A method for rapidly propagating excellent seedlings from the fruit pods of Bletilla ochracea

Abstract

The present invention provides a method for rapidly propagating excellent seedlings from the fruit pods of Bletilla ochracea. The fruit pods of Bletilla ochracea are wiped and sterilized with alcohol and then subjected to a temperature-changing treatment. The seeds after the temperature-changing treatment are inoculated into a starting medium and subjected to light culture until the seeds germinate. The germinated seedlings are inoculated into a protocorm induction and proliferation medium for induction and proliferation culture. The seedlings after the induction and proliferation culture are cultured in a polyploid induction medium. The seedlings after polyploid induction are further cultured on a protocorm-induced bud medium to obtain seedlings. The polyploids obtained by the technical scheme of the present invention can effectively improve the self-crossing ability, thereby increasing the seed setting rate. Thus, a breeding system for rapid propagation of the fruit pods of Bletilla ochracea and selection of excellent varieties with relatively uniform quality is formed.

Description

Technical Field

[0001] The invention discloses a method for rapidly propagating high-quality seedlings from yellow flower Bletilla striata fruit pods, and belongs to the technical field of plant seedling cultivation. Background Art

[0002] Yellow flowered Bletilla: Herbaceous plant, plant height 25-55 cm. Pseudobulb is flat and obliquely ovate, relatively large, with a water chestnut-like ring on the upper surface, rich in stickiness. Stem is relatively sturdy, often with 4 leaves. Leaves are oblong-lanceolate, gradually pointed or acute at the apex, narrowed at the base into a sheath and clasping the stem. Inflorescence has 3-8 flowers, usually unbranched or rarely branched; flowers are medium-sized, yellow or sepals and petals are yellow-green on the outside, yellow-white on the inside, rarely nearly white; sepals and petals are nearly equal in length, oblong, lip elliptical, white or light yellow. Flowering period is June-July. Born in evergreen broad-leaved forests, coniferous forests or under shrubs, in grass or by the ditch at an altitude of 300-2350 meters. Produced in southern Shaanxi, southeastern Gansu, Henan, Hubei, Hunan, Guangxi, Sichuan, Guizhou and Yunnan, China. This flower is cultivated and has high medicinal and horticultural value.

[0003] There are about 30,000 seeds in a normal fruit pod of Bletilla striata, but it is difficult for them to germinate in the natural environment. The traditional technology is to propagate by sowing seeds and cutting bulbs. Not only is the reproduction coefficient low, but as the number of generations increases, the excellent traits of the original variety cannot be maintained. The tissue culture technology of Bletilla striata is becoming more and more mature, but it only grows seeds into protocorms under tissue culture conditions, and then the protocorms are directly sown in the greenhouse seedbed for seedling cultivation. Although tissue culture technology solves the problems of long seed germination time and low germination rate, it fails to solve technical problems such as short production cycle and selection of high-quality varieties with uniform medicinal materials. Summary of the invention

[0004] In view of the above technical problems, the present invention overcomes the shortcomings of the prior art, and rapidly propagates excellent seedlings through the fruit pods of yellow flower white ginseng, which not only solves the technical problems of long germination time and low germination rate of yellow flower white ginseng seeds, but also improves plant varieties by mutation in the original corm culture stage through tissue culture technology, and enriches resources. It provides a new seedling raising method for rapidly breeding excellent varieties of yellow flower white ginseng, and provides a good reference significance for rescuing and protecting unique, rare and endangered plants.

[0005] A method for rapidly propagating high-quality seedlings of Bletilla striata fruit pods, comprising the following steps:

[0006] (1) Seed pretreatment

[0007] Wipe the yellow flower white pods with alcohol to sterilize them and then perform temperature change treatment;

[0008] (2) Start training

[0009] The seeds after temperature-changing treatment are inoculated into the starting medium and cultured under light until the seeds germinate to form protocorms or buds;

[0010] (3)Protocorm induction and proliferation culture

[0011] The seedlings of the germinated buds are inoculated into the protocorm induction and proliferation medium for induction and proliferation culture;

[0012] (4)Polyploid induction culture

[0013] The seedlings after induction and proliferation culture are cultured in the polyploid induction medium;

[0014] (5)Seedling strengthening culture

[0015] The seedlings after polyploid induction are further cultured on the seedling strengthening medium to obtain high-quality seedlings.

[0016] The temperature-changing treatment is carried out at a temperature difference of 20 - 25°C.

[0017] In a preferred embodiment, the Bletilla ochracea fruit pods are placed at -5 to 5°C and then at 20 - 30°C, and then placed at -5 to 5°C again and then at 20 - 30°C, so that the alternating placement time is 1 - 2 months.

