Method for improving the yield of selenium-rich rice by increasing tillering

Abstract

The present invention discloses a method for improving the yield of selenium-rich rice by increasing tillers, which belongs to the technical field of nano agriculture. The method of the present invention is to apply a spherical Se NMs solution to the leaf surface of rice seedlings, where the spherical Se NMs have a size of 10-90 nm, a hydration radius of 160-200 nm, a surface charge of -15--18 mV, and a purity of 95% or more. The rice seedling stage refers to the stage when rice reaches "one core and three leaves (three leaves have fully grown, but the fourth leaf has just emerged)", and the spherical Se NMs solution is an aqueous solution of spherical Se NMs with a concentration of 1-3 mg / L. The method of the present invention can significantly improve the rhizosphere microbial community of rice, increase root system secretions, change the soil environment, promote nutrient absorption by roots, significantly increase the Se content in rice, control the synthesis of gibberellin by rice, up-regulate the expression of tiller genes, significantly increase the number of tillers in the rice plant body, and increase the rice yield.

Description

Technical Field

[0001] The present invention relates to a method for improving the yield of selenium-rich rice by increasing tillers, and belongs to the technical field of nano-agriculture.

Background Art

[0002] Selenium (Se) is a constituent element of glutathione peroxidase in the human body and an important component for maintaining various enzyme activities. It has functions such as antioxidant, anti-cancer, and immune enhancement in the human body. Selenium supplementation from food is one of the main means to satisfy the selenium supply of the human body.

[0003] Selenium-rich rice is currently one of the main routes for the human body to intake selenium, and its economic value is also 1 to 5 times higher than that of ordinary rice. Currently, the main method for producing selenium-rich rice is to fertilize the soil with selenium fertilizers such as sodium selenate and sodium selenite. However, the utilization efficiency of these traditional selenium fertilizers is less than 20%, and a large amount of selenium fertilizers remain, causing serious soil environmental problems. Although there are those who apply zero-valent selenium as a selenium fertilizer, zero-valent selenium is an inert selenium ore with low hydrophilicity and low bioavailability. There are also those who apply nano-selenium as a selenium fertilizer, but nano-selenium has low purity and contains many other types of components (such as stabilizers and antibacterial agents) in the fertilizer, which has an unnecessary impact on plants and the soil environment.

[0004] Currently, research on selenium-rich rice mainly focuses on the selenium enrichment effect of rice. According to a research report, Se NMs, which are Se nano materials, can promote the formation of callus tissue organs and root growth of plants, increase the photosynthesis and yield of crops, and enhance the nutritional quality of crops (such as Se content, soluble sugar, soluble protein, antioxidant enzyme activity, etc.). However, these mechanism studies are targeted at dicotyledonous plants such as mung beans and tobacco. As a monocotyledonous plant, rice has extremely different traits. In terms of the growth environment, the difference between the two is significant. Different from the former, rice is a paddy crop and has a situation of dry-wet alternation throughout its life cycle. Regarding the yield of the latter compared to the former, the research focuses on the fruits at the mature stage. More importantly, the growth at the tillering stage is extremely important for rice, but plants such as mung beans and tobacco have no tillering requirement, so the tillering effect of rice cannot be directly expected from the growth effects of plants such as mung beans and tobacco.

[0005] In addition, increasing the application rate of agricultural chemical fertilizers and providing microbial fertilizers are generally used to increase the yield of rice. Among them, the application of chemical fertilizers can supply more effective nutrients to rice, promote the growth of rice, and increase the yield. The application of microbial fertilizers can supply more beneficial bacteria to the rhizosphere soil, reduce the incidence of diseases such as rice blast, and ensure the yield of rice. However, all of these existing methods have drawbacks. Excessive dependence on chemical fertilizers may lead to serious environmental pollution, deterioration of soil structure, and phenomena such as "fertilizer burn". On the other hand, excessive dependence on microbial fertilizers may cause significant changes in the microbial community in the soil and have an adverse impact on the growth of crops. Currently, there are relatively few studies on how to affect the traits at the tillering stage of rice to increase its yield, and the related control mechanisms at the tillering stage of rice are not yet clear.

