A seed soaking solution and its preparation method

Abstract

The present invention relates to the technical field of crop seed soaking, and specifically relates to a seed soaking solution and a preparation method thereof. The seed soaking solution is composed of the following raw materials: modified nano-zinc oxide, hydrogen peroxide, ascorbic acid, polyacrylate-metal composite material, seaweed extract, potassium dihydrogen phosphate, proline, polysorbate-20, and polyethylene glycol. In the present invention, the polyacrylate-metal composite material, modified nano-zinc oxide, hydrogen peroxide, and ascorbic acid act through a synergistic effect. The polyacrylate-metal composite material serves as a carrier to effectively adsorb various nutrient components and prevent the aggregation of modified nano-zinc oxide, promoting the catalytic conversion of nutrient components. Hydrogen peroxide opens the internal channels of the seeds, and the modified nano-zinc oxide carrying the nutrient components directly enters the seeds. At the same time, reactive oxygen species and Zn<supgt;2+< / supgt; are generated, activating enzymes and thus increasing the seed metabolic rate. Ascorbic acid scavenges excessive reactive oxygen species and, together with the polyacrylate-metal composite material, reduces the heavy metal content in the solution.

Description

Technical Field

[0001] The present invention relates to the technical field of crop seed soaking, and specifically to a seed soaking solution and a preparation method thereof. Background Art

[0002] A seed soaking solution is a special solution used to treat seeds. The solution usually contains various growth regulators, nutrient elements, organic substances and other beneficial substances, aiming to improve the germination rate, growth potential and overall health of plants. As a simple and effective seed treatment method, seed soaking technology is widely used in agricultural production. The seed soaking solution can soften the seed coat, promote the absorption of water and oxygen, accelerate the seed germination process, and improve the germination rate; it can provide the nutrients and growth regulators required for the initial growth of seedlings, thereby enhancing the seedling vitality and early growth of seedlings; it can also enhance the resistance of seeds to adverse environments, such as drought resistance, cold resistance, salt-alkali resistance, etc., thereby improving the stress resistance of crops; at the same time, it can stimulate root growth, improve the absorption capacity of plants for water and nutrients, and promote the root development of crops; the seed soaking solution also has bactericidal and insecticidal effects, and can prevent diseases and insect pests in the seed and seedling stages. However, the absorption efficiency of seeds for the nutrients in the seed soaking solution still needs to be improved. In order to improve the absorption of the effective components in the soaking solution by seeds, natural active substances such as seaweed extracts are used to optimize the formula and introduce nanotechnology to improve the utilization rate and biological activity of the effective components of the seed soaking solution, promote the absorption of nutrients by seeds, maintain the vitality of seeds, thereby improving the germination rate and germination potential of seeds, enhancing the disease resistance and stress resistance of crops, and ultimately achieving the purpose of improving crop yield and quality. Summary of the Invention

[0003] (1) Technical Problems to be Solved

[0004] The purpose of the present invention is to provide a seed soaking solution and a preparation method thereof, so as to improve the absorption efficiency of seeds for nutrients, optimize the formula by using natural active substances such as seaweed extracts and introduce nanotechnology to improve the utilization rate and biological activity of the effective components of the seed soaking solution, promote the absorption of nutrients by seeds, maintain the vitality of seeds, thereby improving the germination rate and germination potential of seeds, enhancing the disease resistance and stress resistance of crops, and ultimately achieving the purpose of improving crop yield and quality.

[0005] (2) Technical Solutions

[0006] To achieve the above purpose, on the one hand, the present invention provides a seed soaking solution, which is composed of the following raw materials in parts by weight: 2 - 6 parts of modified nano zinc oxide, 1 - 2 parts of hydrogen peroxide, 2 - 8 parts of ascorbic acid, 5 - 10 parts of seaweed extract, 1 - 5 parts of potassium dihydrogen phosphate, 1 - 5 parts of proline, 1 - 5 parts of polysorbate - 20, 2 - 4 parts of polyethylene glycol, and 30 - 50 parts of purified water.

[0007] Furthermore, the seed soaking solution further includes:

[0008] Polyacrylate-metal composite material;

[0009] The weight ratio of the polyacrylate-metal composite material to the modified nano-zinc oxide is 2:(2 - 6);

[0010] The specific surface area of the polyacrylate-metal composite material is 400 - 500 m 2 / g and the nano size is 60 - 80 nm.

[0011] Furthermore, the preparation method of the polyacrylate-metal composite material includes:

[0012] S11. Add purified water into a container and sequentially add calcium chloride, magnesium chloride, ferric chloride and copper sulfate under stirring. The stirring temperature is 50 - 60 °C, and stir for 1 - 2 h until fully dissolved to obtain a mixed metal ion solution;

[0013] S12. Dissolve polyacrylic acid in purified water under stirring for 1 - 2 h. After fully dissolving, adjust the pH value to 7.0 - 7.5 with sodium hydroxide solution to obtain a polyacrylic acid solution;

[0014] S13. At room temperature, slowly add the polyacrylic acid solution to the stirring mixed metal ion solution. The stirring speed is 500 - 600 rpm / min, and stir for 2 - 4 h to obtain a first mixed solution;

[0015] S14. Add N,N-methylenebisacrylamide to the first mixed solution and continue stirring for 1 - 2 h, then raise the temperature to 60 - 80 °C. Add ammonium persulfate under nitrogen protection, and the reaction time is 6 - 8 h. Cool the reaction product to room temperature to obtain a second mixed solution;

[0016] S15. Centrifuge the second mixed solution at a high speed. The centrifugation speed is 5000 - 8000 rpm / min, and centrifuge for 15 - 20 min. Wash the separated solid with purified water 5 times and then place it in a vacuum drying oven for drying. The drying temperature is 50 - 60 °C, and the drying time is 24 - 30 h. Then obtain the polyacrylate-metal composite material and grind it into a powder for standby.

[0017] Furthermore, the concentration of the mixed metal ion solution is 1 - 1.5 mol / L.

[0018] Furthermore, the preparation method of the modified nano-zinc oxide includes:

[0019] S21. Take an appropriate amount of zinc acetate solid and dissolve it in absolute ethanol with stirring at a temperature of 50 - 60 °C. After stirring for 1 - 2 h, a zinc acetate solution is obtained.

[0020] S22. While stirring, add the sodium hydroxide solution dropwise to the zinc acetate solution at a temperature of 50 - 60 °C. After stirring for 2 - 4 h, add a surfactant, then raise the temperature to 70 - 80 °C and stir for 4 - 5 h to obtain a third mixed solution.

[0021] S23. Let the third mixed solution stand for 3 - 4 h and then perform solid - liquid separation. The separated solid is washed 5 times with absolute ethanol and then placed in a vacuum drying oven for drying at a temperature of 60 - 80 °C for 12 - 18 h to obtain a white solid.

[0022] S24. Place the white solid in a muffle furnace for roasting with a heating rate of 2 - 5 °C / min, a roasting temperature of 400 - 450 °C, and a roasting time of 4 - 5 h to obtain nano - zinc oxide, which is then ground into a powder to obtain nano - zinc oxide powder.

