An abscisic acid and betaine co-crystal having high light stability and drought resistance and a preparation method thereof

Abstract

The application belongs to the technical field of pharmaceutical cocrystals, and provides a preparation method of abscisic acid and betaine cocrystals with high light stability and drought resistance, comprising the following steps: mixing abscisic acid, betaine and an organic solvent to obtain a mixed solution; evaporating and crystallizing the mixed solution to obtain the abscisic acid and betaine cocrystals. The application selects natural plant alkaloid betaine as a ligand, has good safety, and compared with synthetic chemicals, the natural ligand is generally less toxic to the environment and organisms, thereby reducing potential harm to the ecosystem. The abscisic acid-betaine cocrystals significantly improve the solubility of abscisic acid, and exhibit significant stability under light conditions. In addition, the cocrystals effectively improve the drought resistance of plants, thereby verifying the potential of the cocrystals as plant growth regulators. The research provides an effective strategy for improving the effectiveness of the plant growth regulator abscisic acid, and has a positive significance for reducing costs and environmental safety.

Description

Technical Field

[0001] This invention relates to the field of pharmaceutical cocrystallization technology, and in particular to a cocrystallization of abscisic acid and betaine with high photostability and drought resistance, and a method for preparing the same. Background Technology

[0002] Abscisic acid, chemical formula C 15 H 20 O4, with a relative molecular mass of 264.321, has the chemical name (S)-5-(1-hydroxy-4-oxo-2,6,6-trimethyl-2-cyclohexen-1-yl)-3-methyl-(2Z,4E)-pentadienoic acid, and its structural formula is shown below. It is poorly soluble in water at room temperature but readily soluble in methanol, ethanol, acetone, chloroform, ethyl acetate, and chloroform.

[0003]

[0004] Abscisic acid (ABA) is an important plant hormone widely distributed in plants, playing a crucial role, especially in responding to environmental stress and regulating growth and development. ABA is a secondary metabolite belonging to the terpenoid class of compounds. Its chemical structure consists of a cyclic ring and a long-chain fatty acid moiety, primarily synthesized by chloroplasts and other organelles within plants. Its synthesis typically involves the metabolic conversion of carotenoids, with a significant increase in synthesis, particularly during photosynthesis and in response to drought. ABA plays a key role in plant responses to stresses such as drought and salinity. It promotes stomatal closure, thereby reducing water evaporation; it also plays a vital role in seed development and dormancy, inhibiting seed germination and ensuring germination under suitable environmental conditions. Exogenous ABA is commonly used as an effective plant growth regulator, but it is photosensitive, with a half-life of only 24 minutes, and rapidly degrades into other products under strong light, significantly reducing its efficacy. Therefore, a method to improve the stability of ABA is needed. Thus, it is necessary to invent a new solid form to increase the stability of ABA and enhance its effectiveness. Summary of the Invention

[0005] The purpose of this invention is to provide a co-crystal of abscisic acid and betaine with high photostability and drought resistance, and its preparation method, so as to overcome the problems in the prior art of lacking the application of co-crystal strategies for abscisic acid in terms of photostability and drought resistance, and the need to improve photostability.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for preparing abscisic acid and betaine co-crystals with high photostability and drought resistance, comprising the following steps:

[0008] (1) Mix abscisic acid, betaine and organic solvent to obtain a mixed solution;

[0009] (2) Evaporate the mixed solution to obtain the abscisic acid and betaine co-crystal.

[0010] Preferably, the molar ratio of abscisic acid to betaine in step (1) is 4:1 to 20:1.

[0011] Preferably, the molar ratio of abscisic acid to organic solvent in step (1) is 1:1400 to 1:2700.

[0012] Preferably, the organic solvent in step (1) is one or more of methanol, ethanol, acetonitrile, ethyl acetate and acetone.

[0013] Preferably, the mixing temperature in step (1) is 25-30°C.

[0014] Preferably, the evaporation and crystallization temperature in step (2) is 25-30°C, and the evaporation and crystallization time is 30-35 hours.

[0015] Preferably, the crystal habit of the abscisic acid and betaine eutectic in step (2) is needle-shaped.

[0016] The present invention also provides a method for preparing the abscisic acid and betaine co-crystal with high photostability and drought resistance as described above.

