Seed coating agent for enhancing drought resistance of couch grass in seedling stage and preparation method of seed coating agent

Abstract

The invention discloses a seed coating agent for enhancing drought resistance of couch grass in a seedling stage and a preparation method of the seed coating agent, and relates to the technical field of seed coating, in order to improve the drought resistance of cocksfoot seeds, the seed coating agent is prepared in a mode that multiple layers of coating agents are matched, and when an inner layer coating agent is prepared, the inner layer coating agent and the outer layer coating agent are matched; salicylic acid is added to serve as a growth regulator of the dactylis glomerata seeds to improve the drought tolerance of the dactylis glomerata seeds; when the outer layer coating agent is prepared, bentonite is modified, firstly, sulfuric acid leaching and calcination are carried out, so that bentonite pores are increased, and the air permeability of the bentonite is improved; and on the basis, a sulfonic acid group and a triazole group are further introduced into the bentonite, so that the adsorption and mildew resistance of the modified bentonite to moisture in soil are improved, and a comfortable environment is provided for seed germination.

Description

Technical Field

[0001] The present invention relates to the technical field of seed treatment, and specifically to a seed coating agent for enhancing the drought resistance of orchardgrass seedlings and a preparation method thereof. Background Art

[0002] Orchardgrass (Dactylis glomerata), as one of the four major gramineous forages in the world, has its core distribution areas in Sichuan, Yunnan, Xinjiang and other places in China. It is not only the main grass species for the construction of artificial grasslands in the south, but also a key reseeding species for the ecological restoration of natural grasslands. Conventional planting mostly adopts the autumn sowing mode to avoid the growth competition of weeds. However, the climate characteristics in the southern hilly areas are concentrated precipitation in summer and frequent droughts in autumn. Coupled with the normal trend of autumn and winter droughts caused by global climate change in recent years, the problems of decreasing emergence rate of orchardgrass and hindered growth of grassland productivity have become increasingly prominent;

[0003] At the technical application level, although the seed coating technology has been proven to improve the survival rate of plants by enhancing the stress resistance of seedlings, current research mainly focuses on the disease prevention and control and yield improvement of crops in arid areas in the north, and there is still a blank in the systematic research and development of characteristic grass species in southern grasslands (such as orchardgrass). Among the existing publicly available technologies, only the case of promoting the germination of orchardgrass by using the penicillin seed soaking method (Patent CN102687613B) has been seen. However, this technology may cause environmental pollution risks due to antibiotic residues and is difficult to meet the development needs of green agriculture. Therefore, developing an environment-friendly seed treatment technology and constructing an efficient establishment system for orchardgrass adapted to the climate characteristics of the south has become an urgent topic to break through the bottleneck of regional grassland ecological restoration. Summary of the Invention

[0004] The purpose of the present invention is to provide a seed coating agent for enhancing the drought resistance of orchardgrass seedlings and a preparation method thereof to solve the problems raised in the prior art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A seed coating agent for enhancing the drought resistance of orchardgrass seedlings has the following technical characteristics: The seed coating agent is composed of an inner seed coating agent and an outer seed coating agent;

[0006] The inner seed coating agent is composed of salicylic acid, polyvinyl alcohol and deionized water;

[0007] Among them, the content of salicylic acid in the inner seed coating agent is 30 - 80 mg / L, the content of polyvinyl alcohol is 5 - 10 wt%, and the balance is deionized water;

[0008] The outer seed coating agent is composed of modified bentonite, superabsorbent resin, polyvinyl alcohol and deionized water;

[0009] Among them, the content of modified bentonite in the outer seed coating agent is 25-34wt%, the superabsorbent polymer is 3-6wt%, the content of polyvinyl alcohol is 5-10wt%, and the balance is deionized water.

[0010] Furthermore, a preparation method of a seed coating agent for enhancing the drought resistance of Dactylis glomerata seedlings at the seedling stage includes the following steps:

[0011] S1. Prepare modified bentonite;

[0012] S11. Disperse bentonite into sulfuric acid solution, heat up to 45-55°C, carry out ultrasonic stirring treatment for 1-2.5h, then centrifuge to separate the precipitate, wash it with deionized water until neutral, under the protection of nitrogen atmosphere, heat and calcine the precipitate, after the calcination is completed, cool it to room temperature, and collect the calcined bentonite;

[0013] S12. Disperse the calcined bentonite into anhydrous ethanol, ultrasonically disperse it evenly, then add KH-560 and mix evenly, continue to add deionized water, carry out ultrasonic reaction in the dark for 8-18h, centrifuge to separate the precipitate and dry it to constant weight, and obtain epoxidized bentonite;

