Seaweed oligosaccharide chelated zinc as well as preparation method and application thereof

Abstract

The invention discloses seaweed oligosaccharide chelated zinc as well as a preparation method and application thereof. According to the preparation method, gradient heating is matched with pH adjustment, and the seaweed oligosaccharide chelated zinc with the extremely high chelation rate can be obtained. Based on the seaweed oligosaccharide chelated zinc, the seaweed oligosaccharide chelated zinc is compounded with other reagents to obtain the plant growth regulator. All the components of the plant growth regulator can achieve synergistic interaction, and the better yield and zinc increasing effect on rice compared with an existing traditional ionic state zinc fertilizer zinc sulfate heptahydrate and a conventional chelating state zinc fertilizer EDTA chelated zinc is achieved. The invention further provides a method for using the specific plant growth regulator in the early tillering stage and the early heading stage, zinc absorption can be further promoted by using the specific plant growth regulator in sequence, the rice yield is increased, the tillering number of rice is increased, and the zinc content of rice grains is increased.

Description

Technical Field

[0001] Zinc is an essential element for crop growth and development. It affects the synthesis of auxin, and zinc deficiency leads to stunted growth and hinders normal plant development. Zinc is also an essential micronutrient for humans, crucial for growth, development, and health. Approximately half the world's population has insufficient zinc intake, primarily due to grain crops being grown in zinc-deficient soils, resulting in low zinc content in the grains. Therefore, supplementing or increasing the zinc content of edible parts of crops through zinc fertilization is of great significance for meeting people's needs and promoting human health.

[0002] In traditional agricultural production, zinc fertilizer is mainly applied to the soil to increase the zinc content of crops. However, zinc has poor mobility and utilization in soil, and it is easily fixed in alkaline soils, resulting in generally low availability. Therefore, in recent years, foliar spraying has been widely used to improve the utilization rate of zinc fertilizer. However, ionic zinc fertilizers applied by foliar spraying can easily burn crop leaves, and the absorption efficiency is not significantly improved. Existing chelated zinc fertilizers, such as EDTA chelated zinc, are not easily degraded in the environment and plants, and excessive EDTA can be toxic. Therefore, it is crucial to develop new zinc fertilizer products that are non-toxic and harmless, can significantly improve zinc absorption capacity, and avoid damage to crops without reducing the application concentration.

[0003] In current agricultural technology, zinc-containing bioregulators are widely used to improve rice growth. For example, some liquid fertilizers based on zinc chelated with ethylenediaminetetraacetic acid (EDTA) can supplement fertilization programs and prevent nutrient imbalances. Zinc, an indispensable element for plant growth, is a precursor to tryptophan and plays a crucial role in auxin synthesis. It also plays a key role in nitrogen metabolism, phosphorus absorption, and promoting plant respiration. In pot experiments, zinc oxide nanoparticles, with different zinc dosages, have shown to effectively increase rice grain yield, promote dry matter accumulation, and enhance grain zinc content. Furthermore, there are biofertilizers containing zinc-dissolving bacteria. These bacteria produce organic acids that convert insoluble zinc compounds in the soil, such as zinc sulfide, zinc oxide, and zinc carbonate, into zinc ions that can be absorbed and utilized by plants, thereby increasing the availability of zinc in the soil and positively impacting rice growth. In terms of application methods, zinc-containing bioregulators can be applied in multiple ways. For soil application, a certain amount of bioregulator is usually mixed with fully decomposed farmyard manure, compost, or field soil. For drip irrigation systems, a specific amount of zinc-containing bioregulator can also be mixed into the irrigation water. Foliar spraying is also a common method, such as spraying sugar alcohol chelated zinc preparations when treating or preventing zinc deficiency in plants. However, these zinc-containing bioregulators are not without their flaws. The relatively high cost of some zinc-containing bioregulators limits their large-scale application. Regarding bioavailability, some zinc compounds, due to their molecular structure, have poor absorption and utilization efficiency in plants. Furthermore, some zinc-containing bioregulators have stability issues; they may decompose under humid or high-temperature conditions, reducing their effectiveness. Improper dosage control during use can also lead to negative effects. For example, excessive use of zinc supplements may cause an imbalance in the zinc-to-copper ratio in plants, interfering with the absorption of other nutrients such as calcium, iron, and phosphorus, and affecting normal plant growth and development. Simultaneously, some bioregulators may also pose potential environmental risks, such as impacting soil microbial community structure.

[0004] As a small-molecule physiologically active substance, seaweed oligosaccharides regulate plant cell physiological activities, improve leaf surface conditions, and facilitate nutrient absorption. Seaweed oligosaccharides also have good wetting and emulsifying properties; compared to ionic zinc fertilizers, seaweed oligosaccharide-chelated zinc is more easily adsorbed on the leaf surface, enhancing the plant's ability to absorb nutrients evenly. While there have been sporadic reports on seaweed oligosaccharide-chelated zinc in the pharmaceutical and feed fields, basic research in rice production remains very lacking.

