Method for improving uranium-contaminated soil phytoremediation efficiency by utilizing plant rhizosphere release behavior
By planting uranium hyperaccumulator plants in uranium-contaminated soil and using the plant rhizosphere release behavior for regular harvesting, the problems of low efficiency, long cycle and high cost of remediating uranium-contaminated soil in the existing technology are solved, and an efficient and environmentally friendly method is achieved. soil remediation effect.
Patent Information
- Application Number
- CN202411856930.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-01-21
AI Technical Summary
Existing phytoremediation technologies are inefficient in treating uranium-contaminated soil, have long cycles, and are costly, making it difficult to effectively remove uranium from the soil.
By selecting uranium super -rich plants, the time nodes of the time node of plants to release uranium pollution soils are planted in uranium pollution soil for harvesting, repeated planting and regular harvesting, and use plant root release behaviors to improve uranium absorption and enrichment capabilities.
It significantly improves the ability of plants to absorb and enrich uranium, shortens the soil remediation cycle, accelerates the purification process of uranium-contaminated soil, reduces remediation costs, and achieves efficient and environmentally friendly soil remediation.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of phytoremediation of uranium-contaminated soil, and in particular relates to a method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior. Background Art
[0002] Uranium mining and smelting activities are widely carried out around the world, producing a large amount of uranium-contaminated soil, posing a serious potential threat to the health of surrounding residents and the ecological environment. As the uranium pollution problem becomes increasingly serious, the remediation of uranium-contaminated soil has become urgent. At present, the remediation technologies for uranium-contaminated soil mainly include physical methods, chemical methods and biological methods. Among these methods, phytoremediation technology has attracted widespread attention due to its advantages such as environmental friendliness, low cost and simple operation.
[0003] Phytoremediation technology involves using plants and their associated microorganisms to transfer uranium in the soil to the roots, stems and leaves of the plants, thereby achieving soil purification. However, existing phytoremediation technologies have problems of low efficiency and long cycles when treating uranium-contaminated soil. Due to the limitations of plant growth cycles and the slow migration of uranium in the soil, the phytoremediation process may take years or even decades. In addition, plants have limited ability to accumulate uranium, and some plants have low enrichment coefficients for uranium, making it difficult to efficiently remove uranium from the soil. Therefore, in practical applications, phytoremediation technology usually needs to be combined with other remediation technologies to improve remediation efficiency. Although there have been many methods to try to improve the efficiency of phytoremediation of uranium-contaminated soil, such as screening and cultivating plant species with high accumulation capacity, optimizing soil conditions, applying rhizosphere microorganisms, adding chemical chelators, plant rotation and intercropping, and combining plants with physical or chemical remediation technologies, the application of these methods often increases the cost of phytoremediation. Therefore, developing a method that can both improve the efficiency of phytoremediation and reduce costs has become a technical problem that needs to be solved urgently in this field. Summary of the invention
[0004] The present invention aims to provide a method for improving the efficiency of phytoremediation of uranium contaminated soil by utilizing plant rhizosphere release behavior. The method not only improves the efficiency of phytoremediation of uranium contaminated soil, but also shortens the remediation cycle, reduces the remediation cost, and realizes efficient and environmentally friendly remediation of uranium contaminated soil.
[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: A method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior comprises the following steps: S1. Select seeds or seedlings of uranium hyperaccumulating plants for germination and cultivation. Soak the seeds of uranium hyperaccumulating plants in warm water at 60°C for 2-3 hours, dry naturally, sow them in the soil, germinate naturally, and plant cuttings of uranium hyperaccumulating plant seedlings in the soil, and water them regularly. S2. Transplantation: After the uranium hyperaccumulator plants have grown for a period of time, their seedlings are transplanted into uranium-contaminated soil and watered regularly; S3. Harvesting of uranium hyperaccumulating plants: When the uranium hyperaccumulating plants grow naturally or add chelating agents to enhance the rhizosphere release behavior, harvest the above-ground and underground parts of the plants and measure the uranium enrichment; S4. Repeated planting and harvesting of uranium hyper-enriched plants: After the above-ground and underground parts of the uranium hyper-enriched plants are harvested for the first time, the new uranium hyper-enriched plant seedlings obtained in step S2 are transplanted into uranium-contaminated soil. When the rhizosphere release behavior occurs naturally or after the addition of chelating agents, the above-ground and underground parts of the uranium hyper-enriched plants are harvested to determine the uranium enrichment amount.
