Selenium-rich millet and production method thereof

Abstract

The invention relates to selenium-rich millet and a production method thereof, and belongs to the field of agricultural production, in particular to spraying 22.5 g.hm <-2 > of nano-selenium on leaf surfaces of millet, so that agronomic characters of the millet can be remarkably improved, the nutritional quality of the millet can be improved, the selenium content in the millet can be increased, the selenium content is close to the selenium-rich content specified by the standard, and the selenium form is organic selenium.

Description

Technical Field

[0001] The invention relates to the technical field of agriculture, and relates to selenium-enriched millet and a production method thereof. Background Art

[0002] Millet has the advantages of short growth period, wide adaptability, drought resistance, barrenness resistance, and storage resistance. It has always been one of the traditional staple foods in China. Compared with wheat and rice, millet has a lower carbohydrate content, which is more conducive to the control of blood sugar in the human body. In addition, there is 5% dietary fiber in millet carbohydrates, and the content of high-quality dietary fiber is about 2.5 times that of rice. In addition to carbohydrates, millet is rich in nutrients such as protein, unsaturated fatty acids, vitamin B1, vitamin B2, iron, zinc, magnesium, etc., and has good edible and medicinal value.

[0003] Selenium (Se) is an essential micronutrient for the human body and is of great significance to human health. my country is a country with selenium deficiency, with about 51% of the regions lacking selenium. Studies have shown that Keshan disease and Kashin-Beck disease in humans are caused by selenium deficiency. In addition, selenium deficiency may lead to a variety of chronic diseases such as cardiovascular disease, diabetes, cancer, thyroid disease, inflammatory disease, viral infection and subfertility. Selenium cannot be directly absorbed by the human body and can only be supplemented through diet. Therefore, the use of a series of biofortification strategies to produce selenium-rich foods can help overcome selenium deficiency and improve human health. Cereals are the main contributors to human dietary selenium intake. The main forms of selenium in the diet can be divided into inorganic selenium and organic selenium. Inorganic selenium includes selenate and selenite, and organic selenium includes selenomethionine, selenocysteine ​​and selenomethylselenocysteine. Inorganic selenium is relatively toxic and it is difficult to control the dosage. If it is locally excessive in the human body, it will cause harm to the human body. Compared with inorganic selenium enhancers, biological organic selenium is safer, easily absorbed and utilized by the human body, and has a high efficiency of selenium supplementation.

[0004] Ways to enrich selenium in plants include soil application of selenium, foliar spraying of selenium, stem injection, seed soaking and seed dressing with selenium fertilizer, breeding of selenium-enriched varieties, etc. Among them, foliar spraying of selenium can directly transport selenium to the grains after being catalyzed by enzymes in the leaves, reduce the accumulation and retention in other organs of the plant, improve the utilization rate of selenium in the grains, and is easy to operate. It is the main method used in plant selenium-enriched production. In previous studies on plant selenium enrichment, exogenous selenium mainly included sodium selenite, sodium selenate and commercial compound selenium fertilizers (mainly composed of K2SeO4 and BaSeO4), etc., which are used in relatively high amounts and have potential environmental risks. At present, the production method of selenium-enriched millet is mainly to spray inorganic selenium solution on the millet leaves during the growth period of millet. After multiple sprayings, the selenium content in millet can reach the expected target. The first disadvantage is that the conversion rate of inorganic selenium is low and the residue is serious. Long-term consumption of millet obtained by this method has the risk of causing selenium poisoning in the human body; the second is that most organic selenium fertilizers on the market have low conversion rates, and the selenium content of the produced bio-fortified selenium-enriched foods is low.

[0005] Nano-selenium is a nano-sized particle of elemental selenium that has high biological activity, is safe and easily absorbed. Currently, there are relatively limited reports on the mechanism of the effect of foliar spraying of nano-selenium on the nutritional quality of millet and the total amount and form of selenium. Summary of the invention

[0006] In view of this, the main purpose of the present invention is to provide a selenium-enriched millet and a preparation method thereof.

