Chitosan functionalized nano-selenium fertilizer and its application

Abstract

The invention relates to the field of agriculture, and in particular to a chitosan functionalized nano-selenium fertilizer and an application thereof. The components of the nano-selenium fertilizer composition and their weight percentages are: 0.5-4.0% chitosan functionalized nano-selenium; 0.8-3.2% ectoine; 0-3.0% alginate; 0.5-5.0% surfactant; and the balance of deionized water. The invention has been found through experiments that in the composition of the invention, ectoine can significantly promote the absorption of chitosan functionalized nano-selenium by plants and promote the enrichment of selenium in plants, and the use of alginate can further increase the promoting effect of ectoine on the absorption and enrichment of nano-selenium by plants, thereby producing a synergistic effect.

Description

Technical Field

[0001] The invention relates to the field of agriculture, and in particular to a chitosan functionalized nano-selenium fertilizer and application thereof in the production of selenium-enriched tea. Background Art

[0002] Selenium is an important component of some antioxidant enzymes and selenoproteins in animals and humans. It plays a role in balancing the redox atmosphere in the body. Studies have shown that it can improve animal immunity. Nano-selenium also has broad application prospects in agriculture and other fields. The biological effects of selenium in plants are very significant, including promoting plant growth, increasing yields, and offsetting oxidative stress induced by various non-biological factors. At present, in tea planting technology, research is constantly being conducted on how to plant selenium-rich tea to achieve better health value of tea.

[0003] CN111848303A discloses that a chitosan functionalized nano-selenium composite bacterial enzyme system can be used to improve the yield and quality of tea, which is specifically manifested in significantly increasing the yield of tea, increasing the content of phenols, flavonoids and tea aroma substances in tea, reducing the bitter taste, enhancing the antioxidant property of tea, effectively improving the tea's resistance to brewing, improving the content levels of substances such as protein, tea polyphenols, total flavonoids and vitamin C in tea, and increasing the content of nutrients in tea.

[0004] However, how to better promote the absorption of nano-selenium by plants and improve its bioavailability has always been a topic of continuous research. Summary of the invention

[0005] The purpose of the present application is to provide a chitosan functionalized nano-selenium fertilizer composition, which can significantly promote the absorption of selenium by plants and improve its bioavailability after application, and can be used to produce selenium-enriched products, especially selenium-enriched tea.

[0006] One aspect of the present invention relates to a chitosan functionalized nano-selenium fertilizer composition, wherein the components of the composition and their weight percentages are:

[0007] Chitosan functionalized nano-selenium, 0.5-4.0%

[0008] Ectohydropyrimidine, 0.8-3.2%

[0009] Alginic acid, 0-3.0%

[0010] Surfactant, 0.5-5.0%

[0011] Deionized water, balance.

[0012] In the chitosan functionalized nano-selenium fertilizer composition of the present invention, the chitosan functionalized nano-selenium is prepared by the following method:

[0013] (1) Mix a sodium selenite solution with a concentration of 10-30 mmol / L and a potassium iodide solution with a concentration of 20-40 mmol / L at a ratio of 1:1 (v / v), add 20-40 (v / v) times the amount of water as the sodium selenite solution, and stir evenly;

[0014] (2) adding an equal volume of ascorbic acid solution with a concentration of 50-70 mmol / L to the sodium selenite solution and reacting for 20-40 minutes;

[0015] (3) After aging for 24 hours, a light red transparent colloidal solution was obtained;

[0016] (4) Centrifuge at 8000-10000 rpm for 20-40 min to remove the supernatant, and wash with water and alcohol to remove unreacted impurities;

[0017] (5) The nano-selenium particles were redispersed into an equal amount of sol, and a chitosan solution with a concentration of 0.32-0.64 mg / mL and an equal volume of sodium selenite solution was added to obtain a chitosan-functionalized nano-selenium complex.

[0018] The average molecular weight of chitosan is not particularly limited, for example, 5-100 KD, preferably 10-50 KD.

