Screening device for improving survival rate of seedlings in heavy metal contaminated soil and breeding method thereof

Abstract

This invention relates to the field of soil pollution control and remediation technology, specifically to a screening device and breeding method for improving the survival rate of seedlings in heavy metal contaminated soil. By setting up two concentration gradients of contaminated soil, the seeds are first placed in the upper low-pollution environment to germinate, and then naturally grow into the lower high-pollution soil. After the plant roots have stably taken root in the lower layer, they are transplanted to a highly contaminated site to be remediated. The purpose of this method is to first cultivate seedlings on a small scale to improve the germination rate, and then transplant the plants to the contaminated environment to ensure a high survival rate and uniform coverage, thereby achieving a better phytoremediation effect.

Description

Technical Field

[0001] This invention relates to the field of soil pollution control and remediation technology, specifically to a screening device and breeding method for improving the survival rate of seedlings in heavy metal-contaminated soil. Background Technology

[0002] Phytoremediation technology for heavy metal contaminated soil is based on the tolerance and hyperaccumulation characteristics of plants to heavy metals. Hyperaccumulating plants absorb, transfer, transform, and accumulate heavy metals in the soil, thereby removing them from the soil. Phytoremediation technology therefore has advantages such as being economical and effective, green and ecological, environmentally friendly, having no significant impact on soil quality, and allowing for in-situ remediation of contaminated soil. It has attracted widespread attention and become a hot topic in the field of ecological restoration, with broad application prospects.

[0003] Globally, heavy metal pollution exists to varying degrees in almost every part of the world, severely impacting human production and economic activities. Due to its wide reach, long duration, and bioaccumulation, heavy metal pollution has become a major challenge for environmental remediation. Soil heavy metal pollution, in particular, is closely related to human health. As a basic structural unit of the biosphere, the soil layer stores a large amount of energy substances and minerals. Pollution of the soil layer not only directly affects the soil ecological environment but also disrupts and imbalances the above-ground ecosystem. Currently, phytoremediation is considered the most environmentally friendly method for heavy metal removal, both domestically and internationally. However, poor site conditions at contaminated sites and low phytoremediation germination rates result in less than ideal remediation outcomes.

[0004] The common method for phytoremediation is to directly sow seeds of native pioneer plants or plants tolerant to heavy metals into contaminated sites. However, this method results in a low germination rate in the contaminated environment, specifically uneven germination, which affects the subsequent remediation effect. To address these issues, this invention patent proposes a device based on the concept of segmented remediation through seedling cultivation and transplanting, aiming to improve the survival rate of plants in contaminated sites. Summary of the Invention

[0005] To address the shortcomings of the existing technologies, the present invention aims to provide a screening device and its breeding method for improving the survival rate of seedlings in heavy metal contaminated soil, and a new functional plant conservation device, so as to improve the germination and survival rate of plant remediation seedlings, ensure high coverage of remediation plants, and thus achieve better soil remediation results.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A screening device for improving the survival rate of seedlings in soil contaminated with heavy metals includes a cultivation box, wherein the cultivation box is provided with an upper space and a lower space, and a non-woven fabric is provided between the upper space and the lower space. Both the upper space and the lower space are filled with soil containing heavy metals.

[0008] The amount of heavy metals filling the upper space is Contaminated soil at mg / kg, the lower space filled The contaminated soil concentration is mg / kg, where 'a' represents the average heavy metal concentration of the contaminated site to be remediated, in mg / kg.

[0009] Preferably, the cultivation box is a bamboo cultivation box.

[0010] Preferably, the nonwoven fabric has uniformly opened planting holes with a diameter of 0.5-1cm.

[0011] Preferably, the nonwoven fabric is fixed inside the box.

[0012] Preferably, a lower layer of soil with a higher concentration of heavy metals is first laid in the cultivation box, and then a layer of non-woven fabric is laid on top of the non-woven fabric with a lower concentration of heavy metals.

[0013] Preferably, the top of the cultivation box is open, the lower space is 3-5cm from the bottom bamboo strip, and the soil height in the upper space is 1-3cm.

[0014] This invention also protects a breeding method for a screening device that improves the survival rate of seedlings in heavy metal-contaminated soil, comprising the following steps:

[0015] (1) Set up two concentration gradients of contaminated soil. Fill the upper space of the cultivation box with soil of low contamination concentration and fill the lower space with soil of high contamination concentration. After the soil is filled, let it stand for two weeks. Place the seeds in the upper space and cultivate the seedlings with the low contamination soil first to make the seeds germinate and ensure the germination rate.

[0016] (2) After the seeds germinate, they naturally grow into the lower space, so that the plant roots can be stably rooted in the lower highly polluted soil.

[0017] (3) When the root system is about 4-6cm long, the seedlings are divided and transplanted to the highly polluted site to be remediated.

