Application of water-soluble inorganic sulfide in improvement of plant salt stress resistance and / or improvement of saline-alkali soil

Abstract

The invention provides application of water-soluble inorganic sulfide in improvement of plant salt stress resistance and / or improvement of saline-alkali soil, relates to the technical field of agriculture, and provides application of water-soluble inorganic sulfide in improvement of plant salt stress resistance and / or improvement of saline-alkali soil. The water-soluble inorganic sulfide is selected from at least one of potassium sulfide, ammonium sulfide and calcium polysulfide, the potassium sulfide, the ammonium sulfide and the calcium polysulfide can effectively improve the germination ability of plant seeds under salt stress, and the calcium polysulfide can effectively improve the plant antioxidant system activity and the plant photosynthesis efficiency; the survival rate and the growth performance of the plants under salt stress are effectively improved; the water-soluble inorganic sulfide solution can effectively reduce the EC value of the saline-alkali soil, so that the germination rate of plant seeds in the saline-alkali soil is effectively increased, and the saline-alkali soil is effectively improved. Therefore, the application provided by the invention is of great significance in fully utilizing saline-alkali land resources and improving the crop yield.

Description

Technical Field

[0001] This invention relates to the field of agricultural technology, and in particular to the application of water-soluble inorganic sulfides in improving plant salt stress resistance and / or improving saline-alkali land. Background Technology

[0002] Saline-alkali land is mainly concentrated in the coastal plains of major continents, such as the eastern coast of China, the Mekong Delta in Southeast Asia, the North Sea coast of Europe, and the Gulf Coast of the United States, accounting for more than 30% of the global saline-alkali land area. In my country, coastal saline-alkali land is the largest type. In terms of distribution, my country's coastal saline-alkali land is mainly concentrated in the eastern coastal areas, including the Bohai Bay coast, the Yellow River Delta, the Yangtze River Delta, the Pearl River Delta, and the coastal areas of northern Jiangsu. Statistics show that its total area exceeds 2 million hectares, far exceeding the area of ​​a single type of inland saline-alkali land (such as saline-alkali land in the arid and semi-arid regions of Northwest China). The formation of this type of saline-alkali land is closely related to the marine environment, mainly composed of chloride salts, with high soil salinity and a tendency to compact. However, because it is distributed in economically developed coastal areas and serves as an important reserve land resource, it has become one of the key areas for land resource development in my country in recent years through improvements and utilization projects such as the "Bohai Granary". Existing problems: Saline-alkali land leads to a 30-80% decrease in seed germination rate and low seedling survival rate. Existing salt-tolerant treatment technologies (such as hormone immersion and genetic modification) are either costly or complex to operate. Summary of the Invention

[0003] To address the aforementioned problems in the prior art, the present invention aims to provide the application of water-soluble inorganic sulfides in improving plant salt stress resistance and / or saline-alkali land improvement. This can significantly enhance the ability of plants to withstand salt and alkali stress and also serve as a soil conditioner to effectively reduce the soluble salt content and salinity in the soil, thereby solving the problems of poor plant growth and low yield in moderately to severely saline-alkali environments in the prior art.

[0004] A first aspect of the present invention provides the application of water-soluble inorganic sulfides in improving plant salt stress resistance and / or saline-alkali land improvement, characterized in that the water-soluble inorganic sulfides are selected from potassium sulfide (K2S), ammonium sulfide ((NH4)2S), and calcium polysulfide (CaS). x At least one of (x = 2 - 8).

[0005] Preferably, the plants include, but are not limited to, food crops, vegetables, flowers, and fruit trees.

[0006] More preferably, the plant is at least one of rapeseed, corn, and sorghum.

[0007] A second aspect of the present invention provides a method for improving the salt stress resistance of plants, comprising: applying a water-soluble inorganic sulfide to at least one of the following: (1) Plants subjected to salt stress; (2) Plants at risk of salt stress; (3) The growth environment of plants under salt stress; (4) Plant growth environments with salt stress risk; The water-soluble inorganic sulfides are selected from potassium sulfide (K2S), ammonium sulfide ((NH4)2S), and calcium polysulfide (CaS). x At least one of (x = 2 - 8).

[0008] Preferably, the water-soluble inorganic sulfide is calcium polysulfide.

[0009] Preferably, the application method includes at least one of soil irrigation, foliar spraying, and seed treatment.

[0010] Preferably, the application method is soil irrigation, and the amount of potassium sulfide applied each time during soil irrigation is 10~25 kg / mu; More preferably, the potassium sulfide is applied to the soil in the form of a potassium sulfide solution, wherein the concentration of potassium sulfide in the potassium sulfide solution is 50-250 mg / L, preferably 80-120 mg / L, and more preferably 100 mg / L.

