Rape chemical male gametocide and preparation method thereof

Abstract

The invention belongs to the field of male gametocide preparation, and particularly relates to a chemical male gametocide for oilseed rape and a preparation method thereof. The chemical male gametocide for the oilseed rape comprises the compound chemical male gametocide nanoparticles and the pH response compound, the compound chemical male gametocide nanoparticles are obtained by encapsulating paclobutrazol and epoxy sulfuron methyl with hydroxyethyl starch modified by oleic acid, and the chemical male gametocide has the advantages of improving the bioavailability and the like; the pH response compound is obtained by treating an all-silicon mesoporous molecular sieve and carrying out double-step treatment and chemical modification by using 3-aminopropyl (diethoxy) methylsilane and poly (ethyl acrylate), and is damaged in a slightly alkaline environment, so that quick release of the content is realized. The chemical male gametocide for the oilseed rape has a pH response characteristic, can accurately act on male reproductive organs of the oilseed rape, can cause related characters of male sterility, has different degrees of inhibition on plant height, main inflorescence length and the like, and can thoroughly emasculate under a relatively low application amount, so that the purity of hybrid seeds is ensured, and relatively good economic benefits are obtained.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of male sterility agents, and particularly relates to a chemical male sterility agent for rapeseed and a preparation method thereof. Background Art

[0002] Rapeseed is an important oil crop. Rapeseed hybrids have the following advantages: 1) Vegetative growth advantage: strong emergence potential, strong plant growth potential, thick stems, lush branches and leaves, increased vegetative body and extended green-holding period; 2) Physiological advantage of plants: Its seeds show outstanding performance in physiological indexes such as water absorption rate, photosynthetic area, lipase activity and vascular bundle number compared with conventional rapeseed; 3) Stress resistance advantage: The growth period of rapeseed hybrids is between the two parents and tends to be early-maturing parent; 4) Yield advantage: Rapeseed hybrid seed production is convenient, with less investment and high efficiency; 5) Quality trait advantage: Rapeseed hybrids have a high oil content and better uniformity.

[0003] Chemical male sterility agents interfere with the physiological and biochemical processes of plant male reproductive organs, inhibit the formation or development of pollen, resulting in male sterility, thus facilitating cross-breeding. Chemical male sterility agents can inhibit the expression of specific genes, such as inducing pollen abortion in Brassica napus by regulating the RA gene, or causing abortion by inducing endogenous hormone disorders, or causing the anthers to lack nutrition and unable to develop normally, resulting in sterility, or causing male sterility in plants due to the disorder of the membrane lipid peroxidation mechanism.

[0004] Existing rapeseed chemical male sterility agents have the following problems: 1) Insufficient efficacy stability: Since most male sterility agents are systemic agents, their absorption and conduction efficiency are sensitive to environmental conditions, and external factors may interfere with their action mechanism; 2) Potential impact on non-target organisms: Male sterility agents have certain chemical activities and may diffuse into the environment through volatilization, runoff, etc., having a negative impact on other organisms and even affecting the balance of the ecosystem; 3) Residual problems: Some male sterility agents remain in the plant or soil... Summary of the Invention

[0005] Based on the above problems, the present invention provides a chemical male sterility agent for rapeseed, which comprises a compound chemical sterilant nanoparticle and a pH-responsive complex. The compound chemical sterilant nanoparticle is obtained by encapsulating paclobutrazol and oxasulfuron with hydroxyethyl starch modified by oleic acid, and has advantages such as improving bioavailability; the pH-responsive complex is obtained by treating a fully silicon mesoporous molecular sieve and chemically modifying it by double-step treatment with 3-aminopropyl(diethoxy)methylsilane and polyethyl acrylate, and is damaged in a slightly alkaline environment, thus realizing the rapid release of the content. The rapeseed chemical male sterility agent obtained by the present invention has a pH-responsive property, can accurately act on the male reproductive organs of rapeseed, can cause related traits of male sterility, has different degrees of inhibition on plant height, main inflorescence length, etc., and can completely emasculate at a lower application rate, thus ensuring the purity of hybrid seeds.

