Method for preparing medicament from corn straws to prevent and control corn diseases

Abstract

The invention discloses a method for preventing and controlling corn diseases by using a medicament prepared from corn straws, belonging to the technical field of agricultural biologication.The method comprises the following steps: selecting dry and mildew-free corn straws, crushing, adding into a solvent, carrying out ultrasonic treatment, adding a precipitator, carrying out ice-bath treatment, filtering, concentrating, dispersing with water, adjusting the pH value, adding a stabilizer, and uniformly mixing to obtain a mixture; the medicament prepared from the corn straws is prepared. The corn straw as agricultural waste is wide in source and easy to obtain, and the dependence on limited natural resources can be reduced by utilizing the corn straw to prepare the medicament. Compared with the prior art in which pesticides are mostly adopted for disease prevention and control, the invention provides a more environment-friendly alternative scheme. Corn straw is rich in bioactive components such as flavonoid compounds and alkaloid, and the components have various bioactivities such as antibiosis, antioxidation and antivirus. Through a specific preparation process, the active ingredients can be extracted and retained, so that the medicament with the function of preventing and controlling the corn diseases is prepared.

Description

Technical Field

[0001] The invention belongs to the field of agricultural biotechnology, and in particular relates to a method for preparing a medicine for preventing and controlling corn diseases by utilizing corn stalks. Background Art

[0002] Corn not only plays an important role as raw material in light industry and pharmaceutical industry, but is also an indispensable export agricultural product and feed crop in foreign trade and animal husbandry industry.

[0003] However, in the process of corn cultivation and production, the damage of corn leaf blight is a serious challenge, especially in the spring corn planting area of ​​Northeast China, where corn leaf blight is one of the most important diseases. Corn leaf blight occurs throughout the entire growth period of corn, and is generally more serious in the middle and late stages of corn growth, especially after the tasseling stage.

[0004] After the large spot pathogen infects corn leaves, the spots expand rapidly along the veins and are not restricted by the veins, quickly forming large spindle-shaped spots with gray-brown centers. The general size is (50-100)×(8-15) (mm), and some can reach 200mm in length. When the disease is serious, the spots often merge and connect, causing the leaves to dry up, seriously affecting the yield and quality of corn. The yield loss of susceptible varieties can reach more than 30%.

[0005] The primary infection source of the disease mainly comes from the diseased and incompletely decomposed corn stalks left in the fields after the corn harvest in the previous year. In the spring of the following year, when the temperature and humidity conditions are suitable, the mycelium that overwinters in the diseased and incomplete stalks produces a large number of conidia, which are spread to healthy corn leaves with the help of natural forces such as air flow and rain, causing the initial infection.

[0006] At present, the use of chemical agents is still the most common means of field prevention and control of corn leaf blight. Agents such as fenpropimorph, myclobutanil, propiconazole, and cloves-tebuconazole are widely used. However, the pathogen mutates quickly, and the long-term use of drugs reduces the sensitivity of the pathogen to conventional agents, forming drug resistance. Moreover, excessive chemical residues will cause irreversible damage to the field ecosystem, which violates the environmental protection concept of green prevention and control and comprehensive management. Therefore, exploring more efficient and environmentally friendly strategies for the prevention and control of corn leaf blight and reducing dependence on chemical agents has become an urgent problem to be solved in this field. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing a medicine for preventing and controlling corn diseases by using corn stalks, so as to solve the problems existing in the above-mentioned prior art.

[0008] One of the technical solutions provided by the present invention:

[0009] A method for preparing a medicine using corn stalks comprises the following steps: selecting dry and mildew-free corn stalks, crushing them, adding them to a solvent, performing ultrasonic treatment, adding a precipitant, filtering, concentrating, dispersing them with water after ice bath treatment, adjusting the pH, adding a stabilizer, and preparing the medicine using corn stalks.

[0010] The solvent is ethanol aqueous solution.

[0011] The temperature of the ultrasonic treatment is 40-60°C, the time is 1-3h, and the power is 100-300W.

[0012] The precipitant is polyethylene glycol.

[0013] The added amount of polyethylene glycol (PEG) is 2-5% of the mass of corn stalks.

[0014] The pH is 5-7.

[0015] The amount of the stabilizer added is 1-2% of the mass of the concentrated product.

