Application of rose in preparation of nano-selenium

Abstract

The invention provides application of roses in preparation of nano-selenium, and relates to the technical field of functional materials. According to the application, the rose is used for preparing the nano-selenium for the first time, a new excellent matrix is provided for a nano-selenium preparation process, and a new method for preparing the nano-selenium is provided. The nano-selenium prepared by the method disclosed by the invention is more stable, the prepared nano-selenium is controllable in size and form, meanwhile, the biological activity of the material is also maintained, and the antioxidant capacity of the nano-selenium modified by the rose is also enhanced due to the fact that the rose has relatively strong antioxidant capacity. Moreover, the nano-selenium also has the effects of inhibiting the activity of phytopathogen, preventing and treating plant diseases and promoting plant growth, and a novel functional material is provided for the field of plant protection.

Description

Technical Field

[0001] This application relates to the technical field of functional materials, and particularly to the application of roses in the preparation of nano-selenium. Background Art

[0002] There are many methods for synthesizing nano-selenium (SeNPs), mainly including physical methods, chemical methods, and biological methods, etc. Physical methods are simple and fast, but have high requirements for equipment conditions and are not easy to control the particle size. In the biological synthesis method, the preparation process of the microbial method requires aseptic operation, with harsh conditions, and the tolerance of a single microorganism to selenium oxides is limited. When preparing SeNPs by chemical methods, usually selenium sources such as sodium selenite, selenious acid, and selenium dioxide are used as oxidants, and chemical reagents such as ascorbic acid, hydrazine, and sodium thiosulfate are used as reducing agents. The oxidant and the reducing agent combine to undergo an oxidation-reduction reaction. This method for preparing nano-selenium has a simple operation process, and at the same time, its particle size, crystal form, and shape are controllable, but the stability, biocompatibility, and biological activity are greatly reduced. In order to make the prepared SeNPs product have stable performance, additional stabilizers or modifiers such as sugars, proteins, lipids, and polymer polymers need to be added. The modifiers used on the surface of SeNPs mainly include polymer polymers, sugars, proteins, lipids, and even drugs, etc., which have the characteristics of many branches, rich in a large number of hydroxyl or amino groups, and can have a stable electrostatic interaction with the surface of SeNPs, etc., and can prevent the mutual aggregation of selenium particles and ensure the high dispersibility and stability of SeNPs.

[0003] At present, some studies have attempted to use plant extracts as stabilizers to modify SeNPs, including plants such as peanut meal, pepper leaves, hawthorn, and aloe. However, the research still lacks systematicness and the effect needs to be improved. There is no precedent for modifying SeNPs with rose extracts at present. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for modifying nano-selenium with roses as a stabilizer and the obtained nano-selenium, which method has higher stability, and the size and morphology of the nano-selenium are controllable, and at the same time, the activity of the material can be ensured, and stable and functional nano-selenium can be prepared.

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

[0006] Furthermore, the rose can be one or more of rose flowers, rose stems, rose leaves, rose roots, or rose fruits.

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

[0008] The variety of roses has no impact on the technical effects of this application. Therefore, there are no excessive restrictions on the rose variety in this application, and those skilled in the art can select appropriate rose varieties for experiments.

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

[0010] Step 1: Prepare rose extract;

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

[0012] Further, the preparation method of the rose extract includes: obtaining a rose extract solution by water extraction method; preferably, the method further includes the step of freeze-drying the rose extract solution; preferably, in step 2, the mass ratio of the rose extract to the selenium source oxidant is (1-5):1; more preferably, in step 2, the mass ratio of the rose extract to the selenium source oxidant is 1.25:1.

[0013] Among them, the mass ratio of the rose extract to the selenium source oxidant can be any value among 1:1, 1.25:1, 2:1, 3:1, 4:1, 5:1.

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

[0015] The rose extract can be obtained by the conventional water extraction method, and no specific regulations are made for the steps in this application.

[0016] Further, the selenium source oxidant is selected from one or more of sodium selenite, selenious acid, 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] Among them, the mass ratio of the antioxidant to the selenium source oxidant can be any value among 2:1, 3:1, 4:1, 5:1.

[0020] Preferably, the antioxidant is ascorbic acid.

[0021] Further, the reaction temperature is 10°C - 80°C.

