Application of rose in preparation of nano-selenium

Abstract

This invention provides the application of roses in the preparation of nano-selenium, relating to the field of functional materials technology. This application is the first to use roses to prepare nano-selenium, providing a new and excellent matrix and a novel method for preparing nano-selenium. The method used in this application produces more stable nano-selenium, with controllable size and morphology, while maintaining the material's bioactivity. Because roses themselves have strong antioxidant capabilities, the antioxidant capacity of the modified nano-selenium is also enhanced. Furthermore, this nano-selenium also inhibits the activity of plant pathogens, prevents plant diseases, and promotes plant growth, providing a new functional material for the field of plant protection.

Description

Technical Field

[0001] This application relates to the field of functional materials technology, and in particular to the application of rose in the preparation of nano-selenium. Background Technology

[0002] There are many methods for synthesizing nano-selenium (SeNPs), mainly including physical, chemical, and biological methods. Physical methods are simple and rapid, but require sophisticated equipment and are difficult to control in terms of particle size. In biosynthesis, the microbial method requires aseptic operation and stringent conditions, and the tolerance of a single microorganism to selenium oxides is limited. Chemical methods for preparing SeNPs typically use selenium sources such as sodium selenite, selenite acid, and selenium dioxide as oxidants, and chemical reagents such as ascorbic acid, hydrazine, and sodium thiosulfate as reducing agents, where the oxidant and reducing agent combine to undergo a redox reaction. This method is simple to operate and allows for controllable particle size, crystal form, and shape, but its stability, biocompatibility, and bioactivity are significantly reduced. To ensure the stability of the prepared SeNPs products, additional stabilizers or modifiers such as sugars, proteins, lipids, and polymers are needed. Modifiers used on the surface of SeNPs mainly include polymers, sugars, proteins, lipids, and even drugs. They are characterized by multiple branches, a large number of hydroxyl or amino groups, and the ability to form stable electrostatic interactions with the surface of SeNPs. This can prevent the aggregation of selenium particles and ensure the high dispersibility and stability of SeNPs.

[0003] Some studies have attempted to modify SeNPs using plant extracts as stabilizers, including peanut meal, chili leaves, hawthorn, and aloe vera. However, these studies still lack systematicity and the effectiveness needs improvement. There are currently no precedents for modifying SeNPs with rose extract. Summary of the Invention

[0004] The purpose of this invention is to provide a method for modifying nano-selenium with rose as a stabilizer and the nano-selenium obtained therefrom. This method has higher stability, and the size and morphology of the nano-selenium can be controlled, while ensuring the activity of the material, thus obtaining stable and functional nano-selenium.

[0005] On the one hand, this application provides the application of rose in the preparation of nano-selenium.

[0006] Furthermore, the rose may be one or more of the following: rose petals, rose stems, rose leaves, rose roots, or rose fruits.

[0007] In a preferred embodiment, the rose is a rose flower, more preferably, a rose petal.

[0008] The rose variety does not affect the technical effect of this application. Therefore, this application does not impose too many restrictions on the rose variety. Those skilled in the art can choose a suitable rose variety for experimentation.

[0009] On the other hand, this application also provides a method for preparing nano-selenium using roses, the method comprising the following steps:

[0010] Step 1: Prepare rose extract;

[0011] Step 2: React the rose extract with a selenium-based oxidant and an antioxidant.

[0012] Further, the method for preparing the rose extract includes: obtaining a rose extract by water extraction; preferably, the method further includes a step of freeze-drying the rose extract; preferably, in step two, the mass ratio of the rose extract to the selenium source oxidant is (1-5):1; more preferably, in step two, the mass ratio of the rose extract to the selenium source oxidant is 1.25:1.

[0013] The mass ratio of rose extract to selenium-based oxidant can be any value among 1:1, 1.25:1, 2:1, 3:1, 4:1, and 5:1.

[0014] Preferably, the method for preparing the rose extract includes: placing roses in boiling water (100°C) for 10-60 minutes, allowing them to stand, filtering the supernatant and freeze-drying to obtain the rose extract.

[0015] Rose extract can be obtained by conventional water extraction, and this application does not specify the steps involved.

[0016] Furthermore, the selenium source oxidant is selected from one or more of sodium selenite, selenite, and selenium dioxide.

[0017] Preferably, the selenium source oxidant is sodium selenite.

[0018] Further, the antioxidant is selected from one or more of ascorbic acid, hydrazine, and sodium thiosulfate; preferably, the mass ratio of the antioxidant to the selenium source oxidant is (2-5):1; more preferably, the mass ratio of the antioxidant to the selenium source oxidant is 3:1.

[0019] The mass ratio of the antioxidant to the selenium-based oxidant can be any value among 2:1, 3:1, 4:1, and 5:1.

[0020] Preferably, the antioxidant is ascorbic acid.

[0021] Furthermore, the reaction temperature is 10℃-80℃.

[0022] The reaction temperature can be selected from any of the following: 10℃, 40℃, 60℃, 70℃, and 80℃.

[0023] Furthermore, the reaction time is 10-60 min.

