A composition for improving salt tolerance of plants and use thereof

Abstract

The present application belongs to the field of agricultural technology, and particularly relates to a composition for improving salt tolerance of plants and application thereof. The present application applies auxin (in the form of aqueous solution or powder), an aqueous solution of auxin and proline, an aqueous solution of auxin and betaine, an aqueous solution of auxin-proline-betaine ternary complex to plants by foliar spraying or root irrigation. Experiments have proved that auxin can quickly promote the sodium ion efflux of plants, reduce the sodium ion content in plants, and significantly improve the salt tolerance; the above-mentioned complex treatment can produce a synergistic effect, and further improve the growth of plants in a high-salt environment. The composition provided by the present application can be used as a plant salt tolerance promoter in field production, has a remarkable effect on enhancing the adaptability and stress resistance of plants to salt-affected land, has strong practicability, and has good popularization and application value.

Description

Technical Field

[0001] This invention belongs to the field of agricultural technology, specifically relating to a composition for improving the salt tolerance of plants and its application. Background Technology

[0002] Soil salinization is one of the major abiotic stresses limiting agricultural production. Saline-alkali land is widely distributed in my country, especially in coastal areas where large areas remain undeveloped. Researching the mechanisms of plant salt tolerance and developing simple and efficient technologies to improve plant salt tolerance is of significant practical importance and application value for expanding the effective utilization area of ​​arable land in my country, promoting sustainable agricultural development, and ensuring national food security.

[0003] Plant hormones play a crucial role in regulating plant growth, development, and stress response, and have been widely used in agricultural production. Among them, auxin, as a common plant hormone, has been extensively studied for its role in regulating plant growth. However, there are currently no clear research reports on the application of auxin and its compound systems with proline and betaine in improving plant salt tolerance, and mature, efficient application methods and related formulations are also lacking.

[0004] Existing technologies for improving plant salt tolerance suffer from problems such as complex operation, limited effectiveness, reliance on expensive reagents, and demanding storage conditions, making it difficult to meet the needs of large-scale field production. Therefore, developing a simple, efficient, and cost-effective application method and related formulation based on auxin to improve plant salt tolerance and solve the technical problem of insufficient salt tolerance in current saline-alkali land cultivation has become an urgent issue in the field of stress-resistant agricultural cultivation. This invention is proposed accordingly. Summary of the Invention

[0005] To address the problems of existing soil salinization limiting agricultural production, and the complexity, limited effectiveness, or reliance on expensive reagents in existing technologies for improving plant salt tolerance, this invention provides the application of auxin in improving plant salt tolerance, methods for improving plant salt tolerance using auxin and its compound system, and related formulations, filling the gap in existing technologies and meeting the needs of large-scale field production.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: On the one hand, the present invention provides a composition for improving the salt tolerance of plants, wherein the effective component of the composition is auxin; or the effective component is a combination of auxin and at least one of proline and betaine.

[0007] Furthermore, the concentration of the auxin used is 50 nM to 100 nM; the concentration of proline and betaine used is 5 mM to 20 mM.

[0008] Secondly, the present invention provides the application of the composition in improving the salt tolerance of plants.

[0009] Furthermore, the application involves improving the salt tolerance of plants by promoting the excretion of sodium ions from plants, reducing the sodium ion content in plants, or increasing the growth of plants in high-salt environments.

[0010] Furthermore, the composition is applied to the plants in the form of an aqueous solution.

[0011] Furthermore, the aqueous solution is applied by foliar spraying or root irrigation.

[0012] Thirdly, the present invention provides a method for improving the salt tolerance of plants using the composition, wherein an aqueous solution prepared from the composition is applied to plants by foliar spraying or root irrigation, thereby promoting the excretion of sodium ions from plants, reducing the sodium ion content in the plant, or increasing the growth of plants in high-salt environments, thus enhancing the salt tolerance of plants.