[0014] S13. Under the protection of nitrogen atmosphere, add 2,5-diaminobenzenesulfonic acid to deionized water, stir until evenly mixed, under the protection of nitrogen atmosphere, add 1,2,4-triazole-3-carboxylic acid to it, heat up to 85-90°C, stir and react in the dark for 4-12h, then rotary evaporate to remove the excess solvent to obtain the amino triazole intermediate;

[0015] S14. Disperse the amino triazole intermediate into dimethyl sulfoxide, add boron trifluoride to it and mix evenly, under the protection of nitrogen atmosphere, add epoxidized bentonite to it, heat up to 75-85°C, carry out ultrasonic oscillation reaction for 4-8h, centrifuge to separate the precipitate, wash it with deionized water and dry it to constant weight, grind it through a 200-mesh sieve to obtain modified bentonite;

[0016] S2. Prepare the seed coating agent;

[0017] S21. Dissolve salicylic acid, polyvinyl alcohol and deionized water into water in sequence to prepare the inner seed coating agent;

[0018] S22. Disperse the modified bentonite, superabsorbent polymer, polyvinyl alcohol and deionized water into water in sequence, stir evenly to prepare the outer seed coating agent.

[0019] Furthermore, in step S11, the calcination temperature is 430-450°C and the calcination duration is 2-4h.

[0020] Furthermore, in step S12, the mass ratio of the calcined bentonite, KH-560 and deionized water is 10:(5-20):(3-12).

[0021] Further, in step S13, by weight parts, the mass ratio of the 2,5-diaminobenzenesulfonic acid to the 1,2,4-triazole-3-carboxylic acid is 1:(0.5 - 0.7).

[0022] Further, in step S14, the mass ratio of the aminotriazole intermediate, boron trifluoride, and epoxidized bentonite is (0.1 - 1.2):(0.001 - 0.005):10.

[0023] Further, an application of a seed coating agent for enhancing the drought resistance of orchardgrass seedlings.

[0024] Further, when the coating agent is used for coating orchardgrass seeds, the specific steps are as follows:

[0025] a. Mix the orchardgrass seeds with the inner seed coating agent, stir to cover the seeds with a coating film, and dry at 30 - 40°C for 3 - 4 h to form an inner coating with a thickness of 0.8 - 1.2 mm for standby;

[0026] b. Mix the orchardgrass seeds with the inner coating with the outer coating agent, cover the seeds with a coating film again, and dry at 30 - 40°C for 3 - 4 h to form an outer coating with a thickness of 1 - 1.5 mm to complete the coating of the orchardgrass seeds.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] In order to improve the drought tolerance of orchardgrass seeds, the present invention prepares a seed coating agent for enhancing the drought resistance of orchardgrass seedlings. The present invention uses a multi-layer coating agent combination method to prepare the coating agent. When preparing the inner coating agent, the present invention uses polyvinyl alcohol as a film-forming agent and adds salicylic acid as a growth regulator for orchardgrass seeds to improve the drought tolerance of orchardgrass seeds. Orchardgrass often faces the problem of autumn drought during autumn sowing, and salicylic acid can induce the synthesis of osmotic adjustment substances in seeds, such as proline and other substances, control the seed osmotic pressure, enhance cell water retention, and thus relieve the inhibition of germination caused by drought stress; and on this basis, salicylic acid, as a natural plant metabolite, has the advantages of being green, pollution-free, degradable, and residue-free, and can effectively avoid the antibiotic pollution caused by soaking seeds with penicillin;

[0029] On this basis, the present invention also prepared an outer coating agent and added a superabsorbent resin and modified bentonite thereto. Both the superabsorbent resin and bentonite have extremely strong water absorption. However, untreated bentonite has relatively small pores by itself. Although it can play a role in water retention and absorption, it will also seriously affect the various life activities of plant seeds and even germination. Therefore, the present invention carried out a modification treatment on bentonite. First, through sulfuric acid acid leaching treatment, some soluble ions therein were dissolved out, and then further high-temperature calcination was carried out to further remove the residual organic matter therein at high temperature, thereby increasing the pores of bentonite and enhancing its air permeability. And on this basis, the present invention further used a silane coupling agent containing an epoxy group to modify bentonite, hydrolyzed the silane coupling agent to introduce epoxy groups on the surface of bentonite, and used 1,2,4-triazole-3-carboxylic acid and 2,5-diaminobenzenesulfonic acid as raw materials to synthesize an amino triazole intermediate containing amino, sulfonic acid groups and triazole groups, and mixed it with epoxidized bentonite with epoxy groups, and utilized the reaction between amino and epoxy groups to introduce sulfonic acid groups and triazole groups into bentonite. Among them, the introduced triazole group has a broad-spectrum anti-mildew and antibacterial effect, which can effectively avoid the harm of various molds to orchardgrass seeds during storage; and the introduced sulfonic acid group can effectively improve the hydrophilic performance of bentonite, enhance the adsorption of water in the soil by the modified bentonite, and provide a comfortable environment for seed germination. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, and do not constitute a limitation to the present invention. In the drawings:

