A Screening Method and Application of Ecological Restoration Plants for Open-pit Mining Abandoned Lands

Abstract

The present invention relates to a screening method and application of ecological restoration plants for opencast mining waste land, belonging to the technical field of mine ecological restoration. The screening method of the present invention comprises the following steps: conducting preliminary screening by measuring plant biomass and the content of organic acids secreted by roots; calculating the total mean value of membership functions for secondary screening; and combining the species that overlap in the ecological restoration plants obtained from the two screenings as the ecological restoration plants for opencast mining waste land. According to the method of the present invention, ecological restoration herbaceous plants, shrubs and arbors for opencast mining waste land can be screened out, which have the advantages of short screening period, mature screening technology, controllable screening conditions, accurate screening results, etc.

Description

Technical Field

[0001] The present invention relates to the technical field of mine ecological restoration, and particularly to a screening method and application of ecological restoration plants for opencast mining waste land. Background Art

[0002] Open-pit mining, abbreviated as opencast mining, is a process of obtaining target minerals from an open-pit mining site (i.e., an opencast mining area) by removing the overburden on the ore body and stripping the rock and soil. Open-pit mining has advantages such as full utilization of resources, high recovery rate, low dilution rate, suitability for large-scale mechanical construction, fast mine construction, large output, low cost, and production safety. However, it will also have an adverse impact on the mine geological environment. Open-pit mining completely destroys the surface vegetation, forming large areas of bare rock slopes and precipices, causing serious damage to the original land resources and mine geological environment, and greatly affecting the integrity of the surrounding topography and landscape. In production practice, the ecological restoration of opencast mining waste land mainly adopts a combination of stabilization physical measures and phytoremediation methods. Among them, physical measures are generally used for the preliminary treatment of opencast mining areas, and phytoremediation methods are used for the later vegetation restoration. Therefore, the selection of ecological restoration plants is the key work for the ecological restoration of opencast mining waste land.

[0003] At present, the screening methods of ecological restoration plants for opencast mining waste land disclosed in the prior art mainly include: establishing a comprehensive evaluation system by using a hierarchical structure model and a judgment matrix, and screening ecological restoration plants from aspects such as ecological functions, biological characteristics, economic value, and market value; screening by evaluating the correlation between the growth traits and physiological indexes of plants in opencast mining waste land; obtaining the vegetation growth climate environment information and vegetation growth soil information of opencast mining waste land in different altitude regions through aerial photography and soil sampling analysis, and screening ecological restoration plants suitable for different altitudes. However, these methods have a long screening period, imperfect screening technologies, uncontrollable screening links and conditions, and large screening result errors. Summary of the Invention

[0004] The purpose of the present invention is to provide a screening method and application of ecological restoration plants for opencast mining waste land to solve the problems of long screening period, imperfect screening technology, uncontrollable screening links and conditions, and large screening result errors in the prior art.

[0005] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a screening method of ecological restoration plants for opencast mining waste land, including the following steps:

[0007] (1) Measuring the plant biomass and the content of organic acids secreted by roots;

[0008] (2) Preliminarily screening ecological restoration plants according to the measurement results of the plant biomass and the total content of organic acids secreted by roots;

[0009] (3) Calculate the membership function values of the biomass between plant species;

[0010] (4) Calculate the membership function values of the content of organic acids secreted by the roots between plant species, and calculate the average value of the membership function of the content of organic acids secreted by plant roots;

[0011] (5) Calculate the average value of the membership function value of the biomass between plant species and the average value of the membership function of the content of organic acids secreted by plant roots to obtain the total average value, and screen the plants with the total average value ≥ 0.5 to obtain the ecological restoration plants after the second screening;

[0012] (6) Select the overlapping plants from the ecologically restored plants obtained from the preliminary screening and the ecologically restored plants obtained from the second screening to obtain the ecologically restored plants for opencast waste land.

[0013] Preferably, the plants include herbaceous plants, shrubs or trees;

[0014] The types of the herbaceous plants, shrubs or trees are the plants of the opencast waste land.

[0015] Preferably, the method for measuring the biomass of the plants is the drying method;

[0016] The temperature for drying is 70 - 80 °C.

[0017] Preferably, the method for measuring the content of organic acids secreted by the roots is as follows:

[0018] (1) Mix the plant root tips with a methanol solution, crush and centrifuge, and take the supernatant; dry the supernatant to obtain a dry powder; mix the dry powder with an acetonitrile aqueous solution for reconstitution to obtain a test sample;

[0019] (2) Use ultra-high performance liquid chromatography-tandem mass spectrometry to determine the organic acid components and contents in the test sample.

