A method for promoting germination of hard-coated seeds and use thereof

Abstract

This invention relates to a method for promoting the germination of hard-shelled seeds and its application, belonging to the field of seed and seedling propagation technology. The invention softens the seed coat by treating with concentrated sulfuric acid, enhancing permeability; then, through a dry-wet treatment, the hard shell cracks, improving water absorption and aeration; finally, it combines GA3 and variable-temperature germination to break dormancy, shortening germination time and increasing germination rate. Taking cypress trees as an example, the shell cracking rate after concentrated sulfuric acid treatment reaches over 77.17%, increasing to 86.87% after dry-wet treatment, without affecting seed viability. This method resulted in germination rates of 64.68% and 63.78% for *Juniperus chinensis* and *Juniperus qilianense*, respectively, significantly higher than the control. This invention maintains high embryo viability while improving shell cracking and germination rates; it is simple to operate, low in cost, and has good prospects for widespread application.

Description

Technical Field

[0001] This invention belongs to the field of seedling propagation technology, specifically relating to a method for promoting the germination of hard-shelled seeds and its application. Background Technology

[0002] Hard-shelled seeds refer to seeds with hard seed coats and poor permeability, commonly found in plants of the Pinaceae and Cupressaceae families. Due to the mechanical confinement and air-permeability obstruction of the seed coat, these seeds generally suffer from long germination cycles and low germination rates. Without treatment, they often take several years to germinate, severely limiting seedling efficiency. Taking Cupressaceae plants as an example, their seeds have hard, dense seed coats with poor air permeability, and the embryo requires after-ripening to develop. Therefore, a long period of pre-germination treatment is necessary before sowing. Untreated seeds typically take 2-3 years to germinate after sowing, and the germination rate is low and the seedlings are not uniform, resulting in high seedling costs and low propagation coefficients, making it difficult to meet the needs of afforestation and landscaping.

[0003] Currently, common methods for promoting germination include mechanical shell cracking, low-temperature stratification, warm water soaking, and dilute sulfuric acid corrosion. While these methods can shorten germination time to some extent, they still present problems such as low shell cracking rate, easy damage to the embryo, or limited improvement in germination rate for hard-shelled seeds with particularly dense seed coats. Summary of the Invention

[0004] The purpose of this invention is to address the current problems in existing methods for promoting the germination of hard-shelled seeds, such as low shell cracking rates, easy damage to the embryo, or limited improvement in germination rates. This invention aims to provide a treatment scheme for hard-shelled seeds that can effectively break down the seed shell barrier while maintaining embryo viability and significantly improving germination rates. Therefore, this invention provides a method for promoting the germination of hard-shelled seeds and its application.

[0005] This invention provides a method for promoting the germination of hard-shelled seeds, comprising the following steps: After removing the pericarp, the hard-shelled seeds are soaked in concentrated sulfuric acid for 10-15 minutes, then washed with water and dried to obtain seeds treated with concentrated sulfuric acid. The seeds treated with concentrated sulfuric acid were subjected to dry and wet treatments to obtain cracked-shell seeds; The wet-dry treatment includes: soaking the seeds treated with concentrated sulfuric acid to absorb water, and then drying the soaked seeds; one soaking and one drying constitute one wet-dry treatment, and the wet-dry treatment is performed at least once; The cracked seeds were soaked in a 300-500 mg / L gibberellin GA3 solution for 20-30 h, washed with water, and then placed in a variable temperature environment for germination. The variable temperature environment is as follows: first place it at 4~8℃ for 5~7 days, then place it at 22~25℃ for 5~7 days, and repeat this cycle.

[0006] Preferably, the hard-shelled seeds are hard-shelled seeds of cypress trees.

[0007] Preferably, the cypress plant is Juniperus macrocarpa or Juniperus chinensis 'Qilian'.

[0008] Preferably, the drying temperature in the wet-dry treatment is 30~50℃, and the drying time is 10~12 h / time.

[0009] Preferably, the soaking and water absorption time in the dry and wet treatment is 12-14 hours per cycle.

[0010] Preferably, the drying is variable-temperature drying; the variable-temperature drying includes: First, dry at 30~35℃ for 5~6 hours, then raise the temperature to 45~50℃ and dry for another 5~6 hours.

[0011] Preferably, the concentrated sulfuric acid has a mass concentration of ≥95%.

