Saline-alkali soil seed germination and growth promoter based on 3-hydroxydecanoic acid as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of agricultural biology, and particularly relates to a saline-alkali soil seed germination and growth promoter based on 3-hydroxydecanoic acid as well as a preparation method and application thereof. The accelerant consists of the following components in percentage by weight: 2-10% of a mixture of 3-hydroxydecanoic acid and 3-hydroxydecanoic acid dipolyester, 1-5% of hydroxypropyl-beta-cyclodextrin, 1-5% of mineral source potassium fulvate, 0.1-1% of polyether, and the balance of water, wherein the pH is regulated to 6.5 + / -0.1 by potassium hydroxide. The 3-hydroxydecanoic acid dipolyester is prepared by carrying out self-condensation esterification on 3-hydroxydecanoic acid in the presence of a strong acid catalyst. The accelerant is prepared by sequentially dissolving all the components and adjusting the pH value, and can be applied to seed dressing and coating or drip irrigation and dilution during use. Experimental results show that the accelerator can significantly improve the seed germination rate, the seedling root length, the fresh weight and the chlorophyll content of wheat, corn, cotton and rape in saline-alkali soil with the salt content of 0.2-1.0%, so that the early growth performance of crops in a saline-alkali environment is effectively enhanced.

Description

Technical Field

[0001] This invention belongs to the field of agricultural biotechnology, specifically relating to a seed germination and growth promoter based on 3-hydroxydecanoic acid in saline-alkali soil, its preparation method, and its application. Background Technology

[0002] Saline-alkali land is widely distributed in Northwest and North my country. Its soil has high soluble salt content and alkaline pH, often accompanied by osmotic stress, ion toxicity, and nutrient imbalance, severely restricting crop seed germination and seedling growth. When soil salinity reaches 0.3% or higher, most grain and cash crops experience decreased germination rates, hindered root development, reduced seedling biomass, and lower leaf chlorophyll content, significantly impacting yield. Existing saline-alkali land improvement technologies, such as salt drainage and leaching, application of organic fertilizers or soil conditioners, and introduction of salt-tolerant varieties, while improving the salt-stress environment to some extent, suffer from slow effectiveness, large dosage requirements, high costs, or limited applicability.

[0003] In seed treatment and growth promotion, amino acids, humic acid, seaweed polysaccharides, and microbial agents are currently used to alleviate saline-alkali stress. However, these methods are generally affected by poor stability of active ingredients, limited effectiveness in high-salt environments, or poor adaptability to different crops, making it difficult to fully meet the needs of high-efficiency agricultural production in saline-alkali land. Among these, mineral-derived fulvic acid is the most widely used in saline-alkali land improvement, as it has a long-lasting effect in improving soil structure and microbial communities, but its rapid effectiveness is limited.

[0004] Hydroxy fatty acids are a class of naturally sourced substances with biocompatibility and surface activity. However, there are no publicly reported applications of hydroxy fatty acids in promoting germination and early growth of crops in saline-alkali soils. Therefore, developing a compound growth promoter that can effectively promote seed germination, enhance seedling root development, and improve aboveground growth performance in saline-alkali environments is of great significance for improving agricultural productivity in saline-alkali lands. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of low seed germination rate, limited root growth of seedlings, and slow aboveground growth in existing saline-alkali land crops, especially the insufficient effectiveness of conventional growth promoters or improvement measures under saline-alkali soil conditions. This invention provides a 3-hydroxydecanoic acid-based seed germination and growth promoter for saline-alkali land, its preparation method, and its application. This promoter can significantly improve the early growth performance of crops under saline-alkali conditions.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a seed germination and growth promoter for saline-alkali soil based on 3-hydroxydecanoic acid. The promoter comprises, by weight percentage: 2-10% mixture of 3-hydroxydecanoic acid and 3-hydroxydecanoic acid diester; 1-5% hydroxypropyl-β-cyclodextrin; 1-5% potassium humate (mineral source); 0.1-0.5% polyether; appropriate amount of potassium hydroxide aqueous solution with a mass concentration of 10%-25% (for adjusting pH to 6.5±0.1); the balance is water.

[0007] Furthermore, the structural formula of the 3-hydroxydecanoic acid diepolyester is shown below: .

