Application of selenium-containing carbon quantum dots in strengthening organic selenium accumulation in rice grains

Abstract

This invention discloses the application of selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains, belonging to the field of plant growth regulator technology. This invention provides the application of selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains, which can significantly increase the organic selenium content in rice grains, including selenocysteine, selenomethionine, and methylselenocysteine. Under high and low temperature conditions during the rice grain-filling stage, the selenium-containing carbon quantum dots significantly increase the accumulation of total organic selenium, thereby stably improving the organic selenium level of rice grains under different temperature stresses, ensuring the nutritional quality and functionality of rice. This invention provides an efficient and stable method for producing selenium-enriched functional rice.

Description

Technical Field

[0001] This application belongs to the field of plant growth regulator technology, and in particular relates to the application of selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains. Background Technology

[0002] Selenium is an essential trace element for the human body, possessing various physiological functions such as antioxidation, immune enhancement, and cancer prevention. The human body primarily obtains selenium through diet, with plants being the main pathway for selenium to enter the food chain. Therefore, increasing the selenium content in crop grains through agricultural methods, especially through highly bioactive and safe organic selenium forms (selenocysteine, selenomethionine, and methylselenocysteine), has become an important direction for the production of functional selenium-enriched agricultural products.

[0003] Currently, the selenium sources commonly used in selenium-fortified agriculture mainly include inorganic selenium (such as sodium selenite and sodium selenate) and organic selenium fertilizers (cysteine, selenomethionine, and methylselenocysteine). However, these traditional selenium fertilizers still have several limitations in practical applications: although inorganic selenium is inexpensive, it has low bioavailability and high toxicity, and excessive use can easily cause soil pollution and selenium poisoning in plants; organic selenium fertilizers are more expensive, and their promoting effect on plant selenium absorption and conversion under adverse conditions (such as high and low temperatures) is unstable, especially in cereal crops such as rice where the accumulation efficiency of organic selenium is not high.

[0004] In recent years, selenium nanomaterials have shown potential in agricultural selenium fortification due to their high bioactivity, low toxicity, and good biocompatibility. Existing research indicates that selenium-containing carbon quantum dots (Se-CDs), as a novel type of selenium nanomaterial, can effectively enhance plant biomass and growth under abiotic stress, improve photosynthetic capacity, and increase plant resistance by regulating reactive oxygen species (ROS) homeostasis and maintaining the integrity of intracellular membrane systems, through foliar spraying or root application. However, current technologies mainly focus on the general promoting effects of Se-CDs on plant growth and stress resistance; their application in the targeted fortification of organic selenium forms in specific crops—especially rice—grains has not been systematically reported. In particular, the regulatory effects on the accumulation of selenoamino acids under different grain-filling temperatures and their synergistic enhancement mechanism with grain setting remain unexplored.

[0005] Therefore, in view of the limited effect of existing selenium fertilizers on promoting the accumulation of organic selenium in rice grains under high or low temperature adverse conditions and the low efficiency of selenium form conversion, this invention provides an application of selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains, which has important research significance and application value, and provides an efficient, stable and environmentally friendly method for producing high-quality selenium-enriched rice. Summary of the Invention

[0006] To address the technical problems existing in the prior art, the primary objective of this invention is to provide an application of selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains.

[0007] Another object of the present invention is to provide the application of the above-mentioned selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains at high temperatures during the mid-grain filling stage.

[0008] Another object of the present invention is to provide the application of the above-mentioned selenium-containing carbon quantum dots in enhancing the accumulation of selenocystine in rice grains at high temperatures during the mid-grain filling stage.

[0009] Another object of the present invention is to provide a method for rice cultivation using the above-mentioned selenium-containing carbon quantum dots.

[0010] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0011] This invention protects the application of selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains.

[0012] Our research group previously developed a novel selenium-containing carbon quantum dots (Se-CDs) in a patent (CN115029138A). This nanomaterial, applied via foliar spraying or root application, effectively enhances plant biomass and growth under abiotic stress, strengthens photosynthetic capacity, and significantly improves plant resistance by regulating reactive oxygen species homeostasis and maintaining the integrity of intracellular membrane systems. However, current research primarily focuses on the general promoting effects of Se-CDs on plant growth and stress resistance, and has not yet systematically revealed its potential and mechanisms for the targeted accumulation of organic selenium in crop grains.

