to 45℃, the pH was adjusted to 7, and fermented according to a 10... 8 -10 9 The raw material with a concentration of CFU / g is inoculated with Bacillus subtilis culture and fermented at 45℃ for 5 days in a facultative anaerobic environment to obtain the final product.
[0061] IV. Preparation of chelating solutions containing humic acid
[0062] Fermentation substrate was prepared by mixing 75% furfural residue, 15% crop straw, and 10% farmyard manure by mass percentage. The moisture content was controlled at 75%, and the fermentation was carried out at 50℃. The mixture was turned over every 1-2 days until the humic acid content reached 70%. Then, a 2% potassium hydroxide solution was added at a mass ratio of 7:3, and the mixture was stirred at 800℃ for 2 hours. The humic acid supernatant was separated. The humic acid supernatant, 10 kg EDTA-2Na, and 1 kg sodium hydroxide were added to the reactor in sequence and stirred until completely dissolved. Then, 30 kg zinc sulfate, 30 kg manganese sulfate, 30 kg copper sulfate, and 20 kg ferrous sulfate were added in sequence and stirred for 60 minutes to allow the metal ions to combine with the chelating agent. Then, auxiliary components 30 kg boric acid, 30 kg ammonium molybdate, 10 kg citric acid, and 5 kg octyl-decyl glucoside (APG0810) were added and stirred until completely dissolved to form a homogeneous solution. The pH was adjusted to 6.5, and the solution was filtered to obtain a chelated solution containing humic acid.
[0063] V. Preparation of Combined Water-Soluble Fertilizers
[0064] 0.25 kg of citric acid nanoliposomes and 65 kg of modified sodium alginate-coated NPK were dissolved in 500 L of water. 0.8 kg of trans-cinnamic acid derivative and 4 kg of compound probiotic carrier were added. Humic acid chelate solution was added at 4 °C to obtain mixed raw materials. The mixed raw materials were added to 500 L of deionized water and stirred until completely dissolved. Undissolved impurities were removed by passing through a 200-mesh filter. 2 kg of sodium lignosulfonate was added to adjust the pH to 7, thus obtaining a combined water-soluble fertilizer containing citric acid with immune-activating function.
[0065] Example 4
[0066] The combined water-soluble fertilizer in Example 1 was applied at three stages of tomato cultivation:
[0067] 1. 15 days after transplanting: Add 50mL of the combined water-soluble fertilizer to 15kg of water for root irrigation to activate NPR1 gene expression.
[0068] 2. Flowering and fruit setting period: Add 1 mL of 0.02% polyglycerol penetrant to the combined water-soluble fertilizer, and add 30 mL of water-soluble fertilizer to 15 kg of water for foliar spraying to induce PR protein synthesis.
[0069] 3. Fruit enlargement period: Add 50mL of the combined water-soluble fertilizer to 15kg of water for foliar spraying to promote lycopene accumulation.
[0070] The results of the determination of L-phenylalanine ammonia-lyase activity and coumaric acid content in tomatoes are shown in Table 1 and 2. Figure 1 As shown, from Figure 1 It can be seen that, compared with tomatoes that have not been treated with the combined water-soluble fertilizer, the enzyme activity of L-phenylalanine ammonia-lyase in tomato leaves treated with the combined water-soluble fertilizer is significantly increased. Figures 1-4 In the diagram, CK represents tomato samples that were not treated with the combined water-soluble fertilizer of this invention, and N represents tomato samples that were treated with the combined water-soluble fertilizer of this invention.
[0071] Table 1. Results of coumaric acid content determination in tomatoes (%, N=3)
[0072] 202405-01 0.000281 202405-02 0.000263 202405-03 0.000255 202405-04 0.000365 202405-05 0.000312 202405-06 0.000345
[0073] The results of NRP1 gene detection in tomatoes are as follows: Figure 2 As shown, from Figure 2 As can be seen, the expression level of the NRP1 gene in the roots, stems, and leaves of tomatoes treated with the combined water-soluble fertilizer of Example 1 increased significantly. Figure 3 It can be seen that the combined water-soluble fertilizer in Example 1 can induce the expression of the PR-1 gene in different parts of tomatoes, increasing the PR-1 gene in tomato flowers, roots, stems, leaves and fruits.
[0074] Experimental Example 1
[0075] Test of sustained-release performance of modified sodium alginate-coated NPK in Example 1
[0076] Reference standard: GB / T 23348-2021;
[0077] Test method: static water extraction;
[0078] Each group of fertilizer samples was placed in deionized water at 25℃, and the cumulative dissolution rate of nitrogen, phosphorus, and potassium in the water was measured periodically. In Table 2-5, A is a common 15-15-15 NPK compound fertilizer, and B is a modified sodium alginate-coated NPK fertilizer.
[0079] Table 2. Cumulative nitrogen release rate
[0080]
[0081] Table 3. Cumulative phosphorus release rate
[0082]
[0083] Table 4. Cumulative Potassium Release Rate
[0084]
[0085]
[0086] Experimental Example 2
[0087] Mechanical strength test of NPK coated with modified sodium alginate in Example 1
[0088] Using a particle crushing strength tester, 30 intact coated fertilizer particles were randomly selected and their crushing strength was measured. The average value was then taken.