[0013] Furthermore, when the active ingredient of the composition is auxin, it enhances the salt tolerance of plants by promoting the efflux of sodium ions and reducing the sodium ion content in the plant.

[0014] Furthermore, when the effective component of the composition is a combination of auxin and proline, a combination of auxin and betaine, or a combination of auxin, proline, and betaine, the plant's salt tolerance is enhanced by increasing the plant's growth in a high-salt environment.

[0015] Fourthly, the present invention also provides a plant salt stress reliever, wherein the active ingredient of the salt stress reliever is the aforementioned composition, and the salt stress reliever is applied as a plant salt tolerance promoter in field production. Compared with the prior art, the beneficial effects and significant advantages of the present invention are as follows: 1. The method of applying exogenous auxin and its compound system adopted in this invention is simple to operate, cost-effective, and quick to take effect. It can effectively improve the growth of plants in high-salt environments and can be applied on a large scale in agricultural production in saline-alkali land. It is of great significance for expanding the effective utilization area of ​​arable land.

[0016] 2. This invention is the first to clearly demonstrate that auxin can rapidly promote the excretion of sodium ions from plants, reduce the sodium ion content in plants, and significantly improve the salt tolerance of plants; and it was found that when auxin is combined with proline and betaine, the salt tolerance effect can be further enhanced. Compared with the use of single reagents, the effect is better, and there is no need to rely on expensive reagents, making it highly practical.

[0017] 3. The formulation provided by this invention is reasonable, easy to prepare, and flexible in application. It is suitable for different crop cultivation scenarios, which can not only solve the problem of plant growth in saline-alkali land, but also promote sustainable agricultural development and ensure food security. It has extremely high promotion and application value. Attached Figure Description

[0018] Figure 1. Effects of exogenous auxin treatment on sodium ion efflux and sodium ion content in Arabidopsis thaliana; Figure 2 is a schematic diagram showing the changes in salt tolerance of auxin-synthetic mutants after exogenous auxin application. Figure 3. Schematic diagram of the regulatory effect of exogenous auxin on sodium ion efflux and sodium ion content in different crops; Figure 4. Schematic diagram of the synergistic promoting effect of auxin combined with proline or betaine on Arabidopsis growth under high salt stress. Figure 5. Schematic diagram of the synergistic effect of the combined treatment of auxin, proline and betaine on Arabidopsis growth under high salt stress. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Example 1: Effects of exogenous auxin treatment on sodium ion efflux and in vivo sodium ion content in Arabidopsis thaliana Seven-day-old wild-type (WT) Arabidopsis thaliana seedlings with consistent growth status were selected and grown for 24 h in 1 / 2 MS media, 100 mM NaCl, and 100 mM NaCl with a specified concentration of NAA (naphthaleneacetic acid, an auxin). Net Na+ in the roots was then measured using non-destructive microelectrode techniques. + Flow rate. Positive values ​​represent Na. + External discharge, negative values ​​represent Na + Internal flow. Then, WT seedlings that had grown for 7 days were grown in a liquid medium of 100 mM NaCl and 100 mM + 100 nM NAA for 24 h. After the liquid solution was poured off and the seedlings were allowed to stand for 3 h, the Na+ in their roots was... + The results of the content test.

[0021] The results are as follows Figure 1Figures A and B show the root tip Na content of Arabidopsis seedlings treated with 100 mM NaCl alone (salt stress group). + The efflux rate was significantly higher than that of the 1 / 2 MS control group, indicating that salt stress can induce Arabidopsis root cells to initiate Na+ efflux. + An efflux mechanism is used to resist salt stress damage; in the experimental group treated with NaCl plus NAA, as the NAA concentration increased, the Na+ efflux in the seedling root tips decreased. + The efflux rate showed a significant increasing trend, with the root tip Na of the seedlings in the 100 nM NAA treatment group showing the highest rate. + The efflux capacity was increased by 935% compared to the NaCl treatment alone. These results confirm that under salt stress, exogenous application of auxin can significantly enhance the NaCl excretion capacity of Arabidopsis root cells. + It has excellent excretion capacity, and its effect is particularly significant at appropriate concentrations.

