Method for improving salt tolerance of castor seeds based on nano-zinc oxide initiation

Abstract

The invention belongs to the technical field of commercial crop cultivation. The method comprises the following steps: S1, weighing nano zinc oxide particles; s2, adding water for preparation, and ultrasonically dispersing the nanoparticles; s3, selecting castor seeds, soaking the castor seeds in the nano-zinc oxide suspension, and performing seed initiation treatment by oscillation and shading; s4, putting the soaked seeds into a nylon mesh bag, and drying at room temperature until the initial water content of the seeds is reached; and S5, sowing the castor seeds subjected to initiation treatment, and carrying out stress treatment with salt of different concentrations. In order to solve the problems that the germination rate of castor-oil plants is low and seedlings are difficult to grow in the northeast saline areas, the method provided by the invention performs initiation treatment on castor-oil plant seeds by using a nano-zinc oxide suspension, so that the salt tolerance of the castor-oil plants under salt stress is remarkably improved, and the germination of the seeds under salt stress and the growth of the germinated seedlings are promoted. The initiator disclosed by the invention is low in price, environment-friendly and pollution-free, the initiation process is simple to operate, and the initiator has important significance on large-scale popularization, cultivation and planting of castor-oil plants in soil salinized areas, and provides a basis for application of nano-zinc oxide in economic crops, especially castor-oil plants, and improvement of the salt tolerance of the castor-oil plants.

Description

Technical Field

[0001] The invention belongs to the technical field of economic crop cultivation, and specifically designs a method for improving the salt tolerance of castor seeds based on nano zinc oxide initiation. Background Art

[0002] Castor is one of the world's top ten oil crops and a special industrial oil source crop. Seed germination is the starting point of the entire life cycle of the plant and a key stage that affects crop yield and quality. Salinity causes loss of seed vitality and reduced germination, which damages crop growth. Therefore, seeking a strategy to increase seed stress resistance is crucial to increasing crop yields.

[0003] Seed priming improves seed germination rate and tolerance to abiotic stress by changing the physiological state of water use and nutrient absorption in seeds. Due to the small size of nanoparticles, they are able to penetrate the biological barrier of the seed coat. Therefore, seed priming using nanoparticles (1-100nm) is a simple and environmentally friendly technology to achieve rapid seed germination and improve its salt tolerance.

[0004] Zinc is an essential trace element for plants and plays an important role in the resistance of crops to abiotic stress. Nano zinc oxide is non-toxic and inexpensive, and has become the most widely used nanoparticle in the world. How to use nano zinc oxide seed priming technology to improve the germination of castor seeds under salt stress and the growth of seedlings after germination is an important part of promoting the development of castor seed technology.

[0005] However, the existing initiation technology has many defects, such as cumbersome operation, high price, difficulty in cleaning the initiator and harm to the environment, which makes it difficult to be applied; and there is no report on the germination of castor seeds under salt stress after initiation. Based on the above situation, this application proposes a method for improving the salt tolerance of castor seeds based on nano zinc oxide initiation. Summary of the invention

[0006] The purpose of the present invention is to propose a method based on nano zinc oxide suspension to increase the germination rate and germination rate of castor seeds under salt stress and promote the growth of seedlings after germination. It aims to solve the problem that castor seeds have slow germination rate, low germination rate and difficult seedling growth in saline areas in Northeast China, which leads to a long seedling period and increased costs.

[0007] A method for improving the salt tolerance of castor seeds based on nano zinc oxide initiation, the method comprising the following steps:

[0008] S1. Weigh nano zinc oxide particles, add water to disperse them, and prepare a nano zinc oxide solution of a specific concentration.

[0009] S2. After fully stirring the above solution, put it into an ultrasonicator for dispersion to prepare a nano zinc oxide suspension, and pour it into a reagent bottle with a cover.

[0010] S3. Select castor seeds, disinfect them with sodium hypochlorite, immerse them in a nano zinc oxide suspension, place them in a gyroscopic oscillator, and perform a light-shielding treatment.

[0011] S4. Pour the primed castor seeds into a nylon mesh bag and place it in a ventilated place indoors to restore the seeds to their initial moisture content, thereby obtaining nano-primed castor seeds.

[0012] S5. Sowing the castor seeds after the priming treatment and subjecting them to salt stress treatments of different concentrations.