[0024] The reaction time can be selected from any one of 10 min, 20 min, 30 min, 40 min, 50 min, or 60 min.

[0025] In a preferred embodiment, a method for preparing selenium nanoparticles using rose petals includes the following steps:

[0026] Step 1: Place rose petals in boiling water at 100℃ at a ratio of 1:(20-30)g / mL and boil for 10-60 minutes with stirring at 100-600rpm. Let stand, filter the supernatant and freeze-dry for 1-10 hours to obtain rose petal extract.

[0027] Step 2: Stir the rose extract with selenium source oxidant and antioxidant to react at a temperature of 10℃-80℃ for 10-60 min. After the reaction is completed, freeze dry to obtain nano-selenium. The mass ratio of rose extract, selenium source oxidant and antioxidant is (1-5):1:(2-5).

[0028] The selenium content in the nano-selenium is greater than 500 mg / L; preferably, it is greater than 700 mg / L.

[0029] The selenium content in the nano-selenium obtained by the method can reach 712 mg / L.

[0030] On the other hand, this application also provides nano-selenium prepared by the method, wherein the nano-selenium has a particle size of 90-360 nm; preferably, 90-110 nm; more preferably, 90-100 nm. The potential of the nano-selenium is -50 mV to -19 mV; preferably, -50 to -30 mV.

[0031] Preferably, the nano-selenium has a spherical crystal structure and good stability, including pH stability and ionic stability. The nano-selenium system remains stable for extended periods at room temperature. It exhibits good stability within a pH range of 4-10, with no significant changes in particle size or potential, demonstrating a certain pH buffering capacity. Even after adding NaCl or KCl, when the ion concentration is less than 10 mmol / L, the nano-selenium system remains clear, with no significant changes in particle size or potential.

[0032] On the other hand, this application also provides a fertilizer containing the aforementioned nano-selenium.

[0033] It is understood that the fertilizer products of this application may also contain excipients, which may be appropriate solvents, solubilizers, co-solvents, emulsifiers, colorants, binders, disintegrants, fillers, lubricants, wetting agents, stabilizers, flow aids, preservatives, suspending agents, coating materials, fragrances, anti-adhesion agents, integrators, pH adjusters, plasticizers, surfactants, release inhibitors, and other known excipients available for fertilizer products.

[0034] The fertilizer described in this application can be prepared using common methods.

[0035] Preferably, the fertilizer is tomato fertilizer.

[0036] Preferably, the fertilizer is an antibacterial fertilizer; the antibacterial properties include inhibition of tomato gray mold, grape white rot, wheat stem base pathogen, wheat root rot pathogen, and / or wheat scab; more preferably, the tomato gray mold is *Botrytis cinerea*; more preferably, the grape white rot pathogen is *Coniella diplodiella*; more preferably, the wheat stem base pathogen is *Fusarium graminearum*; more preferably, the wheat root rot pathogen is *Bipolaris sorokinina*; more preferably, the wheat scab pathogen is *Fusarium graminearum*.

[0037] On the other hand, this application also provides the application of the nano-selenium in any one or more of A1)-A4):

[0038] A1) Inhibits the activity of plant pathogens; preferably, the plant pathogens include *Botrytis cinerea*, *Botrytis cinerea*, *Coniella diplodiella*, *Fusarium graminearum*, and / or *Fusarium graminearum*; more preferably, the *Botrytis cinerea* is *Botrytis cinerea*; more preferably, the *Botrytis cinerea* is *Coniella diplodiella*; more preferably, the *Fusarium graminearum* is *Fusarium graminearum*; more preferably, the *Fusarium graminearum* is *Bipolaris sorokinina*; more preferably, the *Fusarium graminearum* is *Fusarium graminearum*.

[0039] A2) Prevention and control of plant diseases; preferably, the plant diseases include tomato gray mold, grape white rot, wheat stem base disease, wheat root rot and / or wheat scab;

[0040] A3) Promote plant growth; preferably, promoting tomato growth includes improving the plant's antioxidant capacity, increasing the plant's peroxidase (POD) content, increasing the plant's superoxide dismutase (SOD) content, increasing the plant's chlorophyll content, increasing the plant's amino acid content, increasing the plant's height, and / or increasing the plant's biomass; preferably, the plant is tomato; preferably, the chlorophyll includes chlorophyll a and chlorophyll b;

[0041] A4) Increasing the selenium content of plants and / or preparing selenium-enriched products; preferably, the plant is tomato; preferably, the selenium content of the product or plant is 0.02-1.0 mg / kg; more preferably, the selenium content of the product or plant is 0.4-1.0 mg / kg.

[0042] Among these, improving antioxidant capacity is achieved by increasing the content of plant peroxidase (POD) and superoxide dismutase (SOD).

[0043] In a preferred embodiment, the concentration of the nano-selenium is 20-70 mg / L.

[0044] Those skilled in the art can adjust the concentration of nano-selenium according to the actual situation, and this application does not make specific limitations on this.

[0045] The present invention has the following beneficial effects:

[0046] This application is the first to use roses to prepare nano-selenium, providing a new and excellent matrix for the preparation process of nano-selenium and a new method for preparing nano-selenium.