[0007] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0008] The first aspect of the present invention is to provide a method for producing selenium-enriched millet, comprising the following steps:

[0009] (1) Preparation of selenium-enriched nutrient: using active nano-selenium-enriched technology to produce selenium-enriched nutrient;

[0010] (2) Spraying selenium-rich nutrients: Spraying selenium-rich nutrients during the heading stage or early grain filling stage of millet, with the spraying concentration of selenium-rich nutrients ranging from 250 ml of selenium-rich nutrients / 60 L of water / hectare to 500 ml of selenium-rich nutrients / 60 L of water / hectare;

[0011] (3) Field management: After spraying selenium fertilizer, there should be no rain within 24 hours. If there is a long-term drought, timely irrigation is required. The rest is carried out according to normal management;

[0012] (4) Harvesting: When all the grains turn yellow and harden, harvest them in time, dry them in the sun, thresh them and store them to obtain selenium-rich millet.

[0013] Furthermore, the selenium-rich nutrient is the Nongxike nano-selenium-rich nutrient produced by using active nano-selenium-enriched technology, with nano-selenium accounting for more than 98%, and the particle size of nano-selenium is 100-300 nanometers.

[0014] Furthermore, the spraying amount of the selenium-rich nutrient is 20-25 g·hm -2 Se; Preferably, the spraying amount of the selenium-rich nutrient is 22.5g·hm -2 Se.

[0015] Furthermore, the spraying step is to apply 1 / 2 of the total spraying amount at the heading stage and the filling stage respectively.

[0016] The second aspect of the present invention is to provide a selenium-rich millet, which is prepared by the method described in the first aspect of the present invention; preferably, the millet has increased β-carotene content and vitamin E content.

[0017] The third aspect of the present invention is to provide a method for increasing the beta-carotene content of millet and the yellowness value of yellow millet, wherein the method comprises spraying a certain amount of selenium-rich nutrient agent at the heading stage and the filling stage respectively, wherein the selenium-rich nutrient agent is an Nongxike nano-selenium-rich nutrient agent produced by using active nano-selenium-rich technology, wherein the nano-selenium accounts for more than 98%, and the particle size of the nano-selenium is 100-300 nanometers;

[0018] Furthermore, the spraying amount of the selenium-rich nutrient is 20-25 g·hm -2 Se.

[0019] The fourth aspect of the present invention is a method for increasing the vitamin E content of millet, wherein the method comprises spraying a certain amount of selenium-rich nutrient agent at the heading stage and the filling stage respectively, wherein the selenium-rich nutrient agent is an Nongxike nano-selenium-rich nutrient agent produced by using active nano-selenium-rich technology, wherein nano-selenium accounts for more than 98%, and the particle size of the nano-selenium is 100-300 nanometers;

[0020] Furthermore, the spraying amount of the selenium-rich nutrient is 20-25 g·hm -2 Se.

[0021] The beneficial effects of the present invention include:

[0022] 1) Foliar spraying significantly increased plant height, stem thickness, ear length, ear thickness, ear weight, and yield of millet; the optimal application rate of nano-selenium was 22.5 g·hm -2 ;

[0023] 2) In this experiment, selenium may increase photosynthesis by increasing β-carotene content, thereby increasing millet yield;

[0024] 3) Foliar spraying of nano-selenium fertilizer improved the arginine biosynthesis metabolic pathway, promoted the growth and development of millet, and thus increased the yield;

[0025] 4) In the experiment of the present invention, foliar spraying of nano-selenium increased the β-carotene content and yellowness value in millet. Foliar spraying of nano-selenium may increase the yellowness value of millet by increasing the β-carotene content in millet;

[0026] 5) In this experiment, foliar spraying of nano-selenium reduced the carbohydrate content in millet and increased the total dietary fiber content in millet; In this experiment, foliar spraying of nano-selenium increased the fat content in millet; In this experiment, foliar spraying of nano-selenium increased the vitamin E content in millet. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The effect of foliar spraying of nano-selenium on the total amount of selenium in millet;