[0008] Secondly, the present invention provides a method for preparing the above-mentioned accelerator, specifically comprising: dissolving a mixture of 3-hydroxydecanoic acid and 3-hydroxydecanoic acid diester, hydroxypropyl-β-cyclodextrin, potassium humate, and polyether in water in a mass percentage ratio of 2~10:1~5:1~5:0.1~0.5, and adding potassium hydroxide with a mass concentration of 10%~25% to adjust the pH to 6.5±0.1, and then adding water to make up the volume.

[0009] Furthermore, the 3-hydroxydecanoic acid diester is obtained by self-condensation esterification of 3-hydroxydecanoic acid at 100°C in the presence of a strong acid catalyst (such as sulfuric acid). The water generated during the reaction is removed by heating and vaporization to obtain a mixture in the target proportion. The accelerator is prepared by sequentially dissolving each component, adjusting the pH to 6.5, and adding water to the specified content, followed by stirring and filtration to remove insoluble matter.

[0010] Furthermore, the strong acid catalyst is preferably concentrated sulfuric acid with a mass concentration of 1-3% of 3-hydroxydecanoic acid.

[0011] Thirdly, the present invention provides an application of the aforementioned promoter in enhancing the early growth performance of crops in saline-alkali environments.

[0012] Furthermore, the promoter of the present invention can be used for: (1) seed coating treatment: the promoter is uniformly coated at a rate of 1 to 10 mL per kilogram of seeds; (2) drip irrigation application: the promoter is diluted 1,000 to 10,000 times and applied to the soil with water.

[0013] Furthermore, the application can significantly improve the germination rate of wheat, corn, cotton and rapeseed seeds and the root length, fresh weight or chlorophyll content of seedlings under saline-alkali soil conditions with a salt content of 0.2% to 1.0%.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1) This invention is the first to apply 3-hydroxydecanoic acid and its diester to promote early growth of crops in saline-alkali soil. No reports in the published literature have described the use of 3-hydroxydecanoic acid or its diester to improve germination and seedling growth in crops under salt stress. This invention utilizes its stress-resistance properties to significantly improve seed germination and seedling growth conditions. 2) The compound system exhibits a significant synergistic effect. The cyclodextrin coating slows down the degradation and loss of 3-hydroxydecanoic acid in the environment, providing a slow-release effect; the diester can be degraded into monomeric 3-hydroxydecanoic acid by lipases in the soil, also providing a slow-release effect; the addition of potassium humate improves soil buffering capacity and promotes root development; and the polyether enhances the osmotic desalination effect. The synergistic effect of the components significantly improves crop growth indicators under typical saline-alkali soil conditions with a salt content of 0.2%–1.0%. 3) This invention can significantly improve the seed germination rate, seedling root length, seedling fresh weight, and chlorophyll content of crops such as wheat, corn, cotton, and rapeseed, indicating that the promoter is stable and effective for a variety of crops. Furthermore, the preparation method is simple, the conditions are mild, and it is easy to industrialize. The core raw materials are obtained through a controllable esterification reaction, and the promoter uses water as the main solvent. The process allows for large-scale application.

[0015] 4) In addition, this growth promoter is flexible in its application methods and adaptable to different agricultural scenarios. It is suitable for seed coating, drip irrigation, or other fertigation methods, and is not limited by soil conditions or crop types, making it easy to promote on a large scale in saline-alkali areas. Attached Figure Description

[0016] Figure 1 The HPLC chromatograms of 3-hydroxydecanoic acid and 3-hydroxydecanoic acid diester are shown. Figure 2 The images show the results of the corn seedling emergence experiment in pots. After 14 days of cultivation, three corn seedlings were randomly selected from each group. Figure 3 The images show the results of a wheat seedling emergence experiment in the field. After 14 days of cultivation, wheat samples were taken from each group, and 10 plants were randomly selected for photography. Groups 1-6 were, in order, normal soil, saline soil + 5 mL / kg seed accelerator, saline soil + 10 mL / kg seed accelerator, saline soil + 5000 times diluted seed accelerator, and saline soil + 10 mL / kg seed accelerator according to the comparative formula. Figure 4 Soil column diagrams are shown for 15 hours and 99 hours after drip irrigation. 1-3 represent the water group, the accelerator group diluted 5000 times, and the accelerator group diluted 10000 times, respectively. Detailed Implementation

[0017] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following embodiments are only for illustrating the present invention and should not be regarded as limiting the scope of the present invention.