[0018] In another preferred embodiment, the Bletilla ochracea fruit pods are placed at -5 to 5°C for 3 - 7 days and then at 20 - 30°C for 3 - 7 days, and then placed at -5 to 5°C for 3 - 7 days and then at 20 - 30°C for 3 - 7 days, so that the alternating placement time is 1 - 2 months.

[0019] In some embodiments, the Bletilla ochracea fruit pods are placed at 4 - 5°C for 7 days and then at 24 - 25°C for 7 days, and then placed at 4 - 5°C for 7 days and then at 24 - 25°C for 7 days, so that the alternating placement time is 2 months.

[0020] The starting medium described in step (2) is MS + NAA 0.3 - 0.5 mg / L + CH 0.1 - 0.2 mg / L + sucrose 20 - 30 g / L + agar 5 - 6 g / L, pH 5.5 - 5.8.

[0021] The protocorm induction and proliferation medium described in step (3) is MS + 6 - BA 1.0 - 1.2 mg / L + NAA 0.3 - 0.5 mg / L + CH 0.1 - 0.2 mg / L + sucrose 20 - 30 g / L + agar 3 - 6 g / L, pH 5.5 - 5.8.

[0022] The polyploid induction medium described in step (4) is MS + 6-BA 1.0 - 1.2 mg / L + NAA 0.3 - 0.5 mg / L + CH 0.1 - 0.2 mg / L + oryzalin 0.01 - 0.03 g / L + sucrose 20 - 30 g / L + agar 3 - 6 g / L, with a pH of 5.5 - 5.8.

[0023] The seedling strengthening medium described in step (5) is MS + 6-BA 1.2 - 1.5 mg / L + NAA 0.3 - 0.5 mg / L + CH 0.1 - 0.2 mg / L + sucrose 20 - 30 g / L + agar 3 - 6 g / L, with a pH of 5.5 - 5.8.

[0024] In this case, the plump and large pods obtained by artificial reciprocal cross-pollination are harvested, and a low-temperature + variable-temperature treatment method is adopted to overcome the problems of long seed germination time and low germination rate of Bletilla ochracea. Bletilla ochracea can start germinating in 3 days, with a germination rate of 89%, a protocorm induction rate of 96.0% or more, and a protocorm multiplication rate of 5.9% or more. When the concentration of oryzalin is 0.03 g / L, the polyploid induction rate of Bletilla ochracea is 58.0% or more, and the polyploid state is the best. The obtained polyploids can effectively improve the self-crossing ability, thereby increasing the seed setting rate. Thus, a rapid propagation system for Bletilla ochracea pods and a breeding system for high-quality and relatively uniform varieties are formed. Description of the Drawings

[0025] Figure 1 For the induction of seed germination of Bletilla ochracea in Example 1.

[0026] Figure 2 For the germinated seedlings of the embryo of Bletilla ochracea in Example 1.

[0027] Figure 3 For the induction of protocorms of Bletilla ochracea in Example 2.

[0028] Figure 4 For the polyploid culture of Bletilla ochracea in Example 3.

[0029] Figure 5 For the seedling strengthening culture of Bletilla ochracea in Example 4. Detailed Description of the Invention

[0030] Example 1

[0031] 1 Seed Collection and Treatment

[0032] 1.1 Seed Selection

[0033] Select the tubers of Bletilla ochracea with strong growth for propagation to obtain the first batch of seedlings. Then, select thick flower buds within 1 - 3 days during the flowering season. After gently dipping the pollen in the flower, transfer it to the selected flower buds for artificial reciprocal cross-pollination to obtain plump and large pods.

[0034] 1.2 Seed collection

[0035] The collection time of the fruit pods of Bletilla ochracea is from late October to early November. Select the fruit pods with light yellow color, fully mature seed embryos and unopened ones.

[0036] 1.3 Seed pretreatment

[0037] The collected fruit pods of Bletilla ochracea are first wiped on the surface with 70 - 75% alcohol for sterilization, and then the following different pretreatment methods are carried out.

[0038] Pretreatment A: Directly placed in a refrigerator at 4 - 5°C for one month;

[0039] Pretreatment B: Directly placed in a refrigerator at 4 - 5°C for two months;

[0040] Pretreatment C: Directly placed in a refrigerator at 4 - 5°C for three months;

[0041] Pretreatment D: First, place the fruit pods of Bletilla ochracea in a refrigerator at 4 - 5°C for 7 days, then place them in an incubator at a temperature of 24 ± 1°C for 7 days, and the alternating temperature treatment lasts for one month;

[0042] Pretreatment E: First, place the fruit pods of Bletilla ochracea in a refrigerator at 4 - 5°C for 7 days, then place them in an incubator at a temperature of 24 ± 1°C for 7 days, and the alternating temperature treatment lasts for two months;

[0043] Pretreatment F: First, place the fruit pods of Bletilla ochracea in a refrigerator at 4 - 5°C for 7 days, then place them in an incubator at a temperature of 24 ± 1°C for 7 days, and the alternating temperature treatment lasts for three months;

[0044] Control CK: No treatment is carried out, and after conventional sterilization treatment, it is inoculated into the culture medium.

