Synergist for improving drought tolerance of corn as well as preparation method and application of synergist

Abstract

The invention discloses a synergist for improving drought tolerance of corn and a preparation method and application of the synergist, and belongs to the technical field of fertilizer synergism. Silk fibroin liquid, hyaluronic acid, calcium chloride and compound trace elements serve as raw materials, rapid closing of air holes is adjusted, osmotic potential is reduced, expression of cell wall elastin XTH is enhanced, and the drought tolerance of corn is improved. The oxidation resistance of corn plants is improved, and drought stress is resisted through the cooperation of three mechanisms of low water loss, high water retention and strong oxidation resistance. The synergist for improving the drought tolerance of the corn, which is prepared by the invention, is respectively sprayed in a seedling stage, a jointing stage and a large horn mouth stage, so that the drought tolerance of the corn is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of plant cultivation technology, specifically to an synergist for improving the drought resistance of maize, its preparation method, and its application. Background Technology

[0002] Plant drought resistance refers to the ability of terrestrial plants to survive and grow in arid environments. Sustained high temperatures or reduced soil moisture can cause varying degrees of drought stress to plants. Drought stress is divided into two types: soil drought, caused by soil moisture loss, and atmospheric drought, caused by high temperature and low humidity. Drought can inhibit photosynthesis, disrupt metabolism, and damage organs, specifically manifested as the death of older leaves, damage to embryonic tissues, and reduced yield. Plants cope with drought through life cycle adjustments to avoid drought, morphological characteristics to resist drought (such as developed root systems and leaf degeneration), and physiological regulation (osmotic regulation and stomatal control). In agricultural production, multiple measures are taken to improve crop drought resistance, including drought hardening, chemical regulation (such as CaCl2 seed soaking), and variety selection.

[0003] For maize plants, drought stress exhibits different characteristics at different growth stages. Seedlings are prone to leaf curling, drying, and embryo rot. Mature plants show stunting, yellowing leaf margins, and brown spots. Existing control measures mainly alleviate the effects of high temperature and drought through water conservancy infrastructure construction, drought-resistant variety selection, seed dressing with bio-fertilizers, timely irrigation and cooling, artificial pollination, and foliar spraying of nutrient solutions. Regarding the aforementioned method of foliar spraying of nutrient solutions, invention patent application CN105859438A discloses a plant selenium- and zinc-enriched nutrient solution, which consists of 0.1%~1% Se, 0.1%~1% Zn, 0.1%~1% B, 0.1%~1% Mn, 0.1%~1% Cu, 0.1%~1% Mo, 5%~20% organic acid (highly active fulvic acid), 0.1%~1% Ti, 0.1%~1% vitamins, with the remainder being highly effective adjuvants. Although the above-mentioned nutrient solution has drought resistance, making the plant's water absorption rate greater than its transpiration rate, thereby improving the drought resistance of corn plants, the drought resistance of corn plants under drought stress is still not good. Summary of the Invention

[0004] This invention provides an synergist for improving drought resistance in maize, its preparation method, and its application. It effectively solves the technical problem that while existing nutrient solutions can achieve a certain degree of drought resistance, their effect is still not ideal. This invention uses silk fibroin solution, hyaluronic acid, calcium chloride, and complex trace elements as raw materials to regulate the rapid closure of stomata, reduce osmotic potential, enhance the expression of cell wall elastin XTH, and improve the antioxidant capacity of maize plants. It works synergistically to resist drought stress through three mechanisms: less water loss, more water retention, and strong antioxidant capacity.

[0005] The first objective of this invention is to provide an synergist for improving the drought resistance of corn, which is prepared by mixing silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water; the complex trace elements are composed of Zn, Fe, Mn and B; the molar ratio of Zn, Fe, Mn and B is 10:2~4:2~3.5:3~5.

[0006] Based on the synergist for improving corn drought resistance, the mass concentration of the silk fibroin solution is 0.5%~2%, the mass concentration of the hyaluronic acid is 0.1%~0.6%, the concentration of the calcium chloride is 0.09%~0.23%, the mass concentration of the complex trace elements is 0.02%~0.2%, and the balance is water.

[0007] In a preferred embodiment, the concentration of calcium chloride is 0.11% to 0.18%.

