An organic selenium and heavy metal foliar control agent and its application

Abstract

The present invention discloses an organic selenium heavy metal foliar barrier, which contains: selenocyanate organic selenium and thiocyanate. The foliar barrier based on selenocyanate organic selenium disclosed by the present invention is less toxic than inorganic selenium, has a large plant tolerance, and plants can absorb and utilize a higher content of selenium, and the heavy metal antagonism effect is better; at the same time, after the divalent selenium element is absorbed by the plant, it directly participates in the physiological activities of the plant, is beneficial to the conversion of plant selenoproteins, and improves the utilization rate of selenium. The present invention adopts thiocyanate as a promoter, which can greatly improve the antagonistic effect of selenocyanate organic selenium on heavy metals in crops.

Description

Technical Field

[0001] The invention belongs to the technical field of fertilizers, and in particular relates to an organic selenium heavy metal foliar barrier and control agent and application thereof. Background Art

[0002] Selenium is an essential trace element for humans and animals and a beneficial nutrient for plants. It constitutes selenium-containing proteins and enzymes in the human body and is a component of glutathione peroxidase. Selenium is also a multifunctional life nutrient with antioxidant, anti-aging, anti-tumor, cell protection and repair, human immunity enhancement, and heavy metal poisoning. Studies have shown that selenium can promote the formation of antioxidant substances in crops, increase their resistance to harmful substances such as heavy metals, reduce the absorption of heavy metals, and reduce the accumulation of heavy metals in plants. Selenium may also promote the removal of heavy metals from metabolically active cell sites in crops or affect the transport of heavy metals in the body by changing the permeability of cell membranes to heavy metals.

[0003] Using physiological barriers on crop leaves 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 transfer of heavy metals to the food chain by precipitating or chelating heavy metals on the cell walls of crops and improving the resistance of crops to heavy metals. This technology is favored by domestic researchers because of its advantages such as low cost, environmental friendliness and convenient operation. At present, in the research on selenium as a plant nutrient and heavy metal barrier, most of the inorganic selenium compounds such as sodium selenite, sodium selenate and potassium selenate are used as selenium sources. Inorganic selenium itself has strong toxic side effects. Inorganic selenium compounds such as sodium selenite are hazardous chemicals, and there are safety hazards in production and use. With the deepening of research and people's actual use, it is found that crops have limited tolerance to inorganic selenium compounds. Using too high a concentration will cause crop poisoning, such as yellowing of leaves, fruit falling during fruiting period, and reduced grain production. At the same time, there is a risk of excessive inorganic selenium residues in agricultural products. In summary, the inorganic selenium compounds used in the prior art have high biological toxicity and limited plant tolerance, which limits the plant's ability to absorb high levels of selenium, thereby limiting the plant's ability to antagonize heavy metals. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a heavy metal foliar inhibitor with low toxicity and good water solubility using an organic selenium cyanide compound as a selenium source, so as to improve the tolerance of plants to selenium and enhance the antagonism of selenium to heavy metals in crops, while avoiding the residues of inorganic selenium in crops and personal safety issues during use.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The invention provides an organic selenium heavy metal foliage control agent, which contains selenocyanate organic selenium and thiocyanate.

[0007] Preferably, the selenocyanate organic selenium is a combination of one or more of selenocyanate organic acid salts, selenocyanate esters, and polyselenocyanate organic selenium compounds.

[0008] Preferably, the selenium cyanide organic selenium is a combination of one or more of potassium selenocyanoacetate, sodium selenocyanoacetate, benzyl selenium cyanide, and phenyldimethyl selenium cyanide.

[0009] Preferably, the thiocyanate is a combination of one or more of potassium thiocyanate, ammonium thiocyanate and sodium thiocyanate.

[0010] Preferably, the organic selenium and heavy metal foliage control agent further contains a surfactant.

[0011] The present invention also provides the use of the organic selenium heavy metal foliar barrier in reducing the heavy metal content of crops, wherein the crops are seed crops, bulb crops or root crops.

[0012] Preferably, the organic selenium and heavy metal foliar control agent is applied by diluting it with water and then spraying it on the leaves.

[0013] Preferably, the organic selenium and heavy metal foliar inhibitor is sprayed during at least one of the flowering, fruiting, filling and swelling periods of crops, and the number of spraying times is 2 to 3 times.

