CN114538605A

CN114538605A - Method for enhancing heavy metal removal capability of submerged plants

Info

Publication number: CN114538605A
Application number: CN202210380562.8A
Authority: CN
Inventors: 郑正; 黄素珍; 王之锴; 李果; 张威振; 罗兴章
Original assignee: Fuhuan Qingyun Technology Zhejiang Co ltd; Fudan University
Current assignee: Fuhuan Qingyun Technology Zhejiang Co ltd; Fudan University
Priority date: 2022-04-08
Filing date: 2022-04-08
Publication date: 2022-05-27
Also published as: LU503753B1

Abstract

The invention discloses a method for enhancing heavy metal removal capability of submerged plants, and belongs to the technical field of environmental ecological engineering. The method comprises the following steps: the submerged plants and the simulated plants are mixed and planted in the water body containing heavy metals. The heavy metal is one or more of Cu, Pb and Cd, the submerged plant is tape grass, the simulation plant is simulation tape grass, and the planting ratio of the submerged plant to the simulation plant is 1:1 according to the plant number. In the method, the simulated plants provide more attachment areas for microbial communities, the formation of a biological membrane in the whole environment is promoted, the biological membrane plays an important role in controlling the toxicity, migration transformation, biological effectiveness and the like of heavy metals in the water environment, and the addition of the biological membrane can improve the adsorption of the plants on toxic substances, so that the adsorption of real submerged plants on the heavy metals is improved by means of the simulated plants, and the heavy metal removal capacity of the submerged plants is enhanced.

Description

Method for enhancing heavy metal removal capability of submerged plants

Technical Field

The invention belongs to the technical field of environmental ecological engineering, and particularly relates to a method for enhancing heavy metal removal capability of submerged plants.

Background

With the continuous development of industry, a large amount of heavy metals are discharged into water, soil and other environments, so that serious environmental pollution is caused, and particularly, the heavy metals discharged into the water have toxic and harmful effects on animals and plants in water environment, and can be enriched in a food chain, so that the health of people is threatened finally. Therefore, the treatment of heavy metals, especially the treatment of heavy metals in water bodies, is urgent. The bioremediation method of heavy metals is the most commonly used phytoremediation method, which utilizes plants to remove heavy metal pollutants in water or soil, is commonly used for selectively removing heavy metals with low concentration, and has the advantages of high efficiency, environmental protection, no secondary pollution and the like. The submerged plant serving as a typical representative of water plant restoration not only can maintain the diversity of aquatic species and functions, but also has a remarkable purifying effect on water, and plays a huge ecological function. However, with the gradual increase of heavy metal pollution in water, the treatment effect which can be achieved only by using pure submerged plants is limited, and how to improve the treatment effect of the submerged plants on the heavy metal pollution in the water is still a difficult problem to be solved urgently.

Disclosure of Invention

In order to overcome the above problems in the prior art, the present invention aims to provide a method for enhancing the heavy metal removal capacity of submerged plants.

In order to achieve the purpose, the invention provides the following technical scheme:

according to one technical scheme of the invention, the method for enhancing the heavy metal removal capacity of the submerged plant is characterized in that the submerged plant and the simulation plant are mixed and planted in the water body containing the heavy metal.

Furthermore, after the submerged plants and the simulated plants are mixed and planted in the water body containing heavy metals, humic acid is also added into the water body containing heavy metals.

Further, the heavy metal is one or more of Cu, Pb and Cd.

Further, the submerged plant is tape grass (real tape grass), and the simulated plant is simulated tape grass.

Furthermore, the planting ratio of the submerged plants to the simulated plants is 1:1 according to the number of plants.

Further, when the concentration of the heavy metal is 0-1 mg/L, the planting density of the submerged plants is 20-30 plants/m²(ii) a When the concentration of the heavy metal is more than 1mg/L, the planting density of the submerged plant is 40-50 plants/m²(ii) a When the heavy metal is only one, the concentration of the heavy metal is used as an index to select the planting density, and when the heavy metal is two or three, the concentration of the heavy metal with the highest content is used as an index to select the planting density.