[0006] In recent years, due to their high activity, Se nanomaterials (Se NMs) have been attracting attention and being recognized as Se fertilizers. However, there is no literature mentioning under what conditions Se NMs can stably and efficiently promote rice growth and increase Se content. Also, it does not mention how the application rate of Se NMs affects Se accumulation in crops. It is also not mentioned whether Se NMs can increase the yield of Se-rich rice by controlling the hormone level, gene expression and rhizosphere environment of rice, enhancing the availability of nutrient utilization, and promoting tillering and growth of rice.

Summary of the Invention

Problems to be Solved by the Invention

[0007] Currently, for the production of Se-rich rice, it is necessary to adopt sodium selenate and compound fertilizers. Their Se-enrichment effect is poor, likely to cause environmental pollution, and the effect of increasing yield is not obvious, and the tillering effect is not mentioned at all.

[0008] To solve at least one of the above problems, the present invention provides a method for improving the yield of Se-rich rice by increasing tillering, clarifies the important effects of factors such as the particle size, application rate, application time and application method of Se nano-fertilizer for producing Se-rich rice, and factors such as rhizosphere environment, important genes, hormone levels, etc., enhances the absorption efficiency of nutrients by the soil, increases the effective tillering number of rice, and achieves the purpose of increasing Se content. The present invention can significantly improve the structure of soil microbial communities and the generation of root exudates by applying synthetic Se nano-fertilizer to the leaf surface during the rice seedling stage, promote nutrient absorption, promote effective tillering of rice, increase the yield, and promote the enrichment of Se in rice.

Means for Solving the Problems

[0009] The first object of the present invention is to provide a method for improving the yield of selenium-rich rice by increasing tillers by applying a spherical Se NMs solution to the leaf surface during the rice seedling stage.

[0010] In some embodiments of the present invention, the spherical Se NMs have a size of 10-90 nm, more preferably 40-60 nm, a hydration radius of 160-200 nm, a surface charge of -15 to -18 mV, and a purity of 95% or more.

[0011] In some embodiments of the present invention, the spherical Se NMs solution is an aqueous solution of spherical Se NMs with a concentration of 1-3 mg / L.

[0012] In some embodiments of the present invention, the application amount of the spherical Se NMs solution is 0.5-2 mL / strain.

[0013] In some embodiments of the present invention, the spherical Se NMs solution is specifically applied in 1-5 times at intervals of 5-7 days starting from the time when the rice reaches the stage of "one core and three leaves".

[0014] In some embodiments of the present invention, the rice seedling stage is the time when the rice reaches the stage of "one core and three leaves".

[0015] In some embodiments of the present invention, the preparation method of the spherical Se NMs is described in Patent CN112010271A, specifically, Step (1) of mixing a selenium source and a reducing agent, fully pulverizing them into a red paste, and then stopping the pulverization; Step (2) of adding water to the red paste obtained by pulverization in step (1) and dispersing it; Step (3) of putting the solution obtained in step (2) into a container, dropping a surface modifier thereto, performing ultrasonic treatment, after completion of the treatment, centrifuging, freeze-drying the obtained supernatant and precipitate respectively, and finally obtaining spherical Se NMs. The selenium source in step (1) is any one or a combination of one or more of selenium dioxide, sodium selenite, selenous acid, and sodium selenate. The reducing agent is any one or a combination of one or more of ascorbic acid, citric acid, sucrose, and fructose. The molar ratio of the selenium source to the reducing agent is 1:2. The surface modifier in step (3) is any one of polyvinylpyrrolidone, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, dextran, and chitosan. The addition amount of the surface modifier accounts for 5-25% of the total mass of the Se source and the reducing agent, and the addition amount of the surface modifier accounts for 10%-15% of the total mass of the Se source and the reducing agent. The ultrasonic treatment is at a temperature of 18-25 °C, a power of 100-500 W, and a time of 30-120 min.

[0016] In some embodiments of the present invention, the method is to apply the spherical Se NMs solution to the leaf surface during the rice seedling stage. The rice seedling stage is the time when the rice reaches "one core and three leaves". The spherical Se NMs have a size of 40-90 nm, a hydration radius of 160-200 nm, a surface charge of -15 to -18 mV, and a purity of 95% or more. The spherical Se NMs solution is an aqueous solution of spherical Se NMs with a concentration of 1-2 mg / L. The application amount of the spherical Se NMs solution is 1-2 mL / strain. Specifically, the spherical Se NMs solution is applied in 1-5 times at intervals of 5-7 days starting from the time when the rice reaches "one core and three leaves".

