Application of hydroxypropyl chitosan oligosaccharide in preparation of plant growth regulator

Abstract

The invention provides application of hydroxypropyl chitosan oligosaccharide in preparation of a plant growth regulator, and belongs to the technical field of plant growth. The hydroxypropyl chitosan oligosaccharide is used as a raw material to prepare the plant growth regulator, new application of the hydroxypropyl chitosan oligosaccharide is provided, the seedling height of plants can be effectively increased, the root length can be effectively increased, the number and / or weight of root nodules can be effectively increased, the number of the root nodules of the plants and / or the activity of nitrogenase can be effectively increased, and the yield of the plants is increased. According to the present invention, the activity of glutathione reductase (GR) and / or glutathione transferase (GST) is improved so as to increase the reduced glutathione content, enhance the oxidation resistance of plants and / or enhance the salt resistance of crops, and after the compound fertilizer is compounded with the calcium-magnesium element fertilizer, the use amount of the compound fertilizer is reduced so as to provide effects of application reducing and effect increasing. The method for preparing the plant growth regulator is simple and easy to implement, environmentally friendly and convenient to popularize and apply.

Description

Technical Field

[0001] The invention belongs to the technical field of plant growth, and particularly relates to the application of hydroxypropyl chitosan oligosaccharide in the preparation of a plant growth regulator. Background Art

[0002] Salt stress is the most common adverse stress in plant growth. Salt stress affects the ion balance, osmotic pressure, absorption and metabolism of nutrient elements in plant cells, which in turn seriously affects the growth and development of plants. China has a vast area of ​​saline soils with a wide variety of types. Currently, most modern saline soils are cultivated agricultural areas, most of which are important grain, cotton and oil crop production bases in my country, but the crop yields are low.

[0003] Chitosan / oligosaccharide is a natural active substance. By modifying chitosan / oligosaccharide molecules and obtaining its derivatives, its application effect and application range can be broadened. At present, studies have prepared chitosan oligosaccharide Schiff base derivatives that can improve plant resistance to tobacco mosaic virus; chitosan quaternary ammonium salts can improve the antibacterial activity of plants against plant pathogenic fungi such as peanut cercospora, Rhizoctonia solani, apple ring rot fungus, and cocoa thorn spores. However, there is no research on the role of chitosan / oligosaccharides in improving plant salt resistance. Summary of the invention

[0004] The purpose of the present invention is to provide an application of hydroxypropyl chitosan oligosaccharide in the preparation of a plant growth regulator, and to use the plant growth regulator containing hydroxypropyl chitosan oligosaccharide to improve the salt stress resistance of plants.

[0005] The present invention provides the use of hydroxypropyl chitosan oligosaccharide in the preparation of a plant growth regulator having any one or more of the effects shown in ① to ④:

[0006] ① Promote plant growth;

[0007] ② Improve the nitrogen fixation ability of plants;

[0008] ③ Improve the salt resistance of plants;

[0009] ④Reduce the amount of plant fertilizer applied.

[0010] The invention also provides a plant growth regulator, and the raw materials used for preparing the same include hydroxypropyl chitosan oligosaccharide and auxiliary materials.

[0011] Preferably, the auxiliary material includes one or more of calcium, magnesium and a surfactant.

[0012] Preferably, the mass fraction of hydroxypropyl chitosan oligosaccharide in the plant growth regulator is 0.5 to 2 parts; the mass fraction of calcium in the plant growth regulator is 1 to 65 parts; the mass fraction of magnesium in the plant growth regulator is 1 to 35 parts; and the mass fraction of surfactant in the plant growth regulator is 1 to 20 parts.

[0013] Preferably, the calcium comprises calcium nitrate and / or chelated calcium; and the magnesium comprises magnesium nitrate and / or chelated magnesium.

[0014] Preferably, the molecular weight of the hydroxypropyl chitosan oligosaccharide is 500-2000 Da.

[0015] The present invention also provides a method for preparing the plant growth regulator described in the above technical solution, comprising mixing the raw materials for preparation with water to prepare the plant salt resistance regulator.