[0006] The present invention provides a chemical male sterilant for rapeseed, which comprises the following raw materials in parts by weight: 8-12 parts of compound chemical sterilant nanoparticles and 3-5 parts of pH-responsive complex.

[0007] The preparation method of the compound chemical sterilant nanoparticles is as follows: L1. Dissolve hydroxyethyl starch in water to obtain a hydroxyethyl starch solution with a mass percentage concentration of 8-10%. Weigh the hydroxyethyl starch solution and potassium periodate solution according to a volume ratio of 1:0.8-1, adjust the pH to 3.0, and stir at a speed of 150-200 rpm in the dark for 2-3 h to obtain liquid A after completion. L2. Weigh liquid A obtained in step L1 and absolute ethanol according to a volume ratio of 1:2-3, let it stand at room temperature for 5-8 h, dialyze with a dialysis bag with a cut-off molecular weight of 3000 Da for 48-56 h, collect the substances in the dialysis bag, and obtain substance A after vacuum freeze-drying. L3. Weigh substance A obtained in step L2 and oleic acid according to a mass-volume ratio of 1-2 g:5-6 mL, heat to 60-80 °C, stir at a speed of 150-180 rpm for 1-2 h, dialyze with a dialysis bag with a cut-off molecular weight of 10000 Da for 30-40 h, and obtain substance B after vacuum freeze-drying at the end. L4. Dissolve paclobutrazol and oxyfluorfen in acetone to obtain liquid B. Add substance B obtained in step L3 to liquid B, perform ultrasonic treatment at a power of 200-250 W for 20-30 min, and then perform spray drying to obtain the compound chemical sterilant nanoparticles.

[0008] Preferably, the mass percentage concentration of the potassium periodate solution in step L1 is 6-8%.

[0009] Preferably, in step L4, the concentration of paclobutrazol in liquid B is preferably 2-4 g / L, the concentration of oxyfluorfen is preferably 4-5 g / L, the addition amount of substance B is 6-8 g / L, and the spray drying is preferably carried out at an air flow rate of 1.5-2 m 3 / min, an inlet air temperature of 80-90 °C, and an outlet air temperature of 65-75 °C.

[0010] The preparation method of the pH-responsive complex is as follows: S1. Weigh fumed silica mesoporous molecular sieve and toluene according to a mass-volume ratio of 200-240 mg:30-40 mL, stir at a speed of 100-150 rpm until evenly dispersed to obtain liquid C. Weigh liquid C and 3-aminopropyl(diethoxy)methylsilane according to a volume ratio of 8-10:1, heat to 80-90 °C, and continuously stir at a speed of 180-200 rpm for 10-15 h. After completion, naturally cool to room temperature, wash thoroughly with methanol, and the obtained product is dried to obtain substance C. S2. Weigh the substance C, dimethylformamide, and polyethyl acrylate obtained in step S1 according to the mass-volume ratio of 100 - 120 mg : 40 - 50 mL : 200 - 300 mg, heat to 120 - 130 °C, continuously stir at a speed of 250 - 300 rpm for 2 - 3 h, and after completion, centrifuge at a centrifugal force of 6000 - 8000 g for 20 - 30 min to obtain a precipitate; S3. Wash the precipitate obtained in step S2 with methanol, and then dry it to obtain the pH-responsive complex.

[0011] Preferably, in step S1, the fully siliceous mesoporous molecular sieve is preferably MCM-14 with a particle size of 100 nm, and the CAS number of 3-aminopropyl(diethoxy)methylsilane is 3179-76-8.

[0012] Preferably, in step S2, the Mw of polyethyl acrylate is preferably 6000 - 7000.

[0013] Preferably, in step S3, the drying is preferably carried out at 45 - 50 °C.

[0014] The present invention also provides a preparation method of a chemical male sterilant for rapeseed, and the specific steps are as follows: Add the compound chemical sterilant nanoparticles into methanol, stir at a speed of 100 - 120 rpm until evenly dispersed, then add the pH-responsive complex, and continue to stir at the same speed for 1 - 1.5 h. After completion, remove methanol by rotary evaporation at 60 - 65 °C to obtain the chemical male sterilant for rapeseed of the present invention.