[0012] Preferably, the volume ratio of concentrated sulfuric acid to seeds in the concentrated sulfuric acid soaking treatment is 2:1.

[0013] Preferably, before the concentrated sulfuric acid soaking treatment, a seed screening step is included, which includes: soaking the hard-shelled seeds with the pericarp removed in warm water to remove the unripe seeds and empty-shelled seeds floating on the water surface.

[0014] Preferably, after the gibberellin GA3 solution soaking treatment, it is further subjected to HgCl2 soaking sterilization treatment for 8-12 minutes.

[0015] Beneficial effects: This invention provides a method for promoting the germination of hard-shelled seeds, comprising the following steps: Hard-shelled seeds with the pericarp removed are soaked in concentrated sulfuric acid for 10-15 minutes, then washed with water and air-dried to obtain sulfuric acid-treated seeds. The sulfuric acid-treated seeds are then subjected to a wet-dry treatment to obtain cracked-shell seeds. The wet-dry treatment includes: soaking the sulfuric acid-treated seeds to absorb water, and then drying the soaked seeds. One soaking and one drying constitute one wet-dry treatment, and the wet-dry treatment is performed at least once. The cracked-shell seeds are then soaked in a 300-500 mg / L gibberellin GA3 solution for 20-30 hours, washed with water, and then placed in a variable-temperature environment for germination. The variable-temperature environment is: first placed at 4-8℃ for 5-7 days, then placed at 22-25℃ for 5-7 days, and this cycle is repeated. This invention first treats the seeds with concentrated sulfuric acid to soften the hard-shelled seed coat and increase the permeability of the seed coat cells; then, the soaked and swollen seeds undergo a wet-dry treatment to crack the hard shell, increasing the seeds' water absorption and air permeability; finally, GA3 treatment and variable-temperature germination break seed dormancy, shorten the seed germination time, and improve the seed germination rate.

[0016] Taking *Juniperus macrocarpa* and *Juniperus qilianense*, both belonging to the Cupressaceae family, as examples, the seed cracking rate treated with concentrated sulfuric acid according to this invention reached over 77.17%, significantly higher than the control's 37.74%. After variable-temperature drying treatment, the cracking rate further increased to 86.87%. The seed viability after concentrated sulfuric acid treatment showed no significant difference compared to the control, indicating that concentrated sulfuric acid treatment did not affect seed activity and maintained high embryo activity. Regarding germination, the germination rate of *Juniperus macrocarpa* seeds treated with this method reached 64.68%, and that of *Juniperus qilianense* seeds reached 63.78%, both significantly higher than the control. In summary, this method significantly improves both cracking and germination rates while maintaining high embryo activity. Furthermore, it is simple to operate, low in cost, and has good prospects for widespread application. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0017] Figure 1 A schematic diagram of the embryo of a large-fruited juniper seed; Figure 2 Image showing the TTC staining results of seed embryos from Juniperus macrocarpa var. macrocarpa. Figure 3 The diagram shows the seeds of *Juniperus chinensis* after treatment; where A is a diagram of seeds treated with concentrated sulfuric acid, and B is a diagram of seeds treated with the control group. Figure 4 A schematic diagram of the cracked shell of a large-fruited juniper seed; Figure 5The images show the germination results of hard-shelled seeds (scale bar is 1cm); where A is the germination result of the large-fruited juniper seed treatment group soaked in concentrated sulfuric acid for 10 min in Example 1, B is the germination result of the large-fruited juniper seed control group in Example 1, C is the germination result of the large-fruited juniper seed treatment group soaked in concentrated sulfuric acid for 10 min in Example 2, D is the germination result of the large-fruited juniper seed control group in Example 2, E is the germination result of the large-fruited juniper seed in Example 3, and F is the germination result of the Qilian juniper seed in Example 4. Detailed Implementation

[0018] This invention provides a method for promoting the germination of hard-shelled seeds, comprising the following steps: After removing the pericarp, the hard-shelled seeds are soaked in concentrated sulfuric acid for 10-15 minutes, then washed with water and dried to obtain seeds treated with concentrated sulfuric acid. The seeds treated with concentrated sulfuric acid were subjected to dry and wet treatments to obtain cracked-shell seeds; The wet-dry treatment includes: soaking the seeds treated with concentrated sulfuric acid to absorb water, and then drying the soaked seeds; one soaking and one drying constitute one wet-dry treatment, and the wet-dry treatment is performed at least once; The cracked seeds were soaked in a 300-500 mg / L gibberellin GA3 solution for 20-30 h, washed with water, and then placed in a variable temperature environment for germination. The variable temperature environment is as follows: first place it at 4~8℃ for 5~7 days, then place it at 22~25℃ for 5~7 days, and repeat this cycle.

