Preparation method of degradable seedling support for enhancing immune function of vegetables

Abstract

The invention discloses a preparation method of a degradable seedling support with a vegetable immunity enhancing function. The preparation method comprises the following steps: step 1, preparing a seedling support raw material; step 2, preparing a polypyrrole-polycaprolactone compound; and step 3, preparing the seedling support raw material into a seedling support outer layer, arranging a seedling support inner layer prepared from the polypyrrole-polycaprolactone compound in the seedling support outer layer, connecting the seedling support outer layer with a micro biological battery, arranging a plurality of conductive circuits prepared from the polypyrrole-polycaprolactone compound in the seedling support inner layer, and connecting the seedling support inner layer with the micro biological battery. And finally, preparing the degradable seedling support with the function of enhancing the immune function of the vegetables. By introducing the biodegradable conductive polymer, bioelectrical stimulation is provided for vegetable roots, growth and development of vegetables are promoted, and the immune function of the vegetables is enhanced.

Description

Technical Field

[0001] The invention relates to the technical field of seedling trays, and more specifically to a method for preparing a degradable seedling tray capable of enhancing vegetable immunity. Background Art

[0002] Fruits and vegetables are an indispensable and important part of people's daily diet, and their yield and quality are directly related to people's quality of life and health. In the process of vegetable planting, seedling cultivation is a key link. High-quality seedling cultivation can lay a good foundation for vegetable growth and significantly improve the survival rate, growth rate and disease and pest resistance of vegetables. However, the common seedling trays currently have problems such as non-degradable materials and single functions. In the prior art, for example, an invention patent application with application publication number CN105746226A discloses a method for preparing a biomass degradable seedling tray. Although the problem of non-degradable materials is solved, the seedling tray only plays a simple role of supporting and fixing the seedlings, lacks the effect of enhancing the immune function of vegetables, and cannot provide additional protection mechanisms for vegetables. There is still room for improvement. Summary of the invention

[0003] One object of the present invention is to provide a method for preparing a degradable seedling tray having the function of enhancing the immune function of vegetables, which can not only achieve biodegradation and reduce soil pollution, but also enhance the immune function of vegetables and promote the healthy growth of vegetables.

[0004] In order to achieve these purposes and other advantages of the present invention, according to one aspect of the present invention, the present invention provides a method for preparing a degradable seedling tray having the function of enhancing vegetable immunity, comprising the following steps: Step 1: prepare corn stalk fiber, crush it into a particle size of 1-3 mm, dry it, add a gelatinized corn starch solution with a mass fraction of 15-20%, stir it evenly, and prepare a seedling support raw material, wherein the mass ratio of the corn stalk fiber to the corn starch is (5-8):2; Step 2: dissolving the polycaprolactone solution in chloroform to prepare a solution with a mass fraction of 10-15%, adding polypyrrole, and magnetically stirring at 50-60° C. for 6-8 hours to obtain a polypyrrole-polycaprolactone complex; Step three, the seedling tray raw material is made into a seedling tray outer layer, an inner layer of the seedling tray made of the polypyrrole-polycaprolactone composite is arranged inside the outer layer of the seedling tray, and a micro-biobattery is connected, and a plurality of conductive circuits made of the polypyrrole-polycaprolactone composite are arranged inside the inner layer of the seedling tray, and finally the degradable seedling tray with enhanced vegetable immunity is obtained.

[0005] The micro biobattery can be made according to the principle of microbial fuel cells. Specifically, 3D printing technology can be used to make a microbattery shell with polylactic acid as the material, and a proton exchange membrane can be used to separate the inside of the microbattery shell into an anode chamber and a cathode chamber. Graphite felt is placed in the anode chamber as an anode, and the anode is immersed in the bacterial liquid of electricity-producing microorganisms such as Geobacter, Shewanella, and Bacillus. A platinum-carbon electrode is placed in the cathode chamber as a cathode, and a cathode electrolyte is injected to assemble a microbial battery.

[0006] Preferably, the molecular weight of the polycaprolactone in step 2 is 10,000-20,000.