[0005] Therefore, there is an urgent need for new zinc-containing bioregulators and reasonable and effective application methods. Summary of the Invention

[0006] The primary objective of this invention is to overcome the shortcomings and deficiencies of the prior art and to provide an alginate oligosaccharide chelated zinc (AOS-Zn) and its preparation method and application.

[0007] A second objective of the present invention is to provide a plant growth regulator containing the above-mentioned AOS-Zn.

[0008] A third objective of this invention is to provide a method for regulating plant growth using the aforementioned AOS-Zn plant growth regulator.

[0009] The objective of this invention is achieved through the following technical solution: A method for preparing seaweed oligosaccharide chelated zinc includes the following steps: (1) Mix the seaweed oligosaccharide aqueous solution with the zinc nitrate hexahydrate aqueous solution, adjust the pH to 7, stir at 40℃ for 15 minutes, adjust the pH to 5, stir at 55℃ for 45 minutes, adjust the pH to 6.5, stir at 70℃ for 45 minutes, and lower the temperature to 0℃ to terminate the reaction to obtain the crude solution of seaweed oligosaccharide chelated zinc. (2) Adjust the pH to 6, add sodium bicarbonate to the crude solution of seaweed oligosaccharide chelated zinc to precipitate the unchelated zinc, centrifuge, and collect the supernatant; (3) Repeat step (2) until no precipitate is produced. Adjust the pH to 6.5 with acid, concentrate, and dry to obtain purified seaweed oligosaccharide chelated zinc.

[0010] Furthermore, the molar ratio of seaweed oligosaccharide and zinc nitrate hexahydrate mentioned in step (1) is 1 to 3:1; even further, it is 1.5:1.

[0011] Furthermore, the concentration of the seaweed oligosaccharide aqueous solution mentioned in step (1) is 0.005 to 0.02 mol / L.

[0012] Furthermore, the concentration of the zinc nitrate hexahydrate aqueous solution mentioned in step (1) is 0.005 to 0.02 mol / L.

[0013] Further, the amount of sodium bicarbonate added in step (2) is based on HCO3 2- Zn 2+ A molar ratio of 2 to 3:1 was added, in which Zn 2+ The Zn in zinc nitrate hexahydrate in step (1) 2+ The amount of substance; furthermore, the amount of sodium bicarbonate added in step (2) is based on HCO3 2- Zn 2+ The molar ratio of 2.2 to 1 was added.

[0014] Furthermore, the centrifugation described in step (2) is centrifugation at 4000 rpm for 10 min.

[0015] Furthermore, the acid in step (3) includes hydrochloric acid.

[0016] A seaweed oligosaccharide chelated zinc was prepared by the above method.

[0017] The above-mentioned application of seaweed oligosaccharide chelated zinc in regulating plant growth.

[0018] Furthermore, the regulation of plant growth includes at least one of increasing rice yield, increasing the number of rice tillers, and increasing the zinc content of rice grains.

[0019] The above-mentioned application of seaweed oligosaccharide chelated zinc in the preparation of plant growth regulators.

[0020] Furthermore, the plant growth regulator's regulatory effects include at least one of increasing rice yield, increasing rice tiller number, and increasing the zinc content of rice grains.

[0021] A plant growth regulator containing the aforementioned seaweed oligosaccharide chelated zinc.

[0022] Furthermore, the plant growth regulator's regulatory effects include at least one of increasing rice yield, increasing rice tiller number, and increasing the zinc content of rice grains.

[0023] Furthermore, the content of seaweed oligosaccharide chelated zinc in the plant growth regulator is 1.5–3 g / L; even further, it is 3 g / L; Furthermore, the plant growth regulator further contains 5 mg / L of GA3 and 5 mg / L of GA4; even further, the plant growth regulator further contains 500–1000 mg / L of anhydrous ethanol, 500–800 mg / L of Tween-20, 500–750 mg / L of ascorbic acid, 500–750 mg / L of citric acid, 500–1000 mg / L of chitosan, and 500 mg / L of acetic acid; the balance being water. Most preferably, the plant growth regulator contains 3 g / L of seaweed oligosaccharide chelated zinc, 5 mg / L of GA3, 5 mg / L of GA4, 750 mg / L of anhydrous ethanol, 600 mg / L of Tween-20, 600 mg / L of ascorbic acid, 750 mg / L of citric acid, 1000 mg / L of chitosan, and 500 mg / L of acetic acid; the balance being water.

