Selenium-rich nutrient solution and application thereof in increasing selenium content of heavy metal antagonistic 409 small tomato

Abstract

The application discloses a selenium-rich nutrient solution and application thereof in improving selenium content of heavy metal antagonistic 409 small tomatoes. The selenium-rich nutrient solution comprises humic acid, fulvic acid, sodium alginate, complex hydrolytic biological enzyme, complex amino acid, calcium element, magnesium element, zinc element, boron element, manganese element, iron element, potassium element and sodium selenite. In the growth stage of the 409 small tomatoes, the selenium-rich nutrient solution is sprayed on the leaves by using a foliar spraying method. According to the method, the total selenium content in the 409 small tomato fruits is obviously improved by applying the selenium-rich nutrient solution with different concentrations, and the total selenium content in the 409 small tomato fruits is increased with the increase of the selenium concentration. According to the method, the content of heavy metal cadmium in the 409 small tomatoes is also obviously changed by applying the selenium-rich nutrient solution with different concentrations, and the content of the heavy metal cadmium in the 409 small tomato fruits is obviously reduced under a specific concentration.

Description

Technical Field

[0001] This invention relates to the field of agricultural cultivation technology, specifically to a selenium-enriched nutrient solution and its application in increasing the selenium content of heavy metal antagonistic 409 cherry tomatoes. Background Technology

[0002] Selenium (Se) is an essential micronutrient for humans and animals; both selenium deficiency and excess can negatively impact health. Selenium plays a vital role in antioxidation, regulating thyroid hormone metabolism, maintaining reproductive and neural development, and enhancing immune function. Long-term insufficient selenium intake can lead to weakened immunity, cognitive decline, and thyroid dysfunction, while excessive intake may damage the nervous system and increase the risk of metabolic diseases. Therefore, scientifically supplementing selenium through diet has become a research hotspot in the field of nutrition, and cultivating and developing selenium-enriched agricultural products is an important way to achieve safe and effective selenium supplementation.

[0003] Cadmium (Cd) is a heavy metal that can enter agricultural ecosystems through processes such as mining, wastewater irrigation, and the application of sludge and fertilizers containing metal. Cadmium is easily absorbed by plant roots and accumulates in crops, ultimately inhibiting plant growth and development. It can also affect animal and human health through the food chain. Therefore, reducing cadmium accumulation in crops is a key issue in environmental and agricultural science research.

[0004] Selenium (Se) can mitigate the toxic effects of cadmium (Cd) on plants by regulating the plant's antioxidant system, inhibiting cadmium absorption and transport, or reducing the bioavailability of Cd, thus forming a selenium-cadmium antagonistic effect. Therefore, combining this selenium-cadmium antagonistic effect with the study of how to enhance crops' resistance to heavy metal stress while enriching them with selenium is a major research topic in agricultural science.

[0005] Cherry tomatoes (Solanum lycopersicum var. cerasiforme) originated in South America and are an economically important crop used as both a fruit and vegetable. They are flavorful, nutritious, and have high nutritional value and market potential. The fruit is rich in lycopene, vitamin C, polyphenols, flavonols, soluble sugars, and various amino acids. Lycopene and polyphenols, in particular, have strong antioxidant activity and offer excellent nutritional and health benefits.

[0006] Dandong 409 cherry tomato is a specialty cherry tomato variety from Dandong, Liaoning Province. Influenced by local climate conditions and cultivation practices, it has developed a unique fruit shape and flavor. This variety has a strong ability to absorb and accumulate selenium. By adding inorganic selenium nutrient solution during hydroponics and foliar spraying with organic selenium fertilizer, the selenium content of the fruit can be effectively increased, achieving selenium-enriched production.

[0007] Studies have shown that appropriate concentrations of selenium treatment can not only increase the selenium content of Dandong 409 cherry tomatoes, but also reduce the accumulation of the heavy metal cadmium in them, optimize quality indicators such as soluble solids and organic acids, and promote yield to a certain extent. However, the type of selenium source and the application concentration both significantly affect the selenium enrichment effect in the fruit. Therefore, developing safe, efficient, and scalable selenium-enriched cultivation techniques is of significant theoretical and practical importance for promoting the high-quality, high-selenium production of Dandong 409 cherry tomatoes. Summary of the Invention

[0008] To address the aforementioned technical problems, the purpose of this invention is to provide a selenium-enriched nutrient solution and its application in increasing the selenium content of heavy metal antagonistic 409 cherry tomatoes. 409 cherry tomatoes cultivated using the method of this invention have a rich selenium content, significantly reduce the cadmium content in 409 cherry tomatoes, and improve fruit quality.

