Heavy metal detoxification organic leaf surface control and repair agent and preparation method and application thereof

Abstract

The application discloses a heavy metal detoxification organic leaf surface resistance control restorer and a preparation method and application thereof. The leaf surface resistance control restorer comprises the following raw materials in parts by weight: SAC 15-30 parts; DMSA 15-30 parts; glycine 15-30 parts; a surfactant 1-5 parts; and an ultraviolet light stabilizer 1-5 parts. A DMSA solution, an SAC solution and a glycine solution are respectively prepared, and the three solutions are fully mixed; the pH value is adjusted to 5-7; the surfactant and the ultraviolet light stabilizer are added and uniformly stirred to obtain the leaf surface resistance control restorer. The leaf surface resistance control restorer is prepared from SAC, DMSA and glycine, can be applied to different types and properties of soil, has a wide application range, can directly participate in the metabolism of plants, reduce the toxicity of heavy metals and the transportation of heavy metals from stems to leaves, has low toxicity and good water solubility, and can effectively solve the problems of single detoxification and short window period of existing leaf surface resistance control agents.

Description

Technical Field

[0001] This invention relates to the field of soil heavy metal pollution prevention and control technology, specifically to a heavy metal detoxification organic foliar inhibitor and its preparation method and application. Background Technology

[0002] Using foliar physiological barrier agents to control the accumulation of heavy metals in crops is a new direction in the research on the prevention and control of heavy metal pollution in farmland in recent years. It mainly reduces or even completely blocks the absorption and transport of heavy metals from roots to grains by means of precipitation or chelation of heavy metals on the cell walls of crops and improving the stress resistance of crops to heavy metals, thereby reducing or blocking the transfer of heavy metals to the food chain.

[0003] Existing foliar inhibitors are generally made from inorganic materials, but the use of inorganic materials has certain drawbacks:

[0004] (1) Firstly, inorganic raw materials lack biodegradability, and long-term use causes environmental pollution and affects the balance of soil ecosystems.

[0005] (2) Secondly, the raw materials are relatively simple and cannot meet the diverse needs of different soil types and crop varieties;

[0006] (3) Thirdly, after micronutrient fertilizers are applied by foliar spraying, the presence of a waxy layer often affects the absorption and utilization of nutrients by the leaves.

[0007] Regarding the leaf surface inhibitors made from the above inorganic raw materials, existing technologies also disclose leaf surface inhibitors using organic raw materials, such as:

[0008] Chinese patent document CN116444310A discloses an organoselenium heavy metal foliar inhibitor and its application. The organoselenium heavy metal foliar inhibitor contains: a selenocyanide-based organoselenium and a thiocyanate; the selenocyanide-based organoselenium is one or more of selenocyano-based organic acid salts, selenocyano esters, and polyselenocyano-based organoselenium compounds. In this scheme, the foliar inhibitor based on selenocyanide-based organoselenium has lower toxicity than inorganic selenium, higher plant tolerance, and allows plants to absorb and utilize higher levels of selenium, resulting in better heavy metal antagonism.

[0009] Chinese patent document CN115093275A discloses a nano-silicon-zinc foliar fertilizer, which is composed of 15-25 parts by weight of a compound amino acid liquid, 10-15 parts by weight of a soluble zinc compound, 10-15 parts by weight of neutral nano-silicon, 0.01-0.02 parts by weight of a foliar fertilizer adjuvant, and the balance being water. The appropriate application time for this novel compound nano-silicon-zinc foliar fertilizer is the early tillering stage, the early booting stage, and the early grain-filling stage. When using it, it should be diluted with water at a ratio of 1:50 and sprayed evenly on both sides of the rice leaves to achieve the effects of reducing cadmium, increasing zinc, and increasing yield.

[0010] The existing organic foliar inhibitors disclosed above mainly use organic selenium and silicon zinc, which still cannot solve the problems of single detoxification, narrow scope of application, short window period and inconvenient application, as well as low efficiency of micronutrient absorption and utilization. Summary of the Invention

[0011] The technical problem this invention aims to solve is to provide an organic foliar inhibitor for heavy metal detoxification and its preparation method. Addressing the problems of existing technologies, this invention uses SAC and DMSA organic compounds as raw materials, combined with glycine ion solution, to formulate an organic foliar inhibitor for heavy metal detoxification. This inhibitor is applicable to different types and properties of soil, has a wide range of applications, and reduces heavy metal toxicity by directly participating in plant metabolism. It exhibits low toxicity and good water solubility, effectively improving upon the limitations of existing foliar inhibitors in terms of their single detoxification method and short detoxification window.