[0031] Figure 1 is the emergence dynamics diagram of the coated seeds in Example 6 and the uncoated seeds in Comparative Example 4 under the condition of 80% field water holding capacity;

[0032] Figure 2 is the emergence dynamics diagram of the coated seeds in Example 6 and the uncoated seeds in Comparative Example 4 under the condition of 50% field water holding capacity;

[0033] Figure 3 is the column chart of the relative leaf water content of the coated seeds in Example 6 and the uncoated seeds in Comparative Example 4;

[0034] Figure 4 is the column chart of the biomass of the coated seeds in Example 6 and the uncoated seeds in Comparative Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0035] 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. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0036] Embodiment 1. A preparation method of a seed coating agent for enhancing the drought resistance of orchardgrass seedlings, comprising the following steps:

[0037] S1. Prepare modified bentonite;

[0038] S11. Disperse bentonite into a sulfuric acid solution with a concentration of 10 wt%, heat to 50 °C, perform ultrasonic stirring treatment for 2 h, then centrifuge to separate the precipitate, wash it with deionized water until neutral, under the protection of a nitrogen atmosphere, heat to 430 °C, heat and calcine the precipitate for 2.5 h, after the calcination is completed, cool to room temperature, and collect the calcined bentonite;

[0039] S12. By weight, disperse 10 parts of the calcined bentonite into anhydrous ethanol, ultrasonically disperse it evenly, then add 5 parts of KH-560 and mix evenly, continue to add 3 parts of deionized water, perform ultrasonic reaction in the dark for 16 h, then centrifuge to separate the precipitate and dry it to constant weight to obtain epoxidized bentonite;

[0040] S13. Under the protection of a nitrogen atmosphere, add 1 part of 2,5-diaminobenzenesulfonic acid to deionized water, stir until evenly mixed, under the protection of a nitrogen atmosphere, add 0.5 part of 1,2,4-triazole-3-carboxylic acid, heat to 87 °C, stir and react in the dark for 8 h, then rotary evaporate to remove the excess solvent to obtain an amino triazole intermediate;

[0041] S14. By weight, disperse 0.1 part of the amino triazole intermediate into dimethyl sulfoxide, add 0.001 part of boron trifluoride and mix evenly, under the protection of a nitrogen atmosphere, add 10 parts of epoxidized bentonite, heat to 80 °C, perform ultrasonic oscillation reaction for 4 h, then centrifuge to separate the precipitate, wash it with deionized water and dry it to constant weight, grind it through a 200-mesh sieve to obtain modified bentonite;

[0042] S2. Prepare the seed coating agent;

[0043] S21. Dissolve salicylic acid, polyvinyl alcohol and deionized water in water in sequence to prepare an inner-layer seed coating agent;

[0044] Among them, the content of salicylic acid in the inner-layer seed coating agent is 30 mg / L, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water;

[0045] S22. Disperse the modified bentonite, superabsorbent polymer resin, polyvinyl alcohol and deionized water into water in sequence. After stirring evenly, prepare the outer seed coating agent;

[0046] Among them, the content of modified bentonite in the outer seed coating agent is 25 wt%, the superabsorbent polymer resin is 4 wt%, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water.

[0047] Example 2. A preparation method of a seed coating agent for enhancing the drought resistance of orchardgrass seedlings at the seedling stage, comprising the following steps:

[0048] Compared with Example 1, this example increases the addition amounts of KH-560 and deionized water in step S12;

[0049] S1. Prepare modified bentonite;

[0050] S11. Disperse bentonite into a sulfuric acid solution with a concentration of 10 wt%. Heat up to 50 °C, perform ultrasonic stirring treatment for 2 h, then centrifuge to separate the precipitate, wash it with deionized water until neutral, under the protection of a nitrogen atmosphere, heat up to 430 °C, heat and calcine the precipitate for 2.5 h. After the calcination is completed, cool to room temperature, and collect the calcined bentonite;