Namely, if the heavy metal in the water body is only one of Cu, Pb and Cd, the planting density of the submerged plant is selected according to the concentration of the heavy metal, and when the concentration is 0-1 mg/L, the planting density of the submerged plant is 20-30 plants/m²(ii) a When the concentration is more than 1mg/L, the planting density of the submerged plants is 40-50 plants/m². When two to three heavy metals are present in the water body, for example, Cu is present² ⁺(1000μg/L)、Pb²⁺(100. mu.g/L) and Cd²⁺(10. mu.g/L) in terms of the highest heavy metal content, Cu²⁺The concentration of (A) is selected from the planting density of submerged plants, Cu²⁺The concentration of (a) is 1000. mu.g/L, and is in the range of 0-1 mg/L, so that the planting density of the selected submerged plants is 20-30 plants/m²。

Furthermore, the addition amount of the humic acid is 0.5-2 mg/L.

Furthermore, the main material of the simulation plant is non-woven fabric or plastic, and the simulation plant is a common commercially available product.

Further, the simulation plant is cut into the same length and leaf size of the real submerged plant before use and is washed and dried by tap water for standby.

Compared with the prior art, the invention has the following beneficial effects:

(1) according to the invention, the real submerged plants and the simulation plants are planted in the water body containing heavy metals together, the simulation plants provide more attachment areas for microbial communities, the formation of a biological membrane in the whole environment is promoted, the biological membrane plays an important role in controlling the toxicity, migration transformation, biological effectiveness and the like of the heavy metals in the water environment, and the increase of the biological membrane can improve the adsorption of the plants on toxic substances, so that the adsorption of the real submerged plants on the heavy metals is improved by means of the simulation plants, and the heavy metal removal capability of the submerged plants is enhanced.

(2) The simulated plant taking the non-woven fabric or the plastic as the main material is breathable, flexible, light and thin, has a larger specific surface area compared with a real submerged plant, provides more attachment sites for a microbial community, promotes the growth of a biological membrane in the environment, enables the microorganisms to secrete more extracellular polymeric substances of the biological membrane, and the extracellular polymeric substances of the biological membrane have an adsorption effect on heavy metals, so that the capability of removing the heavy metals by the real submerged plant is enhanced.

(3) Functional groups such as quinonyl, alcoholic hydroxyl, carboxyl, carbonyl and the like contained in humic acid and C ═ C bond and the like in aromatic hydrocarbon can coordinate with heavy metal ions to generate complexation, so that the forms that the heavy metal is easy to dissolve and exchange by submerged plants are reduced, the available forms are increased, the accumulation of Pb, Cu and Cd by the stems and roots of the submerged plants is increased, and the leaching capacity of the heavy metal is reduced; under the stress of heavy metals, humic acid has a promoting effect on the growth of submerged plants, can improve the synthesis of protein and antioxidase, reduce the degree of membrane lipid peroxidation, enhance the resistance of the submerged plants to heavy metals, and simultaneously can obviously change the diversity of submerged plant biomembrane microorganisms under the stress of the heavy metals, relieve the toxicity of the heavy metals of the plants, increase the tolerance of the submerged plants to the heavy metal ions, thereby improving the capacity of the submerged plants to absorb the heavy metals.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 shows the cultivation and domestication process of real Sophora alopecuroides;

FIG. 2 shows the results of SOD, POD and CAT enzyme activities and MDA concentrations in the leaves of real tape grass of example 3, control 1 and control 2;

FIG. 3 shows the EPS concentration results for the simulated bitter herbs of control group 3, the actual bitter herbs of control group 1, the actual bitter herbs of example 3, the simulated bitter herbs of example 3 and the actual bitter herbs of control group 2.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The description and examples are intended to be illustrative only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

The actual eel grasses used in the following examples and comparative examples were obtained from shanghai yuettian biotechnology limited (china, shanghai). Before the experiment, the tape grass is cleaned by tap water and put into the same incubator for 2 weeks for culture and domestication, the culture temperature is 25 +/-2 ℃, and the illumination is as follows: the dark time is 12h:12h, so that the eel grass can reach a better growth state, and the specific culture and domestication process is shown in figure 1.

The artificial tape grass used in the following examples is purchased from https:// www.taobao.com, the main material of the leaf is non-woven fabric or plastic, the artificial tape grass plant is made by adhering the non-woven fabric or plastic of the leaf material on both sides of the surface of the plastic floating framework, and the artificial tape grass plant is trimmed into the same length and the same size of the leaf as the real tape grass before use and is cleaned and dried by tap water for later use.

