A method for long-term preservation of corydalis seeds and maintaining their viability

Abstract

The application discloses a method for long-term storage of Corydalis ambigua seed balls and keeping activity, and belongs to the technical field of medicinal plant cultivation. The method comprises the following steps: selecting healthy and full Corydalis ambigua seed balls, air-drying the seed balls to a water content of 58.6±0.7%, and storing the seed balls in a breathable bag in a low-temperature environment at 3-5 DEG C for long-term storage; taking out the seed balls after storage for more than 10 months, and placing the seed balls in moist fine sand for swelling and low-temperature stratification treatment at 3-5 DEG C for 20 days; and finally, carrying out temperature change cultivation to obtain uniform seed balls of Corydalis ambigua. By controlling the water content of the seed balls, cooperating with low-temperature storage and swelling stratification treatment, the germination rate of the seed balls of Corydalis ambigua is kept to be more than 85% and the emergence rate is 88%-90% after long-term storage of the seed balls of Corydalis ambigua for 10-11 months, the seed balls emerge uniformly, and the plant height reaches 3-8 cm after 20 days. The application is green and environmentally friendly, simple to operate, breaks through the limitation of the traditional fall planting window period of Corydalis ambigua, and provides key technical support for factory seedling raising and large-scale cultivation.

Description

Technical Field

[0001] This invention belongs to the field of medicinal plant cultivation technology, specifically relating to a method for long-term preservation of Corydalis bulbs and maintaining their activity. Background Technology

[0002] Corydalis rhizome (also known as Yuanhu) is a perennial herbaceous medicinal plant belonging to the genus Corydalis in the Papaveraceae family. Its tubers, a traditional Chinese medicine, are used to promote blood circulation, remove blood stasis, regulate qi, and relieve pain. They are widely used in the production of compound Danshen tablets, Yuanhu analgesic tablets, and other traditional Chinese medicine preparations. With the increasing demand for large-scale cultivation, the propagation technology of Corydalis rhizome bulbs has gained attention. Corydalis rhizome is mainly propagated through tubers (bulbs), and the quality and activity of the bulbs directly determine the cultivation yield and the quality of the medicinal material. Long-term preservation of bulbs is a crucial guarantee for its large-scale and standardized cultivation, especially for factory-scale seedling production and cross-seasonal cultivation; the technology for long-term preservation of bulb activity is a core supporting condition.

[0003] The main technical challenge in the long-term preservation of Corydalis bulbs (actually tubers) lies in their susceptibility to dryness, stuffiness, and sprouting. Currently, traditional methods such as sand storage, cool and ventilated conditions, and low-temperature refrigeration are commonly used, but these methods do not consider the bulb's moisture content. Excessive moisture content can induce premature sprouting, while excessive drying can lead to loss of activity due to dehydration. Furthermore, temperature fluctuations during storage can cause premature sprouting or frost damage. Existing preservation methods result in short storage periods and difficulty in maintaining stable activity, failing to meet the demands of large-scale industrial production for long-term bulb preservation and staggered planting. Improper storage also easily leads to bulb loss, increasing cultivation costs and hindering industry development. Therefore, there is an urgent need for a preservation method that can suppress the respiration intensity of Corydalis bulbs, maintain their weak life activities, prevent dehydration and shriveling, and restore vigorous sprouting ability after long-term storage. Developing a simple, environmentally friendly, low-cost, efficient, and stable method that can preserve Corydalis bulbs for a long time and maintain their activity is of great practical significance and application value for promoting the large-scale and standardized cultivation of Corydalis, ensuring a stable supply of medicinal materials, and reducing cultivation costs. Summary of the Invention

[0004] The purpose of this invention is to overcome the deficiencies in the existing technology and provide a method for long-term preservation of Corydalis bulbs and maintaining their activity.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A method for long-term preservation and maintaining the viability of Corydalis bulbs includes:

[0007] (1) Selecting Corydalis bulbs;

[0008] (2) The bulbs selected in step (1) are dried in a ventilated place with a moisture content of 58.6 ± 0.7%.

[0009] (3) The bulbs treated in step (2) are stored at low temperature for a long time, placed in a low temperature environment of 3-5℃.

[0010] (4) After the bulbs treated in step (3) are stored for more than 10 months, they are placed in moist fine sand and placed in a low temperature environment of 3-5℃ for low temperature absorption and low temperature stratification for 20 days.

[0011] (5) Sow the bulbs treated in step (4) in the seedling substrate and carry out variable temperature cultivation: daytime temperature 23-27℃, light 3000-5000 lx, nighttime temperature 18-22℃, dark cultivation, variable temperature cultivation for 6-20 days, and you can get Corydalis bulbs with uniform emergence.