[0024] Furthermore, the plant growth regulator also contains 1.5 mg / L 6-BA and 5 mg / L GA3; even further, the plant growth regulator also contains 0.025–0.035 mg / L brassinolide, 500–1000 mg / L anhydrous ethanol, 500–800 mg / L Tween-20, 500–750 mg / L ascorbic acid, 500–750 mg / L citric acid, 500–1000 mg / L chitosan, and 500 mg / L acetic acid; the balance is water. Most preferably, the plant growth regulator contains 3 g / L seaweed oligosaccharide chelated zinc, 1.5 mg / L 6-BA, 5 mg / L GA3, 0.03 mg / L brassinolide, 750 mg / L anhydrous ethanol, 600 mg / L Tween-20, 600 mg / L ascorbic acid, 750 mg / L citric acid, 1000 mg / L chitosan, and 500 mg / L acetic acid; the balance being water.

[0025] A method for regulating plant growth includes the following steps: At the early tillering stage, apply the above-mentioned plant growth regulator containing 6-BA and GA3 as a foliar spray at a rate of 20 kg / mu / time. At the early heading stage, apply the above-mentioned plant growth regulator containing GA3 and GA4 as a foliar spray at a rate of 20 kg / mu / time.

[0026] Furthermore, the specific application time for the initial tillering stage is 16 days after transplanting, and the specific application time for the initial heading stage is 60 days after transplanting.

[0027] Furthermore, the regulation of plant growth includes at least one of increasing rice yield, increasing the number of rice tillers, and increasing the zinc content of rice grains.

[0028] The present invention has the following advantages and effects compared with the prior art: (1) This invention discloses a seaweed oligosaccharide chelated zinc and its preparation method, which can obtain seaweed oligosaccharide chelated zinc with extremely high chelation rate.

[0029] (2) The purified seaweed oligosaccharide chelated zinc prepared in this invention has better zinc absorption efficiency and better compatibility with weakly alkaline fertilizers compared with the unpurified zinc.

[0030] (3) Based on the prepared seaweed oligosaccharide chelated zinc, the present invention has developed a plant growth regulator and a method of application. The plant growth regulator of the present invention has better yield and zinc increase effect than the existing traditional ionic zinc fertilizer heptahydrate zinc sulfate and conventional chelated zinc fertilizer EDTA chelated zinc.

[0031] (4) The plant growth regulator of the present invention can be used in sequence at the early tillering stage and the early heading stage to synergistically promote zinc absorption, increase rice yield, increase the number of rice tillers and increase the zinc content of rice grains. Attached Figure Description

[0032] Figure 1 This is a physical image of the AOS-Zn prepared in Example 1.

[0033] Figure 2 This is a diagram showing the precipitation of the mixed solutions in each treatment in Example 4.

[0034] Figure 3 The image shows the growth of rice in each treatment in Example 10. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0036] Unless otherwise specified, all embodiments of the present invention use the "Heguang Simiao" conventional japonica rice variety, and the cultivation and management refer to the single-season rice planting standards in the middle and lower reaches of the Yangtze River.

[0037] Example 1: Preparation method of AOS-Zn 1.1 A method for preparing seaweed oligosaccharide chelated zinc (AOS-Zn), comprising the following steps: (1) Dissolve 5g of seaweed oligosaccharide powder in 1L of deionized water to prepare a seaweed oligosaccharide mother liquor with a concentration of 0.01mol / L; dissolve 3g of zinc nitrate hexahydrate in 1L of deionized water to prepare a zinc source mother liquor with a concentration of 0.01mol / L.

[0038] (2) Gradient temperature increase combined with pH adjustment reaction The seaweed oligosaccharide mother liquor and zinc source mother liquor were mixed at a molar ratio of 1.5:1. The pH of the mixture was adjusted to 7, and pre-chelation was carried out at 40°C for 15 minutes on a constant temperature magnetic stirrer; the pH of the mixture was adjusted to 5, and chelation was carried out at 55°C for 45 minutes on a constant temperature magnetic stirrer; the pH of the mixture was adjusted to 6.5, and chelation was carried out at 70°C for 45 minutes on a constant temperature magnetic stirrer. Finally, the reaction was terminated by placing the mixture in an ice-water mixture to obtain a crude solution of seaweed oligosaccharide chelated zinc.

[0039] (3) Purification of crude solution Adjust the pH of the crude solution to 6, and add HCO3- to the crude solution. 2- Sodium bicarbonate (NaHCO3) was slowly added at a molar ratio of Zn²⁺ = 2.2:1, and the mixture was stirred slowly at room temperature for 60 minutes to precipitate the unchelated zinc as basic zinc carbonate. The mixture was centrifuged at 4000 rpm for 10 minutes, and the supernatant was collected. Step (3) was repeated until no precipitate was formed, at which point the purification was considered complete. The pH was adjusted to 6.5 with hydrogen chloride solution to obtain a refined solution.