[0016] The present invention also provides a method for using the plant growth regulator described in the above technical solution or the plant growth regulator prepared by the preparation method described in the above technical solution, including soaking plant seeds, spraying on plant leaves and / or irrigating roots.

[0017] Preferably, the plant growth regulator is further mixed with water before use, and the volume ratio of the plant salt resistance regulator to water is 1:(250-1000).

[0018] The present invention also provides the plant growth regulator described in the above technical solution or the plant growth regulator prepared by the preparation method described in the above technical solution, which has the effect of any one of ① to ⑦:

[0019] ①Increase the height of plant seedlings;

[0020] ②Increase root length;

[0021] ③Increase the number of nodules;

[0022] ④Increase nodule weight;

[0023] ⑤ Enhance the nitrogen fixation ability of plants;

[0024] ⑥ Enhance the antioxidant capacity of plants;

[0025] ⑦ Improve the salt resistance of plants.

[0026] The present invention provides a new application of hydroxypropyl chitosan oligosaccharide, which can be used to prepare a plant growth regulator having any one or more of the following effects: promoting plant growth, improving plant nitrogen fixation ability, improving plant salt resistance activity, and reducing plant fertilizer application amount, thereby improving fertilizer utilization rate, thereby reducing fertilizer and other chemical inputs and improving plant quality and economic benefits.

[0027] The present invention uses hydroxypropyl chitosan oligosaccharide as a raw material to prepare a plant growth regulator, which can effectively promote plants to increase seedling height, increase root length, increase the number and weight of nodules, increase the number of plant nodules and nitrogenase activity, increase the activity of glutathione reductase (GR) and glutathione transferase (GST) to increase the content of reduced glutathione, enhance plant antioxidant capacity and enhance the salt resistance of crops. In addition, the method for preparing the plant growth regulator of the present invention is simple and easy to implement, and is convenient for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A comparison diagram of the effects of different chitosan oligosaccharide derivatives provided by the present invention on soybean seedlings under salt stress;

[0030] Figure 2 A comparison diagram of the effects of different treatments provided by the present invention on soybean seedlings under salt stress;

[0031] Figure 3 A comparison chart of nitrogenase activity of soybean nodules in different treatment groups under salt stress provided by the present invention;

[0032] Figure 4 A comparison chart of GSH and GSSG contents in soybean seedlings of different treatment groups under salt stress provided by the present invention;

[0033] Figure 5 This is a comparison chart of GR and GST activities of soybean seedlings in different treatment groups under salt stress provided by the present invention. DETAILED DESCRIPTION

[0034] The present invention provides the use of hydroxypropyl chitosan oligosaccharide in the preparation of a plant growth regulator having any one or more of the effects shown in ① to ④:

[0035] ① Promote plant growth;

[0036] ② Improve the nitrogen fixation ability of plants;

[0037] ③ Improve the salt resistance of plants;

[0038] ④Reduce the amount of plant fertilizer applied.

[0039] The present invention also provides a plant growth regulator, the raw materials for preparation include hydroxypropyl chitosan oligosaccharide and auxiliary materials. In the present invention, the hydroxypropyl chitosan oligosaccharide is preferably purchased from Qingdao Hehai Biotechnology Co., Ltd. In the present invention, the auxiliary materials preferably include one or more of calcium, magnesium and surfactants.

[0040] In the present invention, the mass fraction of hydroxypropyl chitosan oligosaccharide in the plant growth regulator is preferably 0.5 to 2 parts, and the mass concentration is preferably 0.5 to 2 g / L. When the plant growth regulator is used for soybean seed germination, the most suitable fraction of hydroxypropyl chitosan oligosaccharide in the plant growth regulator is more preferably 0.5 parts, and the most suitable concentration is more preferably 0.5 g / L. When the plant growth regulator is used for soybean seedling treatment, the most suitable fraction of hydroxypropyl chitosan oligosaccharide in the plant growth regulator is more preferably 1 part, and the most suitable concentration is more preferably 1 g / L.

