Method for bioremediation of heavy metal pollution in wetland and application thereof

Abstract

The present application relates to a method for repairing heavy metal pollution in wetland by biological synergy and application thereof, comprising the following steps: inoculating arbuscular mycorrhizal fungi agent and reed into heavy metal pollution wetland to repair soil.The present application creatively utilizes the symbiotic system of reed and arbuscular mycorrhizal fungi to repair heavy metal cadmium pollution in wetland sediment.Inoculating arbuscular mycorrhizal fungi agent significantly improves the biomass of reed under heavy metal stress, improves the heavy metal content in reed, reduces the heavy metal cadmium pollution in wetland sediment, and simultaneously solidifies the heavy metal in wetland sediment, so as to repair heavy metal cadmium pollution in wetland.The method for repairing heavy metal pollution in wetland according to the present application is simple in operation, easy in raw material obtaining, low in cost, free from secondary pollution, and has good ecological benefits, which provides an effective means for heavy metal pollution treatment of aquatic ecological system and promotes the sustainable development of ecological environment.

Description

Technical Field

[0001] This invention belongs to the field of ecological environment restoration technology, specifically relating to a method for using biological synergistic remediation of heavy metal pollution in wetlands and its application. Background Technology

[0002] In recent years, with the rapid development of industry and agriculture, the problem of cadmium pollution in wetland sediments has increasingly attracted human attention and has become one of the focal points of environmental science research. Microorganisms are one of the most active components of wetland ecosystems, playing an irreplaceable role in the material cycle. Many microorganisms have the ability to degrade or transform pollutants, and they are highly adaptable and prone to mutation, allowing them to respond more promptly to environmental changes. Numerous studies have shown that microorganisms have a significant impact on the content of heavy metals in water bodies and sediments. Previous studies on the enrichment and transformation of heavy metals by microorganisms have mostly focused on bacterial remediation of heavy metals, neglecting the role of fungi as major participants in the Earth's chemical cycle and energy conversion, in maintaining and regulating wetland ecosystems, buffering and purifying wetland pollution, and especially in their synergistic role with plants in remediating polluted environments.

[0003] Arbuscular mycorrhizal fungi (AMF) are endophytic mycorrhizal fungi capable of mutualistic symbiosis with most plants. They can form mycorrhizal symbiotic systems with plants, increasing the contact area between plant roots and soil, allowing plants to absorb more water and nutrients, promoting plant growth, enhancing plant resistance, and accumulating heavy metals and reducing heavy metal toxicity through growth dilution, chelation, and hyphal enrichment. For example, Chinese invention patent (application number: 201810006916.6) reports a method for remediating cadmium-contaminated soil using arbuscular mycorrhizal fungi in combination with alfalfa. This method can reduce the total cadmium concentration in cadmium-contaminated soil from 5.757 mg / kg to as low as 0.28 mg / kg. Chinese invention patent (application number: 201911363519.5) reports a method for treating cadmium-contaminated soil using rhizomycetes in combination with staghorn sumac. Symbiotic relationships between *Arbuscular mycorrhizalis* and *Stachys rubra* can enhance the *Stachys rubra*'s resistance to cadmium and promote its nutrient absorption and growth. A Chinese invention patent (application number: 202110351395.X) describes a method for remediating cadmium-contaminated soil by intercropping maize and *Wedelia tricuspidata* and inoculating them with arbuscular mycorrhizal fungi. This method utilizes different varieties of maize intercropped or monocropped with *Wedelia tricuspidata*, with or without inoculation with *Arbuscular mycorrhizalis*. Experimental results show that *Arbuscular mycorrhizalis* can reduce the cadmium content in maize seeds and increase the cadmium content in *Wedelia tricuspidata*.

[0004] Currently, the use of arbuscular mycorrhizal fungi (AOMF) for the remediation of cadmium pollution in terrestrial soils is a relatively mature technology and has shown some effectiveness in soil heavy metal remediation. However, these methods are often not applicable to aquatic environments. There is a particular lack of AOMF remediation technologies for heavy metal pollution in aquatic ecosystems, thus limiting the application of AOMF in aquatic heavy metal pollution. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for the bio-co-remediation of heavy metal pollution in wetlands and its application.