[0022] like Figure 1 As shown in Figure C: Compared with the NaCl-treated group alone, the experimental group with exogenous application of 100 nM NAA had reduced NaCl content in the roots of Arabidopsis thaliana. + The significantly reduced content indicates that exogenous auxin treatment can effectively reduce the accumulation of sodium ions in Arabidopsis thaliana under salt stress, further supporting the evidence that auxin can improve the salt tolerance of Arabidopsis thaliana by promoting sodium ion efflux and reducing the sodium ion content in the body.

[0023] Example 2: Salt-sensitive phenotype of auxin synthesis mutant and the mitigating effect of exogenous auxin For WT, which has grown for 4 days wei8-1 , wei8-2;tar2-1 , yuc8;yuc9 , yucQ ( yuc3;yuc5;yuc7; yuc8;yuc9 The structural changes in root tips observed by confocal microscopy (PI staining) after treatment with 150 mM NaCl medium for 24 h, 48 h, and 72 h. WT plants that had grown for 4 days were... wei8-1 , yuc8;yuc9 , yucQ Root length phenotype of seedlings after 5 days of growth in 1 / 2 MS medium containing 150 mM NaCl and 150 mM NaCl + 50 nM NAA.

[0024] like Figure 2 As shown in Figure A, mutants synthesized from various auxins at 4 days of age ( wei8-1 , wei8-2;tar2-1 , yuc8;9 , yucQWhen auxin-synthetic mutants were treated together with WT Arabidopsis seedlings in a medium containing 150 mM NaCl, the degree of damage to the root tip structure of each mutant gradually increased compared with WT Arabidopsis as the salt stress time increased (24 h→48 h→72 h), and the root tip morphological distortion was more significant. This indicates that insufficient auxin synthesis leads to greater sensitivity of plants to salt stress, and salt stress causes more severe damage to their root tip tissues.

[0025] like Figure 2 As shown in Figures B and C, the root elongation phenotypic results of seedlings in the salt stress group (NaCl) and the relief group (NaCl + NAA) showed that under salt stress alone, the root elongation rate of each auxin synthesis mutant was significantly lower than that of WT Arabidopsis, indicating that auxin synthesis defects would exacerbate the inhibitory effect of salt stress on plant root elongation. However, the exogenous addition of 50 nM NAA not only significantly improved the root elongation rate of WT Arabidopsis under salt stress, but also effectively compensated for the root elongation defects of each auxin synthesis mutant, resulting in a significant increase in their root elongation rate.

[0026] The above experimental results confirm that insufficient auxin synthesis leads to a significant salt-sensitive phenotype in plants. Salt stress severely damages the root tip structure and inhibits root elongation. However, exogenous application of auxin (NAA) can effectively alleviate the damage to plant root tip tissue caused by salt stress, relieve the inhibitory effect of salt stress on root elongation, and significantly improve the salt tolerance of plants, further verifying the key role of auxin in the regulation of plant salt tolerance.

[0027] Example 3: The regulatory effect of exogenous auxin on sodium ion efflux and sodium ion content in different crops Verify that exogenous auxin promotes plant Na+ + Excretion and reduction of Na in plants + Whether the cumulative regulatory effect is species-wide, taking rapeseed as an example. Brassica napus Zhongshuang 11), soybeans ( Glycine max Williams 82), Corn ( Zea mays W22) and wheat ( Triticum aestivum Using four common crops as research subjects, this study provides experimental evidence for the widespread application of auxin as a salt tolerance promoter in the field.