[0041] In the present invention, the mass fraction of calcium in the plant growth regulator is preferably 1 to 65 parts, more preferably 65 parts, and the mass concentration is preferably 1 to 65 g / L, more preferably 65 g / L. In the present invention, the mass fraction of magnesium in the plant growth regulator is preferably 1 to 35 parts, more preferably 35 parts, and the mass concentration is preferably 1 to 35 g / L, more preferably 35 g / L. In the present invention, the mass fraction of surfactant in the plant growth regulator is 1 to 20 parts, more preferably 1 part, and the mass concentration is preferably 1 to 20 g / L, more preferably 1 g / L.

[0042] In the present invention, the calcium preferably includes calcium nitrate and / or chelated calcium. In the present invention, the magnesium preferably includes magnesium nitrate and / or chelated magnesium. Studies have shown that calcium plays an inestimable role in the growth and development of plants. Calcium can stabilize cell membranes and cell walls, participate in second messenger transmission, regulate osmotic effects, have enzymatic effects, etc., and calcium also plays an important role in controlling the development of cells and tissues. Increasing the application of a certain amount of calcium ions can promote the growth and development of plant roots and enhance stress resistance. Magnesium is an important component of chlorophyll and is an essential nutrient for plant growth and development. Appropriate application of magnesium fertilizer can promote the growth and development of plants, improve their botanical traits, and increase the chlorophyll and carotenoid content of leaves.

[0043] In the present invention, the molecular weight of the hydroxypropyl chitosan oligosaccharide is preferably 500-2000Da, more preferably 1000Da.

[0044] The plant growth regulator of the present invention can effectively promote plants to increase seedling height, increase root length, increase the number and weight of nodules, increase the number of plant nodules and nitrogenase activity, increase the activity of glutathione reductase (GR) and glutathione transferase (GST) to increase the content of reduced glutathione, enhance the antioxidant capacity of plants and enhance the salt resistance of crops.

[0045] The present invention also provides a method for preparing the plant growth regulator described in the above technical solution, comprising mixing the raw materials for preparation with water to prepare the plant salt resistance regulator. The components are simple, the raw materials are easily available, and the cost is low.

[0046] The present invention also provides a method for using the plant growth regulator described in the above technical solution or the plant growth regulator prepared by the preparation method described in the above technical solution, including soaking plant seeds, spraying on the leaves of plants and / or irrigating the roots. The method is simple and easy to implement, and is convenient for promotion and application.

[0047] In the present invention, the plant growth regulator is further mixed with water before use, and the volume ratio of the plant salt resistance regulator to water is preferably 1:(250-1000), more preferably 1:(500-800).

[0048] The present invention also provides the plant growth regulator described in the above technical solution or the plant growth regulator prepared by the preparation method described in the above technical solution, which has the effect of any one of ① to ⑦:

[0049] ①Increase the height of plant seedlings;

[0050] ②Increase root length;

[0051] ③Increase the number of nodules;

[0052] ④Increase nodule weight;

[0053] ⑤ Enhance the nitrogen fixation ability of plants;

[0054] ⑥ Enhance the antioxidant capacity of plants;

[0055] ⑦ Improve the salt resistance of plants.

[0056] To further illustrate the present invention, the method and application of hydroxypropyl chitosan oligosaccharide in preparing plant growth regulators provided by the present invention are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the scope of protection of the present invention.

[0057] Example 1

[0058] 500 mg of hydroxypropyl chitosan oligosaccharide with a molecular weight of 1000 Da was weighed and dissolved in 800 mL of distilled water, and then 1 g of surfactant Tween-80 was added and stirred evenly, and finally the volume was adjusted to 1 L with distilled water.

[0059] Example 2

[0060] 1000 mg of hydroxypropyl chitosan oligosaccharide with a molecular weight of 500 Da was weighed and dissolved in 800 mL of distilled water, and then 10 g of surfactant Tween-80 was added and stirred evenly, and finally the volume was adjusted to 1 L with distilled water.