[0009] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is: a selenium-enriched nutrient solution, wherein the selenium-enriched nutrient solution comprises humic acid, fulvic acid, sodium alginate, compound hydrolytic enzyme, compound amino acids, calcium, magnesium, zinc, boron, manganese, iron, potassium and sodium selenite.

[0010] Furthermore, each liter of the selenium-enriched nutrient solution contains 20 g - 40 g of humic acid, 15 g - 35 g of fulvic acid, 2.0 g - 3.0 g of sodium alginate, 0.5 g - 1.5 g of compound hydrolytic enzyme, 100 g - 150 g of compound amino acids, 20 g - 40 g of calcium, 10 g - 30 g of magnesium, 0.2 g - 1.0 g of zinc, 0.3 g - 1.0 g of boron, 0.3 g - 1.0 g of manganese, 0.2 g - 1.0 g of iron, 40 g - 60 g of potassium, and 10 mg - 80 mg of sodium selenite.

[0011] Furthermore, each liter of the selenium-enriched nutrient solution contains 30 g of humic acid, 25 g of fulvic acid, 2.5 g of sodium alginate, 1.0 g of compound hydrolytic enzyme, 100 g of compound amino acids, 20 g of calcium, 10 g of magnesium, 0.2 g of zinc, 0.5 g of boron, 0.3 g of manganese, 0.2 g of iron, 40 g of potassium, and 40 mg of sodium selenite.

[0012] Furthermore, the complex hydrolytic enzyme includes cellulase and pectinase.

[0013] Furthermore, by mass ratio, cellulase:pectinase = 2:(0.5-1.5).

[0014] A method for preparing selenium-enriched nutrient solution, wherein each liter of selenium-enriched nutrient solution prepared includes the following steps:

[0015] (1) Preparation of matrix mixture: Add an appropriate amount of deionized water to a container, and slowly add humic acid, fulvic acid, sodium alginate and compound hydrolytic enzyme in sequence while stirring. Stir thoroughly until completely dispersed and dissolved to obtain matrix mixture.

[0016] (2) Preparation of macronutrient salt solutions: Take compound amino acids, calcium salts, magnesium salts and potassium salts respectively, dissolve them in an appropriate amount of deionized water to obtain compound amino acid solution, calcium element solution, magnesium element solution and potassium element solution respectively;

[0017] (3) Preparation of micronutrient salt solutions: Zinc salt, boron salt, manganese salt and iron salt were dissolved in an appropriate amount of deionized water to obtain zinc element solution, boron element solution, manganese element solution and iron element solution respectively;

[0018] (4) Preparation of sodium selenite solution: Dissolve sodium selenite in an appropriate amount of deionized water to obtain sodium selenite solution;

[0019] (5) While stirring, add the composite amino acid solution, calcium element solution, magnesium element solution and potassium element solution to the matrix mixture in sequence. After stirring continuously until uniform, add zinc element solution, boron element solution, manganese element solution and iron element solution. Continue stirring. Finally, add sodium selenite solution and stir thoroughly. Then, dilute to 1 L with deionized water.

[0020] This invention provides the application of a selenium-enriched nutrient solution in increasing the selenium content of heavy metal antagonist 409 cherry tomatoes.

[0021] A method for increasing the selenium content of heavy metal antagonistic 409 cherry tomatoes, the method comprising: during the growth stage of 409 cherry tomatoes, applying the above-mentioned selenium-enriched nutrient solution to the leaves by foliar spraying.

[0022] Furthermore, during the growth stages of the 409 cherry tomatoes, the above-mentioned selenium-enriched nutrient solution was sprayed on the leaves at four different stages: mid-fruit setting, late-fruit setting, fruit enlargement, and color change.

[0023] The beneficial effects of this invention are:

[0024] This invention significantly increased the total selenium content in 409 cherry tomato fruits by foliar spraying with selenium-enriched nutrient solution, and the total selenium content of 409 cherry tomato fruits increased with the increase of selenium concentration in foliar spraying. With the increase of selenium content, the application of different concentrations of selenium-enriched nutrient solution also significantly changed the content of the heavy metal cadmium in 409 cherry tomatoes. At a specific concentration, the content of heavy metal cadmium in 409 cherry tomato fruits was significantly reduced, while the photosynthetic intensity of 409 cherry tomatoes during growth was significantly increased. Attached Figure Description

[0025] Figure 1 The effect of different selenium concentrations of selenium-enriched nutrient solutions on the selenium content of 409 cherry tomato fruits.