[0011] Preferably, the application method is soil irrigation, and the amount of ammonium sulfide applied each time during soil irrigation is 10~20 kg / mu; More preferably, the ammonium sulfide is irrigated into the soil in the form of an ammonium sulfide solution, wherein the concentration of ammonium sulfide in the ammonium sulfide solution is 10~100 mg / L, preferably 40~60 mg / L, and more preferably 50 mg / L.

[0012] Preferably, the application method is soil irrigation, and the amount of calcium polysulfide applied each time during soil irrigation is 10~25 kg / mu; More preferably, the calcium polysulfide solution is applied to the soil in the form of a calcium polysulfide-containing solution, wherein the concentration of the calcium polysulfide solution in the calcium polysulfide-containing solution is 50~250 mg / L, preferably 80~120 mg / L, and more preferably 100 mg / L.

[0013] In this invention, potassium sulfide is irrigated into the soil in the form of a potassium sulfide solution, with the concentration of potassium sulfide in the solution controlled at 80-120 mg / L; ammonium sulfide is irrigated into the soil in the form of an ammonium sulfide solution, with the concentration of ammonium sulfide in the solution controlled at 40-60 mg / L; and calcium polysulfide is irrigated into the soil in the form of a calcium polysulfide solution, with the concentration of calcium polysulfide in the solution controlled at 80-120 mg / L. Potassium sulfide, ammonium sulfide, and calcium polysulfide solutions at specific concentrations can further and effectively improve the germination ability of plant seeds under salt stress. Among them, calcium polysulfide can further and effectively improve the activity of plant antioxidant systems and the efficiency of plant photosynthesis, thereby further and effectively improving the survival rate and growth performance of plants under salt stress. At the same time, water-soluble inorganic sulfide solutions at specific concentrations can further and effectively reduce the EC value (Electrical Conductivity) of saline-alkali soil, thereby further and effectively improving the germination rate of plant seeds in saline-alkali soil, thus achieving effective improvement of saline-alkali soil.

[0014] Preferably, the water-soluble inorganic sulfide is applied when the seeds are planted in the growth substrate, and then applied every 2 to 4 days thereafter. More preferably, the water-soluble inorganic sulfide is applied when the seeds are planted in the growth substrate, and then applied every 3 days thereafter.

[0015] Preferably, the plant growth environment under salt stress includes saline-alkali land with a soil salinity of 0.3wt%-2.0wt%.

[0016] A third aspect of the present invention provides a composition for improving the salt stress resistance of plants, comprising a water-soluble inorganic sulfide selected from at least one of potassium sulfide, ammonium sulfide, and calcium polysulfide; More preferably, the composition comprises ammonium sulfide, potassium sulfide, and calcium polysulfide; More preferably, the composition includes fertilizer, soil conditioner, or plant growth regulator.

[0017] Compared with the prior art, the beneficial technical effects of the present invention are as follows: Chemical modification is widely used due to its simplicity and rapid effectiveness. Ammonium sulfide, potassium sulfide, and calcium polysulfide, as typical inorganic water-soluble inorganic sulfides, have shown significant research value and application potential in industrial production, environmental protection, and new energy fields. Ammonium sulfide ((NH4)2S), as a highly efficient heavy metal precipitant, releases sulfur dioxide (S2S) through chemical modification. 2-Potassium sulfide (K2S) reacts with heavy metal ions such as lead, cadmium, and mercury to form insoluble water-soluble inorganic sulfides, exhibiting excellent performance in smelting flue gas purification and wastewater deep treatment. Its synergistic effect with nanomaterials (such as graphene-supported CdS) further enhances its photocatalytic performance. Due to its strong alkalinity and complex-breaking ability, potassium sulfide significantly improves the removal rate of metals such as nickel and chromium in high-concentration heavy metal wastewater treatment through the precipitation of water-soluble inorganic sulfides and the synergistic effect with iron salts. Simultaneously, as a precursor for water-soluble inorganic sulfide electrolytes, it achieves high ionic conductivity (10⁻⁶) in solid-state batteries. -3 S / cm). Calcium polysulfide (CaS) x Due to the polysulfide chain structure (S 2- x It combines redox and flocculation functions, and is used not only as a fungicide (lime sulfur mixture) and rubber vulcanizing agent in agriculture, but also to stabilize hexavalent chromium through in-situ chemical reduction in soil remediation, and to reduce the reaction energy barrier and improve cycle stability (capacity after 500 cycles) in potassium-sulfur batteries through catalyst optimization.