[0006] To achieve this objective, the present invention employs the following technical solution:

[0007] In a first aspect, the present invention provides a method for remediating heavy metal pollution in wetlands using biosynergistic methods, the method comprising the following steps:

[0008] Arbuscular mycorrhizal fungi inoculum and reeds were inoculated into wetlands contaminated with heavy metals for soil remediation.

[0009] This invention addresses the relatively limited methods currently available for remediating heavy metal pollution in aquatic ecosystems by proposing a novel approach: utilizing a symbiotic system of reeds and arbuscular mycorrhizal fungi to remediate cadmium (Cd) pollution in wetland sediments. Inoculation with arbuscular mycorrhizal fungi significantly increases the biomass of reeds under heavy metal stress, enhances the heavy metal content within the reeds, reduces cadmium pollution in wetland sediments, and simultaneously solidifies the heavy metals in the sediments, thus remediating cadmium pollution in wetlands. This method for remediating heavy metal pollution in wetlands is simple to operate, uses readily available raw materials, is low-cost, produces no secondary pollution, and offers significant ecological benefits. It provides an effective means for the remediation of heavy metal pollution in aquatic ecosystems, promoting sustainable ecological development.

[0010] Preferably, the arbuscular mycorrhizal fungi include any one or a combination of at least two of *Gymnospermum var. var.*, *Gymnospermum heterotropoides*, or *Gymnospermum scoparia*.

[0011] Preferably, the Glomus caledonium comprises strain AMG16 of Glomus caledonium, with accession number CGMCC No. 41628.

[0012] Preferably, each gram of the arbuscular mycorrhizal fungal agent contains 80-120 (e.g., 80, 83, 86, 88, 90, 93, 96, 98, 100, 103, 106, 108, 110, 113, 116, 118, 120, etc.) arbuscular mycorrhizal fungal spores. Other specific values ​​within this range are also acceptable and will not be elaborated upon here.

[0013] Preferably, the amount of the arbuscular mycorrhizal fungal agent used is 1%-5% of the wetland sediment mass, such as 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc. Other specific values ​​within this range can be selected, and will not be elaborated here.

[0014] Preferably, the arbuscular mycorrhizal fungal inoculant is obtained by the following method:

[0015] Arbuscular mycorrhizal fungal spores and a host plant are inoculated into a propagation substrate, and the substrate is propagated and cultured. After removing the aboveground parts of the host plant, the culture is dried to obtain the arbuscular mycorrhizal fungal inoculum.

[0016] Preferably, the inoculation amount of the arbuscular mycorrhizal fungal spores is 37-225 arbuscular mycorrhizal fungal spores per kilogram of propagation substrate (e.g., 37, 40, 50, 60, 70, 80, 90, 100, 110, 130, 150, 170, 190, 200, 220, 225, etc.). Other specific values ​​within this range can be selected, and will not be elaborated here.

[0017] Preferably, the host plant includes reeds.

[0018] Preferably, the propagation culture time is 25-65 days, such as 25 days, 30 days, 35 days, 40 days, 45 days, 50 days, 55 days, 60 days, 65 days, etc. Other specific values ​​within this range can be selected, and will not be elaborated here.

[0019] Preferably, the drying temperature is 20-30℃ (e.g., 20℃, 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃, 29℃, 30℃, etc.), and the drying time is 5-10 days (e.g., 5 days, 6 days, 7 days, 8 days, 9 days, 10 days, etc.). Other specific values ​​within the above range can be selected, and will not be elaborated here.

[0020] Preferably, the method for remediating heavy metal pollution in wetlands further includes inoculating the heavy metal-polluted wetlands with Bacillus amyloliquefaciens.

[0021] The method for remediating heavy metal pollution in wetlands includes the following steps: inoculating the heavy metal-polluted wetland with arbuscular mycorrhizal fungi, Bacillus amyloliquefaciens, and reeds to carry out soil remediation.