[0017] This invention also provides the application of abscisic acid and betaine cocrystals with high photostability and drought resistance in plant growth regulators.

[0018] The present invention has the following beneficial effects:

[0019] (1) This invention uses betaine, a natural plant alkaloid, as a ligand, which has good safety. Compared with synthetic chemicals, natural ligands are generally less toxic to the environment and organisms, reducing potential harm to ecosystems. Since betaine is naturally present in plants and is often used for plant growth and protection, its application as a ligand enhances the biocompatibility of the co-crystal, ensuring healthy plant growth. Betaine not only enhances plant stress resistance but also has antioxidant and anti-inflammatory properties, which are of great significance in improving overall plant health and resisting environmental stress. The natural and harmless ligand betaine provides additional safety and eco-friendly advantages for the synthesis of the co-crystal, making it more feasible and sustainable in agricultural applications. This characteristic further enhances the application prospects of this invention and meets the needs of modern agriculture for environmentally friendly materials.

[0020] (2) The solubility of the eutectic disclosed in this invention is significantly higher than that of abscisic acid. This increased solubility not only facilitates the packaging, transportation and use of the formulation, but also means that plants can absorb abscisic acid more effectively, thereby rapidly exerting its biological activity.

[0021] (3) The eutectic disclosed in this invention significantly improves the stability of abscisic acid under ultraviolet light irradiation, thereby reducing the photodegradation of abscisic acid. This means that when applied under sunlight, the effectiveness of abscisic acid is maintained, and plants can benefit from its regulatory effects for a longer period of time. The improved photostability can reduce the frequency of abscisic acid application, thereby reducing costs and labor intensity, while also reducing potential environmental impacts.

[0022] (4) The co-crystals disclosed in this invention enhance the drought resistance of plants. This enhanced drought resistance may result from the synergistic effect of multiple mechanisms, including stomatal regulation, root development, osmotic pressure regulation, enhanced antioxidant capacity, and regulation of gene expression. These mechanisms work together to enable plants to better adapt to arid environments, thus providing an effective solution for agricultural production in the context of global climate change. Attached Figure Description

[0023] Figure 1 X-ray powder diffraction patterns of abscisic acid, betaine, and the abscisic acid-betaine eutectic of Example 1;

[0024] Figure 2 The experimental X-ray powder diffraction pattern of the abscisic acid-betaine eutectic in Example 1 and the powder diffraction pattern calculated from the eutectic single crystal data are shown below.

[0025] Figure 3 The following are the DSC and TGA analysis results of the abscisic acid-betaine eutectic from Example 1;

[0026] Figure 4 This is a microscopic image of the abscisic acid-betaine eutectic crystal from Example 1.

[0027] Figure 5 This is a standard curve of abscisic acid content in the photostability test of the abscisic acid-betaine eutectic crystal in Example 1;

[0028] Figure 6 Degradation diagrams of abscisic acid, a physical mixture of abscisic acid and betaine, and the abscisic acid-betaine eutectic from Example 1;

[0029] Figure 7 Phenotypic changes in plants treated with abscisic acid, a physical mixture of abscisic acid and betaine, and the abscisic acid-betaine cocrystal of Example 1;

[0030] Figure 8Graph showing the reduction in fresh weight of aboveground parts of plants treated with abscisic acid, a physical mixture of abscisic acid and betaine, and the abscisic acid-betaine eutectic of Example 1;

[0031] Figure 9 The X-ray powder diffraction patterns are for the products of Examples 1-3 and Comparative Example 1. Detailed Implementation

[0032] This invention provides a method for preparing abscisic acid and betaine co-crystals with high photostability and drought resistance, comprising the following steps:

[0033] (1) Mix abscisic acid, betaine and organic solvent to obtain a mixed solution;

[0034] (2) Evaporate the mixed solution to obtain the abscisic acid and betaine co-crystal.

[0035] In this invention, the molar ratio of abscisic acid and betaine in step (1) is preferably 4:1 to 20:1, more preferably 6:1 to 18:1, and even more preferably 8:1 to 16:1.

[0036] In this invention, the molar ratio of abscisic acid to organic solvent in step (1) is preferably 1:1400 to 1:2700, more preferably 1:1600 to 1:2500, and even more preferably 1:1800 to 1:2300.

