A method of alleviating crop plasticizer stress

Abstract

The application discloses a method for relieving crop plasticizer stress, and belongs to the technical field of safe production of agricultural products. The method comprises the following steps: mixing zeolite molecular sieve in soil for planting crops, and spraying selenium-containing foliar fertilizer to the crops during planting. The application discloses, for the first time, the beneficial effect of the combined action of zeolite molecular sieve and foliar selenium fertilizer in relieving the stress of plasticizer on crops. By mixing zeolite molecular sieve in plasticizer-polluted soil and spraying foliar selenium fertilizer to the crops during growth, the accumulation of plasticizer in the plants can be significantly reduced, and the inhibition of plasticizer on the growth of crops can be improved. By using the method, the plasticizer pollution on crops can be effectively controlled and reduced, and the adverse effects of plasticizer on the quality and safety of agricultural products can be avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of safe production of agricultural products, and particularly relates to a method for relieving crop plasticizer stress by using zeolite molecular sieve and foliar selenium fertilizer. BACKGROUND

[0002] Phthalic acid esters (PAEs) are widely used as plasticizers in plastic and pesticide industries. Because these PAEs compounds do not form a combination with the product molecules, they are easily released from plastics into the environment. With the increasing production and use of PAEs, their concentration in various environmental media such as water, air, soil and sediment has gradually increased, and PAEs have also been detected in plants and human bodies (Wang, 2013).

[0003] PAEs are difficult to degrade and not easy to volatilize, and have become one of the most widely existing environmental pollutants on earth. Therefore, the U.S. Environmental Protection Agency has listed six PAEs, including di(2-ethyl)hexyl phthalate (DEHP), dibutyl phthalate (DBP), butyl benzyl phthalate (BBP), diethyl phthalate (DEP), dimethyl phthalate (DMP) and di-n-octyl phthalate (DOP), as priority controlled pollutants.

[0004] PAEs in soil affect the structure of microbial community structure and other ways, and then affect the structure of soil nitrogen form, and are absorbed into the plant body through the plant root system, and then affect the growth of the plant body through various mechanisms. Plasticizers can also accumulate in vegetables and grain seeds, and then enter the human body through food, which can cause serious harm to human health after long-term and large-scale intake.

[0005] China is the world's largest tobacco producer and consumer. In recent years, with the widespread application of mulching film technology in tobacco cultivation, the residual mulching film in the soil has also increased, resulting in the release of a large amount of PAEs into the soil. Studies have shown that DBP has a strong inhibitory effect on the growth of tobacco. Therefore, we urgently need to develop a preparation that can reduce the absorption and accumulation of plasticizers by crops to cope with plasticizer stress.

[0006] ZSM-5 molecular sieve is a new type of zeolite molecular sieve containing organic amine cations, which has excellent catalytic performance, selective adsorption performance, and also has the advantages of thermal stability and chemical stability, and is widely used in catalytic reactions, adsorbent materials and separation membrane materials (Zhang et al., 2022). However, there are few reports on the use of ZSM-5 molecular sieve in relieving abiotic stress of plants.

[0007] Selenium (Se) is a non-essential element for plants, which can promote plant growth and improve plant tolerance to abiotic stress (Djanaguiraman et al., 2005). However, it is still unclear whether Se can reduce the absorption of plasticizers by plants. SUMMARY

[0008] The present application aims to provide a method for effectively alleviating the stress of plasticizers on crops in a soil environment contaminated by plasticizers, so as to reduce the accumulation of plasticizers in crops and solve the adverse effects of plasticizers in soil on the quality and safety of agricultural products.

[0009] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0010] The present application provides the application of zeolite molecular sieve in alleviating the stress of plasticizers on crops, which comprises mixing zeolite molecular sieve in the soil where crops are planted, and spraying selenium-containing foliar fertilizer to the crops during planting.

[0011] Further, the plasticizer is phthalate, which can be but is not limited to dibutyl phthalate.

[0012] Further, the manifestations of the stress of plasticizers include the accumulation of plasticizers in crops and the inhibition of crop growth. Studies have shown that the growth of crops under the stress of plasticizers can lead to the accumulation of plasticizers in the plant body, seriously affecting the normal growth and development of the plant, and inhibiting the synthesis and accumulation of nutrients in the leaves. Specifically, the biomass and chlorophyll content decrease significantly; the contents of potassium and manganese ions decrease significantly, and the content of iron ions increases significantly; the stomatal conductance and apparent transpiration rate of plant leaves increase significantly.

