Brassica campestris growth promoter under selenium-rich and high-cadmium soil conditions

Abstract

The invention belongs to the technical field of selenium enrichment of pakchoi, and particularly relates to a pakchoi growth promoter under selenium-rich and high-cadmium soil conditions. The invention relates to a pakchoi growth promoter under selenium-rich and high-cadmium soil conditions. The pakchoi growth promoter is prepared by uniformly mixing a 1 mmol / L jasmonic acid solution and a 1 mmol / L salicylic acid solution in equal volume and then adding water to dilute for 20 times. The jasmonic acid and the salicylic acid existing in all higher plants are used as raw materials, the optimal formula concentration of the jasmonic acid and the salicylic acid is determined through tests, the synergistic interaction effect of the two hormones is fully exerted, the growth physiological metabolism level of crops in the selenium-rich and high-cadmium soil can be adjusted, the crop yield is increased, and the crop yield is increased. Meanwhile, the content of beneficial element selenium of edible parts of the crops is increased, the content of harmful element cadmium is reduced, healthy and efficient production of the selenium-rich crops is finally achieved, the problems that cadmium exceeds the standard and the yield of the crops is reduced in the utilization process of the selenium-rich and high-cadmium soil are effectively solved, and technical support can be provided for safe utilization of the selenium-rich and high-cadmium soil.

Description

Technical Field

[0001] The invention belongs to the technical field of selenium-enriched pakchoi, and particularly relates to a pakchoi growth promoter under selenium-enriched and high-cadmium soil conditions. Background Art

[0002] Selenium-rich (Se) soil (Se ≥ 0.4 mg / kg) is an important material basis and valuable resource for the development of selenium-rich agriculture. However, Se and cadmium (Cd) are geochemical co-existing elements, so they co-exist in the soil during migration and transformation. Selenium-rich soil is at great risk of cadmium pollution. The selenium-rich areas of Jinhua, Zhejiang, Shitai County, Chizhou, Anhui, the selenium-rich soil areas of Hainan, and the selenium-rich areas of southern Shaanxi have all been found to have cadmium content exceeding the standard to varying degrees. The 1:250,000 surface soil geochemical survey data of Enshi Prefecture, Hubei Province showed that the selenium-rich and high-cadmium soil areas (Se ≥ 0.4 mg / kg; Cd ≥ 0.3 mg / kg) accounted for 45.14% of the area of ​​Enshi Prefecture, covering an area of ​​approximately 10,878.74 km 2 . The cadmium exceeding standard rate in fish ponds in high-selenium areas has reached 100%, and the cadmium exceeding standard multiples are as high as 8 to 800 times. Guangxi's selenium-rich soil also has a high cadmium background value. The cadmium content of a typical selenium-rich and high-cadmium area is 0.30-244.1 mg / kg. Although agricultural products in selenium-rich and high-cadmium soils are rich in selenium, their cadmium content is also generally exceeded, seriously endangering the quality and safety of agricultural products. In addition, cadmium is a heavy metal element that is not essential for plant growth and development. High-cadmium soil is one of the important stress factors that endanger the healthy growth of crops; at the same time, selenium has no special metabolic channels in crops and can only rely on replacing the position of sulfur to bind to proteins. Therefore, increasing the selenium content of crops is likely to cause protein structure and function disorders and produce toxic effects. Selenium-rich and high-cadmium soils have the dual stress factor conditions of high selenium and high cadmium at the same time, which is an important factor leading to crop yield reduction. It can be seen that reducing the cadmium content of crops in selenium-rich and high-cadmium areas and enhancing the growth performance of crops in selenium-rich and high-cadmium soil conditions are important bottlenecks that need to be overcome in order to safely produce selenium-rich crops and improve production efficiency in selenium-rich areas.