[0022] This invention also creatively discovers that arbuscular mycorrhizal fungi and Bacillus amyloliquefaciens have a synergistic effect in remediating heavy metal cadmium pollution in wetlands.

[0023] Preferably, the Bacillus amyloliquefaciens includes strain A3 of Bacillus amyloliquefaciens with accession number CGMCC No. 6676.

[0024] Preferably, the viable count of the Bacillus amyloliquefaciens agent is not less than 5 x 10⁻⁶. 8 CFU / mL (e.g., 5 x 10) 8 CFU / mL, 6x10 8 CFU / mL, 7x10 8 CFU / mL, 8x10 8 CFU / mL, 9x10 8 CFU / mL, 5x10 9 CFU / mL, 5x10 10 (CFU / mL, etc.) or 2x10 10 CFU / g (e.g., 2 x 10) 10 CFU / g, 3x10 10 CFU / g, 4x10 10 CFU / g, 6x10 10 CFU / g, 8x10 10 CFU / g, 2x10 11 CFU / g, 2x10 12 CFU / g, 2x10 13 (CFU / g, etc.) Other specific point values ​​within the above range can be selected, which will not be elaborated here.

[0025] Preferably, the amount of Bacillus amyloliquefaciens inoculant used is 1%-3% of the wetland sediment mass, such as 1%, 1.2%, 1.4%, 1.6%, 1.8%, 2%, 2.2%, 2.4%, 2.6%, 2.8%, 3%, etc. Other specific values ​​within this range can be selected, and will not be elaborated here.

[0026] Secondly, the present invention provides the application of the method for remediating heavy metal pollution in wetlands according to the first aspect in wetland remediation.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] This invention addresses the relatively limited methods currently available for remediating heavy metal pollution in aquatic ecosystems by proposing a novel approach: utilizing a symbiotic system of reeds and arbuscular mycorrhizal fungi to remediate cadmium (Cd) pollution in wetland sediments. Inoculation with arbuscular mycorrhizal fungi significantly increases the biomass of reeds under heavy metal stress, enhances the heavy metal content within the reeds, and reduces Cd pollution in wetland sediments. Simultaneously, it solidifies the heavy metals in the wetland sediments, thus remediating Cd pollution in wetlands. This method for remediating heavy metal pollution in wetlands is simple to operate, uses readily available raw materials, is low-cost, produces no secondary pollution, and offers significant ecological benefits. It provides an effective means for the remediation of heavy metal pollution in aquatic ecosystems, promoting sustainable ecological development.

[0029] The AMG16 strain involved in this invention is classified and named Glomus caledonium. It is deposited at the China General Microbiological Culture Collection Center (CGMCC) on November 15, 2024, with accession number CGMCCNo.41628. The address is No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing.

[0030] The A3 strain involved in this invention is classified as Bacillus amyloliquefaciens, deposited at the China General Microbiological Culture Collection Center (CGMCC) on October 15, 2012, with accession number CGMCC No. 6676, located at: Institute of Microbiology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing. Detailed Implementation

[0031] To further illustrate the technical means and effects of the present invention, the following describes the technical solution of the present invention in conjunction with preferred embodiments of the present invention. However, the present invention is not limited to the scope of the embodiments.

[0032] Unless otherwise specified, the reagents and consumables used in the following embodiments were purchased from conventional reagent manufacturers in the art; unless otherwise specified, the experimental methods and techniques used were conventional methods and techniques in the art.

[0033] The AMG16 strain involved in the following examples is classified as Glomus caledonium, deposited on November 15, 2024, with accession number CGMCC No. 41628.

[0034] The A3 strain involved in the following examples is classified as Bacillus amyloliquefaciens, deposited on October 15, 2012, with accession number CGMCC No. 6676.

[0035] Preparation Example 1

[0036] This preparation example provides an arbuscular mycorrhizal fungal inoculant AMG16.