[0061] Example 3

[0062] 2000 mg of hydroxypropyl chitosan oligosaccharide with a molecular weight of 2000 Da was weighed and dissolved in 800 mL of distilled water, and then 20 g of surfactant Tween-80 was added and stirred evenly, and finally the volume was adjusted to 1 L with distilled water.

[0063] Comparative Example 1

[0064] Compared with Example 2, the difference is that the hydroxypropyl chitosan oligosaccharide is replaced by carboxymethyl chitosan oligosaccharide, and the other conditions are the same as those in Example 2.

[0065] Comparative Example 2

[0066] Compared with Example 2, the difference is that the hydroxypropyl chitosan oligosaccharide is replaced by chitosan oligosaccharide quaternary ammonium salt, and the other conditions are the same as those in Example 2.

[0067] Comparative Example 3

[0068] Compared with Example 2, the difference is that the hydroxypropyl chitosan oligosaccharide is replaced by chitosan oligosaccharide, and the other conditions are the same as those in Example 2.

[0069] Application Example 1

[0070] Select uniform, round and full soybean seeds. Disinfect the soybean seeds with 1% sodium hypochlorite solution for 10 minutes, rinse with distilled water, and then plant them in the seedling tray. Use a 15cm flower pot filled with 200g of vermiculite, sow soybeans evenly (6 seeds per pot) after natural water absorption, and then cover with 1cm of soil. Place 3 pots in each treatment and culture them in an artificial climate incubator. The conditions of the light incubator are set as follows: temperature 25 / 20℃ (day / night), light intensity 800μmol / m / s, light cycle 14 / l0h (day / night), and relative humidity 65±5%.

[0071] After the soybeans grew into the first group of three compound leaves, 200 mL of 150 mmol / L NaCl solution was naturally infiltrated into the soil from the bottom of each pot for salt stress, and the clean water group was used as the control (CK). After 24 hours of salt stress treatment, the chitosan oligosaccharide derivatives or chitosan oligosaccharide solutions described in Example 2, Comparative Example 1, Comparative Example 2 and Comparative Example 3 were diluted with water, and the CK and NaCl groups were sprayed with clean water, with the leaf surface covered with water droplets and not falling naturally as the benchmark. Each treatment was sprayed with 50 mL. The effects of different chitosan oligosaccharide derivatives on soybean seedlings under salt stress are compared as shown in the figure below. Figure 1 Sampling and determination of various physiological indices were performed on the 7th day after treatment.

[0072] Measurement items and methods:

[0073] On the 7th day after treatment, the length of the plant from the pot surface to the top was measured with a ruler.

[0074] The aboveground leaves were randomly sampled, quickly frozen with liquid nitrogen and stored in a -80°C refrigerator for the determination of physiological indicators.

[0075] The whole soybean seedling was taken out of the pot, rinsed with distilled water, and then excess water was absorbed through filter paper, and the root length and number of nodules were measured.

[0076] Table 1 Effects of different chitosan oligosaccharide derivatives on agronomic traits of soybean seedlings under salt stress

[0077] Plant height(cm) Root length (cm) Nodule number Nodule weight (mg) CK 45.0±1.6a 17.2±1.2a 17.9±2.3b 116.1±5.3c NaCl 40.5±1.4b 14.4±1.3b 8.1±1.7c 47.2±2.2d COSS 40.8±2.9b 17.8±2.2a 19.3±1.8b 130.2±4.5b COSQ 44.3±3.0a 17.4±1.4a 22.0±2.4a 147.5±6.3a COSJ 40.9±4.9b 17.6±2.5a 17.2±2.1b 121.5±2.8c COS 43.5±1.7a 17.7±1.6a 18.4±1.4b 132.9±3.5b

[0078] Note: CK, control group; NaCl, salt stress group; COSS, group treated with carboxymethyl chitosan oligosaccharide under salt stress; COSQ, group treated with hydroxypropyl chitosan oligosaccharide under salt stress; COSJ, group treated with quaternary ammonium chitosan oligosaccharide under salt stress; COS: group treated with chitosan oligosaccharide under salt stress.