[0047] The method described in this application produces more stable nano-selenium, with controllable size and morphology, while maintaining the material's bioactivity. Since rose itself has strong antioxidant capabilities, the modified nano-selenium also exhibits enhanced antioxidant capacity. Furthermore, this nano-selenium also inhibits the activity of plant pathogens, prevents plant diseases, and promotes plant growth, providing a novel functional material for the field of plant protection. Attached Figure Description

[0048] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0049] Figure 1 A statistical graph showing the effect of the ratio of selenium precursor to antioxidant (reducing agent) on the particle size of nano-selenium;

[0050] Figure 2 This is a statistical graph showing the effect of reaction temperature on the size of nano-selenium particles.

[0051] Figure 3 A statistical chart showing the effect of rose freeze-dried powder addition on the size of nano-selenium particles.

[0052] Figure 4 SEM image of the nano-selenium prepared by the method in Example 2;

[0053] Figure 5 The particle size distribution of the selenium nanoparticles prepared by the method in Example 2 is shown in the diagram.

[0054] Figure 6 The potential map of nano-selenium prepared by the method in Example 2;

[0055] Figure 7 Figure 1 shows the changes in the size and potential of selenium nanoparticles at different pH values.

[0056] Figure 8 The graph shows the changes in the size and potential of nano-selenium particles in NaCl at different concentrations.

[0057] Figure 9 The graph shows the changes in the size and potential of selenium nanoparticles in KCl at different concentrations.

[0058] Figure 10 The graph shows the changes in the size and potential of selenium nanoparticles in CaCl2 at different concentrations.

[0059] Figure 11 Here is a SEM image of the selenium nanoparticles prepared by the method in Comparative Example 1;

[0060] Figure 12 The diagram shows the stability experiment of the selenium nanoparticles prepared by the methods in Examples 2 and 3. The left side shows the selenium nanoparticles prepared by the method in Example 2, and the right side shows the selenium nanoparticles prepared by the method in Example 3.

[0061] Figure 13 Schematic diagram showing the antibacterial activity of different antibacterial components against tomato gray mold;

[0062] Figure 14 A standard curve diagram of nano-selenium against tomato gray mold;

[0063] Figure 15 Schematic diagram showing the antibacterial activity of different concentrations of nano-selenium against tomato gray mold;

[0064] Figure 16 A schematic diagram illustrating the antibacterial activity of nano-selenium against grape white rot fungus, wheat stem base fungus, wheat root rot fungus, and wheat scab fungus.

[0065] Figure 17 A statistical chart of free radical scavenging rates;

[0066] Figure 18 A statistical chart of POD content in tomatoes;

[0067] Figure 19 A statistical chart of SOD content in tomatoes;

[0068] Figure 20 A statistical chart of tomato chlorophyll content;

[0069] Figure 21 A statistical chart of amino acid content in tomatoes;

[0070] Figure 22 A statistical chart of tomato height;

[0071] Figure 23 This is a graph showing the biomass of tomatoes. Detailed Implementation

[0072] To more clearly illustrate the overall concept of this application, a detailed description is provided below with reference to the accompanying drawings and embodiments. Numerous specific details are set forth in the following description to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with the invention.

[0073] Before further describing specific embodiments of the present invention, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention. Test methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the respective manufacturers.

[0074] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0075] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the present invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. In addition to the specific methods, apparatus, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description of this invention, any prior art methods, apparatus, and materials similar to or equivalent to those described, apparatus, and materials in the embodiments of this invention may be used to implement the present invention.

[0076] Unless otherwise specified, in the following embodiments, reagents or instruments whose manufacturers are not indicated are all conventional products that can be purchased commercially.

[0077] Unless otherwise stated, the experimental methods, detection methods, and preparation methods disclosed in this invention all employ conventional techniques from the fields of microbiology, biochemistry, analytical chemistry, botany, agronomy, and related fields.

[0078] In addition, the "water" mentioned in this invention includes any feasible water that can be used in the art, such as deionized water, distilled water, ion-exchanged water, double-distilled water, high-purity water, and purified water.

[0079] In the following examples, unless otherwise specified, % means wt%, i.e., weight percentage.

[0080] Example 1: Optimization of preparation conditions for nano-selenium

[0081] This embodiment provides a method for preparing nano-selenium, as detailed below:

[0082] Step 1: Preparation of freeze-dried rose powder:

[0083] Using a 1L beaker, place 500mL of water in a magnetic stirrer at 400rpm and 100℃. After heating, boil 20g of dried rose petals in the water for 30 minutes and let stand for 4 hours. Filter the supernatant twice with filter paper and then freeze-dry for 8 hours to obtain freeze-dried rose powder.

[0084] Step 2: Preparation of nano-selenium:

[0085] 0.08g of freeze-dried rose powder was placed in 100mL of double-distilled water at 40℃, and sodium selenite and ascorbic acid (40mg sodium selenite and 120mg ascorbic acid) were added in a mass ratio of 1:3. The mixture was stirred for 30min and then freeze-dried to obtain nano-selenium particles (SeNPs).