[0003] At present, in addition to the relevant mechanisms of plants themselves to cope with Cd and Se stress (antioxidant regulation, hormone regulation, etc.), the technical measures to reduce the Cd content and Cd stress damage in crops have become relatively mature and diverse, and can be roughly divided into three aspects: chemical fortification, biological fortification, and agronomic regulation. The technology to reduce the damage of single Se stress is mainly found in agronomic regulation measures of exogenous plant hormones.

[0004] At present, applying exogenous selenium (nanoselenium, organic selenium, inorganic selenium, selenium fertilizer) through leaves or soil is still the most important technical method to improve the production efficiency of selenium-rich crops in the process of utilizing selenium-rich and high-cadmium soils. The application of exogenous selenium has a relatively stable effect on the selenium enrichment of crops, but its effect on cadmium absorption is affected by many factors such as exogenous selenium concentration, type (form), usage method / frequency, crop variety, environmental conditions, etc., and it may even promote the enrichment of cadmium in crops. On the other hand, the use of exogenous selenium still has problems such as seedling burning, residue (41.82%-82.64%), low utilization rate (soil-applied selenium fertilizer utilization rate 5%-30%, soil-applied sodium selenite utilization rate 0.89%-3.25%), environmental pollution and selenium resource shortage, and is not conducive to giving full play to the advantages of selenium-rich soil resources. In addition, methods such as adding conditioners and microbial preparations to the soil to change the activity of selenium and cadmium in the soil also have good effects in some selenium-rich areas, but this method changes the chemical properties of the original soil to a certain extent, is difficult to operate, has high costs, and has the potential to damage the structure of the soil itself. In severe cases, it will also cause the loss of beneficial elements, weakening of soil fertility, and pollution of water bodies. In addition, the method of using traditional breeding methods or transgenic technology to breed selenium-rich, low-cadmium varieties with high tolerance to selenium and cadmium may be more economical in the long run, but the difficulty lies in the lack of research on the genetic mechanism of selenium / cadmium in crops and the breeding of selenium-rich, low-cadmium germplasm. The research cycle is long, the cost is high, and the stability and safety are unknown, making it difficult to promote and apply.

[0005] In order to make better use of selenium-rich soil resources and address the problem of coexistence of selenium and cadmium in soil, it is still necessary to develop simpler, more practical, efficient, and environmentally friendly regulatory methods to achieve selenium-enriched crops and reduce cadmium and promote healthy growth of crops.

[0006] The use of exogenous substances is an efficient, cheap and environmentally friendly means to solve agricultural problems. Plant hormones have an important influence on the absorption and transport of plant ions and are also the main growth regulators for enhancing crop resistance.

[0007] Salicylic acid is a phenolic compound in the process of plant metabolism. It can be used as a signal molecule required for plant stress resistance to activate plant defense protection mechanism. It not only involves resisting external biological stress, but also participates in coping with various abiotic stresses (high temperature, low temperature, salinity, drought, heavy metals, ultraviolet radiation, ozone and other adversities, etc.), playing a key role in plant signal transduction and stress resistance. Exogenous salicylic acid has been widely used to reduce the stress hazards of various heavy metal elements such as Cd, Hg, Ni, Pb and Mn. The prior art patent CN111386987B discloses that applying salicylic acid can increase the selenium content of pakchoi.

[0008] Jasmonic acid is another plant hormone related to plant resistance. It is closely related to the stress resistance response under biological / abiotic stress such as pests and diseases, salt stress, and drought stress. Jasmonic acid substances in plants can be rapidly upregulated when plants suffer external damage, thereby triggering related signal reactions to resist. In existing technical methods, under a single high-selenium stress condition, exogenous jasmonic acid can effectively improve the tolerance of plants to selenium, thereby promoting the healthy growth of crops and the accumulation of selenium. For example, the patent CN114557244B discloses that exogenous jasmonic acid can increase the selenium content of Chinese cabbage.

[0009] However, there are no reports on the use of a mixture of salicylic acid and jasmonic acid for selenium-enrichment and cadmium-reduction in pakchoi.