[0013] Building upon this foundation, this invention further reveals that applying selenium-containing carbon quantum dots (Se-CDs) to rice cultivation significantly promotes the accumulation of organic selenium (including selenocysteine, selenomethionine, and methylselenocysteine) in the grains. The mechanism of action lies in the fact that Se-CDs, due to their nanoscale effect and surface-active groups, are more easily absorbed by rice leaves and transported to the grains. Simultaneously, they act as selenium carriers and slow-release agents within the plant, promoting the efficient conversion of inorganic selenium to organic selenium. Furthermore, Se-CDs enhance the activity of the antioxidant system and stabilize cell membrane structure, alleviating the inhibition of selenium metabolism pathways by stresses such as high or low temperatures, thereby ensuring the synthesis and accumulation of selenoamino acids. This discovery provides a new technical approach and basis for using nanomaterials to directionally increase the organic selenium content of rice grains.

[0014] Preferably, the rice is colored rice and / or white rice.

[0015] Preferably, the colored red rice variety is Luotian red rice.

[0016] Preferably, the conventional white rice variety is Yangdao No. 6.

[0017] Preferably, the organoselenium comprises one or more of selenocysteine, methylselenocysteine, or selenomethionine.

[0018] Preferably, the selenium-containing carbon quantum dots are prepared by the following method: selenocysteine ​​hydrochloride and m-phenylenediamine are mixed in ultrapure water and reacted at 120-200°C for 6-12 hours under anaerobic conditions. After purification, a nanomaterial colloid containing selenium-containing carbon quantum dots is obtained; the mass ratio of selenocysteine ​​hydrochloride to m-phenylenediamine is 2-3:1.

[0019] Preferably, the preparation method of selenized carbon quantum dots includes the following steps: mixing selenocysteine ​​hydrochloride and m-phenylenediamine in ultrapure water, reacting at 180°C for 10 h under anaerobic conditions, and purifying to obtain a nanomaterial colloid containing selenized carbon quantum dots; wherein the mass ratio of selenocysteine ​​hydrochloride to m-phenylenediamine is 2:1.

[0020] Preferably, the purification is performed using high-speed centrifugation.

[0021] Application of selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains at high temperatures during the mid-grain-filling stage.

[0022] Preferably, the high temperature during the mid-grouting stage is an average temperature of 33°C or higher 9 to 15 days after rice flowering.

[0023] Preferably, the organoselenium is selenomethionine.

[0024] Application of selenium-containing carbon quantum dots in enhancing the accumulation of selenocystine in rice grains under high temperature during the mid-grain filling stage.

[0025] Selenocysteine ​​is a hallmark organoselenium compound of rice stress resistance. It is an oxidized selenium-containing amino acid characterized by a diselenyl bond. In plants, it mainly functions as a key intermediate in the selenium metabolic pathway, and its accumulation level is closely related to the ability of rice plants to cope with abiotic stress.

[0026] A method for rice cultivation includes spraying selenium-containing carbon quantum dots once during the third stage of rice panicle differentiation and once on the day of heading.

[0027] Preferably, the application concentration of the selenium-containing carbon quantum dots is 1~10 mg / L.

[0028] More preferably, the application concentration of the selenium-containing carbon quantum dots is 5 mg / L.

[0029] Compared with the prior art, the present invention has the following beneficial effects: This application improves the application of selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains, effectively promoting the accumulation of organic selenium components in rice grains, thereby significantly increasing the organic selenium content of rice, providing a reliable technical means for producing high-value-added functional nutritional rice, and enhancing the stress resistance of rice; furthermore, under high temperature and low temperature conditions during the grain-filling stage, selenium-containing carbon quantum dots significantly increase the accumulation of total organic selenium in rice, thereby stably increasing the organic selenium level of rice grains under different temperature stresses, ensuring the nutritional quality and functionality of rice. Attached Figure Description

[0030] Figure 1 The diagram shows the metabolic relationships of three selenoamino acids, highlighted in red: Sec-Sec represents selenocysteine, MeSeCys represents methylselenocysteine, and SeMet represents selenomethionine. Detailed Implementation

[0031] The present invention is further illustrated below with reference to specific embodiments. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions in the art or as recommended by the manufacturer; the raw materials and reagents used, unless otherwise specified, are all commercially available from the conventional market. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention are within the scope of protection claimed by the present invention.