[0018] However, there are no reports on the use of ammonium sulfide, potassium sulfide, and calcium polysulfide in improving saline-alkali land and enhancing plant resistance to salt stress. This invention provides the application of water-soluble inorganic sulfides in improving plant resistance to salt stress. Potassium sulfide, ammonium sulfide, and calcium polysulfide can effectively improve the germination ability of plant seeds under salt stress. Calcium polysulfide, in particular, can effectively improve the activity of the plant's antioxidant system and the efficiency of photosynthesis, thereby effectively improving the survival rate and growth performance of plants under salt stress. Simultaneously, the water-soluble inorganic sulfide solution can effectively reduce the EC value (Electrical Conductivity) of saline-alkali soil, thereby effectively improving the germination rate of plant seeds in saline-alkali land and achieving effective improvement of saline-alkali land. Therefore, the application of water-soluble inorganic sulfides provided in this invention in improving plant resistance to salt stress is of great significance for fully utilizing saline-alkali land resources and increasing crop yield. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 The figure shows the effect of water-soluble inorganic sulfides on the germination rate of rapeseed seeds under salt stress in Example 1.

[0021] Figure 2 This is a diagram showing the growth of rapeseed under different treatments 14 days after Example 2.

[0022] Figure 3 The bar graph shows the germination rate of rapeseed at 7 days, the hypocotyl length of rapeseed at 14 days, the root length of rapeseed at 14 days, and the fresh weight of rapeseed at 14 days under different treatments in Example 2.

[0023] Figure 4 This is a diagram showing the germination status of maize on day 7 under different treatments in Example 3.

[0024] Figure 5 The images show the germination rate of maize seeds under different treatments on day 7 and the radicle length of maize seeds under different treatments on day 7 in Example 3.

[0025] Figure 6 This is a diagram showing the germination of sorghum under different treatments on day 7 in Example 3.

[0026] Figure 7 The graph shows the germination rate, coleoptile length, and radicle length of sorghum seeds under different treatments on day 7 in Example 3.

[0027] Figure 8 This is a diagram showing the germination of wheat on day 7 under different treatments in Example 3.

[0028] Figure 9 The figures show the germination rate of wheat seeds under different treatments on day 7, the lower coleoptile of wheat seeds under different treatments on day 7, and the radicle length of wheat seeds under different treatments on day 7, as well as columnar graphs.

[0029] Figure 10 This is a diagram showing the growth and development of maize on day 14 under different treatments in Example 4.

[0030] Figure 11 Example 4 shows bar graphs of germination rate of maize on day 7 under different treatments, plant height of maize on day 14 under different treatments, root length of maize on day 14 under different treatments, and fresh weight of maize on day 14 under different treatments.

[0031] Figure 12 This is a diagram showing the growth and development of wheat on day 14 under different treatments in Example 4.

[0032] Figure 13 The following are bar graphs showing the germination rate of wheat on day 7, plant height of wheat on day 14 under different treatments, root length of wheat on day 14 under different treatments, and fresh weight of wheat on day 14 under different treatments in Example 4.

[0033] Figure 14 This is a diagram showing the growth and development of sorghum under different treatments on day 14 in Example 4.

[0034] Figure 15 The following are bar graphs showing the germination rate of sorghum under different treatments on day 7, the plant height of sorghum under different treatments on day 14, the root length of sorghum under different treatments on day 14, and the fresh weight of sorghum under different treatments on day 14 in Example 4.

[0035] Figure 16 The figure shows the effect of calcium polysulfide on the activities of SOD, POD and CAT in rapeseed leaves under salt stress in Example 5.

[0036] Figure 17 The bar graph shows the effect of calcium polysulfide on the activities of SOD, POD, and CAT in maize roots and stems after 14 days of treatment in Example 5.

[0037] Figure 18 The bar graph shows the effect of calcium polysulfide on the MDA and Pro content in maize roots and stems after 14 days of treatment in Example 5.

[0038] Figure 19 The bar graph shows the effect of calcium polysulfide on the activities of SOD, POD, and CAT in wheat roots and stems after 14 days of treatment in Example 5.

[0039] Figure 20 The bar graph shows the effect of calcium polysulfide on the MDA and Pro content in wheat roots and stems after 14 days of treatment in Example 5.

[0040] Figure 21 Example 6: Effects of calcium polysulfide on saline-alkali soil. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0042] In the following examples, the term "solution" refers to "aqueous solution".

[0043] Example 1: Water-soluble inorganic sulfides can enhance the germination ability of rapeseed seeds under salt stress. (1) Experimental method: Select plump, uniformly sized seeds of the Brassica napus variety G135 (sourced from the National Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences). Disinfect the seeds with a 1% sodium hypochlorite solution, then rinse the surface with sterile water to remove the sodium hypochlorite solution. Let the seeds air dry. Use a 4-compartment petri dish (9 cm in diameter), placing 15 seeds in each compartment. Line the bottom with a layer of filter paper (e.g., [missing information]). Figure 1 As shown), add 4 mL of different types of solutions.