[0020] Preferably, the mass-volume ratio of the plant root tips to the methanol solution is 1 g: 2 - 4 mL;

[0021] The methanol solution is a solution obtained by mixing methanol and formic acid;

[0022] The initial concentration of the methanol is 70 - 80 vt%;

[0023] The initial concentration of the formic acid is 0.05 - 0.15 vt%;

[0024] The volume ratio of the methanol to the formic acid in the mixture is 0.5 - 0.75: 0.25 - 0.5.

[0025] Preferably, the temperature for crushing is -22 - -18 °C;

[0026] The time for crushing is 3 to 5 min;

[0027] The temperature for centrifugation is 2 to 6 °C;

[0028] The rotation speed for centrifugation is 11000 to 13000 rpm;

[0029] The time for centrifugation is 18 to 22 min;

[0030] The drying is freeze-drying;

[0031] The temperature for freeze-drying is -70 to -90 °C;

[0032] The initial concentration of the acetonitrile aqueous solution is 40 to 60 vt%;

[0033] The mass-volume ratio of the dry powder to the acetonitrile aqueous solution for mixing is 0.75 to 1.25 g: 8 to 12 mL.

[0034] Preferably, the chromatographic column for the ultra-high performance liquid chromatography-tandem mass spectrometry is a 2.1×100 mm, 1.8 μm C18 column, mobile phase A is 0.1% formic acid aqueous solution, mobile phase B is 0.1% formic acid acetonitrile, the flow rate is 0.4 mL / min, and the mass-to-charge ratio acquisition range of the ESI ion source is 50 to 1200 Da.

[0035] Preferably, the ecologically restored plants obtained by preliminary screening are ecologically restored herbaceous plants, ecologically restored shrubs or ecologically restored trees;

[0036] The criteria for preliminary screening of ecologically restored herbaceous plants are that the plant biomass > 0.3 g / plant and the total content of organic acids secreted by the roots > 28 mg / g;

[0037] The criteria for preliminary screening of ecologically restored shrubs are that the plant biomass > 1.5 g / plant and the total content of organic acids secreted by the roots > 50 mg / g;

[0038] The criteria for preliminary screening of ecologically restored trees are that the plant biomass > 4.8 g / plant and the total content of organic acids secreted by the roots > 60 mg / g.

[0039] Preferably, the calculation method of the membership function value is: R(X e ) = (X e - X min ) / (X max - X min );

[0040] The R(X e ) is the membership function value, X e is the measured value, X max is the maximum value, and X min is the minimum value;

[0041] The types of the organic acids are one or more of proline, oxalic acid, succinic acid, malic acid, tartaric acid, arginine and lysine.

[0042] The present invention also provides an application of the screening method in screening ecological restoration plants for opencast waste land;

[0043] The ecological restoration plants include herbaceous plants, shrubs or arbors.

[0044] The present invention has the following technical effects and advantages:

[0045] (1) The screening period of the present invention is short, and the screening work is all completed in the laboratory, overcoming the deficiency of the long screening period of the prior art in the open field.

[0046] (2) The screening technology of the present invention is mature, and ordinary laboratory staff can independently complete the technical operation of the present invention.

[0047] (3) The screening result of the present invention is accurate, and the screening links and conditions are all artificially controllable, with small errors. Specific embodiments

[0048] The present invention provides a screening method for ecological restoration plants for opencast waste land, including the following steps:

[0049] (1) Measuring the plant biomass and the content of organic acids secreted by the roots;

[0050] (2) Initially screening the ecological restoration plants according to the measurement results of the plant biomass and the total content of organic acids secreted by the roots;

[0051] (3) Calculating the membership function value of the plant interspecific biomass;

[0052] (4) Calculating the membership function value of the content of organic acids secreted by the roots of plant species and calculating the average value of the membership function of the content of organic acids secreted by the roots of plants;

[0053] (5) Calculating the average value of the membership function value of the plant interspecific biomass and the average value of the membership function of the content of organic acids secreted by the roots of plants to obtain the total average value, and screening the plants with the total average value ≥ 0.5 to obtain the ecological restoration plants after secondary screening;

[0054] (6) Selecting the overlapping plants from the initially screened ecological restoration plants and the secondarily screened ecological restoration plants to obtain the ecological restoration plants for opencast waste land.