[0019] In the chitosan functionalized nano-selenium fertilizer composition of the present invention,

[0020] The content range of the chitosan functionalized nano-selenium is 0.5-4.0%, for example, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, and 4.0% can be selected.

[0021] The content range of the ectoine is 0.8-3.2%, for example, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, and 3.2% can be selected.

[0022] The content range of alginate is 1.5-3.0%, for example, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, and 3.0% can be selected.

[0023] The surfactant is a nonionic surfactant, and in some embodiments, is selected from one or more of nonylphenol polyoxyethylene ether, trisiloxane polyoxyethylene ether, fatty alcohol polyoxyethylene ether, fatty alcohol polyoxyethylene ether phosphate, glycerol fatty acid polyoxyethylene ether, castor oil polyoxyethylene ether, polyoxyethylene alkyl aryl ether, triphenyl ethyl phenol polyoxyethylene ether, polyoxyethylene lanolin alcohol, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene glyceryl mono fatty acid ester, and polyoxyethylene alkylamine. Preferably, it is one or more of nonylphenol polyoxyethylene ether, trisiloxane polyoxyethylene ether, castor oil polyoxyethylene ether, and polyoxyethylene lanolin alcohol.

[0024] The content range of the surfactant is 0.5-5.0%, for example, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, and 5.0% can be selected.

[0025] In one embodiment of the present invention, the components and their weight percentages in the chitosan functionalized nano-selenium fertilizer composition are preferably:

[0026] Chitosan functionalized nano-selenium, 1.5-3.0%

[0027] Ectoin, 1.2-2.4%

[0028] Alginic acid, 2.0-2.6%

[0029] Surfactants, 2.4-4.0%

[0030] Deionized water, balance.

[0031] In the present invention, it is found through experiments that the tetrahydropyrimidine can significantly promote the absorption of chitosan functionalized nano-selenium by plants and promote the enrichment of selenium in plants. Moreover, alginic acid can further increase the promoting effect of tetrahydropyrimidine on plant absorption and enrichment of nano-selenium. This effect is specifically manifested in that when chitosan functionalized nano-selenium and tetrahydropyrimidine are co-applied to plants, the selenium content in the plants is significantly increased compared to the use of chitosan functionalized nano-selenium alone. Further, when chitosan functionalized nano-selenium, tetrahydropyrimidine and alginic acid are applied simultaneously, the selenium content in the plants increases more significantly. In other words, alginate and tetrahydropyrimidine have a synergistic effect in promoting the absorption of selenium by plants. This is very beneficial for the production of selenium-enriched agricultural and sideline products.

[0032] In the present invention, the application objects of the chitosan functionalized nano-selenium fertilizer composition include those plants that need to obtain selenium-enriched products, preferably tea leaves.

[0033] Another aspect of the present invention relates to a method for preparing the chitosan functionalized nano-selenium fertilizer composition, which comprises the following steps:

[0034] (1) Weigh the formulated amount of surfactant and add it to the formulated amount of deionized water and mix well;

[0035] (2) Then, add the formulated amount of alginate and stir evenly;

[0036] (3) Then, add the formulated amount of ectoine and stir evenly;

[0037] (4) Finally, add the formulated amount of chitosan functionalized nano-selenium and stir evenly to obtain the product.

[0038] Another aspect of the present invention relates to a method for increasing the selenium content in plants, which comprises applying the chitosan functionalized nano-selenium fertilizer composition of the present invention to the plants.

[0039] In the above method described in the present invention, the plants include those plants for obtaining selenium-enriched products, preferably tea leaves.

[0040] In the above method described in the present invention, the application method includes contacting the chitosan functionalized nano-selenium fertilizer composition with plants, preferably by spraying.

[0041] The specific application time can be determined according to different plants, provided that the required selenium-enriched product is applied before harvest. When the plant is tea, it is preferred to spray the chitosan functionalized nano-selenium fertilizer composition of the present invention 45-60 days before picking, spraying 3-5 times in total, with an interval of 6-10 days between two sprayings. The dilution multiple of the agent is 500-1000 times, and the amount of liquid sprayed each time is controlled to be 30-60 L / mu.