[0015] Preferably, in the preparation method of the chemical male sterilant for rapeseed, the dosage of methanol is preferably 3 - 5 times the weight part of the compound chemical sterilant nanoparticles.

[0016] The beneficial effects of the present invention are as follows: The present invention processes hydroxyethyl starch, modifies it with oleic acid after activation, and the obtained substance B has good loading and encapsulation characteristics, can effectively stabilize paclobutrazol and oxyfluorfen, and while avoiding the mutual influence between paclobutrazol and oxyfluorfen, obtains compound chemical pesticide nano-particles with small particle sizes, which can not only enhance the contact area during application, but also improve the bioavailability. The present invention further processes all-silica mesoporous molecular sieves, and chemically modifies them by two-step treatment with 3-aminopropyl(diethoxy)methylsilane and polyethyl acrylate, and the obtained pH-responsive composite can be damaged in a slightly alkaline environment, so as to realize the rapid release of the content. After mixing and treating the above compound chemical pesticide nano-particles with the pH-responsive composite, the obtained chemical male sterility agent for rape, through simulated release experiments, at pH = 7.0, at least 50% of paclobutrazol can be released in 80 min, and at 120 min, 69.74% of paclobutrazol can be released. This pH-responsive characteristic helps the chemical male sterility agent for rape obtained by the present invention to act precisely on the male reproductive organs of rape and reduce the impact on non-target organisms. Field experiments show that the chemical male sterility agent for rape obtained by the present invention can cause related traits of male sterility, and has different degrees of inhibition on plant height, main inflorescence length, etc. At the application rate of 0.5 kg / mu, the relative seed setting rate of the female parent is at most 10.0%, indicating that the male sterility agent treatment is successful, the emasculation is complete, and the purity of the hybrid can be better guaranteed. With the increase of the application rate, the male sterility effect is better. In addition, by applying the chemical male sterility agent for rape obtained by the present invention at an appropriate dose, better economic benefits can be obtained. Description of the Drawings

[0017] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation to the present application. In the drawings: Figure 1 It is a graph of the results of simulated sustained release experiments at different pH values; Figure 2 It is a graph of the results of the pistil length, stamen length, petal length, and petal width after treatment with the chemical male sterility agent for rape; Figure 3 It is a graph of the results of the plant height and main inflorescence length after treatment with the chemical male sterility agent for rape; Figure 4 It is a graph of the results of the silique length and the number of primary branches after treatment with the chemical male sterility agent for rape; Figure 5 It is a graph of the results of the number of grains per silique and the total number of grains after treatment with the chemical male sterility agent for rape; Figure 6 It is a graph of the results of the yield and relative yield after treatment with the chemical male sterility agent for rape. Detailed Embodiments

[0018] To more clearly illustrate the overall concept of this application, the following provides a detailed description by way of examples in conjunction with the accompanying drawings of the specification. In the following description, numerous specific details are given to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without one or more of these details. In other instances, some well-known technical features are not described to avoid confusion with the present invention.

[0019] Example 1: This example provides a method for preparing compound chemical pesticide nanoparticles, and the specific steps are as follows: L1. Dissolve hydroxyethyl starch in water to obtain a hydroxyethyl starch solution with a mass percentage concentration of 8%. Weigh the hydroxyethyl starch solution and a potassium periodate solution with a mass percentage concentration of 6% according to a volume ratio of 1:0.8, adjust the pH to 3.0, and stir at a speed of 150 rpm for 2 h in a dark environment. After completion, obtain liquid A; L2. Weigh liquid A obtained in step L1 and absolute ethanol according to a volume ratio of 1:2, let stand at room temperature for 5 h, dialyze for 48 h using a dialysis bag with a molecular weight cut-off of 3000 Da, collect the substances in the dialysis bag, and obtain substance A after vacuum freeze-drying; L3. Weigh substance A obtained in step L2 and oleic acid according to a mass-volume ratio of 1 g:5 mL, heat to 60 °C, stir at a speed of 150 rpm for 1 h, dialyze for 30 h using a dialysis bag with a molecular weight cut-off of 10000 Da, and obtain substance B after vacuum freeze-drying at the end; L4. Dissolve paclobutrazol and oxycarboxin in acetone to obtain liquid B. The concentration of paclobutrazol in liquid B is 2 g / L, and the concentration of oxycarboxin is 4 g / L. Add substance B obtained in step L3 to liquid B, and the addition amount of substance B is 6 g / L. Ultrasonically treat for 20 min at a power of 200 W. After completion, perform spray drying at an air flow rate of 1.5 m 3 / min, an inlet air temperature of 80 °C, and an outlet air temperature of 65 °C to obtain compound chemical pesticide nanoparticles.