The lake waters used in the following examples and comparative examples were obtained from the daily lake (N31 DEG 20 ', E121 DEG 30', Shanghai, China) in the school district of Jiangwan of the Fudan university in Popu region, Shanghai, and the water quality index parameters of the lake waters are shown in Table 1.

TABLE 1

Parameter(s)	Value of
		TN	0.50mg/L
TP	0.055mg/L
		pH	7.95
TOC	11.60mg/L
		COD	4.70mg/L
Pb²⁺	Not detected out
		Cd²⁺	Not detected out
Cu²⁺	Not detected out

Example 1

Selecting a 1m multiplied by 1m glass jar to simulate the water body environment, laying 50mm thick quartz sand at the bottom of the jar to simulate the water body sediment environment, providing attachment places for real tape grass and simulated tape grass, transplanting 20 real tape grass and 20 simulated tape grass into the glass jar, inserting the roots of the real tape grass and the simulated tape grass into the 50mm quartz sand, adding lake water into the glass jar to 50cm high, and adding heavy metal Cu into the lake according to the Chinese surface water class V water standard²⁺(1mg/L), 3 sets of parallels were set. In the experimental process, the growing condition of the tape grass is 25 +/-2 ℃, and the illumination is as follows: the dark time ratio is 12h to 12h, and the illumination intensity is 80 μmol · m^-2·s^-1. And after 15 days, acquiring various indexes to be measured of real bitter herb leaves and roots.

Example 2

Selecting a 1m multiplied by 1m glass jar to simulate the water body environment, laying 50mm thick quartz sand at the bottom of the jar to simulate the water body sediment environment, providing attachment places for real tape grass and simulated tape grass, transplanting 40 real tape grass and 40 simulated tape grass into the glass jar, inserting the roots of the real tape grass and the simulated tape grass into the 50mm quartz sand, adding lake water into the glass jar to 50cm high, and adding heavy metal Cu into the lake according to the Chinese surface water class V water standard²⁺(2mg/L), 3 sets of replicates were set. In the experimental process, the growing condition of the tape grass is 25 +/-2 ℃, and the illumination is as follows: the time length ratio of dark is 12h to 12h, and the illumination intensity is 80 mu mol.m^-2·s^-1. And after 15 days, acquiring various indexes to be measured of real tape grass leaves and roots.

Example 3

Selecting a 1m multiplied by 1m glass jar to simulate the water body environment, laying 50mm thick quartz sand at the bottom of the jar to simulate the water body sediment environment, providing attachment places for real tape grass and simulated tape grass, transplanting 20 real tape grass and 20 simulated tape grass into the glass jar, inserting the roots of the real tape grass and the simulated tape grass into the 50mm quartz sand, adding lake water into the glass jar to 50cm high, and adding heavy metal Cu into the lake according to the Chinese surface water class V water standard²⁺(1mg/L)、Pb²⁺(100. mu.g/L) and Cd² ⁺(10. mu.g/L) of the mixture, 3 sets of which were set in parallel. In the experimental process, the growing condition of the tape grass is 25 +/-2 ℃, and the illumination is as follows: the dark time ratio is 12h to 12h, and the illumination intensity is 80 μmol · m^-2·s^-1. And after 15 days, acquiring various indexes to be measured of real tape grass leaves and roots.

Example 4

Selecting a 1 mx 1m glass jar to simulate water body environment, laying 50mm thick quartz sand at the bottom of the jar to simulate water body sediment environment, providing attachment place for real and simulated eel grass, transplanting 20 plantsPlacing real herba Swertiae Dilutae and 20 simulated herba Swertiae Dilutae in a glass jar, inserting the root of real herba Swertiae Dilutae and simulated herba Swertiae Dilutae into 50mm quartz sand, adding lake water into the glass jar to 50cm high, and adding heavy metal Cu into the lake according to the standard of class V water of Chinese surface water²⁺(1mg/L)、Pb²⁺(100. mu.g/L) and Cd²⁺(10 mu g/L), adding 1mg/L humic acid, and setting 3 groups in parallel. In the experimental process, the growing condition of the tape grass is 25 +/-2 ℃, and the illumination is as follows: the dark time ratio is 12h to 12h, and the illumination intensity is 80 μmol · m^-2·s^-1. And after 15 days, acquiring various indexes to be measured of real bitter herb leaves and roots.

