New use of nano cerium oxide for promoting seed germination of spinach and seed soaking agent and germination method

Abstract

The application discloses a new use of nano cerium oxide for promoting spinach seed germination, a seed soaking agent and a germination method, and relates to the field of seed soaking agents.The new use is that before germination, the spinach seeds are soaked in the seed soaking agent in the dark and rotated, and the seed soaking agent is a nano cerium oxide solution modified by citric acid.The germination method is that the disinfected spinach seeds are soaked in the nano cerium oxide solution in the dark and rotated.The spinach seed soaking agent is non-toxic and harmless, and after the spinach seed soaking agent is used, the seedling germination rate is high, the seedling root system is developed, the salt stress resistance is strong, and the growth is good.Compared with the method without adding the nano cerium oxide solution, the method makes the bud length of the normally growing spinach increase by more than 73%, and the bud length under the stress of 200 mM NaCl salt increases by more than 256%.

Description

Technical Field

[0001] This invention belongs to the field of agricultural production technology, specifically relating to a new use of nano-cerium oxide to promote the germination of spinach seeds, as well as a seed soaking agent and germination method. Background Technology

[0002] Spinach is a nutritious and economically valuable crop with a long history of cultivation in my country. It is widely grown in many regions and is one of the world's important economic vegetable crops. Soil salinization is a major factor affecting global food production and severely restricts agricultural output. We should shift our breeding philosophy from cultivating crops adapted to saline-alkali land to selecting and breeding salt-tolerant plants adapted to saline-alkali soils.

[0003] Seed germination is a crucial period in the plant growth cycle and is highly sensitive to abiotic environmental factors. The rapid and robust growth of seedlings is closely related to seed germination ability. Nanoparticle seed soaking agents play an important role in the seed germination stage, and their physicochemical properties are key factors influencing their positive or negative impact on seed germination.

[0004] Therefore, using nano-soaking agents to improve the salt resistance of spinach and to explore the salt tolerance mechanism are of great significance.

[0005] Cerium oxide nanoparticles, as a class of metal-based nanomaterials with excellent reactive oxygen species scavenging properties, have been widely used in crop stress research. In recent years, cerium oxide has been shown to promote crop growth, improve plant photosynthesis, and enhance plant resistance. Citric acid (CA) has become a commonly used coating agent due to its stability and availability. However, coating molecules alter the surface chemistry and interactions between nanoparticles and the environment. Coating the surface of nanoparticles also has different effects on the physiological and biochemical processes of plants. Studies have shown that citric acid-coated cerium oxide nanoparticles can effectively increase stem length in tomatoes, increase CAT activity and chlorophyll content in leaves, but do not affect the homeostasis of nutrients in tomato tissues. However, few studies have disclosed whether citric acid-modified cerium oxide nanoparticles can stably and efficiently promote spinach seed germination under salt stress conditions. Summary of the Invention

[0006] In view of the problems existing in the above-mentioned background technology, the purpose of this invention is to provide a new use of nano-cerium oxide to promote the germination of spinach seeds, as well as a seed soaking agent and germination method.

[0007] Specifically, this can be achieved through the following technical solutions:

[0008] A novel application of nano-cerium oxide to promote spinach seed germination: Before germination, spinach seeds are soaked in a light-protected, rotating solution of nano-cerium oxide modified with citric acid.

[0009] Furthermore, the mass ratio of cerium oxide to citric acid in the nano-cerium oxide solution is 1:3.35.

[0010] Furthermore, the concentration of the nano-cerium oxide solution is 50-500 mg / L.

[0011] Furthermore, the particle size of the nano-cerium oxide is 197.5-270.5 nm.

[0012] A seed soaking agent for promoting spinach seed germination, comprising a citric acid-modified nano-cerium oxide solution, and its specific preparation method is as follows:

[0013] 1) Add CeO2 NPs to 100 mL of ethanol aqueous solution to prepare a 0.1 mol / L nano cerium oxide solution, and sonicate in a water bath at 20 °C for 60 min;

[0014] 2) Add citric acid to 100 mL of ethanol aqueous solution to prepare a 0.3 mol / L citric acid solution, and then adjust the pH of the solution to 7-8 with 3 mol / L NaOH.