[0022] Among them, the reaction temperature can be selected from any one of 10°C, 40°C, 60°C, 70°C, and 80°C.

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

[0024] Among them, the reaction time can be selected from any one of 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min.

[0025] In a preferred embodiment, a method for preparing nano-selenium using rose flowers, the method comprises the following steps:

[0026] Step 1: Place rose flowers in boiling water at 100°C at a solid-liquid ratio of 1:(20 - 30) g / mL and boil for 10 - 60 min, with a stirring speed of 100 - 600 rpm. Let it stand, filter the supernatant and freeze-dry for 1 - 10 h to obtain rose flower extract;

[0027] Step 2: Stir and react the rose flower extract with a selenium source oxidant and an antioxidant, the reaction temperature is 10°C - 80°C, the reaction time is 10 - 60 min. After the reaction ends, freeze-dry to obtain nano-selenium, and the mass ratio of the rose flower 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, 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, the present application also provides the nano-selenium prepared by the method, the particle size of the nano-selenium is 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 crystal structure of the nano-selenium is spherical, with good stability, and the stability also includes pH stability and ionic stability. The nano-selenium system can maintain stability when placed at room temperature for a long time. And it shows good stability in the pH range of 4 - 10, with no obvious change in particle size and potential, and has a certain pH buffering ability. After adding NaCl and KCl, when the ion concentration is less than 10 mmol / L, the nano-selenium system can still remain clear, with no obvious change in particle size and potential.

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

[0033] It is understandable that auxiliary materials can also be added to the fertilizer product of the present application, and the auxiliary materials can be known auxiliary materials for fertilizer products such as appropriate solvents, solubilizers, cosolvents, emulsifiers, colorants, binders, disintegrants, fillers, lubricants, wetting agents, stabilizers, glidants, preservatives, suspending agents, coating materials, fragrances, antiadhesives, chelating agents, pH regulators, plasticizers, surfactants, release retardants, etc.

[0034] The fertilizer of the present application can be prepared by a general method.

[0035] Preferably, the fertilizer is a tomato fertilizer.

[0036] Preferably, the fertilizer is an antibacterial fertilizer; the antibacterial includes inhibiting Botrytis cinerea, Coniella diplodiella, Fusarium pseudograminearum, Bipolaris sorokiniana, and / or Fusarium graminearum; more preferably, the Botrytis cinerea is Botrytis cinerea; more preferably, the Coniella diplodiella is Coniella diplodiella; more preferably, the Fusarium pseudograminearum is Fusarium pseudograminearum; more preferably, the Bipolaris sorokiniana is Bipolaris sorokiniana; more preferably, the Fusarium graminearum is Fusarium graminearum.

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

[0038] A1) Inhibiting the activity of plant pathogenic bacteria; preferably, the plant pathogenic bacteria include Botrytis cinerea, Coniella diplodiella, Fusarium pseudograminearum, Bipolaris sorokiniana, and / or Fusarium graminearum; more preferably, the Botrytis cinerea is Botrytis cinerea; more preferably, the Coniella diplodiella is Coniella diplodiella; more preferably, the Fusarium pseudograminearum is Fusarium pseudograminearum; more preferably, the Bipolaris sorokiniana is Bipolaris sorokiniana; more preferably, the Fusarium graminearum is Fusarium graminearum;

[0039] A2) Preventing and controlling plant diseases; preferably, the plant diseases include tomato gray mold, grape white rot, wheat basal rot, wheat root rot, and / or wheat head blight;

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

[0041] A4) Increase the selenium content of plants and / or prepare selenium-rich 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 them, enhancing the antioxidant capacity is achieved by increasing the content of peroxidase (POD) in plants and increasing the content of superoxide dismutase (SOD) in plants.

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

[0044] Those skilled in the art can adjust the use concentration of nano-selenium according to the actual situation, and no specific limitation is made in this application.

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

[0046] In this application, rose is first used to prepare nano-selenium, providing a new excellent matrix for the nano-selenium preparation process and a new method for preparing nano-selenium.