[0028] like Figure 3 As shown in Figure AH, the Na content in the root tips of four crops... + The efflux rate detection results showed that, compared with the 100 mM NaCl treatment group alone, the root tip Na+ of rapeseed, soybean, corn, and wheat in the 1 μM NAA treatment group was significantly reduced. +The exogenous auxin capacity was significantly improved in all crops, with specific increases for each crop: corn 704.1%, wheat 452.2%, rapeseed 797.3%, and soybean 339.1%. This clearly demonstrates that exogenous auxins can effectively promote Na+ excretion in different crops. + It is discharged externally, and the improvement effect is significant.

[0029] To further investigate the effects of exogenous auxin on Na+ in crops + The cumulative effects were dynamically monitored using wheat and corn as examples, and the results are as follows: Figure 3 Figures I and J show the results: After wheat and maize seedlings treated with different methods were transferred to a standard hydroponic solution, the Na+ levels in the wheat and maize seedlings treated with NAA increased. + The NaCl content was consistently lower than that of the corresponding individual NaCl treatment group; and with the extension of transfer time (from 1 h to 3 h), the NaCl content between the two groups decreased. + The significantly increased difference in content indicates that exogenous auxin can sustainably inhibit the production of Na+ in wheat and corn. + The accumulation of auxin further confirms that auxin promotes the absorption of Na+. + Excretion and reduction of sodium in the body + Accumulation and its mechanism of action in regulating plant salt tolerance.

[0030] The above experimental results collectively confirm that exogenous auxin promotes Na+ production. + Excretion and reduction of Na in plants + The cumulative regulatory effect is not limited to a single species; it can be stably manifested in crops of different families and genera, such as corn, wheat, rapeseed, and soybean. This further confirms the species universality of this regulatory function and provides solid experimental support for the widespread application of auxin in the saline-alkali soil cultivation of various crops and the improvement of crop salt tolerance.

[0031] Example 4: Synergistic effect of auxin combined with proline or betaine on Arabidopsis growth under high salt stress To investigate the synergistic effect of auxin and osmotic regulators on plant salt tolerance response, this example combines auxin with proline and auxin with betaine, respectively, and treats Arabidopsis seedlings under high salt stress conditions. The relevant growth indicators of the plants are observed and statistically analyzed to clarify the effect of the combination treatment on improving the salt tolerance of the plants.

[0032] As shown in Figure 4, Arabidopsis seedlings that had grown for 4 days were selected and transferred to 1 / 2 MS medium containing 150 mM NaCl. Treatment groups included 150 mM NaCl alone, NaCl + 50 nM NAA, NaCl + 10 mM Pro (proline), and a combination of NaCl + 50 nM NAA + 10 mM Pro. After 10 days of culture, growth indicators such as the number of lateral roots, root length, root fresh weight, and aboveground fresh weight were measured. The results showed that compared with the 150 mM NaCl treatment group alone, the growth indicators of the NaCl + 50 nM NAA group and the NaCl + 10 mM Pro group were significantly improved. The combined treatment of NAA and proline (NaCl + 50 nM NAA + 10 mM Pro group) had a more significant promoting effect on plant growth, with a significant increase in the number of lateral roots, root length, root fresh weight and aboveground fresh weight. Among them, the aboveground fresh weight and root fresh weight were almost close to the level of 1 / 2 MS normal culture group.

[0033] like Figure 4 As shown in Figure FJ, four additional treatment groups were established: a 150 mM NaCl single treatment group, a NaCl + 50 nM NAA treatment group, a NaCl + 10 mM Betaine treatment group, and a NaCl + 50 nM NAA + 10 mM Betaine combined treatment group. These groups were cultured under 150 mM NaCl stress for 10 days, and the measured indicators were consistent with the previous experiments. The results showed that the growth-promoting trend of the auxin + betaine combined treatment on Arabidopsis thaliana was basically consistent with that of the auxin + proline combined treatment. All growth indicators of the combined treatment group were significantly better than those of the NaCl single treatment group.