[0012] In some embodiments, step (1) specifically involves selecting healthy, plump, and disease-free Corydalis bulbs.

[0013] In some embodiments, in step (2), the drying is carried out by natural air drying under ventilated conditions, and the moisture content of the bulbs is measured daily, with the moisture content ranging from 51.6% to 64.8%.

[0014] In some embodiments, step (3) further includes: placing the Corydalis bulbs from step (2) into a breathable bag and storing them in a refrigerated environment for low-temperature preservation.

[0015] In some embodiments, in step (4), the low-temperature swelling and low-temperature stratification specifically involve mixing or layering the Corydalis bulbs with a moist, inert, water-retaining medium; preferably, the medium is fine sand or vermiculite.

[0016] In some embodiments, in step (5), the seedling substrate has a layered structure, including: imported peat moss: vermiculite: perlite mixed substrate with a volume ratio of 2:1:1, and the Corydalis bulbs are sown at a depth of 2-4 cm.

[0017] In some embodiments, in step (5), after sowing, the soil is thoroughly watered and covered to retain moisture, maintaining an air humidity of 55-65%.

[0018] In some embodiments, in step (1), the Corydalis bulbs are sourced from the Pan'an production area of ​​Zhejiang Province.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1) This invention innovatively develops a method for long-term preservation and maintaining the activity of Corydalis bulbs without the use of chemical reagents, which has the advantages of being green, environmentally friendly, low-cost, and highly efficient. Steps such as bulb selection, drying, low-temperature preservation, imbibition and low-temperature stratification induction, and variable-temperature cultivation can all be automated, saving time and labor, and are suitable for industrial-scale cultivation of Corydalis seedlings.

[0021] 2) This invention effectively extends the shelf life of Corydalis bulbs to 10-11 months by optimizing key parameters such as moisture content, low-temperature imbibition and stratification time, and variable-temperature cultivation time. After storage, the germination rate remains above 85%, and the seedling emergence rate reaches above 88%. This method enables long-term, cross-seasonal storage of bulbs from May harvest to April-May of the following year, breaking the limitations of the traditional autumn sowing window. It provides flexible production scheduling for factory-scale seedling production, facilitating adjustments to planting scale based on market demand. This is of great significance for the large-scale, standardized cultivation of Corydalis and the stability of the medicinal herb supply chain.

[0022] 3) Based on long-term preservation, this invention significantly shortens the germination time after sowing by combining low-temperature imbibition and low-temperature stratification treatment with variable-temperature cultivation. The germination uniformity reaches over 90%, and the plant height reaches 3-8 cm in 20 days, providing clear parameters for the standardized management of Corydalis yanhusuo factory seedling production. Attached Figure Description

[0023] Figure 1 The images show the state of Corydalis bulbs with a moisture content of 72.3±1.2% after 10 months of storage at room temperature and the seedlings after variable temperature cultivation: A is Corydalis bulbs after 10 months of storage at room temperature (25 ℃); B is Corydalis bulbs after 10 months of storage at low temperature (3-5 ℃); C is the growth of bulbs after 10 days of variable temperature cultivation after low temperature storage.

[0024] Figure 2 The images show the state of Corydalis bulbs with a moisture content of 64.8±0.3% after 10 months of low-temperature (3-5 ℃) storage and seedlings after variable-temperature cultivation: A shows bulbs stored at low temperature (3-5 ℃) for 10 months; B, C, and D show the overall growth of Corydalis after 7, 12, and 20 days of variable-temperature cultivation, respectively; E and F show the growth of individual plants after 12 and 20 days of variable-temperature cultivation.

[0025] Figure 3 The images show the state of Corydalis bulbs with a moisture content of 58.6±0.7% after 10 months of low-temperature (3-5 ℃) storage and seedlings after variable-temperature cultivation: A. Bulbs stored at low temperature (3-5 ℃) for 10 months; B. Bulbs after low-temperature imbibition and low-temperature stratification; C, D, and E show the overall growth of Corydalis after 7, 12, and 20 days of variable-temperature cultivation, respectively; F and G show the growth of individual plants after 12 and 20 days of variable-temperature cultivation.

[0026] Figure 4 The images show the state of Corydalis bulbs with a moisture content of 58.6±0.7% after 11 months of low-temperature (3-5 ℃) storage and seedlings after variable-temperature cultivation: A shows bulbs stored at low temperature (3-5 ℃) for 11 months; B shows bulbs after low-temperature imbibition and low-temperature stratification; C, D, and E show the overall growth of Corydalis after 7, 12, and 20 days of variable-temperature cultivation, respectively; F and G show the growth of individual plants after 12 and 20 days of variable-temperature cultivation.