[0026] Figure 2 The effect of different selenium concentrations of selenium-enriched nutrient solutions on the cadmium content of 409 cherry tomato fruits. Detailed Implementation

[0027] The present invention will be further described below with reference to the embodiments.

[0028] Example 1: Selenium-enriched nutrient solution

[0029] I. Composition of Selenium-Enriched Nutrient Solution

[0030] In this embodiment, each liter of selenium-enriched nutrient solution contains 30 g of humic acid, 25 g of fulvic acid, 2.5 g of sodium alginate, 1.0 g of compound hydrolytic enzyme, 100 g of compound amino acids, 20 g of calcium, 10 g of magnesium, 0.2 g of zinc, 0.5 g of boron, 0.3 g of manganese, 0.2 g of iron, 40 g of potassium, and 10 mg of sodium selenite.

[0031] The complex hydrolytic enzymes include cellulase and pectinase. The mass ratio of cellulase to pectinase is 2:1.

[0032] II. Preparation method of selenium-enriched nutrient solution:

[0033] (1) Preparation of matrix mixture:

[0034] Add 300 mL of deionized water to a beaker, and while stirring, slowly add 30 g of humic acid, 25 g of fulvic acid, 2.5 g of sodium alginate and 1.0 g of compound hydrolytic enzyme in sequence, stirring thoroughly until completely dispersed and dissolved to obtain a matrix mixture.

[0035] (2) Preparation of macronutrient salt solutions:

[0036] Compound amino acid solution: Dissolve 100.0 g of commercially available compound amino acid powder in 100 mL of deionized water by stirring.

[0037] Calcium elemental solution: Dissolve 117.9 g of calcium nitrate tetrahydrate in 100 mL of deionized water.

[0038] Magnesium elemental solution: Dissolve 83.7 g of magnesium chloride hexahydrate in 100 mL of deionized water.

[0039] Potassium elemental solution: Dissolve 103.4 g of potassium nitrate in 100 mL of deionized water.

[0040] (3) Preparation of micronutrient salt solutions:

[0041] Zinc elemental solution: Dissolve 1.5 g of EDTA-Zn in 30 mL of deionized water.

[0042] Boron solution: Dissolve 3 g of boric acid in 50 mL of hot water (about 60 °C) and cool to room temperature.

[0043] Manganese element solution: Dissolve 2.3 g of EDTA-Mn in 30 mL of deionized water.

[0044] Iron element solution: Dissolve 1.5 g of EDTA-Fe in 30 mL of deionized water.

[0045] (4) Preparation of sodium selenite solution:

[0046] Weigh 10 mg of anhydrous sodium selenite and dissolve it in 30 mL of deionized water.

[0047] (5) While stirring, add the composite amino acid solution, calcium element solution, magnesium element solution and potassium element solution to the matrix mixture in sequence. After stirring continuously until uniform, add zinc element solution, boron element solution, manganese element solution and iron element solution. Continue stirring. Finally, add sodium selenite solution and stir thoroughly. Then, dilute to 1L with deionized water.

[0048] Example 2: Selenium-enriched nutrient solution

[0049] I. Composition of Selenium-Enriched Nutrient Solution

[0050] In this embodiment, each liter of selenium-enriched nutrient solution contains 30 g of humic acid, 25 g of fulvic acid, 2.5 g of sodium alginate, 1.0 g of compound hydrolytic enzyme, 100 g of compound amino acids, 20 g of calcium, 10 g of magnesium, 0.2 g of zinc, 0.5 g of boron, 0.3 g of manganese, 0.2 g of iron, 40 g of potassium, and 20 mg of sodium selenite.

[0051] The complex hydrolytic enzymes include cellulase and pectinase. The mass ratio of cellulase to pectinase is 2:1.

[0052] II. Preparation method of selenium-enriched nutrient solution:

[0053] (1) Preparation of matrix mixture: Same as in Example 1.

[0054] (2) Preparation of constant nutrient salt solution: Same as in Example 1.

[0055] (3) Preparation of micronutrient salt solution: Same as in Example 1.

[0056] (4) Preparation of sodium selenite solution:

[0057] Weigh 20 mg of anhydrous sodium selenite and dissolve it in 30 mL of deionized water.