[0023] S25. Under nitrogen protection, add the nano - zinc oxide powder and 3 - aminopropyltriethoxysilane to absolute ethanol in sequence and reflux with stirring for 8 - 10 h at a temperature of 70 - 80 °C. Cool the reaction product to room temperature to obtain a fourth mixed solution.

[0024] S26. Let the fourth mixed solution stand for 3 - 4 h and then perform solid - liquid separation. The separated solid is washed 5 times with absolute ethanol and then placed in a vacuum drying oven for drying at a temperature of 60 - 80 °C for 12 - 18 h to obtain modified nano - zinc oxide, which is then ground into a powder for standby.

[0025] Furthermore, the particle size of the modified nano - zinc oxide is 20 - 40 nm, the specific surface area is 100 - 120 m 2 / g and the surface of the modified nano - zinc oxide contains amino groups (-NH2).

[0026] Furthermore, the mass ratio of the surfactant to the modified nano - zinc oxide is 8:(2 - 6).

[0027] Furthermore, the surfactant is one or more of cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate (SDBS), sodium lauryl sulfate (SLS), and sodium dodecyl sulfate (SDS).

[0028] On the other hand, based on the same inventive concept, the present invention also provides a preparation method of a seed soaking solution, which is applied to the described seed soaking solution and includes the following steps:

[0029] S31. Add purified water into a container, and add polysorbate-20 and polyethylene glycol into the purified water under stirring. The stirring temperature is 50-60°C, and stir for 2-3 hours until completely dissolved to obtain a fifth mixed solution;

[0030] S32. Add polyacrylate-metal composite material and modified nano-zinc oxide into the fifth mixed solution under stirring. After stirring for 2-3 hours, add absolute ethanol for ultrasonic treatment. The ultrasonic frequency is 40-50 kHz, the ultrasonic temperature is 50-60°C, and after ultrasonic treatment for 2-4 hours, a sixth mixed solution is obtained;

[0031] S33. Add hydrogen peroxide, ascorbic acid, seaweed extract, potassium dihydrogen phosphate and proline into the fifth mixed solution in sequence under stirring, and heat in a water bath at the same time. The heating temperature is 60-80°C, the heating time is 4-5 hours, and stir for 3-4 hours until completely dissolved, and adjust the pH value to 6.5-7.0 with sodium hydroxide solution to obtain the seed soaking solution.

[0032] Furthermore, the usage method of the seed soaking solution is as follows: Mix the seed soaking solution and clear water according to a mass ratio of 1:(10-15) and stir evenly. Immerse the seeds completely in the mixed solution, take out the seeds after soaking for 12-15 hours, and rinse with clear water to remove the residual soaking solution on the surface of the seeds. Then, according to actual needs, directly sow or carry out germination treatment.

[0033] The action mechanisms of the above raw material components are as follows:

[0034] Seaweed extract is a natural bioactive substance extracted from seaweeds (such as brown algae, red algae, and green algae, etc.). The main components include polysaccharides (such as alginate, fucoidan, etc.), amino acids (such as glutamic acid, glycine, etc.), vitamins (such as vitamin C, vitamin E, etc.), minerals (such as potassium, calcium, magnesium, iron, zinc, etc.) and phytohormones (such as cytokinin, auxin, gibberellin, etc.). It is widely used in agriculture as a biostimulant to promote plant growth and improve stress resistance. In the seed soaking solution, the phytohormones in the seaweed extract can stimulate the growth of the seed embryo, promote seed germination and root development; rich in osmotic adjustment substances such as betaine, which can improve the drought, cold and salt tolerance of seeds; rich in various trace elements and amino acids can provide necessary nutrients for seed germination; at the same time, the polysaccharide component can activate the immune system of seeds and improve disease resistance.

[0035] Potassium dihydrogen phosphate (KH2PO4) is an inorganic compound that is highly soluble in water and weakly acidic. It is commonly used as an efficient phosphorus and potassium fertilizer in agricultural production to promote crop growth. In the seed soaking solution, potassium dihydrogen phosphate can provide two important nutrient elements, potassium (K) and phosphorus (P), for seed germination and early growth. Phosphorus is an important component of energy molecules such as ATP and helps with energy metabolism during seed germination. Phosphorus can also promote the growth of crop roots and contribute to the formation of strong roots in seedlings. Potassium can enhance the stress resistance of plants, such as drought resistance, cold resistance, and disease resistance. At the same time, as a soluble salt, potassium dihydrogen phosphate also helps to regulate the osmotic pressure between the seeds and the external environment, thereby promoting the absorption of water by the seeds.

[0036] Proline (C5H9NO2) is a non-essential amino acid with a unique cyclic structure. During agricultural production, proline often plays an important role as an osmotic regulator and protectant. Under adverse conditions, the proline content in crops will increase significantly. In the seed soaking solution, proline can help maintain the osmotic balance within cells, interact with cell membrane phospholipids, enhance membrane stability, promote the absorption of nutrients by seeds, and facilitate seed germination and seedling growth.

[0037] Polysorbate-20 is a non-ionic surfactant formed by esterifying sorbitol with fatty acids and then adding ethylene oxide. In the seed soaking solution, polysorbate-20 can reduce the surface tension of water, increase permeability, enabling the nutrients in the soaking solution to better penetrate into the seeds. At the same time, it helps other active ingredients to be evenly dispersed in the soaking solution, improving bioavailability. It can also clean the impurities on the seed surface and promote the absorption of other nutrient components by the seeds.

[0038] Polyethylene glycol (PEG) is a water-soluble polymer compound formed by polymerizing ethylene glycol. It has good water retention and biocompatibility and is widely used in the fields of agriculture and medicine. In the seed soaking solution, the water retention effect of polyethylene glycol can adsorb water, slow down water evaporation, extend the effective action time of the soaking solution. At the same time, it can regulate the osmotic potential of the soaking solution, simulate drought stress, thereby enhancing the drought resistance of seeds. It can also form a protective film on the seed surface to reduce water loss from the seeds.

[0039] Nano zinc oxide (ZnO) is a zinc oxide material with a nanoscale particle size. Due to its small particle size and high specific surface area, nano zinc oxide is widely used in multiple fields. Modified nano zinc oxide with a particle size of 20 - 40 nm and containing amino groups (-NH2) on the surface is prepared by the sol - gel method combined with surface modification. Compared with ordinary zinc oxide, the modified nano zinc oxide has a smaller particle size, a larger specific surface area, better dispersibility and stability, and at the same time has excellent antibacterial and antiviral activities, and can inhibit the growth of a variety of bacteria and fungi. In the seed soaking solution, the modified nano zinc oxide has a broad - spectrum antibacterial effect, which can protect seeds from pathogenic microorganisms. At the same time, zinc is an essential trace element for crops and nano - scale zinc oxide is more easily absorbed and utilized. Zinc also participates in the synthesis of plant hormones (such as auxin). The introduction of surface amino groups (-NH2) helps the transport of nutrients, promotes seed germination and seedling growth, and also helps to improve the antioxidant capacity and stress resistance of seeds.