[0012] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0013] In a first aspect, the present invention provides a heavy metal detoxification organic foliar barrier repair agent, comprising the following raw materials in parts by weight:

[0014] SAC 15-30 portions;

[0015] DMSA 15-30 portions;

[0016] 15-30 parts glycine;

[0017] 1 to 5 parts of surfactant;

[0018] 1 to 5 parts of UV stabilizer.

[0019] Furthermore, the surfactant is at least one selected from sodium fatty alcohol polyoxyethylene ether sulfate and sodium alkylbenzene sulfonate. Sodium alkylbenzene sulfonate is preferred. These surfactants can reduce the surface tension of water, improve the wettability and adhesion of pesticides on leaf surfaces, and promote the penetration and absorption of pesticides on leaf surfaces. Simultaneously, these surfactants can also improve the stability of pesticides and extend their service life.

[0020] Furthermore, the ultraviolet light stabilizer includes plant flavonoids and polyphenolic quinone compounds. Even further, the polyphenolic quinone compounds include tea polyphenols, bamboo leaf polyphenols, red wine polyphenols, etc. Preferably, the ultraviolet light stabilizer is a plant flavonoid.

[0021] Secondly, the present invention provides a method for preparing the above-mentioned heavy metal detoxification organic foliar barrier repair agent, comprising the following steps:

[0022] S1. Prepare DMSA solution, SAC solution and glycine solution respectively, and then mix the three solutions thoroughly.

[0023] S2. Next, adjust the pH of the mixed solution obtained in step S1 to 5-7.

[0024] S3. Then add the surfactant, and finally add the UV stabilizer. Stir well to obtain the final product.

[0025] Furthermore, the DMSA solution described in step S1 is prepared by the following method:

[0026] DMSA is added to the first solvent at a solid-liquid ratio of 1g:4-6mL and mixed, then ultrasonically dispersed for 30-40 minutes to obtain a DMSA solution. The preferred concentration of the DMSA solution is 1g:5mL.

[0027] Preferably, the first solvent is dimethyl sulfoxide, methanol, ethanol, or water. More preferably, it is dimethyl sulfoxide.

[0028] Furthermore, the SAC solution described in step S1 is prepared by the following method:

[0029] Add SAC to water at a solid-liquid ratio of 1g:9-11mL, mix, heat to 60-70℃, stir until dissolved, and cool to obtain the final product. The preferred concentration of the SAC solution is 1g:10mL.

[0030] Further, the glycine solution in step S1 is prepared by the following method:

[0031] Glycine is added to water at a solid-liquid ratio of 1g:9-11mL, mixed, heated to 60-70℃, stirred until dissolved, and then cooled to obtain the final product. The preferred concentration of the glycine solution is 1g:10mL.

[0032] Furthermore, the method also includes step S4, removing impurities and particles from the mixture obtained in step S3 to ensure the purity and transparency of the leaf surface inhibitor. This can be achieved by removing impurities and particles from the mixture using a filter screen or membrane filter.

[0033] Furthermore, in step S2, the pH is adjusted to 5–7 using acetic acid. Under pH conditions of 5–7, the three organic compounds DMSA, SAC, and glycine do not react, which helps to improve the performance and stability of the foliar inhibitor.

[0034] Thirdly, the present invention provides an application of the above-mentioned heavy metal detoxification organic foliar barrier repair agent. When the heavy metal detoxification organic foliar barrier repair agent is sprayed on the leaves of rice from the seedling stage to the heading stage, it can accumulate heavy metals absorbed by the roots of rice into the stem base and reduce the translocation of heavy metals from the stem base to the stem and leaves.

[0035] The components and their main functions in this invention are as follows:

[0036] (1) S-Allyl-L-Cysteine: also known as allicin; English name: S-ALLYL-L-CYSTEINE; abbreviated as SAC. It is a naturally occurring amino acid with excellent biological activity. In the existing technology, based on the fact that SAC can chelate with a variety of heavy metals in animal cells to form highly stable chelates, reducing the mobility of heavy metals, and can also eliminate a large number of oxygen free radicals generated in cells due to heavy metal stress, reducing the number of apoptotic cells, SAC is widely used in the medical field to treat heavy metal poisoning.

[0037] In this invention, SAC can bind with heavy metal ions on the surface of plant roots to form stable complexes and induce plants to produce resistance genes and related enzymes, thereby improving the plant's resistance and tolerance to heavy metals and reducing the damage of heavy metals to plants.

