Planting method of selenium-rich purple rice

Abstract

The invention relates to the technical field of rice planting, in particular to a planting method of selenium-rich purple rice. The planting method of the selenium-rich purple rice comprises the following steps: (1) drying purple rice seeds in the sun and then disinfecting the seeds; (2) raising seedlings of the disinfected seeds and then transplanting the seedlings; (3) selenium fertilizer is applied in the early filling stage of purple rice; 0.8-1.2 L of selenium fertilizer is applied to every 15 m < 2 >; (4) nitrogen fertilizer is applied in the seedling stage of the purple rice in July. It is determined that 10 mg L <-1 > provides important reference for synergistically improving the selenium content in purple rice grains and the threshold selenium concentration of nutritional ingredients and physiological substances and for safe cultivation and nutrition enrichment of selenium-enriched rice.

Description

Technical Field

[0001] The invention relates to the technical field of rice planting, and in particular to a planting method of selenium-enriched purple rice. Background Art

[0002] Selenium (Se) is a trace element necessary for humans and animals. It is an important component of selenoproteins in the human body. It is closely related to human functions such as immunity, aging, and anti-oxidation. It plays an important role in repairing damage and improving human health. Selenium deficiency can lead to many diseases such as Kashin-Beck disease, Keshan disease, and cardiovascular disease. The human body cannot synthesize selenium directly and must obtain it through food. Therefore, selenium-rich foods can effectively supplement the selenium required by the human body and are an effective way to meet the human body's demand for selenium.

[0003] Nowadays, most soils are lacking in selenium. In addition, some selenium-rich areas have low selenium effectiveness due to acidic soil, which makes it difficult for plants to absorb, and the selenium content in crop products is generally low. Selenium biofortification is an important strategy to reduce hidden hunger and increase the nutritional intake of the population. People usually use exogenous selenium to increase the selenium content in crop products. Purple rice is rich in physiologically active substances and nutrients and has certain health functions. The selenium content of Chinese selenium-rich rice is between 40-300 μg / kg, and the selenium content of rice exceeds 300 μg / kg, which is not suitable for consumption. Although some preliminary studies have shown that the exogenous application of selenium can have a positive effect on the growth and nutritional value of rice, the technology for synergistically improving the selenium content, main nutrients and physiologically active substances of purple rice is not yet mature, and lacks systematic research and in-depth mechanism exploration. The present invention is to further clarify the exogenous selenium spraying threshold for synergistically improving the selenium content, nutrients and physiologically active substances of purple rice. In order to provide a reference basis for the safe production of selenium-rich rice and the cultivation of high-nutrition rice. Summary of the invention

[0004] The purpose of the present invention is to provide a method for planting selenium-rich purple rice. The method comprises dissolving selenium reagents of different concentrations in a certain amount of water and spraying the selenium reagents on rice plants in the early stage of purple rice filling in the form of exogenous spraying, thereby synergistically improving the selenium element, main nutrients and physiologically active substances in purple rice grains.

[0005] In order to achieve the above objectives, the present invention provides the following technical solutions:

[0006] The present invention provides a method for planting selenium-enriched purple rice, comprising the following steps:

[0007] (1) Drying and disinfecting purple rice seeds;

[0008] (2) raising the sterilized seeds and then transplanting them;

[0009] (3) Apply selenium fertilizer at the early stage of purple rice filling; every 15m 2 Apply 0.8-1.2L of selenium fertilizer;

[0010] (4) Apply nitrogen fertilizer during the purple rice seedling stage in July.

[0011] Preferably, the disinfection method in step (1) is seed soaking disinfection, the agent for seed soaking disinfection is Liangdun, and the time for seed soaking disinfection is 10 to 12 hours.

[0012] Preferably, the seedling raising method of step (2) is blanket seedling raising, and the seed amount per mu is 3-4 kg.

[0013] Preferably, the transplanting time in step (2) is mid-June, and the seedlings are 22 to 26 days old at the time of transplanting.

[0014] Preferably, the transplanting method in step (2) is planting, the planting row spacing is 12×30 cm, and 3 to 6 seedlings are planted in each hole.