[0006] Preferably, the uranium hyperaccumulating plants include one or more of Macleaya cordata, Commelina scabra and Salix babylonica.
[0007] Preferably, in step S1, the specific method of sowing is: sowing 300-500 seeds or 2000-4000 seeds per square meter, and the sowing thickness is 5-10 cm; the specific method of the seedling branch cuttings is: cut a section of the seedling branch with 8 leaves, 18 cm long, retain two leaves on each of the top 4 leaves, and cut the bottom 4 leaves from the petiole, insert the cut seedling branch into the soil 8 cm, and retain 10 cm of branches with leaves outside.
[0008] Preferably, in step S2, 28-60 days after the uranium hyperaccumulating plant seeds germinate and grow the first leaf, or 20 days after the uranium hyperaccumulating plant seedlings and branches grow new leaves, the seedlings are transplanted into uranium-contaminated soil.
[0009] Preferably, in step S3, the chelating agent comprises one or both of oxalic acid and iron carrier.
[0010] Preferably, the iron carrier is deferoxamine mesylate.
[0011] Preferably, in step S3, under natural growth conditions, uranium hyperaccumulator plant seedlings are transplanted into uranium-contaminated soil for 14-63 days before uranium rhizosphere release occurs, and the above-ground and underground parts of the plants are harvested to measure uranium enrichment.
[0012] Preferably, in step S3, when a chelating agent is added, oxalic acid is added to the rhizosphere soil of the uranium hyperaccumulating plants 6-12 days after the uranium hyperaccumulating plant seedlings are transplanted into the uranium contaminated soil, and on the 9th to 15th day, iron carriers are added to the rhizosphere soil of the uranium hyperaccumulating plants. After the 12th to 18th day, the uranium hyperaccumulating plant seedlings show uranium rhizosphere release behavior, and the above-ground and underground parts of the plants are harvested to determine the uranium enrichment.
[0013] Preferably, in step S4, under natural growth conditions, after the above-ground and underground parts of the uranium hyper-enriched plants are harvested for the first time, the new uranium hyper-enriched plant seedlings obtained in step S2 are transplanted in uranium-contaminated soil, and harvested again after 14-63 days. Transplantation and harvesting are performed every 14-63 days, and this cycle is repeated to determine the uranium enrichment amount.
[0014] Preferably, in step S4, when a chelating agent is added, after the above-ground and underground parts of the uranium hyperaccumulating plant are harvested for the first time, the new uranium hyperaccumulating plant seedlings obtained in step S2 are transplanted into the uranium contaminated soil. 6-12 days after the uranium hyperaccumulating plant seedlings are transplanted into the uranium contaminated soil, oxalic acid is added to the rhizosphere soil of the uranium hyperaccumulating plant. On the 9th to 15th day, iron carriers are added to the rhizosphere soil of the uranium hyperaccumulating plant. After the 12th to 18th day, uranium rhizosphere release behavior occurs, and the above-ground and underground parts of the plant are harvested, and the cycle is repeated to determine the uranium enrichment amount.
[0015] Compared with the prior art, the present invention has the following advantages and technical effects: (1) By planting hyperaccumulator plants in uranium-contaminated soil and harvesting them at the precise timing of uranium release from the plant rhizosphere, the present invention significantly improves the plant's ability to absorb and accumulate uranium, thereby increasing the efficiency of soil remediation.
[0016] (2) Compared with traditional phytoremediation methods, the present invention effectively shortens the entire soil remediation cycle and accelerates the purification process of uranium-contaminated soil through the strategy of repeated planting and regular harvesting.
[0017] (3) By precisely controlling the occurrence time and harvest time of uranium release from the plant rhizosphere, the present invention ensures efficient uranium enrichment, maximizes the effect of phytoremediation, and achieves efficient and environmentally friendly remediation of uranium-contaminated soil.
[0018] In summary, the method disclosed in the present invention utilizes plant rhizosphere release behavior to improve the efficiency of phytoremediation of uranium contaminated soil, which not only improves the efficiency of phytoremediation of uranium contaminated soil, shortens the remediation period, and reduces costs, but also has low environmental risks in the entire process. It is an efficient, environmentally friendly and sustainable soil remediation technology.