[0008] As a preferred embodiment, the silk fibroin solution is prepared by: degumming raw silk with boiling Na2CO3 water, washing to obtain degummed raw silk, dissolving the degummed raw silk with LiBr solution to obtain silk fibroin-LiBr solution, and dialysis the silk fibroin-LiBr solution with water to remove salt to obtain silk fibroin solution.

[0009] In a preferred embodiment, the molecular weight of the silk fibroin is 3kDa to 50kDa; and the average molecular weight of the hyaluronic acid is 0.8MDa to 1.5MDa.

[0010] In a preferred embodiment, the Zn element in the composite trace elements is selected from soluble Zn. 2+ Salt or chelated Zn, Fe element selected from soluble Fe 2+ Salt or chelated Fe, Mn element selected from soluble Mn 2+ The salt or chelated form of Mn, and the element B is H3BO3.

[0011] The second objective of this invention is to provide a method for preparing the synergist for improving drought resistance of corn as described in any of the above claims, comprising the following steps: mixing silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water.

[0012] A third objective of this invention is to provide an application of the synergist described in any one of the above claims for improving corn drought resistance, wherein the specific application method includes the following steps: The synergist for improving corn drought resistance is diluted 5 to 20 times to obtain a synergist solution; the amino acid-containing water-soluble fertilizer is diluted 1000 times to obtain a working solution.

[0013] During the seedling stage, jointing stage and large trumpet stage, the working solution and synergistic solution are sprayed onto the corn leaves simultaneously.

[0014] In a preferred embodiment, the volume ratio of the working solution to the synergistic solution is 3:0.5~1, the spraying dosage is 10L / mu~20L / mu, and the spraying time is 8:00-10:00 AM or 4:00-6:00 PM.

[0015] As a preferred implementation method, spray once every 7 days during the corn seedling stage, and once every 5 to 7 days from the jointing stage to the large trumpet stage.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a synergist for improving drought resistance in maize, composed of silk fibroin solution, hyaluronic acid, calcium chloride, and a complex of trace elements; the complex of trace elements consists of Zn, Fe, Mn, and B. This invention utilizes the synergistic effect of silk fibroin solution and calcium chloride to effectively increase the stomatal closure rate, thereby reducing the water transpiration rate. The combination of silk fibroin solution and hyaluronic acid accumulates proline and soluble sugars, effectively reducing the osmotic potential of water and drawing water into the cells. Simultaneously, it promotes the expression of cell wall elastin XTH, maintaining cell turgor pressure and preventing water loss and collapse, thus achieving highly efficient water retention in maize plant cells. The addition of the complex of trace elements (Zn, Fe, Mn, and B) to the synergist formulation effectively increases the activity of CAT peroxidase, thereby rapidly clearing H2O2 generated by drought stress and reducing membrane lipid peroxidation, thus achieving a strong antioxidant effect on maize plants. In summary, this invention uses silk fibroin solution, hyaluronic acid, calcium chloride, and complex trace elements as raw materials to regulate the rapid closure of stomata, reduce osmotic potential, enhance the expression of cell wall elastin XTH, and improve the antioxidant capacity of maize plants. It works synergistically to resist drought stress through three mechanisms: less water loss, more water retention, and strong antioxidant capacity. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the preparation and application process of the synergist for improving drought resistance in corn according to the present invention. Detailed Implementation

[0018] To enable those skilled in the art to better understand and implement the technical solutions of this invention, the invention is further described below with reference to specific embodiments. However, the embodiments are not intended to limit the invention. Unless otherwise specified, the following test methods and detection methods are conventional methods; unless otherwise specified, the reagents and raw materials are commercially available.

[0019] Existing nutrient solutions for improving drought resistance in maize plants only adjust the degree of stomatal closure to increase the rate of water absorption compared to the rate of water loss through transpiration, thereby raising the water potential within the plant. While these methods can improve drought resistance to some extent, their regulatory mechanisms are limited, resulting in unsatisfactory drought resistance effects. To address these technical problems, this invention provides a synergist for improving drought resistance in maize, its preparation method, and its application.

[0020] The technical solution of the present invention will be described in detail below.