[0013] The present application has shown that by mixing zeolite molecular sieve in plasticizer-contaminated soil and spraying selenium foliar fertilizer, the accumulation of plasticizers in plants can be significantly reduced, the inhibition of plasticizers on crop growth can be significantly improved, and the influence of plasticizers on the synthesis of chlorophyll and normal photosynthesis of crops can be alleviated.

[0014] Further, the zeolite molecular sieve can be but is not limited to ZSM5.

[0015] Further, 600-1000 mg of ZSM5 is mixed per kilogram of soil.

[0016] Further, the selenium-containing foliar fertilizer can be but is not limited to a sodium selenite solution. The concentration of the sodium selenite solution is 10-20 mg / L, which is prepared by dissolving sodium selenite in water.

[0017] Further, the crop is tobacco. In the present application, the combination of mixing zeolite molecular sieve in the soil and spraying selenium fertilizer on the leaf surface significantly reduces the accumulation of plasticizer in tobacco and other crops under plasticizer stress.

[0018] The present application also provides a method for relieving tobacco plasticizer stress, comprising the following steps:

[0019] (1) mixing ZSM5 in the plasticizer contaminated soil to be planted, and then transplanting five-leaf stage tobacco seedlings;

[0020] (2) After the tobacco seedlings are transplanted, 10-20 mg / L sodium selenite solution is sprayed on the surface of the tobacco leaf surface to make it evenly wet on the 1st day and the 3rd day.

[0021] Further, the ZSM5 is prepared by mixing tetrapropylammonium hydroxide, tetraethyl orthosilicate, sodium aluminate, sodium hydroxide and water according to the molar ratio of TPAOH:SiO2:Al2O3:Na2O:H2O 0.2:1:0.02:0.09:35, and then by hydrothermal synthesis method, specifically, first dissolve tetrapropylammonium hydroxide in water, then add sodium aluminate, tetraethyl orthosilicate and sodium hydroxide, stir and mix uniformly, then add to the reaction kettle, crystallize at 200℃ for 24h, take out the reaction liquid after quenching, collect the solid precipitate, wash with circulating water, then dry, and then calcine at 550℃ for 6h to obtain the ZSM5.

[0022] Further, in step (1), 800mg of ZSM5 is mixed per kilogram of soil.

[0023] Further, in step (2), a sprayer is used to uniformly spray the sodium selenite solution on the surface of the tobacco leaf to make it evenly wet. The spraying time is selected in the morning or evening.

[0024] The present application has the following beneficial effects:

[0025] The present application first discloses the beneficial effects of the combination of zeolite molecular sieve and leaf selenium fertilizer in relieving the stress of plasticizer on crops. By mixing zeolite molecular sieve in the plasticizer contaminated soil, and spraying leaf selenium fertilizer during the growth of crops, the accumulation of plasticizer in plants can be significantly reduced, and the inhibition of plasticizer on crop growth can be improved. The method of the present application can effectively control and reduce the plasticizer pollution of crops, and avoid the adverse effects of plasticizer on the quality and safety of agricultural products. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 XRD spectrum of the ZSM5 sample prepared in Example 1.

[0027] Figure 2 SEM image of the ZSM5 prepared in Example 1.

[0028] Figure 3 Phenotype comparison of the control group (CK), plasticizer treatment group (DBP), and plasticizer + alleviator treatment group (DBP+M, nanomaterial + foliar spraying of selenium).

[0029] Figure 4 Comparison of the fresh weight (a) and dry weight (b) of the above-ground parts of the control group (CK), plasticizer treatment group (DBP), and plasticizer + alleviator group (DBP+M).

[0030] Figure 5 Comparison of the plasticizer content in the above-ground parts of the control group (CK), plasticizer treatment group (DBP), and plasticizer + alleviator group (DBP+M).

[0031] Figure 6 Comparison of the SPAD value of the control group (CK), plasticizer treatment group (DBP), and plasticizer + alleviator group (DBP+M). DETAILED DESCRIPTION

[0032] The application will be further described below in conjunction with specific examples. The following examples are only used to illustrate the application and are not used to limit the applicable scope of the application. Modifications or replacements of the methods, steps, or conditions of the application, without departing from the spirit and essence of the application, all belong to the scope of the application.