[0086] Based on this, the effects of antioxidant dosage, preparation temperature, and rose freeze-dried powder dosage on the particle size and potential of selenium nanoparticles were optimized. The particle size and potential of the selenium nanoparticles were determined using dynamic light scattering (DLS) and SEM.

[0087] (1) Optimization of antioxidant addition amount

[0088] Nano-selenium particles were prepared by adding different amounts of antioxidant (ascorbic acid), such as 0.04g, 0.12g, and 1.2g.

[0089] The preparation method of nano-selenium includes: placing 0.08g of freeze-dried rose powder in 100mL of double-distilled water, adding 0.04g of sodium selenite and 0.04g, 0.12g, and 1.2g of ascorbic acid, stirring for 30min, and freeze-drying to obtain nano-selenium particles. The remaining steps are the same as described above, and the results are shown in Table 1. A graph is plotted from Table 1 to obtain... Figure 1 .

[0090] Table 1

[0091] Sodium selenite (g) Ascorbic acid (g) Sodium selenite: ascorbic acid Average particle size (nm) Potential (mV) 0.04 0.04 1:1 355 -19 0.04 0.12 1:3 167 -20 0.04 1.2 1:30 188 -21

[0092] From Table 1 and Figure 1 The results show that the amount of antioxidant added has a certain influence on the particle size of the selenium nanoparticles. The smallest particle size, reaching 167 nm, is achieved when the amount of antioxidant added is 0.12 g. At this point, the mass ratio of antioxidant (ascorbic acid) to sodium selenite is 3:1.

[0093] (2) Optimization of preparation temperature

[0094] Under the optimized conditions in step (1), nano-selenium particles were prepared at different temperatures.

[0095] The preparation method of nano-selenium includes: placing 0.08g of freeze-dried rose powder in 100mL of double-distilled water at temperatures of 10℃, 40℃, 60℃, 70℃, or 80℃; adding sodium selenite and ascorbic acid in a mass ratio of 1:3; stirring for 30min; and freeze-drying to obtain nano-selenium particles. The remaining steps are as described above. The results are shown in Table 2. A graph is plotted from Table 2 to obtain... Figure 2 .

[0096] Table 2

[0097] Temperature (°C) Average particle size (nm) Potential (mV) 10 206 -19 40 167 -22 60 142 -19 70 109 -22 80 115 -23

[0098] From Table 2 and Figure 2 The results show that the reaction temperature has a certain influence on the particle size of the selenium nanoparticles. The particle size is the smallest at a temperature of 70℃, reaching 109nm.

[0099] (3) Optimization of freeze-dried powder addition amount

[0100] Under the optimized conditions in step (2), nano-selenium particles were prepared by adding different amounts of freeze-dried rose powder.

[0101] The preparation method of nano-selenium includes: placing 0.02g, 0.05g, 0.08g, 0.1g, 0.5g, and 1g of freeze-dried rose powder into 100mL of double-distilled water at 70℃, adding sodium selenite and ascorbic acid in a mass ratio of 1:3, stirring for 30min, and freeze-drying to obtain nano-selenium particles. The remaining steps are the same as described above. The results are shown in Table 3. A graph is plotted from Table 3 to obtain... Figure 3 .

[0102] Table 3

[0103] Sample (g) Average particle size (nm) Potential (mV) 0.02 119 -40.4 0.05 95 -42.7 0.08 113 -28.4 0.1 114 -25.1 0.5 138 -17.9 1 143 -17.0

[0104] From Table 3 and Figure 3 The results show that the amount of freeze-dried rose powder added has a certain influence on the particle size of nano-selenium particles. When the amount of freeze-dried rose powder added is 0.05g, the particle size is the smallest, reaching 95nm.

[0105] Example 2

[0106] A preferred method for modifying nano-selenium using rose extract as a stabilizer, according to Example 1, includes:

[0107] Step 1: Preparation of freeze-dried rose powder:

[0108] Using a 1L beaker, place 500mL of water in a magnetic stirrer at 400rpm and 100℃. After heating, boil 20g of dried rose petals in the water for 30 minutes and let stand for 4 hours. Filter the supernatant twice with filter paper and then freeze-dry for 8 hours to obtain freeze-dried rose powder.

[0109] Step 2: Preparation of nano-selenium:

[0110] 0.05g of freeze-dried rose powder was placed in 100mL of double-distilled water at 70℃, and sodium selenite and ascorbic acid (40mg sodium selenite and 120mg ascorbic acid) were added in a mass ratio of 1:3. The mixture was stirred for 30min and then freeze-dried to obtain nano-selenium particles (SeNPs).

[0111] Scanning electron microscopy (SEM) was used to observe nano-selenium, and the results are as follows: Figure 4 As shown in the SEM image, the selenium nanoparticles obtained in Example 2 have a stable spherical structure with a particle size of 104 nm. The particle size, potential, and morphology of the selenium nanoparticles were measured using dynamic light scattering (DLS) and SEM, ultimately yielding selenium nanoparticles with a particle size of approximately 90-100 nm. Figure 5 The potential is around -50 to -30mV. Figure 6 ).