[0047] The nano-selenium prepared by the method of this application is more stable, the size and morphology of the prepared nano-selenium are controllable, and at the same time, the biological activity of the material is maintained. Since rose itself has a strong antioxidant capacity, the antioxidant capacity of the modified nano-selenium is also enhanced. Moreover, this nano-selenium also has the functions of inhibiting the activity of plant pathogens, preventing and controlling plant diseases and promoting plant growth, providing a new functional material for the field of plant protection. Description of the Drawings

[0048] The drawings described herein are used to provide a further understanding of the present application, form a part of the present application, and 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:

[0049] Figure 1 It is a statistical chart of the influence of the addition ratio of selenium precursor to antioxidant (reducing agent) on the particle size of nano-selenium;

[0050] Figure 2 It is a statistical chart of the influence of reaction temperature on the particle size of nano-selenium;

[0051] Figure 3 Statistical chart of the effect of the addition amount of freeze-dried rose powder on the particle size of nano-selenium;

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

[0053] Figure 5 Particle size diagram of nano-selenium prepared by the method of Example 2;

[0054] Figure 6 Potential diagram of nano-selenium prepared by the method of Example 2;

[0055] Figure 7 Diagram of the changes in the particle size and potential of nano-selenium at different pH values;

[0056] Figure 8 Diagram of the changes in the particle size and potential of nano-selenium in different concentrations of NaCl;

[0057] Figure 9 Diagram of the changes in the particle size and potential of nano-selenium in different concentrations of KCl;

[0058] Figure 10 Diagram of the changes in the particle size and potential of nano-selenium in different concentrations of CaCl2;

[0059] Figure 11 SEM image of nano-selenium prepared by the method of Comparative Example 1;

[0060] Figure 12 Schematic diagram of the stability experiment of nano-selenium prepared by the methods of Example 2 and Example 3. The nano-selenium prepared by the method of Example 2 is on the left, and the nano-selenium prepared by the method of Example 3 is on the right;

[0061] Figure 13 Schematic diagram of the antibacterial activity of different antibacterial components against Botrytis cinerea of tomatoes;

[0062] Figure 14 Standard curve diagram of nano-selenium against Botrytis cinerea of tomatoes;

[0063] Figure 15 Schematic diagram of the antibacterial activity of different concentrations of nano-selenium against Botrytis cinerea of tomatoes;

[0064] Figure 16 Schematic diagram of the antibacterial activity of nano-selenium against Coniella diplodiella, Rhizoctonia cerealis, Bipolaris sorokiniana and Fusarium graminearum of wheat;

[0065] Figure 17 Statistical chart of the free radical scavenging rate;

[0066] Figure 18 Statistical chart of the POD content in tomatoes;

[0067] Figure 19 It is a statistical chart of the SOD content in tomatoes;

[0068] Figure 20 It is a statistical chart of the chlorophyll content in tomatoes;

[0069] Figure 21 It is a statistical chart of the amino acid content in tomatoes;

[0070] Figure 22 It is a statistical chart of the height of tomatoes;

[0071] Figure 23 It is a statistical chart of the biomass of tomatoes. Detailed implementation manners

[0072] In order to more clearly illustrate the overall concept of this application, the following will be described in detail by way of examples in conjunction with the accompanying drawings of the specification. In the following description, a large number of specific details are given to provide a more thorough understanding of the present invention. However, it is obvious to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0073] Before further describing the specific implementation manners of the present invention, it should be understood that the protection scope of the present invention is not limited to the following specific implementation manners; it should also be understood that the terms used in the embodiments of the present invention are for describing specific implementation manners, rather than for limiting the protection scope of the present invention. The test methods without specific conditions noted in the following examples are generally carried out under conventional conditions, or according to the conditions recommended by each manufacturer.

[0074] It should be noted that the terms used here are only for describing specific implementation manners, and are not intended to limit the exemplary implementation manners according to this application. As used here, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or their combinations.

[0075] When the embodiments give a numerical range, it should be understood that unless otherwise stated in the present invention, any value between the two endpoints of each numerical range and any one of the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art of this technology. In addition to the specific methods, devices, and materials used in the embodiments, according to the knowledge of those skilled in the art of this technology and the description of the present invention, any methods, devices, and materials of the prior art similar to or equivalent to those described in the embodiments of the present invention can also be used to implement the present invention.

[0076] Unless otherwise specified, in the following embodiments, reagents or instruments without indicating the manufacturer can be obtained as conventional products through commercial purchase.

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

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

[0079] In the following examples, unless otherwise specifically stated, % represents wt%, that is, weight percentage.