[0033] The test methods used in the following examples are conventional methods unless otherwise specified; the materials, reagents, etc. used are reagents and materials available through commercial channels unless otherwise specified.

[0034] Nutrient soil was purchased from Laifeng Gardening Supplies Shop in Binjiang District, Hangzhou; dibutyl phthalate (DBP), CAS: 84-74-2; sodium selenite, CAS: 10102-18-8.

[0035] Example 1: ZSM5+Se alleviates DBP stress in tobacco

[0036] 1. Synthesis of ZSM-5

[0037] ZSM-5 was synthesized by hydrothermal synthesis method, and the use amount of each raw material was (molar ratio) TPAOH: SiO2: Al2O3: Na2O: H2O = 0.2: 1: 0.02: 0.09: 35.

[0038] The use amount of each raw material was: tetrapropylammonium hydroxide: 16.3 mL; tetraethyl orthosilicate: 23.1 mL; sodium metaaluminate: 0.45 g; sodium hydroxide: 0.54 g; deionized water: 63 g.

[0039] Take 63 g of distilled water into a beaker, take 16.3 mL of tetrapropylammonium hydroxide, slowly add distilled water, use a magnetic heating stirrer to stir at 30°C for 30 min. Then add 0.45 g of sodium metaaluminate, 23.1 mL of tetraethyl orthosilicate and 0.54 g of sodium hydroxide in turn, continue to stir for 3 h. Put the solvent into the reaction kettle, use an electric heating drying oven to crystallize at 200°C for 24 h, take out the reaction kettle, quench to the temperature at which the reaction kettle can be opened naturally, pour the solution into a beaker, wait for the solid to precipitate in the solution, pour away the upper part of the water, add new distilled water, and wash with water for one day. Then pour away the distilled water in the beaker, leave the generated solid product, use an electric heating drying oven to bake at 120°C for 12 h. Finally, the dried solid product is calcined, using a box-type resistance furnace at 550°C for 6 h, to prepare ZSM-5.

[0040] ZSM5 phase and texture characterization identification: X-ray powder diffraction (XRD) analysis was performed on a D / max-2500 type X-ray diffractometer. The results show that the characteristic peaks belonging to ZSM-5 molecular sieve appear at 2θ = 7.83° and 8.66°, as shown in Figure 1 . The structure of ZSM5 was further verified by SEM technology, as shown in Figure 2 .

[0041] 2, DBP treatment

[0042] The tobacco variety used in this example is K326. After sterilization of the tobacco seeds, germination is carried out in the dark, and after germination, the seeds are moved to a vermiculite culture medium. The tobacco seedlings are cultured in a constant temperature and light incubator, and the culture temperature is 22°C / 18°C. At the five-leaf stage, healthy and uniform tobacco seedlings are selected and moved to the nutrient soil for treatment. Three treatments are set up, which are (1) control (CK); (2) DBP: concentration is 50 mg / kg, method is: dissolve DBP in acetone, prepare 1000 mg / L DBP mother liquor, calculate the required amount of DBP according to the weight of the nutrient soil, draw the corresponding volume from the mother liquor, spray on the soil surface, place in a cool place for 3 days to volatilize the acetone, fully stir and then put into the culture pot; (3) DBP+M: 50 mg / kg DBP+800 mg / kg ZSM-5+foliar spraying of 15 mg / L sodium selenite solution, method is: before transplanting tobacco, add 800 mg of ZSM5 per kg of nutrient soil containing 50 mg / kg of DBP, stir evenly; after transplanting tobacco, spray 15 mg / L of selenium solution on the tobacco leaf surface evenly with a sprayer at 1 day and 3 days after transplanting, and choose the spraying time at 9 am or 4 pm.

[0043] After 28 days of treatment, the aboveground parts of tobacco plants were sampled for biomass determination (Lin et al., 2022) and DBP content determination; the chlorophyll content of the leaves was determined using a handheld SPAD meter; the transpiration rate and stomatal conductance were determined using a LI-600 fluorescence-stomatal meter (Yang et al., 2024); the ion content of the aboveground parts was determined as follows.