[0015] 3) Mix the solutions obtained in steps 1) and 2) and stir magnetically for 3 hours. After the ethanol evaporates, centrifuge at 4000 r / min for 15 min, wash and dry in an oven at 70℃ for 24 h to obtain citric acid modified nano-cerium oxide.

[0016] Furthermore, the mass ratio of cerium oxide to citric acid is 1:3.35.

[0017] Furthermore, the volume ratio of water to ethanol in the ethanol-water solution is 4:1.

[0018] A method for promoting spinach seed germination using citric acid-modified cerium oxide nanoparticles involves the following pre-sowing treatment:

[0019] 1) Disinfect spinach seeds in a 1% sodium hypochlorite solution for 15 minutes, then rinse them three times with deionized water to obtain disinfected spinach seeds;

[0020] 2) Prepare a cerium oxide nanoparticle solution with a concentration of 50-500 mg / L by citric acid-modified cerium oxide nanoparticles;

[0021] 3) Place the disinfected spinach seeds from step 1) into a 50mL PE centrifuge tube and add 45mL of nano cerium oxide solution. Soak in the tube in the dark for 24 hours by rotating.

[0022] 4) Wipe the soaked spinach seeds dry and arrange them evenly in a petri dish. Add 5 mL of ultrapure water to the petri dish and incubate at 25°C in the dark for 7 days.

[0023] The present invention has the following beneficial effects:

[0024] 1) This invention uses a solution of citric acid-modified cerium oxide nanoparticles as a seed soaking agent, applied to the germination stage of spinach seeds, which can significantly improve the germination rate and increase the sprout length of the germinating seeds, thus helping to ensure the vigorous growth of the crop in the future.

[0025] 2) The present invention applies citric acid-modified cerium oxide during the germination stage of spinach seeds, which can regulate the malondialdehyde content of spinach seeds, enhance crop resistance, and improve the germination rate of crop seeds.

[0026] 3) After culturing spinach seeds for 7 days using the method of this invention, the normal germination rate reaches over 98%, slightly higher than that of the method using cerium oxide solution without citric acid modification. Under salt stress, the germination rate reaches over 55%, higher than the 45% under cerium oxide solution without citric acid modification. The method of this invention increases the sprout length of normally growing spinach seeds by over 73%, increases the sprout length under salt stress by over 256%, and reduces malondialdehyde content by over 62.9%. Attached Figure Description

[0027] Figure 1 SEM images of the nano-cerium oxide used in the examples and comparative examples;

[0028] Figure 2 The germination rate of spinach exposed to nano-cerium oxide in Examples 1-2 and Control Examples 1-2;

[0029] Figure 3 The spinach shoots exposed to nano-cerium oxide in Examples 1-2 and Control Examples 1-2 are shown to be longer.

[0030] Figure 4 The malondialdehyde content in spinach seeds exposed to nano-cerium oxide in Examples 1-2 and Control Examples 1-2;

[0031] Figure 5 The germination of spinach seeds exposed to nano-cerium oxide in Examples 1-2 and Control Examples 1-2 are shown. Detailed Implementation

[0032] The present invention will be further described below with reference to specific embodiments in order to better understand the technical solution.

[0033] SEM image of the nano-cerium oxide used in this invention is shown below. Figure 1As shown, the specific preparation method of the citric acid-modified cerium oxide nanoparticle solution in this invention is as follows: 1.72 g of CeO2 NPs were added to 100 mL of a water:ethanol solution (8:2 v / v) to reach a concentration of 0.1 mol / L. The solution was sonicated in a water bath at 20°C for 60 min. Separately, 5.76 g of citric acid was added to 100 mL of a water:ethanol solution to reach a concentration of 0.3 mol / L, and the pH of the solution was adjusted to 7–8 with 3 mol / L NaOH. The two solutions were mixed and magnetically stirred for 3 hours. Finally, the ethanol was evaporated, and the solution was centrifuged at 4000 r / min for 15 min, washed, and dried in an oven (70°C) for 24 h to obtain CA-CeO2 NPs.

[0034] Test method:

[0035] 1. Germination rate

[0036] Germination rate = (total number of germinated seeds on day 7 / total number of seeds tested) × 100%. During the test, the seedling roots or cotyledons emerging from the seed coat are considered to be germinating. Only when the seedling roots exceed 1 mm is the root length recorded.

