Foliage regulation and control method for reducing lead content of edible part of oilseed rape in high-lead-pollution soil

Abstract

The invention discloses a leaf surface regulation and control method for reducing the lead content of edible parts of oilseed rape in high-lead-polluted soil, mannitol, calcium nitrate or monopotassium phosphate solution is sprayed on leaf surfaces to regulate and control the distribution and form of lead in plants, transfer of lead to the edible parts is remarkably reduced, the lead content of leaves is reduced by 50% through mannitol treatment, and the content of lead in the edible parts is reduced by 50%. The lead content of the leaves is lower than the national standard through calcium nitrate treatment. The method is easy and convenient to operate, low in cost and suitable for safe production of medium-light lead pollution farmlands.

Description

Technical Field

[0001] The present invention relates to a foliar regulation method for reducing the lead content in the edible parts of rape in highly lead - polluted soil, and belongs to the field of safe utilization of vegetables in heavy - metal - polluted soil. Background Art

[0002] In the current era of continuously accelerating industrialization, various industrial activities are becoming increasingly frequent and expanding in scale. This development trend has brought many environmental problems, among which the problem of soil lead pollution is particularly prominent and has gradually become a key factor seriously threatening the safety of agricultural products. As a highly toxic heavy metal, lead shows extremely strong stability in the soil environment, and its natural degradation process is extremely slow and almost can be regarded as difficult to degrade. This means that once lead enters the soil, it will exist in it for a long time, continuously accumulate and have a continuous and profound impact on the surrounding ecosystem.

[0003] During the growth process of plants, the roots absorb water and nutrients from the soil, and lead also takes this opportunity to enter the plant body along with the absorption process. Due to the certain enrichment characteristics of lead in plants, after being passed through the food chain layer by layer, it will eventually enter the human body and cause great harm to human health. For example, lead can damage the human nervous system, affect the intellectual development of children, and may also have adverse effects on important organs such as the human hematopoietic system, cardiovascular system, and kidneys.

[0004] Facing the increasingly severe problem of soil lead pollution, scientific researchers are actively exploring various solutions. In the existing technology, phytoremediation technology is a relatively common countermeasure. However, most current phytoremediation research mainly focuses on the accumulation of lead in the roots of plants. Although some plants can transfer lead in the soil to the roots, they cannot effectively confine lead in the roots and are difficult to prevent it from further transferring to the edible parts of plants, so the hidden danger of agricultural product safety cannot be fundamentally solved. At the same time, some research attempts to use soil amendments to reduce the absorption of lead by plants. This method can, to a certain extent, reduce the activity of lead and reduce the uptake by plants. However, the use of soil amendments is often accompanied by high costs, which is an excessive economic burden for large - scale soil remediation. More seriously, some soil amendments may introduce other chemical substances during use. If not properly treated, it is very likely to cause secondary pollution to the soil environment and further damage the soil ecological balance.

[0005] In addition, traditional foliar regulators also have obvious deficiencies in lead pollution control. On the one hand, the mechanism of their control of lead in plants has not been clearly and precisely explained, making it difficult to play a precise role in practical applications. On the other hand, lead in the soil exists in various chemical forms, and different forms of lead show significant differences in plant absorption, transportation, and toxicity. However, existing foliar regulators lack specific solutions for different chemical forms of lead and cannot achieve efficient and precise treatment of lead pollution.

[0006] In summary, existing technical means have certain limitations in solving soil lead pollution and reducing the lead content in the edible parts of plants. Based on this situation, the present invention, by carefully screening specific foliar treatment agents such as mannitol, calcium nitrate, potassium dihydrogen phosphate, etc., and deeply combining with the subcellular distribution and chemical form change rules of lead in plants, aims to directionally inhibit the transfer of lead to the edible parts of plants, and is expected to fill the gap in the existing technology in this field and provide a new and effective way to solve the problem of soil lead pollution and ensure the safety of agricultural products. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a foliar regulation method for reducing the lead content in the edible parts of rapeseed in highly lead-polluted soil, and this method has the characteristics of high efficiency and environmental protection.

[0008] The present invention is realized through the following scheme: A foliar regulation method for reducing the lead content in the edible parts of rapeseed in highly lead-polluted soil. During the growth period of rapeseed, a mannitol solution with a concentration of 50 - 150 μmol·L-1, a calcium nitrate solution with a concentration of 100 - 400 mmol·L-1, or a potassium dihydrogen phosphate solution with a concentration of 120 - 480 mmol·L-1 is evenly sprayed on both the front and back of the leaves. The spraying amount is such that liquid droplets evenly adhere to the leaf surface without dripping. It is sprayed once every 5 days, and a total of 3 sprays are made.

[0009] The preferred concentration of the mannitol solution is 50 μmol·L-1.

[0010] The preferred concentration of the calcium nitrate solution is 400 mmol·L-1.

[0011] The preferred concentration of the potassium dihydrogen phosphate solution is 480 mmol·L-1, which is suitable for the directional fixation of lead in the roots.

[0012] The spraying time is in the morning on sunny days, and the environmental temperature is 15 - 25°C.

[0013] The beneficial effects of the present invention are as follows:

[0014] 1. The foliar regulation method of the present invention for reducing the lead content in the edible parts of rape in highly lead - polluted soil reduces the lead content in leaves by 50% through mannitol treatment, and the lead content in leaves is lower than the national standard (GB 2762 - 2022) through calcium nitrate treatment.

[0015] 2. The foliar regulation method of the present invention for reducing the lead content in the edible parts of rape in highly lead - polluted soil uses potassium dihydrogen phosphate, which can directionally regulate the fixation of lead in the roots and reduce the transfer to the above - ground parts.