[0021] This invention provides an synergist for improving the drought resistance of maize, such as... Figure 1 As shown, it is prepared by mixing silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water; the complex trace elements are composed of Zn, Fe, Mn and B elements.

[0022] Based on the synergist for improving corn drought resistance, the mass concentration of the silk fibroin solution is 0.5%~2%, the mass concentration of the hyaluronic acid is 0.1%~0.6%, the concentration of the calcium chloride is 0.09%~0.23%, the mass concentration of the complex trace elements is 0.02%~0.2%, and the balance is water.

[0023] In the above technical solution, the synergistic effect of silk fibroin solution and calcium chloride effectively improves the stomatal closure rate, thereby reducing the water transpiration rate. The combination of silk fibroin solution and hyaluronic acid accumulates proline and soluble sugars, effectively reducing the osmotic potential of water and drawing water into the cells. Simultaneously, it promotes the expression of cell wall elastin (XTH), maintaining cell turgor pressure and preventing water loss and collapse, thus achieving highly efficient water retention in maize plant cells. The addition of a complex trace element formula consisting of Zn, Fe, Mn, and B to the synergist formulation effectively enhances the activity of CAT peroxidase, thereby rapidly clearing H2O2 generated by drought stress and reducing membrane lipid peroxidation, thus achieving a strong antioxidant effect on maize plants. In summary, this invention uses silk fibroin solution, hyaluronic acid, calcium chloride, and complex trace elements as raw materials to regulate the rapid closure of stomatal cells, reduce osmotic potential, enhance the expression of cell wall elastin (XTH), and improve the antioxidant capacity of maize plants. It synergistically resists drought stress through three mechanisms: less water loss, more water retention, and strong antioxidant effects. To effectively regulate the degree and duration of stomatal closure in maize plant leaves, the concentration of calcium chloride is 0.11% to 0.18%. During the experimental process, it was found that when the concentration of calcium chloride is less than 0.11% or greater than 0.18%, it is difficult to regulate the duration and frequency of stomatal opening and closing in maize plant leaves, and the expected regulatory effect cannot be achieved.

[0024] To further enhance the activity of catalase in leaves and thus effectively remove H2O2 produced by drought stress, the molar ratio of Zn, Fe, Mn, and B is 10:2~4:2~3.5:3~5. In this complex of trace elements, Zn is selected from soluble Zn. 2+ Salt or chelated Zn, Fe element selected from soluble Fe 2+ Salt or chelated Fe, Mn element selected from soluble Mn 2+ The salt or chelated form of Mn, and the element B is H3BO3.

[0025] It should be noted that the preparation method of the silk fibroin solution is as follows: Silkworm raw silk is degummed using boiling Na2CO3 water, washed to obtain degummed raw silk, and then dissolved in LiBr solution to obtain a silk fibroin-LiBr solution. The silk fibroin-LiBr solution is then subjected to water dialysis to remove salt, yielding the silk fibroin solution. The molecular weight of the silk fibroin is 3kDa~50kDa; the average molecular weight of the hyaluronic acid is 0.8MDa~1.5MDa.

[0026] This invention also provides an application of the above-mentioned synergist for improving corn drought resistance in enhancing corn drought resistance, the specific application method including the following steps: The synergist for improving corn drought resistance is diluted 5 to 20 times to obtain a synergist solution; the amino acid-containing water-soluble fertilizer is diluted 1000 times to obtain a working solution.

[0027] During the seedling stage, jointing stage and large trumpet stage, the working solution and synergistic solution are sprayed onto the corn leaves simultaneously.

[0028] To further enhance the drought resistance effect of the synergist, the volume ratio of the working solution to the synergist is 3:0.5~1, the spraying dosage is 10L / mu~20L / mu, and the spraying time is 8:00-10:00 AM or 4:00-6:00 PM. Spray once every 7 days during the corn seedling stage, and once every 5-7 days from the jointing stage to the large trumpet stage.

[0029] The invention will now be described in detail through the following embodiments and comparative examples.

[0030] In subsequent embodiments of the present invention, the Zn element used is ZnCl2, the Fe element is FeSO4·7H2O, the Mn element is MnSO4·H2O, and the B element is H3BO3.