[0079] Depend on Figure 1 As shown in Table 1, under NaCl stress, the growth of soybean seedlings was inhibited, the seedling height decreased, and the root length was significantly reduced; spraying different chitosan oligosaccharide derivatives can alleviate the inhibitory effect of NaCl stress on the growth of soybean seedlings to varying degrees. For seedling height, spraying hydroxypropyl chitosan oligosaccharide and chitosan oligosaccharide can significantly increase the height of soybean seedlings to the level of the control group; while carboxymethyl chitosan oligosaccharide and chitosan oligosaccharide quaternary ammonium salt did not significantly increase the height of soybean seedlings. For root length, different chitosan oligosaccharide derivatives can increase soybean root length, but there is no significant difference between the groups. Different chitosan oligosaccharide derivatives have a significant effect on the number and weight of soybean nodules. Among them, hydroxypropyl chitosan oligosaccharide can significantly increase the number and weight of nodules of soybean seedlings under salt stress, enhance the nitrogen fixation ability of soybeans, and thus improve its salt resistance activity.

[0080] Application Example 2

[0081] Based on Example 1, hydroxypropyl chitosan oligosaccharide was selected as the core material, and calcium and magnesium fertilizers of different concentrations and different proportions were added to form a total of 6 treatment groups:

[0082] CK was the blank control group; NaCl was the salt stress group;

[0083] T1 was the hydroxypropyl chitosan oligosaccharide treatment group (1 g / L hydroxypropyl chitosan oligosaccharide, 1 g surfactant, prepared into 1 L solution);

[0084] T2 is composition 1 (1 g / L hydroxypropyl chitosan oligosaccharide, 65 g / L calcium, 35 g / L magnesium, 1 g surfactant, prepared into 1 L solution, diluted 250 times before use);

[0085] T3 is composition 3 (mixture of 1 g / L hydroxypropyl chitosan oligosaccharide, 65 g / L calcium, and 35 g / L magnesium, 1 g surfactant, prepared into 1 L solution, diluted 500 times before use);

[0086] T4 is composition 3 (mixture of 1 g / L hydroxypropyl chitosan oligosaccharide, 65 g / L calcium, and 35 g / L magnesium, 1 g surfactant, prepared into 1 L solution, diluted 1000 times before use);

[0087] T5 is a group where calcium and magnesium are administered alone (calcium 65 g / L and magnesium 35 g / L are mixed with 1 g of surfactant, prepared into 1 L solution, diluted 250 times before use).

[0088] Select uniform, round and full soybean seeds. Disinfect the soybean seeds with 1% sodium hypochlorite solution for 10 minutes, rinse with distilled water, and then plant them in the seedling tray. Use a 15cm flower pot filled with 200g of vermiculite, sow soybeans evenly (6 seeds per pot) after natural water absorption, and then cover with 1cm of soil. Place 3 pots in each treatment and culture them in an artificial climate incubator. The conditions of the light incubator are set as follows: temperature 25 / 20℃ (day / night), light intensity 800μmol / m / s, light cycle 14 / l0h (day / night), and relative humidity 65±5%.

[0089] When the soybean seedlings grew the first set of three compound leaves, 200 mL of 150 mmol / L NaCl solution was naturally infiltrated into the soil from the bottom of each pot for salt stress, and the water group was used as the control (CK). After 24 hours of salt stress treatment, the soybean leaves were sprayed with the above treatment groups, and the CK and NaCl groups were sprayed with water. The leaf surface was covered with water droplets and would not fall naturally. Each treatment was sprayed with 50 mL. The comparison of the effects of different treatments on soybean seedlings under salt stress is shown in the figure below. Figure 2 As shown. Sampling and various physiological indices were measured on the 7th day after treatment. Agronomic traits included seedling height, root length, seedling dry weight, root dry weight, and number of nodules. The contents of reduced glutathione (GSH) and oxidized glutathione (GSSG), and the activities of glutathione reductase (GR) and glutathione transferase (GST) were determined using Nanjing Jiancheng kits.