[0015] Preferably, the selenium fertilizer in step (3) is Na2SeO3, and the concentration of the selenium fertilizer is 10 to 40 mg / L.

[0016] Preferably, the selenium fertilizer is sprayed on the leaves.

[0017] Preferably, the nitrogen fertilizer in step (4) is urea, and the nitrogen fertilizer is applied in an amount of 240 to 300 kg / hm2 in terms of pure nitrogen. 2 .

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention compares Se0, Se10, Se20 and Se40 to analyze the difference of selenium content and antioxidant capacity of purple rice grains after exogenous spraying of selenium fertilizer. It is concluded that under different concentrations of exogenous selenium, there are differences in selenium content, total antioxidant capacity, antioxidant enzyme activity and the like of purple rice grains. Compared with Se0, the selenium content of Se10, Se20 and Se40 after spraying selenium is significantly increased. According to the measurement results of three methods of total antioxidant capacity (ABTS method, DPPH method and FRAP method), the total antioxidant capacity of Se10 and Se20 is significantly enhanced compared with Se0, while the total antioxidant capacity of Se40 is not significant compared with Se0. Compared with Se0, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of Se10, Se20 and Se40 are improved, all showing a trend of first rising and then falling, and reaching the highest in Se20. From the above analysis, it can be concluded that after spraying exogenous selenium, the selenium content and total antioxidant capacity of purple rice grains generally increased, and the antioxidant capacity of purple rice grains showed a trend of first increasing and then decreasing, which shows that exogenous selenium can indeed significantly improve the antioxidant capacity of purple rice grains, but too high selenium concentration will reduce the antioxidant capacity of purple rice grains. In addition, the selenium content of purple rice grains under Se10 treatment alone is within the standard range of Chinese selenium-rich rice. Therefore, in comparison, Se10 treatment has higher reference significance and practical value.

[0020] By analyzing the differences in physiologically active substances and nutritional components of purple rice grains under exogenous selenium, it was found that with the increase of selenium concentration, the content of reduced ascorbic acid (AsA) / vitamin C, flavonoids (Fd), proanthocyanidins (OPC), and total phenols (TP) increased, while the content of crude protein (CP), crude fat (CF), total sugar (TS), sucrose (Sucrose), and glucose (Glucose) showed a significant trend of first increasing and then decreasing. Among them, the physiologically active substances and nutritional components of purple rice grains under Se10 treatment were higher than those under Se0.

[0021] Through the differential analysis of the amino acid content of purple rice grains under exogenous selenium, it was found that the content of most amino acids in purple rice grains treated with Se20 was significantly different from that of the corresponding amino acids treated with Se0, Se10, and Se40. In addition, the content of most amino acids showed a trend of first increasing and then decreasing under the treatment of increasing exogenous selenium concentrations, and the corresponding amino acid content of Se20 treatment was the highest point among the four treatments, which shows that exogenous selenium has the effect of promoting amino acid synthesis at low concentrations and inhibiting it at high concentrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a process flow chart of purple rice grains after exogenous spraying of selenium fertilizer in the present invention;

[0023] Figure 2The selenium content and antioxidant capacity of purple rice grains under exogenous selenium in Example 1; wherein, (a) selenium content; (b) ABTS value; (c) DPPH value; (d) FRAP value; (e) superoxide dismutase (SOD) activity; (f) peroxidase (POD) activity; (g) catalase (CAT) activity; (h) malondialdehyde (MDA) content; (i) soluble protein (Cpr) content; different lowercase letters represent significance at the 0.05 level;

[0024] Figure 3 The physiologically active substances and nutritional components of purple rice grains under exogenous selenium in Example 1; wherein (a) reduced ascorbic acid (AsA) / vitamin C content (AsA content); (b) flavonoid content (Fd content); (c) proanthocyanidin content (OPC content); (d) total phenol content (TP content); (e) crude protein (CP content); (f) crude fat (CF); (g) total sugar (TS content); (h) sucrose (Sucrose content); (i) glucose (Glucose content); different lowercase letters represent significance at the 0.05 level. DETAILED DESCRIPTION

[0025] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0026] The present invention provides a method for planting selenium-rich purple rice, comprising the following steps: using the experimental material Yang Zi Nuo No. 2 (a new plant variety right has been applied for, application number 20211007720) independently cultivated by the Rice Industry Engineering Technology Research Institute of Yangzhou University for experiment, sowing on May 20, 2023, drying the seeds for 1 to 2 days before sowing, soaking the seeds with drugs for disinfection for 10 to 12 hours, and then breeding the seedlings in seed trays. The sowing method is blanket seedlings, the sowing amount per tray is 120g, the seed amount per mu is 3.5kg, and the seedlings are concentrated after darkening for 3 days. In a specific embodiment of the present invention, the seed soaking agent is Liangdun.