[0027] Figure 5 The state of Corydalis bulbs with a moisture content of 51.6±1.2% after 10 months of low-temperature (3-5 ℃) storage (A) and bulbs after low-temperature swelling and low-temperature stratification (B). Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the invention is further described below with reference to specific embodiments. Unless otherwise described in detail, the technical means used in the following embodiments are all conventional means well known to those skilled in the art, or are performed according to the kit and product instructions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0029] In the following examples, the Corydalis bulbs were sourced from Pan'an, Zhejiang Province, and harvested in May. The bulbs were then placed in breathable bags and air-dried in a well-ventilated area. During the air-drying period, samples were taken daily to measure the moisture content of the bulbs. The air-drying time was controlled to ensure the bulbs reached the target moisture content set in each example. When the bulbs were air-dried until the outer skin turned slightly white, the moisture content was typically around 65%. Continuing to air-dry further reduced the moisture content. The experiments for the following examples began in early June of that year.

[0030] Calculation of bulb moisture content: Take a portion of Corydalis bulbs, weigh them, record the fresh weight, and place them in an oven at 80 ℃ to dry to constant weight. Moisture content = (fresh weight - constant weight) × 100% / fresh weight.

[0031] Germination rate calculation: After low-temperature induction, Corydalis bulbs are sown in a seedbed. Germination is indicated when the bud breaks through the substrate surface and obvious green seedling tissue is visible. Germination rate = (Number of germinations / Number of seeds sown) × 100%.

[0032] The low-temperature swelling and low-temperature stratification treatment method is as follows: Take out the Corydalis bulbs after low-temperature preservation and put them into moist fine sand. The moisture content of the moist fine sand should be such that it can be formed into a ball when squeezed by hand and crumbles easily when released. Then, place the mixture of bulbs and moist sand in a low-temperature environment of 3-5℃ for 20 days.

[0033] Example 1: Screening of moisture content for long-term storage of Corydalis bulbs

[0034] Using Corydalis bulbs harvested in Pan'an, Zhejiang Province as material, approximately 100 healthy Corydalis bulbs with buds were selected for each treatment. The bulbs, with a moisture content of 72.3±1.2% or higher, were mixed with dry fine sand, placed in breathable bags, and stored at 25℃ and low temperature (3-5℃) respectively. After approximately 10 months of storage (early April of the following year), all bulbs stored at 25℃ became empty and shriveled. Figure 1 A) All bulbs stored at low temperature germinated, and the buds were 2-3 cm long. Figure 1 B). Germinated bulbs, after being stored at low temperature, are sown in a seedling substrate consisting of imported peat moss, vermiculite, and perlite in a volume ratio of 2:1:1. The sowing depth is 2-4 cm in pots with a diameter of 6.5 cm × 6.5 cm. After sowing, water thoroughly and cover to retain moisture, maintaining an air humidity of 55-65%. Subsequently, variable-temperature cultivation is carried out. The variable-temperature cultivation conditions are: 25℃ during the day, 3000-5000 lx light, and 18℃ at night, in the dark. After 10 days, the plant height reaches approximately 5 cm. Figure 1 (C) No roots were formed, and the mother bulb began to shrivel, with the above-ground parts starting to wither. The above experimental results indicate that Corydalis bulbs with a moisture content exceeding 72.3±1.2% are not suitable for long-term storage.

[0035] Example 2: Screening of moisture content for long-term storage of Corydalis bulbs (64.8±0.3%)

[0036] Using Corydalis bulbs harvested in Pan'an, Zhejiang Province as material, approximately 100 healthy Corydalis bulbs with buds were selected for each treatment. The bulbs with a moisture content of 64.8±0.3% were mixed with dry fine sand, placed in breathable bags, and stored at 25 ℃ and low temperature (3-5 ℃) respectively. After 10 months of storage, all bulbs stored at low temperature germinated, with a germination rate of 87.3±1.3%, and the bud length was 0.1-0.6 cm. Figure 2 A).