[0112] In this embodiment, stability tests were conducted on the selenium nanoparticles prepared by the preferred method, particularly regarding the effects of pH value and different ions on the stability of the selenium nanoparticles.

[0113] 1. Effect of pH value on the stability of selenium nanoparticles

[0114] The specific testing method was as follows: The pH of the selenium nanoparticle suspension was adjusted using formic acid and sodium hydroxide, respectively. To reduce experimental variability, the particle size and potential were measured within 1 minute of processing. The results are shown in Table 4, and the results were obtained by plotting Table 4. Figure 7 .

[0115] Table 4

[0116] pH Average particle size (nm) Potential (mV) 2 142 -5 4 110 -32 6 109 -31 8 109 -32 10 109 -32

[0117] As shown in Table 4 and Figure 7 As shown, pH significantly affects the stability of selenium nanoparticles by altering their surface electrochemical properties and particle size. The effect on the stability of selenium nanoparticles is most significant when the pH is 2, with a corresponding particle size of 142 nm and a zeta potential of -5 mV.

[0118] This is because freeze-dried roses contain various components, including soluble sugars and polyphenols, which are rich in functional groups such as carboxyl, amino, and hydroxyl groups. These groups dissociate in aqueous solution, generating negative charges. Changes in pH alter these surface charges, leading to the formation and breaking of chemical bonds between selenium nanoparticles, thus affecting their aggregation or deaggregation behavior and ultimately changing key stability parameters (such as zeta potential and particle size). Notably, in this embodiment, the selenium nanoparticles exhibited good stability within a pH range of 4-10, with minimal changes in particle size and zeta potential, demonstrating strong pH tolerance. This phenomenon suggests that selenium nanoparticles prepared using roses as a stabilizer may possess a certain pH buffering capacity, helping to maintain a relatively stable particle size distribution in different pH environments.

[0119] 2. Effect of ion type on the stability of selenium nanoparticles

[0120] The type and concentration of ions are key factors determining the stability of selenium nanoparticles in solution. To investigate these effects, different concentrations of NaCl, KCl, and CaCl2 were added to the selenium nanoparticle suspension for 1 min, and the changes in colloidal properties were evaluated by visual observation, particle size measurement, and zeta potential analysis.

[0121] The results are shown in Table 5. The graphs obtained from Table 5 are as follows. Figure 8-10 .

[0122] Table 5

[0123] ion Average particle size (nm) Potential (mV) 5mmol / L NaCl 108 -28 10 mmol / L NaCl 107 -25 100mmol / L NaCl 108 -18 200 mmol / L NaCl 132 -13 5mmol / L KCl 146 -27 10 mmol / L KCl 106 -27 100mmol / L KCl 150 -14 200mmol / L KCl 191 -14 <![CDATA[5mmol / L CaCl2]]> 144 -12 <![CDATA[10mmol / L CaCl2]]> 180 -9 <![CDATA[100mmol / L CaCl2]]> 161 -8 <![CDATA[200mmol / L CaCl2]]> 182 -2

[0124] From Table 5 and Figure 8-10It can be seen that the addition of NaCl and KCl did not cause visible precipitation in the suspension, which remained clear. However, as the concentration of NaCl increased, the particle size gradually increased and the absolute value of the zeta potential decreased, indicating a change in the colloidal properties, but no aggregation or precipitation was induced. The effect of KCl was more significant than that of NaCl: at a KCl concentration of 10 mmol / L, the zeta potential did not change compared with that at 5 mmol / L.

[0125] It should be noted that CaCl2 showed the strongest effect on destroying stability, immediately inducing visible flocculation and significantly reducing the absolute value of the zeta potential. When the CaCl2 concentration was 200 mmol / L, the particle size increased to 182 nm, indicating a significant decrease in dispersibility and stability. These results clearly demonstrated that divalent Ca 2+ ions had a stronger electrostatic shielding effect than monovalent Na + and K + ions, making selenium nanoparticles particularly sensitive to polyvalent cations, and their stability followed the rule of NaCl < KCl < CaCl2. These findings highlight the importance of controlling the ionic environment in practical applications to maintain the colloidal stability of selenium nanoparticles.

[0126] Comparative Example 1

[0127] In this comparative example, a kind of nano selenium particles (SeNPs) prepared by chitosan oligosaccharide was provided.

[0128] Specifically, 400 mg of chitosan oligosaccharide was mixed with 100 mL of ultrapure water, 80 mg of sodium selenite and 240 mg of ascorbic acid were added successively, and stirred for 30 min to obtain nano selenium particles (SeNPs).

[0129] The particle size, potential and appearance morphology of nano selenium were measured by dynamic light scattering (DLS) and SEM. The results were as Figure 11 shown. The SEM image showed that the nano selenium particles obtained in Comparative Example 1 had poor dispersion effect, aggregation phenomenon, and relatively large particle size, ranging from 132 nm to 245 nm, with an average of 214 nm, and the potential was 1.25 mV.