[0031] The silk fibroin solution used in subsequent embodiments of the present invention was obtained by the following preparation method: 5g of raw silkworm silk was purchased from a local silk company and degummed with boiling water containing 0.5% Na2CO3 for 30 minutes to obtain degummed raw silk. After washing, the degummed raw silk was dissolved in 9.3mol / L LiBr at 60℃ for 4 hours to obtain a silk fibroin-LiBr solution. The silk fibroin-LiBr solution was then dialyzed with deionized water for 48 hours to remove salt, thus obtaining the silk fibroin solution.

[0032] The amino acid-containing water-soluble fertilizer used in this invention is Kangxin Biaosheng amino acid-containing water-soluble fertilizer, purchased from Linyi County Kangxin Chemical Co., Ltd.

[0033] Example 1 An synergist for improving drought resistance in maize, comprising, based on the synergist, 0.5% by mass of silk fibroin solution, 0.1% by mass of hyaluronic acid, 0.11% by mass of calcium chloride, and 0.06% by mass of a complex of trace elements, with the balance being water; the complex of trace elements is composed of ZnCl2, FeSO4·7H2O, MnSO4·H2O, and H3BO3 in a molar ratio of 10:2:2:3.

[0034] The preparation method of the above-mentioned synergist for improving the drought resistance of corn includes the following steps: mixing the above-mentioned silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water.

[0035] Example 2 An synergist for improving drought resistance in maize, comprising, based on the synergist, 1.5% by mass of silk fibroin solution, 0.5% by mass of hyaluronic acid, 0.09% by mass of calcium chloride, and 0.02% by mass of a complex of trace elements, with the balance being water; the complex of trace elements is composed of ZnCl2, FeSO4·7H2O, MnSO4·H2O, and H3BO3 in a molar ratio of 10:3:3:4.

[0036] The preparation method of the above-mentioned synergist for improving the drought resistance of corn includes the following steps: mixing the above-mentioned silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water.

[0037] Example 3 An synergist for improving drought resistance in maize, comprising, based on the synergist, 1.0% by mass of silk fibroin solution, 0.3% by mass of hyaluronic acid, 0.17% by mass of calcium chloride, and 0.1% by mass of a complex of trace elements, with the balance being water; the complex of trace elements is composed of ZnCl2, FeSO4·7H2O, MnSO4·H2O, and H3BO3 in a molar ratio of 10:4:2.5:5.

[0038] The preparation method of the above-mentioned synergist for improving the drought resistance of corn includes the following steps: mixing the above-mentioned silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water.

[0039] Example 4 An synergist for improving drought resistance in maize, comprising, based on the synergist, 2% by mass of silk fibroin solution, 0.2% by mass of hyaluronic acid, 0.22% by mass of calcium chloride, and 0.2% by mass of a complex trace element, with the balance being water; the complex trace element is composed of ZnCl2, FeSO4·7H2O, MnSO4·H2O, and H3BO3 in a molar ratio of 10:2:3.5:3.5.

[0040] The preparation method of the above-mentioned synergist for improving the drought resistance of corn includes the following steps: mixing the above-mentioned silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water.

[0041] Example 5 An synergist for improving drought resistance in maize, comprising, based on the synergist, 1.0% by mass of silk fibroin solution, 0.6% by mass of hyaluronic acid, 0.19% by mass of calcium chloride, and 0.16% by mass of a complex of trace elements, with the balance being water; the complex of trace elements is composed of ZnCl2, FeSO4·7H2O, MnSO4·H2O, and H3BO3 in a molar ratio of 10:2.5:2.5:4.5.

[0042] The preparation method of the above-mentioned synergist for improving the drought resistance of corn includes the following steps: mixing the above-mentioned silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water.

[0043] Example 6 An synergist for improving drought resistance in maize, comprising, based on the synergist, 0.5% by mass of silk fibroin solution, 0.4% by mass of hyaluronic acid, 0.13% by mass of calcium chloride, and 0.08% by mass of a complex of trace elements, with the balance being water; the complex of trace elements is composed of ZnCl2, FeSO4·7H2O, MnSO4·H2O, and H3BO3 in a molar ratio of 10:3.5:2:5.

[0044] The preparation method of the above-mentioned synergist for improving the drought resistance of corn includes the following steps: mixing the above-mentioned silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water.