[0080] Example 1 Optimization of Preparation Conditions of Nano Selenium

[0081] This example provides a method for preparing nano selenium, which is specifically as follows:

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

[0083] Using a 1 L beaker, place 500 mL of water on a magnetic stirrer with a stirring speed of 400 rpm and a temperature of 100 °C. After the temperature rise is completed, place 20 g of dried rose flowers in the water and boil for 30 min, then let it stand for 4 h. After the supernatant is filtered twice with filter paper, it is placed in a freeze dryer and freeze-dried for 8 h to obtain freeze-dried rose powder.

[0084] Step 2: Preparation of nano selenium:

[0085] Place 0.08 g of freeze-dried rose powder in 100 mL of double-distilled water at a temperature of 40 °C, add sodium selenite and ascorbic acid with a mass ratio of 1:3 (40 mg of sodium selenite and 120 mg of ascorbic acid), stir for 30 min, and then freeze-dry to obtain nano selenium particles (SeNPs).

[0086] On this basis, the effects of the addition amount of antioxidant, preparation temperature, and the addition amount of freeze-dried rose powder on the particle size and potential of nano selenium were optimized respectively. The particle size and potential of nano selenium were measured by dynamic light scattering (DLS) and SEM.

[0087] (1) Optimization of the addition amount of antioxidant

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

[0089] The preparation method of nano-selenium includes: putting 0.08 g of freeze-dried rose powder into 100 mL of double-distilled water, adding 0.04 g of sodium selenite and 0.04 g, 0.12 g, 1.2 g of ascorbic acid, stirring for 30 min, and freeze-drying to obtain nano-selenium particles. The remaining steps are the same as those described above, and the results are shown in Table 1. Plotting from Table 1 gives 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, it can be seen that the addition amount of the antioxidant has a certain influence on the particle size of nano-selenium particles. When the addition amount of the antioxidant is 0.12 g, the particle size is the smallest, reaching 167 nm. At this time, the mass ratio of the antioxidant (ascorbic acid) to sodium selenite is 3:1.

[0093] (2) Optimization of the preparation temperature

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

[0095] The preparation method of nano-selenium includes: putting 0.08 g of freeze-dried rose powder into 100 mL of double-distilled water, at temperatures of 10 °C, 40 °C, 60 °C, 70 °C or 80 °C, adding sodium selenite and ascorbic acid with a mass ratio of 1:3, stirring for 30 min, and freeze-drying to obtain nano-selenium particles. The remaining steps are the same as those described above, and the results are shown in Table 2. Plotting from Table 2 gives 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, it can be seen that the reaction temperature has a certain influence on the particle size of nano-selenium particles. When the temperature is 70 °C, the particle size is the smallest, reaching 109 nm.

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

[0100] Under the optimized conditions of step (2), nano-selenium particles are prepared with different addition amounts of freeze-dried rose powder respectively.

[0101] The preparation method of nano-selenium includes: putting 0.02 g, 0.05 g, 0.08 g, 0.1 g, 0.5 g, 1 g of freeze-dried rose powder into 100 mL of double-distilled water, at a temperature of 70 °C, adding sodium selenite and ascorbic acid with a mass ratio of 1:3, stirring for 30 min, and freeze-drying to obtain nano-selenium particles. The remaining steps are the same as those described above, and the results are shown in Table 3. Plotting from Table 3 gives 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] As can be seen from Table 3 and Figure 3 the results, the addition amount of freeze-dried rose powder has a certain influence on the particle size of nano-selenium particles. When the addition amount of freeze-dried rose powder is 0.05 g, the particle size is the smallest, reaching 95 nm.

[0105] Example 2

[0106] A preferred method for modifying nano-selenium with rose extract obtained according to Example 1 includes:

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

[0108] Using a 1 L beaker, place 500 mL of water on a magnetic stirrer with a stirring speed of 400 rpm and a temperature of 100 °C. After the temperature rise is completed, place 20 g of dried rose flowers in the water and boil for 30 min, then let it stand for 4 h. The supernatant is filtered twice with filter paper and then placed in a freeze dryer for 8 h to obtain freeze-dried rose powder.

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

[0110] Place 0.05 g of freeze-dried rose powder in 100 mL of double-distilled water at a temperature of 70 °C, add sodium selenite and ascorbic acid with a mass ratio of 1:3 (40 mg of sodium selenite and 120 mg of ascorbic acid), stir for 30 min, and then freeze-dry to obtain nano-selenium particles (SeNPs).

