Use of nanoscale molybdenum disulfide in promoting plant growth and reducing plant heavy metal accumulation

Abstract

The application provides application of nano molybdenum disulfide in promoting plant growth and reducing plant heavy metal accumulation, belongs to the field of agriculture and environment technology, and plants are planted after the nano molybdenum disulfide is applied to soil, and AM fungi are applied to the soil after the plants are planted; the application concentration of the nano molybdenum disulfide is 20-200 mg / kg; the nano molybdenum disulfide has excellent repair effect on heavy metal contaminated water and soil heavy metal due to its large specific surface area, strong catalysis, adsorption, complexation and other abilities, and can be used as a safe and effective effective exogenous enhancer for promoting plant growth and relieving plant heavy metal toxicity; the AM fungi relieve the adverse effect of cadmium (Cd) on plant growth through a plant stabilization process; the combined application of the nano molybdenum disulfide and the AM fungi in heavy metal contaminated soil has important value for improving the safety of vegetable production.

Description

Technical Field

[0001] This invention belongs to the field of agricultural and environmental technology, and in particular relates to the application of nano-molybdenum disulfide in promoting plant growth and reducing the accumulation of heavy metals in plants. Background Technology

[0002] High cadmium concentrations in soil can negatively impact crop yield and quality. When crops absorb heavy metals exceeding the maximum permissible concentration, they can enter the food chain and negatively affect animal and human health, potentially causing serious public health incidents. Furthermore, because heavy metals in soil are relatively stable and difficult to migrate out, they significantly negatively impact the physical, chemical, and biological properties of soil, further affecting the stability of soil structure and function. Controlling Cd pollution in soil has attracted widespread attention and become a hot topic in ongoing research. However, given the current situation, halting large-scale farming in lightly to moderately polluted farmland and undertaking long-term phytoremediation or other costly physicochemical engineering remediation is highly impractical. Therefore, for lightly to moderately polluted farmland soils, utilizing fast-growing, high-biomass, and heavy metal-tolerant crops / plants through exogenous enhancement and technological modification to reduce cadmium accumulation has become an important research direction in the field of phytoremediation.

[0003] However, the effects of phytoremediation alone are unstable. The combined remediation of nanomaterials, microorganisms and plants has great application potential for improving soil quality, reducing the accumulation of heavy metals in plants, and ensuring the environmental safety of crops. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide the application of nano-molybdenum disulfide in promoting plant growth and reducing the accumulation of heavy metals in plants.

[0005] This invention provides the application of nano-molybdenum disulfide in promoting plant growth or reducing the accumulation of heavy metals in plants, wherein the nano-molybdenum disulfide is applied to the soil and then plants are planted.

[0006] Preferably, the application concentration of the nano-molybdenum disulfide is 20–200 mg / kg.

[0007] Preferably, AM fungi are applied to the soil after the plants are planted.

[0008] Preferably, the amount of AM fungus applied is 5-15 mL / kg soil, and the spore concentration of AM fungus is greater than 100 spores / mL.

[0009] Preferably, the plant includes coriander.

[0010] Preferably, promoting plant growth includes increasing the dry weight of the aboveground parts of the plant.

[0011] Preferably, reducing the accumulation of heavy metals in plants includes reducing the heavy metal content in the aboveground parts of plants.

[0012] Preferably, the heavy metal includes cadmium.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides the application of nano-molybdenum disulfide in promoting plant growth or reducing the accumulation of heavy metals in plants. Applying nano-molybdenum disulfide to the soil can significantly promote plant growth and increase the dry weight of the aboveground parts of plants; at the same time, it can reduce the accumulation of heavy metals in the aboveground parts of plants and reduce the heavy metal content in the soil.

[0014] Nano-molybdenum disulfide, due to its large specific surface area and strong catalytic, adsorption, and complexation capabilities, exhibits excellent remediation effects on heavy metal-contaminated water and soil. It can serve as a safe and effective exogenous enhancer that promotes plant growth and alleviates cadmium toxicity in plants. The AM fungi mentioned above mitigate the adverse effects of cadmium (Cd) on plant growth through a plant stabilization process. The AM fungi can enhance plants' resistance to heavy metal toxicity and prevent plant absorption of heavy metals by providing a heavy metal barrier or excreting organic compounds (such as glomalin) to chelate heavy metal ions. The combined application of nano-molybdenum disulfide and AM fungi in heavy metal-contaminated soils is of significant value in improving the safety of vegetable production. Attached Figure Description

[0015] Figure 1 The present invention relates to the aboveground dry weight and root dry weight of coriander grown under two Cd pollution levels, where a represents the effect of different concentrations of nano-molybdenum disulfide and AM fungi on the aboveground biomass of coriander under cadmium stress; b represents the effect of different concentrations of nano-molybdenum disulfide and AM fungi on the underground biomass of coriander under cadmium stress.