[0017] The preparation method of the spherical Se NMs is Step (1) of mixing the selenium source and the reducing agent and grinding them sufficiently to form a red paste, and then stopping the grinding. Step (2) of adding water to the red paste obtained by grinding in step (1) and dispersing it. Put the solution obtained in step (2) into a container, dropwise add a surface modifier thereto, perform ultrasonic treatment, after completion of the treatment, centrifuge, and freeze-dry the obtained supernatant and precipitate respectively, and finally, step (3) of obtaining spherical Se NMs, and the selenium source in step (1) is any one or a combination of more than one of selenium dioxide, sodium selenite, selenous acid, and sodium selenate, the reducing agent is any one or a combination of more than one of ascorbic acid, citric acid, sucrose, and fructose, and the surface modifier in step (3) is any one of polyvinylpyrrolidone, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, dextran, and chitosan. The second object of the present invention is the use of the method of the present invention in the agricultural field.

[0018] The third object of the present invention is a method for improving the selenium content in rice by applying a spherical Se NMs solution to the leaf surface during the rice seedling stage. The spherical Se NMs have a size of 10 to 90 nm, the rice seedling stage is the time when the rice reaches "one core and three leaves", the spherical Se NMs solution is an aqueous solution of spherical Se NMs with a concentration of 1 to 3 mg / L, the application amount of the spherical Se NMs solution is 0.5 to 2 mL / strain, and the spherical Se NMs solution is specifically applied in 1 to 5 times at intervals of 5 to 7 days starting from the time when the rice reaches "one core and three leaves". A method is provided.

Effects of the Invention

[0019] The beneficial effects of the present invention are as follows.

[0020] (1) The mechanism of increasing tillers and promoting selenium enrichment of the present invention is as follows: Se NMs increase the content of root exudates in the rhizosphere environment, improve the soil environment, can gather more beneficial microorganisms using root exudates as a carbon source, promote the growth of rice roots, enhance the effectiveness of soil nutrients, can enhance the selenium enrichment efficiency of rice, control the gibberellin level and the expression of tillering genes in rice, and can increase the number of tillers of rice.

[0021] (2) The method of the present invention can significantly improve the rhizosphere environmental community of rice, increase the secretion from the roots, change the soil environment, promote the absorption of nutrients (N) from the roots, significantly increase the Se content in rice, and can increase it by more than 1.5 times compared to the plants without adding selenium fertilizer. It can control the synthesis of gibberellin by rice and up-regulate the expression of the tillering gene, significantly increase the number of tillers of the rice plant, and can increase it by more than 1.5 times compared to the plants without adding selenium fertilizer, increase its yield, and can increase it by more than 1.4 times compared to the plants without adding selenium fertilizer.

[0022] (3) The Se nanomaterial (Se NMs) used in the present invention has advantages such as high purity, high hydrophilicity, high bioavailability, and no other impurities compared with conventional zero-valent selenium and nano-selenium fertilizers.

Brief Description of the Drawings

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Best Mode for Carrying Out the Invention

[0024] Hereinafter, preferred embodiments of the present invention will be described. It should be understood that the embodiments are for better explaining the present invention and are not for limiting the present invention.

[0025] Test method: 1. Measurement of the contents of Se and nitrogen Se content: After pulverizing the rice grain samples of completely dried rice, they were uniformly mixed and sieved (60 mesh), a certain mass of the sample was weighed into a digestion tube, nitric acid was added, the digestion tube was sealed, and then placed in a microwave digester for digestion. After the digestion was completed, the sample was filtered and tested using an inductively coupled plasma mass spectrometer.

[0026] Nitrogen content: After pulverizing the root samples of completely dried rice, they were uniformly mixed and sieved (60 mesh), a certain mass of the sample was weighed and wrapped in a tin boat, and measured using an elemental analyzer.

[0027] 2. Measurement of rhizosphere microorganisms The collected fresh soil samples were immediately frozen with liquid nitrogen. After taking 2 g of the soil and uniformly pulverizing it, it was put into a centrifuge tube, and the microorganisms in the soil were measured using the 16S rRNA gene standard method.