[0111] Observation of nano-selenium by scanning electron microscope (SEM), the results are as Figure 4 shown. The SEM image shows that the nano-selenium particles obtained in Example 2 are stable spherical structures with a particle size of 104 nm. The particle size, potential, and appearance morphology of nano-selenium are measured by dynamic light scattering (DLS) and SEM. Finally, the prepared nano-selenium has a particle size of about 90 - 100 nm ( Figure 5 ), and a potential of about -50 - -30 mV ( Figure 6 ).

[0112] In this example, the stability test of the nano-selenium particles prepared by the preferred method was carried out, especially regarding the influence of pH value and different ions on the stability of nano-selenium particles.

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

[0114] The specific test method is as follows: Adjust the pH of the selenium nanoparticle suspension, using formic acid and sodium hydroxide to adjust the pH respectively. To reduce experimental differences, within 1 minute of treatment, measure its particle size and zeta potential. The results are shown in Table 4, and graphs are obtained from 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 shown, the pH value significantly affects the stability of selenium nanoparticles by changing their surface electrochemical properties and particle size. When the pH value is 2, the influence on the stability of selenium nanoparticles is the most significant, and the corresponding particle size and zeta potential are 142 nm and -5 mV respectively.

[0118] This is because freeze-dried roses contain various components, including soluble sugars and polyphenolic substances. These components are rich in functional groups such as carboxyl, amino, and hydroxyl groups. These groups dissociate in aqueous solution to generate negative charges. Changes in the pH value will change these surface charges, leading to the formation and breakage of chemical bonds between selenium nanoparticles, thereby affecting their aggregation or disaggregation behavior, and ultimately changing the key stability parameters (such as zeta potential and particle size). It should be noted that in this example, selenium nanoparticles show good stability in the pH range of 4 - 10, with extremely small changes in particle size and zeta potential, indicating strong pH tolerance. This phenomenon suggests that selenium nanoparticles prepared with roses as a stabilizer may have a certain pH buffering ability, which helps to maintain a relatively stable particle size distribution in different pH environments.

[0119] 2. Influence of ion species on the stability of selenium nanoparticles

[0120] Ion type and concentration are key factors determining the stability of selenium nanoparticles in solution. To study these effects, in this example, different concentrations of NaCl, KCl, and CaCl2 were added to the selenium nanoparticle suspension respectively, treated for 1 minute, and the changes in their colloidal properties were evaluated by visual observation, particle size measurement, and zeta potential analysis.

[0121] The results are shown in Table 5, and graphs are obtained from Table 5 Figures 8 - 10 。

[0122] Table 5

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

[0124] As shown in Table 5 and Figures 8 - 10It can be seen that the addition of NaCl and KCl did not cause visible precipitation in the suspension, and it 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 to that at 5 mmol / L.

[0125] It is worth noting that CaCl2 showed the strongest effect on disrupting stability, which could immediately induce visible flocculation and significantly reduce the absolute value of the zeta potential. When the concentration of CaCl2 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 multivalent cations, and their stability followed the order of NaCl < KCl < CaCl2. These findings highlighted 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, nano-selenium particles (SeNPs) prepared using chitosan oligosaccharide were provided.

[0128] Specifically, 400 mg of chitosan oligosaccharide was mixed evenly with 100 mL of ultrapure water, and 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, agglomeration 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 was taken, the temperature was 70 °C, 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 appearance morphology of nano-selenium were measured by dynamic light scattering (DLS) and SEM. The results showed that the potential was 0.21mV and the average particle size was 3920nm.

[0134] In addition, the present embodiment also conducted a stability test on the nano-selenium particles prepared by the methods of Example 3 and Example 2. The test method was to place the nano-selenium particles prepared by the methods of Example 3 and Example 2 at room temperature for 5 minutes and then observe the system conditions. Figure 12 As shown (the left is the nano-selenium prepared by the method of Example 2, and the right is the 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 adding rose freeze-dried powder as a stabilizer will quickly agglomerate and settle. The nano-selenium particle system prepared by the method of Example 2 is more stable, more active, and can be stored for a longer time.