[0045] Under the above treatments, start the culture

[0046] 2 Start the culture

[0047] 2.1 Method

[0048] First, cut off the fruit stalks on the fruit pods of Bletilla ochracea, then soak them in a washing powder solution for 5 - 10 minutes, then rinse them with running water for 1 - 2 hours, dry the surface moisture of the fruit pods with filter paper, soak them in 0.1% mercuric chloride on the inoculation table for 30 - 32 minutes, rinse them with sterile water for 5 - 6 times, and finally dry the surface moisture of the fruit pods with sterile filter paper for standby.

[0049] The seeds of 7 groups of Bletilla ochracea Schltr. fruit pods after different pre-treatments were inoculated into Medium No. 1 (pH 5.5 - 5.8). The seeds of one fruit pod were inoculated for each treatment. After inoculation into the medium, they were cultured in the dark for 7 days (in the subsequent culture, unless otherwise stated, they were cultured under light, and the culture conditions were: light intensity 2500 LX, light cycle 12 h / d, temperature 24 ± 1 °C). The germination time was counted at any time according to the seed germination situation. After 2 days, the germination time of Bletilla ochracea Schltr. seeds was continuously counted, and the germination rate of Bletilla ochracea Schltr. seeds was counted after 30 days.

[0050] 2.2 Medium

[0051] No. 1: MS + NAA 0.5 mg / L + CH 0.1 mg / L + sucrose 30 g / L + agar 6 g / L.

[0052] Table 1 Effects of Different Treatments of Bletilla ochracea Schltr. Fruit Pods on Seed Germination

[0053]

[0054] It can be seen from Table 1 that for the fruit pods of Bletilla ochracea Schltr. after pre-treatment E, from the germination time of the seeds and the statistics after 30 days, the germination time of the seeds is related to the pre-treatment method of the fruit pods. The variable temperature treatment helps to break the seed dormancy; the shortest seed germination time is for pre-treatments E and F, which only takes 3 days; the highest seed germination rate is for pre-treatment F, reaching 90%, and there is also the growth of radicles starting. However, for the fruit pods treated with pre-treatment E, it is two months, and for the fruit pods treated with pre-treatment F, it is three months. The effect of pre-treatment E is similar to that of pre-treatment F, but the fruit pod treatment time is one month less, saving the pre-treatment time. This shows that when the fruit pods of Bletilla ochracea Schltr. are placed in a refrigerator at 4 - 5 °C for 7 days, and then placed in an incubator at a temperature of 24 ± 1 °C for 7 days, after two months of alternating variable temperature treatment, it is beneficial to break the dormancy of Bletilla ochracea Schltr. seeds, quickly promote seed germination, and can improve the seed germination rate. The seed germination time only takes 3 days, and the seed germination rate reaches 89%.

[0055] Example 2

[0056] Under the conditions of the above Example 1, protocorm induction and proliferation culture were carried out as follows:

[0057] The materials with different pre-treatments in Example 1 above were used for the following experiments. Specifically: when the seedlings with germinated embryos grew to 1 - 2 cm, the buds were taken out on the ultra-clean workbench, and the seedlings were placed horizontally and transferred to Medium No. 2 (pH 5.5 - 5.8) respectively. They were cultured in the dark for 15 days at a temperature of 24 ± 2 °C and a humidity of 75 ± 2%. Then, the culture bottles after dark culture were transferred to the culture conditions: light intensity 2500 LX, light cycle 12 h / d, temperature 24 ± 1 °C. The induction start time was counted at any time according to the induction of protocorms, and the induction situation of Bletilla ochracea Schltr. protocorms was continuously counted every 5 days. The induction rate of yellow protocorms was counted after 30 days.

[0058] Protocorm-like body induction and proliferation medium:

[0059] No. 2: MS + 6-BA 1.2 mg / L + NAA 0.1 mg / L + CH 0.5 mg / L + sucrose 30 g / L + agar 6 g / L.