[0038] (2) DMSA, dimercaptosuccinate, is a heavy metal chelating agent containing a dithiol group. In the prior art, based on the fact that SAC can form chelates with heavy metals in humans and animals, and then be excreted through the excretory system to achieve detoxification, SAC is also widely used in the medical field to treat heavy metal poisoning.

[0039] In this invention, DMSA can bind with heavy metal ions in plants to form stable water-soluble chelates. At the same time, because it contains dithiol groups, it can bind with thiol groups in plant cells damaged by heavy metal ions, restore the activity of enzymes containing thiol groups, reduce the toxic effects of heavy metal ions, thereby protecting plants from damage by heavy metal ions and reducing toxicity.

[0040] (3) Glycine: also known as aminoacetic acid, is a constituent amino acid of the endogenous antioxidant reduced glutathione. It has a simple molecular structure and good water solubility and biological activity.

[0041] In this invention, glycine enters the plant and can act as an antioxidant in the organism, protecting cells from oxidative stress damage; it can also reduce the damage of heavy metal ions to animal cells by binding with heavy metal ions in the plant, regulating metal ion metabolism, and promoting cell repair.

[0042] (4) The surfactant added to the leaf surface barrier repair agent of the present invention can induce physiological reactions and stomatal changes in crops, resulting in increased crop transpiration, reduced leaf surface temperature, and enabling leaves to perform photosynthesis under strong light without being damaged.

[0043] (5) The leaf surface barrier repair agent of the present invention also contains an ultraviolet light stabilizer, which can protect crops and vegetables from ultraviolet damage, and make the pesticide sprayed on crops and vegetables effectively adhere to the surface of plant leaves or pests, greatly improving the stability and adhesion of pesticides, thereby improving the longevity of pesticide efficacy.

[0044] The beneficial effects of this invention are:

[0045] Compared with existing technologies, the advantages of the heavy metal detoxification organic foliar barrier repair agent provided by this invention are mainly as follows:

[0046] Firstly, it has a wide range of applications, suitable for different types and properties of soil. Secondly, it can protect plants from oxidative damage by participating in plant metabolic processes and reduce heavy metal toxicity through plant tolerance mechanisms. Thirdly, it broadens the application window for crops and is easy to apply. Fourthly, it reduces leaf surface tension, improves leaf absorption efficiency, and alleviates micronutrient deficiencies. Specifically:

[0047] (1) The foliar inhibitor provided by this invention is an organic product, formulated with SAC and DMSA organic compounds as raw materials and combined with glycine ion solution. The main principle is that the amino acids (SAC, glycine) and DMSA (dimercaptosuccinic acid) in the components can undergo complexation reactions with the heavy metal Cd in the crop leaves after entering the crop leaves. At the same time, amino acids can also promote the synthesis of proteins in the crop, passivating and precipitating them, thereby reducing the toxicity of heavy metals by directly participating in the plant's metabolic processes. Moreover, amino acids, as antioxidants in organisms, can protect cells from oxidative stress damage.

[0048] (2) The organic raw materials SAC, DMSA, and glycine in the foliar inhibitor provided by this invention are all small-molecule organic compounds (generally referring to organic compounds with a molecular weight of no more than 10,000). Small-molecule organic compounds have good penetration, wetting, and surface tension reduction functions. After being sprayed with the solution, they can adhere to plant leaves and form a thin film, which can increase the absorption area of ​​nutrients by the leaves. In addition, these small-molecule organic compounds have a good chelation or complexation effect on trace elements, which can improve the absorption and utilization efficiency of trace elements. Conventional foliar inhibitors require the application of additional corresponding elements to supplement the trace element requirements.

[0049] Therefore, the foliar inhibitor provided by this invention can reduce leaf surface tension, improve the absorption efficiency of micronutrients by leaves, and alleviate micronutrient deficiency in plants. It effectively solves the problem in existing technologies where the presence of a hydrophobic waxy layer on the surface of plant leaves makes it difficult for liquids to wet the leaves; and the waxy layer hinders the absorption and utilization of nutrients by leaves after foliar spraying of micronutrient fertilizers.

[0050] (3) The leaf surface control and repair agent provided by the present invention has good comprehensive performance, can target multiple heavy metal elements at the same time, solves the problem of single detoxification of existing leaf control agent products, avoids the use of multiple different inorganic leaf surface control agents, reduces the complexity and cost of use; and can be applied to different types and properties of soil, with a wide range of applications.