Control group 1

Selecting a 1m multiplied by 1m glass jar to simulate the water body environment, laying 50mm thick quartz sand at the bottom of the jar to simulate the water body sediment environment, providing attachment places for real tape grass and simulated tape grass, transplanting 40 real tape grass into the glass jar, inserting the root of the real tape grass into the 50mm quartz sand, adding lake water into the glass jar to 50cm high, and adding heavy metal Cu into the lake according to the standard of class V water of surface water in China²⁺(1mg/L)、Pb²⁺(100. mu.g/L) and Cd²⁺(10. mu.g/L) of the mixture, 3 sets of which were set in parallel. In the experimental process, the growing condition of the tape grass is 25 +/-2 ℃, and the illumination is as follows: the dark time ratio is 12h to 12h, and the illumination intensity is 80 μmol · m^-2·s^-1. And after 15 days, acquiring various indexes to be measured of real bitter herb leaves and roots.

Control group 2

Selecting a 1m multiplied by 1m glass jar to simulate the water body environment, laying 50mm thick quartz sand at the bottom of the jar to simulate the water body sediment environment, providing attachment places for real tape grass and simulated tape grass, transplanting 40 real tape grass into the glass jar, inserting the roots of the real tape grass into the 50mm quartz sand, and adding lake water into the glass jar to 50cm high. In the experimental process, the growing condition of the tape grass is 25 +/-2 ℃, and the illumination is as follows: the dark time ratio is 12h to 12h, and the illumination intensity is 80 μmol. m^-2·s^-1. And after 15 days, acquiring various indexes to be measured of real bitter herb leaves and roots.

Control group 3

A1 m glass cylinder is selected to simulate waterIn the body environment, quartz sand with the thickness of 50mm is paved at the bottom of a cylinder to simulate the sediment environment of a water body, an attachment place is provided for real tape grass and simulated tape grass, 40 strains of the simulated tape grass are transplanted into a glass cylinder, the root of the simulated tape grass is inserted into the quartz sand with the thickness of 50mm, lake water is added into the glass cylinder to the height of 50cm, and the heavy metal Cu is added into the lake according to the V-class water standard of the surface water of China²⁺(1mg/L)、Pb²⁺(100. mu.g/L) and Cd²⁺(10. mu.g/L) of the mixture, 3 sets of which were set in parallel. In the experimental process, the growing condition of the tape grass is 25 +/-2 ℃, and the illumination is as follows: the dark time ratio is 12h:12h, the illumination intensity is 80 mu mol.m^-2·s^-1. And after 15 days, acquiring various indexes to be measured of the leaves and the roots of the simulated tape grass.

Effect verification

(1) Fresh weight, long leaves and roots

The Fresh Weight (FW) of the real Sweetgrass in examples 1-4 and control groups 1-2 was measured using an analytical balance, the moisture and impurities of the leaves were wiped off before weighing, the leaf length and root length of the Sweetgrass were measured using a ruler, and the results were averaged as shown in Table 2.

(2) Total chlorophyll Chl (a + b) content

Cleaning 0.2g of herba Swertiae Dilutae leaves, wiping to dry, placing into 10mL of 96% ethanol solution, leaching in the dark for 24h, and measuring the absorbance values at 649nm and 665nm respectively by using a spectrophotometer. The total Chl (a + b) content was calculated as follows:

C_a＝12.7A₆₆₃-2.69A₆₄₅ (1)

C_b＝22.9A₆₄₅-4.68A₆₆₃ (2)

C＝C_a+C_b (3)

the results of the total chlorophyll Chl (a + b) content test of the real tape grass in examples 1-4 and control groups 1-2 are shown in Table 2 (the data in Table 2 is the average of 3 groups in parallel in the examples and control groups):