[0040] (4) Drying of the solution The obtained purified solution was transferred to a rotary evaporator and concentrated under reduced pressure at 40°C and 20 kPa until the liquid volume was reduced to 1 / 10 of its original volume. The concentrate was then transferred to a freeze dryer and pre-frozen at -80°C for 2 hours, followed by freeze-drying at 20 Pa and -40°C for 12 hours until the ice crystals disappeared, and finally dried at 5 Pa and 25°C to constant weight to obtain seaweed oligosaccharide chelated zinc powder, which has the following appearance: Figure 1 As shown.

[0041] 1.2 The specific method for determining the chelation rate of AOS-Zn is as follows: The zinc concentration of the zinc source mother liquor used in step (1) of 1.1 was determined by ICP-MS and recorded as C0. The zinc concentration of the seaweed oligosaccharide mother liquor used in step (1) of 1.1 was determined by ICP-MS and recorded as C1. The zinc concentration of the purified solution in step (3) of 1.1 was determined by ICP-MS and recorded as C2. The chelation rate (W) was calculated using the formula W=C2 / (C0-C1).

[0042] Example 2: The effect of gradient heating combined with pH adjustment.

[0043] Four groups of chelated zinc were prepared according to the method in 1.1 of Example 1. The difference between the four groups is that the processing steps in step (2) are adjusted as follows: "adjust the pH of the mixture to 7 and pre-chelate at 40°C for 15 minutes on a constant temperature magnetic stirrer; adjust the pH of the mixture to 5 and chelate at 55°C for 45 minutes on a constant temperature magnetic stirrer; adjust the pH of the mixture to 6.5 and chelate at 70°C for 45 minutes on a constant temperature magnetic stirrer". The specific processing settings are as follows: Treatment A: Adjust the pH of the mixture to 5 and chelate it at 55°C for 90 minutes on a constant temperature magnetic stirrer.

[0044] Treatment B: Adjust the pH of the mixture to 6.5 and chelate it at 70°C for 90 minutes on a constant temperature magnetic stirrer.

[0045] Treatment C: First, adjust the pH of the mixture to 5, and chelate it at 55°C for 45 minutes on a constant temperature magnetic stirrer. Then, adjust the pH of the mixture to 6.5, and chelate it at 70°C for 45 minutes on a constant temperature magnetic stirrer.

[0046] Treatment D: Adjust the pH of the mixture to 7 and pre-chelate at 40°C for 15 minutes on a constant temperature magnetic stirrer; adjust the pH of the mixture to 5 and chelate at 55°C for 45 minutes on a constant temperature magnetic stirrer; adjust the pH of the mixture to 6.5 and chelate at 70°C for 45 minutes on a constant temperature magnetic stirrer (same as Example 1).

[0047] Table 1. Effects of gradient temperature increase combined with pH adjustment on improving chelation rate

[0048] Example 3: Effect of AOS-Zn purification on zinc absorption in rice grains The settings are as follows: Treatment of unpurified AOS-Zn: The preparation conditions are the same as in Example 1, 1.1, except that the purification step (3) is omitted.

[0049] Purification of AOS-Zn: The preparation conditions are the same as in Example 1, Section 1.1.

[0050] Each treatment's AOS-Zn was prepared into a 0.3% (w / v) aqueous solution and applied at a rate of 20 kg / mu / time, once uniformly to the leaves using a backpack sprayer at the early tillering stage and the early heading stage. The specific application time for the early tillering stage was 16 days after transplanting, and the specific application time for the early heading stage was 60 days after transplanting. All field trials were conducted with three replicates using a randomized block design, with a plot area of ​​30 m². Yield was measured after harvest, and grain zinc content was determined by atomic absorption spectrometry.

[0051] Table 2. Effects of purified AOS-Zn on increasing zinc concentration in rice grains.

[0052] Example 4: Purification of AOS-Zn and its compatibility with weakly basic pesticides Matrine (pH 7.5–8.0), a commonly used plant-derived broad-spectrum insecticide, and kasugamycin (pH 7.5–8.5), a commonly used antibiotic broad-spectrum fungicide, were selected as weakly alkaline pesticides.