[0051] S12. By weight, disperse 10 parts of the calcined bentonite into anhydrous ethanol. After ultrasonic dispersion is uniform, add 15 parts of KH-560 to it and mix evenly. Then continue to add 9 parts of deionized water. After ultrasonic reaction in the dark for 16 h, centrifuge to separate the precipitate and dry it to constant weight to obtain epoxidized bentonite;

[0052] S13. Under the protection of a nitrogen atmosphere, add 1 part of 2,5-diaminobenzenesulfonic acid to deionized water. After stirring until evenly mixed, under the protection of a nitrogen atmosphere, add 0.5 part of 1,2,4-triazole-3-carboxylic acid to it, heat up to 87 °C, stir and react in the dark for 8 h, then rotary evaporate to remove the excess solvent to obtain the amino triazole intermediate;

[0053] S14. By weight, disperse 0.1 part of the amino triazole intermediate into dimethyl sulfoxide, add 0.001 part of boron trifluoride to it and mix evenly. Under the protection of a nitrogen atmosphere, add 10 parts of epoxidized bentonite to it, heat up to 80 °C, perform ultrasonic oscillation reaction for 4 h, then centrifuge to separate the precipitate, wash it with deionized water and dry it to constant weight, and grind it through a 200-mesh sieve to obtain modified bentonite;

[0054] S2. Prepare the seed coating agent;

[0055] S21. Dissolve salicylic acid, polyvinyl alcohol and deionized water into water in sequence to prepare the inner seed coating agent;

[0056] Among them, the content of salicylic acid in the inner seed coating agent is 30 mg / L, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water;

[0057] S22. Disperse modified bentonite, superabsorbent polymer, polyvinyl alcohol and deionized water into water in sequence. After stirring evenly, prepare the outer seed coating agent;

[0058] Among them, the content of modified bentonite in the outer seed coating agent is 25 wt%, the superabsorbent polymer is 4 wt%, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water.

[0059] Example 3. A preparation method of a seed coating agent for enhancing the drought resistance of orchardgrass seedlings, comprising the following steps:

[0060] Compared with Example 2, this example increases the addition amount of 1,2,4-triazole-3-carboxylic acid in step S13;

[0061] S1. Prepare modified bentonite;

[0062] S11. Disperse bentonite into a sulfuric acid solution with a concentration of 10 wt%. Heat up to 50 °C, perform ultrasonic stirring treatment for 2 h, then centrifuge to separate the precipitate, wash it with deionized water until neutral, protect it under a nitrogen atmosphere, heat up to 430 °C, heat and calcine the precipitate for 2.5 h. After the calcination is completed, cool it to room temperature, and collect the calcined bentonite;

[0063] S12. By weight, disperse 10 parts of calcined bentonite into anhydrous ethanol. After ultrasonic dispersion, add 15 parts of KH-560 and mix evenly. Then continue to add 9 parts of deionized water. After ultrasonic reaction in the dark for 16 h, centrifuge to separate the precipitate and dry it to constant weight to obtain epoxidized bentonite;

[0064] S13. Protect it under a nitrogen atmosphere. By weight, add 1 part of 2,5-diaminobenzenesulfonic acid to deionized water. Stir until evenly mixed. Then, protect it under a nitrogen atmosphere, add 0.6 part of 1,2,4-triazole-3-carboxylic acid to it, heat up to 87 °C, stir and react in the dark for 8 h. After rotary evaporation to remove the excess solvent, obtain the amino triazole intermediate;

[0065] S14. By weight, disperse 0.1 part of the amino triazole intermediate into dimethyl sulfoxide. Add 0.001 part of boron trifluoride to it and mix evenly. Then, protect it under a nitrogen atmosphere, add 10 parts of epoxidized bentonite to it, heat up to 80 °C, perform ultrasonic oscillation reaction for 4 h, centrifuge to separate the precipitate, wash it with deionized water and dry it to constant weight, and grind it through a 200-mesh sieve to obtain modified bentonite;

[0066] S2. Prepare the seed coating agent;

[0067] S21. Dissolve salicylic acid, polyvinyl alcohol, and deionized water into water in sequence to prepare an inner seed coating agent;

[0068] Among them, the content of salicylic acid in the inner seed coating agent is 30 mg / L, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water;

[0069] S22. Disperse modified bentonite, superabsorbent polymer, polyvinyl alcohol, and deionized water into water in sequence. After stirring evenly, prepare an outer seed coating agent;

[0070] Among them, the content of modified bentonite in the outer seed coating agent is 25 wt%, the superabsorbent polymer is 4 wt%, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water.