[0032] I. The reagents used in the various embodiments and comparative examples of this invention are described below: Selenized carbon quantum dots (Se-CDs): The preparation method is as follows: Take 500 ml of pure water, add 5.0 g of selenocysteine ​​dihydrochloride and 2.5 g of m-phenylenediamine, wherein the mass ratio of selenocysteine ​​hydrochloride to m-phenylenediamine is 2:1; after complete dissolution, transfer the solution to a reaction vessel, place it in an oven, set the temperature to 180℃, and the time to 10 h. After cooling, dispense into 50 ml centrifuge tubes, centrifuge at 12000 g for 5 min, discard the precipitate, and the supernatant is the prepared sample, and the concentration is determined.

[0033] Luotian Red Rice, a colored red rice variety, is abbreviated as RR.

[0034] Yangdao No. 6, a common white rice variety, is also known as 9311.

[0035] II. Test Indicators: Selenized amino acid samples were submitted: selenocysteine ​​(SeC-SeC); selenomethionine (Se-Met); methylselenocysteine ​​(MeSeCys). Each sample was tested according to the examples or comparative examples, with 3 replicates for each.

[0036] III. Examples / Comparative Examples: Example 1 In a study on the RR pot cultivation of Luotian red rice, foliar spraying of Se-CDs with a selenium content of 5 mg / L, traditional selenium fertilizer, sodium selenite Na2SeO3, and ddH2O was used as the control group. The spraying treatment was carried out once each during the booting stage (ear differentiation stage III) and the heading stage (70% of the plants were heading).

[0037] Different temperature treatments (high temperature HT and low temperature LT) were applied during the mid-grain filling stage (9 to 15 days after flowering). The grains were then allowed to mature naturally. The contents of selenocystine (Cys-Se-Se-Cys), methylseleno-L-cysteine ​​(Se-me-Cys), and selenomethionine (Se-Met) in grains sampled 15 days after flowering were tested.

[0038] (1) Potted high temperature group - average temperature 33℃, temperature range 27~37℃, light 14 hours; (2) Potted low temperature group - average temperature 20℃, temperature range 15~25℃, light 14 hours.

[0039] The experimental results are shown in Tables 1 and 2: Table 1. Organic selenium accumulation in red rice under high and low temperatures during the mid-grain-filling stage.

[0040] Table 2. Accumulation of organic selenium types in red rice under high and low temperatures during the mid-grain-filling stage.

[0041] Table 1 shows that grain-filling temperature significantly affects the accumulation of organic selenium in red rice, specifically the accumulation of selenomethionine content. Under high-temperature conditions during the mid-grain-filling stage, the contents of selenocysteine, methylselenocysteine, and selenomethionine in red rice grains significantly increased, with increases of 72.8%, 5.4%, and 76.2% respectively compared to the control group (H2O). Under low-temperature conditions during the mid-grain-filling stage, Se-CDs mitigated the adverse effects of low temperature on selenium accumulation, significantly increasing the total accumulation of organic selenium, especially promoting the accumulation of selenomethionine in grains, thereby improving nutritional quality. In other words, carbon-containing quantum dots significantly increased the total accumulation of organic selenium compared to traditional selenium fertilizer Na2SeO3 at both high and low temperatures.