[0053] The settings are as follows: Treatment A: The unpurified AOS-Zn from Example 3 was prepared into a 0.3% (w / v) aqueous solution, and matrine was added to bring the final concentration of matrine in the solution to 100 mg / L. Treatment B: The unpurified AOS-Zn from Example 3 was prepared into a 0.3% (w / v) aqueous solution, and kasugamycin was added to bring the final concentration of kasugamycin in the solution to 20 mg / L. Treatment C: The AOS-Zn prepared according to 1.1 of Example 1 was prepared into a 0.3% (w / v) aqueous solution, and matrine was added to bring the final concentration of matrine in the solution to 100 mg / L. Treatment D: The AOS-Zn prepared according to 1.1 of Example 1 was prepared into a 0.3% (w / v) aqueous solution, and kasugamycin was added to bring the final concentration of kasugamycin in the solution to 20 mg / L. The results of mixing each treatment are as follows. Figure 2 As shown.

[0054] The solutions obtained from the four treatments were applied at a rate of 20 kg / mu / time, and sprayed evenly onto the leaves once each at the early tillering and early heading stages using a backpack sprayer. The specific application time for the early tillering stage was 16 days after transplanting, and the specific application time for the early heading stage was 60 days after transplanting. All field trials were conducted with three replicates using a randomized block design, with a plot area of ​​30 m². Yield was measured after harvest, and grain zinc content was determined by atomic absorption spectrometry.

[0055] Table 3. Effects of purified AOS-Zn on improving compatibility with weakly alkaline pesticides

[0056] From Table 3 and Figure 2 It can be seen that unpurified AOS-Zn produces a precipitate when mixed with weakly alkaline pesticides, which weakens the zinc-enhancing effect. However, purified AOS-Zn does not produce a precipitate, indicating that purified AOS-Zn has good compatibility with weakly alkaline pesticides and can be applied together, which is convenient for agricultural production.

[0057] Example 5: Effect of different chelation rates of AOS-Zn on zinc absorption in rice grains The settings are as follows: Low chelation rate treatment: The preparation conditions for low chelation rate AOS-Zn were the same as in Example 1, step 1.1, except that step (2) was adjusted as follows: the seaweed oligosaccharide mother liquor and the zinc source mother liquor were mixed in a molar ratio of 1.5:1. The pH of the mixture was adjusted to 5, and the mixture was chelated at 55°C for 90 minutes on a constant temperature magnetic stirrer. The reaction was then terminated by placing the mixture in an ice-water mixture to obtain a crude solution of low chelation rate seaweed oligosaccharide chelated zinc (chelation rate of 51.7%).

[0058] Medium chelation rate treatment: The preparation conditions for medium chelation rate AOS-Zn are the same as in Example 1, step 1.1, except that step (2) is adjusted as follows: the seaweed oligosaccharide mother liquor and the zinc source mother liquor are mixed in a molar ratio of 1:1. The pH of the mixture is adjusted to 7.5, and chelated at 40°C for 30 minutes on a constant temperature magnetic stirrer; the pH of the mixture is adjusted to 7, and chelated at 50°C for 60 minutes on a constant temperature magnetic stirrer. Finally, the reaction is terminated by placing it in an ice-water mixture to obtain a crude solution of medium chelation rate seaweed oligosaccharide chelated zinc (chelation rate of 77.4%).

[0059] High chelation rate treatment: The preparation conditions for high chelation rate AOS-Zn are the same as in Example 1, 1.1 (chelation rate of 98.3%).

[0060] AOS-Zn was prepared as a 0.3% (w / v) aqueous solution and applied at a rate of 20 kg / mu / time, once uniformly to the leaves using a backpack sprayer at the early tillering stage and the early heading stage. The specific application time for the early tillering stage was 16 days after transplanting, and the specific application time for the early heading stage was 60 days after transplanting. All field trials were conducted with three replicates using a randomized block design, with a plot area of ​​30 m². The number of tillers was recorded 3 days before harvest, and the yield was measured after harvest, with zinc content determined by atomic absorption spectrometry.

[0061] The results are shown in the table below: Table 4. Effects of foliar spraying of AOS-Zn with different chelation rates on zinc content in rice grains

[0062] Example 6: Effect of AOS-Zn application method on zinc accumulation in rice grains AOS-Zn is a high-chelation-rate AOS-Zn prepared by the method in 1.1 of Example 1.

[0063] Three application methods were compared: (1) Soil application: AOS-Zn was prepared into a 0.3% (w / v) aqueous solution and applied once in furrows at a rate of 20 kg / mu / time at the early tillering stage and the early heading stage, respectively; (2) Foliar spraying: AOS-Zn was prepared into a 0.3% (w / v) aqueous solution and applied once evenly to the leaves with a backpack sprayer at a rate of 20 kg / mu / time at the early tillering stage and the early heading stage, respectively; (3) Soil application + foliar spraying: Soil application and foliar spraying were each applied at a rate of 10 kg / mu / time.

