Application of externally applied vitamin B2 in improving salt tolerance of wheat

Abstract

The invention discloses application of externally applied vitamin B2 to improvement of salt tolerance of wheat, and belongs to the technical field of agricultural planting. Under salt stress, wheat seed germination and seedling growth are obviously inhibited, the inhibition effect of salt stress on wheat seed germination and seedling growth is effectively relieved through reasonable external application of vitamin B2, and it is revealed that the wheat seed germination and seedling growth are obviously inhibited by increasing the relative water content and photosynthetic pigment content of wheat leaves under salt stress through exogenous vitamin B2. The invention provides an action mechanism for improving the salt tolerance of wheat through the ways of improving the salt tolerance of wheat, enhancing the activity of antioxidant enzymes such as SOD (superoxide dismutase), POD (peroxidase) and CAT (catalase), inhibiting active oxygen such as H2O2 and O2 <.-> and the generation of MDA (malondialdehyde), and the like, and provides a new thought for solving the problem of wheat production in soil salinization regions and improving the salt tolerance and salt tolerance breeding of wheat.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural planting, and in particular to an application of externally applied vitamin B2 in improving the salt tolerance of wheat. Background Art

[0002] Soil salinization is one of the most important abiotic factors affecting agricultural production and the ecological environment, and poses a serious threat to agricultural sustainable development and food security. The salt in salinized soil causes stress to plants through osmotic and ionic effects, causing physiological disorders in plants, thereby inhibiting plant seed germination and growth and development, leading to a significant reduction in crop yield and quality. Studies have shown that salt stress induces the production of a large amount of reactive oxygen species and Na+ in plant cells. + Excessive absorption destroys cell membrane structure, inhibits photosynthesis, interferes with material metabolism, and induces oxidative stress, osmotic stress, ionic stress, nutritional stress and other secondary stresses, resulting in plant growth stunting and even death. In recent years, with global climate change and industrial and agricultural development, the area of ​​natural salinization and artificial salinization has increased, resulting in huge economic losses in agricultural production. Therefore, soil salinization has become a major issue that urgently needs to be solved.

[0003] Wheat is an important food crop and one of the main crops cultivated on salinized land. Wheat grows relatively weakly during the seed germination and seedling growth period, has poor salt tolerance, and is more sensitive to salt stress. Therefore, improving wheat's salt tolerance and promoting wheat seed germination and seedling establishment are of great significance for ensuring wheat production in soil salinization areas and national food security.

[0004] Vitamin B2, also known as riboflavin, belongs to the water-soluble B vitamins. Vitamin B2 is a natural substance widely found in animals and plants, but its content varies greatly in different organisms or tissues. As a direct precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), vitamin B2 is essential for plant photosynthesis, respiration and redox metabolism. Studies have shown that exogenous application of vitamin B2 can improve the stress resistance of some plants, such as disease resistance, drought resistance and waterlogging resistance. However, whether vitamin B2 can improve the salt tolerance of wheat has not been reported. Summary of the invention

[0005] The inventors found that the rational application of exogenous vitamin B2 can effectively improve the salt tolerance of wheat, providing a new idea for solving the problem of wheat cultivation in soil salinization areas.

[0006] The technical solution of the present invention is as follows: The first aspect of the present invention provides the use of exogenous vitamin B2 in improving the salt tolerance of wheat.

[0007] Specifically, experimental data show that under salt stress, applying vitamin B2 to wheat has at least the following effects: i) Alleviate the inhibition of salt stress on wheat seed germination; ii) Alleviate the inhibition of salt stress on wheat growth.

[0008] Salt stress can significantly inhibit wheat seed germination and wheat growth, while exogenous application of vitamin B2 can effectively alleviate the inhibitory effects of salt stress on wheat seed germination and growth.

[0009] Furthermore, in the application of vitamin B2 to alleviate the inhibition of wheat growth by salt stress, vitamin B2 is specifically applied to the roots of wheat. Experiments have shown that vitamin B2 improves wheat salt tolerance by at least one of the following pathways: a) Enhance water retention in wheat cells under salt stress; b) Protect the integrity of wheat cell membranes under salt stress; c) Enhance the stability of photosynthetic pigments in wheat leaves under salt stress; d) reduce the accumulation of reactive oxygen species in wheat leaf cells under salt stress; e) Increase the activity of antioxidant enzymes in wheat leaves under salt stress.