[0018] The 3-hydroxydecanoic acid (CAS: 5561-87-5) and polyether 1307 used in the examples are commercially available products from BASF. All other compounds are conventional commercially available products. Unless otherwise specified, conditions in the examples were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used in the examples, unless otherwise specified by the manufacturer, are all commercially available products.

[0019] Example 1: Preparation of a mixture of 3-hydroxydecanoic acid and 3-hydroxydecanoic acid diester Take a 250 mL three-necked flask equipped with a mechanical stirrer, thermometer, and a water separator (or short-path distillation head), and add 100.0 g of 3-hydroxydecanoic acid (purity ≥98%). Add 2.0 g of concentrated sulfuric acid (2.0 wt% of the mass of 3-hydroxydecanoic acid) as a strong acid catalyst at room temperature, start stirring (about 300 rpm), and slowly raise the temperature. When the system temperature reaches 100 °C, maintain the temperature for 1.0 h. Water generated during the reaction will vaporize with heating and be continuously removed by the water separator, collecting approximately 0.8–1.2 mL of water. After the reaction is complete, stop heating and allow the system to cool naturally to about 60 °C. Slowly add 5 wt% sodium bicarbonate aqueous solution to the reaction solution to neutralize to pH≈5, allow to stand and separate the layers, and discard the aqueous phase. Remove residual water and trace volatiles from the organic phase under reduced pressure at 60 °C and −0.08 MPa to obtain 97.5 g of a colorless to pale yellow transparent viscous liquid product.

[0020] HPLC analysis revealed the product to be a mixture of 3-hydroxydecanoic acid and its diester, with the diester comprising approximately 45 wt% of 3-hydroxydecanoic acid, and the remainder consisting of unreacted 3-hydroxydecanoic acid and a small amount of polyester (≤3 wt%). The resulting mixture can be directly used in subsequent reactions or formulations. The HPLC chromatogram is shown below. Figure 1 As shown.

[0021] Example 2: Preparation of 1000 mL of accelerator Five groups of accelerators with the same composition but different mass ratios were prepared. The specific formulations of each group are shown in Table 1. The mixture of 3-hydroxydecanoic acid and 3-hydroxydecanoic acid diester was prepared by the method described in Example 1.

[0022] Table 1. Preparation of 1000 mL of accelerator

[0023] Preparation steps: Take 600 mL of deionized water and add it to a stirrer; add 3-hydroxydecanoic acid / dipolyester mixture, hydroxypropyl-β-cyclodextrin, potassium humate and polyether in sequence until completely dissolved; adjust the pH to 6.5 with 10% potassium hydroxide solution; add water to 1000 mL; the resulting promoter is a slightly viscous homogeneous liquid.

[0024] Example 3: Industrial production of 1000 L accelerator The concentrations and masses of each component in the industrial production of the 1000 L accelerator are shown in Table 2.

[0025] Table 2 Industrial production of 1000 L accelerator

[0026] Process flow: Configure 600 L soft water; 70 kg of 3-hydroxydecanoic acid / dipolyester mixture was added to an industrial mixer at 300 rpm. Hydroxypropyl-β-cyclodextrin, potassium humate, and polyether were added sequentially. Adjust the pH to 6.5 ± 0.1 by adding 25% KOH solution. Add water to 1000 L; After filling and sealing, approximately 1000 L of product is obtained. This process method is suitable for scale-up of 1–20 tons / batch.

[0027] Example 4: Germination Experiment of Wheat in Greenhouse Pots Materials: Yangmai 27 wheat variety with plump grains and a purity of ≥98%; Saline soil: 0.7% salt content, pH 8.5, loam (source: coastal soil from Yancheng, Jiangsu). Planting method: Sow 10 seeds per pot, 3 pots per group; Greenhouse conditions: 25℃±2℃, light intensity 14 h / d; Method of using the accelerator: As in Example 3, for seed dressing: the amount of accelerator is 5 mL or 10 mL per kg of seeds. Control: Seeds mixed with water (normal soil); Comparative example: without 3-hydroxydecanoic acid and diester, the content of other substances is the same as the formulation in Example 3, 10 mL / kg for seed mixing.

[0028] On the 14th day after sowing, the parameters of wheat plants in each group were measured, and the results are shown in Table 3.

[0029] Table 3 Comparison of parameters for each group on day 14 after sowing.