[0071] Example 4. A preparation method of a seed coating agent for enhancing the drought resistance of orchardgrass seedlings at the seedling stage, comprising the following steps:

[0072] Compared with Example 3, this example further increases the addition amount of 1,2,4-triazole-3-carboxylic acid in step S13;

[0073] S1. Prepare modified bentonite;

[0074] S11. Disperse bentonite into a sulfuric acid solution with a concentration of 10 wt%. Heat to 50 °C, perform ultrasonic stirring treatment for 2 h, then centrifuge to separate the precipitate, wash it with deionized water until neutral, protect it under a nitrogen atmosphere, heat to 430 °C, heat and calcine the precipitate for 2.5 h. After the calcination is completed, cool to room temperature, and collect the calcined bentonite;

[0075] S12. By weight, disperse 10 parts of the calcined bentonite into absolute ethanol. After ultrasonic dispersion, add 15 parts of KH-560 and mix evenly. Then continue to add 9 parts of deionized water. After ultrasonic reaction in the dark for 16 h, centrifuge to separate the precipitate and dry it to constant weight to obtain epoxidized bentonite;

[0076] S13. Protect under a nitrogen atmosphere. By weight, add 1 part of 2,5-diaminobenzenesulfonic acid to deionized water, stir until evenly mixed, then protect under a nitrogen atmosphere, add 0.7 part of 1,2,4-triazole-3-carboxylic acid to it, heat to 87 °C, stir and react in the dark for 8 h, then rotary evaporate to remove the excess solvent to obtain an amino triazole intermediate;

[0077] S14. Disperse 0.1 part of the aminotriazole intermediate by weight into dimethyl sulfoxide, add 0.001 part of boron trifluoride thereto, mix evenly, protect under a nitrogen atmosphere, add 10 parts of epoxidized bentonite thereto, heat up to 80 °C, react under ultrasonic oscillation for 4 h, centrifuge to separate the precipitate, wash with deionized water and dry to constant weight, grind through a 200-mesh sieve to obtain modified bentonite;

[0078] S2. Prepare a seed coating agent;

[0079] S21. Dissolve salicylic acid, polyvinyl alcohol and deionized water in water in sequence to prepare an inner-layer seed coating agent;

[0080] Among them, the content of salicylic acid in the inner-layer seed coating agent is 30 mg / L, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water;

[0081] S22. Disperse modified bentonite, superabsorbent polymer, polyvinyl alcohol and deionized water in water in sequence, stir evenly to prepare an outer-layer seed coating agent;

[0082] Among them, the content of modified bentonite in the outer-layer seed coating agent is 25 wt%, the superabsorbent polymer is 4 wt%, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water.

[0083] Example 5. A preparation method of a seed coating agent for enhancing the drought resistance of orchardgrass seedlings at the seedling stage, comprising the following steps:

[0084] Compared with Example 3, this example increases the addition amount of the aminotriazole intermediate in step S14;

[0085] S1. Prepare modified bentonite;

[0086] S11. Disperse bentonite into a sulfuric acid solution with a concentration of 10 wt%, heat up to 50 °C, perform ultrasonic stirring treatment for 2 h, centrifuge to separate the precipitate, wash with deionized water until neutral, protect under a nitrogen atmosphere, heat up to 430 °C, heat and calcine the precipitate for 2.5 h, after the calcination is completed, cool to room temperature, and collect the calcined bentonite;

[0087] S12. Disperse 10 parts of the calcined bentonite by weight into absolute ethanol, ultrasonically disperse evenly, add 15 parts of KH-560 thereto and mix evenly, continue to add 9 parts of deionized water, react under ultrasonic irradiation in the dark for 16 h, centrifuge to separate the precipitate and dry to constant weight to obtain epoxidized bentonite;

[0088] S13. Under nitrogen atmosphere protection, add 1 part of 2,5-diaminobenzenesulfonic acid to deionized water by weight. After stirring until evenly mixed, under nitrogen atmosphere protection, add 0.6 part of 1,2,4-triazole-3-carboxylic acid to it. Heat up to 87 °C, stir and react for 8 h in the dark. After rotary evaporation to remove the excess solvent, an aminotriazole intermediate is obtained;

[0089] S14. Disperse 1.2 parts of the aminotriazole intermediate in dimethyl sulfoxide by weight. Add 0.001 part of boron trifluoride to it. After mixing evenly, under nitrogen atmosphere protection, add 10 parts of epoxidized bentonite to it. Heat up to 80 °C, ultrasonically oscillate and react for 4 h. Then centrifuge to separate the precipitate, wash it with deionized water and dry it to constant weight, and grind it through a 200-mesh sieve to obtain modified bentonite;