[0020] Example 2: This example provides a method for preparing compound chemical pesticide nanoparticles, and the specific steps are as follows: L1. Dissolve hydroxyethyl starch in water to obtain a hydroxyethyl starch solution with a mass percentage concentration of 9%. Weigh the hydroxyethyl starch solution and a potassium periodate solution with a mass percentage concentration of 7% according to a volume ratio of 1:0.9, adjust the pH to 3.0, and stir at a speed of 180 rpm for 2.5 h in a dark environment. After completion, obtain liquid A; L2. Weigh the liquid A obtained in step L1 and absolute ethanol according to a volume ratio of 1:2.5, let it stand at room temperature for 7 h, dialyze it for 52 h using a dialysis bag with a molecular weight cut-off of 3000 Da, collect the substances in the dialysis bag, and obtain substance A after vacuum freeze-drying; L3. Weigh substance A obtained in step L2 and oleic acid according to a mass-volume ratio of 1.5 g:5.5 mL, heat it to 70 °C, stir it at a rotation speed of 160 rpm for 1.5 h, dialyze it for 34 h using a dialysis bag with a molecular weight cut-off of 10000 Da, and obtain substance B after vacuum freeze-drying at the end; L4. Dissolve paclobutrazol and oxyfluorfen in acetone to obtain liquid B. The concentration of paclobutrazol in liquid B is 3 g / L, and the concentration of oxyfluorfen is 4.5 g / L. Add substance B obtained in step L3 to liquid B, and the addition amount of substance B is 7 g / L. Ultrasonically treat it for 27 min at a power of 240 W. After that, perform spray drying under an air flow rate of 1.8 m 3 / min, an inlet air temperature of 85 °C, and an outlet air temperature of 70 °C to obtain the compound chemical pesticide nanoparticles.

[0021] Example 3: This example provides a method for preparing compound chemical pesticide nanoparticles, and the specific steps are as follows: L1. Dissolve hydroxyethyl starch in water to obtain a hydroxyethyl starch solution with a mass percentage concentration of 10%. Weigh the hydroxyethyl starch solution and a potassium periodate solution with a mass percentage concentration of 8% according to a volume ratio of 1:1, adjust the pH to 3.0, stir it at a rotation speed of 200 rpm in a dark environment for 3 h, and obtain liquid A at the end; L2. Weigh the liquid A obtained in step L1 and absolute ethanol according to a volume ratio of 1:3, let it stand at room temperature for 8 h, dialyze it for 56 h using a dialysis bag with a molecular weight cut-off of 3000 Da, collect the substances in the dialysis bag, and obtain substance A after vacuum freeze-drying; L3. Weigh substance A obtained in step L2 and oleic acid according to a mass-volume ratio of 2 g:6 mL, heat it to 80 °C, stir it at a rotation speed of 180 rpm for 2 h, dialyze it for 40 h using a dialysis bag with a molecular weight cut-off of 10000 Da, and obtain substance B after vacuum freeze-drying at the end; L4. Dissolve paclobutrazol and oxyfluorfen in acetone to obtain liquid B. The concentration of paclobutrazol in liquid B is 4 g / L, and the concentration of oxyfluorfen is 5 g / L. Add substance B obtained in step L3 to liquid B, and the addition amount of substance B is 8 g / L. Ultrasonically treat it for 30 min at a power of 250 W. After that, perform spray drying under an air flow rate of 2 m 3 / min, an inlet air temperature of 90 °C, and an outlet air temperature of 75 °C to obtain the compound chemical pesticide nanoparticles.