[0055] In the present invention, the plants include herbaceous plants, shrubs or arbors, and the types of the herbaceous plants, shrubs or arbors are the plants in the opencast waste land.

[0056] In the present invention, before measuring the plant biomass and the content of organic acids secreted by roots, it also includes seed collection and pot experiments; the seeds are collected from the opencast waste land with natural restored vegetation and are the main plant species in the opencast waste land; the seeds are naturally mature seeds. In the present invention, the pot experiment includes the following steps: sowing the seeds collected from the opencast waste land in a pot for cultivation. The pot is preferably a pot with a diameter of 25 cm × a height of 20 cm, and each pot contains 1 - 3 kg of soil, preferably 2 kg; the soil is the opencast waste land soil taken from the plant seed collection site; in the present invention, the amount of herbaceous plant seeds sown is 20 - 30 seeds / pot, preferably 25 seeds / pot; the amount of shrub seeds sown is 2 - 3 seeds / pot, and the amount of tree seeds sown is 2 - 3 seeds / pot. In the present invention, the light time of the pot experiment is 14 - 18 h / d, preferably 16 h / d; the light intensity of the pot experiment is 2500 - 4500 lux, preferably 3000 lux; the temperature of the pot experiment is 26 - 30 °C, preferably 28 °C; the humidity of the pot experiment is 65 - 70%, preferably 67 - 68%, and more preferably 67.5%. In the present invention, the plant biomass and the content of organic acids secreted by roots can be measured after 25 - 35 days of herbaceous plant potting. In the present invention, the plant biomass and the content of organic acids secreted by roots can be measured after 55 - 65 days of shrub or tree potting.

[0057] In the present invention, the method for measuring the plant biomass is the drying method, the plant biomass is the weight when the whole plant is dried to a constant weight, and the drying temperature is 70 - 80 °C, preferably 72 - 78 °C, and more preferably 75 °C.

[0058] In the present invention, the method for measuring the content of organic acids secreted by roots is as follows:

[0059] (1) Mix the plant root tips with methanol solution, break them, centrifuge, and take the supernatant; dry the supernatant to obtain a dry powder; dissolve the dry powder with an acetonitrile aqueous solution to obtain a sample to be measured;

[0060] (2) Use ultra-high performance liquid chromatography - tandem mass spectrometry to measure the organic acid components and content in the sample to be measured.

[0061] In the present invention, the plant root tips are taken from the fresh roots of potted plants.

[0062] In the present invention, the mass-volume ratio of the plant root tip to the methanol solution is 1 g: 2-4 mL, preferably 1 g: 3 mL. In the present invention, the methanol solution is a solution obtained by mixing methanol and formic acid. The initial concentration of the methanol is 70-80 vt%, preferably 75 vt%, the initial concentration of the formic acid is 0.05-0.15 vt%, preferably 0.1 vt%, and the volume ratio of the methanol to the formic acid is 0.5-0.75: 0.25-0.5, preferably 0.55-0.65: 0.35-0.45, and more preferably 0.6: 0.4.

[0063] In the present invention, the crushing method is to use a high-throughput tissue crusher for crushing. The temperature of the crushing is -22 to -18 °C, preferably -20 °C; the time of the crushing is 3-5 min, preferably 4 min.

[0064] In the present invention, the centrifugation method is cryogenic centrifugation. The temperature of the cryogenic centrifugation is 2-6 °C, preferably 4 °C; the rotation speed of the cryogenic centrifugation is 11000-13000 rpm, preferably 12000 rpm; the time of the cryogenic centrifugation is 18-22 min, preferably 20 min.

[0065] In the present invention, the method for drying the supernatant is freeze-drying, preferably freeze-drying with a freezer. The temperature of the freeze-drying is -70 to -90 °C, preferably -80 °C.

[0066] In the present invention, the initial concentration of the acetonitrile aqueous solution is 40-60 vt%, preferably 50 vt%. In the present invention, the mass-volume ratio of the dry powder to the acetonitrile aqueous solution is 0.75-1.25 g: 8-12 mL, preferably 0.85-1.15 g: 9-11 mL, and more preferably 0.9 g: 10 mL.