[0051] (4) Taking rice as an example, most existing foliar inhibitor products are used from the tillering stage to the heading stage, but actual application is often difficult due to weather conditions. The organic foliar inhibitor product provided by this invention can improve the application window to the seedling stage to the heading stage of rice, which can broaden the window and solve the problems of short window and difficult application of existing foliar inhibitor products.

[0052] In summary, the foliar inhibitor provided by this invention has a wide range of applications; it has diverse detoxification methods, low toxicity, good water solubility, a long application window, and is easy to apply. At the same time, it can also improve the absorption and utilization efficiency of micronutrients by crops and promote crop growth. Detailed Implementation

[0053] As used in this article:

[0054] "Prepared from" is synonymous with "comprising". The terms "comprising", "including", "having", "containing", or any other variations thereof as used herein are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not necessarily limited to those elements, but may include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0055] The conjunction "composed of..." excludes any unspecified elements, steps, or components. If used in a claim, this phrase makes the claim closed, excluding materials other than those described, except for associated conventional impurities. When the phrase "composed of..." appears in a clause of the body of a claim rather than immediately following it, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0056] When a quantity, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper and lower preferred values, this should be understood as specifically disclosing all ranges formed by any pair of any upper or preferred value with any lower or preferred value, regardless of whether the range is disclosed individually. For example, when the range “1–5” is disclosed, the described range should be interpreted as including ranges “1–4”, “1–3”, “1–2”, “1–2 and 4–5”, “1–3 and 5”, etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include its endpoints and all integers and fractions within that range.

[0057] In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0058] "Parts by weight" or "parts of mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. One part can represent any unit mass, such as 1g or 2g. If we say that component A has "a" parts of mass and component B has "b" parts of mass, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it can mean that the mass of component A is aK and the mass of component B is bK (where K is any number representing a multiplier). It is important to understand that, unlike parts by mass, the sum of the mass parts of all components is not limited to 100 parts.

[0059] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0060] This invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this invention.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0062] The raw materials used in the following examples and their sources are as follows:

[0063] DMSA was purchased from Nanjing Dongna Biotechnology Co., Ltd.; S-allyl-L-cysteine ​​(SAC) was purchased from Sinopharm Group; glycine (aminoacetic acid) was purchased from Shanghai Tufeng Biotechnology Co., Ltd.; the surfactant used in the following examples was sodium alkylbenzene sulfonate; the ultraviolet light stabilizer used was plant flavonoids, purchased from Guizhou Daoyuan Biotechnology Co., Ltd.

[0064] I. Preparation of Organic Leaf Surface Inhibitors

[0065] This invention provides a heavy metal detoxifying organic foliar barrier repair agent and its preparation method, comprising the following steps:

[0066] S1. Prepare DMSA solution, SAC solution, and glycine solution separately, as follows:

[0067] (1) Add DMSA to dimethyl sulfoxide according to the solid-liquid ratio of 1g:5mL, mix, and ultrasonically disperse for 30-40min to obtain DMSA solution.

[0068] (2) Add SAC to water and mix according to the solid-liquid ratio of 1g:10mL, heat to 60-70℃, stir until dissolved, and cool to obtain SAC solution.

[0069] (3) Add glycine to water and mix according to the solid-liquid ratio of 1g:10mL. Heat to 60-70℃, stir until dissolved, and cool to obtain glycine solution.

[0070] Next, the three solutions are added to a mixing container and thoroughly mixed using a stirrer to ensure that the components are evenly distributed.

[0071] S2. Next, acetic acid is added to the mixed solution obtained in step S1 to adjust the pH to 5-7. Under the condition of pH 5-7, the three organic compounds DMSA, SAC and glycine do not react, which helps to improve the performance and stability of the foliar inhibitor.

[0072] S3. Then add the surfactant sodium alkylbenzene sulfonate, and finally add the UV stabilizer plant flavonoids. Stir well to obtain the mixture.

[0073] S4. Remove impurities and particles from the mixture obtained in step S3 using a filter screen or membrane filter to ensure the purity and transparency of the leaf surface inhibitor.

[0074] The weight parts of DMSA, SAC, glycine, surfactant, and UV stabilizer in each embodiment and comparative example are shown in Table 1 below:

[0075] Table 1. Weight ratio of each component in each embodiment and comparative example.