[0019] The technical solution of the present invention is further described in detail below through embodiments. DETAILED DESCRIPTION
[0020] The technical solution of the present invention is further illustrated by the following embodiments.
[0021] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.
[0022] In the present invention, unless otherwise specified, other test materials and instruments and equipment are conventional test materials in the art and can be purchased through commercial channels.
[0023] Example 1 This example provides a method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, comprising the following steps: S1. Select seeds of Macleaya oleifera and soak them in warm water at 60℃ for 3h, air dry them naturally, sow them on the soil at a thickness of 10cm at a rate of 3000 seeds per square meter, germinate them naturally, and water them regularly every day; S2. Transplantation: 60 days after the first leaf of the seeds of Macleaya oleifera germinated, transplant the Macleaya oleifera seedlings into 30 mg / kg uranium-contaminated soil and water them regularly every day. S3. Harvesting of uranium hyperaccumulating plants: Under natural growth conditions, 14 days after the Macleaya hirta seedlings were transplanted into uranium-contaminated soil, uranium rhizosphere release behavior appeared. The above-ground and underground parts of the plants were harvested to measure the uranium enrichment. S4. Repeated planting and harvesting of uranium hyperaccumulating plants: Under natural growth conditions, after the first harvest of the above-ground and underground parts of Macleaya rubra, the new Macleaya rubra seedlings obtained in step S2 are transplanted into uranium-contaminated soil. The seedlings are harvested again after 14 days, and the uranium content in the above-ground and underground parts is measured. Transplantation and harvesting are performed every 14 days, and this cycle is repeated to gradually reduce the uranium content in the soil.
[0024] Example 2 This example provides a method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, comprising the following steps: S1. Select seeds of Macleaya oleifera and soak them in warm water at 60℃ for 3h, air dry them naturally, sow them on the soil at a thickness of 10cm at a rate of 3000 seeds per square meter, germinate them naturally, and water them regularly every day; S2. Transplantation: 60 days after the first leaf of the seeds of Macleaya oleifera germinated, transplant the Macleaya oleifera seedlings into 30 mg / kg uranium-contaminated soil and water them regularly every day. S3. Harvesting of uranium hyperaccumulators: When chelating agents were added, 10 mmol / L oxalic acid was added to the rhizosphere soil 6 days after the Macleaya seedlings were transplanted into the uranium-contaminated soil, so that the concentration of oxalic acid in the soil reached 2 mmol / kg. On the 9th day, 1 mmol / L deferoxamine mesylate was added to the rhizosphere soil, so that the concentration of iron carriers in the soil reached 0.1 mmol / kg. 12 days after the Macleaya seedlings were transplanted into the uranium-contaminated soil, uranium rhizosphere release behavior occurred, and the above-ground and underground parts of the plants were harvested to determine the uranium enrichment. S4. Repeated planting and harvesting of uranium hyperaccumulators: When a chelating agent is added, after the above-ground and underground parts of Macleaya oleifera are harvested for the first time, new Macleaya oleifera seedlings obtained in step S2 are transplanted into uranium-contaminated soil. Six days after the Macleaya oleifera seedlings are transplanted into the uranium-contaminated soil, 10 mmol / L oxalic acid is added to the rhizosphere soil to make the concentration of oxalic acid in the soil reach 2 mmol / kg. On the ninth day, 1 mmol / L iron carrier is added to the rhizosphere soil to make the concentration of iron carrier in the soil reach 0.1 mmol / kg. Twelve days after the Macleaya oleifera seedlings are transplanted into the uranium-contaminated soil, uranium rhizosphere release behavior occurs, and the above-ground and underground parts of the plants are harvested. This cycle is repeated to determine the uranium enrichment amount and gradually reduce the uranium content in the soil.
[0025] Example 3 This example provides a method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, comprising the following steps: S1. Soak the seeds of Duckweed in warm water at 60℃ for 3h, air dry naturally, and sow 500 seeds of Duckweed per square meter on the soil to a thickness of 10 cm. Germination is allowed to take place naturally, and watering is carried out regularly every day. S2. Transplantation: 28 days after the first leaf of the coleopterus seeds germinate, transplant the coleopterus seedlings into 30 mg / kg uranium-contaminated soil and water them regularly every day; S3. Harvesting of uranium hyperaccumulating plants: Under natural growth conditions, 49 days after the young coleus seedlings were transplanted into uranium-contaminated soil, uranium rhizosphere release occurred. The above-ground and underground parts of the plants were harvested to measure the uranium enrichment. S4. Repeated planting and harvesting of uranium hyperaccumulating plants: Under natural growth conditions, after the first harvest of the above-ground and underground parts of the spatholobi, the new spatholobi seedlings obtained in step S2 are transplanted into the uranium-contaminated soil. The seedlings are harvested again after 49 days, and the uranium content in the above-ground and underground parts is measured. The transplanting and harvesting are performed every 49 days, and this cycle is repeated to gradually reduce the uranium content in the soil.