[0028] Figure 2 Identification of metabolites in millet extracts: (a) PCA analysis results, (b) number of differential metabolites, (c) volcano plot;

[0029] Figure 3 Step by step for the top 50 differential metabolites;

[0030] Figure 4 The abundance changes of some differential metabolites are as follows: (a) arginine, (b) glutathione, (c) inulin, (d) galactosyl acid, (e) phosphatidylcholine (20:5(5Z,8Z,11Z,14Z,17Z) / 24:1(15Z)), (f) phosphatidylcholine (16:0 / 16:0), (g) phosphatidylcholine (16:0 / 22:5(4Z,7Z,10Z,13Z,16Z)), (h) phosphatidylcholine (14:0 / 2 2:4(7Z,10Z,13Z,16Z)), (i) phosphatidylcholine (14:0 / 20:2(11Z,14Z)), (j) glycerophosphocholine, (k) phosphatidylcholine (18:0 / 0:0), (l) phosphatidylcholine (15:0 / 0:0), (m) phosphatidylcholine (20:2(11Z,14Z) / 0:0), (n) phosphatidylcholine (22:4(7Z,10Z,13Z,16Z) / 0:0).

[0031] Figure 5 Functional enrichment analysis of differential metabolites: (a) KEGG enrichment map of differential metabolites, (b) metabolic pathway map of arginine biosynthesis. DETAILED DESCRIPTION

[0032] The following is a further description of the concept of the present invention and the technical effects produced in conjunction with specific embodiments, so as to fully understand the purpose, features and effects of the present invention. The methods are conventional methods unless otherwise specified. The materials can be obtained from public commercial channels unless otherwise specified. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0033] Example 1 Effect of spraying nano-selenium on millet growth and quality

[0034] 1.1 Test materials

[0035] Exogenous selenium donor: Nongxike nano-selenium-enriched nutrient. The selenium in the nutrient is prepared using active nano-selenium-enriched technology. Specification: 250ml / bottle. The total selenium content in each bottle is 22.5g, of which nano-selenium accounts for more than 98%, and the particle size of nano-selenium is 100-300 nanometers.

[0036] Millet variety tested: Jinmiao K5.

[0037] 1.2 Experimental design

[0038] The experiment was conducted in Shanzui Village, Xinzhen Town, Naiman Banner, Tongliao City, Inner Mongolia Autonomous Region from July to September 2023. The millet test field totaled 156 mu, which was divided into a control group and a group sprayed with different doses of nano-selenium. Four selenium concentrations were set in the experiment, namely T1: 22.5 g·hm -2 Se (11.25 g·hm2 was sprayed on the leaves at the heading stage and the filling stage respectively -2 Se), T2: 33.75 g·hm -2 Se (22.5 g·hm2 sprayed on leaves at heading stage -2 Se, 11.25 g hm-1 spray on leaves during the filling period -2 Se), T3: 45g·hm -2 Se (22.5 g·hm-1 sprayed on leaves at heading stage and filling stage -2 Se), and T0: clean water (spraying clean water on the leaves at the heading stage and the filling stage respectively), as shown in Table 1.

[0039] The test site is clay soil, containing 6.24 g·kg organic matter -1 , total nitrogen 1.83 mg kg -1 , hydrolyzable nitrogen 64 mg kg -1 , available phosphorus 3.3 mg kg -1 , fast-acting potassium 51.8 mg kg -1 , total selenium 0.09 mg kg -1 , pH 8.68, dry matter content 98.6%.

[0040] Table 1 Foliar spraying of selenium treatment

[0041]

[0042] 1.3 Measurement items and methods

[0043] 1.3.1 Determination of agronomic traits and yield

[0044] After the millet matured, 30 millet plants were randomly selected from each group to measure agronomic traits, including plant height, stem diameter, ear length, ear diameter, ear weight, and 1,000-grain weight; each group randomly selected 6 1m×1m areas excluding the side rows, and the total number of ears in the area was counted and converted into the number of ears per square meter for calculating yield. After the millet was harvested, it was naturally air-dried, threshed, and shelled to make millet, which was used to measure the following indicators.