[0130] Example 3

[0131] The difference between this example and Example 2 was only that rose freeze-dried powder was not added.

[0132] Specifically, 100 mL of double-distilled water at a temperature of 70 °C was taken, sodium selenite and ascorbic acid with a mass ratio of 1:3 (40 mg of sodium selenite and 120 mg of ascorbic acid) were added, stirred for 30 min, and freeze-dried to obtain nano selenium particles (SeNPs).

[0133] The particle size, potential, and morphology of the nano-selenium were determined by dynamic light scattering (DLS) and SEM. The results showed that the potential was 0.21 mV and the average particle size was 3920 nm.

[0134] Furthermore, in this embodiment, the stability of the selenium nanoparticles prepared by the methods of Example 3 and Example 2 was tested. The test method involved placing the selenium nanoparticles prepared by the methods of Example 3 and Example 2 at room temperature for 5 minutes and then observing the system conditions. The results are as follows: Figure 12 As shown (left: nano-selenium prepared by the method of Example 2; right: nano-selenium prepared by the method of Example 3), it can be seen that the nano-selenium particles prepared by the method of Example 3 without the addition of freeze-dried rose powder as a stabilizer rapidly agglomerate and settle. In contrast, the nano-selenium particle system prepared by the method of Example 2 is more stable, has higher activity, and can be stored for a longer period.

[0135] In summary, rose petals, rich in amino acids, polyphenols, and sugars, can serve as natural templates. Therefore, the freeze-dried rose powder template, rich in hydroxyl, carboxyl, amino, carbonyl, and hydrophobic regions, can bind to elemental selenium through electrostatic forces, secondary bonds, and hydrophobic interactions. This effectively prevents selenium particles from binding and agglomerating, slowing down and controlling particle growth, thereby forming stable, dispersed nano-selenium particles and a stable nano-selenium particle system.

[0136] Example 4

[0137] The only difference between this embodiment and Embodiment 2 is that the freeze-drying process is not performed.

[0138] Step 1: Preparation of rose extract:

[0139] Using a 1L beaker, place 500mL of water in a magnetic stirrer at 400 rpm and 100℃. After heating, place 20g of dried rose petals in the water and boil for 30 minutes, then let stand for 4 hours. Filter the supernatant twice with filter paper to obtain rose extract.

[0140] Step 2: Preparation of nano-selenium:

[0141] 0.05g of rose extract was placed in 100mL of double-distilled water at 70℃, and sodium selenite and ascorbic acid (40mg sodium selenite and 120mg ascorbic acid) were added in a mass ratio of 1:3. The mixture was stirred for 30min and then freeze-dried to obtain nano-selenium particles (SeNPs).

[0142] The particle size, potential, and morphology of the selenium nanoparticles were determined by dynamic light scattering (DLS) and SEM. The results showed that the potential was -0.34 mV and the average particle size was 225 nm. This indicates that the selenium nanoparticles prepared by using rose extract as a stabilizer after freeze-drying exhibited a smaller particle size.

[0143] Example 5: Antibacterial activity of nano-selenium against plant pathogens

[0144] In this embodiment, nano-selenium prepared by the preferred method of Example 2, Example 3, and Comparative Example 1 were used as samples. The differences between nano-selenium and commonly used fungicides iprodione and boscalid were compared against tomato gray mold, and the EC50 of nano-selenium against tomato gray mold was determined. Then, the antifungal activity of nano-selenium against grape white rot fungus, wheat stem rot fungus, wheat root rot fungus, and wheat scab fungus was determined.

[0145] 1. Experiment on the inhibitory rate of nano-selenium against gray mold in tomatoes

[0146] In this embodiment, conventional laboratory treatment methods were used to conduct the antibacterial rate experiment:

[0147] (1) Chemical treatment

[0148] According to the experimental treatment, 90 mL of PDA medium was placed in an Erlenmeyer flask and autoclaved for later use. Before the drug treatment, the pre-sterilized PDA medium was melted. Under aseptic conditions, a quantitative amount of the drug solution was taken and added to the PDA medium cooled to 50℃-60℃, along with 2-3 drops of lactic acid. After mixing, the mixture was poured into four 90 mm diameter petri dishes to prepare drug-containing plates of the corresponding concentrations (low concentration 1 mg / L, high concentration 10 mg / L). A blank control without the drug was set up, and iprodione and boscalid were used as positive controls.

[0149] (2) Vaccination

[0150] Under aseptic conditions, using a 5mm diameter sterile punch, cut a mycelial cake from the outer edge of the pathogen colony cultured in PDA medium. Inoculate the mycelial cake onto the center of a drug-containing plate with the mycelial side facing up, cover the plate, and incubate in an incubator at 27±1℃.

[0151] (3) Investigation

[0152] After culturing in a biological incubator at 27±1℃ for 48 hours (measurement can be made when the blank colony grows to about 3-4cm), measure the diameter of the colony with calipers. Measure the diameter of each colony vertically once using the cross-sectional method and take the average value.

[0153] The results are shown in Table 6 and Figure 13 As shown.

[0154] Table 6. Effects of nano-selenium on tomato gray mold, categorized by high and low concentrations.