[0014] The invention also provides the use of thiocyanate in improving the antagonistic effect of selenocyanate organic selenium on heavy metals in crops.

[0015] Preferably, in the application, the molar ratio of sulfur to selenium of the thiocyanate and selenocyanate organic selenium is 1:0.5-1.5.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The foliar barrier agent based on selenocyanate organic selenium provided by the present invention is less toxic than inorganic selenium, has a larger plant tolerance, and can absorb and utilize higher levels of selenium, with better heavy metal antagonism effect; at the same time, after being absorbed by plants, the -2 valent selenium directly participates in plant physiological activities, is beneficial to the conversion of plant selenoproteins, and improves the utilization rate of selenium.

[0018] (2) The present invention uses thiocyanate as a promoter, which can greatly improve the antagonistic effect of selenocyanate organic selenium on heavy metals in crops. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can more clearly understand the present invention. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. In the embodiments of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; unless otherwise specified, the technical means used are conventional means well known to those skilled in the art.

[0020] The embodiment of the present invention provides an organic selenium heavy metal foliage control agent, which contains: selenocyanate organic selenium and thiocyanate.

[0021] Selenium cyanide organic selenium refers to a class of organic selenium compounds containing a selenocyanide functional group (-SeCN). Selenium compounds contain a variety of valence states such as -2, 0, +2, +4, and +6. After being absorbed into the plant body through the roots or leaves of the plant, selenium compounds react with various enzymes, and the high-valent selenium is eventually reduced to a -2 valence state, participating in plant life activities, and partially converted into selenoamino acids or selenoproteins, which remain in the plant body, and a small amount is converted into selenoether substances, which are lost to the air or soil through plant respiration and transpiration. The reduction of selenium from a high-valent state to a low-valent state in the plant body is a difficult process, and some selenium elements that cannot be reduced will be transported back to the soil by transport proteins. As a result, the conversion rate of 0, +2, and +4 equivalent states of selenium in the plant body is not high, and the utilization rate of the foliar barrier agent containing this type of inorganic selenium is low. The valence of selenium in selenocyanate organic selenium is -2. After being absorbed by plants, it can directly participate in plant physiological activities, which is beneficial to the conversion of plant selenoproteins and improves the utilization rate of selenium.

[0022] In some preferred embodiments, the selenocyanate organic selenium is a combination of one or more of selenocyanate organic acid salts, selenocyanate esters, and polyselenocyanate organic selenium compounds.

[0023] In some preferred embodiments, the selenocyanate organic selenium is a combination of one or more of potassium selenocyanate acetate, sodium selenocyanate acetate, benzyl selenonocyanate, and phenyldimethyl selenonocyanate.

[0024] In some preferred embodiments, the thiocyanate is a combination of one or more of potassium thiocyanate, ammonium thiocyanate, and sodium thiocyanate.

[0025] In some preferred embodiments, it further contains a surfactant, such as sodium dodecyl sulfate.

[0026] In some preferred embodiments, the concentration of selenocyanate organic selenium is 10-25 g / L, the concentration of thiocyanate is 5-10 g / L, and the concentration of surfactant is 2-5 g / L.

[0027] The embodiments of the present invention also provide the use of the above-mentioned organic selenium heavy metal foliar inhibitor in reducing the heavy metal content of crops, wherein the crops are seed crops, bulb crops or root crops, such as rice, wheat, soybeans, corn, potatoes, tomatoes, garlic, etc.

[0028] In some preferred embodiments, the organic selenium and heavy metal foliar control agent is applied by diluting it with water and then spraying it on the leaves. One part of the organic selenium and heavy metal foliar control agent is diluted with 250 to 500 parts of water.

[0029] In some preferred embodiments, the organic selenium and heavy metal foliar inhibitor is sprayed during at least one of the flowering, fruiting, filling and swelling periods of the crops, and the number of spraying times is 2 to 3 times.

[0030] The embodiment of the present invention also provides the use of thiocyanate in improving the antagonistic effect of selenocyanate organic selenium on heavy metals in crops.

[0031] In some preferred embodiments, the molar ratio of sulfur to selenium in thiocyanate and selenocyanate organic selenium is 1:0.5-1.5.

[0032] Example 1

[0033] In this embodiment, heavy metal contaminated soil was collected from a certain place in Hubei Province, and potted garlic was used for experiments. The pH of the experimental soil was 5.33, and the excessive element contents were: cadmium 1.412 mg / kg, arsenic 113.6 mg / kg.