[0019] The method of this invention significantly improves the shell cracking rate and germination rate while maintaining the high activity of the embryo. It is also simple to operate, low in cost, and has good prospects for widespread application.

[0020] The present invention involves soaking hard-shelled seeds with the pericarp removed in concentrated sulfuric acid for 10-15 minutes, then washing with water and drying to obtain seeds treated with concentrated sulfuric acid.

[0021] In one embodiment, the hard-shelled seeds of the present invention are hard-shelled seeds of cypress trees.

[0022] As one embodiment, the cypress plant described in this invention is either Juniperus macrocarpa or Juniperus chinensis 'Qilian'.

[0023] As one embodiment, the concentrated sulfuric acid of the present invention has a mass concentration of ≥95%.

[0024] In one embodiment, the volume ratio of concentrated sulfuric acid to seeds in the concentrated sulfuric acid soaking treatment of the present invention is 2:1. Specifically, the concentrated sulfuric acid soaking treatment of the present invention involves: placing the selected plump seeds in a beaker, slowly pouring in concentrated sulfuric acid, and treating for 10-15 minutes; after treatment, rinsing the seeds 4-5 times with tap water, rubbing them by hand to remove impurities, rinsing them again 4-5 times with distilled water, soaking them overnight, and then air-drying them for later use.

[0025] In one embodiment, prior to the concentrated sulfuric acid soaking treatment, the present invention includes a seed screening step, which comprises: soaking the hard-shelled seeds (with the pericarp removed) in warm water to remove unripe seeds and empty-shelled seeds floating on the water surface. In another embodiment, the seed screening step further includes: removing external impurities and discarding damaged, insect-hole-filled, and excessively small seeds.

[0026] After obtaining seeds treated with concentrated sulfuric acid, the present invention performs dry and wet treatment on the seeds treated with concentrated sulfuric acid to obtain cracked seeds.

[0027] In one embodiment, the wet-dry treatment of the present invention includes: soaking seeds treated with concentrated sulfuric acid to absorb water, and then drying the soaked seeds; one soaking and one drying constitute one wet-dry treatment, and the wet-dry treatment is performed at least once. In one embodiment, the wet-dry treatment of the present invention is repeated continuously for 1 to 2 weeks.

[0028] In one embodiment, the drying temperature in the wet-dry treatment of the present invention is 30~50℃, and the drying time is 10~12 h / time.

[0029] In one embodiment, the soaking and water absorption time in the dry and wet treatment of the present invention is 12-14 hours per cycle. In another embodiment, the soaking and water absorption time in the dry and wet treatment of the present invention is 14 hours per cycle.

[0030] In one embodiment, the drying method described in this invention is constant temperature drying, wherein the temperature is 35~40℃ and the drying time is 10~12 h / cycle. In another embodiment, the temperature for constant temperature drying is 35℃ and the drying time is 10 h / cycle.

[0031] As one implementation method, the drying described in this invention is variable-temperature drying; the variable-temperature drying includes: First, dry at 30-35°C for 5-6 hours, then raise the temperature to 45-50°C and dry for another 5-6 hours. Alternatively, dry at 30°C for 5-6 hours, then raise the temperature to 50°C and dry for another 5-6 hours.

[0032] After obtaining the cracked seeds, the present invention soaks the cracked seeds in a 300-500 mg / L gibberellin GA3 solution for 20-30 h, washes them with water, and then places them in a variable temperature environment for germination.

[0033] In one embodiment, the seeds with cracked shells are soaked in a 400 mg / L gibberellin (GA3) solution for 24 h. In another embodiment, the temperature-changing environment is as follows: first, the seeds are placed at 4–8°C for 5–7 days, then at 22–25°C for 5–7 days, and this cycle is repeated. In yet another embodiment, the temperature-changing environment is as follows: first, the seeds are placed at 4°C for one week, then at 25°C for one week, and this cycle is repeated. In one embodiment, after the gibberellin (GA3) solution soaking treatment, the seeds are further subjected to HgCl2 sterilization treatment for 8–12 min. In one embodiment, the HgCl2 solution used for sterilization treatment has a mass concentration of 2%. After sterilization, the seeds are washed 5–8 times with sterile distilled water.