[0064] Table 5 Effects of different AOS-Zn application methods on grain zinc content

[0065] As shown in Table 5, foliar spraying significantly increased the zinc content of grains by 32.9% compared to soil application. Although mixed application reached the highest value of 38.1 mg / kg, it was not significantly different from the pure foliar treatment. Considering both the ease of agricultural operation and the input-output ratio, the single foliar spraying scheme is preferred.

[0066] Example 7: Optimization Study of Compound Solution Formulation (1) Screening of gibberellin species Gibberellins (GA3 / GA4 / GA7) were dissolved in anhydrous ethanol at a ratio of 10 mg:1 mL (i.e., 10 mg / mL) to prepare a gibberellin stock solution. Using the 0.3% AOS-Zn base solution from Example 3, an appropriate amount of the gibberellin stock solution was added to the AOS-Zn base solution to achieve a final gibberellin concentration of 10 mg / L. The solution was then applied as described in Example 3, once at a rate of 20 kg / mu / application at the early tillering and early heading stages. The results are shown in Table 6.

[0067] Table 6. Effects of different gibberellin species on rice yield and grain zinc content.

[0068] As shown in Table 6, the GA3 treatment group exhibited the best zinc enrichment effect (38.9 mg / kg), which was 3.5% higher than the control.

[0069] Further, gibberellins were combined in pairs according to the types listed in Table 7. Specifically, using the 0.3% AOS-Zn base solution from Example 3, appropriate amounts of the two aforementioned gibberellin stock solutions were added to the AOS-Zn base solution to achieve a final concentration of 5 mg / L for each gibberellin. Foliar spraying was performed once at the early tillering stage and again at the early heading stage, as in Example 3, at a dosage of 20 kg / mu / time. The results are shown in Table 7.

[0070] Table 7. Effects of combined application of different gibberellin species on rice yield and grain zinc content.

[0071] As shown in Table 7, the combined use of GA3 and GA4 with AOS-Zn resulted in the greatest increase in zinc content in the grains. The combination of GA3+GA4+AOS-Zn resulted in the greatest increase in both zinc content and yield in the grains. Therefore, GA3 and GA4 were selected as the gibberellin components in the compound formulation.

[0072] (2) Optimization of plant growth regulator concentration The effects of three plant growth regulators—GA3 (10, 12, 15 mg / L), GA4 (10, 12, 15 mg / L), and 6-BA (1.5, 2, 2.5 mg / L)—combined with 0.3% AOS-Zn at different final concentrations, applied as a single foliar spray at the early tillering and early heading stages, were systematically investigated. The application rate was 20 kg / mu / time.

[0073] Table 8 Effects of application concentrations of GA3, GA4 and 6-BA on yield, tiller number and grain zinc content.

[0074] Table 8 shows that the best effects of applying GA3 alone at a concentration of 12 mg / L, GA4 alone at a concentration of 12 mg / L, and 6-BA alone at a concentration of 2 mg / L were on increasing yield, tiller number, and grain zinc content.

[0075] (3) Study on optimization of hormone ratio in compound solution Based on the previously determined optimal concentrations of plant growth regulators when applied alone, this experiment focused on investigating the effects of different final concentrations of hormones added to a 0.3% AOS-Zn base solution on rice growth. The volume ratios of each component in each treatment are shown in Table 9, and the effects of each volume ratio of the compound solution on rice yield, tiller number, and grain zinc content are shown in Table 10. Both compound solution 1 and compound solution 2 were applied at a rate of 20 kg / mu / time, once foliar at the early tillering and early heading stages.

[0076] Table 9. Hormone concentrations in different treatments of the compound solution (1 / 2).

[0077]

[0078] Table 10 Effects of each treatment compound solution on rice yield, tiller number, and grain zinc content

[0079] According to the results in Table 10, the optimal composition of compound solution 1 is: compound solution 1 contains 3 g / L AOS-Zn, 5 mg / L GA3 and 1.5 mg / L 6-BA; the optimal composition of compound solution 2 is: compound solution 2 contains 3 g / L AOS-Zn, 5 mg / L GA3 and 5 mg / L GA4.

[0080] (4) Verification test of synergistic effect of compound solution To verify the synergistic effect of compound solution 1 (6-BA+GA3) and compound solution 2 (GA3+GA4) compared to their single-component treatments, the treatments were set up as shown in Table 11. The concentrations of each component in compound solution 1 were the preferred values ​​in (3), namely GA3 5 mg / L and 6-BA 1.5 mg / L; the concentrations of each component in compound solution 2 were the preferred values ​​in (3), namely GA3 5 mg / L and GA4 5 mg / L. Each treatment contained 0.3% AOS-Zn and was foliar sprayed once at the early tillering stage and the early heading stage, with an application rate of 20 kg / mu / time. The concentrations and amounts of 6-BA, GA3, and GA4 were the same as those of the components in compound solutions 1 and 2.