TABLE 2

As can be seen from Table 2, the FW, leaf length, root length and total chlorophyll content of the real bitter herbs of examples 1-4 and control group 1, to which the heavy metal ions were added, were all significantly reduced as compared to the real bitter herbs of blank control group 2 to which no heavy metal ions were added, indicating that the heavy metals significantly inhibited the growth of bitter herbs and affected the photosynthesis of bitter herbs. Each index of the real tape grass in the control group 1 is slightly larger than that of the real tape grass in the embodiment 3, which shows that the simulated tape grass may have an inhibition effect on the growth and photosynthesis of the real tape grass, but the inhibition effect is small, and the improvement effect on the heavy metal removal capability of the real tape grass, which is brought by the promotion of the formation of the biological membrane by the simulated tape grass, cannot be counteracted, so that the simulated tape grass still can enhance the heavy metal removal capability of the real tape grass in the overall view. The indexes of the real tape grass in the embodiment 4 are slightly larger than those of the real tape grass in the embodiment 3, which shows that the addition of humic acid with a certain concentration can help to relieve the inhibition of heavy metal and simulation tape grass on the photosynthesis of the real tape grass.

(3) Detection of heavy metals

Drying and grinding the real leaves and roots of tape grass harvested in examples 1-4 and control group 1, weighing certain mass of leaf and root powder, adding certain proportion of HNO₃And HClO₄And (4) carrying out digestion. The digested sample is filtered through a 0.45-micron water system membrane, and the concentrations of Cu, Pb and Cd are measured by inductively coupled plasma atomic emission spectrometry (ICP-MS) after constant volume. The results are shown in table 3 (the data in table 3 is the average of 3 replicates in the examples and control):

TABLE 3

As can be seen from table 3, in example 3 in which the real eel grass and the simulated eel grass are planted in a mixed manner, the content of each heavy metal in the leaves and the roots of the real eel grass is significantly greater than that in the control group 1 in which the real eel grass is planted alone, which indicates that the ability of the real eel grass to remove the heavy metal can be significantly enhanced by planting the simulated eel grass and the real eel grass in a mixed manner. The content of each heavy metal in the leaves and roots of the real tape grass in example 4 is larger than that in example 3, which shows that the addition of humic acid increases the accumulation of Pb, Cu and Cd in the tape grass leaves and roots.

(4) Determination of protein and related enzyme Activity

Sample pretreatment

1g of tape grass leaf is obtained, washed by deionized water and then frozen and preserved by liquid nitrogen to prevent inactivation. The obtained leaves were mixed with a 0.1mol/LPBS solution in terms of weight (g): volume (mL) 1: 9, grinding at 4 ℃, centrifuging at 3500rpm for 10min, taking supernatant, and storing in a-80 ℃ ultra-low temperature refrigerator for later use.

Determination of the Activity of the relevant enzymes

The activities of total protein (TPr), Superoxide dismutase (SOD), Peroxidase (POD, Peroxidase) and Catalase (CAT, Catalase) are measured by using a related kit, and the specific operation steps are carried out according to the instruction of the corresponding kit.

Determination of the concentration of Malondialdehyde (MDA)

The principle of utilizing the related kit to measure the MDA concentration of the bitter herb leaves is as follows: thiobabituric acid (TBA) is capable of undergoing a condensation reaction with MDA in the peroxidized lipid degradation product, which produces a maximum absorption peak at 523 nm.

The results of SOD, POD, CAT enzyme activities and MDA concentration of the leaves of real bitter herbs of example 3, control group 1 and control group 2 are shown in FIG. 2 (taking the average of three groups), wherein the letters a-f indicate significant difference (p <0.05), as can be seen from FIG. 2, the real bitter herbs of control group 1 and example 3 are poisoned by heavy metals, the antioxidant enzyme (SOD, POD, CAT) activities and MDA concentrations are all higher than that of control group 2, compared with the real bitter herbs of control group 1, the antioxidant enzyme SOD activities of the real bitter herbs of example 3 are significantly higher than that of control group 1(p <0.05), the POD, CAT activities and MDA concentrations are also slightly higher than that of control group 1, because the biomembrane stimulates the defense of the antioxidant system under heavy metal conditions, causing the SOD, POD and CAT activities to increase, and plays a certain role in protecting plant cells, the toxic action of heavy metals on plants is relieved, in example 3, because of the existence of the simulated tape grass, the growth of a biological membrane is promoted, the activities of SOD, POD and CAT are more increased, and the degree of relieving the toxic action of heavy metals on plants is stronger.