[0026] Example 4 This example provides a method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, comprising the following steps: S1. Soak the seeds of Coleus edulis in warm water at 60℃ for 3h, air dry naturally, and sow them on the soil at a thickness of 10 cm at a rate of 300 seeds per square meter. Allow them to germinate naturally and water them regularly every day. S2. Transplantation: 28 days after the first leaf of the coleopterus seeds germinate, transplant the coleopterus seedlings into 30 mg / kg uranium-contaminated soil and water them regularly every day; S3. Harvesting of uranium hyperaccumulators: When chelating agents were added, 8 days after the spathodea seedlings were transplanted into the uranium-contaminated soil, 10 mmol / L oxalic acid was added to the rhizosphere soil to make the oxalic acid concentration in the soil reach 2 mmol / kg. On the 11th day, 1 mmol / L deferoxamine mesylate was added to the rhizosphere soil to make the iron carrier concentration in the soil reach 0.1 mmol / kg. 14 days after the spathodea seedlings were transplanted into the uranium-contaminated soil, uranium rhizosphere release behavior occurred. The above-ground and underground parts of the plants were harvested to measure the uranium enrichment. S4. Repeated planting and harvesting of uranium hyperaccumulators: When a chelating agent is added, after the above-ground and underground parts of the spatholobi are harvested for the first time, the new spatholobi seedlings obtained in step S2 are transplanted into the uranium-contaminated soil. Eight days after the spatholobi seedlings are transplanted into the uranium-contaminated soil, 10 mmol / L oxalic acid is added to the rhizosphere soil to make the oxalic acid concentration in the soil reach 2 mmol / kg. On the 11th day, 1 mmol / L iron carrier is added to the rhizosphere soil to make the iron carrier concentration in the soil reach 0.1 mmol / kg. 14 days after the spatholobi seedlings are transplanted into the uranium-contaminated soil, uranium rhizosphere release behavior occurs, and the above-ground and underground parts of the plants are harvested. This cycle is repeated to determine the uranium enrichment amount and gradually reduce the uranium content in the soil.
[0027] Example 5 This example provides a method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, comprising the following steps: S1. Select bamboo willow branches, cut a section of seedling branches with 8 leaves, 18 cm long, keep two leaves on each of the top 4 leaves, cut off the bottom 4 leaves from the petiole, insert the cut seedling branches into the soil for 8 cm, keep 10 cm branches with leaves outside, and water regularly every day; S2. Transplantation: 20 days after the bamboo willow seedlings grow new leaves, transplant them into 30 mg / kg uranium-contaminated soil and water them regularly every day; S3. Harvesting of uranium hyperaccumulating plants: Under natural growth conditions, uranium rhizosphere release occurs 63 days after bamboo and willow seedlings are transplanted into uranium-contaminated soil. The above-ground and underground parts of the plants are harvested to measure uranium enrichment. S4. Repeated planting and harvesting of uranium hyper-enriched plants: Under natural growth conditions, after the first harvest of the above-ground and underground parts of the bamboo willow, the new bamboo willow seedlings obtained in step S2 are transplanted into the uranium-contaminated soil. The seedlings are harvested again after 63 days, and the uranium content in the above-ground and underground parts is measured. Transplantation and harvesting are performed every 63 days, and this cycle is repeated to gradually reduce the uranium content in the soil.