[0045] 1.3.2 Determination of millet color

[0046] The color of millet was measured by a spectrophotometer, and the instrument was externally calibrated with a standard white tile. The three-color coordination system L*, a*, and b* was used to represent the color. About 50g of millet was poured into a quartz dish for measurement, and the L*, a*, and b* of the sample were measured by irradiating it with a standard light source. The L* value, a* value, and b* value represent brightness, red-greenness, and yellow-blueness, respectively. The larger the L* value, the brighter the beige, the larger the a* value, the redder the beige, and the larger the b* value, the yellower the beige.

[0047] 1.4 Data Analysis

[0048] The experimental data were analyzed using SPSS23.0 statistical software, and the comparison between the two groups was performed using independent t-test, and the comparison between multiple groups was performed using one-way analysis of variance. The results were expressed as "mean ± standard deviation", P < 0.05 was considered significant, and P > 0.05 was considered insignificant.

[0049] 1.5 Results

[0050] 1.5.1 Foliar spraying of different concentrations of nano-selenium can increase plant height, stem thickness, ear length, ear thickness, ear weight and yield of millet.

[0051] As shown in Table 2, foliar spraying of 22.5 g·hm -2 When nano-selenium was applied (T1), the plant height, stem diameter, ear length, ear diameter, ear weight, and yield of millet all reached the maximum value (P<0.05), increasing by 7.9%, 15.4%, 14.5%, 18.8%, 13.5%, and 9.8% respectively compared with the control group (T0). When nano-selenium was sprayed on the leaves at different concentrations, the plant height and stem diameter showed a trend of first decreasing and then increasing, and the increase in ear length, ear diameter, ear weight, and yield showed a trend of gradually decreasing with the increase of selenium concentration.

[0052] Table 2 Effects of foliar spraying of nano-selenium on agronomic traits of millet

[0053]

[0054] Note: Different letters in the same column represent significant differences (P<0.05), and the rest are the same.

[0055] 1.5.2 Effect of foliar spraying of nano-selenium on millet color

[0056] As shown in Table 3, the L* value of millet ranged from 66.72 to 67.28. The L* value of millet tended to increase with the increase of the concentration of nano-selenium sprayed on the leaves, but there was no significant difference between the groups (P>0.05). The a* value of millet ranged from 8.57 to 9.08. When 22.5 g·hm-1 was sprayed on the leaves, the L* value of millet increased. -2 When nano-selenium was applied to the leaves, the a* value of millet reached the maximum value, which was significantly higher than that of the control group (T0) and T2 group (P<0.05), but there was no significant difference with the T3 group (P>0.05). The b* value of millet varied between 29.85 and 31.51. Compared with the control group (T0), foliar spraying of different concentrations of nano-selenium significantly increased the b* value of millet (P<0.05), but there was no significant difference between the groups (P>0.05).

[0057] Table 3 Effects of foliar spraying of nano-selenium on L*, a*, and b* of millet

[0058]

[0059] Example 2 Effect of spraying nano-selenium on the nutritional components of millet

[0060] 2.1-2.2 Experimental materials and experimental design and 2.4 Data statistics are the same as in Example 1

[0061] 2.3 Determination of nutritional components

[0062] The moisture, protein, fat and total dietary fiber contents of millet were determined in accordance with GB 5009.3-2016 "National Food Safety Standard - Determination of Moisture in Food", GB 5009.5-2016 "National Food Safety Standard - Determination of Protein in Food", GB 5009.6-2016 "National Food Safety Standard - Determination of Fat in Food" and GB 5009.88-2014 "National Food Safety Standard - Determination of Dietary Fiber in Food", and carbohydrates (%) = 100-(protein + fat + moisture + total dietary fiber). The amylose content of millet was determined in accordance with GB / T15683-2008 “Determination of Amylose Content of Rice”, the vitamin E content of millet was determined in accordance with GB 5009.82-2016 “National Food Safety Standard Determination of Vitamins A, D and E in Foods”, the β-carotene content of millet was determined in accordance with GB 5009.83-2016 “National Food Safety Standard Determination of Carotene in Foods”, and the vitamin B1 content of millet was determined in accordance with GB 5009.84-2016 “National Food Safety Standard Determination of Vitamin B1 in Foods”.