[0013] Furthermore, in step S1, the particle size of the nano zinc oxide particles is 30±10 nm, the hydrodynamic size is about 373.62 nm, and the concentration of the prepared suspension is 1000 mg / L.

[0014] Furthermore, in step S2, the ultrasonic dispersion time is 60 minutes, and the reagent bottle is turned upside down 5 times every 20 minutes.

[0015] Furthermore, in step S3, the concentration of sodium hypochlorite is 5%, the disinfection time is 10 minutes, the light shielding initiation time is 24 hours, and the rotation speed of the gyroscopic oscillator is 125 rpm.

[0016] Furthermore, in step S4, the seed drying time is 14 to 16 hours.

[0017] Furthermore, in step S5, the salt stress treatments are 50 mmol / L, 100 mmol / L and 150 mmol / L sodium chloride solutions respectively.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects:

[0019] The invention provides a method for improving the salt tolerance of castor seeds based on nano zinc oxide initiation, wherein nano zinc oxide particles of a specific concentration are dispersed in an aqueous solution, and a nano suspension thereof is prepared after ultrasonic oscillation, and is used for initiation of castor seeds. The initiation process is simple to operate, and the nano zinc oxide used for initiation is safe, pollution-free and low-priced, and is an environmentally friendly seed quality improvement technology. After initiation treatment, the germination rate and final germination rate of castor seeds under salt stress are effectively improved, and the growth of seedlings after germination is promoted. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The present invention is a schematic flow chart of a method for improving the salt tolerance of castor-oil plant based on nano zinc oxide.

[0021] Figure 2 It is a comparison chart of the daily germination of seeds of Comparative Examples 1 to 3 and Examples 1 to 3.

[0022] Figure 3 This is a comparison chart of the seedling growth on the 10th day between Comparative Example 4 and Example 4.

[0023] Figure 4 This is a comparison of DAB and NBT chemical tissue staining of the cotyledons of the 21st day seedlings of Comparative Example 4 and Example 4. Specific implementation methods

[0024] like Figure 1 In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0025] The test materials of the following examples are: Fenbi No. 7 castor seeds produced by Shanxi Jingzuo Castor Technology Co., Ltd.

[0026] Example 1

[0027] The method for improving the salt tolerance of castor seeds based on nano zinc oxide initiation described in the present invention is specifically to weigh 30±10nm zinc oxide and add water to prepare a 1000mg / L aqueous solution, fully stir and then put it into ultrasound for dispersion for 60min to prepare a nano zinc oxide suspension. Select Fenbi No. 7 seeds with about half the volume of the suspension, disinfect them with 5% sodium hypochlorite for 10min, wash them with distilled water for 5 times, and then immerse them in the 1000mg / L nano zinc oxide suspension, place them in a gyroscopic oscillator, and initiate them for 24h at a speed of 125rpm under light shielding. Then pour the seeds into a nylon mesh bag and place them in a ventilated place indoors for 14-16h to restore the seeds to the initial water content. Castor seeds after nano initiation are obtained. Every 30 seeds are placed in a culture dish with a diameter of 11cm, and filter paper is moistened with 50mmol / L sodium chloride solution for 10d. During this period, the filter paper is updated every 2d to prevent salt accumulation, and 4 repetitions are set. All seeds were grown in a seed incubator at 25 ± 1 °C with a photoperiod of 12 h and were considered to have germinated when the radicle was larger than 2 mm.

[0028] Example 2

[0029] The method for improving the salt tolerance of castor seeds based on nano zinc oxide initiation described in the present invention is specifically to weigh 30±10nm zinc oxide and add water to prepare a 1000mg / L aqueous solution, fully stir and then put it into ultrasound for dispersion for 60min to prepare a nano zinc oxide suspension. Select Fenbi No. 7 seeds with about half the volume of the suspension, disinfect them with 5% sodium hypochlorite for 10min, wash them with distilled water for 5 times, and then immerse them in the 1000mg / L nano zinc oxide suspension, place them in a gyroscopic oscillator, and initiate them for 24h at a speed of 125rpm under light shielding. Then pour the seeds into a nylon mesh bag and place them in a ventilated place indoors for 14-16h to restore the seeds to the initial water content. Castor seeds after nano initiation are obtained. Every 30 seeds are placed in a culture dish with a diameter of 11cm, and filter paper is moistened with 100mmol / L sodium chloride solution for 10d. During this period, the filter paper is updated every 2d to prevent salt accumulation, and 4 repetitions are set. All seeds were grown in a seed incubator at 25 ± 1 °C with a photoperiod of 12 h and were considered to have germinated when the radicle was larger than 2 mm.