[0028] 3. Measurement of root exudates The freshly collected soil samples were immediately frozen with liquid nitrogen. 1 g of the soil sample was taken, ground uniformly in liquid nitrogen, then placed in a 2 ml centrifuge tube. 1.5 ml of the extraction solution (80% methanol aqueous solution containing 0.1% formic acid and internal standard substance) was added, and it was placed in a refrigerator at 4 °C for pre-cooling and preservation, and vortexed uniformly. Ultrasonic treatment was performed for 30 min (35 kHz) in an ice bath. Then, centrifugation was carried out at 4 °C and 12,000 rpm for 15 min, and the supernatant was vacuum rotary dried with a rotary evaporation concentrator (connected to a cold trap), redissolved with 200 μL of methanol acetonitrile water (4:4:2), centrifuged at 4 °C and 12,000 rpm for 10 min to obtain the supernatant. The supernatant was temporarily stored at 4 °C. Then, the processed sample was tested with the instrument, and if it was to be stored for a long time, it needed to be placed at -20 °C.

[0029] Instrument model number: Thermo Scientific UPLC Vanquish. TIFF0007690062000001.tif76170 Mobile phase: Aqueous phase A: 0.1% formic acid aqueous solution Organic phase B: 0.1% formic acid acetonitrile solution Mobile phase flow rate: 0.35 ml / min Injection volume: 5 μL Column temperature: 35 °C Column type: ACQUITY UPLC HSS T3 (2.1×100 mm, 1.8 μm).

[0030] 4. Measurement of rice hormones Endogenous hormones were extracted from liquid rice using an isopropyl alcohol / water / hydrochloric acid solution, and extraction with dichloromethane and sample concentration by nitrogen purge were performed, and measurement was carried out using liquid phase-mass spectrometry (ESI-HPLC-MS / MS).

[0031] 5. Measurement of rice tillering genes Important genes of tillering were measured by DNA polymerase chain reaction. First, total RNA was extracted using an RNA extraction kit, and then a DNA template was obtained using a reverse transcription kit. Finally, the DNA template, fluorescent probe, and tillering gene primers were mixed according to the kit's method, and the test was conducted using a DNA polymerase chain reaction apparatus.

[0032] 6. Test of tillering number Rice generally starts tillering about 1 month after transplanting and lasts for about 1 month. On the 60th day after transplanting, the tillering number value of rice was measured. Five sampling points were set in the paddy field using the "Z"-shaped sampling method. Ten data were selected from each sampling point, for a total of 50 data, and the average value was taken.

[0033] 7. Test of yield Generally, the weight of rice grains per plant at the harvest stage is taken as the yield value of the rice of the present invention.

[0034] Example 1 The preparation method of spherical Se NMs includes the following steps.

[0035] (1) Weigh 0.11 g of selenium dioxide and 0.36 g of ascorbic acid so that the molar ratio of both is 1:2. Put them in a mortar, mix them, and then grind them thoroughly at 20 °C for 1 - 10 min to make a red paste.

[0036] (2) Add 20 mL of deionized water to the red paste obtained by grinding in step (1) and disperse it.

[0037] (3) Put the solution obtained in step (2) into a container, add 47 mg of polyvinylpyrrolidone (PVP) to it, perform ultrasonic treatment at 20 °C and 300 W for 60 min. After the treatment is completed, centrifuge at 4 °C and 10000 r / min, and lyophilize the obtained precipitate to finally obtain spherical Se NMs.

[0038] The results of the performance test on the obtained spherical Se NMs are shown in Table 1.

[0039] Table 1 Characterization of Spherical Se NMs TIFF0007690062000002.tif18170 Example 2 The method for improving the yield of selenium-rich rice by increasing tillering includes the following steps.

[0040] (1) Rice seeds from the Jiangsu Academy of Agricultural Sciences were cultivated in a seedling bed base.

[0041] (2) Rice seedlings at the "one core and two leaves" (The two leaves have fully grown, but the three leaves have just emerged stage were transplanted into a standard paddy field (cultivation density: 10,000 plants per mu) by mechanical transplanting.

[0042] (3) After cultivating for 10 days until the "one core and three leaves" stage, the spherical Se NMs aqueous solution of Example 1 at 1.5 mg / L was sprayed on the leaves, and after further cultivating for 140 days, the rice was harvested, and the spraying amount was 1 mL / plant.

[0043] Comparative Example 1 Except that the spherical Se NMs solution in Example 2 was into water changed, the rest was the same as in Example 2 to obtain rice.