[0022] Example 4: This example provides a method for preparing a pH-responsive complex, and the specific steps are as follows: S1. Weigh the all-silica mesoporous molecular sieve and toluene according to the mass-volume ratio of 200 mg: 30 mL. The all-silica mesoporous molecular sieve is MCM-14 with a particle size of 100 nm. After stirring at a speed of 100 rpm until evenly dispersed, liquid C is obtained. Weigh liquid C and 3-aminopropyl(diethoxy)methylsilane according to the volume ratio of 8:1, heat to 80 °C, and continuously stir at a speed of 180 rpm for 10 h. After completion, naturally cool to room temperature, and wash thoroughly with methanol. The obtained product is dried to obtain substance C; S2. Weigh substance C, dimethylformamide, and polyethyl acrylate obtained in step S1 according to the mass-volume ratio of 100 mg: 40 mL: 200 mg. The Mw of polyethyl acrylate is 6000. Heat to 120 °C and continuously stir at a speed of 250 rpm for 2 h. After completion, centrifuge at a centrifugal force of 6000 g for 20 min to obtain a precipitate; S3. Wash the precipitate obtained in step S2 with methanol, and then dry it at 45 °C to obtain the pH-responsive complex.

[0023] Example 5: This example provides a method for preparing a pH-responsive complex, and the specific steps are as follows: S1. Weigh the all-silica mesoporous molecular sieve and toluene according to the mass-volume ratio of 220 mg: 35 mL. The all-silica mesoporous molecular sieve is MCM-14 with a particle size of 100 nm. After stirring at a speed of 120 rpm until evenly dispersed, liquid C is obtained. Weigh liquid C and 3-aminopropyl(diethoxy)methylsilane according to the volume ratio of 9:1, heat to 85 °C, and continuously stir at a speed of 190 rpm for 12 h. After completion, naturally cool to room temperature, and wash thoroughly with methanol. The obtained product is dried to obtain substance C; S2. Weigh substance C, dimethylformamide, and polyethyl acrylate obtained in step S1 according to the mass-volume ratio of 110 mg: 45 mL: 240 mg. The Mw of polyethyl acrylate is 6500. Heat to 125 °C and continuously stir at a speed of 280 rpm for 2.5 h. After completion, centrifuge at a centrifugal force of 7000 g for 25 min to obtain a precipitate; S3. Wash the precipitate obtained in step S2 with methanol, and then dry it at 50 °C to obtain the pH-responsive complex.

[0024] Example 6: This example provides a method for preparing a pH-responsive complex, and the specific steps are as follows: S1. Weigh the all-silica mesoporous molecular sieve and toluene according to the mass-volume ratio of 240 mg: 40 mL. The all-silica mesoporous molecular sieve is MCM-14 with a particle size of 100 nm. After stirring at a speed of 150 rpm until evenly dispersed, liquid C is obtained. Weigh liquid C and 3-aminopropyl(diethoxy)methylsilane according to the volume ratio of 10:1, heat to 90 °C, and continuously stir at a speed of 200 rpm for 15 h. After completion, naturally cool to room temperature, and wash thoroughly with methanol. The obtained product is dried to obtain substance C; S2. Weigh the substance C, dimethylformamide, and polyethyl acrylate obtained in step S1 according to the mass-volume ratio of 120 mg: 50 mL: 300 mg. The Mw of polyethyl acrylate is 7000. Heat to 130 °C and continuously stir at a speed of 300 rpm for 3 h. After completion, centrifuge at a centrifugal force of 8000 g for 30 min to obtain a precipitate; S3. Wash the precipitate obtained in step S2 with methanol, and then dry it at 55 °C to obtain the pH-responsive composite.

[0025] Example 7: This example provides a preparation method of a chemical male sterility agent for rapeseed, and the specific steps are as follows: The chemical male sterility agent for rapeseed in this example contains the following raw materials in parts by weight: 8 parts of compound chemical male sterility agent nanoparticles, 3 parts of pH-responsive composite. The compound chemical male sterility agent nanoparticles are obtained by the preparation in Example 1, and the pH-responsive composite is obtained by the preparation in Example 4; Add the compound chemical male sterility agent nanoparticles to methanol. The amount of methanol used is 3 times the weight part of the compound chemical male sterility agent nanoparticles. After stirring at a speed of 100 rpm until evenly dispersed, add the pH-responsive composite, and continue to stir at the same speed for 1 h. After completion, remove methanol by rotary evaporation at 60 °C to obtain the chemical male sterility agent of the present invention.