[0040] Hydrogen peroxide (H2O2) is a strong oxidant and can be decomposed into water and oxygen under appropriate conditions. In the seed soaking solution, low - concentration H2O2 can break seed dormancy, stimulate seed germination, and the decomposed oxygen can promote the respiration of seeds, increase energy supply, and indirectly promote seeds to absorb nutrients. However, higher - concentration H2O2 will have an oxidative toxic effect on seeds, so it is generally used in combination with antioxidants. Antioxidants protect seeds from oxidative damage, create a fine - balanced redox environment for seeds, can minimize damage to seeds, break the dormancy state of seeds, and then activate relevant enzymes in seeds.

[0041] Ascorbic acid (C6H8O6) is a water - soluble vitamin with strong antioxidant properties and plays important physiological functions in both humans and plants. During the growth and development of crops, ascorbic acid participates in various physiological processes such as photosynthesis and cell division. In the seed soaking solution, ascorbic acid can scavenge free radicals, protect seed cells from oxidative damage, participate in the synthesis of cell walls, promote cell division and elongation, improve the resistance of seeds to environmental stress, enhance stress resistance, and at the same time promote the absorption of nutrients such as Fe and contribute to the synthesis of chlorophyll.

[0042] Polyacrylate is a polymer material formed by the polymerization of polyacrylate polymer chains, which has good film - forming properties and adhesiveness, and at the same time has a relatively high specific surface area and small nano - size. Introducing metal ions such as Ca 2+ 、Mg 2+ 、Fe 3+ 、Cu 2+ etc. on the surface of the polyacrylate polymer to form a polyacrylate - metal composite material. The polymer network structure of polyacrylate promotes the slow release of Ca 2+, Mg 2+ , Fe 3+ , Cu 2+ and other metal ions, Ca 2+ and Mg 2+ are macronutrients essential for plant growth. Fe 3+ and Cu 2+ are essential micronutrients, thereby providing a continuous supply of mineral element nutrition for seeds and promoting the growth and development of seeds. At the same time, the film-forming property of polyacrylate plays a certain protective role for seeds, which can firmly coat the heavy metals harmful to seeds and humans, and through ion exchange, release Ca 2+ , Mg 2+ , Fe 3+ , Cu 2+ and other beneficial mineral elements, reducing the influence of adverse factors.

[0043] In the seed soaking solution, the polyacrylate-metal composite material, modified nano-zinc oxide, hydrogen peroxide and ascorbic acid act through a synergistic effect. The polyacrylate-metal composite material can effectively adsorb various nutritional components such as polysaccharides, amino acids, vitamins and plant hormones in the seed soaking solution due to its unique network structure. Its large specific surface area and rich pore structure can effectively prevent the agglomeration of modified nano-zinc oxide, helping to improve the biological activity and catalytic activity of modified nano-zinc oxide. Modified nano-zinc oxide catalyzes and converts the nutritional components attached to the polyacrylate-metal composite material into a state more easily absorbed by seeds, and the resulting nutritional components after conversion are directly captured by modified nano-zinc oxide through physical adsorption and chemical action. Hydrogen peroxide softens the seed coat and promotes the relaxation of the cell wall to open the internal channels of the seeds. The modified nano-zinc oxide carrying the nutritional components enters the seeds through electrostatic adsorption, coordination and its own nano-size effect at the channels, and at the same time generates reactive oxygen species (ROS) and Zn 2+It affects the activity of transcription factors and directly acts on the DNA of seeds, activates the enzymes inside the seeds, increases the metabolic rate of seeds, ends the dormant state of seeds, and the modified nano-zinc oxide carries nutrient components into the seeds to directly enhance the absorption of nutrient components by seeds. An appropriate concentration of reactive oxygen species can promote seed germination, but the presence of excessive reactive oxygen species in the system will be toxic to seeds. Both hydrogen peroxide and modified nano-zinc oxide will generate a large number of reactive oxygen species, resulting in a high concentration of reactive oxygen species in the system, which is unfavorable for the survival environment of seeds. By adding ascorbic acid, excessive reactive oxygen species can be scavenged and reduced to water and other harmless substances, avoiding oxidative damage to seeds caused by too high a concentration of reactive oxygen species. At the same time, ascorbic acid further promotes the opening of internal channels in seeds by participating in cell wall degradation, participates in the cell division process to further increase the metabolic rate of seeds, and ascorbic acid can also act as an electron donor to maintain the catalytic activity of modified nano-zinc oxide, thus promoting the continuous conversion of modified nano-zinc oxide to nutrients. In addition, the heavy metals contained in the seeds themselves will also hinder the absorption of nutrient elements by seeds. Ascorbic acid forms heavy metal-ascorbic acid chelates by chelating with heavy metals in the seeds, thereby reducing the heavy metal content of the seeds themselves. The polyacrylate-metal composite effectively interacts with these heavy metal-ascorbic acid chelates through physical adsorption and chemical action to effectively fix heavy metals and prevent them from being absorbed by seeds again, while releasing Ca 2+ , Mg 2+ , Fe 3+ , Cu 2+ and other mineral elements necessary for seed growth and development, thereby improving the absorption of mineral elements by seeds. In short, the polyacrylate-metal composite, modified nano-zinc oxide, hydrogen peroxide and ascorbic acid can indeed provide a suitable biological environment for seeds to germinate and absorb nutrients through their synergistic effects, while improving the absorption efficiency of seeds for nutrients, maintaining the vitality of seeds, and then increasing the germination rate and germination potential of seeds, enhancing the disease resistance and stress resistance of crops, and ultimately achieving the purpose of increasing crop yield and quality.

[0044] (3) Beneficial effects

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] 1. In the seed soaking solution, the polyacrylate-metal composite, modified nano-zinc oxide, hydrogen peroxide and ascorbic acid act through their synergistic effects. The polyacrylate-metal composite acts as a carrier to effectively adsorb various nutrient components and prevent the agglomeration of modified nano-zinc oxide, which helps to improve the biological activity and catalytic activity of modified nano-zinc oxide;

[0047] 2. The modified nano-zinc oxide catalyzes the conversion of the nutrient components attached to the polyacrylate-metal composite material into a state that is more easily absorbed by the seeds, and the resulting nutrient components after conversion are directly captured by the modified nano-zinc oxide through physical adsorption and chemical action;

[0048] 3. Hydrogen peroxide opens the internal channels of the seeds, and the modified nano-zinc oxide carrying the nutrient components enters the seeds. At the same time, reactive oxygen species (ROS) and Zn are produced 2+ which affect the activity of transcription factors and directly act on the DNA of the seeds, activate the enzymes inside the seeds, increase the seed metabolic rate, end the seed dormancy state, and directly enhance the absorption of nutrient components by the seeds;

[0049] 4. Ascorbic acid scavenges the excessive reactive oxygen species produced by hydrogen peroxide and the modified nano-zinc oxide. At the same time, it participates in the degradation of the cell wall to further promote the opening of the internal channels of the seeds, participates in the cell division process to further increase the metabolic rate of the seeds, and acts as an electron donor to maintain the catalytic activity of the modified nano-zinc oxide, thus promoting the continuous conversion of nutrients by the modified nano-zinc oxide;

[0050] 5. Ascorbic acid forms heavy metal-ascorbic acid chelates with heavy metals in the seeds to reduce the heavy metal content of the seeds. The polyacrylate-metal composite material interacts with these heavy metal-ascorbic acid chelates through physical adsorption and chemical action to effectively fix the heavy metals, and at the same time releases Ca 2+ 、Mg 2+ 、Fe 3+ 、Cu 2+ and other mineral elements necessary for the growth and development of the seeds, and improves the absorption of mineral elements by the seeds. Brief Description of the Drawings

[0051] Figure 1 This is the SEM image of the polyacrylate-metal composite material in Example 1 of the present invention;

[0052] Figure 2 This is the SEM image of the modified nano-zinc oxide in Example 1 of the present invention;

[0053] Figure 3 This is the XRD image of the modified nano-zinc oxide in Example 1 of the present invention. Detailed Embodiments

[0054] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present invention.