[0058] (5) While stirring, add the composite amino acid solution, calcium element solution, magnesium element solution and potassium element solution to the matrix mixture in sequence. After stirring continuously until uniform, add zinc element solution, boron element solution, manganese element solution and iron element solution. Continue stirring. Finally, add sodium selenite solution and stir thoroughly. Then, dilute to 1 L with deionized water.

[0059] Example 3: Selenium-enriched nutrient solution

[0060] I. Composition of Selenium-Enriched Nutrient Solution

[0061] In this embodiment, each liter of selenium-enriched nutrient solution contains 30 g of humic acid, 25 g of fulvic acid, 2.5 g of sodium alginate, 1.0 g of compound hydrolytic enzyme, 100 g of compound amino acids, 20 g of calcium, 10 g of magnesium, 0.2 g of zinc, 0.5 g of boron, 0.3 g of manganese, 0.2 g of iron, 40 g of potassium, and 40 mg of sodium selenite.

[0062] The complex hydrolytic enzymes include cellulase and pectinase. The mass ratio of cellulase to pectinase is 2:1.

[0063] II. Preparation method of selenium-enriched nutrient solution:

[0064] (1) Preparation of matrix mixture: Same as in Example 1.

[0065] (2) Preparation of constant nutrient salt solution: Same as in Example 1.

[0066] (3) Preparation of micronutrient salt solution: Same as in Example 1.

[0067] (4) Preparation of sodium selenite solution:

[0068] Weigh 40 mg of anhydrous sodium selenite and dissolve it in 50 mL of deionized water.

[0069] (5) While stirring, add the composite amino acid solution, calcium element solution, magnesium element solution and potassium element solution to the matrix mixture in sequence. After stirring continuously until uniform, add zinc element solution, boron element solution, manganese element solution and iron element solution. Continue stirring. Finally, add sodium selenite solution and stir thoroughly. Then, dilute to 1 L with deionized water.

[0070] Example 4: Selenium-enriched nutrient solution

[0071] I. Composition of Selenium-Enriched Nutrient Solution

[0072] In this embodiment, each liter of selenium-enriched nutrient solution contains 30 g of humic acid, 25 g of fulvic acid, 2.5 g of sodium alginate, 1.0 g of compound hydrolytic enzyme, 100 g of compound amino acids, 20 g of calcium, 10 g of magnesium, 0.2 g of zinc, 0.5 g of boron, 0.3 g of manganese, 0.2 g of iron, 40 g of potassium, and 80 mg of sodium selenite.

[0073] The complex hydrolytic enzymes include cellulase and pectinase. The mass ratio of cellulase to pectinase is 2:1.

[0074] II. Preparation method of selenium-enriched nutrient solution:

[0075] (1) Preparation of matrix mixture: Same as in Example 1.

[0076] (2) Preparation of constant nutrient salt solution: Same as in Example 1.

[0077] (3) Preparation of micronutrient salt solution: Same as in Example 1.

[0078] (4) Preparation of sodium selenite solution:

[0079] Weigh out 80 mg of anhydrous sodium selenite and dissolve it in 50 mL of deionized water.

[0080] (5) While stirring, add the composite amino acid solution, calcium element solution, magnesium element solution and potassium element solution to the matrix mixture in sequence. After stirring continuously until uniform, add zinc element solution, boron element solution, manganese element solution and iron element solution. Continue stirring. Finally, add sodium selenite solution and stir thoroughly. Then, dilute to 1 L with deionized water.

[0081] Example 5: Selenium-enriched nutrient solution

[0082] In this embodiment, each liter of selenium-enriched nutrient solution contains 40 g of humic acid, 35 g of fulvic acid, 3.0 g of sodium alginate, 1.5 g of compound hydrolytic enzyme, 150 g of compound amino acids, 40 g of calcium, 30 g of magnesium, 1.0 g of zinc, 1.0 g of boron, 1.0 g of manganese, 1.0 g of iron, 60 g of potassium, and 40 mg of sodium selenite.

[0083] The complex hydrolytic enzymes include cellulase and pectinase. The mass ratio of cellulase to pectinase is 2:1.

[0084] Example 6: Selenium-enriched nutrient solution

[0085] In this embodiment, each liter of selenium-enriched nutrient solution contains 20 g of humic acid, 15 g of fulvic acid, 2.0 g of sodium alginate, 0.5 g of compound hydrolytic enzyme, 120 g of amino acids, 30 g of calcium, 20 g of magnesium, 0.5 g of zinc, 0.3 g of boron, 0.5 g of manganese, 0.5 g of iron, 50 g of potassium, and 40 mg of sodium selenite.