[0044] The results of the performance tests on the rice in Example 2 and Comparative Example 1 are as follows.

[0045] Figure 2 is a comparison of the N content in the roots of the rice in Example 2 and Comparative Example 1. From Figure 2, it can be seen that the nitrogen content in the roots of the rice after Se NMs treatment increased by 10%, suggesting that the nutrient supply of the rice was improved and contributed to the growth of the rice.

[0046] Figure 3 is a comparison of the Se content in the rice in Example 2 and Comparative Example 1. From Figure 3, it can be seen that the selenium content in the rice grains after Se NMs treatment increased by 50%, suggesting that the selenium enrichment technology of the present invention is valuable and meets the standards of selenium-enriched agricultural products.

[0047] Figure 4 shows the comparison of the effective tiller numbers of rice in Example 2 and Comparative Example 1. From Figure 4, it can be seen that the tiller number of rice after Se NMs treatment increased by 50%, suggesting that the number of panicles at the maturity stage of rice theoretically increased by about 50%, which has a significant impact on the rice yield.

[0048] Figure 5 shows the comparison of the yields of rice in Example 2 and Comparative Example 1. From Figure 5, it can be seen that the yield of rice after Se NMs treatment increased by 40%, which is due to the increase in the tiller number.

[0049] Figure 6 shows the difference in the root-associated microorganisms of rice in Example 2 and Comparative Example 1. From Figure 6, it can be seen that the beneficial microorganisms in the rhizosphere soil increased due to Se NMs treatment. Among them, the relative abundance of Herbaspirillum sp. was 88.7%, the relative abundance of Desulfovibrio putealis was 29.2%, the relative abundance of Geobacter daltonii was 199.0%, and the relative abundance of Anaeromyxobacter sp. was 144.8% increased, which is beneficial to the growth of the rice root system and the improvement of the ability of rice to acquire soil nutrients.

[0050] Figure 7 shows the change in the root exudates of rice in Example 2 and Comparative Example 1. From Figure 7, it can be seen that in the rice after Se NMs treatment, the content of low-molecular-weight organic matter in the rhizosphere soil increased. Among them, the relative abundance of pyruvic acid was 58.9%, the relative abundance of L-phenylalanine was 607.4%, and the relative abundance of citric acid was 584.8% increased, which helps to regulate the acid-base balance in the soil, enhance the availability of soil nutrients, and promote the growth of rice.

[0051] Figure 8 shows the changes in gibberellin content in rice in Example 2 and Comparative Example 1, where A is the content of GA1 and B is the content of GA4. From Figure 8, in the rice after Se NMs treatment, changes in the gibberellin level were observed. When the gibberellin (GA1 and GA4) content increased during the tillering stage, the tiller number of rice decreased, and further the yield decreased. Se NMs decreased the gibberellin level in rice, which helps increase the tiller number of rice and improve the yield of rice.

[0052] Figure 9 shows the changes in the content of tillering genes in rice in Example 2 and Comparative Example 1. From Figure 9, it was found that in the rice after Se NMs treatment, the relative expression levels of the tillering genes (MOC1, TB1, OSH1) increased, suggesting that the tiller number of rice increased and the final yield increased.

[0053] Comparative Example 2 Rice was obtained in the same manner as in Example 2, except that the spherical Se NMs solution in Example 2 was changed to a sodium selenite solution with a selenium content of 1.5 mg / L.

[0054] Comparative Example 3 Rice was obtained in the same manner as in Example 2, except that the spherical Se NMs in Example 2 was changed to commercially available zero-valent selenium (purity 99%, 20 μm).

[0055] Comparative Example 4 Rice was obtained in the same manner as in Example 2, except that the spherical Se NMs in Example 2 was changed to commercially available flaky nanoselenium (purity 90%, length 200 nm, width 90 nm).

[0056] Comparative Example 5 Rice was obtained in the same manner as in Example 2, except that the spherical Se NMs in Example 2 was changed to commercially available wire-shaped nanoselenium (purity 90%, length 1 μm, diameter 20 nm).

[0057] Comparative Example 6 Except that the spherical Se NMs in Example 2 were changed to commercially available spherical Se NMs (purity 80%, diameter 80 nm), the rest was the same as in Example 2 to obtain rice.

[0058] The test results of the rice in Example 2 and Comparative Examples 1 to 6 are shown below.

