Use and method of polyaspartic acid in improving the cadmium fixation capacity of plant root cell walls and reducing cadmium accumulation in the aboveground part

Abstract

The application discloses application and methods of polyaspartic acid in improving the cadmium fixation capacity of plant root cell walls and reducing cadmium accumulation in the aboveground part, and belongs to the technical field of agricultural environment. The polyaspartic acid can promote the distribution of cadmium in the root cell wall, hinder the transportation of cadmium to the aboveground part through the xylem, thereby reducing the cadmium content of the aboveground part of the plant, relieving the cadmium toxic stress of the aboveground part, and reducing the influence of the edible part of the aboveground crop on human health. In addition, under cadmium stress, the application of the polyaspartic acid can reduce the damage of cadmium to the structure of plant chloroplasts, increase the content of photosynthetic pigments, and promote the accumulation of plant biomass. Therefore, the application of the polyaspartic acid in improving the cadmium fixation capacity of plant root cell walls and reducing cadmium accumulation in the aboveground part has a positive significance for guaranteeing food safety.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of agricultural environment, and particularly relates to application and method of polyaspartic acid in improving cadmium fixation capacity of plant root cell wall and reducing cadmium accumulation in aboveground part. BACKGROUND

[0002] Since the 20th century, the problem of cadmium pollution in farmland soil has become more and more common worldwide. According to incomplete statistics, the area of cadmium pollution in China has reached 2.0x10 4 hm 2 , and the annual output of cadmium-exceeding agricultural products has reached 14.6 billion kilograms. Moreover, the area of cadmium pollution and the annual output of cadmium-exceeding agricultural products are showing a trend of increasing year by year. Cadmium is a major pollutant affecting the environmental quality of agricultural land soil, and has strong biological migration, which can cause harm to human health through the enrichment of food chain. How to ensure the safe use of medium and light cadmium-contaminated farmland soil and effectively prevent cadmium from entering the food chain has become a research hotspot in the field of soil quality and food safety.

[0003] Brassica napus is an important oil crop in China, and has the functions of vegetables, feed and green manure. Ensuring high yield and quality of rapeseed is a major strategic issue related to the national economy and people's livelihood. However, the problem of cadmium pollution in the soil of the main rapeseed production areas seriously limits the increase of yield and quality of rapeseed, and the enrichment of cadmium in edible parts threatens human health. Therefore, reducing the absorption of cadmium by rapeseed and enhancing the retention of cadmium in the root system, and reducing the transportation of cadmium to the edible parts of the aboveground part, are of great significance for improving the utilization potential of cadmium-contaminated soil and breeding rapeseed varieties with low cadmium accumulation in edible parts. SUMMARY

[0004] The present application has found that, under cadmium stress, the application of polyaspartic acid can reduce the damage of cadmium to the structure of plant chloroplast, increase the content of photosynthetic pigment, and promote the accumulation of plant biomass. In addition, polyaspartic acid can also promote the distribution of cadmium in the root cell wall, hinder the transportation of cadmium through the xylem to the aboveground part, thereby reducing the cadmium content in the aboveground part of the plant, alleviating the cadmium toxicity stress of the aboveground part, and promoting the accumulation of biomass.

[0005] Based on this, the present application proposes the following technical solutions:

[0006] Application of polyaspartic acid in improving the cadmium fixation capacity of plant root cell wall.

[0007] Application of polyaspartic acid in preventing the transportation of cadmium from the root to the aboveground part through the xylem of the plant.

[0008] Application of polyaspartic acid in reducing the cadmium content in the aboveground part of the plant.

[0009] Application of polyaspartic acid in reducing the damage of cadmium to the structure of plant chloroplast.

[0010] Application of polyaspartic acid in improving plant biomass accumulation.

[0011] A method for improving the cadmium fixation capacity of plant root cell walls and reducing the cadmium content in the aboveground parts of plants, comprising the following steps:

[0012] Dissolving polyaspartic acid in water to obtain a polyaspartic acid solution; pouring the polyaspartic acid solution onto plant roots to enhance the cadmium fixation capacity of the plant root cell walls and reduce the cadmium content in the aboveground parts of the plants.