[0067] In the present invention, the chromatographic column of the ultra-high performance liquid chromatography-tandem mass spectrometry is a 2.1×100 mm, 1.8 μm C18 column. Mobile phase A is 0.1% formic acid aqueous solution, mobile phase B is 0.1% formic acid acetonitrile, the flow rate is 0.4 mL / min, and the MSe mode is used to collect primary and secondary mass spectrometry data under the control of the acquisition software. At the same time, data is collected for both the positive ion mode and the negative ion mode. The mass-to-charge ratio acquisition range of the ESI ion source is 50-1200 Da.

[0068] In the present invention, ecological restoration plants are preliminarily screened according to the measurement results of plant biomass and the total organic acid content secreted by roots. The preliminarily screened ecological restoration plants are ecological restoration herbaceous plants, ecological restoration shrubs or ecological restoration trees. The criteria for preliminarily screening ecological restoration herbaceous plants are that the plant biomass > 0.3 g / plant and the total organic acid content secreted by roots > 28 mg / g. The criteria for preliminarily screening ecological restoration shrubs are that the plant biomass > 1.5 g / plant and the total organic acid content secreted by roots > 50 mg / g. The criteria for preliminarily screening ecological restoration trees are that the plant biomass > 4.8 g / plant and the total organic acid content secreted by roots > 60 mg / g.

[0069] In the present invention, the average value of the membership function value of the interspecific biomass of plants and the average value of the membership function of the organic acid content secreted by plant roots is calculated to obtain the total average value. Plants with a total average value ≥ 0.5 are screened to obtain the secondarily screened ecological restoration plants. The calculation method of the membership function value is: R(X e ) = (X e - X min ) / (X max - X min ). The R(X e ) is the membership function value, X e is the measured value, X max is the maximum value, X min is the minimum value. The types of the organic acids are one or more of proline, oxalic acid, succinic acid, malic acid, tartaric acid, arginine and lysine.

[0070] The present invention also provides an application of the above screening method in screening ecological restoration plants for opencast mining waste lands. The ecological restoration plants include herbaceous plants, shrubs or trees.

[0071] The technical solutions provided by the present invention will be described in detail below in conjunction with experimental examples, but they should not be construed as limiting the protection scope of the present invention.

[0072] The opencast mining waste land in the embodiment of the present invention is the waste land of Tieshan Iron Mine in Huangshi City.

[0073] Experimental Example 1: Screening of ecological restoration herbaceous plants for opencast mining waste lands

[0074] Mature seeds of 5 species of herbaceous plants, namely tall fescue, imperata cylindrica, bermudagrass, alfalfa and purslane, collected from the opencast mining waste land with natural restored vegetation in the previous year, were placed in a constant temperature culture room for pot experiments.

[0075] The soil from the opencast waste land in the seed collection area was screened, mixed evenly, filled into pots, with 2 kg of soil in each pot. Specifically, 1 kg of soil was filled first, then leveled and compacted, and the remaining 1 kg was filled. The distance between the soil surface and the pot mouth was kept at 3.5 cm, and water was poured to moisten the soil surface and compact the soil mass. Sowing was carried out the next day. The seeding rate of mature seeds of herbaceous plants was 25 seeds per pot, and 1 cm of dry soil was covered after sowing. Water was poured according to the soil moisture condition of the pot before emergence. Thinning was carried out 10 days after emergence, and 15 plants were left in each pot. The experiment was repeated three times, with 5 pots set for each repetition, and a total of 15 pots were planted for each plant. The cultivation conditions were set as follows: the light time was 16 h / d, the light intensity was 3000 lux, the temperature was 28 °C, and the air humidity was 67.5%.