[0037] In this invention, the organic solvent in step (1) is preferably one or more of methanol, ethanol, acetonitrile, ethyl acetate and acetone.

[0038] In this invention, the mixing temperature in step (1) is preferably 25-30°C, more preferably 26-29°C, and even more preferably 27-28°C.

[0039] In this invention, step (1) requires mixing and stirring until the solid powder dissolves to obtain a mixed solution.

[0040] In this invention, the mixed solution in step (1) needs to be filtered first, and then transferred to a beaker covered with a perforated sealing film for evaporation and crystallization.

[0041] In this invention, the pore size of the filter membrane is preferably 0.20-0.25 μm, more preferably 0.21-0.24 μm, and even more preferably 0.22-0.23 μm.

[0042] In this invention, the evaporation and crystallization temperature in step (2) is preferably 25-30°C, more preferably 26-29°C, and even more preferably 27-28°C.

[0043] In this invention, the evaporation and crystallization time is preferably 30-35 hours, more preferably 31-34 hours, and even more preferably 32-33 hours.

[0044] In this invention, the crystal habit of the abscisic acid and betaine eutectic in step (2) is preferably needle-shaped.

[0045] The present invention also provides a method for preparing abscisic acid and betaine co-crystal with high photostability and drought resistance.

[0046] This invention also provides an application of abscisic acid and betaine co-crystal with high photostability and drought resistance in plant growth regulators.

[0047] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1

[0049] Accurately weigh 100 mg of abscisic acid and betaine in a molar ratio of 4:1 into a crystallizer using an electronic balance. Add 15 ml of ethanol and mix and stir at 30 °C for 2 h until the solid powder is completely dissolved. Then filter (filter membrane pore size is 0.22 μm). Transfer the filtrate to a beaker covered with a perforated sealing membrane and evaporate and crystallize at 30 °C. After 30 h, high-quality abscisic acid-betaine eutectic needle crystals are obtained.

[0050] Abscisic acid, betaine, and the abscisic acid-betaine eutectic obtained in this embodiment were analyzed by X-ray diffraction. Figure 1 As shown.

[0051] Then, the experimental X-ray powder diffraction pattern of the abscisic acid-betaine eutectic obtained in the examples was compared with the powder diffraction pattern calculated from the eutectic single crystal data, such as... Figure 2 As shown.

[0052] from Figure 1As can be seen from the data, the X-ray powder diffraction pattern of the product obtained in this embodiment is within the range of diffraction angles 2θ = 5.82±0.2°, 10.45±0.2°, 11.58±0.2°, 12.66±0.2°, 13.39±0.2°, 14.30±0.2°, 15.04±0.2°, 15.39±0.2°, 16.29±0.2°, 17.42±0.2°, 17.68±0.2°, 19.19±0.2°, 20.10±0.2°, 20.36±0.2°, 22.00±0.2°, 23.30±0.2°, 23.87±0.2°, 24 Diffraction peaks were observed at 0.21±0.2°, 24.82±0.2°, 25.47±0.2°, 25.73±0.2°, 27.50±0.2°, 29.01±0.2°, 30.53±0.2°, and 33.90±0.2°. Characteristic peaks were observed at 2θ = 5.82±0.2°, 10.45±0.2°, 11.58±0.2°, 12.66±0.2°, 13.39±0.2°, 14.30±0.2°, 17.42±0.2°, 17.68±0.2°, 19.19±0.2°, 24.82±0.2°, and 25.47±0.2°. These characteristic peaks differed from those of abscisic acid and betaine, indicating the formation of a eutectic.

[0053] from Figure 2 As can be seen from the experimental X-ray powder diffraction pattern of the abscisic acid-betaine eutectic in Example 1, and the powder diffraction pattern calculated from the eutectic single crystal data, the results are consistent with those obtained from the simulation. Figure 1 This consistency indicates the accuracy of the X-ray powder diffraction experiment.

[0054] The abscisic acid-betaine eutectic obtained in this embodiment was subjected to thermal analysis. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were performed on a TGA / DSC1 (Mettler-Toledo, Switzerland) under a nitrogen atmosphere. 5–10 mg of sample was placed in a crucible and then heated from 273.15 K to 673.15 K at a rate of 10 K / min under pure nitrogen atmosphere. The results are as follows: Figure 3 As shown.