[0155] sample Antibacterial rate (%) Example 2: SeNPs 10 mg / L 93 Example 2: SeNPs 1 mg / L 44 Comparative Example 1: SeNPs 10 mg / L 85 Comparative Example 1: SeNPs 1 mg / L 24 Iprodione 10 mg / L 98 Iprodione 1 mg / L 65 Cyclomethasone 10 mg / L 87 Cyclomethasone 1 mg / L 74

[0156] From Table 6 and Figure 13The results show that the SeNPs prepared by the method in Example 2 can achieve an inhibition rate of 93% against tomato gray mold, which means that the SeNPs prepared by the method in Example 2 have a high inhibitory effect on tomato gray mold and can effectively control the occurrence of tomato gray mold.

[0157] 2. EC50 calculation of SeNPs prepared by the method in Example 2 against tomato gray mold.

[0158] The specific method is as follows: with the logarithm of the drug concentration (mg / L) as the independent variable X and the probability of mycelial growth inhibition rate as the dependent variable Y, virulence regression equations are established respectively, and EC50 is calculated.

[0159] Standard curve such as Figure 14 As shown, the results are as follows Figure 15 As shown, the calculated EC50 of nano-selenium against tomato gray mold is 4.86 mg / L.

[0160] 3. The antibacterial activity of SeNPs prepared by the method in Example 2 against Grape white rot fungus, wheat stem base fungus, wheat root rot fungus, and wheat scab fungus.

[0161] The specific method is as follows: the steps of the antibacterial test are the same as those described in the experiment on the antibacterial rate of nano-selenium against tomato gray mold.

[0162] The results are as follows Figure 16 As shown, the nano-selenium prepared by the method in Example 2 has an inhibitory effect on grape white rot fungus, wheat stem base fungus, wheat root rot fungus and wheat scab fungus.

[0163] Example 6: Effects of nano-selenium on tomato growth

[0164] In this embodiment, the nano-selenium prepared by the preferred method of Example 2 and Comparative Example 1 was used as a sample and applied to tomatoes to investigate the effect of nano-selenium on tomato growth.

[0165] The specific method is as follows: Place the tomato seedlings under suitable conditions of temperature, humidity, and sunlight (16 hours of daytime, 25℃, 70% humidity; 8 hours of nighttime, 20℃, 50% humidity) for a period of time to stabilize their growth. Wrap the soil with aluminum foil to prevent excessive dripping of the pesticide solution into the soil. Dilute the SeNPs stock solution 10 times (70 mg / L) and 100 times (7 mg / L) with purified water as the high concentration (H) treatment group and the low concentration (L) treatment group, respectively. Pour the solution into a spray bottle and spray it evenly onto the leaves of the tomato seedlings until the solution is uniform. Repeat the spraying after 7 days. Samples are taken and measured approximately 2 hours after the solution dries.

[0166] The selenium nanoparticles synthesized using chitosan oligosaccharide are designated SeNPs1, and the selenium nanoparticles synthesized using the freeze-dried rose powder from Example 2 are designated SeNPs2. A graph is plotted, and the results are as follows: Figures 17-23 As shown.

[0167] Depend on Figure 17 The results showed that applying low concentrations (L) of the freeze-dried rose powder synthesized into nano-selenium in Example 2 could improve the antioxidant (free radical scavenging) ability of tomatoes.

[0168] Depend on Figure 18 The results showed that applying nano-selenium could increase the peroxidase (POD) content of tomatoes. Furthermore, the high-concentration (H) nano-selenium synthesized from freeze-dried rose powder in Example 2 exhibited a superior enhancing effect compared to nano-selenium synthesized using chitosan oligosaccharides.

[0169] Depend on Figure 19 The results showed that applying low concentrations of nano-selenium could increase the superoxide dismutase (SOD) content in tomatoes. Among them, the nano-selenium synthesized from rose freeze-dried powder in Example 2 was better than that synthesized from chitosan oligosaccharide. However, at high concentrations, the nano-selenium synthesized from chitosan oligosaccharide showed an inhibitory effect.

[0170] Depend on Figure 20 The results showed that applying the nano-selenium synthesized from the freeze-dried rose powder of Example 2 could increase the chlorophyll content of tomatoes.

[0171] Depend on Figure 21 The results showed that applying low concentrations of nano-selenium could increase the amino acid content of tomatoes, and the nano-selenium synthesized from rose freeze-dried powder in Example 2 had a superior enhancing effect compared to nano-selenium synthesized from chitosan oligosaccharide. However, high concentrations of nano-selenium exhibited an inhibitory effect.

[0172] Depend on Figure 22 The results showed that applying nano-selenium could increase the plant height of tomatoes, and the nano-selenium synthesized from rose freeze-dried powder in Example 2 had a better enhancing effect than the nano-selenium synthesized from chitosan oligosaccharide.

[0173] Depend on Figure 23 The results show that the application of nano-selenium can increase the biomass of tomatoes, and the nano-selenium synthesized from rose freeze-dried powder in Example 2 has a better enhancing effect than the nano-selenium synthesized from chitosan oligosaccharide.