[0086] The complex hydrolytic enzymes include cellulase and pectinase. The mass ratio of cellulase to pectinase is 2:1.

[0087] Example 7: Application of selenium-enriched nutrient solution in increasing selenium content in heavy metal antagonistic 409 cherry tomatoes

[0088] 1. Experimental varieties:

[0089] Dandong 409 cherry tomatoes.

[0090] 2. Experimental methods:

[0091] Soil: The cadmium concentration in the soil was found to be 1.71 mg / kg.

[0092] The experiment was conducted from September 2025 to January 2026 in the ecological greenhouse of Liaoning University, Shenyang, Liaoning Province. Ten pots of the 409 cherry tomato variety were cultivated and randomly divided into a blank control group and four experimental treatment groups, with two pots in each group and three 409 cherry tomato plants in each pot. Routine management was carried out as usual. During the growth stages of the 409 cherry tomato, at the mid-fruit setting stage, late-fruit setting stage, fruit enlargement stage, and color change stage, the experimental treatment groups were foliar sprayed with selenium-enriched nutrient solutions prepared in Examples 1-4 (denoted as: T1 - Example 1 - sodium selenite content 10 mg / L; T2 - Example 2 - sodium selenite content 20 mg / L; T3 - Example 3 - sodium selenite content 40 mg / L; T4 - Example 4 - sodium selenite content 80 mg / L). The blank control group was foliar sprayed with an equal amount of water (denoted as: CK - blank - water). After harvesting the fruit in January, the total selenium and cadmium content of the fruit were tested. The results are as follows: Figure 1 and Figure 2 .

[0093] Determination of total selenium content: The selenium content was determined according to the national standard GB / T 5009.93-2017 "National Food Safety Standard - Determination of Selenium in Food" by hydride atomic fluorescence spectrometry.

[0094] Determination of total cadmium content: Cadmium content was determined according to GB 5009.15-2023 "National Food Safety Standard - Determination of Cadmium in Food" - Inductively Coupled Plasma Mass Spectrometry.

[0095] 3. Results:

[0096] like Figure 1 As shown, different selenium concentrations significantly increased the total selenium content in 409 cherry tomato fruits. With the increase of selenium content in the selenium-enriched nutrient solution, the total selenium content in 409 cherry tomato fruits also increased with the increase of foliar spray selenium concentration. The total selenium content in the T4 treatment group reached the maximum value (10.27 mg / kg), which was 6.3 times that of the T1 group (1.63 mg / kg) and 153.28 times that of the CK group (0.067 mg / kg).

[0097] like Figure 2 As shown, with the increase of selenium content in the selenium-enriched nutrient solution, the cadmium content in the 409 cherry tomato fruits showed a trend of first rising, then falling, and then rising again. The cadmium content in the T3 treatment group reached the lowest value (0.03 mg / kg).

[0098] During the experiment, the leaves of the T4 treatment group all showed signs of selenium poisoning, with yellow spots, wilting, and curling. The fruit biomass was also generally lower than that of the T3 treatment group. In the T3 treatment group, the selenium concentration of the fruit was 4.21 mg / kg and the cadmium concentration was 0.03 mg / kg.

[0099] 4. Effects of applying selenium-enriched nutrient solution on photosynthesis in leaves of 409 cherry tomatoes

[0100] Instruments used: Chlorophyll meter (Yaxin-1260, Beijing Yaxin Instrument Technology Co., Ltd.), Photosynthesis meter (Model 3051C, Zhejiang Top Cloud-Agri Technology Co., Ltd.). Relevant parameters are as follows:

[0101] External carbon dioxide concentration: 505.0 ppm - 525.9 ppm;

[0102] Ambient temperature: 20.5 ℃ - 20.9 ℃;

[0103] Leaf chamber temperature: 20℃ - 25℃;

[0104] Leaf chamber humidity: 54.5% - 68.5%;

[0105] The photosynthetic index of leaves was measured during the fruit enlargement period and the rapid growth period of leaves. The measurement time was 4 pm, and the results are shown in Table 1.