[0034] As one implementation method, this invention uses *Juniperus macrocarpa* and *Juniperus qilianense* as examples for verification. The seed cracking rate after treatment with concentrated sulfuric acid according to this invention can reach over 77.17%, significantly higher than the control's 37.74%. After variable-temperature drying treatment, the cracking rate of the proposed method further increases to 86.87%. As another implementation method, the seed viability after concentrated sulfuric acid treatment according to this invention is not significantly different from the control, indicating that concentrated sulfuric acid treatment has no effect on seed activity and can maintain high embryo activity. As yet another implementation method, the germination rate of *Juniperus macrocarpa* seeds treated by the method of this invention can reach 64.68%, and the germination rate of *Juniperus qilianense* seeds can reach 63.78%, both significantly higher than the control.

[0035] To further illustrate the present invention, the following detailed description, in conjunction with the accompanying drawings and embodiments, provides a method for promoting the germination of hard-shelled seeds and its applications, but these descriptions should not be construed as limiting the scope of protection of the present invention.

[0036] The following are some of the general experimental methods used in the embodiments of the present invention. Unless otherwise specified, they are all conventional methods.

[0037] 1. Seed embryo percentage detection The collected fruits of *Juniperus chinensis* or *Juniperus kelianense* (collected from Langkazi County, Tibet Autonomous Region, 28°51′34″N, 90°32′1″E, altitude 4409 m) were soaked in tap water to remove the pericarp, and the seeds were then dried. Next, the dried seeds were soaked in warm water, removing any unripe or empty seeds floating on the surface, as well as any external impurities, defects, insect holes, and excessively small seeds. The seeds were then pried open to check their plumpness, and the embryo-bearing rate was calculated according to Formula I: Embryo survival rate = Number of intact embryos / Total number of seeds × 100%, Equation I.

[0038] The results showed that the seeds of *Juniperus macrocarpa* had two types of embryos: incomplete embryos (lignified embryos and immature embryos) and complete embryos. Figure 1 The embryo-bearing rates were 54.39% (batch 1 of Example), 58.75% (batch 2 and 3 of Example), and 66.52% (batch 4 of Example) (Table 1).

[0039] Table 1 Seed Embryo Preservation Rate

[0040] 2. Seed viability testing Peel off the seed coat, cut open the seed coat with a scalpel, leaving the embryo intact, soak the seeds in 1% TTC, and stain them in a 35°C oven in the dark for 2 hours. Examine the embryo staining. Figure 2 Seeds whose embryos are stained red are considered viable. The formula for calculating seed viability is shown in Equation II: Seed viability = number of viable seeds / total number of seeds × 100%, Equation II.

[0041] Example 1 Methods and effects of combining concentrated sulfuric acid treatment with constant temperature dry and wet treatment This embodiment provides a method for treating large-fruited juniper seeds with a cracked shell to promote germination and maintain high embryo activity, including the following steps: (1) Concentrated sulfuric acid treatment: Place the selected plump seeds in a beaker, slowly pour in 98% concentrated sulfuric acid, the volume ratio of concentrated sulfuric acid to seeds is 2:1, treat for 10 min, rinse with tap water, soak the seeds overnight, rub by hand to remove impurities, rinse with distilled water 5 times, and then air dry for later use. Figure 3 A). The control group (CK) was soaked in distilled water and not treated with concentrated sulfuric acid. Figure 3 B).

[0042] (2) Dry and wet treatment: Seeds treated with concentrated sulfuric acid were soaked in distilled water for 14 hours, then dried in an oven at 35℃ for 10 hours. This treatment was repeated for 2 weeks. The degree of seed shell cracking was recorded. Figure 4(Table 2) Cracking rate = number of cracked seeds / total number of seeds treated × 100%. The cracking rate of the control (CK) seeds was 37.74%, while the cracking rate of the seeds treated with concentrated sulfuric acid was 77.17%, indicating that the cracking rate of the seeds treated with concentrated sulfuric acid was significantly higher than that of the control.

[0043] (3) Seed viability test: According to the aforementioned seed viability test method, the seed viability of the control CK was 90.00%, and the seed viability of the concentrated sulfuric acid treated seed was 93.55%. The difference in seed activity between the concentrated sulfuric acid treated seed and the control seed was not significant, indicating that the concentrated sulfuric acid treatment for 10 min had no effect on seed activity and could maintain the previous viability of the embryo (Table 3).