[0030] Note: Different values ​​for a and e indicate a statistically significant difference between groups greater than 0.05. It is evident that saline soil with a salt content of 0.7% significantly inhibited wheat germination and seedling growth. Seed treatment with a growth accelerator significantly improved wheat germination rate, seedling growth, and chlorophyll content, indicating that the growth accelerator has a good effect in resisting salt stress. While the control group without 3-hydroxydecanoic acid also had some effect, the effect was poor, suggesting that 3-hydroxydecanoic acid and its dimer play a key role in the growth accelerator formulation.

[0031] Example 5: Germination Experiment of Corn in Greenhouse Pots Materials: Corn variety Aoyu 503; Saline soil: 0.7% salt content, sandy loam (source: Gansu); Planting method: Sow 6 seeds per pot, 4 pots per group; Greenhouse conditions: 25℃±2℃, light intensity 14 h / d; Instructions for using the accelerator: After preparing the formula in Example 3, dilute the accelerator 5000 times or 10000 times as seedling water, using 50 mL per pot.

[0032] Control: 50 mL of water for seedling emergence, followed by treatment with clean water (normal soil); Comparative example: without 3-hydroxydecanoic acid and diester, the content of other substances is the same as the formulation of Example 3, and it is used in the germination water, diluted 5000 times, with 50 mL of germination water per pot.

[0033] On the 14th day after sowing, the parameters of the maize plants in each group were measured, and the results are shown in Table 4.

[0034] Table 4 Comparison of parameters for each group on day 14 after sowing

[0035] Note: Different values ​​for a and e indicate a statistically significant difference between groups greater than 0.05. It is evident that saline soil with a salt content of 0.7% significantly inhibited corn germination and seedling growth, and corn exhibited slightly lower salt tolerance than wheat. Treatment with a seedling growth promoter as part of the emergence water significantly improved corn germination rate, seedling growth, and chlorophyll content, indicating that the promoter has a good effect against salt stress. While the control group without 3-hydroxydecanoic acid also showed some effect, the result was weaker, suggesting that 3-hydroxydecanoic acid and its dimer play a crucial role in the promoter formulation. The morphology of corn seedlings in each group after 14 days is shown below. Figure 2 As shown.

[0036] Example 6: Germination Experiment of Rapeseed Potted Plants in Greenhouse Ingredients: Rapeseed variety Zheshuang 72; Saline soil: 0.65% salt content, pH 8.44, loam (source: coastal soil from Wenling, Zhejiang). Planting method: Sow 15 seeds per pot, 3 pots per group; Greenhouse conditions: 25℃±2℃, light intensity 14 h / d; Method of using the accelerator: For the formulation in Example 3, seed dressing: the amount of accelerator is 5 mL or 10 mL per kg of seeds; Control: Seeds mixed with water (normal soil); Comparative example: without 3-hydroxydecanoic acid and diester, the content of other substances is the same as the formulation in Example 3, 10 mL / kg for seed mixing.

[0037] On the 14th day after sowing, the parameters of the rapeseed plants in each group were measured, and the results are shown in Table 5.

[0038] Table 5 Comparison of parameters for each group on day 14 after sowing.

[0039] Note: Different values ​​for a–e indicate a significant difference between groups greater than 0.05.

[0040] It is evident that saline soil with a salt content of 0.65% significantly inhibited rapeseed germination and seedling growth, with all indicators significantly lower than those in normal soil treatment. After seed treatment with the promoter from Example 3, the germination rate, root length, plant height, seedling fresh weight, and SPAD value of rapeseed were all improved to varying degrees, with the 10 mL / kg treatment showing the best effect. Most indicators approached or recovered to the levels of normal soil, indicating that the promoter has a good salt stress resistance effect on rapeseed. In contrast, the comparative formulation without 3-hydroxydecanoic acid and its dimer, although it could alleviate salt damage to some extent, had a significantly weaker overall effect, further demonstrating that 3-hydroxydecanoic acid and its dimer play a key role in improving the salt resistance of rapeseed in the promoter formulation.

[0041] Example 7: Wheat Field Trial Crop: Yangmai 27, a wheat variety with plump grains and a purity of ≥98%; Promoter: Formula in Example 3, Seed dressing amount: 5 mL or 10 mL per kg of seeds, or diluted 5000 times as seed dressing. Comparative formulation: without 3-hydroxydecanoic acid and diester, the remaining components and contents are the same as in Example 3, and the seed dressing amount is 10 mL / kg; Location: Hangzhou, Zhejiang Province; Sowing date: November 1, 2025; Normal soil: Local non-saline loam soil, pH 7.2–7.5, salt content <0.2%; Saline soil: Secondary saline loam soil was selected from the field, with a salt content of about 0.7% and a pH of 8.4 to 8.6; Design: Randomized block trial; Community area: 10 m² 2 .