[0007] Preferably, the molecular weight of the polypyrrole in step 2 is 100,000-200,000.

[0008] Preferably, in step three, the degradable seedling tray having the function of enhancing vegetable immunity is made by using 3D printing technology, and the specific steps are as follows: Step A: According to the requirements of vegetable seedling cultivation, a 3D model of the seedling tray is designed using CAD software, and the direction and distribution of the conductive lines inside the seedling tray are designed; Step B, loading the seedling support raw material and the polypyrrole-polycaprolactone composite into the barrel of a double-nozzle 3D printer, setting the printing temperature to 180-200° C., the printing speed to 30-50 mm / s, the seedling support outer layer thickness to 0.2-0.3 mm, the seedling support inner layer thickness to 0.05-0.1 mm, and the conductive circuit diameter to 0.1-0.2 mm; Step C, starting the 3D printer, printing layer by layer according to the set model and parameters, drying and polishing after printing, and finally obtaining the degradable seedling tray with the function of enhancing vegetable immunity.

[0009] Preferably, the conductive lines extend radially from the center to the edge at the bottom of the inner layer of the seedling holder, and are distributed in a grid pattern in the middle of the inner layer of the seedling holder, with a grid spacing of 5-8 mm.

[0010] Preferably, the outer layer thickness of the seedling support is 0.25 mm, and the inner layer thickness of the seedling support is 0.08 mm.

[0011] Preferably, the diameter of the conductive line is 0.15 mm.

[0012] Preferably, in step one, the mass ratio of corn stalk fiber to corn starch is 3:1.

[0013] The present invention includes at least the following beneficial effects: the preparation method of the degradable seedling tray with enhanced vegetable immune function provided by the present invention can not only solve the environmental pollution problem caused by traditional seedling trays, but also promote the growth and development of vegetable roots, enhance the immune ability of vegetables themselves, reduce the use of chemical pesticides, and realize green and sustainable production of vegetables.

[0014] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below through specific implementation modes so that those skilled in the art can implement the invention with reference to the description.

[0016] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0017] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0018] Example 1 A method for preparing a degradable seedling support capable of enhancing vegetable immunity comprises the following steps: Step 1: Collect corn stalks, remove impurities, and crush them into particles with a diameter of 1-3 mm. Place the crushed corn stalk fibers in an oven and dry them at 80° C. to a constant weight for later use. Step 2: Take corn starch, add an appropriate amount of water, prepare a corn starch solution with a mass fraction of 18%, and gelatinize the solution under heating and stirring conditions until a uniform gelatinized corn starch solution is formed; Step 3: adding the prepared corn stalk fiber to the gelatinized corn starch solution, and stirring the mixture evenly with a stirrer to prepare a seedling support material, wherein the mass ratio of the corn stalk fiber to the corn starch is 3:1; Step 4: Take polycaprolactone with a molecular weight of 15,000, dissolve it in chloroform to prepare a polycaprolactone solution with a mass fraction of 10%, add polypyrrole with a molecular weight of 150,000, place the mixed solution in a constant temperature water bath at 55°C, and use a magnetic stirrer to stir at a speed of 300 r / min for 7 hours to obtain a polypyrrole-polycaprolactone complex; Step 5. According to the requirements of common leafy vegetable seedlings, use CAD software to design a 3D model of the seedling tray. Design the conductive circuit to extend radially from the center to the edge at the bottom of the inner layer of the seedling tray, and distribute it in a grid pattern in the middle of the inner layer of the seedling tray. The grid spacing is set to 6 mm. The prepared seedling tray raw material and polypyrrole-polycaprolactone composite are respectively loaded into the two barrels of the dual-nozzle 3D printer, and the printing temperature is set to 190℃, the printing speed is set to 40mm / s, the seedling tray outer layer thickness is set to 0.25 mm, the seedling tray inner layer thickness is set to 0.08 mm, and the conductive circuit diameter is 0.15 mm; Step 6. Start the 3D printer and print layer by layer according to the set model and parameters. After printing, place the seedling tray in an oven and dry it at 60°C for 2 hours to remove the residual solvent. Then use sandpaper to polish the surface of the seedling tray to make it smooth. Install the micro-biobattery to connect it to the inner layer of the seedling tray, and finally produce a degradable seedling tray with enhanced vegetable immunity.