[0026] Example 8: This example provides a preparation method of a chemical male sterility agent for rapeseed, and the specific steps are as follows: The chemical male sterility agent for rapeseed in this example contains the following raw materials in parts by weight: 10 parts of compound chemical male sterility agent nanoparticles, 4 parts of pH-responsive composite. The compound chemical male sterility agent nanoparticles are obtained by the preparation in Example 2, and the pH-responsive composite is obtained by the preparation in Example 5; Add the compound chemical male sterility agent nanoparticles to methanol. The amount of methanol used is 4 times the weight part of the compound chemical male sterility agent nanoparticles. After stirring at a speed of 110 rpm until evenly dispersed, add the pH-responsive composite, and continue to stir at the same speed for 1.2 h. After completion, remove methanol by rotary evaporation at 62 °C to obtain the chemical male sterility agent of the present invention.

[0027] Example 9: This example provides a preparation method of a chemical male sterility agent for rapeseed, and the specific steps are as follows: The chemical male sterility agent for rape in this example comprises raw materials in the following weight parts: 12 parts of compound chemical male sterility agent nanoparticles, 5 parts of pH-responsive complex. The compound chemical male sterility agent nanoparticles are obtained by preparation in Example 3, and the pH-responsive complex is obtained by preparation in Example 6. Add the compound chemical male sterility agent nanoparticles into methanol. The dosage of methanol is 5 times the weight part of the compound chemical male sterility agent nanoparticles. After stirring evenly at a speed of 120 rpm, add the pH-responsive complex and continue stirring for 1.5 h at the same speed. After completion, remove methanol by rotary evaporation at 65 °C to obtain the chemical male sterility agent for rape of the present invention.

[0028] Comparative Example 1: This comparative example provides a chemical male sterility agent for rape, with the main component being paclobutrazol. The total content of paclobutrazol is 15%, produced by Hainan Limengte Biotechnology Co., Ltd., and the registration number is PD20151521.

[0029] Comparative Example 2: This comparative example provides a chemical male sterility agent for rape, with the main component being oxasulfuron. The total content of oxasulfuron is 75%, self-prepared. The oxasulfuron is purchased from Merck Chemical Technology (Shanghai) Co., Ltd.

[0030] Experimental test: I. Simulated release experiment: Prepare an aqueous solution of disodium hydrogen phosphate dodecahydrate with a concentration of 0.2 mol / L, denoted as Solution 1, and prepare an aqueous solution of sodium dihydrogen phosphate dihydrate with a concentration of 0.2 mol / L, denoted as Solution 2. According to the corresponding volume ratios, buffer solutions with different pH values are obtained respectively. Buffer solution with pH 5.8: 8 mL of Solution 1, 92 mL of Solution 2; buffer solution with pH 6.0: 12.3 mL of Solution 1, 87.7 mL of Solution 2; buffer solution with pH 6.5: 31.5 mL of Solution 1, 68.5 mL of Solution 2; buffer solution with pH 6.6: 37.5 mL of Solution 1, 62.5 mL of Solution 2; buffer solution with pH 7.0: 62 mL of Solution 1, 38 mL of Solution 2; buffer solution with pH 7.4: 81 mL of Solution 1, 19 mL of Solution 2; buffer solution with pH 7.5: 84 mL of Solution 1, 16 mL of Solution 2; buffer solution with pH 8.0: 94.7 mL of Solution 1, 5.3 mL of Solution 2. When used for the simulated slow-release experiment, a methanol solution accounting for 30% of the volume of the above buffer solutions is added to all the buffer solutions.