[0042] Another aspect of the present invention relates to the use of the chitosan functionalized nano-selenium fertilizer composition for increasing the absorption and / or enrichment of selenium by plants.

[0043] In some embodiments, the chitosan functionalized nano-selenium fertilizer composition is used to increase the selenium content in plants.

[0044] In some embodiments, the present invention provides the use of ectoine or a combination of ectoine and alginate for increasing the absorption and / or enrichment of selenium in plants, which comprises applying ectoine or a combination of ectoine and alginate together with chitosan functionalized nano-selenium to plants.

[0045] In the above application of the present invention, the plants include those plants that need to obtain selenium-enriched products, preferably tea leaves.

[0046] In the above application of the present invention, the application method includes contacting the chitosan functionalized nano-selenium fertilizer composition with plants, preferably by spraying.

[0047] The specific application time can be determined according to different plants, provided that the required selenium-enriched product is applied before harvest. When the plant is tea, it is preferred to spray the chitosan functionalized nano-selenium fertilizer composition of the present invention 45-60 days before picking, spraying 3-5 times in total, with an interval of 6-10 days between two sprayings. The dilution multiple of the agent is 500-1000 times, and the amount of liquid sprayed each time is controlled to be 30-60 L / mu.

[0048] Beneficial effects:

[0049] The inventors have found through experiments that the tetrahydropyrimidine can significantly promote the absorption of chitosan functionalized nano-selenium by plants and promote the enrichment of selenium in plants.

[0050] In the present invention, the addition of alginic acid can further increase the promoting effect of ectoine on plant absorption and enrichment of nano-selenium. In other words, alginic acid and ectoine produce a synergistic effect in promoting plant absorption of selenium. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. The reagents used in the present invention, tetrahydropyrimidine (CAS No.: 96702-03-3), alginic acid (CAS No.: 9005-32-7) trisiloxane polyoxyethylene ether (CAS No.: 67674-67-3), etc. can be purchased from the market unless otherwise specified.

[0052] In the following embodiments of the present invention, the chitosan functionalized nano-selenium is prepared by the following method:

[0053] (1) Mix a 20 mmol / L sodium selenite solution and a 30 mmol / L potassium iodide solution in a ratio of 1:1 (v / v), add 30 (v / v) times the amount of water as the sodium selenite solution, and stir evenly;

[0054] (2) adding an equal volume of 60 mmol / L ascorbic acid solution to the sodium selenite solution and reacting for 30 minutes;

[0055] (3) After aging for 24 hours, a light red transparent colloidal solution was obtained;

[0056] (4) Centrifuge at 10,000 rpm for 30 min to remove the supernatant, wash twice with distilled water and twice with ethanol to remove unreacted impurities;

[0057] (5) The nano-selenium particles were redispersed into an equal amount of sol, and a chitosan solution (average molecular weight 30KD) with a concentration of 0.32 mg / mL and an equal volume of the sodium selenite solution was added to obtain chitosan-functionalized nano-selenium.

[0058] Example 1

[0059] The formula composition is: 20 g of chitosan functionalized nano-selenium, 16 g of tetrahydropyrimidine, 24 g of trisiloxane polyoxyethylene ether, and deionized water to make up to 1000 g.

[0060] The preparation method is as follows: weigh a formula amount of trisiloxane polyoxyethylene ether, add it to a formula amount of deionized water and mix evenly; then, add a formula amount of tetrahydropyrimidine and stir evenly; finally, add a formula amount of chitosan functionalized nano-selenium and stir evenly to obtain the product.

[0061] Example 2

[0062] The formula composition is: 15 g chitosan functionalized nano-selenium, 12 g tetrahydropyrimidine, 22 g alginate, 30 g trisiloxane polyoxyethylene ether, and deionized water to make up to 1000 g.

[0063] The preparation method is as follows: weigh a formulated amount of trisiloxane polyoxyethylene ether, add it to a formulated amount of deionized water and mix evenly; then, add a formulated amount of alginate and stir evenly; then, add a formulated amount of ectoine and stir evenly; finally, add a formulated amount of chitosan functionalized nano-selenium and stir evenly to obtain the product.