[0034] The above results indicate that auxin can reduce sodium ion accumulation and alleviate sodium ion toxicity, while proline or betaine can improve osmotic balance and alleviate osmotic stress. The two have a significant synergistic effect in improving plant salt tolerance, jointly enhancing Arabidopsis' tolerance to high salt stress and significantly increasing plant growth under salt stress.

[0035] Example 5: Synergistic effect of combined treatment with auxin, proline and betaine on Arabidopsis growth under high salt stress To investigate the synergistic effect of auxin combined with proline and betaine in plant salt tolerance response, this study set up multiple treatment groups under two high salt stress conditions of 100 mM NaCl and 150 mM NaCl, and measured relevant growth indicators of Arabidopsis thaliana to clarify the effect of the combination of the three substances in improving plant salt tolerance.

[0036] like Figure 5As shown in Figure AF, Arabidopsis thaliana seedlings that had grown for 4 days were transferred to 1 / 2 MS medium containing 100 mM NaCl or 150 mM NaCl, respectively. Treatment groups included NaCl alone, NaCl + 50 nM NAA, NaCl + 10 mM Pro / Betaine (proline or betaine), NaCl + 50 nM NAA + 10 mM Pro / Betaine, and a combination of NaCl + 50 nM NAA + 10 mM Pro + 10 mM Betaine. After 10 days of culture, growth indicators such as the number of lateral roots, root fresh weight, and aboveground fresh weight were recorded. The results showed that all growth indicators in the NaCl + NAA + Pro / Betaine and NaCl + NAA + Pro + Betaine groups were significantly better than those in the NaCl alone stress control group. Among them, the combination treatment group of auxin, proline and betaine had the most significant effect on promoting plant growth, and the number of lateral roots, root fresh weight and aboveground fresh weight were close to or significantly higher than those of the salt-free normal culture control group.

[0037] The above results indicate that the combined treatment of auxin, proline and betaine can produce a stronger synergistic effect, which can jointly improve the tolerance of Arabidopsis to high salt stress from multiple aspects such as alleviating sodium ion toxicity and improving osmotic stress, and significantly promote the growth of plants under salt stress.

Claims

1. A composition for improving the salt tolerance of plants, characterized in that, The active ingredient of the composition is auxin; or the active ingredient is a combination of auxin and at least one of proline and betaine.

2. The composition according to claim 1, characterized in that, The concentration of the auxin used is 50 nM to 100 nM; the concentration of proline and betaine used is 5 mM to 20 mM.

3. The use of the composition according to claim 1 or 2 in improving the salt tolerance of plants.

4. The application according to claim 2, characterized in that, The application aims to enhance the salt tolerance of plants by promoting the excretion of sodium ions, reducing the sodium ion content in the plant, or increasing the growth of plants in high-salt environments.

5. The application according to claim 2, characterized in that, The composition is applied to plants in the form of an aqueous solution.

6. The application according to claim 4, characterized in that, The aqueous solution is applied by foliar spraying or root irrigation.

7. A method for improving the salt tolerance of plants using the composition according to claim 1 or 2, characterized in that, An aqueous solution prepared from the composition is applied to plants by foliar spraying or root irrigation. This promotes the excretion of sodium ions from the plant, reduces the sodium ion content in the plant, or increases the growth of plants in high-salt environments, thereby enhancing the plant's salt tolerance.

8. The method according to claim 6, characterized in that, When the active ingredient of the composition is auxin, it enhances the salt tolerance of plants by promoting the efflux of sodium ions and reducing the sodium ion content in the plant.

9. The method according to claim 6, characterized in that, When the active ingredient of the composition is a combination of auxin and proline, a combination of auxin and betaine, or a combination of auxin, proline, and betaine, the salt tolerance of plants is improved by increasing the growth of plants in high-salt environments.

10. A plant salt stress reliever, characterized in that, The active ingredient of the salt stress reliever is the composition described in claim 1 or 2, and the salt stress reliever is used as a plant salt tolerance promoter in field production.

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