[0027] Before transplanting, the land was cultivated, the plots were divided and processed, deep plowing and land preparation were carried out, stemming was done, plastic film was covered and water was irrigated. When the seedling age of Yang Zi Nuo No. 2 reached 25 days, it was transplanted to the Shatou Base of Yangzhou University in Yangzhou City, Jiangsu Province. The planting spacing was 12×30cm, and 4 seedlings were planted in each hole.

[0028] Four selenium concentration spraying treatments were set up, and the selenium fertilizer was Na2SeO3 reagent. Selenium fertilizer was sprayed at the early stage of purple rice filling (see Figure 1 ), the selenium concentrations were Se0 (spraying water control, Se concentration 0mg L-1 )、Se10(Se concentration 10mg L -1 )、Se20(Se concentration 20mg L -1 )、Se40(Se concentration 40mg L -1 ). Shake the selenium solution before spraying, and spray it evenly on the leaves of Yang Zi Nuo No. 2 after 16:00 on a sunny day;

[0029] Each treatment was repeated three times, with a total of 12 plots arranged in random blocks, with a plot area of ​​15 m 2 , and protection rows are set up around the plot. Urea is used as nitrogen fertilizer in the field, with a total of 270 kg / hm2 of pure nitrogen 2 .

[0030] Preparation before the experiment:

[0031] Seeds: Purple rice Yangzinuo No. 2 bred by the Rice Industry Research Institute of Yangzhou University (germination rate ≥ 94%, purity ≥ 99%);

[0032] Substrate, seedling tray: The organic matter content of the conventional purchase is ≥46%, and the size of the seedling tray is 60cm×25cm;

[0033] Reagents: Na2SeO3 purchased routinely;

[0034] Seed soaking agent: Liangdun (25g / L of fludioxonil and 37.5g / L of metalaxyl).

[0035] Water for soaking seeds: purified water.

[0036] Example 1

[0037] 1. A method for growing selenium-enriched purple rice, comprising the following steps:

[0038] (1) Seed soaking: In mid-May, the seeds of Yang Zi Nuo No. 2 (independently bred by the Rice Industry Engineering and Technology Research Institute of Yangzhou University, which has applied for new plant variety rights, application number 20211007720) were first exposed to the sun for 2 days before sowing, and then soaked in drugs for disinfection for 12 hours to obtain soaked seeds.

[0039] (2) Raising seedlings: Sow the soaked seeds in blanket seedling cultivation at a density of 100 g per tray and incubate in the dark for 3 days.

[0040] (3) Land preparation before sowing: Before transplanting rice seedlings, the land should be plowed, the field should be prepared, divided into plots and ridges should be made, and the ridges should be covered with plastic film.

[0041] (4) Transplantation: The transplanting time is mid-June, and the seedlings are transplanted at 25 days old. They are transplanted at the Shatou Base of Yangzhou University in Yangzhou City, Jiangsu Province. The planting spacing is 12×30 cm, and 4 seedlings are planted in each hole.

[0042] (5) Selenium fertilizer was sprayed on purple rice at the early stage of grain filling. Four selenium concentrations were set for spraying. The selenium fertilizer was Na2SeO3 reagent. The selenium concentrations were Se0 (spraying water control, Se concentration 0 mg L -1 )、Se10(Se concentration 10mg L -1 )、Se20(Se concentration 20mgL -1 )、Se40(Se concentration 40mg L -1 ). Shake the selenium solution before spraying and spray it evenly on the rice after 16:00 on a sunny day. There are 4 treatments, each with 3 replicates, a total of 12 plots, and the application rate is 1L of selenium fertilizer in each plot. The random block arrangement is adopted, and the plot area is 15m 2 The field was uniformly fertilized with nitrogen fertilizer in July at the purple rice seedling stage as basal fertilizer. The nitrogen fertilizer used was urea, with a total of 270 kg / hm2 of pure nitrogen. 2 .