[0042] Processing settings (6 processes in total, 3 parallel cells per process): Normal soil (seed dressing with water); saline soil (seed dressing with water); saline soil + 5 mL / kg accelerator for seed dressing; saline soil + 10 mL / kg accelerator for seed dressing; saline soil + accelerator diluted 5000 times; saline soil + 10 mL / kg comparative formula for seed dressing; Sowing method: Sow in rows according to the local standard wheat density. Before sowing, treat the seeds evenly with appropriate treatment, dry them, and sow immediately. Field management: Except for different soil salinity treatment, other fertilizer, water and pest and weed control shall be carried out in accordance with local conventional high-yield cultivation methods.

[0043] 14 days after sowing: Investigate the basic seedling density (plants / m²) in each treatment plot. 2 ), and samples were taken to determine the fresh weight of the aboveground parts (g / m³). 2 ); 28 days after sowing: the fresh weight of the aboveground parts was measured again (g / m³). 2 Each plot has two fixed quadrats (0.5 m × 1 m), converted to g / m³. 2 The results are shown in Table 6.

[0044] Table 6. Field Trial Results

[0045] Note: Different lowercase letters (a–d) after the data in the same column indicate that the differences between treatments reached a significant level (P<0.05). Overall, the field trials validated the results of the pot experiments: under saline soil conditions of approximately 0.7%, seed treatment with the germination promoter from Example 3, especially at a dosage of 10 mL / kg, significantly improved wheat germination rate and seedling biomass in the field, demonstrating good potential for widespread application in wheat production on saline-alkali land. Furthermore, the promoter also achieved good results when used as an irrigation solution for emergence, with effects comparable to seed treatment at 10 mL / kg. Typical morphology of wheat seedlings sampled from the field after 14 days is shown below. Figure 3 As shown.

[0046] Example 8: Maize Field Trial Crop: Corn variety "Sweet Nuo 99", with plump kernels and a purity of ≥98%; Promoter: The formula in Example 3 is diluted 5000 times or 10000 times in the field under the same conditions as potted plants and used as seedling water; Comparative formulation: Contains no 3-hydroxydecanoic acid or its diester; all other components and contents are the same as in Example 3; diluted 5000 times and used as seedling water. Location: A slightly saline farmland in Hangzhou, Zhejiang Province; Sowing time: September 1, 2024.

[0047] Normal soil: Local non-saline sandy loam soil with a salt content of <0.2% and a pH of 7.0–7.5; Saline soil: Secondary saline sandy loam soil was selected from the same plot, with a salt content of about 0.7% and a pH of 8.2 to 8.5; Design: Randomized block trial; Community area: 10 m² 2 .

[0048] Processing settings (5 processes in total, 3 parallel cells per process): Normal soil (100 mL of water for seedling emergence per planting hole); Saline soil (treated with 100 mL of water used for seedling emergence); Saline soil + water diluted 5000 times with a seedling accelerator, with a water supply of 100 mL per hole; Use saline soil and a seedling accelerator diluted 10,000 times for watering, and supply water in the same way as above; Use saline soil + a 5000-fold diluted formula for seedling preparation, and supply water in the same way as above; Sowing method: Sow in holes, with 2 seeds per hole, row spacing 30 cm and plant spacing 20 cm; Field management: Except for differences in soil salinity and seedling water treatment, all other fertilizer and water management, as well as pest and weed control, are carried out in accordance with local high-yield maize cultivation techniques. 14 days after sowing: Investigate the germination rate (%) of each treatment plot, and measure the fresh weight of the aboveground parts (g / m²). 2 ); 28 days after sowing: Take another sample to determine the fresh weight of the aboveground parts (g / m²). 2 The results are shown in Table 7.

[0049] Table 7. Results of field experiments

[0050] Note: Different lowercase letters (a–d) after the data in the same column indicate that the differences between treatments reached a significant level (P<0.05).