[0055] from Figure 3 As can be seen from the figure, the melting point of the abscisic acid-betaine eutectic obtained in this embodiment is 144.15℃.

[0056] Figure 4 The images shown are of the product appearance in this embodiment. Figure 4 As can be seen from the results, the abscisic acid-betaine eutectic product obtained in this embodiment has a white needle-like appearance, and its solubility in water at 25°C increased by 102.54%.

[0057] The photostability of the abscisic acid-betaine eutectic obtained in this embodiment was tested as follows: Three saturated aqueous solutions of abscisic acid, abscisic acid-betaine eutectic, and a physical mixture of abscisic acid and betaine were prepared. Each of the three solutions was transferred to a quartz test tube wrapped in aluminum foil and subjected to darkness. All test tubes were then exposed to a light source consisting of a 300W high-pressure mercury lamp equipped with a 365nm ultraviolet filter for 22 hours. Samples were taken at specified time intervals and centrifuged for 3 minutes. The supernatant was analyzed by HPLC (Agilent 1200, Agilent Technologies, Inc., USA). The standard curve for abscisic acid content is shown below. Figure 5 As shown. All experiments were repeated three times, and the results are as follows. Figure 6 As shown.

[0058] from Figure 5 and Figure 6 As can be seen, after 2 hours of UV irradiation, both abscisic acid and the physical mixture of abscisic acid and betaine degraded by nearly 60%, while the abscisic acid-betaine eutectic remained intact, retaining 91.48%. The degradation of the physical mixture of abscisic acid and betaine was similar to that of abscisic acid, indicating that the synthesized eutectic exhibits unique interactions in both solid and liquid forms, demonstrating a significant advantage over simple physical mixtures. After 22 hours of UV irradiation, the abscisic acid-betaine eutectic continued to exhibit superior photostability, with a residual rate of 92.18%, while the other formulations largely degraded.

[0059] The drought resistance of the abscisic acid-betaine cocrystal obtained in this embodiment was evaluated using the following method: Wheat seeds were vernalized and then sown in a growth medium composed of vermiculite and soil in a 1:1 (V / V) ratio, with a 1 cm layer of soil covering the seeds. After two weeks of normal watering, the control group was watered with 50 ml of water daily. Conversely, other groups received different treatments under drought conditions: daily spraying with 10 ml of abscisic acid, abscisic acid-betaine cocrystal, a physical mixture of abscisic acid and betaine, and pure drought treatment. All plant treatment groups were kept under light conditions, and each treatment was repeated three times. Five days later, phenotypic changes in the plants were observed, and the fresh weight reduction (FWR) of the aboveground parts was recorded based on the following equation.

[0060]

[0061] Phenotypic changes in plants, such as Figure 7 As shown.

[0062] from Figure 7As can be seen, under pure drought conditions, the plants exhibited obvious wilting, with leaves turning yellow, curling, and narrowing. Under drought conditions, the effects of spraying abscisic acid and a saturated solution of abscisic acid-betaine physical mixture on plant growth were similar. Notably, the plants treated with abscisic acid-betaine cocrystal maintained the most upright posture, and their phenotypic characteristics were very similar to those of plants under normal irrigation conditions, indicating that abscisic acid-betaine cocrystal possesses excellent photostability and drought resistance.

[0063] Further quantification of the fresh weight reduction (FWR) of the aboveground parts, such as... Figure 8 As shown.

[0064] from Figure 8 As can be seen from this, the results are consistent with... Figure 7 The phenotypic changes observed were consistent. Under pure drought conditions, plants reduced the growth of their aboveground parts to minimize water loss through transpiration, resulting in a significant reduction in leaf area and consequently, a decrease in fresh weight. Compared with other treatments, the plant fresh weight reduction rate (4.45%) was significantly lowest in the abscisic acid-betaine co-crystal treatment. This indicates that the abscisic acid-betaine co-crystal effectively improved the drought resistance of plants.

[0065] Example 2

[0066] Accurately weigh 100 mg of abscisic acid and betaine in a molar ratio of 12:1 into a crystallizer using an electronic balance. Add 15 ml of ethanol and mix and stir at 30 °C for 2 h until the solid powder is completely dissolved. Then filter (filter membrane pore size is 0.22 μm). Transfer the filtrate to a beaker covered with a perforated sealing membrane and evaporate and crystallize at 30 °C. After 35 h, high-quality abscisic acid-betaine eutectic needle crystals are obtained.