[0010] A second aspect of the present invention provides a nutrient for preventing and treating salt stress in wheat, wherein vitamin B2 is one of the active ingredients.

[0011] Preferably, in the above-mentioned nutrient, the concentration of vitamin B2 is 8-20 μmol / L. Although the external application of vitamin B2 can effectively alleviate the inhibitory effect of salt stress on wheat germination and growth, the test results also show that the mitigation effect depends on the concentration of exogenous microorganism B2; for example, under the salt stress conditions of some embodiments of the present invention, the solution containing vitamin B2 has a better effect when the concentration is 8-20 μmol / L.

[0012] The third aspect of the present invention provides the use of the above-mentioned nutrient for preventing and controlling wheat salt stress in improving the growth condition of wheat under salt stress or enhancing the germination ability of wheat seeds under salt stress.

[0013] A fourth aspect of the present invention provides a method for improving the growth condition of wheat under salt stress, specifically comprising: applying exogenous vitamin B2 to the roots of wheat.

[0014] A fifth aspect of the present invention provides a method for improving the germination ability of wheat seeds under salt stress, specifically comprising: soaking the wheat seeds in a solution containing vitamin B2.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention has discovered for the first time the positive effect of exogenous vitamin B2 on the growth and development of wheat under salt stress, and has deeply studied the mechanism of action of vitamin B2 in alleviating wheat salt stress, providing a scheme for improving wheat salt tolerance by using exogenous vitamin B2, providing a technical reference for the application of vitamin B2 in wheat production practice in soil salinization areas, and providing a theoretical basis for seeking new ways to improve wheat salt resistance and salt-tolerant breeding. Compared with other soil salinization solutions, the present invention's solution to wheat salt tolerance using exogenous vitamin B2 has the advantages of low cost, easy operation, high safety and good effect, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings used in the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a comparison diagram of the growth status of wheat seedlings under different treatment conditions in Example 2 of the present invention; Figure 2 The dyeing method used in Example 3 of the present invention detects H2O2 (A) and O2 in wheat leaves under different treatment conditions. .- (B) Result diagram of accumulation. DETAILED DESCRIPTION

[0018] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which the present invention belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention; the terms "including" and "having" in the specification and claims of the present invention and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0020] Under salt stress conditions, wheat seed germination and seedling growth are significantly inhibited, resulting in delayed wheat growth and development. In order to solve the problem of wheat salt stress, the present invention provides a solution for improving wheat salt tolerance by applying vitamin B2 externally, achieving the technical effect of effectively alleviating the damage of salt stress to wheat and improving the ability of wheat to resist salt stress.

[0021] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0022] The wheat varieties used in the following examples are all Jimai 22, and the data processing method used is: SPSS 21.0 software is used for one-way analysis of variance, and the least significant difference method (LSD) is used for difference significance analysis (P<0.05). If no specific technology or conditions are specified in the examples, the technology or conditions described in the literature in this field or the product instructions are used. The reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially.

[0023] Example 1 Seed germination is a prerequisite for normal growth and development of wheat under salt stress. This example shows the effect of exogenous vitamin B2 on wheat seed germination under salt stress. The experimental process is as follows: After the wheat seeds were disinfected with 1% sodium hypochlorite solution, they were placed in sterile culture dishes lined with dry filter paper. 100 wheat seeds were placed in each dish. 5 mL of the corresponding treatment solution was added as shown in Table 1. Then they were cultured in a dark incubator at 25°C for 7 days, and the treatment solution was changed every 2 days. The germination standard was the cracking of the seed coat and the exposure of the radicle. The germination standard was the length of the embryo greater than or equal to half of the seed length. The germination of wheat seeds was counted from the second day of dark culture. Three replicates were set for each treatment.

[0024] Table 1 Experimental treatments

[0025] The results are shown in Table 2. Salt stress has a certain inhibitory effect on wheat seed germination. Compared with the CK group, the germination potential, germination rate and germination index of wheat seeds in the R0 group were significantly reduced by 36.67%, 31.06% and 34.47%, respectively. After applying different concentrations of exogenous vitamin B2, the germination potential of wheat seeds in the R5, R10 and R20 groups increased significantly by 7.60%, 32.16% and 11.11%, the germination rate increased significantly by 5.94%, 26.24% and 9.42%, and the germination index increased by 5.55%, 28.25% and 7.79%, respectively, compared with the R0 group. This shows that exogenous vitamin B2 can alleviate the inhibitory effect of salt stress on wheat seed germination, and the best alleviating effect is achieved with a concentration of 10 μmol / L vitamin B2.