[0028] Example 6 This example provides a method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, comprising the following steps: S1. Select bamboo willow branches, cut a section of seedling branches with 8 leaves, 18 cm long, keep two leaves on each of the top 4 leaves, cut off the bottom 4 leaves from the petiole, insert the cut seedling branches into the soil for 8 cm, keep 10 cm branches with leaves outside, and water regularly every day; S2. Transplantation: 20 days after the bamboo willow seedlings grow new leaves, transplant them into 30 mg / kg uranium-contaminated soil and water them regularly every day; S3. Harvesting of uranium hyperaccumulators: When chelating agents were added, 10 mmol / L oxalic acid was added to the rhizosphere soil 12 days after the bamboo and willow seedlings were transplanted into the uranium-contaminated soil, so that the concentration of oxalic acid in the soil reached 2 mmol / kg. On the 15th day, 1 mmol / L deferoxamine mesylate was added to the rhizosphere soil, so that the concentration of iron carriers in the soil reached 0.1 mmol / kg. 18 days after the bamboo and willow seedlings were transplanted into the uranium-contaminated soil, uranium rhizosphere release behavior occurred, and the above-ground and underground parts of the plants were harvested to determine the uranium enrichment. S4. Repeated planting and harvesting of uranium hyperaccumulators: When a chelating agent is added, after the above-ground and underground parts of the bamboo willow are harvested for the first time, the new bamboo willow seedlings obtained in step S2 are transplanted into the uranium-contaminated soil. 12 days after the bamboo willow seedlings are transplanted into the uranium-contaminated soil, 10 mmol / L oxalic acid is added to the rhizosphere soil to make the oxalic acid concentration in the soil reach 2 mmol / kg. On the 15th day, 1 mmol / L iron carrier is added to the rhizosphere soil to make the iron carrier concentration in the soil reach 0.1 mmol / kg. 18 days after the bamboo willow seedlings are transplanted into the uranium-contaminated soil, uranium rhizosphere release behavior occurs, and the above-ground and underground parts of the plants are harvested. This cycle is repeated to determine the uranium enrichment amount and gradually reduce the uranium content in the soil.
[0029] Comparative Example 1 This comparative example has the same steps as the method provided in Example 1 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, except that the Macleaya seedlings are transplanted into the growth cycle of the uranium-contaminated soil and the Macleaya seedlings are harvested only once.
[0030] Comparative Example 2 This comparative example has the same steps as the method provided in Example 2 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, except that the Macleaya seedlings are transplanted into the growth cycle of the uranium-contaminated soil and the Macleaya seedlings are harvested only once.
[0031] Comparative Example 3 This comparative example has the same steps as the method provided in Example 3 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, the difference being that the coleus seedlings are transplanted into the growth cycle of the uranium-contaminated soil and the coleus is harvested only once.
[0032] Comparative Example 4 This comparative example has the same steps as the method provided in Example 4 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, the difference being that the coleus seedlings are transplanted into the growth cycle of the uranium-contaminated soil and the coleus is harvested only once.
[0033] Comparative Example 5 This comparative example has the same steps as the method provided in Example 5 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, except that the bamboo willow seedlings are transplanted into the growth cycle of the uranium-contaminated soil and the bamboo willows are harvested only once.
[0034] Comparative Example 6 This comparative example has the same steps as the method provided in Example 6 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, except that the bamboo willow seedlings are transplanted into the growth cycle of the uranium-contaminated soil and the bamboo willows are harvested only once.
[0035] The effects of the above embodiments and comparative examples were verified by the following experiments.
[0036] The harvested herbs were dried, crushed, burned, weighed, and digested. The uranium content in the digestion solution was determined by inductively coupled plasma mass spectrometry, and the uranium enrichment in the hyperaccumulator plants was further calculated. The results are shown in Table 1.
[0037] Table 1 Total uranium enrichment of various plants in the restoration cycle of the examples and comparative examples
[0038] As shown in Table 1, compared with Comparative Example 1, Example 1 increases the uranium enrichment in the contaminated soil by 922.98%. Compared with Comparative Example 2, Example 2 increases the uranium enrichment in the contaminated soil by 843.58%. Compared with Comparative Example 3, Example 3 increases the uranium enrichment in the contaminated soil by 138.45%. Compared with Comparative Example 4, Example 4 increases the uranium enrichment in the contaminated soil by 618.44%. Compared with Comparative Example 5, Example 5 increases the uranium enrichment in the contaminated soil by 100.87%. Compared with Comparative Example 6, Example 6 increases the uranium enrichment in the contaminated soil by 637.57%.
[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.