[0076] Thirty days after sowing, 150 plants (10 plants per pot) with consistent growth of each plant were taken, washed clean with tap water, and the root surface was washed 3 times with deionized water. Among them, 75 plants (the whole plant) were placed in an oven, dried to a constant weight at 75 °C and weighed, which was the plant biomass; for the other 75 plants, 1 g of the root tip mixed sample of each plant was mixed with 3 mL of methanol solution (prepared by mixing 75 vt% methanol and 0.1% vt formic acid in a volume ratio of 0.6:0.4), and then crushed at -20 °C for 4 min using a high-throughput tissue crusher. After that, at 4 °C, it was centrifuged at 12,000 rpm for 20 min, and the supernatant was taken and frozen into dry powder using a freeze dryer. The temperature of freeze drying was -80 °C. Then, it was redissolved with pre-cooled 50 vt% acetonitrile aqueous solution (the mass-volume ratio of the dry powder to the acetonitrile aqueous solution was 0.9 g:10 mL), and the above steps were repeated to obtain the sample to be measured. The organic acid components and their contents in the sample to be measured were determined by ultra-high performance liquid chromatography-tandem mass spectrometry. The chromatographic conditions were set as follows: the chromatographic column was a 2.1×100 mm, 1.8 μm C18 column, the mobile phase A was 0.1% formic acid aqueous solution, the mobile phase B was 0.1% formic acid acetonitrile, the flow rate was 0.4 mL / min, and the MSe mode under the control of the acquisition software was used to collect the first-level and second-level mass spectrometry data, and the data were collected for both the positive ion mode and the negative ion mode at the same time. The mass-to-charge ratio acquisition range of the ESI ion source was 50 - 1200 Da. The types of organic acids were proline, oxalic acid, succinic acid, malic acid, tartaric acid, arginine, and lysine.

[0077] The measurement results of the biomass of herbaceous plants are shown in Table 1, and the measurement results of the content of organic acids secreted by the roots of herbaceous plants are shown in Table 2. According to the biomass of each herbaceous plant, the membership function value of the interspecific biomass of herbaceous plants was calculated. The calculation method of the membership function value was: R(X e )=(X e -X min ) / (X max -X min ), where R(X e ) was the membership function value, Xe is the measured value, X max is the maximum value, X min is the minimum value. As shown in Table 3. Calculate the membership function value of the content of organic acids secreted by the roots of herbaceous plants among different species according to the content of organic acids secreted by the roots of herbaceous plants, calculate the average value of the membership function of the content of organic acids secreted by each herbaceous plant, and then calculate the average value of the membership function value of plant biomass and the average value of the membership function of the content of organic acids secreted by the roots to obtain the total average value. The results are shown in Table 3.

[0078] Table 1 Biomass of Herbaceous Plants

[0079] Plant species Festuca arundinacea Imperata cylindrica Cynodon dactylon Medicago sativa Portulaca oleracea Biomass (g / plant) 0.587 0.453 0.516 0.342 0.238

[0080] Table 2 Content of Organic Acids Secreted by the Roots of Herbaceous Plants

[0081]

[0082]

[0083] Table 3 Membership Function Values of Biomass and Organic Acids Secreted by the Roots of Herbaceous Plants

[0084]

[0085] Tables 1 - 3 show that the plant biomass of the 5 tested herbaceous plants from high to low is Festuca arundinacea, Cynodon dactylon, Imperata cylindrica, Medicago sativa, and Portulaca oleracea; taking plant biomass > 0.3 g / plant and the total content of organic acids secreted by the roots > 28 mg / g as the preliminary screening criteria for herbaceous plants for ecological restoration of opencast mine waste lands, the herbaceous plants meeting the preliminary screening criteria include Festuca arundinacea, Imperata cylindrica, Cynodon dactylon, and Medicago sativa.

[0086] Taking the total average value ≥ 0.5 as the secondary screening criteria for herbaceous plants for ecological restoration of opencast mine waste lands, the herbaceous plants obtained by secondary screening include Festuca arundinacea, Cynodon dactylon, and Imperata cylindrica. The herbaceous plants obtained by preliminary screening coincide with those obtained by secondary screening. Select the herbaceous plants that coincide in both screenings to obtain the herbaceous plants for ecological restoration of opencast mine waste lands. The finally selected herbaceous plants for ecological restoration are Festuca arundinacea, Cynodon dactylon, and Imperata cylindrica.

[0087] Example 2: Screening of Woody Plants for Ecological Restoration of Opencast Mine Waste Lands

[0088] Use the mature seeds of 6 woody plants (including 3 shrubs and 3 trees), Indigofera pseudotinctoria, Lespedeza bicolor, Ligustrum quihoui, Broussonetia papyrifera, Robinia pseudoacacia, and Pinus massoniana, collected from the opencast mine waste lands with natural restored vegetation in the previous year, and conduct pot experiments in a constant temperature culture room.