[0042] The accumulation amounts of different types of organic selenium in Table 2 were calculated using the average accumulation amounts of organic selenium in Table 1. Table 2 illustrates the regulatory effect of selenium-containing carbon quantum dots (Se-CDs) on the distribution of organic selenium speciation in red rice grains under different grain-filling temperatures. "Selenocysteine ​​+ methylselenocysteine" represents oxidized diselenylene bonds and reduced selenools, belonging to antioxidant / stress-responsive organic selenium; "selenomethionine" represents storage-type methylselenoyl organic selenium, a nutrient-accumulating organic selenium. At high temperatures during the mid-grain-filling stage, Se-CDs promoted the synthesis and accumulation of antioxidant organic selenium, helping to enhance the antioxidant capacity of rice grains under high-temperature stress. The total amount of "selenocysteine ​​+ methylselenocysteine" in the Se-CDs-treated group was 3128.76 ng / g, which was much higher than the 1136.58 ng / g in the control group; the ratio (selenocysteine / methylselenocysteine) increased from 1.83 in the control group to 6.36, indicating that the proportion of oxidized diselenyl bonds (selenocysteine) increased significantly.

[0043] At low temperatures, Se-CDs significantly enhanced the accumulation of storage-type organic selenium (selenomethionine), which helps alleviate the inhibition of selenium accumulation caused by low temperatures and improves the nutritional quality of rice. The selenomethionine content under Se-CDs treatment was 251.99 ng / g, while the control was only 65.07 ng / g, an increase of nearly 3 times.

[0044] according to Figure 1 The metabolic pathway diagram shows that selenomethionine, selenocysteine, and methylselenocysteine ​​are different forms of organic selenium in the same pathway. Although they have different redox properties, they are all effective forms for the human body to absorb organic selenium from food.

[0045] Example 2 RR and 9311 were grown in pots. Foliar spraying with 5 mg / L Se-CDs, 5 mg / L Na2SeO3, and ddH2O was applied once each during the booting stage (ear differentiation stage III) and the heading stage (70% of plants heading). During the mid-grain filling stage (9 to 15 days after flowering), a temperature control treatment with a daily average temperature of 33℃ was implemented (simulating the natural high temperature during the mid-grain filling stage). Grains were collected 15 days after flowering, and the changes in the content of the main stress-resistance marker amino acids (selenocystine, Se-cystine, Cys-Se-Se-Cys) among the organic selenium species in the dehulled grains were measured and analyzed.

[0046] Table 3. Effects of Se-CDs treatment at high temperatures during grain filling on selenocysteine ​​content in rice grains.

[0047] According to Table 3, Se-CDs spraying can significantly increase the accumulation of stress-resistant selenocystine in grains of different rice varieties (including special red rice and conventional white rice), which is better than the traditional selenium fertilizer Na2SeO3 treatment. This indicates that carbon quantum dot Se-CDs significantly enhance the accumulation of stress-resistant organic selenium in different rice varieties.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. Application of selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains.

2. The application according to claim 1, characterized in that, The rice is colored rice and / or white rice.

3. The application according to claim 1, characterized in that, The organoselenium includes one or more of selenocysteine, methylselenocysteine, or selenomethionine.

4. The application according to claim 1, characterized in that, The selenium-containing carbon quantum dots are prepared by the following method: selenocysteine ​​hydrochloride and m-phenylenediamine are mixed in ultrapure water and reacted at 120-200℃ for 6-12 h under anaerobic conditions. After purification, a nanomaterial colloid containing selenium-containing carbon quantum dots is obtained; the mass ratio of selenocysteine ​​hydrochloride to m-phenylenediamine is 2-3:

1.

5. Application of selenium-containing carbon quantum dots in enhancing the accumulation of organic selenium in rice grains at high temperatures during the mid-grain-filling stage.

6. The application according to claim 5, characterized in that, The high temperature during the mid-grain filling stage refers to an average temperature of 33℃ or higher from 9 to 15 days after rice flowering.

7. The application according to claim 5, characterized in that, The organic selenium is selenomethionine.

8. Application of selenium-containing carbon quantum dots in enhancing the accumulation of selenocystine in rice grains at high temperatures during the mid-grain-filling stage.

9. A method for rice cultivation, characterized in that, This includes spraying selenium-containing carbon quantum dots once during the third stage of rice panicle differentiation and once on the day of heading.

10. The method according to claim 9, characterized in that, The application concentration of the selenium-containing carbon quantum dots is 1~10 mg / L.

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