[0059] Table 2 Test results of Example 2 and Comparative Examples 1 to 6 TIFF0007690062000003.tif82170 Example 3 Referring to the method for synthesizing spherical Se NMs described in Patent CN112010271A, the particle sizes of the spherical Se NMs in Example 1 were set to 10 nm, 40 nm, 100 nm, and 200 nm, and the rest was the same as in Example 2 to obtain rice.

[0060] The test results of the obtained rice are shown below.

[0061] Table 3 Test results of Example 3 TIFF0007690062000004.tif73170 Example 4 Except that the application amount of the spherical Se NMs solution in Example 2 was adjusted to 0.5, 1.5, and 2 mL / strain, the rest was the same as in Example 2 to obtain rice.

[0062] The test results of the obtained rice are shown below.

[0063] Table 4 Test results of Example 4 TIFF0007690062000005.tif57170 Example 5 Except that the spherical Se NMs solution in Example 2 was applied 1, 2, 3, and 5 times at 7-day intervals starting from the time when the rice reached the "one core and three leaves" stage, the rest was the same as in Example 2 to obtain rice.

[0064] Table 5 Test results of Example 5 TIFF0007690062000006.tif57170 Example 6 Rice plants were obtained in the same manner as in Example 2, except that the application concentrations of the spherical Se NMs solution in Example 2 were set to 1, 2, and 3 mg / L.

[0065] Table 6 Test results of Example 6 TIFF0007690062000007.tif57170Although the present invention has been disclosed in better embodiments as described above, it is not intended to limit the present invention. Those skilled in the art can make all changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be in accordance with that defined in the claims.

Claims

1. A method for improving the yield of selenium-rich rice by increasing tillering, wherein a spherical Se NMs solution is applied to the leaf surface when the rice reaches the "one shoot and three leaves" stage, The spherical Se NMs is obtained by a preparation method including step (1) of mixing a selenium source and a reducing agent, pulverizing them sufficiently to form a red paste, and then stopping the pulverization; step (2) of adding water to the red paste obtained by pulverization in step (1) and dispersing it; and step (3) of putting the solution obtained in step (2) into a container, dropping a surface modifier thereto, performing ultrasonic treatment, after completion of the treatment, centrifuging, freeze-drying the obtained supernatant and precipitate respectively, and finally obtaining spherical Se NMs. Se NMs is a Se nanomaterial characterized by the method.

2. The method according to claim 1, wherein the spherical Se NMs has a size of 10-90 nm, a hydration radius of 160-200 nm, a surface charge of -15 to -18 mV, and a purity of 95% or more.

3. The method according to claim 1, wherein the spherical Se NMs solution is an aqueous solution of spherical Se NMs with a concentration of 1-3 mg / L.

4. The method according to claim 1, wherein the application amount of the spherical Se NMs solution is 0.5-2 mL / strain.

5. The method according to claim 1, wherein the spherical Se NMs solution is specifically applied in 1-5 times at intervals of 5-7 days starting from the time when the rice reaches the "one shoot and three leaves" stage.

6. Use of the method according to any one of claims 1 to 5 in the agricultural field.

7. A method for improving the selenium content in rice, wherein a spherical Se NMs solution is applied to the leaf surface when the rice reaches the "one shoot and three leaves" stage, The spherical Se NMs is obtained by a preparation method including step (1) of mixing a selenium source and a reducing agent, pulverizing them sufficiently to form a red paste, and then stopping the pulverization; step (2) of adding water to the red paste obtained by pulverization in step (1) and dispersing it; and step (3) of putting the solution obtained in step (2) into a container, dropping a surface modifier thereto, performing ultrasonic treatment, after completion of the treatment, centrifuging, freeze-drying the obtained supernatant and precipitate respectively, and finally obtaining spherical Se NMs. Se NMs is a Se nanomaterial characterized by the method.

8. The spherical Se NMs have a size of 10 to 90 nm, the spherical Se NMs solution is an aqueous solution of spherical Se NMs with a concentration of 1 to 3 mg / L, the application amount of the spherical Se NMs solution is 0.5 to 2 mL / strain, and specifically, the spherical Se NMs solution is applied in 1 to 5 divided applications at intervals of 5 to 7 days starting from the time when the rice reaches the stage of "one shoot and three leaves". The method according to claim 7, characterized in that.

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