A preparation method and application of nano-selenium

Abstract

The invention relates to the technical field of pepper phytophthora control, and relates to a preparation method and application of nano-selenium. The preparation method of the nano-selenium comprises the following steps: weighing 2-4 g of sodium selenite, dissolving it in 100-500 ml of deionized water, stirring for 1-2 hours to obtain a sodium selenite solution, adding 100-500 ml of 10-100 mM ascorbic acid solution, stirring for 24-48 hours, after the reaction is completed, centrifuging to remove the supernatant, washing to remove unreacted impurities, and freeze-drying to obtain nano-selenium. The nano-selenium can be used to prevent and control pepper blight.

Description

Technical Field

[0001] The invention relates to the technical field of pepper phytophthora control, and relates to a preparation method and application of nano-selenium. Background Art

[0002] Pepper blight can occur from the seedling stage to the mature plant stage, and usually starts from the base of the stem, so it is also called pepper black stem disease. This disease is a devastating soil-borne disease caused by pepper phytophthora ( Phytophthora capsici ) infects the phloem of peppers and causes the peppers to die. The huge harm caused to peppers is mainly because the pathogen can infect pepper seedlings, adult stems, fruits and leaves, which can cause a variety of symptoms, such as leaf wilting, fruit rot, stem necrosis and other symptoms. Even when the environmental conditions are suitable, the disaster can break out in a short period of time, causing pepper production reduction or even total crop failure, causing irreparable economic losses to pepper production.

[0003] Selenium is an essential trace element for the human body. It can improve human immunity, prevent cardiovascular diseases, and delay aging. Therefore, selenium supplementation is essential for the human body. In recent years, studies have found that nano-selenium has higher absorption and utilization rate, higher biological activity, and lower toxicity than conventional forms of selenium. The reason may be the unique high specific surface area and small size effect of nanomaterials. The use of nanotechnology to inhibit crop diseases has attracted widespread attention in the agricultural field. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a preparation method and application of nano-selenium.

[0005] The technical solution of the present invention is achieved in this way:

[0006] The invention provides a method for preparing nano-selenium, comprising the following steps: weighing 2-4 g of sodium selenite, dissolving it in 100-500 ml of deionized water, and stirring for 1-2 hours to obtain a sodium selenite solution, adding 100-500 ml of a 10-100 mM ascorbic acid solution, and stirring for 24-48 hours; after the reaction is completed, centrifuging to remove the supernatant, washing to remove unreacted impurities, and freeze-drying to obtain the nano-selenium.

[0007] The invention also provides application of the nano-selenium in preventing and treating pepper blight.

[0008] Preferably, the nano-selenium induces the death of Phytophthora capsici hyphae.

[0009] The invention also provides a fungicide for preventing and treating pepper blight, wherein the active ingredient of the fungicide includes nano-selenium.

[0010] The invention also provides application of the nano-selenium in promoting the growth of pepper plants.

[0011] Beneficial technical effects of the present invention:

[0012] (1) The present invention proposes the application of nano-selenium in the prevention and treatment of pepper blight. Nano-selenium has the function of inducing the death of pepper blight mycelium. It is expected to be used to prepare a new fungicide against pepper blight, reduce pesticide resistance, and improve the prevention and treatment effect of pepper blight.

[0013] (2) The nano-selenium nanomaterials provided by the present invention can not only effectively prevent and control the infection of pepper phytophthora to plants, but also meet the needs of crops for selenium during growth and development, thereby increasing crop yields, while promoting plants to absorb selenium and improving crop quality.

[0014] (3) The nano-selenium material synthesized by the present invention has excellent antibacterial activity against Phytophthora capsici. 50 The storage stability test showed that the product has obvious antibacterial activity under low temperature (4°C) and room temperature (35°C) storage conditions (100 days), and the antibacterial effect is relatively stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the experimental picture of nano-selenium inhibiting pepper phytophthora;

[0016] Figure 2 This is an experimental diagram showing the effect of nano-selenium on pepper phytophthora under different storage conditions;

[0017] Figure 3 This is the graph showing the change in storage stability of nano-selenium;

[0018] Figure 4 This is the phenotype diagram of the in vivo experiment of nano-selenium to control Phytophthora capsici in pepper plants;

[0019] Figure 5 This is an experimental diagram of the effect of nano-selenium on the growth of pepper plants. DETAILED DESCRIPTION

[0020] In order to better understand the technical content of the present invention, specific embodiments are provided below to further illustrate the present invention.