[0013] In the above method, the mass concentration of the polyaspartic acid solution is selected from 0.5 to 3.5%, preferably 2%.

[0014] In the above method, the application amount of the polyaspartic acid solution is selected from 15L / mu to 90L / mu, preferably 53L / mu. When applied, it can be dissolved and mixed with water-soluble fertilizer and applied to the plant root zone by drip irrigation.

[0015] In the present invention, the plants include but are not limited to Pennisetum, Sedum alfredii, tomato, corn, sorghum, wheat, rapeseed and sunflower, etc., preferably rapeseed.

[0016] The beneficial effects of the present invention are:

[0017] The application of polyaspartic acid can reduce cadmium damage to plant chloroplast structure, increase photosynthetic pigment content, and promote plant biomass accumulation. Furthermore, polyaspartic acid can promote the distribution of cadmium in root cell walls, hindering the transport of cadmium through the xylem to the aboveground parts of plants, thereby reducing cadmium content in the aboveground parts of plants, alleviating cadmium toxicity stress in the aboveground parts, and promoting the accumulation of leaf biomass. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Effects of PASP on dry matter accumulation of rapeseed under cadmium stress;

[0019] Figure 2 Effects of PASP on the photosynthetic pigment content (right) and cell ultrastructure (left) of rapeseed leaves under cadmium stress;

[0020] Figure 3 The effect of PASP on the resistance index of rapeseed leaves under cadmium stress;

[0021] Figure 4 Effects of PASP on cadmium content and cadmium distribution ratio in roots and leaves of rapeseed under cadmium stress;

[0022] Figure 5 To investigate the effects of PASP on cadmium distribution in root cell walls and cadmium concentration in xylem sap under cadmium stress. DETAILED DESCRIPTION

[0023] The other materials used in the present invention, unless otherwise stated, can be obtained through commercial channels. Unless otherwise specified, other terms used in the present invention generally have the meanings commonly understood by those of ordinary skill in the art. The present invention will be further described in detail below with reference to specific examples and data. The following examples are merely for illustration of the present invention and are not intended to limit the scope of the present invention in any way.

[0024] Example 1

[0025] Cadmium fixation test on rapeseed root cell walls:

[0026] A soil pot experiment was set up. The cadmium-contaminated soil (total cadmium content of 1.24 mg / kg) was collected from a village in Pingdu, Qingdao, Shandong. The soil was dried and sieved, mixed with base fertilizer, and placed in culture pots, with 2.0 kg of soil per pot. Before transplanting rapeseed, base fertilizer was applied: 0.5g / kg of urea, 0.83g / kg of calcium magnesium phosphate, 0.25g / kg of potassium chloride, and 0.09g / kg of boric acid. That is, 1.0g of urea, 1.66g of calcium magnesium phosphate, 0.5g of potassium chloride, and 0.18g of boric acid were applied to each pot of rapeseed. Healthy and plump "Zhongshuang 11" rapeseed seeds were selected for germination, cultured in nutrient solution for two weeks, and healthy seedlings with consistent growth were selected for transplanting into culture pots.

[0027] The experiment involved two treatments: a control (CK) and a PASP treatment (PASP), each replicated six times in randomized blocks to ensure randomization. The PASP treatment included 0.3% PASP in the soil, i.e., 6.0 g of PASP per pot. This 6.0 g of PASP was dissolved in 300 mL of distilled water and poured into the culture pots. The CK treatment was watered with the same amount of distilled water.

[0028] During the incubation period, each pot was watered with 300 mL of distilled water every three days, and pest and disease control measures were taken. Samples were collected after significant growth differences appeared. Leaf ultrastructure was observed using transmission electron microscopy, and leaf photosynthetic pigments, malondialdehyde, hydrogen peroxide, and superoxide anion content, antioxidant enzyme activity, and cadmium content in root and leaf, root cell wall, and xylem bleeding sap were measured. Leaves and roots were oven-dried to constant weight, and the dry matter weight was recorded.

[0029] The test results are as follows Figures 1-5 As shown:

[0030] like Figure 1 As shown in the data, the dry weight of rapeseed leaves in CK and PASP treatments were 0.87 g / plant and 1.12 g / plant, respectively. The application of PASP in mildly cadmium-contaminated soil significantly promoted the dry matter accumulation of rapeseed leaves, which indicated that PASP could promote the growth and yield of rapeseed leaves.