[0043] (6) After the rice matures and is harvested, the grains of each treatment are collected from the field, quickly frozen in liquid nitrogen and immediately brought back to the laboratory. After the rice husks are peeled with tweezers, the grain samples are collected and stored at -80°C for further testing.

[0044] 2. Effects of exogenous spraying of different concentrations of selenium fertilizer on the selenium content and antioxidant capacity of purple rice grains

[0045] The present invention compares Se0, Se10, Se20 and Se40 to analyze the differences in selenium content and antioxidant capacity of purple rice grains after spraying selenium fertilizer exogenously ( Figure 2). It was found that compared with Se0, the Se content of Se10, Se20 and Se40 increased significantly. The definition of selenium-rich rice in GB / T22499-2008 "Selenium-enriched Rice" is 40-300μg / kg (Fig. 2a). The total antioxidant capacity of purple rice grains was determined by the ABTS method. The ABTS values ​​of Se10 and Se20 were significantly higher than Se0, and the ABTS value of Se40 was not significantly different from Se0 (Fig. 2b). The total antioxidant capacity of purple rice grains was determined by the DPPH method. The DPPH values ​​of Se10 and Se20 were significantly higher than Se0, and the DPPH value of Se40 was significantly lower than Se0 (Fig. 2c). The total antioxidant capacity of purple rice grains was determined by the FRAP method. The FRAP values ​​of Se10 and Se20 were significantly higher than Se0, and the FRAP value of Se40 was not significantly different from Se0, which was consistent with the results of the ABTS method (Fig. 2d). Combining the results of the three methods of ABTS, DPPH and FRAP, the total antioxidant capacity of Se10 and Se20 was significantly enhanced compared with Se0, while the total antioxidant capacity of Se40 was not significantly different from that of Se0. Compared with Se0, the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) of Se10, Se20 and Se40 were improved, all showing a trend of first increasing and then decreasing, and reached the highest in Se20 (Fig. 2e, f, g). The superoxide dismutase (SOD) activity of Se20 was significantly higher than that of Se0, Se10 and Se40 (Fig. 2e). The peroxidase (POD) and catalase (CAT) activities of Se10, Se20 and Se40 were significantly higher than those of Se0 (Fig. 2f, g). Malondialdehyde (MDA) is an important product of lipid peroxidation and is usually used as an indirect indicator for measuring oxidative damage. The higher the content, the weaker the antioxidant capacity. The malondialdehyde (MDA) content of Se10 and Se20 was significantly lower than that of Se0, and the malondialdehyde (MDA) content of Se40 was significantly higher than that of Se0, among which the malondialdehyde (MDA) content of Se20 was the lowest (Fig. 2h). The soluble protein (Cpr) content of Se10 and Se20 was significantly higher than that of Se0, and there was no significant difference between the soluble protein (Cpr) content of Se40 and that of Se0 (Fig. 2i). From the above analysis, it can be concluded that after spraying exogenous selenium, the selenium content and total antioxidant capacity of purple rice grains generally increased, and the antioxidant capacity of purple rice grains showed a trend of first increasing and then decreasing, which shows that exogenous selenium can indeed significantly improve the antioxidant capacity of purple rice grains, but too high selenium concentration will reduce the antioxidant capacity of purple rice grains. In addition, only the selenium content of purple rice grains under Se10 treatment was within the standard range of selenium-rich rice. Therefore, it was determined that 10 mg L -1 In order to synergistically improve the selenium content, nutritional components and threshold selenium concentration of physiological substances in purple grains, it provides an important reference for the safe cultivation and nutritional enrichment of selenium-enriched rice and has great practicality.