[0016] Figure 2 The effects of different concentrations of MoS2NMs, Cd pollution, and AM fungi on Cd concentration in the aboveground parts;

[0017] Figure 3 Cd extracted from soils under different concentrations of MoS2NMs, Cd pollution, and AM fungi;

[0018] Figures 1-3In the table: 0, b1, b2, and b3 represent the four levels of MoS2NMs addition (0, 50, 100, and 300 mg / kg), respectively; Cd0-M, Cd0+M, Cd3-M, and Cd3+M represent no AM fungus inoculation, AM fungus inoculation at 0 mg / kg, AM fungus inoculation at 3 mg / kg Cd, and AM fungus inoculation at 3 mg / kg Cd, respectively; the vertical bars represent the standard error of the mean; significant differences between treatments are indicated by different lowercase letters and are analyzed using Duncan's multiple range test following a significant one-way ANOVA (p < 0.05). Detailed Implementation

[0019] This invention provides the application of nano-molybdenum disulfide in promoting plant growth or reducing the accumulation of heavy metals in plants, wherein the nano-molybdenum disulfide is applied to the soil and then plants are planted.

[0020] In this invention, the preferred application concentration of the nano-molybdenum disulfide is 20–200 mg / kg, more preferably 50–100 mg / kg; the nano-molybdenum disulfide (MoS2NMs) is preferably purchased from Pantian Powder Materials Co., Ltd. (Shanghai, China); the preferred particle size of the nano-molybdenum disulfide is 120 nm, and the purity is 99%. In this invention, the preferred application method of the nano-molybdenum disulfide is direct and uniform mixing with the soil. In this invention, the preferred planting plant is coriander; the coriander is preferably transplanted into the soil after seedling cultivation. Preferably, the present invention applies AM fungi to the soil after the coriander is transplanted; further, the AM fungi are applied 1-3 days after the coriander is transplanted; the present invention does not have any particular limitation on the specific species and source of the AM fungi, and any known AM fungi can be used; in the specific implementation of the present invention, the AM fungi is Rhizophagus irregularis DAOM 197198; the application amount of the AM fungi is 5-15 mL / kg soil, more preferably 8-12 mL / kg soil, and even more preferably 10 mL / kg soil; the spore concentration of the AM fungi is greater than 100 spores / mL.

[0021] In this invention, the AM fungi are preferably grown on a culture medium containing carrot roots. This invention does not specifically limit the type of culture medium; any conventional AM fungal culture medium in the art, such as MSR medium, can be used. The purpose of adding carrot roots is to establish a symbiotic relationship between the AM fungi and carrot roots, thereby improving the cultivation of the AM fungi. In this invention, the culture medium containing the AM fungi is preferably dissolved using a citrate-sodium citrate buffer solution. Then, some carrot roots are chopped, filtered, and the spores and roots are collected. The filtration is preferably performed using a 38μm nylon mesh. The collected spores and roots are rinsed thoroughly with deionized water. Finally, the spores and roots are resuspended in deionized water to obtain a bacterial suspension containing AM fungal spores and hyphae.

[0022] In this invention, the promotion of plant growth preferably includes increasing the dry weight of the aboveground parts of the plant; the reduction of heavy metal accumulation in plants preferably includes reducing the heavy metal content of the aboveground parts of the plant; the heavy metal preferably includes cadmium.

[0023] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0024] Nano-molybdenum disulfide (MoS2NMs) was purchased from Pantian Powder Materials Co., Ltd. (Shanghai, China); the particle size was 120 nm and the purity was 99%.

[0025] AM fungus Rhizophagus irregularis DAOM197198 was provided by the Department of Plant Nutrition, China Agricultural University.

[0026] Example 1

[0027] (1) Test soil

[0028] Topsoil (depth 0–20 cm) from typical agricultural land in Zhuzhou City, Hunan Province (27°5002.900N, 113°2509.500E). The soil in the study area has been contaminated with heavy metals from wastewater discharged from a nearby smelter since the early 1980s, with a cadmium concentration of 0.3 mg / kg. Air-dried soil and low-phosphorus soil were mixed at a mass ratio of 3:1 and used as the culture medium for pot experiments. The low-phosphorus soil was obtained from farmland in Quzhou County, Handan City, Hebei Province, with an available phosphorus content of 7.85 mg / kg.

[0029] (2) Addition of heavy metal cadmium

[0030] Prepare a 0.456 g / L 3CdSO4·8H2O solution, add 12 mL of the solution to 8 kg of soil, and sieve and mix thoroughly.