[0031] Weigh 20 mg of the chemical male sterility agent for rape prepared in Example 7 into a centrifuge tube, add 80 mL of buffer solutions with different pH values, place it in a full-temperature shaking incubator, and sample at different time periods under the conditions of 25 °C and 50 rpm in the dark. After pipetting 3 mL of the supernatant with a pipette, supplement the same dose of the same buffer solution and measure the concentration of the supernatant with a UV spectrophotometer to calculate the cumulative release rate. Each group is performed in 3 parallels. The cumulative release rate formula is as follows:

[0032] where C t is the drug concentration in the solution at the t-th sampling, V is the total volume of the solution, V e is the volume of the solution for a single sampling, and m is the actual drug loading amount.

[0033] The results of the simulated sustained-release experiment are as Figure 1 shown. It can be seen from Figure 1 that the chemical male-sterilant for rapeseed prepared by the present invention has a higher release rate in a slightly alkaline environment. Thus, it can be known that the chemical male-sterilant for rapeseed obtained in the present invention has pH responsiveness and can act on the male reproductive organs of rapeseed as much as possible after application.

[0034] II. Field experiment: Using Zhongshuang 11 as the female parent and Zhongyouza 19 as the male parent, a field experiment was carried out. Sowing was carried out on September 30, 2023. The experiment was set with three biological replicates. The plot scale was a 6-row plot. The male parent was planted in the first and sixth rows, and the female parent was planted in the middle four rows. The plot length was 3 m, the row spacing was 0.5 m, and 20 plants were fixed in each row. Field management was carried out according to the conventional method.

[0035] The chemical male-sterilants for rapeseed obtained in Examples 7-9 and Comparative Examples 1-2 were used for the experiment. Taking Example 7 as an example, the chemical male-sterilant obtained in Example 7 was mixed with the female parent seeds at 0.5 kg / mu, 1.0 kg / mu, and 1.5 kg / mu respectively and sown simultaneously, while the male parent was not applied. The above application rates were denoted as Example 7-1, Example 7-2, and Example 7-3 respectively. The treatments of Example 8 and Example 9 were the same as above. The application rate of Comparative Example 1 was 20 g / mu, and it was applied by diluting with 50 kg of water when used. The application rate of Comparative Example 2 was 3 g / mu, and it was applied by diluting with 1 kg of water when used. Comparative Example 1 and Comparative Example 2 were sprayed when the length of the main inflorescence flower buds of 70% of the female parent plants was 1-2 mm, and attention was paid to shielding the adjacent male parent. Another control group was set, and the female parent of the control group was not treated.

[0036] At the initial flowering stage of rapeseed, 10 plants were continuously selected and tagged starting from the second plant in the second row of the female parent, and the whole plant was bagged for self-pollination for subsequent seed testing. At the full flowering stage of rapeseed, at 10:00, 3 flowers that opened on the same day were picked from the top of the main inflorescence of the selected 10 plants, and the pistil length, stamen length, petal length, and petal width were counted. Before harvesting, the plant height, main inflorescence length, silique length, number of primary branches, number of seeds per silique, and total number of seeds of the 10 plants selected for each replicate were investigated, and the relative seed setting rate (total number of seeds per plant of the treatment / total number of seeds per plant of the control) was calculated. At the time of harvesting, each plot was harvested separately, and the field yield was calculated by drying and weighing the grains actually harvested from each plot.

[0037] After treatment with different chemical male-sterilants for rapeseed, the results of pistil length, stamen length, petal length, and petal width are as Figure 2As shown, by Figure 2 it can be seen that the rapeseed chemical male sterilant obtained in Examples 7-9 has the greatest effect on stamens at 1.5 kg / mu, and there are obvious differences in stamen length and petal conditions compared with the control group.

[0038] After treatment with different rapeseed chemical male sterilants, the results of plant height, main inflorescence length, silique length, number of primary branches, number of seeds per silique, and total number of seeds are respectively as Figure 3 , Figure 4 , Figure 5 shown. By Figures 3 - 5 it can be seen that the rapeseed chemical male sterilants in Examples 7-9 and Comparative Examples 1-2 all have different degrees of inhibition on plant height, main inflorescence length, silique length, etc. After calculation, the relative seed-setting rates of Example 7-1, Example 7-2, Example 7-3, Example 8-1, Example 8-2, Example 8-3, Example 9-1, Example 9-2, Example 9-3, Comparative Example 1, and Comparative Example 2 are 10.0%, 8.4%, 6.5%, 9.8%, 8.3%, 6.6%, 9.7%, 8.5%, 6.6%, 8.0%, and 7.8% respectively. When the seed-setting rate of the female parent ≤ 10%, it indicates that the male sterilant treatment is successful, the emasculation is complete, and the purity of the hybrid can be better guaranteed. Thus, it can be seen that the rapeseed chemical male sterilant prepared by the present invention all shows good male sterilization effects at the experimental doses.