[0051] Compared with normal soil, the germination rate of saline soil treated with water decreased by nearly half after 14 days; the fresh weight of the upper part of the plant was significantly reduced at 14 and 28 days. This indicates that saline soil with a salt content of about 0.7% has seriously affected the uniformity of corn emergence and seedling growth under field conditions, which is consistent with the results of pot experiments, further demonstrating that corn is sensitive to salt stress.

[0052] Under saline soil conditions, treatment with a 5000-fold diluted growth promoter not only facilitated seedling emergence but also promoted aboveground growth throughout the seedling stage. The improvement effect of a 10000-fold diluted growth promoter was slightly lower than that of the 5000-fold diluted promoter, but still significantly better than the saline soil-water treatment, and the 28-day fresh weight was significantly higher than the saline soil-water control. While the germination rate and fresh weight of the saline soil + control group were slightly higher than those of the saline soil-water treatment, both were significantly lower than those of the two concentrations of growth promoter.

[0053] Example 9: Cotton Field Trial Crop: Xinluzhong 83, with plump grains and a purity of ≥98%; Promoter: The formulation in Example 3, diluted 5000 times or 10000 times in the field, is applied as seedling emergence water with the drip irrigation system; Comparative formulation: Free of 3-hydroxydecanoic acid and its diester, with the remaining components and contents the same as in Example 3, diluted 5000 times and applied with drip irrigation; Location: A cotton field with slight salinization in Aksu City, Xinjiang; Sowing method: row sowing; Application method for seedling emergence irrigation: Apply seedling emergence irrigation water quantitatively along the sowing row through drip irrigation tape. Immediately after sowing, apply the irrigation water once, dissolving the growth promoter or comparison agent in the irrigation water. One month later, apply the irrigation water again, using the same treatment method as the first irrigation.

[0054] Normal soil: Local non-saline cotton field loam, with a salt content of <0.2% and a pH of approximately 7.2–7.5; Saline soil: Soil from cotton fields selected within the same farm, with a salt content of approximately 1.0% and a pH of approximately 8.5–8.7; Design: Randomized block trial; Community area: 10 m² 2 .

[0055] Processing settings (5 processes in total, 3 parallel cells per process): Normal soil (drip irrigation with clean water); saline soil (drip irrigation with clean water); saline soil + drip irrigation with a 5000-fold diluted accelerator; Saline soil + drip irrigation with a 10,000-fold diluted accelerator; saline soil + drip irrigation with a comparative formula diluted 5,000 times.

[0056] Sowing method: row sowing. Set the row spacing and sowing rate according to the local cotton conventional density. Before sowing, prepare the seedling water according to different treatments for the dry seeds. After sowing, apply the irrigation water equivalent to the seedling water in one go through the drip irrigation tape, so that the pesticide solution is concentrated near the sowing strip.

[0057] 28 days after sowing: Investigate the number of seedlings in each treatment plot; take samples to determine the fresh weight of the aboveground parts (g / m²). 2 ); Two months after sowing: the fresh weight of the aboveground parts was measured again (g / m²). 2 The results are shown in Table 8.

[0058] Table 8. Field Experiment Test Results

[0059] Note: Different lowercase letters (a–d) after the data in the same column indicate that the differences between treatments reached a significant level (P<0.05).

[0060] In summary, under saline conditions in Aksu City, Xinjiang, drip irrigation with the seedling accelerator formulation from Example 3 significantly improved the germination rate and early fresh weight of cotton variety Xinluzhong 83, and markedly alleviated salt stress damage. In contrast, the comparative formulation without 3-hydroxydecanoic acid and its dimer showed a weaker effect, further demonstrating that 3-hydroxydecanoic acid and its dimer play a crucial role in improving crop salt resistance in accelerator formulations.

[0061] Example 10: Salt elution experiment on a soil column Salt-elution column experiments were conducted using high-salt clay from Aksu, Xinjiang. The clay was sieved through a 2 mm sieve and then loaded into... Figure 4 The acrylic columns shown were approximately 75 cm high. Each column was drip-irrigated for 15 hours, with a total water volume of 550 ml. Afterward, the soil was allowed to stand for 99 hours to reach saline equilibrium. Samples were taken from the soil layer at depths of 10-50 cm, and the total dissolved solids (TDS) were determined using a gravimetric method (referencing "Analysis of Water-Soluble Salts in Forest Soils" LY / T 1251-1999) to investigate the salt elution capacity of the accelerator. The results are shown in Table 9.

[0062] Table 9. Results of TDS content determination at different depths of saline soil columns.