[0044] (4) Seed germination: Cracked seeds were treated with 400 mg / L GA3 for 24 h, sterilized with 2% HgCl2 for 12 min, washed 5-8 times with sterile distilled water, and placed in sterile filter paper petri dishes. The mixture was then placed at 4℃ for one week, then at 25℃ for one week, and this cycle was repeated. After 3 months, the seeds treated with concentrated sulfuric acid began to germinate. Figure 5 A), the germination rate was 30.21% (calculated based on an embryonic rate of 54.39%, Table 4), while the germination rate of the control group (CK) was 2.63%. Figure 5 B).

[0045] Comparative Example 1 Treat 100 seeds with concentrated sulfuric acid alone. This comparative example provides a treatment method for large-fruited juniper seeds. Compared with the treatment group in Example 1, the only difference is that the dry and wet treatment in step (2) and the GA3 treatment in step (4) are omitted. That is, the seeds treated with concentrated sulfuric acid are washed with water and then placed directly in a variable temperature environment for germination. The results show that only a few out of 100 seeds germinate, with a germination rate of less than 2%.

[0046] Comparative Example 2 GA3 treatment alone (100 seeds) This comparative example provides a treatment method for large-fruited juniper seeds. Compared with the treatment group in Example 1, the only difference is that the concentrated sulfuric acid treatment in step (1) and the dry-wet treatment in step (2) are omitted. That is, the plump seeds after screening are directly subjected to GA3 treatment and variable temperature germination in step (4). The results show that only a few out of 100 seeds germinate, and the germination rate is less than 2%.

[0047] Example 2 Methods and effects of combining concentrated sulfuric acid treatment with variable temperature dry and wet treatment In this embodiment, the treatment method for large-fruited juniper seeds is the same as in Example 1, except that the temperature for the dry-wet treatment is variable temperature treatment, i.e., 30℃ for 5-6 h and 50℃ for 5-6 h. The large-fruited juniper seeds in this embodiment were collected from different batches than those in Example 1, and the embryo-bearing rate was 58.75% (Table 1). After variable temperature treatment, the shell cracking rate of the control (CK) was 69.57%, and the shell cracking rate after 10 min of concentrated sulfuric acid treatment was 86.87%, both significantly higher than the shell cracking rate of the constant temperature treatment in Example 1 (Table 2). Seed viability was 93.33% (measured before dry-wet treatment, Table 3), not significantly different from that in Example 1. Seeds treated with variable temperature dry-wet treatment began to germinate after 50 days. Figure 5 C, 5D), the seeds germinated 40 days earlier than those treated with constant temperature. The germination rate of the control (CK) was 48.79%, and the germination rate of the seed treated with concentrated sulfuric acid for 10 min was 64.68%, both of which were significantly higher than the germination rate in Example 1 (Table 4).

[0048] Example 3 Optimal methods and effects of concentrated sulfuric acid treatment time In this embodiment, the method for treating large-fruited juniper seeds is the same as in Embodiment 2, except that the concentrated sulfuric acid treatment time is 15 minutes. Germination begins after 50 days. Figure 5 E), the seed germination rate was 63.55%, slightly lower than the seed germination rate after 10 min of concentrated sulfuric acid treatment, indicating that 10 min of concentrated sulfuric acid treatment is sufficient (Table 4).

[0049] Example 4 Application and effects of the method of the present invention in Qilian juniper In this embodiment, the method for treating hard-shelled seeds is the same as in Example 2, except that the seeds used in this embodiment are *Juniperus chinensis* seeds from Qilian, with an embryogenic rate of 66.52% (Table 1), slightly higher than that of *Juniperus macrocarpa* seeds in Example 2. The seeds were treated with concentrated sulfuric acid for 10 min, rinsed with tap water, and subjected to varying temperatures for both wet and dry treatment (30℃ for 5-6 h, 50℃ for 5-6 h). The seed shell cracking rate of *Juniperus chinensis* seeds was 74.00% (Table 2). Seed viability was 91.89% (measured before wet and dry treatment, Table 3), not significantly different from that of *Juniperus macrocarpa* seeds. The germination rate of *Juniperus chinensis* seeds from Qilian was 63.78% (Table 4). Figure 5 F), similar to the germination rate of large-fruited juniper seeds.