[0063] 2.5 Results

[0064] As shown in Table 4, the main nutrients of millet are carbohydrates, with a content of more than 70%. It also contains protein, fat, dietary fiber and vitamins. Compared with the control group (T0), foliar spraying of nano-selenium had no significant effect on the moisture and protein content of millet (P>0.05). Compared with the control group (T0), foliar spraying of nano-selenium can increase the fat, total dietary fiber, amylose, vitamin E and β-carotene content of millet (P<0.05), among which the fat content increased by 8.33%, the total dietary fiber content increased by 19.56%, the amylose content increased by 2 times, the vitamin E content increased by 36% and the β-carotene content increased by 13.36%. Compared with the control group (T0), foliar spraying of exogenous selenium can reduce the carbohydrate and vitamin B1 content of millet (P<0.05), the carbohydrate content decreased by 1.70%, and the vitamin B1 content decreased by 7.14%.

[0065] Table 4 Effects of foliar spraying of nano-selenium on the nutritional components of millet

[0066]

[0067] Example 3 Effect of spraying nano-selenium on selenium content and morphology in millet

[0068] 3.1-3.2 Experimental materials and experimental design and 3.4 Data statistics are the same as in Example 1.

[0069] 3.3 Determination of total selenium content

[0070] The determination of selenium is carried out according to the national standard GB / T 5009.93-2017 "National Food Safety Standard Determination of Selenium in Food" by hydride atomic fluorescence spectrometry.

[0071] 3.5 Determination of selenium forms

[0072] Selenium forms are determined according to GHT 1429-2023 "Determination of five forms of selenium in agricultural products by high performance liquid chromatography-inductively coupled plasma mass spectrometry". The selenium form determination indicators include organic selenium (SeMet, SeCys2 and SeMeCys), inorganic selenium (SeO3 2- 、SeO4 2- ), soluble unknown selenium form (selenium element or selenium-containing compounds soluble in water), insoluble unknown selenium form (selenium element or selenium-containing compounds insoluble in water).

[0073] 3.6 Results

[0074] Depend on Figure 1 It can be seen that compared with the control group (T0), different concentrations of nano-selenium treatment significantly increased the total selenium content in millet (P<0.05), and the total selenium content of millet increased with the increase of foliar spraying nano-selenium concentration. The total selenium content of millet in the T3 treatment group reached the maximum value (1.57 mg / kg), which was 21.4 times higher than that in the control group (T0); there was no significant difference in the total selenium content of millet between the T1 group (1.04 mg / kg) and the T2 group (1.13 mg / kg) (P>0.05), but both were significantly higher than the control group (T0) (P<0.05), and increased by 13.9 and 15.1 times respectively compared with the control group (T0). Compared with the T1 and T2 groups, the total selenium content of millet in the T3 group was significantly increased (P<0.05); but only the selenium content in the millet in the T1 group was close to the requirements of "T / CATEA 003-2022: Selenium Content Standard for Selenium-rich Agricultural Products" (the total selenium content in grain crops and their primary processed products in the selenium-rich agricultural products category should be in the range of 0.15-1.00 mg / kg), so only the selenium form in the millet in the T1 group was tested. The results showed that the selenium detected in the millet in the T1 group was all organic selenium, namely selenocystine (SeCys2) and selenomethionine (SeMet), of which selenomethionine accounted for 96.80% of the total selenium.

[0075] Example 4 Effect of Spraying Nano-Selenium on Millet Metabolites

[0076] 4.1-4.2 Experimental materials and experimental design and 4.4 Data statistics are the same as in Example 1.