[0044] CK control group: 300 mM NaCl solution; Treatment groups: 300 mM NaCl + 50 mg / L ammonium sulfide (50-NS, A1); 300 mM NaCl + 100 mg / L ammonium sulfide (100-NS, A2); 300 mM NaCl + 1000 mg / L ammonium sulfide (1000-NS, A3); 300 mM NaCl + 50 mg / L potassium sulfide (50-KS, B1); 300 mM NaCl + 100 mg / L potassium sulfide (100-KS, B2); 300 mM NaCl + 1000 mg / L potassium sulfide (1000-KS, B3); 300 mM NaCl + 50 mg / L calcium polysulfide (50-CaS, C1); 300 mM NaCl + 100 mg / L calcium polysulfide (100-CaS, C2); 300 mM NaCl + 1000 mg / L calcium polysulfide (1000-CaS, C3).

[0045] 50-NS, 100-NS, and 1000-NS are obtained by adding ammonium sulfide to a 300 mM NaCl solution to achieve ammonium sulfide concentrations of 50 mg / L, 100 mg / L, and 1000 mg / L, respectively; 50-KS, 100-KS, and 1000-KS are obtained by adding potassium sulfide to a 300 mM NaCl solution to achieve potassium sulfide concentrations of 50 mg / L, 100 mg / L, and 1000 mg / L, respectively; 50-CaS, 100-CaS, and 1000-CaS are obtained by adding calcium polysulfide to a 300 mM NaCl solution to achieve calcium polysulfide concentrations of 50 mg / L, 100 mg / L, and 1000 mg / L, respectively.

[0046] Each treatment group had 3 replicates, and the germination rate of seeds after 7 days of treatment was used as the evaluation index for the treatment effect.

[0047] Evaluation criteria for germination rate: The length of the hypocotyl of the seed must be greater than the diameter of the seed.

[0048] (2) Experimental results Figure 1 The figure shows the effect of water-soluble inorganic sulfides on the germination rate of rapeseed seeds under salt stress in Example 1. CK represents 300 mM NaCl solution; A1, A2, and A3 represent the addition of ammonium sulfide to the 300 mM NaCl solution to achieve concentrations of 50 mg / L, 100 mg / L, and 1000 mg / L, respectively; B1, B2, and B3 represent the addition of potassium sulfide to the 300 mM NaCl solution to achieve concentrations of 50 mg / L, 100 mg / L, and 1000 mg / L, respectively; and C1, C2, and C3 represent the addition of calcium polysulfide to the 300 mM NaCl solution to achieve concentrations of 50 mg / L, 100 mg / L, and 1000 mg / L, respectively.

[0049] Under 300 mM NaCl stress, treatment of rapeseed seeds with water-soluble inorganic sulfides significantly improved seed germination rate. For example, treatment with 300 mM NaCl + 100 mg / L calcium polysulfide resulted in a germination rate of up to 84.8%, which was 214% higher than the control (CK). Treatments with 100 mg / L potassium sulfide and 50 mg / L ammonium sulfide increased the germination rate by 207.4% and 133.3%, respectively. Figure 1 (See Table 1); Ammonium sulfide, potassium sulfide, and calcium polysulfide also significantly promoted the growth of hypocotyls and roots in rapeseed. Compared with the control (CK), the 100 mg / L calcium polysulfide treatment increased the growth of hypocotyls and roots by 123.3% and 137.8%, respectively. Figure 1 (and Table 1).

[0050] Table 1. Effects of water-soluble inorganic sulfides on rapeseed seed germination

[0051] In Table 1, CK represents 300 mM NaCl solution; 50-NS, 100-NS, and 1000-NS represent 300 mM NaCl solution with added ammonium sulfide to achieve concentrations of 50 mg / L, 100 mg / L, and 1000 mg / L, respectively; 50-KS, 100-KS, and 1000-KS represent 300 mM NaCl solution with added potassium sulfide to achieve concentrations of 50 mg / L, 100 mg / L, and 1000 mg / L, respectively; and 50-CaS, 100-CaS, and 1000-CaS represent 300 mM NaCl solution with added calcium polysulfide to achieve concentrations of 50 mg / L, 100 mg / L, and 1000 mg / L, respectively.