[0046] 3. Effects of spraying different concentrations of selenium fertilizer on physiologically active substances and nutritional components in purple rice grains

[0047] The kit of the present invention was purchased from Suzhou Mengxi Biomedical Technology Co., Ltd. (Suzhou Mengxi Biomedical Technology Co., Ltd., Suzhou, China). The kit was used according to the instructions to determine the flavonoid (FD) content, oligomeric proanthocyanidin (OPC) content, total phenol (TP) content, reduced ascorbic acid (AsA) / vitamin C and total antioxidant capacity (ABTS, DPPH and FRAP method), catalase (CAT) activity, peroxidase (POD) activity, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, soluble protein (Cpr) content, total sugar (TS) content, sucrose (Sucrose) content, glucose (Glucose) content, crude protein (CP) content, crude fat (CF) content. The brief determination methods of some indicators are as follows.

[0048] The soluble protein content was determined using the BCA method: 0.1000 g of seeds were weighed, 1 mL of distilled water was added, and the mixture was homogenized in an ice bath. Centrifuged at 12000 rpm and 4°C for 10 min, and the supernatant was placed on ice for testing. The microplate reader was preheated for 30 min, and the measurement wavelength was 562 nm.

[0049] Sucrose content determination method: weigh 0.1000g of seeds, grind at room temperature; add 1mL of extract, grind appropriately and quickly transfer to a covered centrifuge tube; place in an 80℃ water bath for 10min, then add a small amount (2mg) of reagent V, decolorize at 80℃ for 30min (cover tightly to prevent water loss, shake 2-3 times during the period); centrifuge at 4000g, 25℃ for 10min, take the supernatant for determination. Place in a 95℃ water bath for 30min, cool and take 200μL of the reaction solution in a 96-well plate to determine the absorbance of each tube at 480nm.

[0050] Glucose content determination method: weigh 0.1000g of seeds, add 1mL of distilled water, grind into a homogenate, place in a 95℃ water bath for 10min (cover tightly to prevent water loss), cool, centrifuge at 8000g, 25℃ for 10min, take the supernatant for later use, keep at 25℃ for 15min, and read the absorbance at a wavelength of 505nm.

[0051] Method for determination of malondialdehyde content: weigh 0.1000g of seeds, add 1mL of extract, and homogenize at room temperature. Centrifuge at 10000rpm for 10min at room temperature, take the supernatant, and test. Water bath at 92℃ for 30min (close the lid tightly to prevent water loss), cool, centrifuge at 12000rpm, 25℃ for 10min. Take 200μL of supernatant in a 96-well plate, and measure the absorbance at 532nm and 600nm.

[0052] The present invention has found that the physiologically active substances and nutritional components of purple rice grains are different under different concentrations of exogenous selenium (see Figure 3 ). The reduced ascorbic acid (AsA) / vitamin C content of Se10, Se20, and Se40 was significantly higher than that of Se0, among which Se20 had the highest reduced ascorbic acid (AsA) / vitamin C content (Fig. 3a). There was no significant difference in the flavonoid (Fd) content and proanthocyanidin (OPC) content among Se0, Se10, Se20, and Se40, but the flavonoid (Fd) content and proanthocyanidin (OPC) content of Se10, Se20, and Se40 were higher than those of Se0 (Fig. 3b, c). There was no significant difference in the total phenol (TP) content of Se10 and Se20 compared with Se0, and the total phenol (TP) content of Se40 was significantly higher than that of Se0 (Fig. 3d). There was no significant difference in the crude protein (CP) content of Se10, Se20, and Se40 compared with Se0, but the crude protein (CP) content of Se10 was significantly higher than that of Se40 (Fig. 3e). The crude fat (CF) and total sugar (TS) contents of Se10 and Se20 were significantly higher than those of Se0, while the crude fat (CF) of Se40 was significantly lower than that of Se0. There was no significant difference in the crude fat (CF) of Se20 and Se10, but the total sugar (TS) content of Se20 was significantly higher than that of Se10 (Fig. 3f, g). The sucrose content of Se10 was significantly higher than that of Se0, while there was no significant difference in the sucrose content of Se20 and Se40 compared with Se0 (Fig. 3h). The glucose content of Se10 was significantly higher than that of Se0, while the glucose content of Se20 and Se40 was significantly lower than that of Se0 (Fig. 3i). The results showed that with the increase of Se concentration, the contents of reduced ascorbic acid (AsA) / vitamin C, flavonoids (Fd), proanthocyanidins (OPC) and total phenols (TP) showed an upward trend, while the contents of crude protein (CP), crude fat (CF), total sugar (TS), sucrose (Sucrose) and glucose (Glucose) showed a significant trend of first increasing and then decreasing. Among them, the physiologically active substances and nutritional components of purple rice grains under Se10 treatment were higher than those under Se0.