[0010] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0011] The purpose of the present invention is to provide a growth promoter for Chinese cabbage under the condition of selenium-rich and high-cadmium soil, which uses jasmonic acid and salicylic acid existing in all higher plants as raw materials, gives full play to the synergistic effect of the two hormones, increases the content of beneficial element selenium in the edible part of crops, reduces the content of harmful element cadmium, and finally realizes the healthy and efficient production of selenium-rich crops.

[0012] To achieve the above object, the present invention provides the following technical solutions:

[0013] A growth promoter for Chinese cabbage under the condition of selenium-rich and high-cadmium soil is prepared by mixing equal volumes of a 1mmol / L jasmonic acid solution and a 1mmol / L salicylic acid solution and then diluting the mixture with water by 20 times.

[0014] Specifically, the preparation method of the jasmonic acid solution is: dissolve 0.2103g of jasmonic acid in a beaker with 10mL of anhydrous ethanol, add 400-600mL of pure water, and add 2mL of Tween-20 (Tween-20), stir and mix, transfer to a 1L volumetric flask, make up to volume, shake well, and obtain a 1mmol / L jasmonic acid solution.

[0015] Specifically, the preparation method of the salicylic acid solution is: dissolve 0.1381g of salicylic acid in 10mL of anhydrous ethanol in a beaker, add 400-600mL of pure water, and add 2mL of Tween-20 (Tween-20), stir and mix, transfer to a 1L volumetric flask, make up to volume, and shake well to obtain a 1mmol / L salicylic acid solution.

[0016] The present invention also provides a method for promoting selenium enrichment and cadmium reduction in Chinese cabbage under selenium-rich and cadmium-rich soil conditions, comprising: when the Chinese cabbage is in the 4-5 leaf stage, the Chinese cabbage growth promoter under the selenium-rich and cadmium-rich soil conditions is evenly sprayed on the front and back sides of the Chinese cabbage leaves until the leaf surfaces are completely wet and water droplets can be seen flowing down the leaf surfaces; spraying is performed continuously for 3 times, with an interval of 5 days between 2 adjacent times.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The invention uses jasmonic acid and salicylic acid existing in all higher plants as raw materials, determines the optimal formula concentration of the two through experiments, gives full play to the synergistic effect of the two hormones, can regulate the growth physiological metabolism level of crops in selenium-rich and high-cadmium soil, improve crop yield, and at the same time increase the content of beneficial element selenium in the edible part of the crops and reduce the content of harmful element cadmium, ultimately achieving healthy and efficient production of selenium-rich crops, effectively coping with the problems of excessive cadmium and crop yield reduction in the process of utilizing selenium-rich and high-cadmium soil, and can provide technical support for the safe utilization of selenium-rich and high-cadmium soil. DETAILED DESCRIPTION

[0019] The following is a clear and complete description of the technical solution of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Example 1

[0021] A growth promoter for Chinese cabbage under selenium-rich and cadmium-rich soil conditions, which is prepared as follows:

[0022] (1) Prepare 1 mmol / L jasmonic acid solution: dissolve 0.2103 g jasmonic acid in 10 mL anhydrous ethanol in a beaker, add 400-600 mL pure water and 2 mL Tween-20, stir and mix, transfer to a 1 L volumetric flask, dilute to volume, and shake to obtain a 1 mmol / L jasmonic acid solution;

[0023] (2) Prepare 1 mmol / L salicylic acid solution: dissolve 0.1381 g salicylic acid in 10 mL of anhydrous ethanol in a beaker, add 400-600 mL of pure water and 2 mL of Tween-20, stir and mix, transfer to a 1 L volumetric flask, make up to volume, and shake to obtain a 1 mmol / L salicylic acid solution;

[0024] (3) Preparation of promoter: Mix equal volumes of 1 mmol / L jasmonic acid solution and 1 mmol / L salicylic acid solution, and dilute by 20 times with water to obtain the promoter for growth of Chinese cabbage under the conditions of selenium-rich and high-cadmium soil.