[0037] Germinated bulbs preserved at low temperatures were selected for variable-temperature cultivation. The germinated bulbs were sown in a seedling substrate consisting of an imported peat moss:vermiculite:perlite mixture in a volume ratio of 2:1:1. The sowing depth was 2-4 cm in pots with a diameter of 6.5 cm × 6.5 cm. After sowing, the bulbs were thoroughly watered and covered to maintain humidity at 55-65%. The variable-temperature cultivation conditions were: 25°C during the day, 3000-5000 lx light, and 18°C ​​at night, in the dark. The results of potted observations are as follows: germination began after 7 days of cultivation (…). Figure 2 B); After 12 days, it emerges 2-3 cm above the ground ( Figure 2 C), the germination rate reached 91.1±0.8%, and the plant height reached 5-8cm in 20 days. Figure 2D). The Corydalis bulbs were harvested on days 12 and 20 for observation and recording, and potted plants were also observed. Results showed that the bulbs grew vigorously ( Figure 2 E and F), shoot length, root length, and root number (Table 1, Figure 2 ).

[0038] The above test results indicate that Corydalis bulbs with a moisture content exceeding 64.8±0.3% should not be stored for more than 10 months.

[0039] Table 1. Effects of Corydalis yanhusuo on bud length, root length, and root number.

[0040]

[0041] Example 3: Screening of moisture content of Corydalis bulbs after long-term storage (58.6±0.7%)

[0042] Using Corydalis bulbs harvested in Pan'an, Zhejiang Province as material, approximately 200 healthy Corydalis bulbs with buds were selected for each treatment. The bulbs with a moisture content of 58.6±0.7% were mixed with dry fine sand, placed in breathable bags, and stored at 25 ℃ and low temperature (3-5 ℃) respectively. After 10 months of storage (April of the following year), all bulbs stored at 25 ℃ became empty and shriveled (as shown in the image). Figure 1 A); Compared with the initial storage period, the morphology of bulbs stored at low temperature did not change significantly (e.g., Figure 3 A). At this point, select some bulbs from the cryopreserved bulbs, place them in moist fine sand, and then put them in a low-temperature environment of 3-5 ℃ for low-temperature imbibition and low-temperature stratification treatment for 20 days. After treatment, the bulbs begin to sprout (e.g., Figure 3 B), the germination rate reached 85.2±1.4%.

[0043] Germinated bulbs were selected for variable-temperature cultivation. The germinated bulbs were sown in a seedling substrate consisting of an imported peat moss:vermiculite:perlite mixture in a volume ratio of 2:1:1. The sowing depth was 2-4 cm in pots with a diameter of 6.5 cm × 6.5 cm. After sowing, the bulbs were thoroughly watered and covered to maintain humidity at 55-65%. Variable-temperature cultivation conditions were: 25℃ during the day, 3000-5000 lx light, and 18℃ at night, in the dark. The results of potted observations are as follows: After 7 days of cultivation, the bulbs began to sprout (…). Figure 3 C); 12 days later, the seedlings emerged 2-3 cm above the ground ( Figure 3 D), the germination rate reached 90.3±1.2%; after 20 days, the plant height reached 3-8cm ( Figure 3 E). The Corydalis bulbs were harvested on days 12 and 20 for observation and recording, while also observing the growth of the potted plants. The results showed that the bulbs grew vigorously ( Figure 3 F and G), shoot length, root length, and root number (Table 2, Figure 3 ).

[0044] The above test results show that Corydalis bulbs with a moisture content of 58.6±0.7% can be stored for a long time, up to 10 months.

[0045] Table 2. Effects of Corydalis yanhusuo on bud length, root length, and root number.

[0046]

[0047] Example 4: Screening of moisture content for long-term storage of Corydalis bulbs (58.6±0.7%, stored for 11 months)

[0048] Using the bulbs from Case 3 that underwent further cryopreservation as material, the remaining bulbs from Case 3, after 10 months of cryopreservation, were further preserved in a low-temperature environment (3-5 ℃) for 11 months (early May of the following year). At this point, the bulbs showed no significant morphological changes compared to the initial preservation period (e.g., ...). Figure 4 A). Select some bulbs and place them in moist fine sand, then put them in a low-temperature environment of 3-5 ℃ for low-temperature imbibition and low-temperature stratification for 20 days. After treatment, the bulbs will begin to sprout (e.g., Figure 4 B), the germination rate reached 84.8±2.1%.