[0019] Example 2 A method for preparing a degradable seedling support capable of enhancing vegetable immunity comprises the following steps: Step 1: Collect corn stalks, remove impurities, and crush them into particles with a diameter of 1-3 mm. Place the crushed corn stalk fibers in an oven and dry them at 80° C. to a constant weight for later use. Step 2: Take corn starch, add an appropriate amount of water to prepare a corn starch solution with a mass fraction of 20%, and gelatinize the solution under heating and stirring conditions until a uniform gelatinized corn starch solution is formed; Step 3: Add the prepared corn stalk fiber to the gelatinized corn starch solution, and stir well with a stirrer to prepare a seedling support material, wherein the mass ratio of the corn stalk fiber to the corn starch is 5:2; Step 4: Take polycaprolactone with a molecular weight of 20,000, dissolve it in chloroform to prepare a polycaprolactone solution with a mass fraction of 15%, add polypyrrole with a molecular weight of 200,000, place the mixed solution in a constant temperature water bath at 60°C, and use a magnetic stirrer to stir at a speed of 300 r / min for 8 hours to obtain a polypyrrole-polycaprolactone complex; Step 5. According to the requirements of common leafy vegetable seedlings, use CAD software to design a 3D model of the seedling tray. Design the conductive circuit to extend radially from the center to the edge at the bottom of the inner layer of the seedling tray, and distribute it in a grid pattern in the middle of the inner layer of the seedling tray. The grid spacing is set to 8 mm. The prepared seedling tray raw material and polypyrrole-polycaprolactone composite are respectively loaded into the two barrels of the dual-nozzle 3D printer, and the printing temperature is set to 200℃, the printing speed is set to 50mm / s, the seedling tray outer layer thickness is set to 0.2 mm, the seedling tray inner layer thickness is set to 0.1 mm, and the conductive circuit diameter is 0.2 mm; Step 6. Start the 3D printer and print layer by layer according to the set model and parameters. After printing, place the seedling tray in an oven and dry it at 60°C for 2 hours to remove the residual solvent. Then use sandpaper to polish the surface of the seedling tray to make it smooth. Install the micro-biobattery to connect it to the inner layer of the seedling tray, and finally produce a degradable seedling tray with enhanced vegetable immunity.

[0020] Example 3 A method for preparing a degradable seedling support capable of enhancing vegetable immunity comprises the following steps: Step 1: Collect corn stalks, remove impurities, and crush them into particles with a diameter of 1-3 mm. Place the crushed corn stalk fibers in an oven and dry them at 80° C. to a constant weight for later use. Step 2: Take corn starch, add an appropriate amount of water, prepare a corn starch solution with a mass fraction of 15%, and gelatinize the solution under heating and stirring conditions until a uniform gelatinized corn starch solution is formed; Step 3: adding the prepared corn stalk fiber to the gelatinized corn starch solution, and stirring the mixture evenly with a stirrer to prepare a seedling support material, wherein the mass ratio of the corn stalk fiber to the corn starch is 4:1; Step 4: Take polycaprolactone with a molecular weight of 15,000, dissolve it in chloroform to prepare a polycaprolactone solution with a mass fraction of 10%, add polypyrrole with a molecular weight of 100,000, place the mixed solution in a constant temperature water bath at 50°C, and use a magnetic stirrer to stir at a speed of 300 r / min for 6 hours to obtain a polypyrrole-polycaprolactone complex; Step 5. According to the requirements of common leafy vegetable seedlings, use CAD software to design a 3D model of the seedling tray. Design the conductive circuit to extend radially from the center to the edge at the bottom of the inner layer of the seedling tray, and distribute it in a grid pattern in the middle of the inner layer of the seedling tray. The grid spacing is set to 5 mm. The prepared seedling tray raw materials and polypyrrole-polycaprolactone composite are respectively loaded into the two barrels of the dual-nozzle 3D printer, and the printing temperature is set to 180℃, the printing speed is set to 30mm / s, the seedling tray outer layer thickness is set to 0.3 mm, the seedling tray inner layer thickness is set to 0.05 mm, and the conductive circuit diameter is 0.2 mm; Step 6. Start the 3D printer and print layer by layer according to the set model and parameters. After printing, place the seedling tray in an oven and dry it at 60°C for 2 hours to remove the residual solvent. Then use sandpaper to polish the surface of the seedling tray to make it smooth. Install the micro-biobattery to connect it to the inner layer of the seedling tray, and finally produce a degradable seedling tray with enhanced vegetable immunity.