[0067] The abscisic acid-betaine eucrystalline crystal obtained in this embodiment was examined by X-ray diffraction. Figure 9 As shown.

[0068] from Figure 9As can be seen, the X-ray powder diffraction pattern of the product is at diffraction angles 2θ = 5.80±0.2°, 10.43±0.2°, 11.56±0.2°, 12.64±0.2°, 13.37±0.2°, 14.31±0.2°, 15.04±0.2°, 15.35±0.2°, 16.27±0.2°, 17.43±0.2°, 17.68±0.2°, 19.17±0.2°, 20.10±0.2°, 20.36±0.2°, 22.01±0.2°, 23.30±0.2°, 23.87±0.2°, and 24.21. Diffraction peaks are observed at ±0.2°, 24.83±0.2°, 25.49±0.2°, 25.71±0.2°, 27.50±0.2°, 29.01±0.2°, 30.53±0.2°, and 33.91±0.2°. Characteristic peaks are found at 2θ = 5.80±0.2°, 10.43±0.2°, 11.56±0.2°, 12.64±0.2°, 13.37±0.2°, 14.31±0.2°, 17.43±0.2°, 17.68±0.2°, 19.17±0.2°, 24.83±0.2°, and 25.49±0.2°. These characteristic peaks differ from those of abscisic acid and betaine, indicating the formation of a eutectic.

[0069] DSC results showed that its melting point was 143.68℃, the product had a white needle-like appearance, and its solubility in water at 25℃ increased by 100.16%.

[0070] The abscisic acid-betaine eutectic needle-like crystals obtained in this embodiment were subjected to photostability testing according to the method in Example 1. After 22 hours of ultraviolet irradiation, the abscisic acid-betaine eutectic crystals continued to exhibit superior photostability with a residual rate of 90.10%, while most of the other formulations degraded.

[0071] The abscisic acid-betaine eutectic needle-like crystals obtained in this example were evaluated for drought resistance according to the method in Example 1. Under drought conditions, the plants treated with the abscisic acid-betaine eutectic crystals remained the most robust, and their phenotypic characteristics were very similar to those of plants under normal irrigation conditions, indicating that the abscisic acid-betaine eutectic crystals possess excellent drought resistance. The fresh weight reduction rate of plants treated with the abscisic acid-betaine eutectic crystals (4.98%) was significantly lower than that of other treatments.

[0072] Example 3

[0073] Accurately weigh 100 mg of abscisic acid and betaine in a molar ratio of 20:1 into a crystallizer using an electronic balance. Add 15 ml of ethanol and mix and stir at 30 °C for 2 h until the solid powder is completely dissolved. Then filter (filter membrane pore size is 0.22 μm). Transfer the filtrate to a beaker covered with a perforated sealing membrane and evaporate and crystallize at 30 °C. After 32 h, high-quality abscisic acid-betaine eutectic needle crystals are obtained.

[0074] The abscisic acid-betaine eucrystalline crystal obtained in this embodiment was examined by X-ray diffraction. Figure 9 As shown.

[0075] from Figure 9 The X-ray powder diffraction pattern of the product can be seen at diffraction angles 2θ = 5.84±0.2°, 10.44±0.2°, 11.57±0.2°, 12.65±0.2°, 13.37±0.2°, 14.32±0.2°, 15.07±0.2°, 15.37±0.2°, 16.28±0.2°, 17.45±0.2°, 17.69±0.2°, 19.18±0.2°, 20.11±0.2°, 20.37±0.2°, 22.02±0.2°, 23.30±0.2°, 23.87±0.2°, and 24.22± Diffraction peaks were observed at 0.2°, 24.85±0.2°, 25.50±0.2°, 25.72±0.2°, 27.51±0.2°, 29.02±0.2°, 30.54±0.2°, and 33.92±0.2°. Characteristic peaks were observed at 2θ = 5.84±0.2°, 10.44±0.2°, 11.57±0.2°, 12.65±0.2°, 13.37±0.2°, 14.32±0.2°, 17.45±0.2°, 17.69±0.2°, 19.18±0.2°, 24.85±0.2°, and 25.50±0.2°. These characteristic peaks differed from those of abscisic acid and betaine, indicating the formation of a eutectic.