[0063] It is evident that, compared to water, the eluting agent can wash salts into deeper soil layers, thereby reducing the surface soil salt content during seedling germination. This is one of the reasons why it promotes germination and seedling growth. Its salt-washing effect is related to the surface activity of hydroxydecanoic acid itself, as well as the excellent elution ability of the polyether contained in the formula.

[0064] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A 3-hydroxydecanoic acid based salt-affected soil seed germination and growth promoting agent, characterized by, The accelerator is composed of the following components in percentage by weight: 3-hydroxydecanoic acid and 3-hydroxydecanoic acid dimer mixture 2-10%, hydroxypropyl-β-cyclodextrin 1-5%, potassium fulvic acid 1-5%, polyether 0.1-0.5%; and the pH of the solution is adjusted to 6.5±0.1 by a potassium hydroxide aqueous solution with a mass concentration of 10-25%, and the balance is water.

2. The accelerator according to claim 1, characterized in that, The structural formula of the 3-hydroxydecanoic acid dimer is as follows: 。 3. A method of preparing the accelerator of claim 1, wherein, The method specifically comprises: sequentially dissolving 3-hydroxydecanoic acid and 3-hydroxydecanoic acid dimer mixture, hydroxypropyl-β-cyclodextrin, potassium fulvic acid, and polyether in water in percentage by mass: 2-10: 1-5: 1-5: 0.1-0.5, and adding a potassium hydroxide aqueous solution with a mass concentration of 10-25% to adjust the pH to 6.5±0.1, and adding water to constant volume.

4. The production method according to claim 3, characterized by, The preparation method of the 3-hydroxydecanoic acid and 3-hydroxydecanoic acid dimer mixture specifically comprises: taking 3-hydroxydecanoic acid as a raw material, heating to 100℃ in the presence of concentrated sulfuric acid with a mass concentration of 1-3% of 3-hydroxydecanoic acid, and then constant temperature stirring for 0.5-2 hours to make part of the 3-hydroxydecanoic acid undergo self-condensation esterification reaction to generate 3-hydroxydecanoic acid dimer.

5. Use of the accelerator according to claims 1-4 in enhancing the early growth performance of crops in saline-alkali environment.

6. Use according to claim 5, characterized in that, The specific mode of application is seed dressing, coating or drip irrigation dilution.

7. Use according to claim 6, characterized in that, When the seed dressing is applied, the use amount of the accelerator is 1-10 mL per kilogram of seeds.

8. Use according to claim 6, characterized in that, When the drip irrigation is applied, the accelerator needs to be diluted 1000-10000 times with water.

9. Use according to claim 6, characterized in that, The application can significantly improve the seed germination rate and seedling root length, fresh weight or chlorophyll content of wheat, corn, cotton and rape under the condition of saline-alkali soil with a salt content of 0.2%-1.0%. The structural formula of the 3-hydroxydecanoic acid dimer is as follows: The method specifically comprises: sequentially dissolving 3-hydroxydecanoic acid and 3-hydroxydecanoic acid dimer mixture, hydroxypropyl-β-cyclodextrin, potassium fulvic acid, and polyether in water in percentage by mass: 2-10: 1-5: 1-5: 0.1-0.5, and adding a potassium hydroxide aqueous solution with a mass concentration of 10-25% to adjust the pH to 6.5±0.1, and adding water to constant volume. The preparation method of the 3-hydroxydecanoic acid and 3-hydroxydecanoic acid dimer mixture specifically comprises: taking 3-hydroxydecanoic acid as a raw material, heating to 100℃ in the presence of concentrated sulfuric acid with a mass concentration of 1-3% of 3-hydroxydecanoic acid, and then constant temperature stirring for 0.5-2 hours to make part of the 3-hydroxydecanoic acid undergo self-condensation esterification reaction to generate 3-hydroxydecanoic acid dimer.

5. Use of the accelerator according to claims 1-4 in enhancing the early growth performance of crops in saline-alkali environment. The specific mode of application is seed dressing, coating or drip irrigation dilution. When the seed dressing is applied, the use amount of the accelerator is 1-10 mL per kilogram of seeds. When the drip irrigation is applied, the accelerator needs to be diluted 1000-10000 times with water. The application can significantly improve the seed germination rate and seedling root length, fresh weight or chlorophyll content of wheat, corn, cotton and rape under the condition of saline-alkali soil with a salt content of 0.2%-1.0%.

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