[0037] Sandy loam soil from a cadmium-contaminated wetland was sterilized at 121°C for 30 minutes and used as the propagation substrate. Plastic pots were sterilized using 8% sodium hypochlorite, and 3 kg of propagation substrate, 300 AMG16 spores, and 1 L of ultrapure water were added to each pot. Seven reed seedlings from the sampling point were planted in each plastic pot, with the reeds in each pot exhibiting roughly similar growth. After 45 days of cultivation, host plants infected with arbuscular mycorrhizal fungi and sandy loam substrate containing arbuscular mycorrhizal fungal spores and dermal hyphae were obtained. The above-ground parts of the reeds were removed, and the culture in the pots was poured out, evenly distributed, and dried at 25°C for 8 days to obtain the propagated arbuscular mycorrhizal fungal inoculum. Each gram of the *Gloydium scoparia* AMG16 inoculum contained 100 *Gloydium scoparia* AMG16 spores.

[0038] Preparation Example 2

[0039] This preparation example provides an arbuscular mycorrhizal fungal inoculant AMG16.

[0040] Sandy loam soil from a cadmium-contaminated wetland was sterilized at 121°C for 30 minutes and used as the propagation substrate. Plastic pots were sterilized using 8% sodium hypochlorite, and 3 kg of propagation substrate, 250 AMG16 spores, and 1 L of ultrapure water were added to each pot. Seven reed seedlings from the sampling point were planted in each plastic pot, with the reeds in each pot exhibiting roughly similar growth. After 50 days of cultivation, host plants infected with arbuscular mycorrhizal fungi and sandy loam substrate containing arbuscular mycorrhizal fungal spores and basal hyphae were obtained. The above-ground parts of the reeds were removed, and the culture in the pots was poured out, evenly distributed, and dried in an incubator at 25°C for 10 days to obtain the propagated arbuscular mycorrhizal fungal inoculum. Each gram of the *Gloydium scoparia* AMG16 inoculum contained 120 *Gloydium scoparia* AMG16 spores.

[0041] Preparation Example 3

[0042] This preparation example provides an arbuscular mycorrhizal fungal inoculant AMG16.

[0043] Sandy loam soil from a cadmium-contaminated wetland was sterilized at 121°C for 30 minutes and used as the propagation substrate. Plastic pots were sterilized using 8% sodium hypochlorite, and 3 kg of propagation substrate, 200 AMG16 spores, and 1 L of ultrapure water were added to each pot. Seven reed seedlings from the sampling point were planted in each plastic pot, with the reeds in each pot exhibiting roughly similar growth. After 35 days of cultivation, host plants infected with arbuscular mycorrhizal fungi and sandy loam substrate containing arbuscular mycorrhizal fungal spores and basal hyphae were obtained. The above-ground parts of the reeds were removed, and the culture in the pots was poured out, evenly distributed, and dried at 25°C for 8 days in an incubator to obtain the propagated arbuscular mycorrhizal fungal inoculum. Each gram of the *Gloydium scoparia* AMG16 inoculum contained 80 *Gloydium scoparia* AMG16 spores.

[0044] Preparation Example 4

[0045] This preparation example provides a Bacillus amyloliquefaciens A3 bacterial agent.

[0046] Bacillus amyloliquefaciens A3 culture was retrieved from the preservation tube and revived using LB agar at 37°C for 48 hours. Single colonies were picked from the plate and inoculated into 50 mL of LB agar, incubated at 37°C with shaking for 24 hours. Then, a 5% inoculum was added to 500 mL of LB agar and incubated for another 24 hours until the bacterial concentration reached 40 x 10⁻⁶. 8 CFU / mL or higher. The prepared liquid inoculum was inoculated into fermentation medium (composition: 5g peptone, 0.25g NaCl, 0.3g KCl, 0.25g K₂HPO₄, 0.5g MgSO₄·7H₂O, 0.01g FeSO₄·7H₂O, 1L ultrapure water, pH = 7.2). The fermentation temperature was controlled at 37℃, and the fermentation time was 36h, resulting in a viable cell count of 5 x 10⁻⁶. 8 CFU / mL of Bacillus amyloliquefaciens A3 liquid inoculum.