[0034] Specific experimental design: The collected heavy metal contaminated soil was naturally air-dried, crushed, sieved through a 2mm sieve, and mixed. Take several 30*50cm trays, and put 10kg of soil in each pot. Plant 20 garlic plants in each tray, and manage water and fertilizer according to conventional planting. Spray heavy metal foliar barrier agents once during the garlic stalk elongation period and bulb expansion period, respectively. Dilute 1 part of heavy metal foliar barrier agent with 400 parts of water, stir evenly, and use a sprayer to evenly spray on the leaves of garlic plants. After the garlic matures, take the garlic heads for detection and analysis to determine the content of heavy metal elements. The experimental test results are shown in Table 1. S1-1 to S1-4 are experimental groups, D1-1 to D1-8 are control groups, and D1-8 is a blank control group.

[0035] Preparation of the organic selenium foliar inhibitor in the experimental group: Take 1000 parts by weight of pure water, heat it to 50°C, add 20 parts by weight of organic selenium cyanide compounds, 8 parts by weight of thiocyanate, and 4 parts by weight of sodium dodecyl sulfate in sequence, stir to dissolve, and keep warm for 2 hours to obtain the organic selenium foliar inhibitor.

[0036] Preparation of the organic selenium foliar inhibitor in the control group: Take 1000 parts by weight of pure water, heat it to 50°C, add 20 parts by weight of organic selenium cyanide compounds and 4 parts by weight of sodium dodecyl sulfate in sequence, stir to dissolve, and keep warm for 2 hours to obtain the organic selenium foliar inhibitor.

[0037] Preparation of the inorganic selenium foliar inhibitor in the control group: take 1000 parts by weight of pure water, heat it to 50°C, add 20 parts by weight of an inorganic selenium compound, 8 parts or 0 parts by weight of thiocyanate, and 4 parts by weight of sodium dodecyl sulfate in sequence, stir to dissolve, and keep warm for 2 hours to obtain the inorganic selenium foliar inhibitor.

[0038] Table 1

[0039] Experiment number Foliar control agent ingredients Cadmium content (mg / kg) Arsenic content (mg / kg) S1-1 Sodium selenocyanoacetate + potassium thiocyanate 0.371 0.476 S1-2 Benzyl selenocyanate + potassium thiocyanate 0.355 0.416 S1-3 Potassium selenocyanate + potassium thiocyanate 0.343 0.388 S1-4 Potassium selenocyanate + ammonium thiocyanate 0.331 0.412 D1-1 Sodium selenocyanoacetate 0.457 0.543 D1-2 Benzyl selenyl cyanide 0.448 0.529 D1-3 Potassium selenocyanoacetate 0.427 0.541 D1-4 Sodium selenate + potassium thiocyanate 0.477 0.606 D1-5 Sodium selenate 0.484 0.591 D1-6 Sodium selenite + potassium thiocyanate 0.463 0.629 D1-7 Sodium selenite 0.455 0.642 D1-8 - 0.524 0.712

[0040] As can be seen from Table 1, the antagonistic effect of heavy metal foliar control agents using only organic selenium cyanide compounds as selenium sources on crop heavy metals is not significantly improved compared to inorganic selenium compounds. Using thiocyanate as a promoter has no obvious effect on inorganic selenium foliar control agents, but greatly improves the antagonistic effect of organic selenium cyanide compounds on crop heavy metals, among which the antagonistic effect on cadmium is increased by 18.8% to 22.5%, and the antagonistic effect on arsenic is increased by 12.3% to 28.3%.

[0041] Example 2

[0042] In this embodiment, heavy metal contaminated soil was collected from a place in Hubei Province, and soybeans were used for experiments. The pH of the experimental soil was 5.33, and the excessive element contents were: cadmium 1.412 mg / kg, arsenic 113.6 mg / kg.

[0043] Specific experimental design: The collected heavy metal contaminated soil was naturally air-dried, crushed, sieved with 2mm, and mixed. Take several 30*50cm trays, and put 10kg of soil in each pot. Plant 5 soybeans in each tray, and manage water and fertilizer according to conventional planting. Spray heavy metal foliar inhibitors once in the pod-setting period and once in the expansion period of soybeans. Dilute 1 part of heavy metal foliar inhibitors with 400 parts of water, stir evenly, and use a sprayer to evenly spray on the leaves of soybean plants. After the soybeans mature, take the soybeans for testing and analysis to determine the content of heavy metal elements. The experimental test results are shown in Table 2. S2-1 to S2-4 are experimental groups, D2-1 to D2-8 are control groups, and D2-8 is a blank control group.