[0016] Corn stalks, as the main agricultural waste after corn harvest, contain rich bioactive ingredients, such as polyphenols, flavonoids, alkaloids, etc., which have potential antibacterial and antiviral activities. However, there are few studies on the application of corn stalks in the field of biopesticides, and there is a lack of technical solutions for efficient extraction and utilization. Although polyphenols have antibacterial and antiviral activities, the effect and safety of phenols in corn stalks directly used to prevent and control corn diseases have not been fully verified. In addition, phenolic compounds are often regarded as harmful byproducts, and measures need to be taken to reduce their harm to crops. PEG has a strong affinity with phenols, which helps the precipitation of polyphenols. After adding PEG, an ice bath treatment is performed to combine polyphenols with PEG and precipitate them, so that flavonoids and alkaloids are retained in the filtrate, and the ethanol in the solvent is concentrated to obtain an extract containing flavonoids and alkaloids. Flavonoids and alkaloids have poor stability in water, and their dispersion stability in the agent is improved by adding stabilizers such as sodium alginate or mannitol.

[0017] The second technical solution provided by the present invention is:

[0018] A medicine prepared by using corn stalks is prepared by the above-mentioned preparation method.

[0019] The third technical solution provided by the present invention is:

[0020] An application of the above-mentioned medicine prepared by using corn stalks in preventing and controlling corn diseases.

[0021] The corn disease is a disease of southern corn leaf blight.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects:

[0023] Corn stalks are agricultural waste with a wide range of sources and are easy to obtain. The use of corn stalks to prepare medicines can reduce dependence on limited natural resources. Compared with the use of pesticides for disease prevention and control in the prior art, the present invention provides a more environmentally friendly alternative. Corn stalks are rich in biologically active ingredients, such as flavonoids, alkaloids, etc., which have multiple biological activities such as antibacterial, antioxidant and antiviral. Through a specific preparation process, these active ingredients can be extracted and retained to prepare medicines with the function of preventing and controlling corn diseases. In addition to preventing and controlling diseases, medicines prepared from corn stalks may also have functions such as promoting crop growth and improving crop stress resistance. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] The embodiment of the present invention provides a method for preparing a medicine using corn stalks, comprising the following steps: selecting dry and mildew-free corn stalks, crushing them and adding them to a solvent, performing ultrasonic treatment, adding a precipitant, filtering, concentrating, dispersing them with water after ice bath treatment, adjusting the pH, adding a stabilizer, and preparing the medicine using corn stalks.

[0030] In some embodiments of the present invention, the solvent is an ethanol aqueous solution.

[0031] In some embodiments of the present invention, the temperature of the ultrasonic treatment is 40-60°C, the time is 1-3h, and the power is 100-300 W. Exemplarily, in the following preferred embodiments of the present invention, the temperature of the ultrasonic treatment is 40°C, 50°C, 60°C, or any range between the aforementioned ratios; the time of the ultrasonic treatment is 1h, 2h, 3h, or any range between the aforementioned ratios; the power of the ultrasonic treatment is 100W, 200W, 300W, or any range between the aforementioned ratios.

[0032] In some embodiments of the present invention, the precipitating agent is polyethylene glycol.

[0033] In some embodiments of the present invention, the amount of polyethylene glycol added is 2-5% of the mass of corn stalks. Exemplarily, in the following preferred embodiments of the present invention, the amount of polyethylene glycol added is 2.5%, 4%, 5% of the mass of corn stalks, or any range between the aforementioned ratios.

[0034] In some embodiments of the present invention, the pH is 5-7. Exemplarily, in the following preferred embodiments of the present invention, the pH is 5, 6, 7, or any range between the aforementioned ratios.

[0035] In some embodiments of the present invention, the stabilizer is selected from sodium alginate or mannitol. Exemplarily, in the following preferred embodiments of the present invention, the stabilizer is selected from sodium alginate.

[0036] In some embodiments of the present invention, the stabilizer is 1-2% of the mass of the concentrated product. Exemplarily, in the following preferred embodiments of the present invention, the stabilizer is 1%, 1.3%, 2% of the mass of the concentrated product, or any range between the foregoing proportions.

[0037] The embodiment of the present invention provides a medicine prepared by using corn stalks and obtained by the above-mentioned preparation method.

[0038] The embodiment of the present invention provides the use of the agent prepared by using the above-mentioned corn stalks in preventing and controlling corn diseases, wherein the corn disease is a disease of corn leaf blight.

[0039] It should be noted that the parts not described in detail in the embodiments of the present invention can be achieved by conventional means in the art, such as ice bath treatment, rotary evaporation concentration and the preparation of a suspension of spores of corn leaf blight.