[0047] Example 1

[0048] This embodiment provides a method for remediating humidity-induced heavy metal pollution, the steps of which are as follows:

[0049] (1) The arbuscular mycorrhizal fungus AMG16 prepared in Example 1 and the Bacillus amyloliquefaciens A3 prepared in Example 4 were inoculated into wetland sediments with a cadmium concentration of 10 mg / kg at a mass ratio of 3%. After inoculation, the sediments were placed in sterile basins, and 1 L of ultrapure water was added to each basin.

[0050] (2) After disinfecting the surface of the reed seedlings with a height of 20-35cm and 5-10 leaves collected in situ, plant them in the sterile pots prepared in (1) above. Plant 8 reed seedlings with similar growth conditions in each sterile pot. Control the light time in the greenhouse to 14h and the dark time to 10h, the room temperature to 25℃, water with ultrapure water once every three days, and the repair time to 90 days.

[0051] Example 2

[0052] This embodiment provides a method for remediating humidity-induced heavy metal pollution, the steps of which are as follows:

[0053] (1) The arbuscular mycorrhizal fungus AMG16 prepared in Example 2 and the Bacillus amyloliquefaciens A3 prepared in Example 4 were inoculated into wetland sediments with a cadmium concentration of 10 mg / kg at a mass ratio of 2%. After inoculation, the sediments were placed in sterile basins and 1 L of ultrapure water was added to each basin.

[0054] (2) After disinfecting the surface of the reed seedlings with a height of 20-35cm and 5-10 leaves collected in situ, plant them in the sterile pots prepared in (1) above. Plant 8 reed seedlings with similar growth conditions in each sterile pot. Control the light time in the greenhouse to 14h and the dark time to 10h, the room temperature to 25℃, water with ultrapure water once every three days, and the repair time to 90 days.

[0055] Example 3

[0056] This embodiment provides a method for remediating humidity-induced heavy metal pollution, the steps of which are as follows:

[0057] (1) The arbuscular mycorrhizal fungi AMG16 inoculum obtained in Preparation Example 3 and the Bacillus amyloliquefaciens A3 inoculum obtained in Preparation Example 4 were inoculated into wetland sediments with a heavy metal cadmium concentration of 10 mg / kg at a mass ratio of 4%. After inoculation, the sediments were placed in sterile basins, and 1 L of ultrapure water was added to each basin.

[0058] (2) After disinfecting the surface of the reed seedlings with a height of 20-35cm and 5-10 leaves collected in situ, plant them in the sterile pots prepared in (1) above. Plant 8 reed seedlings with similar growth conditions in each sterile pot. Control the light time in the greenhouse to 14h and the dark time to 10h, the room temperature to 25℃, water with ultrapure water once every three days, and the repair time to 90 days.

[0059] Example 4

[0060] This embodiment provides a method for remediating humidity-induced heavy metal pollution. The only difference between this method and Example 1 is that the number of viable bacteria, such as the arbuscular mycorrhizal fungus AMG16 inoculant obtained in Example 1, is replaced with *Gyrodactylus* (purchased from Gray Algae Biotechnology, catalog number HZB413471, NBCI classification number: 1921602). All other conditions remain unchanged.

[0061] Example 5

[0062] This embodiment provides a method for remediating humidity-induced heavy metal pollution. The only difference between this method and Example 1 is that the number of viable bacteria, such as Bacillus amyloliquefaciens A3 inoculant obtained in Preparation Example 4, is replaced with Bacillus amyloliquefaciens ATCC23350. All other conditions remain unchanged.

[0063] Example 6

[0064] This embodiment provides a method for remediating humidity-induced heavy metal pollution, the steps of which are as follows:

[0065] (1) The arbuscular mycorrhizal fungus AMG16 prepared in Example 1 was inoculated into wetland sediment with a heavy metal cadmium concentration of 10 mg / kg at a mass ratio of 3%. After inoculation, the sediment was placed in sterile basins, and 1 L of ultrapure water was added to each basin.