[0049] Germinated bulbs were selected for variable-temperature cultivation. The germinated bulbs were sown in a seedling substrate consisting of an imported peat moss:vermiculite:perlite mixture in a volume ratio of 2:1:1. The sowing depth was 2-4 cm in pots with a diameter of 6.5 cm × 6.5 cm. After sowing, the bulbs were thoroughly watered and covered to maintain humidity at 55-65%. Variable-temperature cultivation conditions were: 25℃ during the day, 3000-5000 lx light, and 18℃ at night, in the dark. The results of potted observations are as follows: After 7 days of cultivation, the bulbs began to sprout (…). Figure 4 C); 12 days later, the seedlings emerged 2-3 cm above the ground ( Figure 4 D), the germination rate reached 88.7±1.9%; after 20 days, the plant height reached 3-8cm ( Figure 4 E). The bulbs were removed on days 12 and 20 for observation and recording, while also observing the growth of the potted plants. The results showed that the bulbs were growing vigorously ( Figure 4 F and G), shoot length, root length, and root number (Table 3, Figure 4 ).

[0050] The above experimental results show that Corydalis bulbs with a moisture content of about 58.6±0.7% can still germinate and grow normally after being stored for 11 months, further demonstrating that Corydalis bulbs can be stored for a long time under this moisture content condition.

[0051] Table 3. Effects of Corydalis yanhusuo on bud length, root length, and root number.

[0052]

[0053] Example 5: Screening of moisture content for long-term storage of Corydalis bulbs (51.6±1.2%)

[0054] Using Corydalis bulbs harvested in Pan'an, Zhejiang Province as material, approximately 100 healthy Corydalis bulbs with buds were selected for each treatment. The bulbs, with a moisture content of 51.6±1.2%, were mixed with dry fine sand, placed in breathable bags, and stored at 25℃ and low-temperature environments (3-5℃), respectively. After 10 months of storage (April of the following year), all bulbs stored at 25℃ became empty and shriveled (as shown in the image). Figure 1 A); Compared with the initial storage period, the morphology of bulbs stored at low temperature did not change significantly (e.g., Figure 5 A). The cryopreserved bulbs were then placed in moist fine sand and kept in a low-temperature environment of 3-5°C for 20 days for low-temperature imbibition and stratification treatment. After treatment, a few mold spots appeared on the surface of the bulbs (e.g., Figure 5 B).

[0055] The above experimental results show that although Corydalis bulbs with a moisture content of about 51.6±1.2% can be preserved for a long time, the bulb activity is difficult to maintain and they cannot germinate normally.

[0056] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for long-term preservation of Corydalis bulbs and maintenance of their activity, characterized in that, include: (1) Selecting Corydalis bulbs; (2) The bulbs selected in step (1) were air-dried to control the moisture content of the bulbs to 58.6 ± 0.7%; (3) Place the bulbs treated in step (2) in a low temperature environment of 3-5℃ for long-term storage; (4) Take out the bulbs that have been stored for more than 10 months in step (3) and perform low-temperature swelling and low-temperature stratification treatment; (5) The bulbs treated in step (4) are subjected to variable temperature cultivation to obtain the seedlings of Corydalis yanhusuo.

2. The method according to claim 1, characterized in that, Step (1) specifically involves selecting healthy, plump, and disease-free Corydalis bulbs.

3. The method according to claim 1, characterized in that, In step (2), the air-drying process is as follows: the Corydalis bulbs are placed in a breathable bag and placed in a ventilated and dry place for natural air drying. The moisture content of the bulbs is measured every day until the moisture content reaches 58.6 ± 0.7%.

4. The method according to claim 1 or 3, characterized in that, In step (2), the moisture content of the air-dried bulbs ranges from 51.6% to 64.8%.

5. The method according to claim 1, characterized in that, In step (3), the low-temperature preservation specifically involves mixing the Corydalis bulbs with dry fine sand and then placing them in a breathable bag, which is then stored in a refrigerated environment at 3-5℃.

6. The method according to claim 1, characterized in that, In step (4), the low-temperature swelling and low-temperature stratification treatment specifically involves placing the bulbs in moist fine sand and treating them in a low-temperature environment of 3-5℃ for 20 days.

7. The method according to claim 1, characterized in that, In step (5), the conditions for variable temperature cultivation are: daytime temperature 23-27℃, light intensity 3000-5000 lx, nighttime temperature 18-22℃, and dark cultivation.

8. The method according to claim 1 or 7, characterized in that, In step (5), the temperature-controlled incubation period is 6-20 days.

9. The method according to claim 1, characterized in that, In step (5), the bulbs are planted in the seedling substrate, which is a mixed substrate of imported peat moss, vermiculite and perlite with a volume ratio of 2:1:1 and a planting depth of 2-4 cm.

10. The method according to claim 9, characterized in that, In step (5), the seeds are sown in a pot with a diameter of 6.5 cm × 6.5 cm. After sowing, the seeds are thoroughly watered and covered to keep the air humidity at 55-65%.

Images