[0090] S2. Prepare a seed coating agent;

[0091] S21. Dissolve salicylic acid, polyvinyl alcohol and deionized water in water in sequence to prepare an inner-layer seed coating agent;

[0092] Among them, the content of salicylic acid in the inner-layer seed coating agent is 30 mg / L, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water;

[0093] S22. Disperse modified bentonite, superabsorbent polymer, polyvinyl alcohol and deionized water in water in sequence. After stirring evenly, prepare an outer-layer seed coating agent;

[0094] Among them, the content of modified bentonite in the outer-layer seed coating agent is 25 wt%, the superabsorbent polymer is 4 wt%, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water.

[0095] Example 6. A preparation method of a seed coating agent for enhancing the drought resistance of orchardgrass seedlings at the seedling stage, comprising the following steps:

[0096] Compared with Example 5, this example increases the addition amount of modified bentonite in step S22;

[0097] S1. Prepare modified bentonite;

[0098] S11. Disperse bentonite in a sulfuric acid solution with a concentration of 10 wt%. Heat up to 50 °C, ultrasonically stir and process for 2 h. Then centrifuge to separate the precipitate, wash it with deionized water until neutral. Under nitrogen atmosphere protection, heat up to 430 °C, heat and calcine the precipitate for 2.5 h. After the calcination ends, cool to room temperature, and collect the calcined bentonite;

[0099] S12. Disperse 10 parts of calcined bentonite in absolute ethanol by weight. After ultrasonic dispersion until uniform, add 15 parts of KH-560 to it and mix evenly. Then continue to add 9 parts of deionized water. After ultrasonic reaction in the dark for 16 h, centrifuge to separate the precipitate and dry it to constant weight to obtain epoxidized bentonite.

[0100] S13. Under the protection of nitrogen atmosphere, add 1 part of 2,5-diaminobenzenesulfonic acid to deionized water by weight. Stir until evenly mixed. Then, under the protection of nitrogen atmosphere, add 0.6 part of 1,2,4-triazole-3-carboxylic acid to it. Heat up to 87 °C and stir and react in the dark for 8 h. After rotary evaporation to remove the excess solvent, obtain the amino triazole intermediate.

[0101] S14. Disperse 1.2 parts of the amino triazole intermediate in dimethyl sulfoxide by weight. Add 0.001 part of boron trifluoride to it and mix evenly. Then, under the protection of nitrogen atmosphere, add 10 parts of epoxidized bentonite to it. Heat up to 80 °C and carry out ultrasonic oscillation reaction for 4 h. Centrifuge to separate the precipitate, wash it with deionized water and dry it to constant weight, and grind it through a 200-mesh sieve to obtain modified bentonite.

[0102] S2. Prepare the seed coating agent.

[0103] S21. Dissolve salicylic acid, polyvinyl alcohol and deionized water in water in sequence to prepare the inner layer seed coating agent.

[0104] Among them, the content of salicylic acid in the inner layer seed coating agent is 30 mg / L, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water.

[0105] S22. Disperse modified bentonite, superabsorbent polymer, polyvinyl alcohol and deionized water in water in sequence. After stirring evenly, prepare the outer layer seed coating agent.

[0106] Among them, the content of modified bentonite in the outer layer seed coating agent is 34 wt%, the superabsorbent polymer is 4 wt%, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water.

[0107] Comparative Example 1. A preparation method of a seed coating agent for enhancing the drought resistance of Dactylis glomerata seedlings at the seedling stage includes the following steps:

[0108] Compared with Example 1, in this comparative example, only ordinary bentonite is used to replace the modified bentonite in equal amount.

[0109] S1. Prepare the seed coating agent.

[0110] S11. Dissolve salicylic acid, polyvinyl alcohol and deionized water in water in sequence to prepare the inner layer seed coating agent.

[0111] Among them, the content of salicylic acid in the inner-layer seed coating agent is 30 mg / L, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water;

[0112] S2. Disperse modified bentonite, superabsorbent polymer, polyvinyl alcohol and deionized water into water in sequence. After stirring evenly, prepare the outer-layer seed coating agent;

[0113] Among them, the content of modified bentonite in the outer-layer seed coating agent is 25 wt%, the superabsorbent polymer is 4 wt%, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water.