[0052] Example 2: Water-soluble inorganic sulfides can improve the growth performance of rapeseed under salt stress. (1) Experimental methods After sterilization, rapeseed seeds (G135) were planted in 7 cm × 7 cm seedling pots containing 100 g vermiculite. The pots were then watered with 150 mL of different solutions: 300 mM NaCl (NaCl), 300 mM NaCl + 50 mg / L (NH₄)₂S (50-NS), 300 mM NaCl + 100 mg / L K₂S (100-KS), and 300 mM NaCl + 100 mg / L calcium polysulfide (100-CaS), ensuring the liquid did not overflow. Subsequently, 150 mL of 300 mM NaCl + different concentrations of water-soluble inorganic sulfides was applied every 3 days for a total of 3-4 applications. Germination rate was recorded 7 days after sowing, and hypocotyl length, root length, and fresh weight were measured 14 days later. The effects of water-soluble inorganic sulfides on rapeseed growth under salt stress were analyzed.

[0053] NaCl, 300 mM NaCl solution; 100- KS, 50- NS, 100- CaS, which are potassium sulfide, ammonium sulfide, and calcium polysulfide added to the 300 mM NaCl solution to make the concentration of potassium sulfide 100 mg / L, the concentration of ammonium sulfide 50 mg / L, and the concentration of calcium polysulfide 100 mg / L, respectively.

[0054] (2) Experimental results Figure 2 This is a diagram showing the growth of rapeseed under different treatments 14 days after Example 2.

[0055] Figure 3 The bar graph shows the germination rate of rapeseed at 7 days, the hypocotyl length of rapeseed at 14 days, the root length of rapeseed at 14 days, and the fresh weight of rapeseed at 14 days under different treatments in Example 2.

[0056] exist Figures 2-3 In the table, NaCl was added to a 300 mM NaCl solution; 100- KS, 50- NS, and 100- CaS were added to the 300 mM NaCl solution, respectively, to achieve a concentration of 100 mg / L for potassium sulfide, 50 mg / L for ammonium sulfide, and 100 mg / L for calcium polysulfide. The bar chart represents the mean ± SD (n = 3), with different letters indicating... p The difference was significant at the <0.05 level.

[0057] Based on the germination rate of rapeseed after 7 days, treatments with ammonium sulfide, potassium sulfide, and calcium polysulfide significantly improved the germination rate and post-emergence growth of rapeseed. Figures 2-3Compared with the control, the germination rates of 100-KS, 50-NS, and 100-CaS increased by 230.5%, 282%, and 290.6%, respectively. Figure 3 From the perspective of 14-day growth performance, 100 mg / L calcium polysulfide can promote the elongation of the hypocotyl in rapeseed, increasing it by 19%, while other treatments have no significant effect. Figure 3 However, it can significantly promote the increase of rapeseed root length and fresh weight, with the effect of 100 mg / L calcium polysulfide being the most obvious, such as promoting a 103.8% increase in root length ( ). Figure 3 The fresh weight increased by 43.2% ( Figure 3 ).

[0058] The above experimental results show that the use of ammonium sulfide, potassium sulfide and calcium polysulfide can improve the growth of rapeseed under salt stress, and increase the crop germination rate and yield.

[0059] Example 3: Under salt stress, calcium polysulfide can enhance the germination ability of other crop seeds. Experimental materials: Maize variety "Zhengdan 958" (commercially available); sorghum variety "Zhongke Tian 438" (provided by the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences); wheat variety "Bainong 607" (provided by the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences).

[0060] (1) Experimental methods The difference between the experimental method and that in Example 1 is: Rapeseed was replaced with corn seeds, sorghum seeds, and wheat seeds, respectively. CK represents a water control; NaCl indicates a 214 mM NaCl solution; for relatively more salt-tolerant gramineous crops (maize, wheat, and sorghum), a 214 mM NaCl solution (with a conductivity of approximately 21.4 mS / cm) is used. -1 For salt-sensitive rapeseed, use a 300 mM NaCl solution (with a conductivity of approximately 30 mS / cm). -1 This concentration gradient significantly inhibits seed germination and seedling growth, but does not lead to complete death, making it suitable for salt tolerance evaluation and mitigation effect studies.

[0061] Treatment groups: 214 mM NaCl + 10 mg / L calcium polysulfide (10-CaS); 214 mM NaCl + 100 mg / L calcium polysulfide (100-CaS); 214 mM NaCl + 1000 mg / L calcium polysulfide (1000-CaS).

[0062] 10-CaS, 100-CaS, and 1000-CaS were obtained by adding calcium polysulfide to a 214 mM NaCl solution to achieve concentrations of 10 mg / L, 100 mg / L, and 1000 mg / L, respectively.

[0063] (2) Experimental results Figure 4 This is a diagram showing the germination status of maize on day 7 under different treatments in Example 3.