[0044] 2.1 DBP content determination

[0045] (1) Prepare the DBP standard solution: respectively take 1000 μL, 500 μL, 250 μL, 100 μL, 40 μL of the standard stock solution into a 10 mL volumetric flask, then accurately add 50 μL of the internal standard solution, and dilute to volume with isopropyl alcohol. The prepared series of standard working solutions are 100 μg / mL, 50 μg / mL, 25 μg / mL, 10 μg / mL, and 4 μg / mL.

[0046] (2) Sample pretreatment: weigh 0.5 g of the ground sample into a 25 mL stoppered triangular flask, accurately add 2 mL of dichloromethane: acetone (3:1, V / V) and 50 μL of the internal standard solution, and ultrasonically extract for 40 min. Take an appropriate amount of the extract into a centrifugal test tube, add solid dispersant, and centrifuge for 10 min at 4000 r / min. Take the upper clear liquid for GC-MS analysis.

[0047] (3) GC-MS analysis conditions: chromatographic column: flexible capillary chromatographic column; stationary phase: 5% phenyl / 95% methyl polysiloxane; specifications: [30 m (length) x 0.25 mm (inner diameter) x 0.25 μm (film thickness)]; injection port temperature: 280℃; injection volume: 1 μL, split injection (split ratio 30:1); carrier gas: helium (purity ≥ 99.999%), constant flow rate: 1.0 mL / min; temperature program: initial temperature 60℃, hold for 1 min, at a rate of 20℃ / min to 220℃, hold for 1 min, then at a rate of 5℃ / min to 280℃, hold for 15 min; ionization mode: electron impact source (EI); ionization energy: 70 eV; transfer line temperature: 280℃; ion source temperature: 230℃; quadrupole temperature: 150℃; measurement mode: selected ion monitoring mode (SIM) scanning; solvent delay: 6 min.

[0048] (4) DBP content calculation: dilute the mixed standard solution into a series of standard solutions, take the standard concentration x (μg / mL) as the abscissa, and the peak area ratio y of the control and the internal standard as the ordinate, draw the standard curve, and calculate the target content in the sample.

[0049] 2.2 Tobacco aboveground ion content determination

[0050] Weigh 0.3g of the aerial part sample into a digestion tube and label it accordingly. Add 3mL of concentrated nitric acid to the tube and incubate overnight in a fume hood. Place the digestion tube containing the concentrated nitric acid into a digester. First, adjust the temperature to 90-100℃ while gently shaking the tube. When the sample loses its shape and becomes liquid, appropriately raise the temperature to 110-120℃ and heat until the sample is completely dissolved into a liquid. Raise the temperature to 130-140℃ and wrap the sides of the digestion tube with aluminum foil to keep it warm, and drain off excess concentrated nitric acid.

[0051] After the liquid in the digestion tube remains at 1-1.5 mL, cool it and add distilled water to bring the volume to 50 mL, then dilute it 5 times. Send the diluted sample for analysis, and use inductively coupled plasma mass spectrometry (ICP-MS) to determine the content of ionic elements (K, Mn, Fe, Cu, and Zn) in the sample under different treatments.

[0052] 3. Experimental Results

[0053] 3.1 Phenotypic observation and biomass determination

[0054] Depend on Figure 3 It can be clearly seen that the addition of DBP to the soil severely inhibited plant growth, but the inhibitory effect of DBP on plant growth was significantly alleviated after the addition of nanomaterials and foliar spraying of Se. This was manifested in the plants being significantly larger than those in the DBP-treated group and close to the control group, showing a good alleviating effect.

[0055] Compare and analyze the fresh weight of the aboveground parts of the plants under different treatments. Figure 4 -a), dry weight ( Figure 4 -b). In the control group, the fresh weight of the aboveground parts of the plants was 6.56 g and the dry weight was 0.55 g. The application of DBP alone significantly reduced the fresh weight to 3.97 g, a decrease of 39.6% compared to the control, and the dry weight to 0.34 g, a decrease of 38.1%. This indicates that the presence of plasticizers such as DBP severely affects the normal growth and development of the plants, inhibits the synthesis and accumulation of nutrients in the leaves, and will seriously affect tobacco yield. In contrast, the DBP+M treatment significantly increased the fresh weight and dry weight of the aboveground parts by 70.5% and 65.6%, respectively, compared to the DBP treatment. These results demonstrate that the ZSM5+Se combination can significantly alleviate the inhibitory effect of DBP on tobacco growth.