[0077] 4.3 Determination of metabolites in millet extract

[0078] Six replicates of millet powder were selected for metabolomics determination in the T0 and T1 treatment groups, respectively. The specific operation was as follows: 60 mg of millet sample was weighed, 20 μL of internal standard (L-2-chlorophenylalanine, 0.3 mg / mL, methanol preparation) and 1 mL of methanol: water (v:v = 7:3) were added; precooled in a -20 °C refrigerator for 20 min, ground in a grinder (60 Hz, 2 min); ultrasonic extraction in an ice-water bath for 30 min; standing at -20 °C for 20 min; low-temperature centrifugation for 15 min (13000 rpm, 4 °C), 200 μL of supernatant was drawn with a syringe, filtered with a 0.22 μm organic phase pinhole filter, transferred to an LC injection vial, and stored at -80 °C until LC-MS analysis.

[0079] The specifications of the chromatographic column were 1.7 μm, 2.1 mm × 100 mm (ACQUITY UPLC BEH C18); the mobile phase was divided into phase A and phase B, phase A was 0.1% formic acid solution, and phase B was 0.1% formic acid acetonitrile solution; the following gradient was used for separation: 0 min, 5% B; 2 min, 5% B; 4 min, 30% B; 8 min, 50% B; 10 min, 80% B; 14 min, 100% B; 15 min, 100% B; 15.1 min, 5% and 16 min, 5% B. The flow rate of the eluent was 0.4 mL / min, the column temperature was 40 ° C, and the injection volume was 5 μL. The temperature of the electrospray ion source (ESI) was 550 ° C, the voltage was 5500 V, and the curtain gas (CUR) was 35 psi.

[0080] 4.5 Results

[0081] 4.5.1 Identification of metabolites in millet extract

[0082] By performing principal component analysis on the samples, we can preliminarily understand the overall metabolite differences between the millet samples in the control group (T0) and the millet samples in the selenium-enriched group (T1) and the degree of variation between the samples in the groups. The separation trend of the metabolome between the two groups in the PCA results indicates whether there are differences in the metabolome within the sample groups. PCA score results ( Figure 2 In (a), the three biological replicates of each sample group were distributed more concentratedly, and the two groups of samples were clearly divided into two subgroups, indicating that the reproducibility within the sample group was good. A total of 4107 metabolites were detected in this project, with P-value < 0.05 and VIP > 1 as the difference screening criteria. Figure 2As shown in (b), there are a total of 213 differential metabolites, including 2 alkaloids and their derivatives, 8 benzene compounds, 93 lipids and lipidoids, 5 nucleoside and nucleotide analogs, 32 organic acids and their derivatives, 6 organic nitrogen metabolites, 17 organic oxygen metabolites, 25 organic heterocyclic metabolites, 11 phenylpropane and polyketide compounds, and 13 others. Among them, the number of differential metabolites with up-regulated expression is 111, and the number of differential metabolites with down-regulated expression is 102. Volcano plot ( Figure 2 Middle (c) shows that the screened metabolites can be clearly distinguished into two groups, indicating that the screened differential metabolites have high reliability.