[0040] The raw materials required for the examples of the present invention, except corn stalks, were all purchased from the market, wherein polyethylene glycol-8000 powder was purchased from Shanghai Donghui Chemical Technology Co., Ltd.; sodium alginate was purchased from Zhengzhou Kangyuan Chemical Products Co., Ltd.

[0041] Example 1

[0042] 1 kg of dry, mold-free corn stalks was crushed and passed through a 200-mesh sieve, then added to 1000 mL of an ethanol-water solvent (the volume ratio of ethanol to water was 2:8), ultrasonicated at 40°C (200 W, 2 h), 25 g of polyethylene glycol was added, and the mixture was treated in an ice bath for 0.5 h, filtered, and concentrated by rotary evaporation to obtain a solid powder, which was dispersed in water (the mass ratio of the solid powder to water was 1:1), and 1% of the mass of the solid powder of sodium alginate was added to prepare a medicine prepared using corn stalks.

[0043] Example 2

[0044] 1 kg of dry, mildew-free corn stalks was crushed and passed through a 200-mesh sieve, then added to 1000 mL of an ethanol-water solvent (the volume ratio of ethanol to water was 2:8), ultrasonicated at 40°C (100 W, 3 h), 50 g of polyethylene glycol was added, and the mixture was treated in an ice bath for 0.5 h, filtered, and concentrated by rotary evaporation to obtain a solid powder, which was dispersed in water (the mass ratio of the solid powder to water was 1:1), the pH was adjusted to 7 with a phosphate buffer, and 2% of the mass of the solid powder of sodium alginate was added to prepare a medicine prepared using corn stalks.

[0045] Example 3

[0046] 1 kg of dry, mold-free corn stalks was crushed and passed through a 200-mesh sieve, then added to 1000 mL of an ethanol-water solvent (the volume ratio of ethanol to water was 2:8), ultrasonicated at 60°C (300 W, 1 h), 40 g of polyethylene glycol was added, and the mixture was treated in an ice bath for 0.5 h, filtered, and concentrated by rotary evaporation to obtain a solid powder, which was dispersed in water (the mass ratio of the solid powder to water was 1:1), the pH was adjusted to 6 with a phosphate buffer solution, and 1.3% of the mass of the solid powder was added with sodium alginate to prepare a medicine prepared using corn stalks.

[0047] Comparative Example 1

[0048] Same as Example 1, except that polyethylene glycol was not added. The specific operation was as follows:

[0049] 1 kg of dry, mold-free corn stalks was crushed through a 200-mesh sieve, added into 1000 mL of an ethanol-water solvent (the volume ratio of ethanol to water was 2:8), ultrasonicated at 40°C (200 W, 2 h), and treated in an ice bath for 0.5 h. The mixture was filtered and concentrated by rotary evaporation to obtain a solid powder, which was dispersed in water (the mass ratio of the solid powder to water was 1:1), and 1% of the mass of the solid powder of sodium alginate was added to prepare a medicine prepared using corn stalks.

[0050] Comparative Example 2

[0051] Same as Example 1, except that an excess of polyethylene glycol is added. The specific operation is as follows:

[0052] 1 kg of dry, mold-free corn stalks was crushed and passed through a 200-mesh sieve, then added to 1000 mL of an ethanol-water solvent (the volume ratio of ethanol to water was 2:8), ultrasonicated at 40°C (200 W, 2 h), 80 g of polyethylene glycol was added, and the mixture was treated in an ice bath for 0.5 h, filtered, and concentrated by rotary evaporation to obtain a solid powder, which was dispersed in water (the mass ratio of the solid powder to water was 1:1), and 1% of the mass of the solid powder of sodium alginate was added to prepare a medicine prepared using corn stalks.

[0053] Experiment on soaking corn seeds in water

[0054] The tested corn variety is Tieyan 368. 450 healthy, disease-free, morphologically similar and full-grained corn seeds are selected and soaked in 50±5°C pure water for 20 minutes, and then soaked in the pre-prepared agent solution (each agent is diluted 5 times with water) and the clean water control for 15 hours respectively by Example 1-3 and Comparative Example 1-2, and 75 corn seeds are treated for each treatment. The completely soaked corn seeds are taken out and laid flat on a glass culture dish with a filter paper at the bottom and a diameter of 20 cm, 25 seeds per dish, and each group is repeated 3 times. Cultivate in a light culture room under the conditions of room temperature 25±2°C, humidity 45±5%, and 12h light and dark alternation. After spraying water once every 24 hours, seal with a transparent film to maintain humidity. When the height of the corn seedling exceeds the height of the culture dish, the film can be removed, and other management conditions remain the same.