[0135] In summary, roses are rich in amino acids, polyphenols, sugars and other substances, which can be used as natural templates. Therefore, the freeze-dried powder template prepared by roses is rich in hydroxyl, carboxyl, amino, carbonyl and hydrophobic regions, etc., which can be combined with selenium through electrostatic forces, secondary bonds and hydrophobic interactions, effectively preventing selenium particles from combining and agglomerating with each other, and can slow down and control the growth between particles, thereby forming stably 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 no freeze-drying process is performed.

[0138] Step 1: Preparation of rose extract:

[0139] Use a 1L beaker and place 500mL of water in a magnetic stirrer at a stirring speed of 400 and a temperature of 100°C. After heating, place 20g of dried rose flowers in water and boil for 30min, then let stand for 4h. Filter the supernatant twice with filter paper to obtain rose flower extract.

[0140] Step 2: Preparation of Nano-Selenium:

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

[0142] The particle size, potential and appearance of nano-selenium were measured by dynamic light scattering (DLS) and SEM, and the results showed that the potential was -0.34mV and the average particle size was 225nm. It can be seen that the nano-selenium particles prepared by freeze-drying rose extract as a stabilizer have a smaller particle size.

[0143] Example 5 Antibacterial Activity of Nano Selenium against Plant Pathogenic Bacteria

[0144] In this example, the nano selenium prepared by the preferred method of Example 2, Example 3 and Comparative Example 1 was used as a sample. For Botrytis cinerea of tomato, the differences between nano selenium and the common fungicides iprodione and boscalid were compared, and the EC50 of nano selenium against Botrytis cinerea of tomato was determined. Then, the antibacterial activities of nano selenium against Coniella diplodiella, wheat sharp eyespot pathogen, wheat root rot pathogen and Gibberella zeae were measured respectively.

[0145] 1. Antibacterial Rate Experiment of Nano Selenium against Botrytis cinerea of Tomato

[0146] In this example, the laboratory routine treatment method was adopted to conduct the antibacterial rate experiment operation:

[0147] (1) Medicament Treatment

[0148] According to the test treatment, 90 mL of PDA medium was filled into a conical flask, sterilized by high pressure and reserved for use. Before the medicament treatment, the pre - quantified and sterilized PDA medium was melted. Under aseptic conditions, the medicament solution was quantitatively sucked and added into the above - mentioned PDA medium cooled to 50℃ - 60℃, and 2 - 3 drops of lactic acid were added. After mixing evenly, it was equally poured into 4 petri dishes with a diameter of 90 mm to make the corresponding concentration of medicament - containing plates (low concentration was 1 mg / L, high concentration was 10 mg / L), and the treatment without medicament was set as the blank control, and iprodione and boscalid were used as positive controls.

[0149] (2) Inoculation

[0150] Under aseptic conditions, a 5 - mm - diameter sterilized borer was used to cut a mycelial cake from the outer edge of the pathogen colony cultured in the PDA medium. The mycelial cake was inoculated in the center of the medicament - containing plate with an inoculator, with the mycelial surface facing up. The petri dish lid was covered and cultured in an incubator at 27±1℃.

[0151] (3) Investigation

[0152] After culturing in a biological incubator at 27±1℃ for 48 hours (it can be measured when observing that the blank grows about 3 - 4 cm), the colony diameter was measured with a caliper. Each colony was measured once for the diameter vertically by the cross - method, and the average value was taken.

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

[0154] Table 6 Nano Selenium against Botrytis cinerea of Tomato, with High and Low Concentrations Respectively

[0155] Sample Bacteriostatic 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 Boscalid 10 mg / L 87 Boscalid 1 mg / L 74

[0156] From Table 6 and Figure 13The results show that the bacteriostatic rate of SeNPs prepared by the method of Example 2 against Botrytis cinerea of tomatoes can reach 93%, that is, the SeNPs prepared by the method of Example 2 have a high inhibitory effect on Botrytis cinerea of tomatoes and can effectively prevent and control the occurrence of Botrytis cinerea of tomatoes.

[0157] 2. Calculation of EC50 of SeNPs prepared by the method of Example 2 against Botrytis cinerea of tomatoes

[0158] The specific method is as follows: taking the logarithm of the agent concentration (mg / L) as the independent variable X and the probit value of the mycelial growth inhibition rate as the dependent variable Y, establishing a virulence regression equation respectively to calculate EC50.