[0025] Example 2

[0026] A method for promoting selenium enrichment and cadmium reduction of Chinese cabbage under selenium-rich and high-cadmium soil conditions, comprising the following steps:

[0027] When the cabbage is at the 4-5 leaf stage, the cabbage growth promoter under the selenium-rich and cadmium-rich soil conditions of Example 1 is evenly sprayed on the front and back sides of the cabbage leaves until the leaf surface is completely wet and water droplets can be seen flowing down the leaf surface; spraying is performed continuously for 3 times, with an interval of 5 days between each adjacent spraying.

[0028] Example 3

[0029] Select neutral soil (pH = 7.0). Before planting Chinese cabbage, dissolve sodium selenate and cadmium chloride in water and spray them into the soil. After mixing and aging for 6 months, the soil selenium content was measured to be 2.18 mg / kg and the soil cadmium content was 1.58 mg / kg, thus obtaining selenium-rich and high-cadmium soil.

[0030] On October 25, 2023, pakchoi was sown in the prepared selenium-rich and high-cadmium soil. At the 4-5 leaf stage of pakchoi (November 24), the pakchoi growth promoter under the selenium-rich and high-cadmium soil conditions of Example 1 was evenly sprayed on the front and back of the pakchoi leaves until the leaf surface was completely wet and water droplets could be seen flowing down the leaf surface. The spraying was continued for 3 times, with an interval of 5d between the adjacent 2 times. Other daily management was carried out according to the conventional method, and a blank control of spraying an equal amount of clean water was set. At the same time, a single 50 μmol / L salicylic acid and a single 50 μmol / L jasmonic acid were sprayed for comparison. After implementation, samples were collected and tested on December 14, 2023. The effects on pakchoi photosynthetic pigments and fresh weight, selenium and cadmium content of pakchoi are shown in Tables 1 and 2.

[0031] Table 1 Effects of the method of the present invention on photosynthetic pigments of Chinese cabbage grown in selenium-rich and cadmium-rich soil

[0032] Group Chlorophyll a content (mg / g) Chlorophyll b content (mg / g) Total chlorophyll content (mg / g) Carotenoid content (mg / g) Chlorophyll a content / Chlorophyll b content Total chlorophyll content / carotenoid content Blank control 1.620±0.041b 1.083±0.087c 2.703±0.066c 0.162±0.005a 1.503±0.156ab 16.691±0.876b Salicylic acid 1.591±0.201b 1.036±0.190c 2.627±0.113c 0.165±0.005a 1.587±0.441a 15.883±0.649b Jasmonic acid 1.818±0.024b 1.397±0.095b 3.215±0.071b 0.158±0.006ab 1.306±0.104ab 20.343±0.894a Jasmonic acid + salicylic acid 2.089±0.136a 1.958±0.091a 4.047±0.194a 0.151±0.002b 1.068±0.063b 26.747±1.513a

[0033] Note: The values ​​in the table are mean ± standard deviation (n=3). Different lowercase letters indicate significant differences among treatment groups (P<0.05).

[0034] As shown in Table 1, the chlorophyll a content, chlorophyll b content and total chlorophyll content of Chinese cabbage are significantly increased after the method of the present invention is adopted, while there is no significant difference between the spraying of single salicylic acid and the blank control, and the spraying of single jasmonic acid is also significantly increased compared with the blank control, but significantly lower than the method of the present invention. The increase of chlorophyll is crucial for enhancing plant photosynthesis and increasing yield. The test results show that the present invention can significantly improve the photosynthesis potential of Chinese cabbage under selenium-rich and high-cadmium conditions, and its effect is also significantly higher than the single spraying of salicylic acid or jasmonic acid treatment group. In addition, after adopting the method of the present invention, the ratio of total chlorophyll content / carotenoid content is also significantly increased, reflecting that the method of the present invention can increase the ratio of the relative content of chlorophyll in photosynthetic pigments, ensure that there are enough reaction center pigments, and then increase photosynthetic capacity. At the same time, the method of the present invention also reduces the ratio of chlorophyll a content / chlorophyll b content, which helps to improve the efficiency of leaf capture of light energy. Carotenoids are also one of the important pigments involved in photosynthesis, but photochemical reactions will be inhibited only when they are greatly reduced (>40%). Although the method of the present invention reduces the carotenoid content, it does not reach the level of inhibiting photosynthesis as a whole.