[0076] DSC results showed that its melting point was 144.04℃, the product had a white needle-like appearance, and its solubility in water at 25℃ increased by 98.67%.

[0077] The abscisic acid-betaine eutectic needle-like crystals obtained in this embodiment were subjected to photostability testing according to the method in Example 1. After 22 hours of ultraviolet irradiation, the abscisic acid-betaine eutectic crystals continued to exhibit superior photostability with a residual rate of 91.06%, while most of the other formulations degraded.

[0078] The abscisic acid-betaine eutectic needle-like crystals obtained in this example were evaluated for drought resistance according to the method in Example 1. Under drought conditions, the plants treated with the abscisic acid-betaine eutectic crystals remained the most robust, and their phenotypic characteristics were very similar to those of plants under normal irrigation conditions, indicating that the abscisic acid-betaine eutectic crystals possess excellent drought resistance. The fresh weight reduction rate of plants treated with the abscisic acid-betaine eutectic crystals (5.12%) was significantly lower than that of other treatments.

[0079] Comparative Example

[0080] Accurately weigh 100 mg of abscisic acid and betaine in a molar ratio of 1:3 into a crystallizer using an electronic balance. Add 15 ml of acetone and mix and stir at 30 °C for 2 h until the solid powder is completely dissolved. Then filter (filter membrane pore size is 0.22 μm). Transfer the filtrate to a beaker covered with a perforated sealing membrane and evaporate and crystallize at 30 °C. After a period of time, only a single component is obtained.

[0081] The X-ray powder diffraction pattern obtained in this comparative example is as follows: Figure 9 As shown.

[0082] In summary, the abscisic acid-betaine co-crystal significantly improved the solubility of abscisic acid and exhibited remarkable stability under light conditions. Furthermore, this co-crystal effectively enhanced plant drought resistance, validating its potential as a plant growth regulator. This study provides an effective strategy for improving the efficacy of the plant growth regulator abscisic acid, which has positive implications for cost reduction and environmental safety.

[0083] As shown in the above embodiments, this invention provides a method for preparing a co-crystal of abscisic acid and betaine with high photostability and drought resistance, comprising the following steps: mixing abscisic acid, betaine, and an organic solvent to obtain a mixed solution; evaporating and crystallizing the mixed solution to obtain the co-crystal of abscisic acid and betaine. This invention uses the natural plant alkaloid betaine as a ligand, which has good safety. Compared with synthetic chemicals, natural ligands generally have lower toxicity to the environment and organisms, reducing potential harm to the ecosystem. The co-crystal disclosed in this invention has significantly higher solubility than abscisic acid. This increased solubility not only facilitates the packaging, transportation, and use of the formulation but also means that plants can more effectively absorb abscisic acid, thereby rapidly exerting its biological activity. The co-crystal disclosed in this invention significantly improves the stability of abscisic acid under ultraviolet light irradiation, thereby reducing the photodegradation of abscisic acid. The co-crystal disclosed in this invention enhances the drought resistance of plants. This enhanced drought resistance may result from the synergistic effect of multiple mechanisms, including stomatal regulation, root development, osmotic pressure regulation, enhanced antioxidant capacity, and regulation of gene expression.

[0084] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a eutectic of abscisic acid and betaine with high photostability and drought resistance, characterized in that, Includes the following steps: (1) Mix abscisic acid, betaine and organic solvent to obtain a mixed solution; (2) The abscisic acid and betaine eucrystalline solution is obtained by evaporating and crystallizing the mixed solution; In step (1), the molar ratio of abscisic acid to betaine is 4:1 to 20:1; In step (1), the molar ratio of abscisic acid to organic solvent is 1:1400 to 1:2700; The organic solvent in step (1) is ethanol; The mixing temperature in step (1) is 25~30℃; The evaporation and crystallization temperature in step (2) is 25~30℃, and the evaporation and crystallization time is 30~35h; The crystal habit of the abscisic acid and betaine eutectic in step (2) is needle-shaped.

2. The abscisic acid and betaine co-crystal obtained by the preparation method of the abscisic acid and betaine co-crystal with high photostability and drought resistance as described in claim 1.

3. The application of the abscisic acid and betaine co-crystal with high photostability and drought resistance as described in claim 2 in plant growth regulators.

Images