[0037] 2. Bud length

[0038] During the experimental testing, spinach seeds in each petri dish were photographed, and their sprout length was measured using ImageJ.

[0039] 3. Malondialdehyde content

[0040] After the germination test, spinach seedlings were collected and the malondialdehyde content of the spinach seedlings was measured.

[0041] Example 1: Nano-seed impregnation (CA-CO2 group)

[0042] A method for promoting spinach seed germination using nano-cerium oxide includes the following steps:

[0043] 1) Disinfect spinach seeds from Huihe Seed Industry in 1% sodium hypochlorite solution for 15 minutes, then rinse with deionized water 3 times to obtain disinfected spinach seeds;

[0044] 2) Prepare a cerium oxide nanoparticle solution with a concentration of 50 mg / L by citric acid-modified cerium oxide nanoparticles;

[0045] 3) Place the sterilized spinach seeds obtained in step 1) into a 50mL PE centrifuge tube, add 45mL of nano cerium oxide solution, and soak in the tube in the dark for 24 hours by rotating.

[0046] 4) Wipe the seeds from step 3) dry and arrange them evenly in a 63.6 square centimeter petri dish. Add 5 mL of ultrapure water to the petri dish and incubate at 25°C in the dark for 7 days.

[0047] Example 2: Nano-seed impregnation (CA-CO2 + Salt group)

[0048] 1) Disinfect spinach seeds from Huihe Seed Industry in 1% sodium hypochlorite solution for 15 minutes, then rinse with deionized water 3 times to obtain disinfected spinach seeds;

[0049] 2) Prepare a cerium oxide nanoparticle solution with a concentration of 50 mg / L by citric acid-modified cerium oxide nanoparticles;

[0050] 3) Place the sterilized spinach seeds obtained in step 1) into a 50mL PE centrifuge tube, add 45mL of nano cerium oxide solution, and soak in the tube in the dark for 24 hours by rotating.

[0051] 4) Wipe the seeds from step 3) dry and arrange them evenly in a 63.6 square centimeter petri dish. Add 5 mL of NaCl solution and incubate at 25°C in the dark for 7 days.

[0052] Comparison Example 1: Ultrapure Water (CK Group)

[0053] 1) Disinfect spinach seeds from Huihe Seed Industry in 1% sodium hypochlorite solution for 15 minutes, then rinse with deionized water 3 times to obtain disinfected spinach seeds;

[0054] 2) Place the sterilized spinach seeds obtained in step 1) into a 50mL PE centrifuge tube, add 45mL of ultrapure water, and soak in the tube in the dark for 24 hours by rotating.

[0055] 3) Wipe the seeds from step 2) dry and arrange them evenly in a 63.6 square centimeter petri dish. Add 5 mL of ultrapure water and incubate at 25°C in the dark for 7 days.

[0056] Control Example 2: NaCl solution (salt stress group)

[0057] 1) Disinfect spinach seeds from Huihe Seed Industry in 1% sodium hypochlorite solution for 15 minutes, then rinse with deionized water 3 times to obtain disinfected spinach seeds;

[0058] 2) Place the sterilized spinach seeds obtained in step 1) into a 50mL PE centrifuge tube, add 45mL of ultrapure water, and soak in the tube in the dark for 24 hours.

[0059] 3) Wipe the seeds from step 2) dry and arrange them evenly in a 63.6 cm² petri dish. Add 5 mL of NaCl solution and incubate at 25°C in the dark for 7 days.

[0060] The germination of spinach seeds exposed to nano-cerium oxide in the above embodiments and comparative examples are as follows: Figure 5As shown, the germination rate of spinach seeds is shown in the figure. Figure 2 As shown in Table 1, using the blank control (CK) as a baseline, the germination rate of spinach seeds soaked in the spinach seed soaking agent of this invention was improved to a certain extent during germination in the dark. Compared with the salt stress control, the germination rate of spinach seeds soaked in the spinach seed soaking agent of this invention was also significantly improved under salt stress conditions. The spinach seed soaking agent of this invention promotes both the germination rate and salt stress resistance of spinach.