[0021] Comparative Example 1 A method for preparing a seedling tray comprises the following steps: Step 1: Collect corn stalks, remove impurities, and crush them into particles with a diameter of 1-3 mm. Place the crushed corn stalk fibers in an oven and dry them at 80° C. to a constant weight for later use. Step 2: Take corn starch, add an appropriate amount of water, prepare a corn starch solution with a mass fraction of 18%, and gelatinize the solution under heating and stirring conditions until a uniform gelatinized corn starch solution is formed; Step 3: adding the prepared corn stalk fiber to the gelatinized corn starch solution, and stirring the mixture evenly with a stirrer to prepare a seedling support material, wherein the mass ratio of the corn stalk fiber to the corn starch is 3:1; Step 4: According to the requirements for raising seedlings of common leafy vegetables, use CAD software to design a 3D model of the seedling tray, load the prepared seedling tray raw materials into the barrel of the 3D printer, set the printing temperature to 190°C, the printing speed to 40mm / s, and the seedling tray layer thickness to 0.3 mm; Step 5: Start the 3D printer and print layer by layer according to the set model and parameters. After printing, place the seedling tray in an oven and dry it at 60°C for 2 hours to remove the residual solvent. Then use sandpaper to polish the surface of the seedling tray to make it smooth to obtain the seedling tray.

[0022] Comparative Example 2 A method for preparing a seedling tray comprises the following steps: Step 1: Collect corn stalks, remove impurities, and crush them into particles with a diameter of 1-3 mm. Place the crushed corn stalk fibers in an oven and dry them at 80° C. to a constant weight for later use. Step 2: Take corn starch, add an appropriate amount of water, prepare a corn starch solution with a mass fraction of 18%, and gelatinize the solution under heating and stirring conditions until a uniform gelatinized corn starch solution is formed; Step 3: adding the prepared corn stalk fiber to the gelatinized corn starch solution, and stirring the mixture evenly with a stirrer to prepare a seedling support material, wherein the mass ratio of the corn stalk fiber to the corn starch is 3:1; Step 4: Take polycaprolactone with a molecular weight of 15,000, dissolve it in chloroform to prepare a polycaprolactone solution with a mass fraction of 10%, add polypyrrole with a molecular weight of 150,000, place the mixed solution in a constant temperature water bath at 55°C, and use a magnetic stirrer to stir at a speed of 300 r / min for 7 hours to obtain a polypyrrole-polycaprolactone complex; Step 5. Design the 3D model of the seedling tray using CAD software according to the requirements of common leafy vegetable seedlings. Load the prepared seedling tray raw material and polypyrrole-polycaprolactone composite into the two barrels of the dual-nozzle 3D printer respectively, set the printing temperature to 190°C, the printing speed to 40mm / s, the outer layer thickness of the seedling tray to 0.25 mm, and the inner layer thickness of the seedling tray to 0.08 mm; Step 6: Start the 3D printer and print layer by layer according to the set model and parameters. After printing, place the seedling tray in an oven and dry it at 60°C for 2 hours to remove the residual solvent. Then use sandpaper to polish the surface of the seedling tray to make it smooth, install the micro-biobattery to connect it to the inner layer of the seedling tray, and finally make the seedling tray.