[0090] Table 2 Effects of different treatments on agronomic traits of soybean seedlings under salt stress

[0091]

[0092]

[0093] Depend on Figure 2As can be seen from Table 2, under salt stress, the growth of soybean seedlings was inhibited, and the seedling height and root length were lower than those of the control group, but there was no significant difference; however, the seedling dry weight, root dry weight, and number of nodules were significantly lower than those of the control group. After treatment with different chitosan oligosaccharide derivatives, the growth of soybean seedlings under salt stress was alleviated. Although there were no significant differences in seedling height and root length after treatment from T1 to T5. However, there were significant differences between different treatment groups and the salt stress group in terms of dry weight and number of nodules. Compared with the salt stress group, the seedling dry weight of T1 to T5 treatments increased by 23.1%, 35.9%, 38.5%, 28.2% and 17.9%, respectively; among them, the T2 and T3 groups were significantly better than the T1 and T5 groups. Compared with the salt stress group, the root dry weight increased by 37.7%, 56.5%, 62.3%, 52.2% and 23.2%, respectively, among which the T2, T3 and T4 groups were significantly better than the T5 calcium and magnesium fertilizer application group. Different treatments also promoted soybean nodule traits under salt stress. Compared with the salt stress group, the number of nodules in T1 to T5 treatments increased by 105.1%, 130.6%, 135.0%, 128.0% and 94.3%, respectively. Among them, T2, T3 and T4 groups were significantly better than T5 calcium magnesium fertilizer alone application group. The above results show that different treatments can increase the accumulation of dry matter in soybean seedlings under salt stress, increase the number and quality of soybean nodules, and improve nitrogen fixation ability. Among them, the combination of hydroxypropyl chitosan oligosaccharide with calcium and magnesium can significantly improve the salt resistance and nitrogen fixation ability of soybeans, which is better than the use of hydroxypropyl chitosan oligosaccharide or calcium magnesium compound fertilizer alone. In the T3 group, the concentration of hydroxypropyl chitosan oligosaccharide was diluted 500 times and then applied in combination with calcium and magnesium fertilizers. The effect was better than that of the T1 group (i.e., the group where hydroxypropyl chitosan oligosaccharide was applied alone) and the T5 group (i.e., the group where calcium and magnesium fertilizers were used alone). This shows that the combination of hydroxypropyl chitosan oligosaccharide and calcium and magnesium not only exerted the stress-resistant and growth-promoting effect of hydroxypropyl chitosan oligosaccharide, but also reduced the amount of compound fertilizer used after the use of compound calcium and magnesium fertilizers, thereby reducing the amount of fertilizer used and increasing efficiency.

[0094] The content of reduced glutathione (GSH) and oxidized glutathione (GSSG) in soybean seedlings, and the activities of glutathione reductase (GR) and glutathione transferase (GST) were determined according to the kit method. Figure 3As shown. It can be seen that under salt stress, the nitrogenase activity of soybean nodules was significantly reduced, and the nitrogenase activity of soybean nodules treated with different chitosan oligosaccharide derivatives was significantly improved. T1 and T5 were increased by 24.7% and 24.8% respectively compared with the salt stress group, which was significantly lower than the control group; T4 treatment group was increased by 47.1% compared with the salt stress group, which was equivalent to the level of the control group; T2 and T3 were increased by 54.5% and 56.5% respectively compared with the salt stress group, which was significantly higher than the control group and the salt stress group. It can be seen that the plant salt resistance regulator prepared by the present invention can effectively reduce the effect of salt stress on soybean nodules, increase the nitrogenase activity of nodules, and thus improve the growth of soybeans under salt stress; and the synergistic effect is better than the application of hydroxypropyl chitosan oligosaccharide or calcium magnesium compound fertilizer alone.