[0045] Example 7 An synergist for improving drought resistance in maize, comprising, based on the synergist, 2.0% by mass of silk fibroin solution, 0.2% by mass of hyaluronic acid, 0.20% by mass of calcium chloride, and 0.12% by mass of a complex of trace elements, with the balance being water; the complex of trace elements is composed of ZnCl2, FeSO4·7H2O, MnSO4·H2O, and H3BO3 in a molar ratio of 10:4:2:3.

[0046] The preparation method of the above-mentioned synergist for improving the drought resistance of corn includes the following steps: mixing the above-mentioned silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water.

[0047] To further illustrate the technical effects of the present invention, a comparative example is also provided, as follows: Comparative Example 1 The difference compared to Example 3 is that hyaluronic acid is removed.

[0048] An synergist for improving drought resistance in maize, comprising, based on the synergist, 1.0% by mass of silk fibroin solution, 0.17% by mass of calcium chloride, and 0.1% by mass of a complex trace element, with the balance being water; the complex trace element comprises ZnCl2, FeSO4·7H2O, MnSO4·H2O, and H3BO3 in a molar ratio of 10:4:2.5:5.

[0049] The preparation method of the above-mentioned synergist for improving the drought resistance of corn includes the following steps: mixing the above-mentioned silk fibroin solution, calcium chloride and complex trace elements in water.

[0050] Comparative Example 2 The difference from Example 3 is that calcium chloride is replaced with calcium sulfate.

[0051] An synergist for improving drought resistance in maize, comprising, based on the synergist, 1.0% by mass of silk fibroin solution, 0.3% by mass of hyaluronic acid, 0.17% by mass of calcium sulfate, and 0.1% by mass of a complex of trace elements, with the balance being water; the complex of trace elements is composed of ZnCl2, FeSO4·7H2O, MnSO4·H2O, and H3BO3 in a molar ratio of 10:4:2.5:5.

[0052] The preparation method of the above-mentioned synergist for improving the drought resistance of corn includes the following steps: mixing the above-mentioned silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water.

[0053] Comparative Example 3 The difference compared to Example 3 is that element B in the composite trace elements is removed.

[0054] An synergist for improving drought resistance in maize, comprising, based on the synergist, 1.0% by mass of silk fibroin solution, 0.3% by mass of hyaluronic acid, 0.17% by mass of calcium chloride, and 0.1% by mass of a complex of trace elements, with the balance being water; the complex of trace elements is composed of ZnCl2, FeSO4·7H2O, and MnSO4·H2O in a molar ratio of 10:4:2.5.

[0055] The preparation method of the above-mentioned synergist for improving the drought resistance of corn includes the following steps: mixing the above-mentioned silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water.

[0056] The performance of the synergists for improving drought resistance of maize provided in the above embodiments and comparative examples was tested, and the testing process and results are as follows.

[0057] I. Experimental Preparation: Corn plant preparation: In this embodiment, corn was used as the plant test material, the variety being Zhongyu 303, purchased from the Institute of Crop Science, Chinese Academy of Agricultural Sciences. The corn seeds were disinfected successively with 70% alcohol for 30 seconds, then with 10% sodium hypochlorite for 10 minutes, rinsed five times with sterile water, and dried with sterile filter paper before use.

[0058] II. Experimental Design: Corn seeds of uniform size and morphology were used for experimental treatment. Eight groups of experimental plants were set up, designated as Experiment 1, Experiment 2, Control 1, Control 2, Control 3, Distilled Water Group, and Blank Control Group, with 30 plants in each group. Experiment 1 and Experiment 2 used the synergists for improving corn drought resistance from Examples 1 and 3, respectively, designated as Group A1 and Group A2; Control 1 used the synergist for improving corn drought resistance from Comparative Example 1, designated as Group B; Control 2 used the synergist for improving corn drought resistance from Comparative Example 2, designated as Group C; Control 3 used the synergist for improving corn drought resistance from Comparative Example 3, designated as Group D; Distilled Water Group received only foliar spraying with distilled water, designated as Group E; and Blank Control Group received no foliar spraying, designated as Group F.