[0159] The standard curve is as Figure 14 shown, and the results are as Figure 15 shown. It is calculated that the EC50 of nano-selenium against Botrytis cinerea of tomatoes = 4.86 mg / L.

[0160] 3. Bacteriostatic activities of SeNPs prepared by the method of Example 2 against Coniella diplodiella, Rhizoctonia solani Kühn of wheat, Bipolaris sorokiniana of wheat and Gibberella zeae of wheat, etc.

[0161] The specific method is as follows: the steps of the bacteriostatic test are the same as those described in the experiment of the bacteriostatic rate of nano-selenium against Botrytis cinerea of tomatoes.

[0162] The results are as Figure 16 shown. Thus, it can be seen that the nano-selenium prepared by the method of Example 2 has inhibitory effects on Coniella diplodiella, Rhizoctonia solani Kühn of wheat, Bipolaris sorokiniana of wheat and Gibberella zeae of wheat.

[0163] Influence of nano-selenium of Example 6 on the growth of tomatoes

[0164] In this example, 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 explore the influence of nano-selenium on the growth of tomatoes.

[0165] The specific method is as follows: placing tomato seedlings under suitable conditions of temperature, humidity and sunshine (16 h during the day, 25 °C, 70% humidity, 8 h at night, 20 °C, 50% humidity), culturing for a period of time to stabilize the growth status. Wrapping the soil with tin foil to avoid excessive dripping of the liquid medicine into the soil. Diluting the original solution of SeNPs preparation 10 times (70 mg / L) and 100 times (7 mg / L) with pure water as the high-concentration (H) treatment group and the low-concentration (L) treatment group respectively, filling them into a sprayer and evenly spraying them on the leaves of tomato seedlings until the liquid medicine is evenly sprayed. Spray again after 7 days after spraying. About 2 h after the liquid medicine dries, sample and measure.

[0166] Using the nano-selenium synthesized by chitosan oligosaccharide as SeNPs1 and the nano-selenium synthesized by the rose freeze-dried powder of Example 2 as SeNPs2, making a graph, and the results are asFigures 17 - 23 as shown

[0167] From Figure 17 As can be seen from the results, the nano-selenium synthesized from the freeze-dried rose powder of Example 2 at a low concentration (L) can improve the antioxidant (free radical scavenging) ability of tomatoes.

[0168] From Figure 18 As can be seen from the results, the application of nano-selenium can increase the content of peroxidase (POD) in tomatoes. Moreover, the nano-selenium synthesized from the freeze-dried rose powder of Example 2 at a high concentration (H) has a more excellent promoting effect compared with the nano-selenium synthesized using chitosan oligosaccharide.

[0169] From Figure 19 As can be seen from the results, the application of nano-selenium at a low concentration can increase the content of superoxide dismutase (SOD) in tomatoes. Among them, the nano-selenium synthesized from the freeze-dried rose powder of Example 2 is better than the nano-selenium synthesized using chitosan oligosaccharide. However, the nano-selenium synthesized using chitosan oligosaccharide shows an inhibitory effect at a high concentration.

[0170] From Figure 20 As can be seen from the results, the application of the nano-selenium synthesized from the freeze-dried rose powder of Example 2 can increase the chlorophyll content of tomatoes.

[0171] From Figure 21 As can be seen from the results, the application of nano-selenium at a low concentration can increase the amino acid content of tomatoes, and the nano-selenium synthesized from the freeze-dried rose powder of Example 2 has a more excellent promoting effect compared with the nano-selenium synthesized using chitosan oligosaccharide. However, the nano-selenium at a high concentration shows an inhibitory effect.

[0172] From Figure 22 As can be seen from the results, the application of nano-selenium can increase the plant height of tomatoes, and the nano-selenium synthesized from the freeze-dried rose powder of Example 2 has a more excellent promoting effect compared with the nano-selenium synthesized using chitosan oligosaccharide.

[0173] From Figure 23 As can be seen from the results, the application of nano-selenium can increase the biomass of tomatoes, and the nano-selenium synthesized from the freeze-dried rose powder of Example 2 has a more excellent promoting effect compared with the nano-selenium synthesized using chitosan oligosaccharide.