[0021] Weigh 2 to 4 g of sodium selenite and dissolve it in 100 to 500 ml of deionized water and stir for 1 to 2 h to obtain a sodium selenite solution. Add 100 to 500 ml of 10 to 100 mM ascorbic acid solution and stir for 24 to 48 h. After the reaction is completed, a nano-selenium solution mother liquor is obtained.

[0022] Example 1 - Effect of Nano-Selenium on the Vegetative Growth of Phytophthora capsici

[0023] The mother solution of nano-selenium solution was placed in PDA medium and then inoculated with pepper phytophthora.

[0024] The specific operation is: use a 0.5mm diameter puncher to make a bacterial cake, inoculate it into the culture medium with nano-selenium, culture it in a constant temperature incubator at 28 degrees for 5 days, measure and record the diameter of the colony and take pictures. The results are shown in Figure 1 .

[0025] The mycelium growth inhibition rate was calculated according to the following formula:

[0026] Inhibition rate (%) = (colony diameter of control group - colony diameter of treatment group) / (colony diameter of control group - 0.5) * 100

[0027] The EC value of nano-selenium on pepper phytophthora was calculated by growth inhibition rate 50 It is 10-15 mg / L.

[0028] Example 2 - Effects of Nano-Selenium on Capsicum Phytophthora under Different Storage Conditions

[0029] The synthesized nano-selenium mother solution was stored under different conditions (4°C, 35°C) and the changes in the biological activity of nano-selenium were tested at different time points. The experimental results are shown in the following photos. Figure 2 shown. Figure 3 The graph shows the change of storage stability of nano-selenium. It can be seen from the graph that under low temperature conditions, at 4°C, the biological activity of nano-selenium has not changed significantly. 50 Maintained at around 15-20 mg / L, the biological activity of nano-selenium at 35°C changed greatly, with poor stability and decreased biological activity. Its biological activity EC against pepper phytophthora 50 It becomes about 25-30 mg / L. Nano-selenium is more conducive to maintaining its biological activity at low temperatures.

[0030] Example 3 - Effect of Nano-Selenium on the Growth of Pepper Plants

[0031] The pot method was used to determine the biological activity of nano-selenium against pepper phytophthora. The nano-selenium mother solution was diluted with ultrapure water to 1, 10, and 50 mg / L, and sprayed on the leaves of the plants once a week for three consecutive times. The CK group used ultrapure water as a control, and the biological pesticide berberine (Ber) and the chemical pesticide azoxystrobin (Azo) were used as controls. Pepper phytophthora was inoculated by root irrigation, and the changes of pepper plants after different treatments were observed.

[0032] from Figure 4 It can be seen that after the treatment with 50 mg / L of nano-selenium, the resistance of pepper plants to Phytophthora capsici was significantly improved. At the same time, nano-selenium promoted the growth of pepper plants. Compared with the chemical pesticide azoxystrobin and the biological pesticide berberine, nano-selenium has better biological activity. Figure 5It can be seen that the growth of pepper plants treated with 50 mg / L nano-selenium, including root weight, stem weight, plant height and leaf weight, increased by about 50% compared with the control group.

Claims

1. An application of nano-selenium in preventing and treating pepper blight, characterized in that: The preparation method of nano-selenium comprises the following steps: weighing 2-4 g of sodium selenite, dissolving it in 100-500 ml of deionized water, stirring for 1-2 hours to obtain a sodium selenite solution, adding 100-500 ml of 10-100 mM ascorbic acid solution, stirring for 24-48 hours, after the reaction is completed, centrifuging to remove the supernatant, washing to remove unreacted impurities, and freeze-drying to obtain nano-selenium; The nano-selenium induces the death of pepper phytophthora hyphae.

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