[0023] Vegetable growth index determination Take the seedling trays prepared in Examples 1-3 and Comparative Examples 1-2, put the same amount of planting soil in them, sow rapeseeds, sow 3-5 seeds per hole, and after the seeds germinate, retain a healthy seedling, observe and measure its growth indicators, including: Plant height measurement: Starting from the emergence of the seedlings, the plant height of the seedlings was measured every 3 days using a ruler, and the data of each measurement was recorded to observe the effects of different seedling trays on the growth rate of vegetables. The results are shown in Table 1.

[0024] Table 1 Stem diameter measurement: On the 10th, 15th and 20th day of seedling growth, the diameter of the base of the seedling stem was measured using a vernier caliper, and the stem diameter data was recorded to evaluate the effect of the seedling tray on the development of vegetable stems. The results are shown in Table 2.

[0025] Table 2 Immune function index determination Take the seedling trays prepared in Examples 1-3 and Comparative Examples 1-2, put the same amount of planting soil in them, sow rapeseeds, sow 3-5 seeds per hole, and after the seeds germinate, retain a healthy seedling, observe and measure its immune function indicators, including: Antioxidant enzyme activity determination: Leaf samples were collected at different stages of vegetable growth, such as seedling stage, growth stage and maturity stage. The activity of peroxidase (POD) was determined by the kit method. Peroxidase plays an important role in plants' resistance to external stress and enhancement of immune function, and its activity can reflect the immune capacity of vegetables. The results are shown in Table 3.

[0026] Table 3 Seedling stage Growth period Maturity Example 1 POD activity (U / g FW) 283.1 ± 11.0 353.4 ± 13.2 303.2 ± 12.0 Example 2 POD activity (U / g FW) 280.5 ± 10.2 350.8 ± 12.5 300.6 ± 11.0 Example 3 POD activity (U / g FW) 278.3 ± 9.5 348.6 ± 11.8 298.4 ± 10.5 Comparative Example 1 POD activity (U / g FW) 218.4 ± 8.0 278.2 ± 9.8 238.3 ± 9.0 Comparative Example 2 POD activity (U / g FW) 262.7 ± 9.0 303.5 ± 11.2 282.6 ± 10.0 Determination of plant hormone content: Leaf samples were also collected at different growth stages, and the content of plant hormone salicylic acid was determined using high performance liquid chromatography (HPLC). Salicylic acid (SA) is involved in the defense response of plants, and changes in its content can reflect the enhancement of vegetable immune function. The results are shown in Table 4.

[0027] Table 4 Seedling stage Growth period Maturity Example 1 SA content (ng / g FW) 122.1 ± 5.5 182.3 ± 7.5 152.7 ± 6.5 Example 2 SA content (ng / g FW) 120.5 ± 5.0 180.8 ± 7.0 150.6 ± 6.0 Example 3 SA content (ng / g FW) 118.3 ± 4.5 178.6 ± 6.5 148.4 ± 5.5 Comparative Example 1 SA content (ng / g FW) 78.3 ± 3.2 118.4 ± 5.0 98.3 ± 4.0 Comparative Example 2 SA content (ng / g FW) 100.5 ± 3.5 140.6 ± 5.5 120.5 ± 4.5 The results show that the seedling trays prepared by the method of the present invention in Examples 1-3 have a positive effect on the growth of vegetables and can enhance the immune function of vegetables. The plant height and stem thickness of the seedlings cultivated therein, as well as the antioxidant enzyme activity and salicylic acid content are better than those of Comparative Examples 1 and 2. This is mainly because the conductive inner layer and conductive circuit formed by the micro-biobattery and the polypyrrole-polycaprolactone complex can generate an appropriate amount of current, stimulate the change of the permeability of the plant root cell membrane, promote the absorption of potassium and calcium ions, and regulate the synthesis and transportation of plant hormones, thereby affecting the photosynthesis, respiration and other physiological processes of the plant, promoting plant growth, and improving the immune function of the plant. The conductive circuit is designed according to the distribution of the vegetable root system, so that the conductive circuit is in full contact with the vegetable root system, and the stimulation to the plant root system is improved. However, the seedling tray prepared in Comparative Example 1 only uses corn stalk fiber and corn starch as degradable materials, which will not produce the effect of promoting vegetable growth and development and enhancing immune function. In Comparative Example 2, only the conductive inner layer is provided inside the seedling support, which is far away from the root system of the vegetables and has a limited range of action, resulting in limited effects on promoting the growth and development of vegetables and enhancing the immune function.