[0030] Example 3

[0031] The method for improving the salt tolerance of castor seeds based on nano zinc oxide initiation described in the present invention is specifically to weigh 30±10nm zinc oxide and add water to prepare a 1000mg / L aqueous solution, fully stir and then put it into ultrasound for dispersion for 60min to prepare a nano zinc oxide suspension. Select Fenbi No. 7 seeds with about half the volume of the suspension, disinfect them with 5% sodium hypochlorite for 10min, wash them with distilled water 5 times, and then immerse them in the 1000mg / L nano zinc oxide suspension, place them in a gyroscopic oscillator, and initiate them for 24h at a speed of 125rpm under light shielding. Then pour the seeds into a nylon mesh bag and place them in a ventilated place indoors for 14-16h to restore the seeds to the initial water content. Castor seeds after nano initiation are obtained. Every 30 seeds are placed in a culture dish with a diameter of 11cm, and filter paper is moistened with a 150mmol / L sodium chloride solution for 10d. During this period, the filter paper is updated every 2d to prevent salt accumulation, and 4 repetitions are set. All seeds were grown in a seed incubator at 25 ± 1 °C with a photoperiod of 12 h and were considered to have germinated when the radicle was larger than 2 mm.

[0032] Example 4

[0033] The method for improving the salt tolerance of castor seeds based on nano zinc oxide initiation disclosed by the present invention is specifically to weigh 30±10nm zinc oxide and add water to prepare a 1000mg / L aqueous solution, fully stir and then put it into ultrasound for dispersion for 60min to prepare a nano zinc oxide suspension. Select Fenbi No. 7 seeds with about half the volume of the suspension, disinfect them with 5% sodium hypochlorite for 10min, wash them with distilled water for 5 times, and then immerse them in the 1000mg / L nano zinc oxide suspension, place them in a gyroscopic oscillator, and initiate them for 24h at a speed of 125rpm under light shielding. Then pour the seeds into a nylon mesh bag and place them in a ventilated place indoors for 14-16h to restore the seeds to the initial water content. Castor seeds after nano initiation are obtained. Every 16 seeds are placed in a hole tray filled with soil (vermiculite: soil=2:1) ​​and cultured for 21d, and 4 repetitions are set. During this period, a 100mmol / L sodium chloride solution is used to keep the soil moist but without water accumulation. All seeds were grown in a plant culture room at 25 ± 1 °C with a photoperiod of 12 h.

[0034] Comparative Example 1

[0035] The difference between Comparative Example 1 and Example 1 is that the comparative example directly uses unprimed seeds to carry out the test.

[0036] Comparative Example 2

[0037] The difference between Comparative Example 2 and Example 2 is that the comparative example directly uses unprimed seeds to carry out the test.

[0038] Comparative Example 3

[0039] The difference between Comparative Example 3 and Example 3 is that the comparative example directly uses unprimed seeds to carry out the test.

[0040] Comparative Example 4

[0041] The difference between Comparative Example 4 and Example 4 is that the comparative example directly uses unprimed seeds to carry out the test.

[0042] The result statistics are as follows:

[0043] From Table 1 and Figure 2It can be seen that compared with the unprimed seeds in the comparative example, after being primed by 1000 mg / L nano zinc oxide suspension, the germination index of castor seeds under salt stress was greatly improved, and was increased by 34.87%, 166.56% and 521.62% under the treatment of 50 mmol / L, 100 mmol / L and 150 mmol / L sodium chloride solution, respectively, and the final germination rate increased by 19.05%, 158.36% and 600.90%, respectively, and the germination rate was significantly improved. The relative persecution rate under salt stress decreased by 160.70%, 59.99% and 27.08%, respectively, indicating that the nano zinc oxide initiation treatment effectively improved the salt tolerance of castor seeds.