[0055] The test equipment and preparations for the following embodiments are as follows: electronic balance (Sartorius, Germany), pH meter (Fengrui, Tangshan), electrothermal constant temperature water bath (Kedao, Jiangsu), electrothermal blast drying oven (Gerida, Suzhou), vacuum drying oven (Jiecheng, Shanghai), high-speed grinder (Tianfang Machinery, Shandong), magnetic stirrer (Meiyingpu, Shanghai), high-speed centrifuge (Jidi, Guangzhou), muffle furnace (Kruida, Shandong), high-speed disperser (Ruitong, Sichuan), rotary evaporator (Yaote, Shanghai), scanning electron microscope (Zeiss, Germany), specific surface area analyzer (Beishide, Beijing), low-temperature constant temperature incubator (Hetian, Shanghai), inductively coupled plasma atomic emission spectrometry (Thermo Fisher, USA); bentonite was purchased from Sichuan Hexinrunda Mining Co., Ltd., and chemical drugs and reagents were purchased from Sigma-Aldrich Co., Ltd.

[0056] Example 1

[0057] This example discloses a seed soaking solution, which is composed of the following raw materials in parts by weight: 4 parts of modified nano-zinc oxide, 1 part of hydrogen peroxide, 5 parts of ascorbic acid, 8 parts of seaweed extract, 3 parts of potassium dihydrogen phosphate, 4 parts of proline, 3 parts of polysorbate-20, 3 parts of polyethylene glycol, and 40 parts of purified water. The seed soaking solution also includes a polyacrylate-metal composite material. The weight ratio of the polyacrylate-metal composite material to the modified nano-zinc oxide is 2:4. The specific surface area of the polyacrylate-metal composite material is 400-500m 2 / g and the nano size is 60-80nm.

[0058] In the seed soaking solution, the polyacrylate-metal composite material, modified nano-zinc oxide, hydrogen peroxide, and ascorbic acid act through a synergistic effect. As Figure 1 shown, the polyacrylate-metal composite material has a large specific surface area and a rich pore structure, with a specific surface area as high as 400-500m 2 / g. At the same time, it also has a unique network structure that can be used as a carrier to effectively adsorb various nutrient components such as polysaccharides, amino acids, vitamins, and plant hormones in the seed soaking solution. Its large specific surface area and rich pore structure can effectively prevent the agglomeration of modified nano-zinc oxide. As Figure 2 shown, the particle size of the modified nano-zinc oxide is uniform, the morphology is spherical, the nano size is 20-40nm, but obvious agglomeration phenomenon is shown. The polyacrylate-metal composite material can provide dispersion sites for the modified nano-zinc oxide to prevent the agglomeration of the modified nano-zinc oxide, and the anionic groups (-COO-) on the surface of the polyacrylate are opposite to the positive charges (-NH3 +) The electrostatic repulsion between them also effectively prevents the mutual attraction and aggregation of modified nano-zinc oxide particles, which helps to improve the biological activity and catalytic activity of modified nano-zinc oxide. The modified nano-zinc oxide will attach to the nutrient components of the polyacrylate-metal composite and catalytically convert them into a state that is more easily absorbed by seeds. From Figure 3 From the XRD pattern of the modified nano-zinc oxide, it can be clearly seen that the (100), (002), and (101) crystal planes of the modified nano-zinc oxide exhibit relatively high characteristic diffraction peak intensities. Therefore, the modified nano-zinc oxide has an obvious crystal structure and can promote the conversion of nutrient elements (such as amino acids, vitamins, mineral elements, and inorganic elements, etc.) through catalytic action. The zinc ions in the nano-zinc oxide are the main catalytic active centers, which can catalyze the decarboxylation reaction of amino acids to generate simpler small-molecule amino acids and corresponding amines, catalyze the conversion of fat-soluble vitamins into water-soluble vitamins, and at the same time promote the dissolution and conversion of mineral elements. Moreover, the obtained nutrient components after conversion are directly captured by the modified nano-zinc oxide through physical adsorption and chemical interactions. The relatively large specific surface area of the modified nano-zinc oxide can provide adsorption sites for the converted nutrient components. At the same time, the amino group (-NH2) on the surface of the modified nano-zinc oxide forms an ester bond (-COO-) with the carboxyl group (-COOH) on the surface of the converted amino acid, and forms coordination compounds with mineral elements such as Ca 2+ 、Mg 2+ 、Fe 3+ and Cu 2+ etc., and forms intermolecular hydrogen bonds and other chemical interactions with polar groups such as hydroxyl (-OH) and carbonyl (-C=O-) on the surface of vitamins and polysaccharides, and is thus captured by the modified nano-zinc oxide. Hydrogen peroxide softens the seed coat and promotes the relaxation of the cell wall to open the internal channels of the seeds. Hydrogen peroxide is a strong oxidant that can directly oxidize the structural proteins on the surface of the seed coat, oxidize the sulfhydryl group (-SH) in the structural proteins to form a disulfide bond (-S-S-), change the tertiary structure of the protein, oxidize the amide group (-CO-NH2) to form a carboxyl group (-COOH) and ammonia (NH3), break the peptide bonds of the protein, and make the originally closely arranged protein network become loose. At the same time, the hydroxyl group (-CH2OH) and glycosidic bond (-O-) in the polysaccharides on the surface of the seed coat are also oxidized and broken under the action of hydrogen peroxide. After the structural proteins in the cell wall are oxidized, the cross-linking with other cell wall components will decrease. Hydrogen peroxide will continue to activate the peroxidase in the cell wall, further catalyze the oxidation of cell wall components, and promote the relaxation of the cell wall, thereby opening the internal channels of the seeds. The modified nano-zinc oxide carrying the nutrient components enters the seed interior through electrostatic adsorption, coordination, and its own nano-size effect at the channels. The modified nano-zinc oxide carries a positive charge and is easy to combine with the negatively charged cell membrane. At the same time, the Zn 2+It will form coordination bonds through coordination with amino acid residues such as carboxyl (-COOH), phosphate (-PO4H2), amino (-NH2), and sulfhydryl (-SH) in proteins. Moreover, the relatively small nano-size of the modified nano-zinc oxide can directly penetrate the cell membrane and enter the interior of the cell. These combined effects enable the modified nano-zinc oxide carrying nutrient components to enter the interior of the seeds. Meanwhile, the reactive oxygen species (ROS) jointly generated by hydrogen peroxide and the modified nano-zinc oxide and the Zn generated by the modified nano-zinc oxide 2+ directly affect the activity of transcription factors and directly act on the DNA of the seeds. As a signal molecule, reactive oxygen species activate specific signal transcription molecules, triggering the activation of transcription factors such as WRKY, MYB, NAC, and BZIP, regulating gene expression, and Zn 2+ as a cofactor for many enzymes directly affects the transcriptional activity of transcription factors, binds to DNA and participates in the DNA replication and repair processes. At the same time, it promotes the synthesis of gibberellin, regulates cell division and growth, ends the seed dormancy state, activates hydrolases, antioxidant enzymes, and protein kinases inside the seeds, improves the seed metabolic rate, and thus enhances the absorption of nutrients by the seeds. Moreover, the modified nano-zinc oxide carrying nutrient components entering the interior of the seeds directly enhances the absorption of nutrient components by the seeds. An appropriate concentration of reactive oxygen species can promote seed germination, but the presence of excessive reactive oxygen species in the system will be toxic to the seeds. Excessive reactive oxygen species will undergo oxidative polymerization with phenolic substances on the seed coat surface, making the seed coat hard and affecting the absorption of nutrients, causing the seeds to lose vitality and die. Both hydrogen peroxide and the modified nano-zinc oxide will generate a large amount of reactive oxygen species, resulting in a relatively high concentration of reactive oxygen species in the system, which is unfavorable for the survival environment of the seeds. By adding ascorbic acid, excessive reactive oxygen species can be scavenged and reduced to water and other harmless substances, avoiding oxidative damage to the seeds caused by too high a concentration of reactive oxygen species. At the same time, ascorbic acid also further promotes the opening of internal channels in the seeds by participating in cell wall degradation, participates in the cell division process to further improve the seed metabolic rate, and ascorbic acid can also act as an electron donor to provide electrons for the modified nano-zinc oxide to reduce the surface of the modified nano-zinc oxide, regulate the redox potential on its surface, and thus maintain the catalytic activity of the modified nano-zinc oxide to promote the continuous conversion of nutrient substances by the modified nano-zinc oxide. In addition, heavy metals contained in the seeds themselves will also hinder the absorption of nutrient elements by the seeds. Heavy metal ions will interfere with the ion channels on the cell membrane, resulting in Ca 2+ 、K + 、Mg 2+The absorption of essential elements such as [element names] is blocked, while the enzyme activity is inhibited, delaying seed germination. Ascorbic acid forms heavy metal - ascorbic acid chelates by chelating with heavy metals such as cadmium, lead, chromium, mercury, and arsenic in the seeds, thereby reducing the heavy metal content in the seeds themselves and preventing the presence of heavy metals from hindering the absorption of nutrients by the seeds. The polyacrylate - metal composite interacts with these heavy metal - ascorbic acid chelates through physical adsorption and chemical action to effectively fix the heavy metals and prevent them from being absorbed by the seeds again. The polyacrylate - metal composite has excellent adsorption performance and can firmly adsorb the heavy metal - ascorbic acid chelates onto the surface of the porous structure. At the same time, it undergoes ion exchange with the heavy metal ions in the heavy metal - ascorbic acid chelates to further fix the heavy metal ions and provide a physical barrier to prevent the direct contact between the heavy metals and the seeds, while releasing Ca 2+ , Mg 2+ , Fe 3+ , Cu 2+ and other mineral elements essential for seed growth and development, improving the absorption of mineral elements by the seeds. In summary, the polyacrylate - metal composite, modified nano - zinc oxide, hydrogen peroxide, and ascorbic acid can indeed provide a suitable biological environment for the seeds to absorb nutrients through their synergistic effect, while improving the absorption efficiency of the seeds for nutrients, maintaining the vitality of the seeds, thereby increasing the germination rate and germination potential of the seeds, enhancing the disease resistance and stress resistance of the crops, and ultimately achieving the goal of increasing the yield and quality of the crops.