(5) Determination of EPS concentration

Extracellular Polymeric Substances (EPS) are mainly polysaccharides, proteins and other substances. The EPS can be classified into bound EPS (B-EPS) and soluble EPS (S-EPS) according to the presence state of EPS. Taking 20mL of sample into a centrifugal tube with the specification of 30mL, setting the temperature to be 4 ℃ in a freezing high-speed centrifuge, centrifuging for 15 minutes at 3000g, and separating supernatant to be used as S-EPS to be tested; adding a proper amount of 0.05% NaCl solution into a substrate, uniformly mixing and shaking, then carrying out ultrasonic treatment for 1 minute in an ultrasonic cleaning instrument, then centrifuging for 20 minutes at 12000g and 4 ℃, and extracting supernatant to be used as B-EPS to be tested. In this experiment, the protein and polysaccharide content in B-EPS and S-EPS, respectively, was determined. Protein content was determined using a total protein kit (BCA method) purchased from Nanjing institute of Biotechnology; the polysaccharide content is determined by a phenol-sulfuric acid method. The measurement of the EPS concentration was carried out by taking the simulated tape grass of the control group 3, the real tape grass of the control group 1, the real tape grass of the example 3, the simulated tape grass of the example 3 and the real tape grass of the control group 2, respectively, according to the above method, and the results are shown in fig. 3 (taking the average of three parallel groups), wherein the letters a-e in the figure represent significant differences (p <0.05), and it can be seen from fig. 3 that the EPS concentration of the real tape grass of the control group 1 is significantly increased (p <0.05) compared to the real tape grass of the control group 2 because the biofilm attached to plants can resist external stimuli by secreting EPS, while heavy metals stimulate microorganisms to secrete more EPS. In addition, EPS has strong viscosity, can adhere to more particles, and can make microorganisms attach to the surface of the blade more firmly to form a firmer biological film. The EPS concentration is that the real bitter herbs in the embodiment 3 are obviously larger than the real bitter herbs in the control group 1, the simulated bitter herbs in the embodiment 3 are obviously larger than the simulated bitter herbs in the control group 3 (p is less than 0.05), which shows that the EPS secretion is closely related to the growth of the biomembrane, the EPS concentration of the real bitter herbs in the embodiment 3 is higher than that of the real bitter herbs in the control group 1, and the simulated bitter herbs in the embodiment 3 promote the growth of the biomembrane in the environment, so that the microorganisms secrete more EPS, namely, the simulated plants provide more attachment areas for the microbial community, promote the formation of the biomembrane in the whole environment, and enhance the capability of the real bitter herbs in removing heavy metals.

The above description is intended to be illustrative of the present invention and should not be taken as limiting the invention, as the invention is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Claims

1. A method for enhancing heavy metal removal capability of submerged plants is characterized in that the submerged plants and simulated plants are mixed and planted in a water body containing heavy metals.

2. The method for enhancing heavy metal removal capability of submerged plants according to claim 1, wherein humic acid is further added to the water body containing heavy metals after the submerged plants and the simulated plants are mixed and planted in the water body containing heavy metals.

3. The method for enhancing heavy metal removal capacity of submerged plants according to any one of claims 1-2, wherein the heavy metal is one or more of Cu, Pb and Cd.

4. The method for enhancing heavy metal removal capability of submerged plants according to any one of claims 1-2, wherein the submerged plant is tape grass and the simulated plant is simulated tape grass.

5. The method for enhancing heavy metal removal capacity of submerged plants according to any one of claims 1-2, wherein the planting ratio of the submerged plants to the simulated plants is 1:1 by number of plants.

6. The method for enhancing heavy metal removal capability of submerged plants according to any one of claims 1-2, wherein the planting density of the submerged plants is 20-30 plants/m when the concentration of the heavy metal is 0-1 mg/L²(ii) a The concentration of the heavy metal is more than 1mWhen the density is g/L, the planting density of the submerged plants is 40-50 plants/m²(ii) a When the heavy metal is only one, the concentration of the heavy metal is used as an index to select the planting density, and when the heavy metal is two or three, the concentration of the heavy metal with the highest content is used as an index to select the planting density.

7. The method for enhancing heavy metal removal capacity of submerged plants according to claim 2, wherein the addition amount of the humic acid is 0.5-2 mg/L.