[0028] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the examples shown and described herein.

Claims

1. A method for preparing a degradable seedling tray capable of enhancing the immune function of vegetables, characterized in that: The following steps are involved: Step 1: prepare corn stalk fiber, crush it into a particle size of 1-3 mm, dry it, add a gelatinized corn starch solution with a mass fraction of 15-20%, stir it evenly, and prepare a seedling support raw material, wherein the mass ratio of the corn stalk fiber to the corn starch is (5-8):2; Step 2: dissolving the polycaprolactone solution in chloroform to prepare a solution with a mass fraction of 10-15%, adding polypyrrole, and magnetically stirring at 50-60° C. for 6-8 hours to obtain a polypyrrole-polycaprolactone complex; Step three, the seedling tray raw material is made into a seedling tray outer layer, an inner layer of the seedling tray made of the polypyrrole-polycaprolactone composite is arranged inside the outer layer of the seedling tray, and a micro-biobattery is connected, and a plurality of conductive circuits made of the polypyrrole-polycaprolactone composite are arranged inside the inner layer of the seedling tray, and finally the degradable seedling tray with enhanced vegetable immunity is obtained.

2. The method for preparing the degradable seedling tray having the function of enhancing vegetable immunity according to claim 1, characterized in that: The molecular weight of the polycaprolactone in the step 2 is 10000-20000.

3. The method for preparing the degradable seedling support capable of enhancing the vegetable immunity according to claim 1, characterized in that: The molecular weight of the polypyrrole in step 2 is 100,000-200,000.

4. The method for preparing the degradable seedling support capable of enhancing the vegetable immunity according to claim 1, characterized in that: In the step 3, the degradable seedling tray with enhanced vegetable immunity function is made by using 3D printing technology, and the specific steps are: Step A: According to the requirements of vegetable seedling cultivation, a 3D model of the seedling tray is designed using CAD software, and the direction and distribution of the conductive lines inside the seedling tray are designed; Step B, loading the seedling support raw material and the polypyrrole-polycaprolactone composite into the barrel of a double-nozzle 3D printer, setting the printing temperature to 180-200° C., the printing speed to 30-50 mm / s, the seedling support outer layer thickness to 0.2-0.3 mm, the seedling support inner layer thickness to 0.05-0.1 mm, and the conductive circuit diameter to 0.1-0.2 mm; Step C, starting the 3D printer, printing layer by layer according to the set model and parameters, drying and polishing after printing, and finally obtaining the degradable seedling tray with the function of enhancing vegetable immunity.

5. The method for preparing the degradable seedling support capable of enhancing the vegetable immunity according to claim 4, characterized in that: The conductive lines extend radially from the center to the edge at the bottom of the inner layer of the seedling holder, and are distributed in a grid shape in the middle of the inner layer of the seedling holder, with a grid spacing of 5-8 mm.

6. The method for preparing the degradable seedling tray having the function of enhancing vegetable immunity according to claim 4, characterized in that: The thickness of the outer layer of the seedling support is 0.25 mm, and the thickness of the inner layer of the seedling support is 0.08 mm.

7. The method for preparing the degradable seedling support capable of enhancing vegetable immunity according to claim 4, characterized in that: The diameter of the conductive line is 0.15 mm.

8. The method for preparing the degradable seedling tray capable of enhancing the immune function of vegetables according to claim 1, characterized in that: In the step 1, the mass ratio of corn stalk fiber to corn starch is 3:1.

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