[0064] Example 3

[0065] The formula composition is: 20 g chitosan functionalized nano-selenium, 16 g tetrahydropyrimidine, 20 g alginate, 24 g trisiloxane polyoxyethylene ether, and deionized water to make up to 1000 g.

[0066] The preparation method is the same as Example 2.

[0067] Example 4

[0068] The formula composition is: 25 g chitosan functionalized nano-selenium, 20 g tetrahydropyrimidine, 26 g alginate, 40 g trisiloxane polyoxyethylene ether, and deionized water to make up to 1000 g.

[0069] The preparation method is the same as Example 2.

[0070] Example 5

[0071] The formula composition is: 30 g of chitosan functionalized nano-selenium, 24 g of tetrahydropyrimidine, 24 g of alginate, 32 g of trisiloxane polyoxyethylene ether, and deionized water to make up to 1000 g.

[0072] The preparation method is the same as Example 2.

[0073] Comparative Example 1

[0074] The formula composition is: 20 g of chitosan functionalized nano-selenium, 24 g of trisiloxane polyoxyethylene ether, and deionized water to make up to 1000 g.

[0075] The preparation method is as follows: weigh a formula amount of trisiloxane polyoxyethylene ether, add it into a formula amount of deionized water and mix evenly; then, add a formula amount of chitosan functionalized nano-selenium and stir evenly to obtain the product.

[0076] Comparative Example 2

[0077] The formula composition is: 20 g of chitosan functionalized nano-selenium, 20 g of alginate, 24 g of trisiloxane polyoxyethylene ether, and deionized water to make up to 1000 g.

[0078] The preparation method is as follows: weigh a formula amount of trisiloxane polyoxyethylene ether, add it to a formula amount of deionized water and mix evenly; then, add a formula amount of alginate and stir evenly; finally, add a formula amount of chitosan functionalized nano-selenium and stir evenly to obtain the product.

[0079] Field trials

[0080] Test location: Changsha Town, Meijiang District, Meizhou City, Guangdong Province;

[0081] Experimental varieties: green tea (spring tea);

[0082] Test agent: products of Examples 1-5; products of Comparative Examples 1-2;

[0083] Test method: Select normally grown green tea, start spraying the products of Examples 1-5 and Comparative Examples 1-2 45 days before picking, spray once every 10 days, and spray 3 times in total. The dilution multiple of each product is to control the content of chitosan functionalized nano-selenium in the dilution liquid to 30ppm, and the amount of each spray liquid is controlled to be 50 L / mu. In addition, spraying an equal amount of clean water is used as a blank control. After the tea leaves can be picked, pick an appropriate amount of tea leaves and prepare green tea according to the tea frying method. Then, refer to the method in GB5009.93-2017 "National Food Safety Standard-Determination of Selenium in Food" (hydride atomic fluorescence spectrometry) to determine the selenium content of each treatment. The test was repeated 3 times and the average value was taken. The results are shown in Table 1 below.

[0084] Table 1 Detection results of selenium content in tea leaves treated with different methods

[0085] deal with Spraying concentration of chitosan functionalized nano-selenium (ppm) Selenium content in tea (mg / kg) Example 1 30 0.84 Example 2 30 1.10 Example 3 30 1.21 Example 4 30 1.16 Example 5 30 1.08 Comparative Example 1 30 0.22 Comparative Example 2 30 0.24 CK / 0.04

[0086] The results showed that the selenium content in the tea leaves treated with comparative examples 1-2 was 0.22-0.24 mg / kg. The selenium content in the tea leaves treated with Example 1, which was added with ectoine, was 0.84 mg / kg, which was significantly higher than that in comparative examples 1-2 and the blank control. The selenium content in the tea leaves treated with Examples 2-5, which contained both ectoine and alginic acid, was 1.08-1.21 mg / kg, which was significantly higher than that in Example 1. Among them, the selenium content in the tea leaves treated with Example 3 was the highest, reaching 1.21 mg / kg.