[0064] Figure 5 The images show the germination rate of maize seeds under different treatments on day 7 and the radicle length of maize seeds under different treatments on day 7 in Example 3.

[0065] Figure 6 This is a diagram showing the germination of sorghum under different treatments on day 7 in Example 3.

[0066] Figure 7 The graph shows the germination rate, coleoptile length, and radicle length of sorghum seeds under different treatments on day 7 in Example 3.

[0067] Figure 8 This is a diagram showing the germination of wheat on day 7 under different treatments in Example 3.

[0068] Figure 9 The graph shows the germination rate, coleoptile length, and radicle length of wheat seeds under different treatments on day 7 in Example 3.

[0069] exist Figures 4-9 In the table, CK represents the water control; NaCl is a 214 mM NaCl solution; 10-CaS, 100-CaS, and 1000-CaS are obtained by adding calcium polysulfide to a 214 mM NaCl solution to achieve concentrations of 10 mg / L, 100 mg / L, and 1000 mg / L, respectively. The bar chart represents the mean ± SD (n = 3), with different letters indicating the concentrations at different levels. p The difference was significant at the <0.05 level.

[0070] Based on the germination experiment results, 100 mg / L calcium polysulfide can significantly improve the germination rate of maize (…). Figures 4-5 ),wheat( Figures 8-9 ) and sorghum ( Figures 6-7 Seed germination ability under salt stress.

[0071] Compared with 214 mM NaCl solution, 100 mg / L calcium polysulfide increased the germination rate of maize by 61.2%. Figure 5The radicle length was 122.2% ( Figure 5 ); increased the germination rate of wheat by 52.9% ( Figure 9 The radicle length was 116.0%. Figure 9 ); increased the germination rate of sorghum by 79.3% ( Figure 7 The radicle length was 68.86%. Figure 7 ).

[0072] Example 4: Under salt stress, calcium polysulfide can improve the growth performance of other crops. Experimental materials: Maize variety "Zhengdan 958" (commercially available); sorghum variety "Zhongke Tian 438" (provided by the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences); wheat variety "Bainong 607" (provided by the Institute of Genetics and Developmental Biology, Chinese Academy of Sciences).

[0073] (1) Experimental methods The difference from the experimental method in Example 2 is that rapeseed seeds were replaced with corn seeds, sorghum seeds, and wheat seeds, respectively. CK represents the water control; NaCl represents a 214 mM NaCl solution; 10-CaS, 100-CaS, and 1000-CaS represent calcium polysulfide added to a 214 mM NaCl solution to achieve concentrations of 10 mg / L, 100 mg / L, and 1000 mg / L, respectively.

[0074] (2) Experimental results Figure 10 This is a diagram showing the growth and development of maize on day 14 under different treatments in Example 4.

[0075] Figure 11 Example 4 shows bar graphs of germination rate of maize on day 7 under different treatments, plant height of maize on day 14 under different treatments, root length of maize on day 14 under different treatments, and fresh weight of maize on day 14 under different treatments.

[0076] Figure 12 This is a diagram showing the growth and development of wheat on day 14 under different treatments in Example 4.

[0077] Figure 13 The following are bar graphs showing the germination rate of wheat on day 7, plant height of wheat on day 14 under different treatments, root length of wheat on day 14 under different treatments, and fresh weight of wheat on day 14 under different treatments in Example 4.

[0078] Figure 14 This is a diagram showing the growth and development of sorghum under different treatments on day 14 in Example 4.

[0079] Figure 15The following are bar graphs showing the germination rate of sorghum under different treatments on day 7, the plant height of sorghum under different treatments on day 14, the root length of sorghum under different treatments on day 14, and the fresh weight of sorghum under different treatments on day 14 in Example 4.

[0080] exist Figures 10-15 In the study, CK (control) was water; NaCl was a 214 mM NaCl solution; and 10-CaS, 100-CaS, and 1000-CaS were obtained by adding calcium polysulfide to a 214 mM NaCl solution to achieve concentrations of 10 mg / L, 100 mg / L, and 1000 mg / L, respectively. The bar chart represents the mean ± SD (n = 3), with different letters indicating different concentrations. p The difference was significant at the <0.05 level.

[0081] Compared with NaCl (214 mM NaCl solution), 100 mg / L calcium polysulfide increased the germination rate of maize by 56.25%. Figure 11 The plant height was 31.6%. Figure 11 The root length is 62.0% ( Figure 11 The fresh weight was 88.49%. Figure 11 ); increased the germination rate of wheat by 257.18% ( Figure 13 The plant height was 43.3%. Figure 13 The root length is 47.05%. Figure 13 The fresh weight was 16.47%. Figure 13 ); Increased the germination rate of sorghum by 53% ( Figure 15 The plant height was 39.9% ( Figure 15 The root length is 87.6% ( Figure 15 The fresh weight was 69.23%. Figure 15 ).