[0018] Preferably, in step (1), an aqueous solution of CdCl2·2.5H2O is uniformly mixed into the soil to simulate two concentration gradients of Cd-contaminated soil environment.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. The screening device and breeding method for improving the survival rate of seedlings in heavy metal polluted soil of the present invention use bamboo strips as seedling containers for plants, which is safe and environmentally friendly.

[0021] 2. The screening device and breeding method for improving the survival rate of seedlings in heavy metal polluted soil of the present invention uses non-woven fabric, which can separate the two soil substrates to a certain extent and ensure the smooth growth of plant roots. In addition, the non-woven fabric is provided with planting holes, which can reduce the resistance to plant root growth and facilitate the smooth entry of plant roots into the next soil layer for growth.

[0022] 3. The screening device and breeding method of the present invention for improving the survival rate of seedlings in heavy metal contaminated soil raise seedlings by gradually increasing the pollution concentration. Seedlings are first cultivated in low-pollution soil to promote seed germination and ensure the emergence rate. After emergence, the plants are gradually introduced to a higher pollution environment, providing a certain adaptation time for direct planting in high-concentration pollution sites. This improves the emergence and survival rate of plant remediation seedlings, ensures a high coverage rate of remediation plants, and thus achieves better soil remediation results.

[0023] 4. This method can improve the coverage and uniformity of remediation plants on contaminated sites while ensuring the germination and survival rates of the remediation plants, thereby ultimately enhancing the remediation effect. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the plant cultivation device structure for the screening device and breeding method for improving the survival rate of seedlings in heavy metal contaminated soil according to the present invention.

[0025] Figure 2 This invention relates to a screening device and breeding method for improving the survival rate of seedlings in heavy metal contaminated soil. The diagram shows the nonwoven fabric structure of the plant cultivation device. Detailed Implementation

[0026] The following detailed description, in conjunction with embodiments of the present invention, uses preferred embodiments and accompanying drawings.

[0027] Screening devices to improve the survival rate of seedlings in heavy metal contaminated soil, such as... Figure 1 and Figure 2 As shown, the device includes a cultivation box 1 in which seeds are cultivated and grown. The cultivation box 1 has an upper space 3 and a lower space 4. A non-woven fabric 2 is placed between the upper space 3 and the lower space 4. Both the upper space 3 and the lower space 4 are filled with soil containing heavy metal pollution. The upper space 3 is used to fill soil with low concentration of pollution, and the lower space 4 is used to fill soil with high concentration of pollution.

[0028] The amount of heavy metals filled in the upper space 3 is The lower space 4 is filled with contaminated soil containing mg / kg of polluted soil. The contaminated soil concentration is mg / kg, where 'a' represents the average heavy metal concentration of the contaminated site to be remediated, in mg / kg.

[0029] Furthermore, the cultivation box 1 is a bamboo cultivation box, which uses bamboo strips as a seedling container for plants, making it safe and environmentally friendly.

[0030] Furthermore, the nonwoven fabric 2 is uniformly provided with planting holes with a diameter of 0.5-1cm. The planting holes are provided to reduce the resistance to the growth of plant roots, so that the plants can grow smoothly into the lower layer of highly polluted soil.

[0031] Furthermore, the nonwoven fabric 2 can be fixed inside the box.

[0032] Furthermore, a lower layer of soil with a higher concentration of heavy metals is first laid in the cultivation box 1, and then a layer of non-woven fabric 2 is covered. A lower concentration of heavy metals is laid on top of the non-woven fabric 2 (the connection method of the non-woven fabric 2 in the device is not strictly specified, as long as it achieves the effect of separating the upper and lower soil layers).

[0033] Furthermore, the top of the cultivation box 1 is open, the lower space 4 is 3-5cm away from the bottom bamboo strip, and the soil height in the upper space 3 is 1-3cm.

[0034] Example 1

[0035] Breeding methods to improve the survival rate of seedlings in heavy metal-contaminated soil include the following steps:

[0036] (1) Using the screening device provided by the present invention to improve the survival rate of seedlings in heavy metal polluted soil, CdCl2·2.5H2O aqueous solution is uniformly mixed into the soil to simulate two concentration gradients of Cd polluted soil environment. The culture box 1 is filled with polluted soil. The upper space of the culture box 1 is filled with cadmium polluted soil with a concentration of 10mg / kg and the lower space is filled with cadmium polluted soil with a concentration of 30mg / kg. After the soil is filled, it is left to stand for two weeks. According to the size of the seeds, the seeds are sown according to the density and the season. Alfalfa seeds are placed in the upper low-pollution environment. Seedlings are first cultivated in low-pollution soil to make the seeds germinate and ensure the emergence rate.

[0037] (2) After the seedlings emerge, let them grow naturally into the lower layer of highly polluted soil so that the plant roots can be stably rooted in the lower layer of soil. Determine the scale of the seedling cultivation area based on the area of ​​the site to be restored and the planting density of the plants.

[0038] (3) The root growth of seedlings was measured by destructive sampling. The root length was about 4-6 cm. The seedlings were then divided and transplanted to a highly polluted site to be remediated.