[0087] The present invention has been described through specific embodiments. Those skilled in the art can refer to the contents of the present invention and make appropriate changes to achieve corresponding other purposes. The relevant changes do not deviate from the contents of the present invention. All similar replacements and modifications are obvious to those skilled in the art and are considered to be included in the scope of the present invention.

Claims

1. A chitosan functionalized nano-selenium fertilizer composition, characterized in that: The components of the composition and their weight percentages are: Chitosan functionalized nano-selenium, 0.5-4.0% Ectohydropyrimidine, 0.8-3.2% Alginic acid, 0-3.0% Surfactant, 0.5-5.0% Deionized water, balance; The chitosan functionalized nano-selenium preparation method comprises: (1) Mix a sodium selenite solution with a concentration of 10-30 mmol / L and a potassium iodide solution with a concentration of 20-40 mmol / L in a volume ratio of 1:1, add 20-40 times the volume of water of the sodium selenite solution, and stir evenly; (2) adding an equal volume of ascorbic acid solution with a concentration of 50-70 mmol / L to the sodium selenite solution and reacting for 20-40 minutes; (3) After aging for 24 hours, a light red transparent colloidal solution was obtained; (4) centrifuging at 8000-10000 rpm for 20-40 minutes to remove the supernatant, and washing with water and alcohol to remove unreacted impurities; (5) The nano-selenium particles were redispersed into an equal amount of sol, and a chitosan solution with a concentration of 0.32-0.64 mg / mL and an equal volume of sodium selenite solution was added to obtain a chitosan-functionalized nano-selenium complex.

2. The chitosan functionalized nano-selenium fertilizer composition according to claim 1, characterized in that The components and their weight percentages in the composition are: Chitosan functionalized nano-selenium, 1.5-3.0% Ectoin, 1.2-2.4% Alginic acid, 2.0-2.6% Surfactants, 2.4-4.0% Deionized water, balance.

3. The method for preparing the chitosan functionalized nano-selenium fertilizer composition according to claim 1 or 2, characterized in that: The steps include: (1) Weigh the formulated amount of surfactant and add it to the formulated amount of deionized water and mix well; (2) Then, add the formulated amount of alginate and stir evenly; (3) Then, add the formulated amount of ectoine and stir evenly; (4) Finally, add the formulated amount of chitosan functionalized nano-selenium and stir evenly to obtain the product.

4. A method for increasing the selenium content in plants, characterized in that: The method comprises applying the chitosan functionalized nano-selenium fertilizer composition according to any one of claims 1 to 2, or the chitosan functionalized nano-selenium fertilizer composition prepared by the method according to claim 3 to plants, wherein the plants are tea leaves.

5. Use of the chitosan functionalized nano-selenium fertilizer composition according to any one of claims 1 to 2 or the chitosan functionalized nano-selenium fertilizer composition prepared by the method according to claim 3 in increasing the absorption and / or enrichment of selenium in tea.

6. Use of ectoine or a combination of ectoine and alginic acid for increasing the absorption and / or enrichment of selenium in plants, characterized in that: The method comprises applying ectoine or a combination of ectoine and alginic acid and chitosan functionalized nano-selenium to plants; The plant is tea; The chitosan functionalized nano-selenium preparation method comprises: (1) Mix a sodium selenite solution with a concentration of 10-30 mmol / L and a potassium iodide solution with a concentration of 20-40 mmol / L in a volume ratio of 1:1, add 20-40 times the volume of water of the sodium selenite solution, and stir evenly; (2) adding an equal volume of ascorbic acid solution with a concentration of 50-70 mmol / L to the sodium selenite solution and reacting for 20-40 minutes; (3) After aging for 24 hours, a light red transparent colloidal solution was obtained; (4) centrifuging at 8000-10000 rpm for 20-40 min to remove the supernatant, and washing with water and alcohol to remove unreacted impurities; (5) The nano-selenium particles were redispersed into an equal amount of sol, and a chitosan solution with a concentration of 0.32-0.64 mg / mL and an equal volume of sodium selenite solution was added to obtain a chitosan-functionalized nano-selenium complex.