[0053] 4. Effect of exogenous spraying of different concentrations of selenium fertilizer on the amino acid content of purple rice grains

[0054] Accurately weigh 19 kinds of amino acid standards, dissolve them in 0.1M HCl water and dilute to 1mL, vortex to mix, and obtain standard stock solution. Prepare L-Trp-d5, L-Gln-d5, and L-Lys-d4 solutions with 25mM TCA water to 100μg / mL. Take the above mixed standard solution and dilute it with 25mM TCA aqueous solution to 10 working solutions of different concentrations, and use 400ng / mL three mixed standard solutions to dilute the above working solutions in equal volumes to obtain the injection standard solution, which is placed in the injection vial for LC-MS detection and analysis.

[0055] Accurately weigh 20 mg of seeds, add 141 μL of water, 100 μL of 0.15% DOC and mix well, add 4 μL of 100 μg / mL triple internal standard solution (Lys-d4 / Try-d5 / Gln-d4), mix well and ultrasonicate for 10 min (5°C, 40KHz), add 5 μL of 10M trichloroacetic acid (TCA) and mix well, freeze the sample and let it settle for 10 min, centrifuge at 4°C and 10000g for 10 min, take 25 μL of supernatant, add 375 μL of water, vortex to mix well, and pass through a biotage 0.2 μm PTFE filter.

[0056] This experiment uses LC-ESI-MS / MS (UHPLC-Qtrap) to perform qualitative and quantitative detection of amino acids in samples. The specific parameters are as follows:

[0057] Chromatographic conditions: AdvanceBio MS SpentMedia, (2.1*50mm, 2.7μm), column temperature 40°C, injection volume 1μL. Mobile phase A (0.1% formic acid 10mM ammonium formate 95% aqueous solution), mobile phase B (0.1% formic acid 10mM ammonium formate 95% acetonitrile solution).

[0058] Mass spectrometry conditions: SCIEX QTRAP 6500+, positive / negative mode detection, Curtain Gas (CUR) was 35, Collision Gas (CAD) was Medium, IonSpray Voltage (IS) was +5500 / -4500, Temperature (TEM) was 550, Ion Source Gas1 (GS1) was 50, and Ion Source Gas2 (GS2) was 50.

[0059] The present invention detected that the amino acid content of purple rice grains was different under different concentrations of exogenous selenium (see Table 1). The alanine content of Se10, Se20, and Se40 was significantly lower than that of Se0, decreasing by 14.58%, 20.79%, and 10.65%, respectively. The arginine content of Se20 was the highest, 36.14%, 26.82%, and 36.77% higher than that of Se0, Se10, and Se40, respectively, and the difference was significant.

[0060] The aspartic acid content of Se10 was significantly higher than that of Se0, and the aspartic acid content of Se40 was significantly lower than that of Se0. The glutamine and glutamic acid contents of Se20 were significantly higher than those of Se0, Se10, and Se40, among which the glutamine content of Se40 was the lowest, and the glutamic acid content of Se0 was the lowest. The glycine content of Se10 was significantly lower than that of Se0, Se20, and Se40. The histidine content of Se20 was significantly higher than that of Se0, Se10, and Se40. The isoleucine content of Se10 and Se20 was significantly higher than that of Se0 and Se40. The leucine content of Se20 was significantly higher than that of Se0, Se10, and Se40, and the leucine content of Se40 was the lowest. The hydroxyproline content of Se10 and Se20 was significantly lower than that of Se0, decreasing by 25.93% and 22.22%, respectively. The tryptophan content of Se10 and Se20 was lower than that of Se0, and the tryptophan content of Se40 was higher than that of Se0, and significantly higher than that of Se10 and Se20. The lysine content of Se10 and Se20 was significantly higher than that of Se0, and that of Se40 was significantly lower than that of Se0. The methionine content of Se10 and Se20 was higher, which was 5.84% and 18.74% higher than that of Se0, respectively. The phenylalanine content of Se10 and Se20 was significantly higher than that of Se0, which was 21.04% and 72.60% higher, respectively. The proline content of Se20 was the highest, which was 20.46%, 19.20% and 31.71% higher than that of Se0, Se10 and Se40, respectively. The serine content of Se20 was the highest, which was 62.72%, 39.85% and 41.04% higher than that of Se0, Se10 and Se40, respectively, with significant differences.