[0059] Spraying treatment was carried out according to the above groups. The spraying steps were as follows: During the corn seedling stage, jointing stage to large trumpet stage, from 8:00 to 10:00 am or from 4:00 to 6:00 pm, the corn leaves of each group were sprayed with the synergistic solution diluted 10 times and the working solution containing amino acid water-soluble fertilizer diluted 1000 times, according to the volume ratio of synergistic solution to working solution of 1:3. The spraying amount was 15L / mu. Spraying was carried out once every 7 days during the seedling stage and once every 6 days during the jointing stage to large trumpet stage.

[0060] Drought simulation treatment: Drought stress was simulated by applying 20% ​​PEG6000 by mass. The plants were irrigated with 20% PEG6000 by mass every 2 days for 12 consecutive days. The spraying and drought treatment were carried out simultaneously. In addition, a control group of experimental plants with the same growth and size was set up as a normal growth condition control group, without drought simulation, and was designated as group G.

[0061] After the above treatments are completed, the relative moisture content of the maize leaves in each group is calculated. The specific method is as follows: Relative moisture content analysis: After treatment, all leaves remaining from the entire plant except for the first leaf were taken and weighed immediately, recording the fresh weight. The leaves were then placed in 50mL centrifuge tubes, and an appropriate amount of water was added to completely immerse them. After absorbing water for 3 hours, the leaves were wiped dry with absorbent paper and weighed again; this was the saturated fresh weight. Sampling was repeated 5 times for each treatment group. The samples were then placed in an oven and dried at 60℃ until constant weight, and the dry weight of the leaves was recorded.

[0062] Moisture content is calculated using the following formula: Relative moisture content = (Y1-Y2) / (Y3-Y2)×100%; In the formula, Y1 represents fresh weight, Y2 represents dry weight, and Y3 represents saturated fresh weight.

[0063] The activity of catalase in maize seedling leaves of each group was detected by ultraviolet spectrophotometry. Since hydrogen peroxide has a characteristic absorption peak at a wavelength of 240 nm, the activity of catalase (CAT) was calculated by measuring the change in absorbance.

[0064] III. Analysis of Experimental Results: The effects of each group of synergists used to improve the drought resistance of maize on the relative water content of maize leaves under drought stress, the catalase activity of maize leaves during the seedling stage, and the maize yield of each group are shown in Table 1.

[0065] Table 1. Comparison of corn performance after using the synergist of the embodiments and comparative examples of the present invention.

[0066] As shown in Table 1, after using the synergist provided by this invention to improve the drought resistance of maize, the relative water content of maize leaves, catalase activity, and yield per acre of maize all achieved better technical results under drought stress. However, when the components in the synergist were adjusted, the drought resistance of maize plants under drought stress decreased significantly. Compared with Example 3, the relative water content of maize leaves and catalase activity in Comparative Examples 1 to 3 decreased significantly, and the maize crop yield also decreased considerably. The reasons are analyzed as follows: In Comparative Example 1, hyaluronic acid was removed from the synergist component used to improve corn drought resistance. Because the components in the synergist provided by this invention have a strong synergistic effect, hyaluronic acid, when combined with silk fibroin solution, accumulates proline and soluble sugars, effectively reducing the osmotic potential of water and introducing water into the cells. On the other hand, it promotes the expression of cell wall elastin XTH, maintaining cell turgor pressure and preventing water loss and collapse. Therefore, it achieves efficient water retention in corn plant cells. Removing hyaluronic acid in Comparative Example 1 leads to an imbalance in its synergistic effect with silk fibroin solution, directly affecting cell water storage and retention, making it difficult to maintain the turgor state. This results in a significant decrease in corn drought resistance. As the ability to resist drought stress decreases, hydrogen peroxide content gradually accumulates in the leaves, further affecting the plant's drought resistance.

[0067] In Comparative Example 2, calcium chloride in the synergist component used to improve corn drought resistance was replaced with calcium sulfate. Calcium chloride, in synergy with silk fibroin solution, effectively increased the stomatal closure rate, thereby reducing the transpiration rate. However, data from Table 1 show that replacing calcium chloride with calcium sulfate significantly affected the relative water content of corn leaves, catalase activity, and crop yield. Mechanistically, although calcium chloride and calcium sulfate are both calcium salts, their anions are different. When synergistically combined with silk fibroin solution, they cannot effectively regulate the opening and closing of leaf stomata, resulting in a higher transpiration rate and decreased plant drought resistance.