[0076]

[0077]

[0078] II. Comparative Experiment on the Effect of Foliar Spraying on Heavy Metal Content in Rice Seedling Stems, Leaves, and Roots

[0079] The tillering stage is the main period of vegetative growth, during which rice plants begin to tiller, that is, new branches grow from the main stem. These branches will gradually develop into new panicles. Therefore, existing foliar inhibitors are usually applied to the leaves of the plant during the tillering stage to improve application efficiency. However, the leaf inhibitor repair agent of this invention contains small molecule organic compounds such as SAC, DMSA, and glycine, which can directly enter the plant and participate in the plant's metabolism. The following experiments verify the effects of the foliar inhibitor repair agent provided by this invention on crops when sprayed during the seedling stage.

[0080] Forty hydroponic containers made of polyethylene (PE) were used, with an upper diameter of 40cm, a lower diameter of 30cm, and a height of 25cm. Each container can hold 10L of basic nutrient solution and 10ml of trace element reserve solution. Rice seedlings were fixed in foam plastic seedling trays and transplanting baskets.

[0081] The hydroponic nutrient solution was prepared using Kimura B nutrient solution and Arnon (1938) AZ trace element nutrient solution, as shown in Table 2. The exogenous Cd concentration was controlled at 10 mg·kg⁻¹. -1 The concentration of exogenous As was controlled at 10 mg·kg⁻¹. -1 .

[0082] The required exogenous As was prepared using a diluted concentrate (Na3AsO4·12H2O, analytical grade, 1000 mg·L⁻¹). -1 Add using the method described above, and with 0.5 mol·L⁻¹ -1 H2SO4 and 2 mol·L -1 NaOH was used to adjust the pH of the nutrient solution to 6.8 (the allowable pH range for this nutrient solution is 6.4–7.2).

[0083] Table 2. Rice hydroponic nutrient solution formula

[0084] <![CDATA[(NH4)2SO4]]> <![CDATA[48.2mg·L -1 ]]> <![CDATA[H3BO3]]> <![CDATA[2.86mg·L -1 ]]> <![CDATA[KH2PO4]]> <![CDATA[24.8mg·L -1 ]]> <![CDATA[CuSO4·5H2O]]> <![CDATA[0.08mg·L -1 ]]> <![CDATA[KNO3]]> <![CDATA[18.5mg·L -1 ]]> <![CDATA[ZnSO4·7H2O]]> <![CDATA[0.22mg·L -1 ]]> <![CDATA[K2SO4]]> <![CDATA[15.9mg·L -1 ]]> <![CDATA[MnCl2·4H2O]]> <![CDATA[1.81mg·L -1 ]]> <![CDATA[Ca(NO3)2]]> <![CDATA[59.9mg·L -1 ]]> <![CDATA[H2MoO·4H2O]]> <![CDATA[0.09mg·L -1 ]]> <![CDATA[MgSO4]]> 65.9 mg·L⁻¹ Ferric citrate 4mg·L-1

[0085] * indicates that 1 ml of Arnon (1938) AZ trace element is added to every 1 L of Kimura B nutrient solution.

[0086] The hydroponic rice variety described in this invention is the conventional rice variety "Xiangwanxian 13". This variety is a conventional mid-maturing late-maturing indica rice. When planted as a double-cropping rice in the middle and lower reaches of the Yangtze River, the average growth period is 115 days, the plant height is 98.5 cm, and the plant type is moderate.

[0087] After breeding the experimental rice samples, seedlings with balanced growth and 5 leaves and 1 heart were selected. After being cleaned with desoiled water and removed from mud, they were transplanted into nutrient solution cultivation devices, 5 holes / pot, 3 seedlings per hole. During the experiment, water was added daily according to the amount of evaporation to maintain a constant water volume, and 400 g·L⁻¹ water was added every 2 days. -1 Adjust the pH of the culture medium with NaOH solution to maintain the pH value within the range of 5.0 to 5.5, and change the nutrient medium every 4 days.

[0088] Table 3. Hydroponic Experiment Treatment Names and Operating Procedures

[0089]

[0090] The results of the study are analyzed as follows:

[0091] Table 4. Effects of foliar spraying of cadmium control agents on cadmium absorption and accumulation in various organs of rice seedlings (μg·kg⁻¹) -1 )

[0092] CK 51.42±2.71a 1299.24±1.57a 270.37±1.15a OY-1 33.46±4.16d 1157.83±1.35ab 479.76±4.58e Y-1 38.34±2.46bc 1321.62±2.55ab 424.6±0.9d Y-2 40.17±2.04bc 1275.38±4.79ab 436.3±0.79d Y-3 43.23±4.9b 1250.27±5.65a 456.41±2.45d Y-4 45.84±0.95b 1358.96±1.08ab 314.42±0.42b Y-5 48.11±1.82ab 1255.41±2.94a 349.37±1.7bc Y-6 44.97±0.51b 1356.46±1.42ab 307.06±1.25b Y-7 40.92±0.21bc 1198.76±2.54ab 380.91±0.95c

[0093] Table 4 shows that there was no significant correlation between the cadmium content in the roots of rice seedlings and the spraying treatments. The cadmium content in the roots of rice seedlings in the CK treatment group was 1299.24 μg·kg⁻¹. -1 The cadmium content in the roots of rice seedlings treated with OY-1 was 1157.83 μg·kg⁻¹. -1 This indicates that the application of foliar inhibitors to each treatment had no significant effect on the cadmium content in the roots of rice seedlings.