[0056] 3.2 Determination of DBP content

[0057] The DBP content in the aboveground parts of plants under the two treatments, DBP and DBP+M, was compared and analyzed. Figure 5It can be seen that compared with DBP alone treatment, DBP+M treatment of plant aboveground DBP content decreased significantly by 44.8%. It shows that ZSM5+Se combination can significantly reduce the accumulation of DBP in tobacco aboveground.

[0058] 3.3 Chlorophyll content determination

[0059] The chlorophyll content in the leaves of the plants treated with DBP and DBP+M was compared and analyzed, and it was found that Figure 6 It can be seen that compared with the control group, the SPAD value of tobacco leaves treated with DBP decreased significantly by 22.97%, which is consistent with the result of visual comparison of leaf color, indicating that the presence of plasticizers such as DBP in the soil will cause a significant decrease in the chlorophyll content of tobacco plants, seriously affecting their photosynthesis and other normal physiological and biochemical reactions, and ultimately inhibiting the normal growth and development of the plants. However, in the DBP+M treatment, the SPAD value did not differ significantly from the control group, but it was significantly higher than that of the DBP treatment by 26.50%, indicating that the ZSM5+Se combination plays a significant role in alleviating the effects of plasticizers on chlorophyll synthesis and normal photosynthesis and other physiological activities.

[0060] 3.4 Stomatal conductance and apparent transpiration rate determination

[0061] The results of stomatal conductance determination showed that compared with the control, the stomatal conductance of tobacco treated with DBP increased significantly by 185.0%; while the application of ZSM5+Se significantly reduced the increase in stomatal conductance caused by DBP, and compared with DBP treatment, the stomatal conductance of DBP+M decreased significantly by 45.2% (Table 1).

[0062] Compared with the control, the apparent transpiration rate of tobacco treated with DBP increased significantly by 66.0%; after the application of ZSM5+Se, the apparent transpiration rate decreased significantly by 37.9% compared with DBP (Table 1).

[0063] Table 1. Stomatal conductance and apparent transpiration rate of tobacco treated with DMP and M

[0064]

[0065] Note: a, b and c represent significant differences at the 0.05 level.

[0066] 3.5 Determination of ion content in aboveground part

[0067] The results of ion content determination in the aboveground part showed that DBP treatment significantly reduced the content of K and Mn, while increasing the content of Fe. Compared with DBP treatment, the content of K and Mn in DBP+M leaves increased significantly by 12.3% and 64.3%, respectively, while the content of Fe decreased significantly by 62.6% (Table 2).

[0068] Table 2. Ion content in tobacco shoots (mg kg -1 )

[0069]

[0070]

[0071] Note: a and b indicate significant difference at 0.05 level.

[0072] It is to be understood that the application is not limited to the examples described above, which can be modified or adapted by those skilled in the art in the light of the above description, all such modifications and adaptations being intended to fall within the scope of the application as defined in the claims appended hereto.

Claims

1. Use of a zeolitic molecular sieve for alleviating plasticizer stress in crops, characterized in that, The application comprises mixing zeolite molecular sieve into soil for crop planting and spraying selenium-containing foliar fertilizer to crops during planting; The plasticizer is dibutyl phthalate; The zeolite molecular sieve is ZSM5; The selenium-containing foliar fertilizer is sodium selenite solution with a concentration of 10-20 mg / L; The crop is tobacco.

2. Use according to claim 1, wherein The manifestations of plasticizer stress include accumulation of plasticizer in crops and inhibition of crop growth.

3. The use according to claim 1, wherein 600-1000 mg of ZSM5 is mixed per kilogram of soil.

4. A method of alleviating tobacco plasticizer stress, characterized in that, The method comprises the following steps: (1) mixing ZSM5 into plasticizer-contaminated soil to be planted, and then transplanting five-leaf-stage tobacco seedlings; the plasticizer is dibutyl phthalate; (2) after the tobacco seedlings are transplanted, spraying sodium selenite solution with a concentration of 10-20 mg / L on the surface of tobacco leaves to make the leaves wet.

5. The method of mitigating plasticizer stress in tobacco of claim 4, wherein, In step (1), 800 mg of ZSM5 is mixed per kilogram of soil.

6. The method of mitigating plasticizer stress in tobacco of claim 4, wherein, In step (2), the sodium selenite solution is sprayed in the morning or in the evening.

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