[0059] The preparation method of the polyacrylate - metal composite includes:

[0060] S11. Add purified water to a container and sequentially add calcium chloride, magnesium chloride, iron chloride, and copper sulfate under stirring. The stirring temperature is 50 - 60 °C, and stir for 1 - 2 h until fully dissolved to obtain a mixed metal ion solution;

[0061] S12. Dissolve polyacrylic acid in purified water under stirring for 1 - 2 h. After fully dissolving, adjust the pH value to 7.0 - 7.5 with sodium hydroxide solution to obtain a polyacrylic acid solution;

[0062] S13. At room temperature, slowly add the polyacrylic acid solution to the stirring mixed metal ion solution at a stirring speed of 500 - 600 rpm / min, and stir for 2 - 4 h to obtain a first mixed solution;

[0063] S14. Add N,N - methylenebisacrylamide to the first mixed solution and continue stirring for 1 - 2 h, then raise the temperature to 60 - 80 °C. Add ammonium persulfate under nitrogen protection, and react for 6 - 8 h. Cool the reaction product to room temperature to obtain a second mixed solution;

[0064] S15. Centrifuge the second mixed solution at a high speed with a centrifuge speed of 5000 - 8000 rpm / min for 15 - 20 min. Wash the separated solid 5 times with purified water and then place it in a vacuum drying oven for drying. The drying temperature is 50 - 60 °C and the drying time is 24 - 30 h, thus obtaining the polyacrylate-metal composite material, which is ground into a powder form and reserved for use.

[0065] The concentration of the mixed metal ion solution is 1 - 1.5 mol / L.

[0066] The preparation method of the modified nano-zinc oxide includes:

[0067] S21. Take an appropriate amount of zinc acetate solid and dissolve it in absolute ethanol with stirring at a temperature of 50 - 60 °C for 1 - 2 h to obtain a zinc acetate solution;

[0068] S22. While stirring, drop the sodium hydroxide solution into the zinc acetate solution. Stir at a temperature of 50 - 60 °C for 2 - 4 h, then add a surfactant, raise the temperature to 70 - 80 °C, and stir for 4 - 5 h to obtain a third mixed solution;

[0069] S23. Let the third mixed solution stand for 3 - 4 h and then separate the solid from the liquid. Wash the separated solid 5 times with absolute ethanol and then place it in a vacuum drying oven for drying. The drying temperature is 60 - 80 °C and the drying time is 12 - 18 h to obtain a white solid;

[0070] S24. Place the white solid in a muffle furnace for roasting. The heating rate is 2 - 5 °C / min, the roasting temperature is 400 - 450 °C, and the roasting time is 4 - 5 h, thus obtaining nano-zinc oxide and grinding it into a powder form to obtain nano-zinc oxide powder;

[0071] S25. Under nitrogen protection, successively add the nano-zinc oxide powder and 3-aminopropyltriethoxysilane to absolute ethanol and reflux with stirring for 8 - 10 h. The stirring temperature is 70 - 80 °C, and cool the reaction product to room temperature to obtain a fourth mixed solution;

[0072] S26. Let the fourth mixed solution stand for 3 - 4 h and then separate the solid from the liquid. Wash the separated solid 5 times with absolute ethanol and then place it in a vacuum drying oven for drying. The drying temperature is 60 - 80 °C and the drying time is 12 - 18 h, thus obtaining the modified nano-zinc oxide and grinding it into a powder form for reserve.

[0073] The particle size of the modified nano-zinc oxide is 20 - 40 nm, the specific surface area is 100 - 120 m 2 / g and the surface of the modified nano-zinc oxide contains amino groups (-NH2).