[0094] High concentrations of cadmium were accumulated in the stem base of rice seedlings, with the cadmium content in the stem base of seedlings treated with CK reaching 270.37 μg·kg⁻¹. -1 The cadmium content at the stem base of rice seedlings treated with OY-1 was 479.96 μg·kg⁻¹. -1 Compared with the control (CK) treatment, the increase was 77.45%. Treatments Y-1, Y-2, and Y-3 showed increases of 57.04%, 61.37%, and 68.81% respectively compared to the CK treatment, with no significant correlation among the three treatments. Treatments Y-4, Y-5, and Y-6 showed increases of 16.29%, 29.22%, and 13.57% respectively compared to the CK treatment, with no significant correlation among the three treatments. The results indicate that the addition of these three substances significantly increased the accumulation capacity of cadmium in the rice stem base, and the transfer efficiency of cadmium from the rice seedling roots to the stem base significantly increased.

[0095] The cadmium content in the stems and leaves of rice seedlings showed a decreasing trend, with the cadmium content at the stem base of seedlings treated with CK reaching 51.4 μg·kg⁻¹. -1 The cadmium content at the stem base of rice seedlings treated with OY-1 was 33.46 μg·kg⁻¹. -1Compared with the CK treatment, the reduction was 34.92%. Treatments Y-1, Y-2, and Y-3 (3 treatments) showed reductions of 25.44%, 21.88%, and 15.93% respectively compared to the CK treatment, with no significant correlation among the three treatments. Treatments Y-4, Y-5, and Y-6 (3 treatments) showed reductions of 10.85%, 6.44%, and 12.54% respectively compared to the CK treatment. All treatments showed significant differences from the CK.

[0096] In the Y-7 and CK treatments, the cadmium content at the base of rice stems increased, while the cadmium content in the stems and leaves of rice seedlings decreased. Compared with the OY-1 treatment, the cadmium concentration at the base of stems was lower, while the cadmium concentration in the stems and leaves was higher. This indicates that the surfactant added to the foliar inhibitor, when sprayed with the solution, can increase the leaf surface area for nutrient absorption, induce physiological responses in crops, increase the penetration rate of the foliar inhibitor, and reduce the surface tension of the solution.

[0097] The above data indicate that spraying foliar inhibitors can alter the transfer efficiency of cadmium from roots to stem base and from stem base to stem and leaves, causing a large amount of cadmium in rice to accumulate in the stem base and reducing the translocation of cadmium from stem base to stem and leaves.

[0098] Table 5. Effects of foliar spraying of arsenic inhibitors on arsenic absorption and accumulation in various organs of rice seedlings (μg·kg⁻¹) -1 )

[0099] CK 0.40±0.12a 8.52±0.33a 0.54±0.08a OY-1 0.27±0.13d 5.79±0.37e 1.06±0.03e Y-1 0.29±0.12c 6.72±0.27d 0.92±0.02d Y-2 0.29±0.16c 7.60±0.29c 0.74±0.08c Y-3 0.28±0.15c 7.55±0.27c 0.70±0.08c Y-4 0.37±0.16ab 8.08±0.28b 0.60±0.09b Y-5 0.36±0.23ab 7.92±0.36bc 0.59±0.05b Y-6 0.34±0.15b 7.65±0.38bc 0.62±0.13b Y-7 0.35±0.11b 6.57±0.17d 0.85±0.05b

[0100] The total arsenic content in the roots of rice seedlings was significantly higher than that in other vegetative organs. After foliar application of arsenic inhibitors, the total arsenic content in the roots of rice seedlings showed a decreasing trend across all treatments. The arsenic content in the roots of seedlings in the control (CK) treatment reached 8.52 μg·kg⁻¹. -1 The arsenic content in the roots of rice seedlings treated with OY-1 was 5.79 μg·kg⁻¹. -1 Compared with the CK treatment, the reduction was 32.03%. The three treatments, Y-1, Y-2, and Y-3, reduced the levels by 21.12%, 10.86%, and 11.43% respectively compared to the CK treatment, showing significant differences among the treatments. The three treatments, Y-4, Y-5, and Y-6, reduced the levels by 5.26%, 7.13%, and 10.23% respectively compared to the CK treatment. All treatments showed significant differences from OY-1.