[0031] (3) Addition of nano-molybdenum disulfide

[0032] Weigh out 0.4g (50mg / kg) of nano molybdenum disulfide per portion, for a total of 2 portions, and add them to 2 separate bags (one containing 8kg of soil with heavy metals and one containing 8kg of soil without heavy metals) and mix well.

[0033] (4) Disinfection and inoculation of coriander seeds

[0034] First, sterilize the potting soil and fill it into seed trays. Sterilize the seeds with 10% H2O2 for 30 minutes, wash them with deionized water, and then germinate them. Sow 15 germinated seeds in each cell and cultivate them in a greenhouse for 2 weeks.

[0035] (5) Transplanting and cultivation of coriander

[0036] Two weeks after seedling cultivation, select 9-12 seedlings of similar growth from each seedling tray and transplant them into flowerpots, ensuring that all 32 pots have the same growth rate. During transplanting, add 50mL of indigenous bacteria filtrate and then water thoroughly. Indigenous bacteria filtrate preparation method: Mix 2kg of soil with deionized water at a 1:2 ratio, then filter through a 38μm membrane to obtain 4000mL of filtrate.

[0037] (6) Addition of AM fungi

[0038] Rhizophagus irregularis DAOM197198, mycelia and spores grew on a medium containing carrot roots. Before the experiment, the medium (a pure culture system of R. irregularis) was first dissolved in citrate-sodium citrate buffer. Next, some carrot roots were chopped, and spores and roots were sieved through a 38 μm nylon mesh. The citrate-sodium citrate buffer was then rinsed off the spores and roots with deionized water. Finally, the spores and roots were rinsed into sterile glass bottles, and deionized water was added to obtain a bacterial suspension containing 100 R. irregularis spores / mL and mycelia.

[0039] Two days after transplanting, inoculate the soil with bacteria by pouring 10 mL of bacterial solution into the soil to be inoculated, or pour 10 mL of deionized water into the soil to be uninoculated.

[0040] (7) Post-processing management and sample collection

[0041] During the coriander growing season, meticulous management is essential to minimize the impact of irrelevant environmental factors. Regularly adjust the position and ventilation of each pot, water regularly to maintain soil moisture content at 70-80% of maximum field capacity (42%), and take precautions against pests and diseases. Harvest samples 6 weeks after transplanting.

[0042] Example 2

[0043] (1) Test soil

[0044] Topsoil (depth 0–20 cm) from typical agricultural land in Zhuzhou City, Hunan Province (27°5002.900N, 113°2509.500E). The soil in the study area has been contaminated with heavy metals from wastewater discharged from a nearby smelter since the early 1980s, with a cadmium concentration of 0.3 mg / kg. Air-dried soil was mixed with low-phosphorus soil in a 3:1 ratio and used as the culture medium for pot experiments; the low-phosphorus soil was obtained from farmland in Quzhou County, Handan City, Hebei Province, with an available phosphorus content of 7.85 mg / kg.

[0045] (2) Addition of heavy metal cadmium

[0046] Prepare a 0.456 g / L 3CdSO4·8H2O solution, add 12 mL of the solution to each 8 kg soil sample, and sieve and mix thoroughly.

[0047] (3) Addition of nano-molybdenum disulfide

[0048] Weigh out 0.8g (100mg / kg) of nano molybdenum disulfide per portion, for a total of 2 portions, and add them to 2 separate bags (one containing 8kg of soil with heavy metals and one containing 8kg of soil without heavy metals) and mix well.

[0049] (4) Disinfection and inoculation of coriander seeds

[0050] First, sterilize the potting soil and fill it into the seedling trays. Simultaneously, sterilize the seeds with 10% H₂O₂ for 30 minutes, wash them with deionized water, and germinate them. After thoroughly watering the soil in the seedling trays with deionized water, scatter the treated seeds into the trays, sowing 10 seeds per hole, and then cover with a thin layer of soil. Cultivate in a greenhouse for 2 weeks.

[0051] (5) Transplanting and cultivation of coriander

[0052] Two weeks after seedling cultivation, select 9-12 seedlings of similar growth from each seedling tray and transplant them into flowerpots, ensuring that all 32 pots have the same growth rate. During transplanting: first add 50mL of water, then transplant, then add 50mL of indigenous bacteria filtrate, and finally water thoroughly.

[0053] (6) Addition of AMF

[0054] Rhizophagus irregularis DAOM197198, mycelia and spores grew on a medium containing carrot roots. Before the experiment, the medium (a pure culture system of R. irregularis) was first dissolved in citrate-sodium citrate buffer. Next, some carrot roots were chopped, and spores and roots were sieved through a 38 μm nylon mesh. The citrate-sodium citrate buffer was then rinsed off the spores and roots with deionized water. Finally, the spores and roots were rinsed into sterile glass bottles, and a certain amount of deionized water was added to obtain a bacterial suspension containing R. irregularis spores and mycelia.