[0089] The soil from the opencast waste land in the seed collection area was screened, mixed evenly, filled into pots, with 2 kg of soil in each pot. Specifically, first fill 1 kg, spread it flat and compact it, then fill the remaining 1 kg. Keep the distance between the soil surface and the pot mouth at 3.5 cm, water to make the soil surface moist and the soil mass settle, and sow seeds the next day. The sowing rate of mature seeds of shrubs or trees is 3 seeds per pot. After sowing, cover with 3 cm of dry soil. Water according to the soil moisture condition of the pot before emergence. Thin the seedlings 10 days after emergence, leaving 1 seedling per pot. The experiment was repeated three times, with 5 pots set for each repetition, and a total of 15 pots were planted for each plant. Set the cultivation conditions as follows: light time is 16 h / d, light intensity is 3000 lux, temperature is 28 °C, and air humidity is 67.5%.

[0090] After 60 days of sowing, 15 plants (1 plant per pot) with consistent growth of each plant were taken, washed clean with tap water, and the root surface was washed 3 times with deionized water. Take 1 g of the root tip mixed sample of each plant for standby. Then place the whole plant in an oven, dry it at 75 °C to constant weight and weigh it, which is the plant biomass. Mix 1 g of the root tip mixed sample with 3 mL of methanol solution (prepared by mixing 75 vt% methanol and 0.1% vt formic acid in a volume ratio of 0.6:0.4), and then use a high-throughput tissue crusher to crush it at -20 °C for 4 min. After that, centrifuge it at 12,000 rpm at 4 °C for 20 min, take the supernatant and freeze-dry it into dry powder with a freeze dryer at -80 °C. Then dissolve it with pre-cooled 50 vt% acetonitrile aqueous solution (the mass-volume ratio of dry powder to acetonitrile aqueous solution is 0.9 g:10 mL), and repeat the above steps to obtain the sample to be measured. Determine the organic acid components and their contents in the sample by ultra-high performance liquid chromatography-tandem mass spectrometry. Set the chromatographic conditions as follows: the chromatographic column is 2.1×100 mm, 1.8 μm C18 column, mobile phase A is 0.1% formic acid aqueous solution, mobile phase B is 0.1% formic acid acetonitrile, the flow rate is 0.4 mL / min, and the MSe mode under the control of the acquisition software is used to collect the first-level and second-level mass spectrometry data, and the data is collected for both the positive ion mode and the negative ion mode at the same time. The mass-to-charge ratio acquisition range of the ESI ion source is 50 - 1200 Da. The types of organic acids are proline, oxalic acid, succinic acid, malic acid, tartaric acid, arginine, and lysine.

[0091] The measurement results of the biomass of shrubs and trees are shown in Table 4, and the measurement results of the content of organic acids secreted by the roots of shrubs and trees are shown in Table 5. Calculate the membership function values of the interspecific biomass of shrubs and trees according to the biomass of each plant of shrubs and trees. The calculation method of the membership function value is: R(X e )=(X e -X min ) / (X max -X min ), where R(X e ) is the membership function value, Xe is the measured value, X max is the maximum value, X min is the minimum value. As shown in Table 6. Calculate the membership function values of the organic acid content secreted by the roots of shrubs and arbors in the interspecific roots of shrubs and arbors according to the organic acid content secreted by the roots of shrubs and arbors, then calculate the average membership function values of the organic acid content secreted by the roots of each shrub and arbor, and then calculate the average value of the membership function value of plant biomass and the average membership function value of the organic acid content secreted by the roots to obtain the total average value, as shown in Table 6.

[0092] Table 4 Biomass of Shrubs and Arbors

[0093]

[0094] Table 5 Organic Acid Content Secreted by the Roots of Shrubs and Arbors

[0095]

[0096] Table 6 Membership Function Values of Biomass and Organic Acid Index Secreted by the Roots of Shrubs and Arbors

[0097]

[0098] Tables 4 - 6 show that the plant biomass of the three tested shrubs from high to low is Lespedeza bicolor, Indigofera pseudotinctoria, and Ligustrum quihoui. Taking plant biomass > 1.5 g / plant and the total organic acid content secreted by the roots > 50 mg / g as the preliminary screening criteria for shrubs in the ecological restoration of opencast mine waste land, the shrubs that meet the preliminary screening criteria include Indigofera pseudotinctoria and Lespedeza bicolor; the plant biomass of the three tested arbors from high to low is Broussonetia papyrifera, Robinia pseudoacacia, and Pinus massoniana; taking plant biomass > 4.8 g / plant and the total organic acid content secreted by the roots > 60 mg / g as the preliminary screening criteria for arbors in the ecological restoration of opencast mine waste land, the arbors that meet the preliminary screening criteria include Broussonetia papyrifera and Robinia pseudoacacia.