[0095] Comparison of GSH and GSSG contents in soybean seedlings under different treatment groups under salt stress Figure 4 As shown in the figure, the comparison of GR and GST activities in soybean seedlings of different treatment groups under salt stress is shown in Figure 5 As shown. Figure 4 and Figure 5 It can be seen that under salt stress, the content of reduced glutathione (GSH) in soybean seedlings significantly decreased by 32.7%, while the content of oxidized glutathione (GSSG) significantly increased by 41.6%, indicating that soybean seedlings suffered oxidative stress under salt stress. The content of soybean GSSH decreased after different treatments, among which the effect of hydroxypropyl chitosan oligosaccharide combined with calcium and magnesium fertilizer (T2, 3, 4) was significantly better than the use of either alone (T1, T5).

[0096] Under the stimulation of salt stress, the GR and GST activities of soybean seedlings increased; different treatments further enhanced the GR and GST activities of soybean seedlings. The combined use of hydroxypropyl chitosan oligosaccharide and calcium and magnesium significantly increased the reduced glutathione content of soybean seedlings under salt stress by enhancing the GR and GST activities of soybeans, promoted the glutathione cycle, and enhanced the antioxidant capacity of soybeans. The combined use effectively reduced the use of calcium and magnesium nitrates, reduced production costs, reduced environmental pollution, and increased the utilization rate of calcium and magnesium fertilizers, comprehensively improved the salt resistance of soybean seedlings, and at the same time improved the quality and yield of soybeans.

[0097] In summary, the plant growth-promoting and salt-resistant preparation containing hydroxypropyl chitosan oligosaccharide and calcium and magnesium elements of the present invention can improve the salt-resistant activity of soybean by promoting glutathione circulation and enhancing the antioxidant capacity of soybean; and the combined use can effectively reduce the usage of calcium, magnesium and nitrate, reduce production costs, reduce environmental pollution, enhance the comprehensive resistance of plants to salt stress, and significantly increase the output value and economic benefits of soybean.

[0098] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the technical solutions described in the aforementioned embodiments are modified, or some or all of the technical features therein are replaced by equivalents, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. Application of hydroxypropyl chitosan oligosaccharide in the preparation of plant growth regulators having any one or more of the effects as shown in ① to ④: ① Promote plant growth; ② Improve the nitrogen fixation ability of plants; ③ Improve the salt resistance of plants; ④Reduce the amount of plant fertilizer applied.

2. A plant growth regulator, characterized in that The raw materials used for preparation include hydroxypropyl chitosan oligosaccharide and auxiliary materials.

3. The plant growth regulator according to claim 2, characterized in that The auxiliary materials include one or more of calcium, magnesium and surfactants.

4. The plant growth regulator according to claim 3, characterized in that The mass fraction of hydroxypropyl chitosan oligosaccharide in the plant growth regulator is 0.5 to 2 parts; the mass fraction of calcium in the plant growth regulator is 1 to 65 parts; the mass fraction of magnesium in the plant growth regulator is 1 to 35 parts; and the mass fraction of surfactant in the plant growth regulator is 1 to 20 parts.

5. The plant growth regulator according to claim 3, characterized in that The calcium includes calcium nitrate and / or chelated calcium; the magnesium includes magnesium nitrate and / or chelated magnesium.

6. The plant growth regulator according to claim 2, characterized in that The molecular weight of the hydroxypropyl chitosan oligosaccharide is 500-2000Da.

7. A method for preparing the plant growth regulator according to any one of claims 2 to 6, comprising mixing the raw materials for preparation with water to prepare the plant growth regulator.

8. A method for using the plant growth regulator according to any one of claims 2 to 6 or the plant growth regulator prepared by the preparation method according to claim 7, comprising soaking plant seeds, spraying on plant leaves and / or irrigating roots.

9. The method of use according to claim 8, characterized in that: The plant growth regulator is further mixed with water before use, and the volume ratio of the plant salt resistance regulator to water is 1: (250-1000).

10. Use of the plant growth regulator according to any one of claims 2 to 6 or the plant growth regulator prepared by the preparation method according to claim 7 in any one of the effects ① to ⑦: ①Increase the height of plant seedlings; ②Increase root length; ③Increase the number of nodules; ④Increase nodule weight; ⑤ Enhance the nitrogen fixation ability of plants; ⑥ Enhance the antioxidant capacity of plants; ⑦ Improve the salt resistance of plants.

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