[0044] Preparation of the organic selenium foliar inhibitor in the experimental group: Take 1000 parts by weight of pure water, heat it to 50°C, add 25 parts by weight of organic selenium cyanide compounds, 10 parts by weight of thiocyanate, and 5 parts by weight of sodium dodecyl sulfate in sequence, stir to dissolve, and keep warm for 2 hours to obtain the organic selenium foliar inhibitor.

[0045] Preparation of the organic selenium foliar inhibitor in the control group: Take 1000 parts by weight of pure water, heat it to 50°C, add 25 parts by weight of organic selenium cyanide compounds and 5 parts by weight of sodium dodecyl sulfate in sequence, stir to dissolve, and keep warm for 2 hours to obtain the organic selenium foliar inhibitor.

[0046] Preparation of the inorganic selenium foliar inhibitor in the control group: take 1000 parts by weight of pure water, heat it to 50°C, add 25 parts by weight of an inorganic selenium compound, 10 parts or 0 parts by weight of thiocyanate, and 5 parts by weight of sodium dodecyl sulfate in sequence, stir to dissolve, and keep warm for 2 hours to obtain the inorganic selenium foliar inhibitor.

[0047] Table 2

[0048] Experiment number Foliar control agent ingredients Cadmium content (mg / kg) Arsenic content (mg / kg) S2-1 Sodium selenocyanoacetate + potassium thiocyanate 0.389 0.504 S2-2 Benzyl selenocyanate + potassium thiocyanate 0.468 0.521 S2-3 Potassium selenocyanate + potassium thiocyanate 0.446 0.475 S2-4 Potassium selenocyanate + ammonium thiocyanate 0.427 0.494 D2-1 Sodium selenocyanoacetate 0.606 0.782 D2-2 Benzyl selenyl cyanide 0.589 0.741 D2-3 Potassium selenocyanoacetate 0.644 0.713 D2-4 Sodium selenate + potassium thiocyanate 0.655 0.778 D2-5 Sodium selenate 0.651 0.793 D2-6 Sodium selenite + potassium thiocyanate 0.618 0.811 D2-7 Sodium selenite 0.637 0.827 D2-8 - 0.702 1.211

[0049] As can be seen from Table 2, the heavy metal foliar barrier agent using only organic selenium cyanide compounds as selenium source has less obvious antagonistic effect on crop heavy metals than inorganic selenium compounds. Using thiocyanate as a promoter has no obvious effect on inorganic selenium foliar barrier agents, but greatly improves the antagonistic effect of organic selenium cyanide compounds on crop heavy metals, among which the antagonistic effect on cadmium is increased by 20.5% to 35.8%, and the antagonistic effect on arsenic is increased by 29.6% to 35.5%.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An organic selenium heavy metal foliar control agent, characterized in that: Containing: selenocyanate organic selenium and thiocyanate, wherein the weight fraction ratio of the selenocyanate organic selenium to thiocyanate is 5:2; The selenium cyanide organic selenium is potassium selenocyanoacetate, sodium selenocyanoacetate or benzyl selenium cyanide; The thiocyanate is a combination of one or more of potassium thiocyanate, ammonium thiocyanate and sodium thiocyanate.

2. The organic selenium heavy metal foliage control agent according to claim 1, characterized in that: It also contains surfactants.

3. Use of the organic selenium heavy metal foliar barrier agent according to claim 1 or 2 in reducing the heavy metal content of crops, characterized in that: The crops are seed crops, bulb crops or root crops.

4. The use according to claim 3, characterized in that: The organic selenium and heavy metal foliar control agent is applied by spraying on the leaves after being diluted with water.

5. The use according to claim 4, characterized in that: The spraying period of the organic selenium and heavy metal foliar inhibitor is at least one of the flowering period, fruiting period, grain filling period and swelling period of the crops, and the spraying frequency is 2 to 3 times.

6. Use of the organic selenium and heavy metal foliar barrier according to any one of claims 1 to 2, or the organic selenium and heavy metal foliar barrier in the application according to any one of claims 3 to 5 for antagonizing heavy metals in crops.