[0061] Table 1 Spinach germination rate

[0062] CK 100 93 93 100 Salt 100 45 45 48.4 <![CDATA[CA-CeO2]]> 100 98 98 105 <![CDATA[CA-CeO2+Salt]]> 100 55 55 59.1

[0063] The effects of the above embodiments and control examples on the germination and sprouting length of spinach seedlings are shown in the figure. Figure 3 As shown in Table 2, using the blank control (CK) as a baseline, the spinach sprout length significantly increased after soaking with the spinach seed soaking agent of this invention during germination in the dark. Compared with the salt stress control, the spinach sprout length also significantly increased under salt stress conditions after soaking with the spinach seed soaking agent of this invention. The spinach seed soaking agent of this invention promotes both the germination and growth of spinach and its ability to grow and develop under salt stress.

[0064] Table 2

[0065]

[0066]

[0067] The malondialdehyde content of spinach seeds exposed to nano-cerium oxide in the above examples and control examples is shown below. Figure 4 As shown, from Figure 4 It can be seen that the method of the present invention reduces the malondialdehyde content of normally grown spinach seeds by more than 62.9%.

Claims

1. The use of nano-cerium oxide to promote spinach seed germination, characterized in that, Before germination, spinach seeds are soaked in a light-protected, rotating solution in a seed soaking agent, which is a citric acid-modified nano-cerium oxide solution. The mass ratio of cerium oxide to citric acid in the nano-cerium oxide solution is 1:3.35, and the concentration of the nano-cerium oxide solution is 50-500 mg / L. The preparation method of the citric acid-modified nano-cerium oxide solution is as follows: 1) Add CeO2 NPs to 100 mL of ethanol aqueous solution to prepare a 0.1 mol / L nano-cerium oxide solution, and sonicate in a water bath at 20 °C for 60 min; 2) Add citric acid to 100 mL of ethanol aqueous solution to prepare a 0.3 mol / L citric acid solution, and then adjust the pH of the solution to 7-8 with 3 mol / L NaOH; 3) Mix the solutions obtained in steps 1) and 2) and stir magnetically for 3 hours. After the ethanol evaporates, centrifuge at 4000 r / min for 15 min, wash and dry in an oven at 70℃ for 24 h to obtain citric acid modified cerium oxide nanoparticles. In steps 1) and 2), the volume ratio of water to ethanol in the aqueous ethanol solution is 4:

1.

2. The use of nano-cerium oxide to promote spinach seed germination as described in claim 1, characterized in that... The particle size of nano-cerium oxide is 197.5-270.5 nm.

3. A method for promoting spinach seed germination using citric acid-modified nano-cerium oxide, characterized in that... The following treatments should be performed before sowing: 1) Disinfect spinach seeds in a 1% sodium hypochlorite solution for 15 minutes, then rinse them three times with deionized water to obtain disinfected spinach seeds; 2) Prepare a cerium oxide nanoparticle solution with a concentration of 50-500 mg / L by citric acid-modified cerium oxide nanoparticles; The preparation method of the citric acid-modified nano-cerium oxide solution is as follows: 2-1) Add CeO2NPs to 100 mL of ethanol aqueous solution to prepare a 0.1 mol / L nano-cerium oxide solution, and sonicate in a water bath at 20 °C for 60 min; 2-2) Add citric acid to 100 mL of ethanol aqueous solution to prepare a 0.3 mol / L citric acid solution, and then adjust the pH of the solution to 7-8 with 3 mol / L NaOH. 2-3) Mix the solutions obtained in steps 2-1) and 2-2) and stir magnetically for 3 hours. After the ethanol evaporates, centrifuge at 4000 r / min for 15 min, wash and dry in an oven at 70℃ for 24 h to obtain citric acid modified cerium oxide nanoparticles. In steps 2-1) and 2-2), the volume ratio of water to ethanol in the aqueous ethanol solution is 4:

1. 3) Place the disinfected spinach seeds from step 1) into a 50mL PE centrifuge tube and add 45mL of nano cerium oxide solution. Soak in the tube in the dark for 24 hours by rotating. 4) Wipe the soaked spinach seeds dry and arrange them evenly in a petri dish. Add 5 mL of ultrapure water to the petri dish and incubate at 25°C in the dark for 7 days.

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