[0174] In summary, the selenium nanoparticles (SeNPs2) prepared from freeze-dried rose powder showed a more significant effect on improving tomato growth than the selenium nanoparticles (SeNPs1) prepared from chitosan oligosaccharides. However, the effect of selenium nanoparticles exhibits a significant concentration-dependent effect. While SeNPs2 can enhance the antioxidant capacity and chlorophyll content of tomatoes, high concentrations may have negative effects, so dosage should be carefully monitored. Appropriate concentrations of selenium nanoparticles can promote tomato growth.

[0175] Example 7: Determination of Se content in nano-selenium stock solution and determination of selenium content in tomatoes.

[0176] In this embodiment, the nano-selenium prepared by the preferred method in Example 2 was used as the sample. The selenium content was determined by Standard Biotech Pharmaceutical Technology (Qingdao) Co., Ltd. The selenium content of the nano-selenium stock solution was 712 mg / L.

[0177] Furthermore, selenium was applied during the tomato seedling growth period. The specific fertilization method was as follows: The tomato seedlings were placed under suitable conditions of temperature, humidity, and sunlight (16 hours of daytime, 25℃, 70% humidity; 8 hours of nighttime, 20℃, 50% humidity) for a period of time to stabilize their growth. The soil was wrapped with aluminum foil to prevent excessive dripping of the solution. The SeNPs stock solution was diluted 10 times with purified water (70 mg / L), then poured into a spray bottle and sprayed evenly onto the tomato seedling leaves until the solution was evenly distributed. Spraying was repeated twice, with a 7-day interval between applications. A control group without spraying was used. After the results were obtained, the selenium content in the fruit was measured. 。

[0178] The average selenium content in the fruit during the fruiting period was 0.46 mg / kg, meeting the requirements for selenium-enriched products (0.02-1.0 mg / kg), while the selenium content in the blank control fruit was 0.0647 mg / kg. Therefore, it can be concluded that nano-selenium can effectively enrich tomatoes with selenium.

[0179] The above description is merely an embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for preparing nano-selenium using roses, characterized in that, The method includes the following steps: Step 1: Prepare rose extract; Step 2: React the rose extract with a selenium source oxidant and an antioxidant; the mass ratio of the rose extract to the selenium source oxidant is (1-5):1; the mass ratio of the antioxidant to the selenium source oxidant is (2-5):1; the reaction temperature is 10℃-80℃.

2. The method according to claim 1, characterized in that, The method for preparing the rose extract includes: obtaining rose extract by water extraction.

3. The method according to claim 2, characterized in that, The method also includes the step of freeze-drying the rose extract.

4. The method according to claim 1, characterized in that, In step two, the mass ratio of the rose extract to the selenium oxidant is 1.25:

1.

5. The method according to claim 1, characterized in that, The selenium source oxidant is selected from one or more of sodium selenite, selenite, and selenium dioxide.

6. The method according to claim 1, characterized in that, The antioxidant is selected from one or more of ascorbic acid, hydrazine, and sodium thiosulfate.

7. The method according to claim 1, characterized in that, The mass ratio of the antioxidant to the selenium-based oxidant is 3:

1.

8. The method according to claim 1, characterized in that, The reaction time is 10-60 min.

9. The nano-selenium prepared by the method according to any one of claims 1-8, characterized in that, The nano-selenium has a particle size of 90-360 nm.

10. The nano-selenium according to claim 9, characterized in that, The nano-selenium has a particle size of 90-110 nm.

11. A fertilizer containing nano-selenium as described in claim 9 or 10.

12. The application of the nano-selenium as described in claim 11 in any one or more of A1)-A4): A1) Inhibits the activity of plant pathogens; A2) Prevention and control of plant diseases; A3) Promotes plant growth; A4) Increase the selenium content of plants and / or prepare selenium-enriched products.

13. The application according to claim 12, characterized in that, The plant pathogens include tomato gray mold, grape white rot, wheat stem base rot, wheat root rot and / or wheat scab.

14. The application according to claim 13, characterized in that, The tomato gray mold pathogen is *Botrytis cinerea* (… Botrytis cinerea The grape white rot pathogen is *Cladosporium white rotense* ( ); Coniella diplodiella The wheat stem base pathogen is *Fusarium graminearum* (…). Fusarium pseudograminearum The wheat root rot pathogen is *Cyclocarya granatum* (…). Bipolaris sorokiniana The wheat scab pathogen is *Fusarium graminearum* ( ); Fusarium graminearum ).

15. The application according to claim 12, characterized in that, The plant diseases mentioned include tomato gray mold, grape white rot, wheat stem base disease, wheat root rot and / or wheat scab.

16. The application according to claim 12, characterized in that, The promotion of plant growth includes increasing the plant's antioxidant capacity, increasing the plant's peroxidase content, increasing the plant's superoxide dismutase content, increasing the plant's chlorophyll content, increasing the plant's amino acid content, increasing the plant's height, and / or increasing the plant's biomass.

17. The application according to claim 12, characterized in that, The plant in question is a tomato.

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