[0074] The mass ratio of the surfactant to the modified nano-zinc oxide is 8:(2 - 6).

[0075] The surfactant is one or more of cetyltrimethylammonium bromide (CTAB), sodium dodecylbenzenesulfonate (SDBS), sodium lauryl sulfate (SLS), and sodium dodecyl sulfate (SDS).

[0076] On the other hand, based on the same inventive concept, the present invention also provides a method for preparing a seed soaking solution, which is applied to the described seed soaking solution and includes the following steps:

[0077] S31. Add purified water into a container, and add polysorbate-20 and polyethylene glycol into the purified water under stirring. The stirring temperature is 50-60 °C, and stir for 2-3 h until completely dissolved to obtain a fifth mixed solution;

[0078] S32. Add the polyacrylate-metal composite material and modified nano-zinc oxide into the fifth mixed solution under stirring. After stirring for 2-3 h, add anhydrous ethanol for ultrasonic treatment. The ultrasonic frequency is 40-50 kHz, the ultrasonic temperature is 50-60 °C, and after ultrasonic treatment for 2-4 h, a sixth mixed solution is obtained;

[0079] S33. Add hydrogen peroxide, ascorbic acid, seaweed extract, potassium dihydrogen phosphate, and proline into the fifth mixed solution in sequence under stirring, and at the same time, heat in a water bath. The heating temperature is 60-80 °C, the heating time is 4-5 h, and stir for 3-4 h until completely dissolved. Then adjust the pH value to 6.5-7.0 with sodium hydroxide solution to obtain the seed soaking solution.

[0080] The usage method of the described seed soaking solution is as follows: Mix the seed soaking solution and clear water according to a mass ratio of 1:(10-15) and stir evenly. Completely immerse the seeds in the mixed solution. After soaking for 12-15 h, take out the seeds and rinse them with clear water to remove the residual soaking solution on the surface of the seeds. Then, according to actual needs, directly carry out sowing or germination promotion treatment.

[0081] Example 2

[0082] This example discloses a seed soaking solution, which is composed of the following raw materials in parts by weight: 2 parts of modified nano-zinc oxide, 2 parts of hydrogen peroxide, 2 parts of ascorbic acid, 5 parts of seaweed extract, 1 part of potassium dihydrogen phosphate, 1 part of proline, 1 part of polysorbate-20, 2 parts of polyethylene glycol, and 30 parts of purified water. The seed soaking solution also includes a polyacrylate-metal composite material. The weight ratio of the polyacrylate-metal composite material to the modified nano-zinc oxide is 2:2. The specific surface area of the polyacrylate-metal composite material is 800-1000 m 2 / g and the nano size is 60-80 nm.

[0083] The preparation method of the polyacrylate-metal composite material and the modified nano-zinc oxide in this example is the same as that in Example 1. The preparation method of a seed soaking solution in this example is the same as that in Example 1.

[0084] Example 3

[0085] This example discloses a seed soaking solution, which is composed of the following raw materials in parts by weight: 6 parts of modified nano-zinc oxide, 1 part of hydrogen peroxide, 8 parts of ascorbic acid, 10 parts of seaweed extract, 5 parts of potassium dihydrogen phosphate, 5 parts of proline, 5 parts of polysorbate-20, 4 parts of polyethylene glycol, and 50 parts of purified water. The seed soaking solution also includes a polyacrylate-metal composite material. The weight ratio of the polyacrylate-metal composite material to the modified nano-zinc oxide is 2:6. The specific surface area of the polyacrylate-metal composite material is 800-1000 m 2 / g and the nano size is 60-80 nm.

[0086] The preparation method of the polyacrylate-metal composite material and the modified nano-zinc oxide in this example is the same as that in Example 1. The preparation method of a seed soaking solution in this example is the same as that in Example 1.

[0087] Example 4

[0088] This example discloses a seed soaking solution, which is composed of the following raw materials in parts by weight: 4 parts of modified nano-zinc oxide, 1 part of hydrogen peroxide, 8 parts of ascorbic acid, 10 parts of seaweed extract, 5 parts of potassium dihydrogen phosphate, 5 parts of proline, 5 parts of polysorbate-20, 4 parts of polyethylene glycol, and 50 parts of purified water. The seed soaking solution also includes a polyacrylate-metal composite material. The weight ratio of the polyacrylate-metal composite material to the modified nano-zinc oxide is 2:6. The specific surface area of the polyacrylate-metal composite material is 800-1000 m 2 / g and the nano size is 60-80 nm.

[0089] The preparation method of the polyacrylate-metal composite material and the modified nano-zinc oxide in this example is the same as that in Example 1. The preparation method of a seed soaking solution in this example is the same as that in Example 1.

[0090] Control Group 1

[0091] The difference between this example and Example 1 is that it does not contain a polyacrylate-metal composite material.

[0092] This example discloses a seed soaking solution, which is composed of the following raw materials in parts by weight: 4 parts of modified nano-zinc oxide, 1 part of hydrogen peroxide, 5 parts of ascorbic acid, 8 parts of seaweed extract, 3 parts of potassium dihydrogen phosphate, 4 parts of proline, 3 parts of polysorbate-20, 3 parts of polyethylene glycol, and 40 parts of purified water.

[0093] The preparation method of the modified nano-zinc oxide in this example is the same as that in Example 1. The preparation method of a seed soaking solution in this example is the same as that in Example 1.

[0094] Control Group 2

[0095] The difference between this example and Example 1 is that it does not contain modified nano-zinc oxide.

[0096] This example discloses a seed soaking solution, which is composed of the following raw materials in parts by weight: 1 part of hydrogen peroxide, 5 parts of ascorbic acid, 8 parts of seaweed extract, 3 parts of potassium dihydrogen phosphate, 4 parts of proline, 3 parts of polysorbate-20, 3 parts of polyethylene glycol, and 40 parts of purified water. The seed soaking solution also includes a polyacrylate-metal composite material, and the polyacrylate-metal composite material is 2 parts. The specific surface area of the polyacrylate-metal composite material is 400-500m 2 / g and the nano size is 60-80nm.

[0097] The preparation method of the polyacrylate-metal composite material in this example is the same as that in Example 1. The preparation method of a seed soaking solution in this example is the same as that in Example 1.

[0098] Control Group 3

[0099] The difference between this example and Example 1 is that it does not contain ascorbic acid.

[0100] This example discloses a seed soaking solution, which is composed of the following raw materials in parts by weight: 4 parts of modified nano-zinc oxide, 1 part of hydrogen peroxide, 8 parts of seaweed extract, 3 parts of potassium dihydrogen phosphate, 4 parts of proline, 3 parts of polysorbate-20, 3 parts of polyethylene glycol, and 40 parts of purified water. The seed soaking solution also includes a polyacrylate-metal composite material, and the weight ratio of the polyacrylate-metal composite material to the modified nano-zinc oxide is 2:4. The specific surface area of the polyacrylate-metal composite material is 400-500m 2 / g and the nano size is 60-80nm.

[0101] The preparation methods of the polyacrylate-metal composite material and the modified nano-zinc oxide in this example are the same as those in Example 1. The preparation method of a seed soaking solution in this example is the same as that in Example 1.