[0039] Comparative Example 1

[0040] Alfalfa seeds were placed in the same cultivation apparatus as in Example 1, and the Cd-contaminated soils of two concentration gradients were replaced with cadmium-contaminated soils at a concentration of 30 mg / kg.

[0041] Comparative Example 2

[0042] Alfalfa seeds were placed in the same cultivation apparatus as in Example 1, and Cd-contaminated soil at two concentration gradients was replaced with uncontaminated soil.

[0043] Results and Discussion

[0044] Table 1 Comparison of seed germination rate and survival rate under different pollution levels

[0045]

[0046] A comparative analysis of seed germination rate and survival rate under different pollution levels showed that when seeds were directly planted in unpolluted soil (0 mg / kg), the germination rate was 85.34% and the seedling survival rate was 80.25%. When planted in low-concentration (10 mg / kg) polluted soil, the germination rate was 82.39% and the seedling survival rate was 76.53%. Compared to unpolluted soil, the germination rate decreased by 2.95% and the survival rate decreased by 3.72% under low-concentration pollution conditions. When planted in high-concentration (30 mg / kg) polluted soil, the germination rate was 70.13%. The survival rate of seedlings was 52.16%. In contrast, by using the method of this invention to set up two concentration gradients of polluted soil, seedlings were first cultivated in low-contamination soil to ensure seed germination and maintain a high germination rate at low concentrations. After germination, the seedlings were gradually transitioned to a higher-contamination environment, providing the plants with a certain adaptation time for direct planting in high-contamination soil. Compared with direct planting in high-contamination soil, the seedling survival rate of seedlings using the concentration gradient method, which first cultivates seedlings in low-contamination soil and then allows them to grow naturally in high-contamination soil, was 70.84%, which is 18.68% higher than that of seedlings directly planted in high-contamination soil.

[0047] In summary, by setting up two concentration gradients of contaminated soil, seeds are first cultivated into seedlings in low-contamination soil to ensure germination and a certain germination rate, providing a certain adaptation space for direct planting in high-contamination sites. Then, the plants are allowed to grow naturally in the higher-contamination soil. Once the plant roots have firmly established themselves in the lower layer of highly contaminated soil, they are transplanted to the high-contamination remediation site. This method can ensure the germination and survival rates of remediation plants while achieving higher and more uniform plant coverage in the contaminated site, ultimately improving the remediation effect.

[0048] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A screening device for improving the survival rate of seedlings in heavy metal contaminated soil, characterized in that, The invention includes a cultivation box (1), which has an upper space (3) and a lower space (4). A non-woven fabric (2) is placed between the upper space (3) and the lower space (4). Both the upper space (3) and the lower space (4) are filled with soil containing heavy metal pollution. The amount of heavy metals filled in the upper space (3) is The contaminated soil was filled with mg / kg of polluted soil, and the lower space (4) was filled with... The contaminated soil concentration is mg / kg, where 'a' represents the average heavy metal concentration of the contaminated site to be remediated, in mg / kg.

2. The screening device for improving the survival rate of seedlings in heavy metal contaminated soil according to claim 1, characterized in that, The cultivation box (1) is a bamboo cultivation box.

3. The screening device for improving the survival rate of seedlings in heavy metal contaminated soil according to claim 1, characterized in that, The nonwoven fabric (2) has uniformly opened planting holes with a diameter of 0.5-1cm.

4. The screening device for improving the survival rate of seedlings in heavy metal contaminated soil according to claim 1, characterized in that, The nonwoven fabric (2) is fixed inside the box.

5. The screening device for improving the survival rate of seedlings in heavy metal contaminated soil according to claim 1, characterized in that, First, a layer of soil with a higher concentration of heavy metals is laid in the cultivation box (1), and then a layer of non-woven fabric (2) is covered. A layer of soil with a lower concentration of heavy metals is laid on top of the non-woven fabric (2).

6. The screening device for improving the survival rate of seedlings in heavy metal contaminated soil according to claim 2, characterized in that, The top of the cultivation box (1) is open, the lower space (4) is 3-5cm away from the bottom bamboo strip, and the soil height in the upper space (3) is 1-3cm.

7. A breeding method based on the screening device for improving the survival rate of seedlings in heavy metal contaminated soil according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Set up two concentration gradients of polluted soil. Fill the upper space (3) of the cultivation box (1) with soil of low pollution concentration and fill the lower space (4) with soil of high pollution concentration. After the soil is filled, let it stand for two weeks. Place the seeds in the upper space (3) and first cultivate the seedlings with low pollution soil to make the seeds germinate and ensure the germination rate. (2) After the seedlings emerge, they naturally grow into the lower space (4), so that the plant roots can be stably rooted in the lower highly polluted soil. (3) When the root system is 4-6cm long, the seedlings are divided and transplanted to the highly polluted site to be remediated.

8. The breeding method according to claim 7, characterized in that, In step (1), an aqueous solution of CdCl2·2.5H2O is uniformly mixed into the soil to simulate two concentration gradients of Cd-contaminated soil environment.

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