[0055] Determination indicators: germination rate was measured on the 3rd day of corn seed culture; lateral root number and root length were measured on the 7th day; plant height was measured on the 10th day; superoxide dismutase (SOD) activity in corn seedlings was measured on the 12th day. The determination results are shown in Table 1.

[0056] Table 1

[0057]

[0058]

[0059] Note: Germination rate (%) = total number of germinations / total number of seeds × 100

[0060] It can be seen from Table 1 that the medicament prepared by using corn stalks can significantly improve the germination rate and growth of corn seedlings. Since no polyethylene glycol is added in Comparative Example 1, the prepared medicament contains a certain amount of polyphenols, which inhibits the germination of seeds and the growth of seedlings. When an excessive amount of polyethylene glycol is added, supersaturation occurs, and the polyethylene glycol aggregates and precipitates. During the precipitation process, the extracted flavonoids and alkaloids are also removed, resulting in a decrease in the effective components in the obtained medicament, thereby affecting the germination rate and growth.

[0061] SOD enzyme is often regarded as a protective enzyme or an inducible enzyme. SOD enzyme can eliminate O2 - , effectively slowing down and preventing the peroxidation process of membrane lipids, ensuring the integrity of cell membranes, and thus achieving the purpose of improving the plant's stress resistance. From the test results, it can be seen that when the agent prepared by the present invention is used for soaking, the SOD enzyme activity in the corn seedlings is significantly higher than that of the control example and clean water, indicating that the agent prepared by the present invention has a strong adverse stress effect on the corn seedlings after treatment, and the corn seedlings may enhance their resistance to adversity through the SOD enzyme activity.

[0062] Field test on the efficacy of pesticides against corn leaf blight

[0063] The preparation of a spore suspension of corn leaf blight was carried out at our experimental station in the fall of 2022 using the corn leaf blight strain (isolated and identified by the Institute of Plant Protection, Liaoning Academy of Agricultural Sciences) and the susceptible corn germplasm material was Liao 3162.

[0064] When the corn had grown to 6-7 leaves, the agents of Examples 1-3 and Comparative Examples 1-2 were evenly sprayed on the surface of the corn leaves, and the control was treated with an equal amount of clean water. 2 days later, at 6-7 pm, the pre-prepared corn leaf blight spore suspension (1×10 4 / mL) was evenly sprayed on the corn leaves, repeated several times, about 10mL was sprayed per plant, and water was sprayed twice in the morning and evening for 3 days to keep moist. 20 days after inoculation of corn leaf blight pathogen, 10 corn plants in the treatment area were randomly investigated and the disease conditions of the corn leaves were recorded. According to the corn leaf blight disease grade classification standard in Table 2, the disease grade was judged. Table 3 shows the disease results of Example 1-3, Comparative Example 1-2 and clean water.

[0065] Table 2

[0066]

[0067] Table 3

[0068] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Shimizu level Level 3 Level 3 Level 3 Level 4 Level 4 Level 5

[0069] It can be seen from Table 2 and Table 3 that, compared with spraying with clean water, the agent prepared by the present invention can effectively prevent and control corn leaf blight, providing a new prevention and control measure for the prevention and control of corn diseases.

[0070] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for preparing a medicine using corn stalks, characterized in that: The following steps are involved: Dry and mildew-free corn stalks are selected, crushed, added into a solvent, ultrasonically treated, a precipitant is added, ice-bathed, filtered, concentrated, dispersed with water, pH value is adjusted, a stabilizer is added, and a medicine prepared using corn stalks is prepared.

2. The preparation method according to claim 1, characterized in that: The solvent is ethanol aqueous solution.

3. The preparation method according to claim 1, characterized in that: The temperature of the ultrasonic treatment is 40-60°C, the time is 1-3h, and the power is 100-300W.

4. The preparation method according to claim 1, characterized in that: The precipitant is polyethylene glycol.

5. The preparation method according to claim 4, characterized in that: The added amount of the polyethylene glycol is 2-5% of the mass of the corn stalks.

6. The preparation method according to claim 1, characterized in that: The stabilizer is selected from sodium alginate or mannitol.

7. The preparation method according to claim 6, characterized in that: The amount of the stabilizer added is 1-2% of the mass of the concentrated product.

8. A medicine prepared by using corn stalks, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the agent prepared using corn stalks as claimed in claim 8 in preventing and controlling corn diseases.

10. The use according to claim 9, characterized in that: The corn disease is a disease of southern corn leaf blight.

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