[0035] Table 2 Effects of the method of the present invention on the fresh weight and selenium and cadmium contents of Chinese cabbage in selenium-rich and high-cadmium soil

[0036] deal with Fresh weight of aboveground parts (g / plant) Fresh root weight (g / plant) Selenium content in aboveground parts (mg / kg of dry sample) Selenium content in roots (mg / kg in dry sample) Cadmium content in aboveground parts (mg / kg in dry sample) Root cadmium content (dry sample mg / kg) Blank control 5.902±0.964b 0.180±0.034a 5.143±0.604c 2.405±0.781b 7.355±0.266a 9.955±0.684b Salicylic acid 5.818±0.756b 0.164±0.050a 7.190±0.388b 2.050±0.639b 6.913±0.579a 7.750±1.172c Jasmonic acid 6.438±0.819ab 0.201±0.119a 7.665±0.730ab 3.698±0.644a 6.628±0.634a 12.718±1.397a Jasmonic acid + salicylic acid 6.762±0.701a 0.183±0.022a 8.335±0.365a 2.228±1.118b 5.305±0.794b 6.610±1.084c

[0037] Note: The values ​​in the table are mean ± standard deviation. The sample size for fresh weight determination was 9, and the sample size for selenium and cadmium content determination was 4. Different lowercase letters indicate significant differences among treatment groups (P<0.05).

[0038] As shown in Table 2, the method of the present invention significantly increases the aboveground fresh weight of Chinese cabbage, and there is no significant difference in the aboveground fresh weight of salicylic acid or jasmonic acid when spraying a single plant, while the method of the present invention has a significant effect on promoting the growth of Chinese cabbage under selenium-rich and high-selenium stress. In addition, the method of the present invention significantly increases the selenium content of the aboveground part of Chinese cabbage, which is 62% higher than that of the blank control, and the increase is greater than that of the single spraying salicylic acid group and the single spraying jasmonic acid group, effectively promoting the absorption of soil selenium by Chinese cabbage and the transfer to the edible part. As for the harmful element cadmium, the method of the present invention significantly reduces the cadmium content of the aboveground part and the root of Chinese cabbage compared with the control, and reduces the absorption of soil cadmium by Chinese cabbage plants. Although the single spraying of salicylic acid or jasmonic acid has a reducing effect on the aboveground cadmium content, the effect is not significant.

[0039] Overall, it can be seen that the method of the present invention promotes the healthy growth of Chinese cabbage under selenium-rich and high-cadmium soil conditions, increases the selenium content in the edible part, and reduces the cadmium content in the edible part. The effect is also better than spraying single salicylic acid or single jasmonic acid. It can be seen that the present invention is an effective method for simultaneously alleviating the problems of yield reduction and cadmium excess caused by planting crops in selenium-rich and high-cadmium soil, and can provide technical support for the efficient and safe utilization of selenium-rich and high-cadmium soil.

[0040] Example 4

[0041] Alkaline soil (pH = 7.6) was selected. Before planting Chinese cabbage, more sodium selenate and cadmium chloride were dissolved in water and sprayed into the soil. After mixing and aging for 6 months, the soil selenium content was measured to be 2.85 mg / kg and the soil cadmium content was 1.92 mg / kg. Both the soil selenium content and the soil cadmium content were higher than those in Example 3.