[0101] After foliar spraying of the inhibitor on rice seedlings, the total arsenic content in the OY-1 treatment was 1.06 μg·kg⁻¹ compared to the control (CK). -1The increase was 95.93%, showing a significant difference. Treatments Y-1, Y-2, and Y-3, compared to the CK treatment, increased by 70.56%, 37.59%, and 30.74%, respectively, and each treatment showed a significant difference from OY-1. Treatments Y-4, Y-5, and Y-6, compared to the CK treatment, increased by 10.19%, 10.19%, and 14.63%, respectively. Each treatment showed a significant difference from OY-1.

[0102] The total arsenic content in the stems and leaves of rice seedlings was significantly reduced, with the total arsenic content at the stem base of seedlings treated with CK reaching 0.40 μg·kg⁻¹. -1 The cadmium content at the stem base of rice seedlings treated with OY-1 was 0.27 μg·kg⁻¹. -1 Compared with the CK treatment, the reduction was 34.08%. The three treatments, Y-1, Y-2, and Y-3, reduced OY-1 by 26.87%, 28.11%, and 29.60% respectively compared to the CK treatment, with no significant correlation between these three treatments and OY-1. The three treatments, Y-4, Y-5, and Y-6, reduced OY-1 by 7.71%, 10.20%, and 16.17% respectively compared to the CK treatment. None of these treatments showed a significant correlation with OY-1.

[0103] In the Y-7 and CK treatments, the total arsenic content in the roots and leaves of rice seedlings decreased, while the total arsenic content at the base of the seedling stem increased. Compared with the OY-1 treatment, the arsenic concentration at the base of the stem was lower, while the arsenic concentration in the roots and leaves was higher. The application of surfactants in combination with the solution can induce physiological responses in crops and increase solution penetration.

[0104] The above data indicate that spraying OY-1 can significantly reduce the stress effect of arsenic on rice seedlings. Based on this result, it is speculated that spraying the foliar inhibitor of this invention can downregulate the expression levels of genes encoding the Lsi1, Lsi2, and Lsi3 transporters, thereby reducing the stress of arsenic on rice roots. 3+ The absorption and transport capacity towards the central column are significantly reduced.

[0105] The above seedling stage test results prove that the foliar inhibitor provided by this invention contains small molecule organic raw materials such as SAC, DMSA and glycine. These small molecule organic substances can directly enter the crop and participate in the crop's metabolism. Therefore, when applied during the seedling stage, it can also play a role in inhibiting heavy metals, especially in inhibiting the transport of heavy metals from the roots to the stems and leaves. Therefore, the foliar inhibitor of this invention can improve the application window to the seedling to heading stage of rice, which can broaden the window period and solve the problems that existing foliar inhibitors can only be used in rice tillering-grain filling stage, have a short product window period, and are difficult to use due to weather conditions (usually rainy season).

[0106] III. Rice Pot Experiment

[0107] To verify the feasibility of the present invention, soil samples from the topsoil layer (0-20cm) were collected from paddy fields at the experimental demonstration base in Xinma Village, Majiahe Town, Zhuzhou City, Hunan Province, and a completely randomized block outdoor pot experiment was conducted.

[0108] Test soil: Soil samples from the 0-20cm topsoil layer were collected from paddy fields (N27°50′1.3″, E113°02′8.4″) at the experimental demonstration base in Xinma Village, Majiahe Town, Zhuzhou City, Hunan Province. The total cadmium content was 25.89 mg / kg, and the total arsenic content was 40.25 mg / kg, indicating cadmium-arsenic combined contamination. According to the "Soil Environmental Quality Standard for Agricultural Land Soil Pollution Risk Control (Trial)" (GB15618-2018), the As content was 1.3 times the risk screening level.

[0109] Table 6 Soil pH and Cd and As content.