[0026] Table 2 Effects of exogenous vitamin B2 on wheat seed germination under salt stress

[0027] Example 2 Growth status is a comprehensive reflection of wheat's response to salt stress. This example shows the effect of applying vitamin B2 on the growth of wheat seedlings under salt stress under hydroponic conditions. The experimental operation is as follows: Wheat seeds were disinfected with 1% sodium hypochlorite solution, placed in a sterile culture dish lined with moist filter paper, and cultured in a dark incubator at 25°C for 2 days. After the seeds turned white, the seedlings with uniform germination were selected and transplanted into a black hydroponic box containing 1L Hoagland nutrient solution. The seeds were then transferred to a light incubator (day / night temperature of 25°C / 18°C, light / dark cycle of 16 h / 8 h, light intensity of 100 μmol·m -2 ·s -1 , relative humidity of 75%) for 3 days, strong wheat seedlings with consistent growth were selected and divided into 5 groups. 1 L of corresponding treatment solution was added to each group as shown in Table 1, and then cultured in the light incubator for 10 days, during which the treatment solution was replaced every 2 days. After 10 days of treatment, the phenotype was observed and photographed, and mixed samples were taken within the treatment for the determination of various growth and physiological indicators. Each treatment was repeated 3 times. Among them, the seedling growth indicators were determined by using a ruler to measure the seedling height and root length of the wheat seedlings; using a balance to weigh the fresh weight and dry weight of the wheat seedlings; and using the scanning method to count the number of lateral roots of the wheat seedlings. The results are shown in the figure. Figure 1 And as shown in Table 3.

[0028] Table 3 Effects of exogenous vitamin B2 on the growth of wheat seedlings under salt stress

[0029] From the above results, it can be seen that the growth of wheat seedlings was inhibited to a certain extent under salt stress. Compared with the CK group, the seedling height, root length, fresh weight, dry weight and lateral root number of wheat seedlings in the R0 group were significantly reduced by 30.16%, 52.15%, 57.99%, 39.22% and 77.60%, respectively. The application of different concentrations of exogenous vitamin B2 showed different degrees of promotion on the growth of wheat seedlings under salt stress. The growth indicators of wheat seedlings showed a trend of first increasing and then decreasing with the increase of vitamin B2 concentration. Among them, the promotion effect of 10 μmol / L vitamin B2 was the most significant. The seedling height, root length, fresh weight, dry weight and lateral root number of wheat seedlings in the R10 group were significantly increased by 12.13%, 27.53%, 9.92%, 12.90% and 64.29% compared with the R0 group. The above results show that exogenous vitamin B2 can alleviate the inhibitory effect of salt stress on the growth of wheat seedlings, but the mitigation effect depends on the concentration of exogenous vitamin B2.

[0030] Example 3 Referring to the experimental operation in Example 2, wheat seedlings under different treatment conditions were obtained. This example further explored the regulatory pathways of vitamin B2 to improve wheat salt tolerance, including the following aspects: (1) Effects of exogenous application of vitamin B2 on the relative water content and relative electrical conductivity of wheat leaves under salt stress.

[0031] The relative water content of leaves is an important indicator for measuring the water retention of plant cells, and the relative conductivity of leaves is a basic indicator for testing the integrity of plant cell membranes. In this example, the relative water content of fresh wheat leaves was determined by the fresh weight method, and the relative conductivity of fresh wheat leaves was determined by the conductivity method. The test results are shown in Table 4.

[0032] Table 4 Detection results of relative water content and relative conductivity of wheat leaves under different treatment conditions

[0033] As shown in Table 4, the relative water content of wheat leaves under salt stress (R0 group) was significantly reduced by 10.62% compared with the CK group; after applying different concentrations of exogenous vitamin B2, the relative water content of wheat leaves in R10 and R20 groups was significantly increased by 7.43% and 9.58% respectively compared with the R0 group, but there was no significant difference between the R5 group and the R0 group; the relative conductivity of wheat leaves under salt stress (R0 group) was significantly increased, which was 1.6 times that of the CK group; after applying different concentrations of exogenous vitamin B2, the relative conductivity of wheat leaves in R5, R10 and R20 groups was significantly reduced by 10.46%, 26.58% and 20.42% compared with the R0 group. The above results show that exogenous vitamin B2 can not only enhance the water retention of wheat leaf cells under salt stress, but also protect the integrity of wheat leaf cell membranes under salt stress.