[0042] On March 7, 2024, pakchoi was sown in the prepared selenium-rich and high-cadmium soil. At the 4-5 leaf stage of pakchoi (April 5), the pakchoi growth promoter under the selenium-rich and high-cadmium soil conditions of Example 1 was evenly sprayed on the front and back of the pakchoi leaves until the leaf surface was completely wet and water droplets could be seen flowing down the leaf surface. The spraying was continued for 3 times, with an interval of 5d between the adjacent 2 times. Other daily management was carried out according to the conventional method, and a blank control of spraying an equal amount of clean water was set. At the same time, a single 50 μmol / L salicylic acid and a single 50 μmol / L jasmonic acid were sprayed for comparison. After implementation, samples were collected and tested on April 24, 2024. The effects on pakchoi photosynthetic pigments and fresh weight, selenium and cadmium content of pakchoi are shown in Tables 3 and 4.

[0043] Table 3 Effect of the method of the present invention on chlorophyll of Chinese cabbage in selenium-rich and cadmium-rich soil

[0044] Group Chlorophyll a content (mg / g) Chlorophyll b content (mg / g) Total chlorophyll content (mg / g) Carotenoid content (mg / g) Chlorophyll a content / Chlorophyll b content Total chlorophyll content / carotenoid content Blank control 1.570±0.160b 1.404±0.076b 2.974±0.228b 0.152±0.006b 1.117±0.070a 19.581±0.936b Salicylic acid 1.550±0.083b 1.452±0.115b 3.002±0.053b 0.169±0.007a 1.075±0.140a 17.784±0.941b Jasmonic acid 1.662±0.025b 1.541±0.166b 3.203±0.181b 0.171±0.005a 1.086±0.112a 18.705±1.116b Jasmonic acid + salicylic acid 1.967±0.037a 2.120±0.118a 4.087±0.108a 0.150±0.005b 0.930±0.060a 27.316±1.207a

[0045] Note: The values ​​in the table are mean ± standard deviation (n=3). Different lowercase letters indicate significant differences among treatment groups (P<0.05).

[0046] As shown in Table 3, compared with the blank control, the chlorophyll a content, chlorophyll b content and total chlorophyll content of Chinese cabbage were significantly increased after the method of the present invention was adopted; while there was no significant difference between the group treated with single salicylic acid or jasmonic acid and the blank control. Similarly, the increase of chlorophyll is very important for enhancing plant photosynthesis and increasing yield. It can be seen that the method of the present invention can well promote the production of chlorophyll in Chinese cabbage when the concentration of selenium and cadmium in the soil is high.

[0047] In addition, after adopting the method of the invention, the ratio of total chlorophyll content to carotenoid content also increased significantly, which also reflects that the method of the invention can increase the relative content ratio of chlorophyll in photosynthetic pigments, ensure sufficient reaction center pigments, and thus enhance photosynthetic capacity, while spraying single salicylic acid or jasmonic acid does not have such a promoting effect. Carotenoids are also one of the important pigments involved in photosynthesis. In this embodiment, the method of the present invention has no significant effect on the carotenoid content.

[0048] Table 4 Effects of the method of the present invention on the fresh weight and selenium and cadmium contents of Chinese cabbage in selenium-rich and high-cadmium soil

[0049] deal with Fresh weight of aboveground parts (g / plant) Fresh root weight (g / plant) Selenium content in aboveground parts (mg / kg of dry sample) Selenium content in roots (mg / kg in dry sample) Cadmium content in aboveground parts (mg / kg in dry sample) Root cadmium content (dry sample mg / kg) Blank control 5.072±1.357b 0.160±0.036b 6.853±0.336b 4.430±0.580a 8.938±1.166a 8.632±2.105ab Salicylic acid 5.970±1.210ab 0.206±0.054ab 7.260±0.175ab 2.530±0.639b 7.513±0.368ab 8.778±1.326ab Jasmonic acid 6.209±1.673ab 0.210±0.042a 6.865±0.504b 2.795±0.541b 6.560±1.051b 10.730±0.982a Jasmonic acid + salicylic acid 6.827±1.732a 0.217±0.061a 7.515±0.318a 2.455±0.932b 6.390±1.525b 6.468±1.212b

[0050] Note: The values ​​in the table are mean ± standard deviation. The sample size for fresh weight determination was 9, and the sample size for selenium and cadmium content determination was 4. Different lowercase letters indicate significant differences among treatment groups (P<0.05).