[0114] Comparative Example 2. A preparation method of a seed coating agent for enhancing the drought resistance of Dactylis glomerata seedlings at the seedling stage, comprising the following steps:

[0115] Compared with Example 1, only calcined bentonite was prepared in this comparative example;

[0116] S1. Prepare calcined bentonite;

[0117] S11. Disperse bentonite into a sulfuric acid solution with a concentration of 10 wt%. Heat up to 50 °C, perform ultrasonic stirring treatment for 2 h, then centrifuge to separate the precipitate, wash it with deionized water until neutral, protect it under a nitrogen atmosphere, heat up to 430 °C, heat and calcine the precipitate for 2.5 h, end the calcination, cool to room temperature, and collect the obtained calcined bentonite;

[0118] S2. Prepare the seed coating agent;

[0119] S21. Dissolve salicylic acid, polyvinyl alcohol and deionized water into water in sequence to prepare the inner-layer seed coating agent;

[0120] Among them, the content of salicylic acid in the inner-layer seed coating agent is 30 mg / L, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water;

[0121] S22. Disperse calcined bentonite, superabsorbent polymer, polyvinyl alcohol and deionized water into water in sequence. After stirring evenly, prepare the outer-layer seed coating agent;

[0122] Among them, the content of calcined bentonite in the outer-layer seed coating agent is 25 wt%, the superabsorbent polymer is 4 wt%, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water.

[0123] Comparative Example 3. A preparation method of a seed coating agent for enhancing the drought resistance of Dactylis glomerata seedlings at the seedling stage, comprising the following steps:

[0124] Compared with Example 1, only the inner-layer coating agent was prepared in this comparative example;

[0125] S1. Prepare the seed coating agent;

[0126] Dissolve salicylic acid, polyvinyl alcohol, and deionized water in water in sequence to prepare a seed coating agent;

[0127] Among them, the content of salicylic acid in the inner-layer seed coating agent is 30 mg / L, the content of polyvinyl alcohol is 7 wt%, and the balance is deionized water.

[0128] Detection: Mix the seed coating agents prepared in Examples 1-6 and Comparative Examples 1-3 of this application with the same batch of orchardgrass seeds, and perform coating treatment on them to obtain detection specimens Examples 1-6 and Comparative Examples 1-3. The specific steps are as follows:

[0129] a. Mix the orchardgrass seeds with the inner-layer seed coating agent, stir to cover the seeds with a coating film, and dry at 38 °C for 3.5 h to form an inner coating with a thickness of 1 mm for standby;

[0130] b. Mix the inner-coated orchardgrass seeds with the outer-layer seed coating agent, cover the seeds with a coating film again, and dry at 40 °C for 4 h to form an outer coating with a thickness of 1.2 mm to complete the coating of the orchardgrass seeds.

[0131] Another detection specimen Comparative Example 4 is set up, using the same batch of orchardgrass seeds but without coating treatment;

[0132] Respectively take 1000 orchardgrass seeds of each of the above-prepared examples and comparative examples, and conduct germination rate and seedling establishment rate tests according to the "Rules for Testing Crop Seeds";

[0133] For the germinated seeds above, continue to cultivate and conduct seedling establishment rate tests on them;

[0134] Respectively take 1000 orchardgrass seeds of each of the above-prepared examples and comparative examples, place them in an environment of 25 ± 2 °C and a relative humidity of 65 ± 2%, and store them for 3 months respectively to detect whether mildew appears on their surfaces;

[0135] The detection results are shown in the following table;

[0136] Germination rate (%) Seedling rate (%) Mildew rate (%) Example 1 94.5 89.2 2.4 Example 2 95.6 90.4 2.1 Example 3 95.6 90.9 2.0 Example 4 95.6 91.0 1.9 Example 5 95.8 91.3 1.8 Example 6 97.2 92.1 1.5 Comparative Example 1 91.4 82.5 9.8 Comparative Example 2 92.8 86.2 8.1 Comparative Example 3 90.4 86.1 7.6 Comparative Example 4 84.2 70.4 7.1

[0137] Conduct a pot experiment on the coated seeds of Example 6 and the uncoated seeds of Comparative Example 4. Set two water levels of normal water supply (80% field water holding capacity) and drought stress (50% field water holding capacity) respectively, and sow them under the soil of 0.5-1 cm respectively to detect their germination rates, and detect the biomass and relative leaf water content 10 days after planting;

[0138] The detection results are shown in Figures 1-4 .