[0099] Taking the total average value ≥ 0.5 as the secondary screening criteria for shrubs and arbors in the ecological restoration of opencast mine waste land, the shrubs obtained by secondary screening are Indigofera pseudotinctoria and Lespedeza bicolor, and the arbors are Broussonetia papyrifera and Robinia pseudoacacia. The shrubs and arbors obtained by preliminary screening coincide with the shrubs and arbors obtained by secondary screening. Select the shrubs and arbors that coincide in the two screenings to obtain the ecological restoration plants for opencast mine waste land. The finally selected ecological restoration shrubs are Indigofera pseudotinctoria and Lespedeza bicolor, and the ecological restoration arbors are Broussonetia papyrifera and Robinia pseudoacacia.

[0100] Example 3: Comprehensive Evaluation of the Restoration Effect of Ecological Restoration Plants on Opencast Mine Waste Land

[0101] The selected opencast waste land for the restoration experiment is the waste land of Tieshan Iron Mine in Huangshi City, with a slope of 28°, an altitude of 235 m, and the surface soil is slag accumulated over the years. The soil pH value is 4.5 - 6.5, mainly sandy in texture, with poor water and fertilizer retention capacity, poor nutrients, and extremely low organic matter content, only 0.35 g / kg. In addition to a relatively high content of Fe in the soil, the contents of mineral elements such as S, Si, and Cu are also relatively high, which are 12.37 g / kg, 4.37 g / kg, and 0.34 g / kg respectively.

[0102] The restoration experiment adopted a randomized block design. Ecological restoration herbaceous plants such as tall fescue, bermudagrass, and imperata cylindrica screened in Example 1, ecological restoration shrubs such as indigofera pseudotinctoria and lespedeza bicolor screened in Example 2, and ecological restoration arbors such as Broussonetia papyrifera and Robinia pseudoacacia were used to restore the opencast waste land, and alfalfa, privet, and masson pine were used as control plants for ecological restoration herbaceous plants, ecological restoration shrubs, and ecological restoration arbors respectively. In March 2022, ecological restoration plant planting plots were opened along the slope direction of the opencast waste land. Among them, the area of the ecological restoration herbaceous plant planting plot was set to 40 m 2 (5 m × 8 m). Each planting plot was planted with 40 holes, and each hole was planted with 3 ecological restoration herbaceous plants; the ecological restoration woody plants were planted in 3 rows, with 40 plants in each row, and the planting spacing was 1.5 m × 1.5 m. In September 2022, the survival numbers, average new tillers, and plant height growth amounts of ecological restoration herbaceous plants and control plants, as well as the survival numbers, plant heights, ground diameters, and crown width growth amounts of ecological restoration woody plants and control plants and other ecological restoration indicators were counted, and the average survival rate and restoration effect of ecological restoration plants were calculated. The results are shown in Table 7:

[0103]

[0104]

[0105] Table 7 Restoration effects of ecological restoration plants on opencast waste land

[0106]

[0107] Table 7 shows that compared with the control plants, the average survival rate, average new tiller number and plant height growth of the ecological restoration herbaceous plants increased by 57.9%, 83.3% and 22.8% respectively; the average survival rate, plant height, ground diameter and crown width growth of the ecological restoration shrubs increased by 34.5%, 90.7%, 29.4% and 78.5% respectively, and the average survival rate, plant height, ground diameter and crown width growth of the ecological restoration arbor increased by 37.4%, 71.4%, 60.5% and 57.3% respectively; the average survival rate, plant height, ground diameter and crown width growth of the ecological restoration woody plants increased by 42.5%, 81.1%, 44.9% and 67.9% respectively. It can be seen that the ecological restoration plants screened by the present invention have very obvious ecological restoration effects on the opencast mining waste land.

[0108] As can be seen from the above embodiments, the present invention provides a screening method and application of ecological restoration plants for opencast mining waste land. The ecological restoration herbaceous plants for opencast mining waste land screened by the method of the present invention are Festuca elata, Cynodon dactylon and Imperata cylindrica, the ecological restoration shrubs are Indigofera pseudotinctoria and Lespedeza bicolor, and the ecological restoration arbors are Broussonetia papyrifera and Robinia pseudoacacia, which have the advantages of short screening period, mature screening technology, controllable screening conditions, accurate screening results and very obvious ecological restoration effects on the opencast mining waste land.