[0051] As shown in Table 4, the method of the present invention not only increases the fresh weight of the aboveground part of Chinese cabbage, but also significantly increases the root fresh weight of Chinese cabbage (P<0.05). It can be seen that the method of the present invention has a significant effect on the growth of Chinese cabbage under selenium-rich and high-cadmium soil conditions. Spraying single salicylic acid or jasmonic acid also has a certain effect on improving the fresh weight of the aboveground part, but the effect is not significant (P>0.05). At the same time, the method of the present invention also significantly increases the selenium content in the aboveground part of Chinese cabbage, effectively enhancing the selenium nutritional level of the edible part of Chinese cabbage, while spraying single salicylic acid or jasmonic acid has no significant enhancement effect. For the harmful element cadmium, the method of the present invention significantly reduces the cadmium content in the aboveground part of Chinese cabbage, and spraying single jasmonic acid also has a significant effect on reducing the cadmium content in the aboveground part, while single spraying of salicylic acid has no significant effect on the cadmium content in the aboveground part.

[0052] It can be seen that the method of the present invention promotes the healthy growth of Chinese cabbage under selenium-rich and high-cadmium soil conditions, increases the selenium content in the edible part, reduces the cadmium content in the edible part, and improves the overall production efficiency of selenium-rich crops, which can provide technical support for the efficient and safe utilization of selenium-rich and high-cadmium soils.

[0053] In summary, the present invention utilizes jasmonic acid and salicylic acid as raw materials, gives full play to the synergistic effect of the two hormones, increases the content of the beneficial element selenium in the edible part of crops, reduces the content of the harmful element cadmium, and ultimately achieves healthy and efficient production of selenium-rich crops.

[0054] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A growth promoter for Chinese cabbage under selenium-rich and cadmium-rich soil conditions, characterized in that The preparation method is prepared by mixing equal volumes of 1mmol / L jasmonic acid solution and 1mmol / L salicylic acid solution and then diluting the mixture 20 times with water.

2. The growth promoter for Chinese cabbage under selenium-rich and cadmium-rich soil conditions according to claim 1, characterized in that The preparation method of the jasmonic acid solution is as follows: 0.2103 g of jasmonic acid is dissolved in 10 mL of anhydrous ethanol in a beaker, 400-600 mL of pure water is added, and 2 mL of Tween-20 is added at the same time, and the mixture is stirred and mixed, and the mixture is transferred to a 1 L volumetric flask, fixed to volume, and shaken to obtain a 1 mmol / L jasmonic acid solution.

3. The growth promoter for Chinese cabbage under selenium-rich and cadmium-rich soil conditions according to claim 1, characterized in that The preparation method of the salicylic acid solution is as follows: dissolve 0.1381 g of salicylic acid in 10 mL of anhydrous ethanol in a beaker, add 400-600 mL of pure water, and simultaneously add 2 mL of Tween-20, stir and mix, transfer to a 1 L volumetric flask, make up to volume, and shake well to obtain a 1 mmol / L salicylic acid solution.

4. A method for promoting selenium enrichment and cadmium reduction in Chinese cabbage under selenium-rich and high-cadmium soil conditions, characterized in that: include: When the pakchoi has 4 to 5 leaves, the pakchoi growth promoter under the selenium-rich and cadmium-rich soil conditions of claim 1 is evenly sprayed on the front and back sides of the pakchoi leaves until the leaf surfaces are completely wet and water droplets can be seen flowing down the leaf surfaces; spraying is performed continuously for 3 times, with an interval of 5 days between each adjacent spraying.