[0089] Table 5. Test results of mechanical strength properties
[0090] Average crushing force (N) 22.7±2.8 35.4±3.2 Coating layer abrasion resistance (weight loss rate %) 8.50％ 3.20％
Claims
1. A combination water-soluble fertilizer containing citric acid and possessing immune-activating function, characterized in that, The composition, by weight percentage, includes 0.25-0.3% citric acid nanoliposomes, 60-65% NPK coated with modified sodium alginate, 4-6% compound probiotic carrier, 0.8-1% trans-cinnamic acid derivative, 2-3% sodium lignosulfonate, and the remainder being a chelate containing humic acid.
2. The combined water-soluble fertilizer containing citric acid and possessing immune-activating function according to claim 1, characterized in that, The citric acid nanoliposomes have a particle size of 80-120 nm. The preparation method of the citric acid nanoliposomes is as follows: soybean lecithin, cholesterol and DSPE-PEG2000 are mixed and dissolved in ethanol to obtain an oil phase, citric acid is dissolved in water to obtain an aqueous phase, the oil phase and the aqueous phase are mixed and the solvent is removed by rotary evaporation to obtain the final product.
3. The combined water-soluble fertilizer containing citric acid and possessing immune-activating function according to claim 2, characterized in that, The molar ratio of soybean lecithin, cholesterol and DSPE-PEG2000 is 60:35:5, and the concentration of the oil phase is 6 mg / mL. The concentration of the aqueous phase is 0.4 mg / mL.
4. The combined water-soluble fertilizer containing citric acid and possessing immune-activating function according to claim 1, characterized in that, The method for preparing the modified sodium alginate-coated NPK is as follows: the modifier is mixed with sodium alginate solution, the pH is adjusted to neutral, the reaction is carried out at 80°C for 2 hours, and the modified sodium alginate is obtained after centrifugation and drying; the NPK raw material is granulated to obtain NPK particles. Modified sodium alginate is dissolved in a solvent to obtain a modified sodium alginate solution. The modified sodium alginate solution is sprayed onto the surface of NPK particles, followed by the spraying of calcium chloride solution for cross-linking, curing, and drying to obtain the final product.
5. The combined water-soluble fertilizer containing citric acid and possessing immune-activating function according to claim 4, characterized in that, The sodium alginate solution has a mass fraction of 2-5%, the modifier is chitosan or nano-clay, and the mass ratio of sodium alginate to the modifier is 100:10; the mass ratio of N, P, and K in the NPK raw material is 10:4:6; the mass fraction of the modified sodium alginate solution is 3-8%; the spraying temperature of the modified sodium alginate solution onto the surface of NPK particles is 40-60℃, and the spraying rate is 5-15 mL / min; the mass fraction of the calcium chloride solution is 2-6%, and the crosslinking time is 10-40 min.
6. The combined water-soluble fertilizer containing citric acid and possessing immune-activating function according to claim 1, characterized in that, The preparation method of the compound probiotic carrier is as follows: straw and livestock manure are crushed to 2-5cm to obtain raw materials, the carbon-nitrogen ratio is adjusted to 25-30:1, the water content is 60-65%, and then Penicillium spore suspension is inoculated for aerobic fermentation to obtain the first stage product; the first stage product is cooled to 40-45℃, the pH is adjusted to 6.5-7.5, and then Bacillus subtilis bacterial solution is inoculated for facultative anaerobic fermentation to obtain the final product.
7. The combined water-soluble fertilizer containing citric acid and possessing immune-activating function according to claim 6, characterized in that, The inoculation amount of the Penicillium spore suspension was 10. 6 -10 7 The aerobic fermentation conditions are: temperature 25-30℃, pH 5.5-6.5, and time 7-10 days; the inoculum size of the Bacillus subtilis culture is 10 CFU / g. 8 -10 9 The facultative anaerobic fermentation is carried out at a temperature of 35-45℃ for 3-5 days, with a yield of CFU / g of raw material.
8. The combined water-soluble fertilizer containing citric acid and possessing immune-activating function according to claim 1, characterized in that, The preparation method of the humic acid-containing chelate is as follows: Fermentation is carried out using furfural residue, crop straw and farmyard manure as base materials until the humic acid content is ≥70%. Then, alkaline solution is added, and after centrifugation, humic acid supernatant is obtained. The humic acid supernatant, EDTA-2Na and sodium hydroxide are mixed and stirred until completely dissolved. Zinc ions, manganese ions, copper ions and ferrous ions are added in sequence, and the pH is adjusted to 6.
5. After filtration, humic acid-containing chelate is obtained.
9. A method for preparing a combined water-soluble fertilizer containing citric acid with immune-activating function as described in claim 1, characterized in that, The process includes the following steps: mixing the prescribed amount of citric acid nanoliposomes with NPK coated with modified sodium alginate and dissolving them in water; sequentially adding trans-cinnamic acid derivatives and a complex probiotic carrier; adding humic acid-containing chelated liquid at 4-6°C; and adjusting the pH to 7 with sodium lignosulfonate.
10. The application of a combined water-soluble fertilizer containing citric acid with immune-activating function as described in claim 1 in regulating the phenylpropanoid metabolic pathway in tomatoes.