[0082] The experimental results above show that 100 mg / L calcium polysulfide significantly increased plant height, root length, and fresh weight of maize, wheat, and sorghum under salt stress. The use of calcium polysulfide can promote crop growth under salt stress.

[0083] Example 5: Under salt stress, calcium polysulfide alters the redox balance in plants. (1) Experimental methods After sterilization, rapeseed seeds were planted in 7 cm × 7 cm seedling pots containing 100 g of vermiculite. The pots were then watered with 150 mL of water (CK), 300 mM NaCl (NaCl), and 300 mM NaCl + 100 mg / L calcium polysulfide (100-CaS), ensuring the liquid did not overflow. Subsequently, 50 mL of 300 mM NaCl + different concentrations of calcium polysulfide was applied every 3 days for a total of 3 applications. The aboveground and underground parts were harvested after 14 days. The effects of calcium polysulfide on crop physiological indicators under salt stress were analyzed.

[0084] The seedling experimental setup for maize, wheat, and sorghum was basically the same as that for rapeseed, except that the salt stress concentration was uniformly set at 214 mM NaCl, and the calcium polysulfide treatment concentration gradient was the same (0, 100 mg·L⁻¹). -1 The irrigation and monitoring scheme is the same as that used in the rapeseed experiment.

[0085] (2) Experimental results Figure 16 This is a graph showing the effects of calcium polysulfide on the activities of SOD, POD, and CAT in rapeseed leaves under salt stress, as described in Example 5. Figure 16 In the study, 100-CaS was prepared by adding calcium sulfide to a 300 mM NaCl solution to achieve a calcium polysulfide concentration of 100 mg / L; CK was a water control; and NaCl was a 300 mM NaCl solution. The bar chart represents the mean ± SD (n = 3), with different letters indicating different values. p The difference was significant at the <0.05 level.

[0086] Figure 17 The bar graph shows the effect of calcium polysulfide on the activities of SOD, POD, and CAT in maize roots and stems after 14 days of treatment in Example 5.

[0087] Figure 18 The bar graph shows the effect of calcium polysulfide on the MDA and Pro content in maize roots and stems after 14 days of treatment in Example 5.

[0088] Figure 19 The bar graph shows the effect of calcium polysulfide on the activities of SOD, POD, and CAT in wheat roots and stems after 14 days of treatment in Example 5.

[0089] Figure 20 The bar graph shows the effect of calcium polysulfide on the MDA and Pro content in wheat roots and stems after 14 days of treatment in Example 5.

[0090] exist Figures 17-20In the diagram, CK represents the water control; NaCl represents a 214 mM NaCl solution; and 100-CaS represents the addition of calcium polysulfide to a 214 mM NaCl solution to achieve a calcium polysulfide concentration of 100 mg / L. The bar chart represents the mean ± SD (n = 3), with different letters indicating different values. p The difference was significant at the <0.05 level.

[0091] In a 214 mM NaCl solution, the addition of 100 mg / L calcium polysulfide significantly increased the activities of SOD (superoxide dismutase), CAT (catalase), and POD (peroxidase) in roots and stems. Figures 17-20 MDA (malondialdehyde) is a harmful product of membrane lipid oxidation, reflecting the degree of oxidative damage. Treatment with 100 mg / L calcium polysulfide resulted in a decrease in both MDA and proline (Pro) content in the stems and roots of corn and wheat. Specifically, MDA in corn stems and roots decreased significantly by 34.9% and 51.7%, respectively, while MDA in wheat stems and roots decreased significantly by 29% and 63.6%, respectively. Pro in corn stems and roots decreased significantly by 65% ​​and 54.2%, respectively. Figure 18 , Figure 20 In a 300 mM NaCl solution, the addition of calcium polysulfide to achieve a concentration of 100 mg / L significantly increased the CAT activity in rapeseed from 4686.2 U / g protein to 4929.04 U / g protein; SOD and POD activities increased by 31.4% and 72.5%, respectively. 100 mg / L calcium polysulfide exhibits scavenging activity against excess ROS (reactive oxygen species), enhancing the plant's antioxidant defense system and reducing the negative effects of high salt stress. Figure 16 ).