[0050] The statistical results of seed shell cracking rates in each embodiment are shown in Table 2. In Example 1, the shell cracking rate of seeds treated with concentrated sulfuric acid was 77.17%, significantly higher than the control CK of 37.74%. In Example 2, under variable temperature and dry-wet conditions, the shell cracking rate of seeds treated with concentrated sulfuric acid reached 86.87%, further improving compared to the constant temperature treatment in Example 1. In Example 4, the shell cracking rate of Qilian Juniper seeds was 74.00%, indicating that the method of the present invention has a good shell cracking promoting effect on seeds of different Juniper species.

[0051] Table 2 Seed Cracking Rate

[0052] The seed viability test results for each embodiment are shown in Table 3. In Example 1, the seed viability treated with concentrated sulfuric acid was 93.55%, which was not significantly different from the control (CK) at 90.00%. The seed viability in Examples 2 and 3 was 93.33%, and in Example 4, the seed viability of *Juniperus chinensis* was 91.89%. The seed viability in all embodiments remained above 90%, indicating that concentrated sulfuric acid treatment and both dry and wet treatments did not significantly damage embryo activity.

[0053] Table 3 Seed Viability Test

[0054] The statistical results of seed germination rates for each embodiment are shown in Table 4. In Example 1, the germination rate of seeds treated with concentrated sulfuric acid was 30.21%, significantly higher than the 2.63% of the control (CK). In Example 2, under variable temperature and humidity conditions, the germination rate of seeds treated with concentrated sulfuric acid reached 64.68%, more than double that of the constant temperature treatment in Example 1, and the initial germination time was shortened from 3 months to 50 days. In Example 3, the germination rate of seeds treated with concentrated sulfuric acid for 15 minutes was 63.55%, similar to the 64.68% after 10 minutes, indicating that 10 minutes of treatment time was sufficient. In Example 4, the germination rate of Qilian Juniper seeds was 63.78%, similar to that of large-fruited Juniper seeds, indicating that the method of the present invention has universality in different Juniper species.

[0055] Table 4 Seed germination rate

[0056] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for promoting the germination of hard-shelled seeds, characterized in that, Includes the following steps: After removing the pericarp, the hard-shelled seeds are soaked in concentrated sulfuric acid for 10-15 minutes, then washed with water and dried to obtain seeds treated with concentrated sulfuric acid. The seeds treated with concentrated sulfuric acid were subjected to dry and wet treatments to obtain cracked-shell seeds; The wet-dry treatment includes: soaking the seeds treated with concentrated sulfuric acid to absorb water, and then drying the soaked seeds; one soaking and one drying constitute one wet-dry treatment, and the wet-dry treatment is performed at least once; The cracked seeds were soaked in a 300-500 mg / L gibberellin GA3 solution for 20-30 h, washed with water, and then placed in a variable temperature environment for germination. The variable temperature environment is as follows: first place it at 4~8℃ for 5~7 days, then place it at 22~25℃ for 5~7 days, and repeat this cycle.

2. The method according to claim 1, characterized in that, The hard-shelled seeds are hard-shelled seeds of plants in the Cupressaceae family.

3. The method according to claim 2, characterized in that, The cypress family plants mentioned are Juniperus macrocarpa or Juniperus chinensis 'Qilian'.

4. The method according to claim 1, characterized in that, The drying temperature in the wet-dry treatment is 30~50℃, and the drying time is 10~12 h / time.

5. The method according to claim 4, characterized in that, The soaking and water absorption time in the dry and wet treatment is 12-14 hours per cycle.

6. The method according to claim 4, characterized in that, The drying process is variable-temperature drying; the variable-temperature drying includes: First, dry at 30~35℃ for 5~6 hours, then raise the temperature to 45~50℃ and dry for another 5~6 hours.

7. The method according to claim 1, characterized in that, The concentrated sulfuric acid has a mass concentration of ≥95%.

8. The method according to claim 1, characterized in that, In the concentrated sulfuric acid soaking treatment, the volume ratio of concentrated sulfuric acid to seeds is 2:

1.

9. The method according to claim 1, characterized in that, Before the concentrated sulfuric acid soaking treatment, a seed screening step is also included, which includes: soaking the hard-shelled seeds with the pericarp removed in warm water to remove the unripe seeds and empty-shelled seeds floating on the water surface.

10. The method according to claim 1, characterized in that, After being soaked in gibberellin GA3 solution, the sample is further subjected to HgCl2 immersion sterilization treatment for 8-12 minutes.

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