[0139] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. 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 described 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 coating agent for enhancing the drought resistance of orchardgrass seedlings, characterized in that: The seed coating agent is composed of an inner-layer seed coating agent and an outer-layer seed coating agent; The inner-layer seed coating agent is composed of salicylic acid, polyvinyl alcohol and deionized water; Among them, the content of salicylic acid in the inner-layer seed coating agent is 30-80 mg / L, the content of the polyvinyl alcohol is 5-10 wt%, and the balance is deionized water; The outer-layer seed coating agent is composed of modified bentonite, superabsorbent resin, polyvinyl alcohol and deionized water; Among them, the content of modified bentonite in the outer-layer seed coating agent is 25-34 wt%, the superabsorbent resin is 3-6 wt%, the content of polyvinyl alcohol is 5-10 wt%, and the balance is deionized water.

2. A preparation method of a seed coating agent for enhancing the drought resistance of Dactylis glomerata seedlings as described in claim 1, characterized in that, It includes the following steps: S1. Prepare modified bentonite; S11. Disperse bentonite into a sulfuric acid solution, heat up to 45-55 °C, perform ultrasonic stirring treatment for 1-2.5 h, then centrifuge to separate the precipitate, wash it with deionized water until neutral, and under the protection of a nitrogen atmosphere, heat and calcine the precipitate. After the calcination is completed, cool it to room temperature, and collect the calcined bentonite; S12. Disperse the calcined bentonite into absolute ethanol, ultrasonically disperse it evenly, add KH-560 to it and mix evenly, then continue to add deionized water, perform ultrasonic reaction in the dark for 8-18 h, centrifuge to separate the precipitate and dry it to constant weight, and obtain epoxidized bentonite; S13. Under the protection of a nitrogen atmosphere, add 2,5-diaminobenzenesulfonic acid to deionized water, stir until evenly mixed, then under the protection of a nitrogen atmosphere, add 1,2,4-triazole-3-carboxylic acid to it, heat up to 85-90 °C, stir and react in the dark for 4-12 h, then rotary evaporate to remove the excess solvent, and obtain an amino triazole intermediate; S14. Disperse the amino triazole intermediate into dimethyl sulfoxide, add boron trifluoride to it and mix evenly, then under the protection of a nitrogen atmosphere, add epoxidized bentonite to it, heat up to 75-85 °C, perform ultrasonic oscillation reaction for 4-8 h, centrifuge to separate the precipitate, wash it with deionized water and dry it to constant weight, grind it through a 200-mesh sieve, and obtain modified bentonite; S2. Prepare the seed coating agent; S21. Dissolve salicylic acid, polyvinyl alcohol and deionized water into water in sequence to prepare the inner-layer seed coating agent; S22. Disperse modified bentonite, superabsorbent resin, polyvinyl alcohol and deionized water into water in sequence, stir evenly, and prepare the outer-layer seed coating agent.

3. The preparation method of a seed coating agent for enhancing the drought resistance of Dactylis glomerata seedlings according to claim 2, characterized in that: In step S11, the calcination temperature is 430-450 °C, and the calcination duration is 2-4 h.

4. The preparation method of a seed coating agent for enhancing the drought resistance of Dactylis glomerata seedlings according to claim 2, characterized in that: In step S12, the mass ratio of the calcined bentonite, KH-560 and deionized water is 10:(5-20):(3-12).

5. The preparation method of a seed coating agent for enhancing the drought resistance of Dactylis glomerata L. seedlings according to claim 2, characterized in that: In step S13, by weight, the mass ratio of the 2,5-diaminobenzenesulfonic acid and 1,2,4-triazole-3-carboxylic acid is 1:(0.5-0.7).

6. The preparation method of a seed coating agent for enhancing the drought resistance of Dactylis glomerata seedlings according to claim 2, characterized in that: In step S14, the mass ratio of the amino triazole intermediate, boron trifluoride and epoxidized bentonite is (0.1-1.2):(0.001-0.005):

10.

7. Application of a seed coating agent for enhancing the drought resistance of orchardgrass seedlings as described in claim 1.

8. Use of the seed coating agent according to claim 7, characterized in that: When the coating agent is used for coating orchardgrass seeds, the specific steps are as follows: a. Mix the orchardgrass seeds with the inner seed coating agent, stir to cover the seeds with a coating film, and dry at 30 - 40 °C for 3 - 4 h to form an inner coating with a thickness of 0.8 - 1.2 mm for standby; b. Mix the orchardgrass seeds with the inner coating with the outer coating agent, cover the seeds with a coating film again, and dry at 30 - 40 °C for 3 - 4 h to form an outer coating with a thickness of 1 - 1.5 mm, thus completing the coating of the orchardgrass seeds.

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