[0109] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A screening method for ecological restoration plants in opencast mining waste land, characterized in that, it includes the following steps: (1) Measure the plant biomass and the content of organic acids secreted by the roots; (2) Initially screen ecological restoration plants based on the measurement results of plant biomass and the total content of organic acids secreted by the roots; (3) Calculate the membership function value of the interspecific biomass of plants; (4) Calculate the membership function value of the content of organic acids secreted by the roots among plant species, and calculate the average value of the membership function of the content of organic acids secreted by the plant roots; (5) Calculate the average value of the membership function value of the interspecific biomass of plants and the average value of the membership function of the content of organic acids secreted by the plant roots to obtain the total average value, and screen plants with a total average value ≥ 0.5 to obtain the secondarily screened ecological restoration plants; (6) Select the overlapping plants from the initially screened ecological restoration plants and the secondarily screened ecological restoration plants to obtain the ecological restoration plants in opencast mining waste land; The initially screened ecological restoration plants are ecological restoration herbaceous plants, ecological restoration shrubs or ecological restoration trees; The criteria for initially screening ecological restoration herbaceous plants are that the plant biomass > 0.3 g / plant and the total content of organic acids secreted by the roots > 28 mg / g; The criteria for initially screening ecological restoration shrubs are that the plant biomass > 1.5 g / plant and the total content of organic acids secreted by the roots > 50 mg / g; The criteria for initially screening ecological restoration trees are that the plant biomass > 4.8 g / plant and the total content of organic acids secreted by the roots > 60 mg / g; The calculation method of the membership function value is: R(X e )=(X e −X min ) / (X max −X min ); The membership function value of R(X e ) is R(X e ), where X max is the measured value, X min is the maximum value, and X min is the minimum value; The types of the organic acids are one or more of proline, oxalic acid, succinic acid, malic acid, tartaric acid, arginine and lysine.

2. The screening method according to claim 1, characterized in that, the plants include herbaceous plants, shrubs or trees; The types of the herbaceous plants, shrubs or trees are the plants in opencast mining waste land.

3. The screening method according to claim 2, characterized in that, The method for measuring the plant biomass is the drying method; The temperature for drying is 70 - 80 °C.

4. The screening method according to claim 3, characterized in that, The method for measuring the content of organic acids secreted by the roots is: (1) Mix the plant root tips with a methanol solution, break them, centrifuge, and take the supernatant; dry the supernatant to obtain a dry powder; mix the dry powder with an acetonitrile aqueous solution for reconstitution to obtain a sample to be measured; (2) Use ultra-high performance liquid chromatography - tandem mass spectrometry to measure the organic acid components and contents in the sample to be measured.

5. The screening method according to claim 4, characterized in that, The mass - volume ratio of the plant root tips to the methanol solution for mixing is 1 g:2 - 4 mL; The methanol solution is a solution obtained by mixing methanol and formic acid; The initial concentration of the methanol is 70 - 80 vt%; The initial concentration of the formic acid is 0.05 - 0.15 vt%; The volume ratio of the methanol to the formic acid for mixing is 0.5 - 0.75:0.25 - 0.

5.

6. The screening method according to claim 5, characterized in that, The temperature for breaking is - 22 - - 18 °C; The time for breaking is 3 - 5 min; The temperature for centrifuging is 2 - 6 °C; The rotation speed of the centrifugation is 11,000 - 13,000 rpm; The time of the centrifugation is 18 - 22 min; The drying is freeze-drying; The temperature of the freeze-drying is -70 to -90 °C; The initial concentration of the acetonitrile aqueous solution is 40 - 60 vt%; The mass-volume ratio of the dry powder to the acetonitrile aqueous solution for mixing is 0.75 - 1.25 g:8 - 12 mL.

7. The screening method according to claim 6, characterized in that the chromatographic column of the ultra-high performance liquid chromatography-tandem mass spectrometry is a 2.1×100 mm, 1.8 μm C18 column, mobile phase A is 0.1% formic acid aqueous solution, mobile phase B is 0.1% formic acid acetonitrile, the flow rate is 0.4 mL / min, and the mass-to-charge ratio acquisition range of the ESI ion source is 50 - 1200 Da.

8. Use of the screening method according to any one of claims 1 to 7 in screening ecological restoration plants for opencast mining waste land; The ecological restoration plants include herbaceous plants, shrubs or trees.

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