[0110] soil 4.97±0.51 40.25±8.35 25.89±0.21 Risk screening value ＞5.5～6.5 Paddy ≤30.0 ≤0.3

[0111] Note: Data in the table are mean ± standard deviation (n=3)

[0112] Table 7. Treatment names and operating procedures for pot experiments

[0113] CK No materials are sprayed. QY-1 Apply 250 ml of the leaf surface inhibition and repair agent prepared in Example 1 to rice seedlings and tillering stages. QY-2 Apply 250 ml of the leaf surface inhibition and repair agent prepared in Example 2 to rice seedlings and tillering stages. QY-3 Apply 250 ml of the leaf surface inhibition and repair agent prepared in Example 3 to rice seedlings and tillering stages.

[0114] Before the rice pot experiment, soil samples were collected from the pots to determine the soil physicochemical properties. One week before transplanting, based on normal rice cultivation fertilization techniques and the conversion of pot soil surface area, base fertilizer (6.5g superphosphate, 6.5g urea, and 2g potassium nitrate) was evenly applied to the soil in each pot.

[0115] Rice roots, stems, leaves and rice grains were pulverized into powder samples using a high-speed pulverizer, and the samples were processed and measured in accordance with the "Determination of Total Arsenic and Inorganic Arsenic in Food" (GB 5009.11—2014).

[0116] The results of the study are analyzed as follows:

[0117] Table 8. Effects of different treatment groups of foliar inhibitory remediation agents on Cd and As content in brown rice.

[0118]

[0119] Note: Data in the table are mean ± standard deviation (n=3)

[0120] As shown in Table 8, compared with the control (CK) treatment, the cadmium reduction in brown rice of the OY-2, OY-3, and OY-4 treatment groups, which added the foliar inhibitor of this invention, reached 70.41%, 54.08%, and 64.28%, respectively, and the arsenic reduction reached 32.14%, 10.71%, and 17.85%, respectively, showing significant differences among the treatment groups. This demonstrates that the foliar inhibitor provided by this invention can significantly control the absorption and translocation of heavy metals such as cadmium and arsenic from the roots to the grains (rice) in rice.

[0121] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A heavy metal detoxifying organic foliar inhibitor, characterized in that, Including the following parts by weight of raw materials: SAC 15-30 portions; DMSA 15-30 servings; 15-30 parts glycine; 1-5 parts of surfactant, wherein the surfactant is sodium alkylbenzene sulfonate; 1-5 parts of ultraviolet light stabilizer, wherein the ultraviolet light stabilizer is a plant flavonoid; In preparation, SAC, DMSA and glycine are first prepared into solutions, and after thorough mixing, surfactants and ultraviolet light stabilizers are added to obtain the leaf surface resistance repair agent. The foliar inhibitor reduces the transport of heavy metals from the stem base to the leaves by accumulating heavy metals absorbed by the rice roots into the stem base.

2. A method for preparing the heavy metal detoxification organic foliar barrier repair agent as described in claim 1, characterized in that, Includes the following steps: S1. Prepare DMSA solution, SAC solution and glycine solution respectively, and then mix the three solutions thoroughly. S2. Next, adjust the pH of the mixed solution obtained in step S1 to 5-7. S3. Then add the surfactant, and finally add the UV stabilizer. Stir well to obtain the final product.

3. The preparation method according to claim 2, characterized in that, The DMSA solution in step S1 is prepared by the following method: DMSA is added to the first solvent and mixed according to the solid-liquid ratio of 1g:4~6mL, and ultrasonically dispersed for 30~40min to obtain the DMSA solution; the first solvent is dimethyl sulfoxide.

4. The preparation method according to claim 2, characterized in that, The SAC solution in step S1 is prepared by the following method: SAC is added to water and mixed according to a solid-liquid ratio of 1g: 9~11mL, heated to 60~70℃, stirred until dissolved, and cooled to obtain the solution.

5. The preparation method according to claim 2, characterized in that, The glycine solution in step S1 is prepared as follows: Glycine is added to water and mixed according to a solid-liquid ratio of 1g:9~11mL, heated to 60~70℃, stirred until dissolved, and cooled to obtain the solution.

6. The preparation method according to claim 2, characterized in that, The method further includes step S4, removing impurities and particles from the mixture obtained in step S3.

7. The preparation method according to claim 2, characterized in that, Step S2 involves adjusting the pH to 5-7 using acetic acid.

8. The application of the heavy metal detoxifying organic foliar barrier repair agent as described in claim 1 or the heavy metal detoxifying organic foliar barrier repair agent prepared by any of the preparation methods described in claims 2 to 7 is specifically to spray the heavy metal detoxifying organic foliar barrier repair agent on the leaves of rice from the seedling stage to the heading stage, so as to accumulate the heavy metals absorbed by the roots of rice into the stem base and reduce the translocation of heavy metals from the stem base to the stem and leaves.

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