[0034] (2) Effect of exogenous application of vitamin B2 on the content of photosynthetic pigments in wheat leaves under salt stress.

[0035] The content of photosynthetic pigments in leaves is an important indicator of the photosynthetic capacity of plants. In this example, the ethanol extraction method was used to determine the light and pigment content of fresh wheat leaves in each group, and the test results are shown in Table 5.

[0036] Table 5 Detection results of photosynthetic pigment content in wheat leaves under different treatment conditions

[0037] As shown in Table 5: Salt stress caused a significant decrease in the content of photosynthetic pigments in wheat leaves. Compared with CK, the contents of chlorophyll a, chlorophyll b, carotenoids and total chlorophyll in wheat leaves of group R0 decreased by 16.84%, 16.18%, 19.66% and 16.64%, respectively. After applying different concentrations of exogenous vitamin B2, the content of photosynthetic pigments in wheat leaves under salt stress showed different degrees of increase. Compared with group R0, the chlorophyll a content of wheat leaves in groups R5, R10 and R20 increased by 7.68%, 20.89% and 14.86%, respectively, the chlorophyll b content increased by 0.25%, 9.02% and 16.29%, respectively, the carotenoid content increased by 10.14%, 18.53% and 15.38%, respectively, and the total chlorophyll content increased by 5.97%, 18.18% and 15.11%, respectively. The above results indicate that exogenous application of vitamin B2 can enhance the stability of photosynthetic pigments in wheat leaves under salt stress and promote photosynthesis.

[0038] (3) Effect of exogenous application of vitamin B2 on the content of reactive oxygen and malondialdehyde (MDA) in wheat leaves under salt stress.

[0039] The specific detection method is as follows: H2O2 tissue staining uses the diaminobenzidine method (DAB) and content determination uses the molybdate method (kit produced by Nanjing Jiancheng Bioengineering Research Institute); O2 .- Tissue staining was performed using the nitroblue tetrazolium (NBT) method, and content determination was performed using the hydroxylamine hydrochloride oxidation method (a kit produced by Beijing Solebow Technology Co., Ltd.); MDA content was determined using the thiobarbituric acid (TBA) method (a kit produced by Nanjing Jiancheng Bioengineering Institute). Figure 2 and as shown in Table 6.

[0040] Table 6 Detection results of active oxygen and malondialdehyde content in wheat leaves under different treatment conditions

[0041] from Figure 2 From Table 6, we can see that salt stress induces H2O2 and O2 .- Large accumulation, R0 group H2O2 and O2 .- The contents of H2O2 in the R10 and R20 groups were 1.75 and 2.65 times of those in the CK group, respectively, and the amount of MDA produced was 1.76 times of that in the CK group, indicating that excessive accumulation of reactive oxygen species in wheat leaf cells under salt stress caused cell membrane lipid peroxidation. After applying different concentrations of exogenous vitamin B2, the H2O2 content in the wheat leaves of the R10 and R20 groups was significantly reduced by 32.0% and 25.9% respectively compared with the R0 group, and O2 .- The contents of H2O2 and O2 in wheat leaves of R5 group were significantly reduced by 55.8% and 46.8%, and the contents of MDA were significantly reduced by 31.5% and 21.2%..- The content of MDA in the wheat leaf was not significantly different from that in the R0 group, but the content of MDA was significantly reduced by 8.9%. The above results show that the application of vitamin B2 can reduce the production of reactive oxygen and MDA in wheat leaf cells under salt stress and reduce the degree of peroxidation of wheat leaf cell membrane under salt stress.

[0042] (4) Effect of exogenous application of vitamin B2 on the activity of antioxidant enzymes in wheat leaves under salt stress.

[0043] The method for determining the activity of antioxidant enzymes is: using the hydroxylamine method to determine the activity of SOD, using the guaiacol method to determine the activity of POD, and using the ammonium molybdate method to determine the activity of CAT. The specific operation method refers to the instructions of the kit produced by Nanjing Jiancheng Bioengineering Research Institute. The test results are shown in Table 7.