[0102] Control Group 4

[0103] The difference between this example and Example 1 is that it does not contain hydrogen peroxide.

[0104] This embodiment discloses a seed soaking solution, which is composed of the following raw materials in parts by weight: 4 parts of modified nano-zinc oxide, 5 parts of ascorbic acid, 8 parts of seaweed extract, 3 parts of potassium dihydrogen phosphate, 4 parts of proline, 3 parts of polysorbate-20, 3 parts of polyethylene glycol, and 40 parts of purified water. The seed soaking solution further includes a polyacrylate-metal composite material. The weight ratio of the polyacrylate-metal composite material to the modified nano-zinc oxide is 2:4. The specific surface area of the polyacrylate-metal composite material is 400-500 m 2 / g and the nano size is 60-80 nm.

[0105] The preparation method of the polyacrylate-metal composite material and the modified nano-zinc oxide in this embodiment is the same as that in Example 1. The preparation method of a seed soaking solution in this embodiment is the same as that in Example 1.

[0106] Effect evaluation: Rice seed germination experiment: Select 160 rice seeds of the same size and plumpness, divide them into 8 groups, with 20 seeds in each experimental group. Mix the seed soaking solutions prepared from each experimental group with water according to a mass ratio of 1:15 and stir evenly. Immerse the paddy seeds of each experimental group completely in the mixed solution. After soaking for 15 h, take out the paddy seeds and rinse them with water to remove the residual soaking solution. Place double-layer filter paper in a petri dish, add 10 ml of 0.15 mol / L NaCl solution, put the soaked paddy seeds of each experimental group into it respectively, and place them in an incubator at (26±2)°C for dark cultivation. During the cultivation period, supplement purified water regularly and quantitatively until 90% of the paddy seeds germinate. Statistically calculate the germination rate of the paddy seeds (germination rate = number of germinated seeds / total number of tested seeds × 100%), germination potential (measured 6 days after the start of the experiment, germination potential = number of germinated seeds after 6 days of cultivation / total number of tested seeds × 100%), germination index (germination index = ∑(number of germinated seeds / germination time)), and seedling vigor index (seedling vigor index = germination rate × total length of seedlings), and record them in Table 1.

[0107] Table 1 Statistics on the germination and growth of rice seeds in each experimental group

[0108] Group Germination rate (%) Germination potential (%) Germination index Seedling vigor index Example 1 99.5 66.0 10.2 8.76 Example 2 98.0 57.5 9.5 8.04 Example 3 99.0 60.5 9.2 8.26 Example 4 98.5 62.5 9.9 8.35 Control group 1 94.0 60.5 8.7 7.90 Control group 2 90.0 50.0 6.5 5.55 Control group 3 92.0 52.5 7.4 6.01 Control group 4 91.5 54.5 7.6 6.31

[0109] The comparison of the germination and growth of paddy seeds in each experimental group is shown in Table 1. During the experiment, the paddy seeds began to germinate on the 5th day, and more than 90% of the paddy seeds reached the germination state on the 10th day. As can be seen from Table 1, the highest germination rate of the paddy seeds in Example 1 was 99.5%, and the number of germinated seeds was the largest on the 6th day, that is, the germination potential was also the highest at 66.0%. At the same time, both the germination index and the seedling vigor index showed relatively high levels. By comparing the germination and growth of the paddy seeds in Example 1 with those in the experimental groups of Control Group 1, Control Group 2, Control Group 3, and Control Group 4, it can be found that the germination and growth of the paddy seeds in the experimental groups of Control Group 1, Control Group 2, Control Group 3, and Control Group 4 were not as good as those of the paddy seeds in Example 1. Polyacrylate-metal composite material and ascorbic acid were not added to Control Group 1 and Control Group 3 respectively, and the germination rate, germination potential, germination index, and seedling vigor index of the paddy seeds also decreased significantly. This shows that if the heavy metal content in the seeds is too high, it will have a toxic effect on the seeds, affecting the absorption of nutrients by the seeds. At the same time, the germination rate, germination potential, germination index, and seedling vigor index of the paddy seeds in Control Group 2 and Control Group 4 were also significantly lower than those of the paddy seeds in Example 1. This shows that when the two substances of modified nano-zinc oxide and hydrogen peroxide are added simultaneously when preparing the seed soaking solution, the obtained seed soaking solution can significantly promote the absorption of nutrients by the seeds, maintain the vitality of the seeds, thereby increasing the germination rate and germination potential of the seeds, and making the seedlings have higher vitality.

[0110] Heavy metal adsorption and degradation experiment: Select 160 paddy seeds obtained by planting in heavy metal-polluted soil, divide them into 8 groups, with 20 seeds in each experimental group. After the pretreatment of the paddy seeds, the inductively coupled plasma-optical emission spectrometry (ICP-OES) method was used to measure the contents of heavy metals such as cadmium (Cd), lead (Pb), mercury (Hg), and arsenic (As) in the paddy seeds, record the corresponding values and take the average; the seed soaking solutions prepared from each experimental group were respectively mixed with water according to a mass ratio of 1:15 and stirred evenly. The paddy seeds in each experimental group were completely immersed in the mixed solution. After soaking for 15 h, the paddy seeds were taken out and rinsed with water to remove the residual soaking solution. The rinsed paddy seeds were naturally dried in a cool and dry place. After pretreatment, the ICP-OES method was used to measure the contents of heavy metals such as cadmium (Cd), lead (Pb), mercury (Hg), and arsenic (As) in the paddy seeds, record the corresponding values and take the average, and the statistical results are shown in Table 2.

[0111] Table 2 Statistics of heavy metal contents in paddy seeds before and after soaking in each experimental group

[0112]

[0113] The comparison of heavy metal contents in paddy rice seeds before and after being soaked in the soaking solutions of each experimental group is shown in Table 2. The Chinese national standard (GB2762-2017) stipulates that the limits of cadmium (Cd), lead (Pb), mercury (Hg) and arsenic (As) in paddy rice seeds are 0.2 mg / kg, 0.2 mg / kg, 0.02 mg / kg and 0.2 mg / kg respectively. As can be seen from Table 1, the contents of Cd, Pb and Hg in the selected paddy rice seeds all exceed the standards, and the content of As does not exceed the standard but is also at a relatively high level. After soaking the paddy rice seeds with the seed soaking solutions prepared by each experimental group, the heavy metal contents in the paddy rice seeds all decreased significantly. For example, in Example 1, the contents of Cd, Pb, Hg and As in the paddy rice seeds decreased from 0.25 mg / kg, 0.21 mg / kg, 0.030 mg / kg and 0.16 mg / kg to 0.12 mg / kg, 0.09 mg / kg, 0.013 mg / kg and 0.07 mg / kg respectively. By comparing the reduction levels of heavy metal contents in Example 1 with those in the experimental groups of Control Group 1, Control Group 2, Control Group 3 and Control Group 4, it can be found that the effects of the seed soaking solutions prepared by the experimental groups of Control Group 1, Control Group 2, Control Group 3 and Control Group 4 are not as good as that of the seed soaking solution prepared in Example 1. In particular, the seed soaking solutions prepared without polyacrylate-metal composite and ascorbic acid in Control Group 1 and Control Group 3 respectively have much lower adsorption and degradation abilities for heavy metals than other experimental groups. This shows that when the two substances of polyacrylate-metal composite and ascorbic acid are added simultaneously during the preparation of the seed soaking solution, the prepared seed soaking solution has more excellent adsorption and degradation abilities for heavy metals in paddy rice seeds, can significantly reduce the heavy metal contents in the seeds, and avoid the influence of the existence of heavy metals on the absorption of nutrients by the seeds.