[0092] Example 6: Calcium polysulfide can effectively reduce the electrical conductivity of saline-alkali land. (1) Experimental methods The effects of calcium polysulfide on soil at a depth of 0–30 cm in saline-alkali land were simulated using a cylindrical container 60 cm high and 12 cm in diameter, filled to a depth of 30 cm with soluble salts containing 0.5 wt% (mass fraction) and an electrical conductivity (EC1:5) of (1610 ± 50) μS / cm. -1 Saline-alkali soil with a pH of 8.52±0.05 (soil-to-water ratio 1:5) was irrigated with 200 mL of water (CK) and 100 mg / L calcium polysulfide (A), respectively. Then, 100 mg / L calcium polysulfide was applied every 7 days. The control group was irrigated with deionized water using the same method. 200 mL of water was applied each time, for a total of two applications. Soil samples were taken every 5 cm after 14 days to measure electrical conductivity (EC).

[0093] Figure 21Example 6: Effect of calcium polysulfide on saline-alkali soil. CK represents the water control, and A represents calcium polysulfide. After 14 days of treatment, the effect of calcium polysulfide on the soil depth (0-30cm) of saline-alkali land was simulated using a cylindrical bucket.

[0094] (2) Experimental results In the 0–5 cm soil layer, the organic coefficient (EC) of the water control was 1611 µS / cm, while the EC of the 0–5 cm soil layer in the cylindrical tank decreased to 365 µS / cm after adding 100 mg / L calcium polysulfide. Therefore, compared with water, 100 mg / L calcium polysulfide significantly reduced the soil EC by 77.34%. Figure 21 ).

[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Use of water-soluble inorganic sulfides for increasing salt stress resistance of plants and / or for amelioration of saline soils, characterized in that, The water-soluble inorganic sulfide is at least one selected from the group consisting of potassium sulfide, ammonium sulfide, and calcium polysulfide.

2. A method of increasing salt stress tolerance in plants, characterized in that, The application comprises: Applying a water-soluble inorganic sulfide to at least one of the following objects: (1) a plant under salt stress; (2) a plant at risk of salt stress; (3) a plant growth environment under salt stress; (4) a plant growth environment at risk of salt stress; The water-soluble inorganic sulfide is at least one selected from the group consisting of potassium sulfide, ammonium sulfide, and calcium polysulfide.

3. The method for improving plant salt stress resistance according to claim 2, characterized in that, The water-soluble inorganic sulfide is calcium polysulfide.

4. The method for increasing salt stress tolerance in plants according to claim 2 or 3, characterized in that, The application mode comprises at least one of soil irrigation, foliar spraying, and seed treatment.

5. The method for increasing salt stress tolerance in plants according to claim 2 or 4, wherein, The application mode is soil irrigation, and the application amount of potassium sulfide is 10-25 kg / acre each time; Preferably, the potassium sulfide is applied to the soil in the form of a potassium sulfide-containing solution, and the concentration of potassium sulfide in the potassium sulfide-containing solution is 50-250 mg / L, preferably 80-120 mg / L.

6. The method for increasing salt stress tolerance in plants according to claim 2 or 5, wherein, The application mode is soil irrigation, and the application amount of ammonium sulfide is 10-20 kg / acre each time; Preferably, the ammonium sulfide is applied to the soil in the form of an ammonium sulfide-containing solution, and the concentration of ammonium sulfide in the ammonium sulfide-containing solution is 10-100 mg / L, preferably 40-60 mg / L.

7. The method for increasing salt stress tolerance in plants according to claim 2 or 6, wherein, The application mode is soil irrigation, and the application amount of calcium polysulfide is 10-25 kg / acre each time; Preferably, the calcium polysulfide is applied to the soil in the form of a calcium polysulfide-containing solution, and the concentration of calcium polysulfide in the calcium polysulfide-containing solution is 50-250 mg / L, preferably 80-120 mg / L.

8. The method for increasing salt stress tolerance in plants according to any one of claims 2 to 7, wherein, The water-soluble inorganic sulfide is applied to the seed when the seed is planted in the growth substrate, and the water-soluble inorganic sulfide is applied every 2-4 days thereafter; Preferably, the water-soluble inorganic sulfide is applied to the seed when the seed is planted in the growth substrate, and the water-soluble inorganic sulfide is applied every 3 days thereafter.

9. The method for increasing salt stress tolerance in plants according to any one of claims 2 or 8, wherein, The plant growth environment under salt stress comprises a saline-alkali soil with a salt content of 0.3wt%-2.0wt%.

10. A composition for improving salt stress resistance of a plant, characterized by, The composition comprises a water-soluble inorganic sulfide, and the water-soluble inorganic sulfide is at least one selected from the group consisting of potassium sulfide, ammonium sulfide, and calcium polysulfide; Preferably, the composition comprises ammonium sulfide, potassium sulfide, and calcium polysulfide; Preferably, the composition comprises a fertilizer, a soil conditioner, or a plant growth regulator.

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