[0039] After the field experiment, the results of yield and relative yield after treatment with different rapeseed chemical male sterilants are as Figure 6 shown. By Figure 6 it can be seen that for the rapeseed chemical male sterilant obtained in Examples 7-9, with the increase of the application dose, the yield will be affected to a certain extent. After application at 1.5 kg / mu, its relative yield is 68.74%, and this value is still higher than the corresponding values of Comparative Example 1 and Comparative Example 2. Thus, it can be seen that by applying the rapeseed chemical male sterilant obtained by the present invention at an appropriate dose, better economic benefits can be obtained.

[0040] The above are only several embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention is disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, making some changes or modifications using the above-disclosed technical content is equivalent to equivalent implementation cases, and all belong to the scope of protection of the technical solution of the present invention.

Claims

1. A chemical maleicide for rapeseed, characterized in that: The invention comprises the following raw materials in parts by weight: 8-12 parts of compounded chemical-killing agent nanoparticles and 3-5 parts of pH-responsive compound.

2. The rapeseed chemical maleicide according to claim 1, characterized in that: The preparation method of the composite chemical killing agent nanoparticles is as follows: L1. Dissolve hydroxyethyl starch in water to obtain a hydroxyethyl starch solution with a mass percentage concentration of 8-10%, weigh the hydroxyethyl starch solution and the potassium periodate solution according to a volume ratio of 1:0.8-1, adjust the pH, stir in a dark environment, and obtain liquid A after completion; L2. Weigh the liquid A obtained in step L1 and anhydrous ethanol in a volume ratio of 1:2-3, let stand at room temperature, dialyze using a dialysis bag, collect the material in the dialysis bag, and obtain material A after vacuum freeze-drying; L3. Weigh the substance A obtained in step L2 and oleic acid according to a mass volume ratio of 1-2g: 5-6mL, heat, stir, dialyze using a dialysis bag, and then freeze-dry in vacuum to obtain substance B; L4. Dissolve paclobutrazol and oxasulfuron in acetone to obtain liquid B, add substance B obtained in step L3 to liquid B, perform ultrasonic treatment, and then spray dry to obtain composite chemical pesticide nanoparticles.

3. The rapeseed chemical maleicide according to claim 2, characterized in that: The mass percentage concentration of the potassium periodate solution in step L1 is 6-8%.

4. The rapeseed chemical maleicide according to claim 3, characterized in that: The amount of substance B added in step L4 is 6-8 g / L.

5. The rapeseed chemical maleicide according to claim 4, characterized in that: The preparation method of the pH responsive complex is as follows: S1. Weigh all-silica mesoporous molecular sieve and toluene according to a mass volume ratio of 200-240 mg: 30-40 mL, stir until uniformly dispersed, and obtain liquid C. Weigh liquid C and 3-aminopropyl (diethoxy) methyl silane according to a volume ratio of 8-10: 1, heat, stir, and naturally cool to room temperature after the end, and wash thoroughly with methanol. The obtained product is substance C after drying; S2. Weigh the substance C, dimethylformamide and polyethyl acrylate obtained in step S1 according to the mass volume ratio of 100-120 mg: 40-50 mL: 200-300 mg, heat, stir and centrifuge to obtain a precipitate; S3. The precipitate obtained in step S2 is washed with methanol and then dried to obtain a pH-responsive complex.

6. A method for preparing the rapeseed chemical maleicide according to any one of claims 1 to 5, characterized in that: The composite chemical maleicide nanoparticles are added to methanol, stirred until uniformly dispersed, and then the pH response complex is added, and the stirring treatment is continued at the same speed. After the stirring treatment is completed, the methanol is removed by rotary evaporation to obtain the rapeseed chemical maleicide of the present invention.

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