[0083] 4.5.2 Screening and identification of differential metabolites

[0084] Cluster heat map analysis was performed on the top 50 differential metabolites of millet in the control group (T0) and millet in the selenium-enriched group (T1). The results are as follows Figure 3 As shown (gradient colors indicate the size of the quantitative value, the redder the color, the higher the expression level of the metabolite, and the bluer the color, the lower the expression level of the metabolite): inulin, 2-amino-3-methyl-1-butanol, lactulose, eptastine, N-docosahexaenoylglycine, N1,N10-dicoumaryl dispermine, phosphatidylcholine (18:2(2E,4E) / 16:0), phosphatidylethanolamine (18:0 / 18:2(9Z,12Z)), trioxophanone, cyanine, glutathione, apraclarithromycin B, N-(γ-glutamyl)ethanolamine, etc. were expressed at lower levels in the control group millet (T0), and at higher levels in the selenium-enriched group millet (T1); benzoyl-L-arginine methyl ester, phosphatidylethanolamine (O- The expression levels of 20:0 / 17:2(9Z,12Z)), galactonic acid, phospholipids (18:1(11Z) / 18:2(9Z,12Z)), ginger lipid A, ginger lipid B, 2-linoleylglycerol, phosphatidylcholine (15:1(9Z) / 19:0), phosphatidylcholine (18:0 / 18:1(13Z)), phosphoethanolamine (22:4(72,10Z,13Z,16Z) / 19:0), commensin B, phosphoglycerol (18:3(6Z,9Z,12Z) / 0:0), phosphoglycerol (18:2(9z,12Z) / 0:0), and dioscin were higher in the control group millet (T0), and lower in the selenium-enriched group millet (T1). The abundance changes of some differential metabolites are as follows: Figure 4, respectively: (a) arginine, (b) glutathione, (c) inulin, (d) galactosic acid, (e) phosphatidylcholine (20:5 (5Z, 8Z, 11Z, 14Z, 17Z) / 24:1 (15Z)), (f) phosphatidylcholine (16:0 / 16:0), (g) phosphatidylcholine (16:0 / 22:5 (4Z, 7Z, 10Z, 13Z, 16Z)), (h) phosphatidylcholine (14:0 / 22:4 ( 7Z,10Z,13Z,16Z)), (i) phosphatidylcholine (14:0 / 20:2(11Z,14Z)), (j) glycerophosphocholine, (k) phosphatidylcholine (18:0 / 0:0), (l) phosphatidylcholine (15:0 / 0:0), (m) phosphatidylcholine (20:2(11Z,14Z) / 0:0), (n) phosphatidylcholine (22:4(7Z,10Z,13Z,16Z) / 0:0).

[0085] 4.5.3 Functional enrichment analysis of differential metabolites

[0086] In order to further explore the metabolic pathways involved in the differential metabolites, KEGG enrichment analysis was performed on 213 differential metabolites. Using P < 0.05 as the threshold, the 20 pathways with the most significant enrichment of differential metabolites were screened out ( Figure 5 (a)), including N-glycosyl biosynthesis, glycerophospholipid metabolism, zeckadenine biosynthesis, arginine biosynthesis, histidine metabolism, ether lipid metabolism, linoleic acid metabolism, pantothenic acid and coenzyme A biosynthesis, β-alanine metabolism, cysteine ​​and methionine metabolism, starch and sucrose metabolism, glutathione metabolism, monolactam biosynthesis, α-linolenic acid metabolism, galactose metabolism, ABC transporters, aminoacyl-tRNA biosynthesis, folate biosynthesis, pyrimidine metabolism, arginine and proline metabolism. The arginine biosynthesis pathway mainly includes the urea cycle, the citric acid cycle and the arginine and proline metabolic pathway ( Figure 5 (b)).

[0087] Comparative Example 1

[0088] A millet planting area of ​​20 mu was selected in Shanzui Village, Xinzhen Town, Naiman Banner, Inner Mongolia. In the early morning of autumn, a drone was used to spray selenium-rich nutrients at one time at the beginning of millet filling. The spraying concentration of selenium-rich nutrients was 250ml selenium-rich nutrients / 60L water / hectare. The drone was sprayed 1.9 meters above the top of the millet. On the day of spraying selenium-rich nutrients, it should be ensured that there was no rain for 24 hours. After spraying selenium-rich fertilizers, timely irrigation is required in case of long-term drought, and the rest of the field management is carried out according to normal management. After the millet is harvested, the selenium content in the millet is sampled and tested. After testing, the average selenium content in millet is 2180μg / kg.