Claims
1. A method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, characterized in that: The steps include: S1. Select seeds or seedlings of uranium hyperaccumulating plants for germination and cultivation. Soak the seeds of uranium hyperaccumulating plants in warm water at 60°C for 2-3 hours, dry naturally, sow them in the soil, germinate naturally, and plant cuttings of uranium hyperaccumulating plant seedlings in the soil, and water them regularly. S2. Transplantation: After the uranium hyperaccumulator plants have grown for a period of time, their seedlings are transplanted into uranium-contaminated soil and watered regularly; S3. Harvesting of uranium hyperaccumulating plants: When the uranium hyperaccumulating plants grow naturally or add chelating agents to enhance the rhizosphere release behavior, harvest the above-ground and underground parts of the plants and measure the uranium enrichment; S4. Repeated planting and harvesting of uranium hyper-enriched plants: After the above-ground and underground parts of the uranium hyper-enriched plants are harvested for the first time, the new uranium hyper-enriched plant seedlings obtained in step S2 are transplanted into uranium-contaminated soil. When the rhizosphere release behavior occurs naturally or after the addition of chelating agents, the above-ground and underground parts of the uranium hyper-enriched plants are harvested to determine the uranium enrichment amount.
2. A method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior according to claim 1, characterized in that: The uranium hyper-enriched plants include one or more of Macleaya oleifera, Commelina vulgaris and Salix babylonica.
3. The method of claim 1 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, characterized in that: In step S1, the specific method of sowing is: sowing 300-500 seeds or 2000-4000 seeds per square meter, and the sowing thickness is 5-10 cm; the specific method of the seedling branch cuttings is: cut a section of the seedling branch with 8 leaves, 18 cm long, retain two leaves on each of the upper 4 leaves, and cut the lower 4 leaves from the petiole, insert the cut seedling branch into the soil 8 cm, and retain 10 cm of branches with leaves outside.
4. The method of claim 1 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, characterized in that: In step S2, 28 to 60 days after the uranium hyperaccumulating plant seeds germinate and grow the first leaf, or 20 days after the uranium hyperaccumulating plant seedlings and branches grow new leaves, the seedlings are transplanted into uranium contaminated soil.
5. The method of claim 1 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, characterized in that: In step S3, the chelating agent includes one or both of oxalic acid and iron carrier.
6. The method of claim 1 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, characterized in that: In step S3, under natural growth conditions, uranium hyperaccumulator plant seedlings are transplanted into uranium-contaminated soil 14-63 days later, when uranium rhizosphere release occurs, the above-ground and underground parts of the plants are harvested and the uranium enrichment is measured.
7. A method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior according to claim 1 or 5, characterized in that: In step S3, when a chelating agent is added, oxalic acid is added to the rhizosphere soil of the uranium hyperaccumulating plants 6-12 days after the uranium hyperaccumulating plant seedlings are transplanted into the uranium contaminated soil. On the 9th to 15th day, iron carriers are added to the rhizosphere soil of the uranium hyperaccumulating plants. After the 12th to 18th day, the uranium hyperaccumulating plant seedlings show uranium rhizosphere release behavior, and the above-ground and underground parts of the plants are harvested to measure the uranium enrichment.
8. The method of claim 1 for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior, characterized in that: In step S4, under natural growth conditions, after the above-ground and underground parts of the uranium hyper-enriched plants are harvested for the first time, the new uranium hyper-enriched plant seedlings obtained in step S2 are transplanted into uranium-contaminated soil and harvested again after 14-63 days. Transplantation and harvesting are performed every 14-63 days, and this cycle is repeated to determine the uranium enrichment amount.
9. A method for improving the efficiency of phytoremediation of uranium-contaminated soil by utilizing plant rhizosphere release behavior according to claim 1 or 5, characterized in that: In step S4, when a chelating agent is added, after the above-ground and underground parts of the uranium hyperaccumulating plant are harvested for the first time, the new uranium hyperaccumulating plant seedlings obtained in step S2 are transplanted into the uranium contaminated soil. 6-12 days after the uranium hyperaccumulating plant seedlings are transplanted into the uranium contaminated soil, oxalic acid is added to the rhizosphere soil of the uranium hyperaccumulating plant. On the 9th to 15th day, iron carriers are added to the rhizosphere soil of the uranium hyperaccumulating plant. After the 12th to 18th day, uranium rhizosphere release behavior occurs, and the above-ground and underground parts of the plant are harvested. This cycle is repeated to determine the uranium enrichment amount.