[0066] (2) After disinfecting the surface of the reed seedlings with a height of 20-35cm and 5-10 leaves collected in situ, plant them in the sterile pots prepared in (1) above. Plant 8 reed seedlings with similar growth conditions in each sterile pot. Control the light time in the greenhouse to 14h and the dark time to 10h, the room temperature to 25℃, water with ultrapure water once every three days, and the repair time to 90 days.

[0067] Example 7

[0068] This embodiment provides a method for remediating heavy metal pollution in wetlands. The only difference between this embodiment and Embodiment 6 is that the concentration of cadmium in wetland sediments in step (1) is 20 mg / kg, while all other conditions remain unchanged.

[0069] Comparative Example 1

[0070] This comparative example provides a method for remediating humidity-induced heavy metal pollution, the steps of which are as follows:

[0071] (1) The Bacillus amyloliquefaciens A3 agent obtained in Preparation Example 4 was inoculated into wetland sediment with a heavy metal cadmium concentration of 10 mg / kg at a mass ratio of 3%. After inoculation, the sediment was placed in sterile basins, and 1 L of ultrapure water was added to each basin.

[0072] (2) After disinfecting the surface of the reed seedlings with a height of 20-35cm and 5-10 leaves collected in situ, plant them in the sterile pots prepared in (1) above. Plant 8 reed seedlings with similar growth conditions in each sterile pot. Control the light time in the greenhouse to 14h and the dark time to 10h, the room temperature to 25℃, water with ultrapure water once every three days, and the repair time to 90 days.

[0073] Comparative Example 2

[0074] This comparative example provides a method for remediating heavy metal pollution in wet conditions. The only difference between this method and Example 1 is that no inoculation with a bacterial agent is used. Reed seedlings with a height of 20-35 cm and 5-10 leaves, collected in situ, are disinfected and then planted in wetland sediment with a cadmium concentration of 10 mg / kg. Eight reed seedlings with similar growth conditions are planted in each sterile pot. The light time in the greenhouse is controlled to be 14 hours and the dark time to be 10 hours. The room temperature is 25°C. The seedlings are watered with ultrapure water every three days. The remediation time is 90 days.

[0075] Comparative Example 3

[0076] This comparative example provides a method for remediating heavy metal pollution in wetlands. The only difference between this method and Comparative Example 2 is that the concentration of cadmium in the wetland sediments is 20 mg / kg, while all other conditions remain unchanged.

[0077] Test case

[0078] This test case tests the repair results of Examples 1-7 and Comparative Examples 1-3.

[0079] Control group 1: The only difference from control group 2 was that the concentration of cadmium in the wetland sediments was 0 mg / kg, while all other conditions remained unchanged.

[0080] Control group 2: The only difference from Example 6 was that the concentration of cadmium in the wetland sediments was 0 mg / kg, while all other conditions remained unchanged.

[0081] The mycorrhizal infection rate of wheat roots was determined using the ink-vinegar staining method.

[0082] The nitrogen, phosphorus, and potassium contents in reed roots and leaves were determined by oxidation digestion according to the "Soil Agricultural Chemical Analysis Methods". Nitrogen and phosphorus were oxidized to ammonium salts and phosphates, respectively. Nitrogen content was determined by alkaline hydrolysis diffusion method, and phosphorus content was determined by molybdenum antimony colorimetric method.

[0083] The Cd content in sediments was determined by microwave digestion. 0.25 g of soil sample was weighed into a digestion vessel, moistened with 1 mL of deionized water, and then 6 mL of HNO3, 3 mL of HCl, and 2 mL of HF were added sequentially. The digestion program was set according to Table 1. After digestion, the acid was removed at 140℃ until the liquid became viscous. The solution was then transferred to a 25 mL volumetric flask and diluted to volume. The Cd content in the test solution was determined by flame osmosis. The results are shown in Table 2.