[0044] Table 7 Detection results of antioxidant enzyme activities in wheat leaves under different treatment conditions

[0045] As shown in Table 7: Under salt stress, compared with the CK group, the SOD activity of wheat leaves in the R0 group increased significantly by 18.5%, and the POD and CAT activities decreased significantly by 12.8% and 34.5%, respectively; after applying different concentrations of exogenous vitamin B2, the activities of SOD, POD and CAT in wheat leaves under salt stress increased; compared with the R0 group, the SOD activity of wheat leaves in the R10 and R20 groups increased significantly by 57.4% and 43.4%, POD activity increased significantly by 26.7% and 13.0%, and CAT activity increased significantly by 60.8% and 51.3%, respectively; there was no significant difference in the POD and CAT activities of wheat leaves in the R5 group compared with the R0 group, but the SOD activity increased significantly by 17.8%. The above results show that exogenous vitamin B2 can increase the activity of antioxidant enzymes in wheat leaves under salt stress, thereby accelerating the removal of reactive oxygen species and reducing the oxidative damage caused by the accumulation of reactive oxygen species in cells.

[0046] In summary, under salt stress conditions, wheat seed germination and seedling growth were inhibited to a certain extent. Its seed germination indicators such as germination potential, germination rate and germination index, as well as seedling growth indicators such as seedling height, root length, fresh weight, dry weight and lateral root number were significantly lower than those under normal conditions. After applying different concentrations of exogenous vitamin B2, various indicators of wheat seed germination and seedling growth under salt stress showed different degrees of improvement, but the effect of vitamin B2 at concentrations of 5 μmol / L and 20 μmol / L was less than that of vitamin B2 at a concentration of 10 μmol / L, indicating that appropriate concentrations of vitamin B2 can alleviate the inhibitory effects of salt stress on wheat seed germination and seedling growth. Specifically, the exogenous application of appropriate concentrations of vitamin B2 can effectively alleviate the damage of salt stress to wheat seedlings and improve the salt tolerance of wheat through the following regulatory pathways: increase the water retention of wheat leaves under salt stress, increase the relative water content of leaves, and maintain the physiological functions of cells; inhibit the degradation of photosynthetic pigments in wheat leaves under salt stress, increase the content of photosynthetic pigments, and promote photosynthesis; enhance the activity of antioxidant enzymes such as SOD, POD and CAT, reduce the accumulation of reactive oxygen, reduce the level of membrane lipid peroxidation, protect the integrity of cell membranes, and reduce electrolyte extravasation.

[0047] It should be noted that the present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present invention are all included in the technical scope of the present invention. In addition, without departing from the scope of the main purpose of the present invention, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present invention.

Claims

1. Application of exogenous vitamin B2 in improving salt tolerance of wheat.

2. The use according to claim 1, characterized in that: Under salt stress, the vitamin B2 has at least the following uses: i) Alleviate the inhibition of salt stress on wheat seed germination; ii) Alleviate the inhibition of salt stress on wheat growth.

3. The use according to claim 2, characterized in that: The vitamin B2 is applied to the roots of wheat.

4. The use according to claim 2, characterized in that: The vitamin B2 improves the salt tolerance of wheat by at least one of the following ways: a) Enhance water retention in wheat cells under salt stress; b) Protect the integrity of wheat cell membranes under salt stress; c) Enhance the stability of photosynthetic pigments in wheat leaves under salt stress; d) reduce the accumulation of reactive oxygen species in wheat leaf cells under salt stress; e) Increase the activity of antioxidant enzymes in wheat leaves under salt stress.

5. A nutrient for preventing and treating salt stress in wheat, characterized in that: Vitamin B2 is one of the active ingredients.

6. The nutritional supplement according to claim 5, characterized in that The concentration of vitamin B2 is 8-20 μmol / L.

7. Use of the nutrient according to claim 5 or 6 in improving the growth condition of wheat under salt stress.

8. Use of the nutrient according to claim 5 or 6 in improving the germination ability of wheat seeds under salt stress.

9. A method for improving wheat growth under salt stress, characterized in that: Apply vitamin B2 to the wheat roots.

10. A method for improving the germination ability of wheat seeds under salt stress, characterized in that: Soak wheat seeds in a solution containing vitamin B2.

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