[0114] After the above limited experiments, the seed soaking solution of Example 1 of the present invention has a significant effect when applied to the process of crop planting. By promoting the catalytic conversion of nutrients, generating reactive oxygen species to activate the enzymes inside the seeds, ending the dormant state of the seeds, increasing the metabolic rate of the seeds, and at the same time scavenging excessive reactive oxygen species and adsorbing and reducing the heavy metal contents in crop seeds, it effectively improves the absorption of nutrients by crop seeds. In short, polyacrylate-metal composite, modified nano-zinc oxide, hydrogen peroxide and ascorbic acid can indeed provide a suitable biological environment for seeds to germinate and absorb nutrients through their synergistic effects. Using natural active substances such as seaweed extracts to optimize the formula and introducing nanotechnology can improve the utilization rate and biological activity of the effective components of the seed soaking solution, and at the same time improve the absorption efficiency of seeds for nutrients, maintain the vitality of the seeds, thereby increasing the germination rate and germination potential of the seeds, enhancing the disease resistance and stress resistance of crops, and ultimately achieving the purpose of increasing crop yield and quality.

[0115] Finally, it should be noted that although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A seed soaking solution, characterized in that, It consists of the following raw materials in parts by weight: 2 - 6 parts of modified nano - zinc oxide, 1 - 2 parts of hydrogen peroxide, 2 - 8 parts of ascorbic acid, 5 - 10 parts of seaweed extract, 1 - 5 parts of potassium dihydrogen phosphate, 1 - 5 parts of proline, 1 - 5 parts of polysorbate - 20, 2 - 4 parts of polyethylene glycol, and 30 - 50 parts of purified water; The seed soaking solution further includes: Polyacrylate - metal composite material; The weight - ratio of the polyacrylate - metal composite material to the modified nano - zinc oxide is 2:(2 - 6); The specific surface area of the polyacrylate-metal composite material is 400~500 m 2 / g, and the nano size is 60~80 nm; The preparation method of the polyacrylate - metal composite material includes: S11. Add purified water into a container, and successively add calcium chloride, magnesium chloride, ferric chloride, and copper sulfate under stirring. The stirring temperature is 50 - 60 °C, and stir for 1 - 2 h until completely dissolved to obtain a mixed metal ion solution, and the concentration of the mixed metal ion solution is 1 - 1.5 mol / L; S12. Dissolve polyacrylic acid in purified water under stirring for 1 - 2 h. After complete dissolution, adjust the pH value to 7.0 - 7.5 with sodium hydroxide solution to obtain a polyacrylic acid solution; S13. At room temperature, slowly add the polyacrylic acid solution to the stirring mixed metal ion solution. The stirring speed is 500 - 600 rpm, and after stirring for 2 - 4 h, obtain a first mixed solution; S14. Add N,N - methylenebisacrylamide to the first mixed solution and continue stirring for 1 - 2 h, then raise the temperature to 60 - 80 °C. Add ammonium persulfate under nitrogen protection, and the reaction time is 6 - 8 h. Cool the reaction product to room temperature to obtain a second mixed solution; S15. Centrifuge the second mixed solution at a high speed with a centrifugal speed of 5000 - 8000 rpm for 15 - 20 min. Wash the separated solid with purified water 5 times, then place it in a vacuum drying oven for drying. The drying temperature is 50 - 60 °C, and the drying time is 24 - 30 h to obtain the polyacrylate - metal composite material, which is ground into a powder for standby; The preparation method of the modified nano - zinc oxide includes: S21. Take an appropriate amount of zinc acetate solid and dissolve it in absolute ethanol. The stirring temperature is 50 - 60 °C, and after stirring for 1 - 2 h, obtain a zinc acetate solution; S22. Drop the sodium hydroxide solution into the zinc acetate solution under stirring. The stirring temperature is 50 - 60 °C. After stirring for 2 - 4 h, add a surfactant, raise the temperature to 70 - 80 °C, and stir for 4 - 5 h to obtain a third mixed solution; S23. Let the third mixed solution stand for 3 - 4 h and then separate the solid and liquid. Wash the separated solid with absolute ethanol 5 times, then place it in a vacuum drying oven for drying. The drying temperature is 60 - 80 °C, and the drying time is 12 - 18 h to obtain a white solid; S24. Place the white solid in a muffle furnace for roasting. The heating rate is 2 - 5 °C / min, the roasting temperature is 400 - 450 °C, and the roasting time is 4 - 5 h to obtain nano - zinc oxide, which is ground into a powder to obtain nano - zinc oxide powder; S25. Under nitrogen protection, the nano-zinc oxide powder and 3-aminopropyltriethoxysilane are successively added to absolute ethanol, and refluxed and stirred for 8 - 10 h at a stirring temperature of 70 - 80 °C. The reaction product is cooled to room temperature to obtain a fourth mixed solution; S26. The fourth mixed solution is allowed to stand for 3 - 4 h and then solid-liquid separated. The separated solid is washed 5 times with absolute ethanol and then placed in a vacuum drying oven for drying at a drying temperature of 60 - 80 °C for 12 - 18 h to obtain modified nano-zinc oxide, which is ground into a powder form and reserved; The particle size of the modified nano-zinc oxide is 20-40 nm, the specific surface area is 100-120 m 2 / g, and the surface of the modified nano-zinc oxide contains amino groups.

2. The seed soaking solution according to claim 1, wherein, The mass ratio of the surfactant to the modified nano-zinc oxide is 8:(2 - 6).

3. The seed soaking solution according to claim 1, characterized in that The surfactant is one or more of cetyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, sodium lauryl sulfate, and sodium dodecyl sulfate.

4. A method for preparing a seed soaking solution, which is applied to prepare the seed soaking solution according to any one of claims 1 to 3, characterized in that, The method comprises the following steps: S31. Purified water is added to a container, and polysorbate-20 and polyethylene glycol are added to the purified water under stirring at a stirring temperature of 50 - 60 °C and stirred for 2 - 3 h until completely dissolved to obtain a fifth mixed solution; S32. Under stirring, the polyacrylate-metal composite material and the modified nano-zinc oxide are added to the fifth mixed solution. After stirring for 2 - 3 h, absolute ethanol is added for ultrasonic treatment at an ultrasonic frequency of 40 - 50 kHz and an ultrasonic temperature of 50 - 60 °C for 2 - 4 h to obtain a sixth mixed solution; S33. Under stirring, hydrogen peroxide, ascorbic acid, seaweed extract, potassium dihydrogen phosphate, and proline are successively added to the fifth mixed solution, and at the same time, water bath heating is carried out at a heating temperature of 60 - 80 °C for 4 - 5 h and stirred for 3 - 4 h until completely dissolved, and the pH value is adjusted to 6.5 - 7.0 with a sodium hydroxide solution to obtain a seed soaking solution.

Images