[0084] Table 1

[0085] step Digestion temperature Duration Pressure limit 1 120℃ 3min 20 bar 2 160℃ 3 min 35 bar 3 190℃ 25 min 40 bar

[0086] Table 2

[0087]

[0088]

[0089] Table 2 shows that the arbuscular mycorrhizal fungus AMG16 inoculant has an infection effect on reeds, with an infection rate of 57.2% under cadmium-free conditions. Although heavy metals in the soil reduce the infection rate of arbuscular mycorrhizal fungi on reeds, the infection rate of the inoculant on reeds can still reach 50.7% and 54.1% after applying cadmium stress of 10 mg / kg and 20 mg / kg, respectively. The symbiotic system of reeds and arbuscular mycorrhizal fungi can significantly improve the removal of cadmium from wetland sediments. After inoculation with AMG16 inoculant, compared with the uninoculated soil, the cadmium removal rate in the soil under cadmium stress of 10 mg / kg and 20 mg / kg increased by 68% and 13.5%, respectively.

[0090] Table 2

[0091]

[0092] As shown in Table 2, the method for biosynergistic remediation of heavy metal pollution in wetlands provided in this application can effectively increase the heavy metal content in reeds and reduce cadmium pollution in wetland sediments.

[0093] Comparing Example 1 and Example 4, it can be seen that the present invention uses a specific arbuscular mycorrhizal fungal agent AMG16, which can effectively remediate humidity-induced heavy metal pollution compared to other arbuscular mycorrhizal fungal agents.

[0094] Comparing Example 1 and Example 5, it can be seen that the present invention uses a specific Bacillus amyloliquefaciens A3, which can effectively remediate humidity-induced heavy metal pollution compared to other Bacillus amyloliquefaciens.

[0095] Comparing Example 1 with Example 6 and Comparative Example 1, it can be seen that arbuscular mycorrhizal fungi AMG16 and Bacillus amyloliquefaciens A3 achieved a synergistic effect in reducing the total cadmium removal rate in wetland sediments.

[0096] The applicant declares that the technical solution of this invention is illustrated by the above embodiments, but this invention is not limited to the above embodiments, that is, it does not mean that this invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the products of this invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of this invention.

[0097] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0098] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for bio-co-remediation of cadmium pollution in wetlands, characterized in that, The method for remediating cadmium pollution in wetlands includes the following steps: Arbuscular mycorrhizal fungi inoculant, Bacillus amyloliquefaciens inoculant, and reed seedlings were inoculated into wetlands contaminated with heavy metal cadmium for soil remediation. The arbuscular mycorrhizal fungus is *Gloydiomycium scoparia*. The Scots Glomerulae species mentioned is the Scots Glomerulae species with accession number CGMCC No. 41628. Glomus caledonium AMG16 strain; each gram of the arbuscular mycorrhizal fungal agent contains 80-100 arbuscular mycorrhizal fungal spores; the amount of the arbuscular mycorrhizal fungal agent used is 3%-4% of the wetland sediment mass; The Bacillus amyloliquefaciens mentioned is Bacillus amyloliquefaciens with accession number CGMCC No. 6676. Bacillus amyloliquefaciens A3 strain; the viable count of the Bacillus amyloliquefaciens agent is not less than 5 × 10⁻⁶. 8 CFU / mL or 2×10 10 CFU / g; the amount of the Bacillus amyloliquefaciens inoculant used is 1%-3% of the wetland sediment mass.

2. The method for bio-co-remediation of cadmium-polluted wetlands according to claim 1, characterized in that, The arbuscular mycorrhizal fungal inoculum was obtained by the following method: Arbuscular mycorrhizal fungal spores and host plants are inoculated into a propagation substrate, and the substrate is propagated. After removing the aboveground parts of the host plant, the culture is dried to obtain the arbuscular mycorrhizal fungal inoculant.

3. The application of the method for bio-co-remediation of heavy metal cadmium pollution in wetlands according to claim 1 or 2 in wetland remediation.

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