[0031] like Figure 2As shown in the results, the cell ultrastructure was observed by transmission electron microscopy, and it was found that compared with CK, the chloroplasts in the rapeseed leaves treated with PASP were full and more numerous, indicating that PASP alleviated the damage of cadmium to the chloroplast structure of rapeseed, which effectively promoted the synthesis of photosynthetic pigments, thereby increasing the content of photosynthetic pigments, especially chlorophyll a and chlorophyll b, which increased by 22.71% and 19.43% respectively, which can significantly promote the progress of photosynthesis and the accumulation of photosynthetic products.

[0032] like Figure 3 As shown in the results, PASP reduced the malondialdehyde content and hydrogen peroxide accumulation in leaves by 9.35% and 20.63% respectively compared with the control. This may be because PASP activated the antioxidant enzymes CAT and SOD, promoted the removal of reactive oxygen species, thereby alleviating the cadmium toxicity stress in the leaves and promoting the growth of rapeseed leaves.

[0033] The cadmium content and distribution ratio in leaves and roots of different treatments were as follows. Figure 4 As shown, the cadmium content and distribution ratio in leaves of CK and PASP treatments were 4.51 μg / g and 22.80%, and 1.84 μg / g and 5.36%, respectively. The cadmium content and distribution ratio in roots were 13.60 μg / g and 77.20%, and 19.98 μg / g and 94.64%, respectively. These results indicate that PASP significantly increased cadmium content and distribution ratio in roots but significantly decreased cadmium content and distribution ratio in leaves. This suggests that PASP application can significantly inhibit the translocation of cadmium to aboveground parts, thereby reducing cadmium content in aboveground parts, alleviating cadmium toxicity stress in aboveground parts, and reducing the impact of edible aboveground parts on human health.

[0034] Figure 5 The results showed that PASP promoted the retention of cadmium in root cell walls. The cadmium accumulation in root cell walls and the cadmium distribution ratio in PASP-treated plants were 2.69 times and 1.32 times that of CK, respectively. The determination of cadmium concentration in xylem sap further verified that PASP could hinder the entry of cadmium into protoplasts, reduce the cadmium concentration in xylem sap (CK: 1.43 μg / mL, PASP: 0.89 μg / mL), and ultimately inhibit the transport of cadmium from roots to the aboveground parts.

[0035] In summary, application of PASP under cadmium stress alleviated cadmium damage to chloroplast structure in rapeseed, increased photosynthetic pigment content, and promoted rapeseed biomass accumulation. By promoting the distribution of cadmium within root cell walls and hindering its transport through the xylem to the shoots, PASP reduced cadmium content in the shoots, alleviated cadmium toxicity in the shoots, and promoted biomass accumulation.

[0036] In the field application, 2% polyaspartic acid solution can be selected, and the application amount is 53.0 L / mu. When applying, it is dissolved and mixed with water-soluble fertilizer, and is applied to the root zone of rape by drip irrigation.

[0037] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any person skilled in the art can modify or change the above disclosed technology content to equivalent embodiments. However, any simple modification, equivalent change and modification of the above embodiments without departing from the technical solution content of the present application, according to the technical essence of the present application, still belongs to the protection scope of the technical solution of the present application.

Claims

1. Application of polyaspartic acid in reducing cadmium content in the aerial parts of rapeseed.

2. A method for improving the cadmium fixation capacity of rapeseed root cell walls and reducing the cadmium content in the aboveground part of rapeseed, characterized in that: The steps include: Dissolve polyaspartic acid in water to obtain a polyaspartic acid solution; pour the polyaspartic acid solution onto the roots of rapeseed to improve the cadmium fixation capacity of the rapeseed root cell walls and reduce the cadmium content in the aboveground part of the rapeseed.

3. The method according to claim 2, characterized in that The mass concentration of the polyaspartic acid solution is selected from 0.5 to 3.5%.

4. The method according to claim 2, characterized in that The application amount of the polyaspartic acid solution is selected from 15L / mu to 90L / mu.

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