[0061] The serine content of Se10, Se20 and Se40 were all higher than that of Se0. The threonine content of Se0 was the lowest, and that of Se20 was the highest, which was 30.60%, 18.52% and 21.28% higher than that of Se0, Se10 and Se40, respectively. The tyrosine content of Se40 was the lowest, and that of Se20 was the highest, which was 38.58% higher than that of Se0. The valine content of Se40 was significantly lower than that of Se0, which was 13.17% lower. The valine content of Se20 was the highest, which was 30.06%, 26.59% and 49.78% higher than that of Se0, Se10 and Se40, respectively.

[0062] In general, the contents of most amino acids in purple rice grains treated with Se20 were significantly different from those in Se0, Se10, and Se40. In addition, the contents of most amino acids showed a trend of first increasing and then decreasing under the treatment of increasing exogenous Se concentration, and the corresponding amino acid content in Se20 treatment was the highest point among the four treatments, which indicates that exogenous selenium has the effect of promoting amino acid synthesis at low concentrations and inhibiting it at high concentrations.

[0063] Table 1 Difference analysis of amino acid content in purple rice grains under exogenous Se

[0064]

[0065]

[0066] Note: The unit of amino acid content is (ng mg -1 Different lowercase letters indicate significant differences at the P = 0.05 level.

[0067] Based on the above data, it can be concluded that with the increase of exogenous selenium concentration, the selenium content and physiologically active substance content of purple rice grains are both on the rise, while the nutrients, most amino acids and total antioxidant capacity are on the rise first and then on the decline. The total antioxidant capacity of Se10, Se20 and Se40 is improved compared with Se0. These basic data provide information for future metabolomics and multi-omics assisted breeding. The present invention finds that Se10 is the exogenous selenium spraying threshold for the synergistic improvement of purple rice selenium element, main nutrients and physiologically active substances, which provides a reference basis for the current safe application of exogenous selenium in rice, and provides a reference value for the precision of the exogenous selenium spraying threshold for the synergistic improvement of purple rice selenium element, main nutrients and physiologically active substances in the future.

[0068] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for planting selenium-enriched purple rice, characterized in that: The following steps are involved: (1) Drying and disinfecting purple rice seeds; (2) raising the sterilized seeds and then transplanting them; (3) Apply selenium fertilizer at the early stage of purple rice filling; every 15m 2 Apply 0.8-1.2L of selenium fertilizer; (4) Apply nitrogen fertilizer during the purple rice seedling stage in July.

2. The planting method according to claim 1, characterized in that: The disinfection method of step (1) is seed soaking disinfection, the agent of seed soaking disinfection is Liangdun, and the time of seed soaking disinfection is 10 to 12 hours.

3. The planting method according to claim 1, characterized in that: The seedling raising method of step (2) is blanket seedling raising, and the seed amount per mu is 3-4 kg.

4. The planting method according to claim 1, characterized in that: The time for transplanting in step (2) is mid-June, and the seedlings are 22 to 26 days old when transplanted.

5. The planting method according to claim 1 or 4, characterized in that: The transplanting method in step (2) is planting, the planting row spacing is 12×30 cm, and 3 to 6 seedlings are planted in each hole.

6. The planting method according to claim 1, characterized in that: The selenium fertilizer in step (3) is Na2SeO3, and the concentration of the selenium fertilizer is 10-40 mg / L.

7. The planting method according to claim 1 or 6, characterized in that: The selenium fertilizer is sprayed on leaves.

8. The planting method according to claim 1, characterized in that: The nitrogen fertilizer in step (4) is urea, and the nitrogen fertilizer is applied in an amount of 240 to 300 kg / hm2 in terms of pure nitrogen. 2 .

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