[0016] 3. The foliar regulation method of the present invention for reducing the lead content in the edible parts of rape in highly lead - polluted soil can be widely applied to the rape planting in lead - polluted farmland, ensuring the safety of agricultural products. At the same time, it provides a reference for the regulation of other heavy - metal - polluted crops, and has significant economic and social benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the influence of different concentrations of mannitol on the lead content in the roots of rape.

[0018] Figure 2 It is a schematic diagram of the influence of different concentrations of mannitol on the lead content in the leaves of rape.

[0019] Figure 3 It is a schematic diagram of the influence of different concentrations of mannitol on the lead content in the stems of rape.

[0020] Figure 4 It is a schematic diagram of the comparison between the lead content in the leaves of rape under calcium nitrate treatment and the national standard.

[0021] Figure 5 It is the effect of potassium dihydrogen phosphate treatment on the enrichment of lead in the roots. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following further describes the present invention in conjunction with Figures 1-3 However, the protection scope of the present invention is not limited to the described content.

[0023] For clarity, not all features of the actual embodiments are described. In the following description, well - known functions and structures are not described in detail because they would obscure the present invention with unnecessary details. It should be considered that in the development of any actual embodiment, numerous implementation details must be made to achieve the specific goals of the developer, such as changing from one embodiment to another according to the relevant system or business limitations. Additionally, it should be considered that such development work may be complex and time - consuming, but it is only routine work for those skilled in the art.

[0024] 1. Selection of foliar treatment agents:

[0025] Mannitol: As an osmotic regulator, it alleviates the cell water imbalance caused by lead stress and interferes with the transmembrane transport of lead. It is preferably 50 μmol·L-1, and the lead content in leaves is reduced by 59%.

[0026] Calcium nitrate: Calcium ions compete for the lead absorption sites and enhance the fixation of lead by the cell wall. It is preferably 400 mmol·L-1, and the lead content in leaves is reduced to 0.25 ± 0.1

[0027] 0.25 ± 0.1 mg·kg-1.

[0028] Potassium dihydrogen phosphate: It forms an insoluble lead phosphate compound with lead, reducing its bioavailability and is applicable to lead fixation in roots. It is preferably 480 mmol·L-1.

[0029] 2. Spraying method:

[0030] Start the treatment when the rape grows to 30 days (two-leaf stage), select a sunny morning for spraying to avoid high-temperature evaporation. Spray until the liquid droplets are evenly attached to both the front and back of the leaves, and spray once every 5 days for a total of 3 times.

[0031] Example 1: Mannitol treatment

[0032] 1. Prepare a 50 μmol·L-1 mannitol solution and fill it into a 100 mL spray bottle.

[0033] 2. Plant rape in lead-contaminated soil (500 mg·kg-1). After 30 days of growth, spray both the front and back of the leaves on a sunny morning (temperature 20 °C) until the liquid droplets are evenly attached.

[0034] 3. Spray once every 5 days for a total of 3 times. After harvesting, it is measured that the lead content in leaves is reduced from 0.39 mg·kg-1 of the control to 0.14 ± 0.01 mg·kg-1, with a reduction of 59%.

[0035] Example 2: Calcium nitrate treatment

[0036] 1. Prepare a 400 mmol·L-1 calcium nitrate solution, and the spraying method is the same as that in Example 1.

[0037] 2. After the treatment, the lead content in rape leaves is 0.25 ± 0.1 mg·kg-1, which is lower than the national standard limit (0.3 mg·kg-1).

[0038] Example 3: Potassium dihydrogen phosphate treatment

[0039] 1. Prepare a 480 mmol·L-1 potassium dihydrogen phosphate solution, and the spraying method is the same as that in Example 1.

[0040] 2. The enrichment amount of lead in roots increases by 28%, and the lead content in stems and leaves has no significant change, which is applicable to the scenario where lead fixation in roots needs to be strengthened.

[0041] Although the technical solutions of the present invention have been described and enumerated in detail, it should be understood that for those skilled in the art, making modifications to the above embodiments or adopting equivalent alternative solutions is obvious to those skilled in the art. These modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection required by the present invention.

Claims

1. A foliar control method for reducing the lead content in the edible part of rapeseed in high-lead contaminated soil, characterized in that: During the rapeseed growth period, spray 50-150 μmol·L-1 mannitol solution, 100-400 mmol·L-1 calcium nitrate solution or 120-480 mmol·L-1 potassium dihydrogen phosphate solution evenly on the front and back of the leaves. The spraying amount should be such that droplets are evenly attached to the leaf surface without dripping. Spray once every 5 days, for a total of 3 times.

2. The foliar regulation method for reducing the lead content in the edible part of rapeseed in high-lead contaminated soil according to claim 1, characterized in that: The preferred concentration of the mannitol solution is 50 μmol·L-1.

3. The foliar regulation method for reducing the lead content in the edible part of rapeseed in high-lead contaminated soil according to claim 1, characterized in that: The preferred concentration of the calcium nitrate solution is 400 mmol·L-1.

4. The foliar regulation method for reducing the lead content in the edible part of rapeseed in high-lead contaminated soil according to claim 1, characterized in that: The preferred concentration of the potassium dihydrogen phosphate solution is 480 mmol·L-1, which is suitable for directional fixation of lead at the root.

5. The foliar regulation method for reducing the lead content in the edible part of rapeseed in high-lead contaminated soil according to claim 1, characterized in that: The spraying time is in the morning on a sunny day with an ambient temperature of 15-25°C.

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