[0081] Table 11 Effects of Compound Solution 1 / 2 and its Components on Zinc Content, Tiller Number, and Yield of Rice Grains

[0082] As shown in Table 11, the zinc content of compound solution 1 (6-BA+GA3) was 8.2% higher than that of GA3 alone; the zinc content of compound solution 2 (GA3+GA4) was 8.5% higher than that of GA4 alone. Both compound solutions 1 and 2 showed significant improvements in grain zinc content, tiller number, and yield compared to their individual components. This indicates a synergistic effect between 6-BA+GA3 and GA3+GA4, and that compound solutions 1 and 2, composed of these components, are significantly more effective in increasing yield and grain zinc content than applying 6-BA, GA3, or GA4 alone.

[0083] Example 8 This embodiment discloses the composition of the special compound agent of the present invention. The special compound agent 1 and 2 are composed of the compound solution 1 and 2 selected in Example 7, plus AOS-Zn and other synergistic and stabilizing substances.

[0084] The specific components and their proportion ranges of compound agents 1 and 2 described in this embodiment are shown in Table 12. The solvent used to dissolve the components in the table is water.

[0085] Table 12 Components and their proportions in Compound Agents 1 and 2

[0086] The optimal values ​​for each component are further selected and shown in the table below: Table 13 Components and their optimal proportions in compound agents 1 and 2

[0087] The preparation method of the compound agent 1 is as follows: (1) Dissolve BR, 6-BA and GA3 completely in anhydrous ethanol according to the proportions in Table 13 to obtain mixture A.

[0088] (2) Dissolve chitosan and potassium silicate in acetic acid solution according to the proportions in Table 13 to obtain mixture B.

[0089] (3) Dissolve AOS-Zn, citric acid, ascorbic acid and Tween-20 in water according to the proportions in Table 13 to obtain mixture C.

[0090] (4) Mix the mixtures A, B and C thoroughly, add water to make up to 1L, and obtain compound agent 1. Store in the dark.

[0091] The preparation method of the compound agent 2 is as follows: (1) Dissolve GA4 and GA3 completely in anhydrous ethanol according to the proportions in Table 13 to obtain mixture I.

[0092] (2) Dissolve chitosan in acetic acid solution according to the proportions in Table 13 to obtain mixture II.

[0093] (3) Dissolve AOS-Zn, citric acid, ascorbic acid and Tween-20 in water according to the proportions in Table 13 to obtain mixture III.

[0094] (4) Mix the mixtures I, II and III thoroughly, add water to make up to 1L, and obtain compound agent 2. Store in the dark.

[0095] Example 9: Study on the synergistic effect of compound preparation application time The compound agent 1 or 2 used in this embodiment is the preferred one in Example 8. It is applied to the leaves once at the early tillering stage and the early heading stage, at a dosage of 20 kg / mu / time.

[0096] The special compound agent of this invention needs to be applied in sequence. To investigate the effects of non-sequential application and the differences between using AOS-Zn alone and applying compound agent 1 and compound agent 2, the following experiment systematically evaluated the effect of the application time of the compound agent on the effect. The treatments were set as follows: Tillering stage treatment: AOS-Zn (control), compound agent 1, compound agent 2; Heading stage treatment: AOS-Zn (control), compound agent 1, compound agent 2; Combination treatment: compound agent 1 / 2 (standard order), compound agent 2 / 1 (reverse order). Table 14 Effects of sequential application of compound agent 1 / 2 at the tillering and heading stages on zinc content, yield, and tiller number in rice.

[0097] Note: Compound Agent 1 / 2 refers to applying Compound Agent 1 during the tillering stage and Compound Agent 2 during the heading stage; Compound Agent 2 / 1 refers to applying Compound Agent 2 during the tillering stage and Compound Agent 1 during the heading stage.

[0098] As shown in Table 14, sequential application (applying compound agent 1 alone during the tillering stage, or applying compound agent 2 alone during the heading stage, or applying compound agent 1 during the tillering stage and compound agent 2 during the heading stage) has a better effect on increasing yield and zinc than non-sequential application (applying compound agent 2 alone during the tillering stage, or applying compound agent 1 alone during the heading stage, or applying compound agent 2 during the tillering stage and compound agent 1 during the heading stage). This indicates that the special compound agent of the present invention needs to be applied at a specific growth stage to achieve the expected effect.

[0099] Furthermore, as shown in Table 14, the yield and zinc increase effect of applying compound agent 1 during the tillering stage and compound agent 2 during the heading stage is significantly stronger than applying compound agent 1 alone during the tillering stage or applying compound agent 2 alone during the heading stage. This indicates that the special compound agent 1 and compound agent 2 of the present invention have a synergistic effect, and the combined application effect is significantly stronger than the single application.