[0068] In Comparative Example 3, the B element in the complex trace elements of the synergist used to improve corn drought resistance was removed, i.e., H3BO3 was not added. Obviously, the catalase activity in corn leaves decreased significantly. This is because the addition of the complex trace elements composed of Zn, Fe, Mn and B elements to the synergist formula can effectively improve the activity of catalase, thereby quickly clearing H2O2 produced by drought stress, reducing membrane lipid peroxidation, and thus achieving a strong antioxidant effect on corn plants. However, the removal of the B element in the complex trace elements in Comparative Example 3 resulted in the inability to effectively improve the activity of catalase, thus reducing the drought resistance of the plants.

[0069] In summary, the synergist for improving corn drought resistance provided by this invention can significantly enhance the drought tolerance of corn plants, alleviate the impact of drought on corn plants, and increase the relative water content of corn plants under drought stress. This indicates that the synergist for improving corn drought resistance provided by this invention can be used as a foliar spray to enhance plant drought resistance, laying the foundation for crop cultivation in arid environments.

[0070] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A synergist for improving drought tolerance in maize, characterized by, It is prepared by mixing silk fibroin solution, hyaluronic acid, calcium chloride and complex trace elements in water; the complex trace elements are composed of Zn, Fe, Mn and B; the molar ratio of Zn, Fe, Mn and B is 10:2~4:2~3.5:3~5; Based on the synergist for improving corn drought resistance, the mass concentration of the silk fibroin solution is 0.5%~2%, the mass concentration of the hyaluronic acid is 0.1%~0.6%, the concentration of the calcium chloride is 0.09%~0.23%, the mass concentration of the complex trace elements is 0.02%~0.2%, and the balance is water.

2. The synergist for improving drought tolerance of corn according to claim 1, characterized by, The concentration of calcium chloride is 0.11% to 0.18%.

3. The synergist for improving drought tolerance of corn according to claim 1, characterized by, The preparation method of the silk fibroin solution is as follows: degumming the raw silk of silkworms with boiling water of Na2CO3, washing it to obtain degummed raw silk, dissolving the degummed raw silk with LiBr solution to obtain silk fibroin-LiBr solution, and dialysis the silk fibroin-LiBr solution with water to remove salt to obtain silk fibroin solution.

4. The synergist for improving drought tolerance of corn according to claim 1, wherein The silk fibroin has a molecular weight of 3kDa to 50kDa; the hyaluronic acid has an average molecular weight of 0.8MDa to 1.5MDa.

5. The synergist for improving drought tolerance of corn according to claim 1, wherein The complex microelement, the Zn element is selected from soluble Zn 2+ salt or chelated Zn, the Fe element is selected from soluble Fe 2+ salt or chelated Fe, the Mn element is selected from soluble Mn 2+ salt or chelated Mn, and the B element is H3BO3.

6. A method for preparing the synergist for improving drought tolerance of corn according to any one of claims 1 to 5, characterized by, Includes the following steps: The solution is obtained by mixing silk fibroin, hyaluronic acid, calcium chloride and complex trace elements in water.

7. The application of the synergist for improving drought resistance in maize according to any one of claims 1 to 5 in improving drought resistance in maize, characterized in that, The specific application method includes the following steps: The synergist for improving corn drought resistance is diluted 5 to 20 times to obtain a synergistic solution; the amino acid-containing water-soluble fertilizer is diluted 1000 times to obtain a working solution. During the seedling stage, jointing stage and large trumpet stage, the working solution and synergistic solution are sprayed onto the corn leaves simultaneously.

8. The application of the synergist for improving drought resistance in maize according to claim 7 in improving maize drought resistance, characterized in that, The volume ratio of the working solution to the synergistic solution is 3:0.5~1, the spraying dosage is 10L / mu~20L / mu, and the spraying time is 8:00-10:00 AM or 4:00-6:00 PM.

9. The application of the synergist for improving drought resistance in maize according to claim 7 in improving maize drought resistance, characterized in that, Spray once every 7 days during the corn seedling stage, and once every 5 to 7 days from the jointing stage to the large trumpet stage.

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