[0089] Comparative Example 2:

[0090] A millet planting site in Shanzui Village, Xinzhen Town, Naiman Banner, Inner Mongolia was selected, with a millet planting area of ​​20 mu. In the morning of autumn, during the heading period of millet, a drone was used to spray selenium-rich nutrients at one time. The spraying concentration of selenium-rich nutrients was 250ml selenium-rich nutrients / 60L water / hectare. The drone was sprayed 1.9 meters above the top of the millet. On the day of spraying selenium-rich nutrients, it should be ensured that there is no rain for 24 hours. After spraying selenium-rich fertilizers, timely irrigation is required in case of long-term drought, and the rest of the field management is carried out according to normal management. After the millet is harvested, the selenium content in the millet is sampled and tested. After testing, the average selenium content in millet is 1620μg / kg.

[0091] It can be seen that although a one-time spraying during the filling or heading period can increase the selenium content in millet, according to the provisions of "T / CATEA003-2022: Selenium Content Standard for Selenium-rich Agricultural Products" (the total selenium content in grain crops and their primary processed products in the selenium-rich agricultural products category should be in the range of 0.15-1.00 mg / kg), the method of this application can effectively accumulate organic selenium on the basis of improving the quality of millet, which meets the standard requirements and is more suitable for actual agricultural production.

[0092] The embodiments described above are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work shall all fall within the scope of protection of the present invention.

Claims

1. A method for producing selenium-enriched millet, characterized in that: The following steps are involved: (1) Preparation of selenium-enriched nutrient: using active nano-selenium-enriched technology to produce selenium-enriched nutrient; (2) Spraying selenium-rich nutrients: Spraying selenium-rich nutrients during the heading stage or early grain filling stage of millet, with the spraying concentration of selenium-rich nutrients ranging from 250 ml of selenium-rich nutrients / 60 L of water / hectare to 500 ml of selenium-rich nutrients / 60 L of water / hectare; (3) Field management: After spraying selenium fertilizer, there should be no rain within 24 hours. If there is a long-term drought, timely irrigation is required. The rest is carried out according to normal management; (4) Harvest: When all the grains turn yellow and harden, harvest them in time, dry them in the sun, thresh them and store them to obtain selenium-rich millet.

2. The method for producing selenium-enriched millet according to claim 1, characterized in that: The selenium-rich nutrient is the Nongxico nano-selenium-rich nutrient produced by using active nano-selenium-rich technology, with nano-selenium accounting for more than 98%, and the particle size of nano-selenium is 100-300 nanometers.

3. The method for producing selenium-enriched millet according to claim 1, characterized in that: The spraying amount of the selenium-rich nutrient is 20-25 g·hm -2 Se.

4. The method for producing selenium-enriched millet according to claim 1, characterized in that: The spraying amount of the selenium-rich nutrient is 22.5 g·hm -2 Se.

5. The production method according to claim 3 or 4, characterized in that: The spraying step is to apply 1 / 2 of the total spraying amount at the heading stage and the filling stage respectively.

6. A selenium-rich millet, characterized in that: The selenium-rich millet is prepared by the method described in any one of claims 1 to 5.

7. A method for increasing the β-carotene content of millet and the yellowness value of yellow millet, wherein the method comprises spraying a certain amount of selenium-rich nutrient at the heading stage and the filling stage, respectively, characterized in that: The selenium-rich nutrient agent is the Nongxike nano-selenium-rich nutrient agent produced by using active nano-selenium-rich technology, with nano-selenium accounting for more than 98%, and the particle size of nano-selenium is 100-300 nanometers.

8. The method according to claim 7, characterized in that The spraying amount of the selenium-rich nutrient is 20-25 g·hm - 2 Se.

9. A method for increasing the vitamin E content of millet, wherein the method comprises spraying a certain amount of selenium-rich nutrient at the heading stage and the filling stage, respectively, characterized in that: The selenium-rich nutrient agent is the Nongxike nano-selenium-rich nutrient agent produced by using active nano-selenium-rich technology, with nano-selenium accounting for more than 98%, and the particle size of nano-selenium is 100-300 nanometers.

10. The method according to claim 9, characterized in that The spraying amount of the selenium-rich nutrient is 20-25 g·hm -2 Se.

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