[0100] Example 10 Study on the specific synergistic effect of zinc source A completely randomized block design was used to investigate the synergistic effects of different zinc sources and compounding agents, with seven treatment groups. The zinc sources were AOS-Zn (zinc chelated with seaweed oligosaccharides), EDTA-chelated zinc (zinc chelated with ethylenediaminetetraacetic acid), and zinc sulfate heptahydrate (ZnSO4·7H2O). The treatment setups were as follows: Treatment 1: Water control; Treatments 2-4: Single zinc source (all zinc concentrations were 0.3%); Treatment 5: Standard compounding agent 1 / 2 (containing AOS-Zn); Treatments 6-7: Alternative zinc source compounding agent (compounding agent 1' / 2', without AOS-Zn). In this embodiment, the compound agent 1' / 2' (without AOS-Zn) is prepared without adding AOS-Zn, and the portion of AOS-Zn is made up with water. The concentrations and amounts of EDTA chelated zinc and zinc sulfate heptahydrate are the same as those of AOS-Zn.

[0101] Table 15 Effects of different zinc sources and their combination with compound agents on zinc accumulation, tillering and yield in rice.

[0102] Depend on Figure 3 ( Figure 3 As shown in Table 15 (from right to left, treatments 1-7) and Table 15, AOS-Zn has better effects on increasing yield and zinc content compared to traditional ionic zinc fertilizer heptahydrate zinc sulfate and conventional chelated zinc fertilizer EDTA chelated zinc.

[0103] Furthermore, compound agent 1 / 2 showed significantly better effects on increasing zinc production than treatments 6 and 7, indicating that the main effective component (compound solution) in the special compound agent of this invention only has a synergistic promoting effect with the zinc source (AOS-Zn) in the special compound agent of this invention, and does not have this effect with other zinc sources.

[0104] Furthermore, treatments 6 and 7 showed no significant difference from treatments 3 and 4, indicating that the effective components in the special compound agent of this invention, other than the zinc source, only have a significant synergistic effect with AOS-Zn. Replacing AOS-Zn in compound agent 1 / 2 with other zinc sources cannot achieve the desired effect of increasing production and zinc content. AOS-Zn + compound agent 1 / 2 is the best combination for increasing production and zinc content.

[0105] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a zinc-chelated phoeyan oligosaccharide, characterized by, Comprising the following steps: (1) mixing seaweed oligosaccharide aqueous solution with zinc nitrate hexahydrate aqueous solution, adjusting pH to 7, stirring at 40℃ for 15 minutes, adjusting pH to 5, stirring at 55℃ for 45 minutes, adjusting pH to 6.5, stirring at 70℃ for 45 minutes, lowering temperature to 0℃ to terminate the reaction, obtaining seaweed oligosaccharide chelated zinc crude solution; (2) adjusting pH to 6, adding sodium bicarbonate to the seaweed oligosaccharide chelated zinc crude solution to precipitate unchelated zinc, centrifuging, collecting supernatant; (3) repeating step (2) until no precipitation occurs, adjusting pH to 6.5 with acid, concentrating, drying to obtain purified seaweed oligosaccharide chelated zinc.

2. The preparation method according to claim 1, characterized in that, the molar ratio of seaweed oligosaccharide to zinc nitrate hexahydrate in step (1) is 1-3:

1.

3. The preparation method according to claim 1, characterized in that, The amount of sodium bicarbonate added in step (2) is based on HCO3 2- Zn 2+ A molar ratio of 2 to 3:1 was added, in which Zn 2+ Zn in zinc nitrate hexahydrate 2+ The amount of substance.

4. A zinc chelated with a seaweed oligosaccharide, characterized in that, obtained by the preparation method according to any one of claims 1-3.

5. The use of seaweed oligosaccharide chelated zinc according to claim 4 in regulating plant growth.

6. The use of seaweed oligosaccharide chelated zinc according to claim 4 in preparing plant growth regulators.

7. A plant growth regulator, characterized by, containing seaweed oligosaccharide chelated zinc according to claim 4.

8. The plant growth regulator according to claim 7, characterized in that, further containing 5mg / L of GA3 and 5mg / L of GA4.

9. The plant growth regulator according to claim 7, characterized by further containing 1.5mg / L of 6-BA and 5mg / L of GA3.

10. A method of regulating the growth of a plant, characterized by, Comprising the following steps: applying the plant growth regulator according to claim 9 to the leaves at a dosage of 20kg / acre / time at the early tillering stage, and applying the plant growth regulator according to claim 8 to the leaves at a dosage of 20kg / acre / time at the early heading stage; said regulating plant growth comprises at least one of increasing rice yield, increasing rice tiller number and increasing rice grain zinc content.

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