[0044] As shown in Table 2, compared with the unprimed seeds of the comparative example, after being primed by 1000 mg / L nano zinc oxide suspension, the malondialdehyde content of castor seeds under salt stress was significantly reduced, and decreased by 26.08% under the treatment of 100 mmol / L sodium chloride solution, reaching the minimum value under salt stress treatment, while the soluble sugar and proline contents increased by 37.21% and 37.12%, respectively. Compared with the unprimed seeds of the comparative example, after being primed by 1000 mg / L nano zinc oxide suspension, the POD and APX antioxidant enzyme activities of castor seeds under the treatment of 100 mmol / L sodium chloride solution decreased, indicating that nano zinc oxide priming effectively alleviated the damage of salt stress to seeds and improved the salt tolerance of castor seeds.

[0045] Depend on Figure 3 It can be seen that compared with the unprimed seeds in comparative example 4, after being primed with 1000 mg / L nano zinc oxide suspension, the germination rate, germination speed and uniformity of castor seeds in the plug tray under salt stress were significantly improved on the 10th day.

[0046] At the 21st day, compared with the unprimed seeds of Comparative Example 4, after being primed with 1000 mg / L of nano zinc oxide suspension, the growth rate and biomass of castor seedlings under salt stress were increased, and the growth state was significantly improved; as shown in Table 2, compared with the unprimed seeds of Comparative Example 4, after being primed with 1000 mg / L of nano zinc oxide suspension, when the seeds grew in the plug tray for 21 days, the leaf area of ​​the cotyledons of castor seedlings under salt stress increased by 35.53%; as shown in Table 3, compared with the unprimed seeds of Comparative Example 4, after being primed with 1000 mg / L of nano zinc oxide suspension, when the seeds grew in the plug tray for 21 days, the chlorophyll content and net photosynthesis rate of castor cotyledons under salt stress were significantly increased, by 13.68% and 53.79%, respectively; Figure 4It can be seen that compared with the unprimed seeds in comparative example 4, after being primed with 1000 mg / L nano zinc oxide suspension, on the 21st day, the DAB-stained brown spots and NBT-stained blue spots of the cotyledons of castor seedlings under salt stress were smaller in area and lighter in color, indicating that nano zinc oxide priming effectively improved the salt tolerance of castor seedlings, thereby improving the quality of seedlings under salt stress and saving costs for castor seedling cultivation under adverse conditions.

[0047] Table 1 Effects of nano zinc oxide priming on castor seed germination parameters under salt stress

[0048]

[0049] Table 2 Effects of nano-zinc oxide priming on osmotic regulating substances and antioxidant enzyme activities in castor seeds under salt stress

[0050]

[0051] Table 3 Effects of nano zinc oxide priming on leaf area of ​​castor seedling cotyledons under salt stress

[0052]

[0053] Table 4 Effects of nano-zinc oxide priming on photosynthetic parameters of castor seedling cotyledons under salt stress

[0054]

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles and purpose of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for improving the salt tolerance of castor seeds based on nano zinc oxide, characterized in that: The method comprises the following steps: S1. Weigh nano zinc oxide particles and add water to prepare a solution of a specific concentration; S2, placing the above solution in an ultrasonic device for ultrasonic dispersion to prepare a nano zinc oxide suspension; S3, select castor seeds, immerse them in nano zinc oxide suspension, and induce by oscillation and light shielding; S4, pouring the primed castor seeds into a nylon mesh bag and drying them indoors to the initial moisture content of the seeds; S5. Castor seeds after sowing were subjected to salt stress treatments of different concentrations.

2. A method for improving the salt tolerance of castor seeds based on nano zinc oxide according to claim 1, characterized in that: In the step S1, the particle size of the nano zinc oxide is 30±10 nm, the hydrodynamic size thereof is about 373.62 nm, and the concentration of the prepared suspension is 1000 mg / L.

3. A method for improving the salt tolerance of castor seeds based on nano zinc oxide according to claim 1, characterized in that: In step S2, the ultrasonic dispersion time is 60 minutes, and the reagent bottle is turned upside down 5 times every 20 minutes.

4. A method for improving the salt tolerance of castor seeds based on nano zinc oxide initiation according to claim 1, characterized in that: In step S3, the volume ratio of the nano suspension to castor seeds should be greater than 2:1, and the light shielding initiation time is 24 hours.

5. A method for improving the salt tolerance of castor seeds based on nano zinc oxide initiation according to claim 1, characterized in that: In step S4, the indoor drying time is 14 to 16 hours.

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