[0055] Two days after transplanting, inoculate the soil with bacteria by pouring 10 mL of bacterial solution into the soil to be inoculated, or pour 10 mL of deionized water into the soil to be uninoculated.

[0056] (7) Post-processing management and sample collection

[0057] During the coriander growing season, meticulous management is essential to minimize the impact of irrelevant environmental factors. Regularly adjust the position and ventilation of each pot, and water regularly to maintain soil moisture content at 70-80% of maximum field capacity (42%). Pay close attention to disease and pest control, and spray insecticides promptly. Harvest samples 6 weeks after transplanting.

[0058] Example 3

[0059] (1) Test soil

[0060] Topsoil (depth 0–20 cm) from typical agricultural land in Zhuzhou City, Hunan Province (27°5002.900N, 113°2509.500E). The soil in the study area has been contaminated with heavy metals from wastewater discharged from a nearby smelter since the early 1980s, with a cadmium concentration of 0.3 mg / kg. Air-dried soil was mixed with low-phosphorus soil in a 3:1 ratio and used as the culture medium for pot experiments; the low-phosphorus soil was obtained from farmland in Quzhou County, Handan City, Hebei Province, with an available phosphorus content of 7.85 mg / kg.

[0061] (2) Addition of heavy metal cadmium

[0062] Prepare a 0.456 g / L 3CdSO4·8H2O solution, add 12 mL of the solution to each 8 kg soil sample, and sieve and mix thoroughly.

[0063] (3) Addition of nano-molybdenum disulfide

[0064] Weigh out 2.4g (300mg / kg) of nano molybdenum disulfide per portion, for a total of 2 portions, and add them to 2 separate bags (one containing 8kg of soil with heavy metals and the other containing 8kg of soil without heavy metals) and mix well.

[0065] (4) Disinfection and inoculation of coriander seeds

[0066] First, sterilize the potting soil and fill it into the seedling trays. Simultaneously, disinfect and germinate the seeds. Scatter the treated seeds in the trays, sowing 10-20 seeds per hole, then cover with a thin layer of soil. Cultivate in a greenhouse for approximately two weeks.

[0067] (5) Transplanting and cultivation of coriander

[0068] Two weeks after seedling cultivation, select 9-12 seedlings of similar growth from the seedling trays and transplant them into each flowerpot. During transplanting: first add 50mL of water, then transplant, then add 50mL of indigenous bacteria filtrate, and then water thoroughly.

[0069] (6) Addition of AMF

[0070] Two days after transplanting, inoculate the soil with bacteria by pouring 10ml of bacterial solution into the soil to be inoculated, or pour 10ml of deionized water into the soil to be uninoculated.

[0071] (7) Post-processing management and sample collection

[0072] During the coriander growing season, meticulous management is essential to minimize the impact of irrelevant environmental factors. Regularly adjust the position and ventilation of each pot, and water regularly to maintain soil moisture content at 70-80% of maximum field capacity (42%). Pay close attention to disease and pest control, and spray insecticides promptly. Harvest samples 6 weeks after transplanting.

[0073] The plant materials in Examples 1-3 were collected after 6 weeks of cultivation, and the aboveground and underground biomass, cadmium content and other indicators were measured respectively.

[0074] At harvest, thoroughly rinse the coriander plants with tap water for 2 minutes, then rinse three times with deionized water. First, blanch the plants in an oven at 105℃ for 30 minutes, then set the oven temperature to 70℃ and dry to constant weight. After cooling to room temperature, quickly open the oven and remove the samples. Immediately weigh and record the dry weight using an analytical balance. Analyze the cadmium content of the plants using ICP-OES.

[0075] The results are as follows Figures 1-3 As shown, the combined application of low concentrations of MoS2NMs (50, 100 mg / kg) and AM fungi has a synergistic effect on reducing cadmium uptake in the aboveground parts of coriander.

[0076] The combined application of MoS2NMs and AM fungi can promote the growth of coriander, a major crop, and reduce cadmium accumulation, providing theoretical support for further research and utilization of combined remediation in the field of cadmium-polluted environmental remediation.

[0077] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. The application of nano-molybdenum disulfide in promoting the aboveground growth of coriander under cadmium stress, characterized in that, After applying the nano-molybdenum disulfide to the soil, coriander is planted; the application concentration of the nano-molybdenum disulfide is 50~300mg / kg.

2. The application of nano-molybdenum disulfide in reducing cadmium accumulation in the aboveground parts of coriander, characterized in that, After applying the nano-molybdenum disulfide to the soil, coriander is planted; the application concentration of the nano-molybdenum disulfide is 50~300mg / kg.

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