[0174] In summary, the nano-selenium (SeNPs2) prepared from the freeze-dried rose powder has a more significant effect on improving the growth of tomatoes than the nano-selenium (SeNPs1) prepared from chitosan oligosaccharide. However, the effect of nano-selenium has a significant concentration effect. SeNPs2 can improve the antioxidant ability and chlorophyll content of tomatoes, but high-concentration SeNPs2 may have negative effects, so attention should be paid to the dosage. Nano-selenium at an appropriate concentration can promote the growth of tomatoes.

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

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

[0177] Moreover, selenium was applied during the growth period of tomato seedlings. The specific fertilization method was as follows: The tomato seedlings were placed under suitable conditions of temperature, humidity, and sunlight (16 h during the day, 25 °C, 70% humidity, 8 h at night, 20 °C, 50% humidity) for a period of time to stabilize the growth status. The soil was wrapped with tinfoil to prevent excessive dripping of the liquid medicine into the soil. The stock solution for preparing SeNPs was diluted 10 times (70 mg / L) with pure water and then filled into a sprayer and evenly sprayed onto the leaves of the tomato seedlings until the liquid medicine was evenly distributed. Spraying was carried out once every 7 days after the first spraying, and a total of 2 sprayings were carried out. The experimental group without spraying the sample was used as a blank control. After the results were obtained, samples were taken to measure the selenium content in the fruits.

[0178] During the fruiting period, the (average) selenium content in the fruits was measured to be 0.46 mg / kg, meeting the requirements for selenium-rich products (0.02 - 1.0 mg / kg), while the selenium content in the fruits of the blank control was 0.0647 mg / kg. That is, it can be considered that nano-selenium can effectively enrich selenium in tomatoes.

[0179] The above description is only for the embodiments of the present application and is not intended to limit the present application. For those skilled in the art, various modifications and changes can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. Application of rose in preparation of nano-selenium.

2. A method for preparing nano-selenium using roses, characterized in that, The method comprises the following steps: Step 1, preparing rose extract; Step 2, reacting the rose extract with a selenium source oxidant and an antioxidant.

3. The method according to claim 2, characterized in that, The preparation method of the rose extract comprises: obtaining rose extract by water extraction method; preferably, the method further comprises the step of freeze-drying the rose extract; preferably, in Step 2, the mass ratio of the rose extract to the selenium source oxidant is (1 - 5):1; more preferably, in Step 2, the mass ratio of the rose extract to the selenium source oxidant is 1.25:

1.

4. The method according to claim 2, wherein The selenium source oxidant is selected from one or more of sodium selenite, selenious acid, and selenium dioxide.

5. The method according to claim 2, characterized in that, 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.

6. The method according to claim 2, characterized in that The reaction temperature is 10°C - 80°C.

7. The method according to claim 2, characterized in that, The reaction time is 10 - 60 min.

8. The nano-selenium prepared by the method according to any one of claims 2-7, characterized in that, The particle size of the nano-selenium is 90 - 360 nm; preferably, 90 - 110 nm.

9. A fertilizer containing the nano-selenium as claimed in claim 8.

10. Application of the nano-selenium as claimed in claim 9 in any one or more of A1) - A4): A1) Inhibiting the activity of plant pathogens; preferably, the plant pathogens include Botrytis cinerea, Coniella diplodiella, Fusarium pseudograminearum, Bipolaris sorokiniana, and / or Fusarium graminearum; more preferably, the Botrytis cinerea is Botrytis cinerea; more preferably, the Coniella diplodiella is Coniella diplodiella; more preferably, the Fusarium pseudograminearum is Fusarium pseudograminearum; more preferably, the Bipolaris sorokiniana is Bipolaris sorokiniana; more preferably, the Fusarium graminearum is Fusarium graminearum; A2) Controlling plant diseases; preferably, the plant diseases include Botrytis cinerea, Coniella diplodiella, Fusarium pseudograminearum, Bipolaris sorokiniana, and / or Fusarium graminearum; A3) Promoting plant growth; preferably, promoting tomato growth includes enhancing the antioxidant capacity of the plant, increasing the peroxidase content of the plant, increasing the superoxide dismutase content of the plant, increasing the chlorophyll content of the plant, increasing the amino acid content of the plant, increasing the plant height and / or increasing the biomass of the plant; preferably, the plant is tomato; A4) Increasing the selenium content of the plant and / or preparing selenium-rich products; preferably, the plant is tomato.

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