[0106]

[0107] As shown in Table 1, compared with the control group (CK), the application of selenium fertilizer (T3) increased the photosynthetic intensity of leaves. After the application of selenium fertilizer, the chlorophyll content of the 409 cherry tomato plants increased to 6.57 mg·m³. -2 The transpiration rate was 5.84 μmol·m -2 ·s-1 Photosynthetic rate and blank group (14.33 μmol·m -2 ·s -1 The ratio increased to 21.66 μmol·m -2 ·s -1 This indicates that applying selenium fertilizer can enhance the photosynthesis of 409 cherry tomatoes, which may increase the plant's growth rate or fruit yield.

Claims

1. A selenium-enriched nutrient solution, characterized in that, The selenium-enriched nutrient solution includes humic acid, fulvic acid, sodium alginate, compound hydrolytic enzymes, compound amino acids, calcium, magnesium, zinc, boron, manganese, iron, potassium, and sodium selenite.

2. The selenium-enriched nutrient solution according to claim 1, characterized in that, Each liter of the selenium-enriched nutrient solution contains 20 g - 40 g of humic acid, 15 g - 35 g of fulvic acid, 2.0 g - 3.0 g of sodium alginate, 0.5 g - 1.5 g of compound hydrolytic enzymes, 100 g - 150 g of compound amino acids, 20 g - 40 g of calcium, 10 g - 30 g of magnesium, 0.2 g - 1.0 g of zinc, 0.3 g - 1.0 g of boron, 0.3 g - 1.0 g of manganese, 0.2 g - 1.0 g of iron, 40 g - 60 g of potassium, and 10 mg - 80 mg of sodium selenite.

3. The selenium-enriched nutrient solution according to claim 2, characterized in that, Each liter of the selenium-enriched nutrient solution contains 30 g of humic acid, 25 g of fulvic acid, 2.5 g of sodium alginate, 1.0 g of compound hydrolytic enzyme, 100 g of compound amino acids, 20 g of calcium, 10 g of magnesium, 0.2 g of zinc, 0.5 g of boron, 0.3 g of manganese, 0.2 g of iron, 40 g of potassium, and 40 mg of sodium selenite.

4. A selenium-enriched nutrient solution according to claim 1, 2, or 3, characterized in that, The complex hydrolytic enzymes include cellulase and pectinase.

5. The selenium-enriched nutrient solution according to claim 4, characterized in that, The mass ratio of cellulase to pectinase is 2:(0.5-1.5).

6. A method for preparing a selenium-enriched nutrient solution according to any one of claims 1-5, characterized in that, The preparation method for each liter of selenium-enriched nutrient solution includes the following steps: (1) Preparation of matrix mixture: Add an appropriate amount of deionized water to a container, and slowly add humic acid, fulvic acid, sodium alginate and compound hydrolytic enzyme in sequence while stirring. Stir thoroughly until completely dispersed and dissolved to obtain matrix mixture. (2) Preparation of macronutrient salt solutions: Take compound amino acids, calcium salts, magnesium salts and potassium salts respectively, dissolve them in an appropriate amount of deionized water to obtain compound amino acid solution, calcium element solution, magnesium element solution and potassium element solution respectively; (3) Preparation of micronutrient salt solutions: Zinc salt, boron salt, manganese salt and iron salt were dissolved in an appropriate amount of deionized water to obtain zinc element solution, boron element solution, manganese element solution and iron element solution respectively; (4) Preparation of sodium selenite solution: Dissolve sodium selenite in an appropriate amount of deionized water to obtain sodium selenite solution; (5) While stirring, add the composite amino acid solution, calcium element solution, magnesium element solution and potassium element solution to the matrix mixture in sequence. After stirring continuously until uniform, add zinc element solution, boron element solution, manganese element solution and iron element solution. Continue stirring. Finally, add sodium selenite solution and stir thoroughly. Then, dilute to 1 L with deionized water.

7. The application of the selenium-enriched nutrient solution according to any one of claims 1-5 in increasing the selenium content of heavy metal antagonistic 409 cherry tomatoes.

8. A method for increasing the selenium content of heavy metal antagonist 409 cherry tomatoes, characterized in that, The method includes: during the growth stage of 409 cherry tomatoes, spraying the leaves with the selenium-enriched nutrient solution as described in any one of claims 1-5.

9. A method for increasing the selenium content of heavy metal antagonist 409 cherry tomatoes according to claim 8, characterized in that, During the growth stages of the 409 cherry tomato, the selenium-enriched nutrient solution described in any one of claims 1-5 is sprayed on the leaves at four different periods; the four periods refer to the mid-fruit setting stage, the late-fruit setting stage, the fruit enlargement stage, and the color change stage.

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