[0060] Table 2 Effects of different pretreatments on protocorm-like body induction and proliferation of Bletilla ochracea

[0061]

[0062] As can be seen from Table 2, the pretreatment has an obvious promoting effect on protocorm-like body induction of Bletilla ochracea. The induction rate and proliferation rate of the alternating temperature pretreatment F for three months are the highest, but there is little difference from the pretreatment E. The difference in the induction rate is 0.08% and the difference in the proliferation rate is 0.04%, but the pretreatment time is one month longer. Considering the comprehensive factors, the pretreatment E is selected: first place the capsules of Bletilla ochracea in a refrigerator at 4-5 °C for 7 d, and then place them in an incubator at 24 ± 1 °C for 7 d. The method of alternating temperature treatment for two months has the best effect on protocorm-like body induction of Bletilla ochracea.

[0063] In addition, in this example, the pretreatment E in Example 1 was also treated with different media. Specifically, when the seedlings germinated from the embryos pretreated with E in Example 1 grew to 1-2 cm, the buds were taken out on a super clean workbench, and the seedlings were placed horizontally and transferred to No. 2, No. 3, and No. 4 media (pH 5.5-5.8) respectively. They were cultured in the dark for 15 days at a temperature of 24 ± 2 °C and a humidity of 75 ± 2%. Then, the culture bottles after dark culture were transferred to the culture conditions: light intensity 2500 LX, light cycle 12 h / d, temperature 24 ± 1 °C. According to the protocorm-like body induction, the start time of induction was counted at any time, and the induction of protocorm-like bodies of Bletilla ochracea was continuously counted every 5 days. The induction rate of yellow protocorm-like bodies was counted after 30 d.

[0064] No. 2: MS + 6-BA 1.2 mg / L + NAA 0.1 mg / L + CH 0.5 mg / L + sucrose 30 g / L + agar 6 g / L.

[0065] No. 3: MS + 6-BA 1.2 mg / L + NAA 0.2 mg / L + CH 0.1 mg / L + sucrose 30 g / L + agar 6 g / L.

[0066] No. 4: MS + 6-BA 1.2 mg / L + NAA 0.5 mg / L + CH 0.1 mg / L + sucrose 30 g / L + agar 6 g / L.

[0067] Table 3 Effects of different hormone combinations on protocorm-like body induction and proliferation of Bletilla ochracea

[0068] Processing number Protocorm induction rate % Protocorm proliferation rate % Protocorm status 2 86.56 4.96 Many green lumps, relatively hard, with much callus 3 64.32 3.14 Light yellow granules, with a compact structure and little callus 4 65.78 6.12 Light green granules, relatively loose

[0069] It can be concluded from Table 3 that the induction level of protocorms of Formula 2 is significantly higher than that of Formulas 3 and 4, indicating that the greater the multiple of cytokinin 6-BA to auxin NAA, the better the induction effect on protocorms; however, in terms of protocorm proliferation, Formula 4 is superior to Formulas 2 and 3. In terms of the state of the induced protocorms, the effect of Formula 3 is the best.

[0070] Example 3

[0071] Under the conditions of the above Example 2, polyploid induction culture was carried out as follows:

[0072] The protocorm clusters induced by the 3rd medium in Example 2 above were used for the following experiments. Specifically: Select the light green granular protocorms in the 3rd medium and transfer them to the 5th, 6th, and 7th media (pH 5.5 - 5.8) respectively. The culture conditions are: light intensity 2000 - 3000 LX, light cycle 12 h / d, temperature 24 ± 1°C. Recording started after 7 days, and the induction of protocorms of Bletilla ochracea was continuously counted every 5 days. After 30 days, transfer them to the strong seedling medium in time, and count the survival rate and polyploid induction rate.

[0073] Medium:

[0074] 5th: MS + 6-BA 1.2 mg / L + NAA 0.5 mg / L + CH 0.1 mg / L + oryzalin 0.01 g / L + sucrose 30 g / L + agar 6 g / L.

[0075] 6th: MS + 6-BA 1.2 mg / L + NAA 0.5 mg / L + CH 0.1 mg / L + oryzalin 0.03 g / L + sucrose 30 g / L + agar 6 g / L.

[0076] 7th: MS + 6-BA 1.2 mg / L + NAA 0.5 mg / L + CH 0.1 mg / L + oryzalin 0.05 g / L + sucrose 30 g / L + agar 6 g / L.

[0077] Table 4 Effect of oryzalin concentration on polyploid induction of Bletilla ochracea

[0078]

[0079] Analysis from Table 4 shows that the concentration of oryzalin has an impact on the survival rate of protocorms and the polyploid induction rate of Bletilla ochracea Schltr. When the concentration of oryzalin is 0.01 g / L, the survival rate of protocorms is the best, reaching 87.5%. The survival rate of protocorms is negatively correlated with the concentration of oryzalin, indicating that the higher the concentration of oryzalin, the greater the toxicity to the protocorms of Bletilla ochracea Schltr. When the concentration of oryzalin is 0.05 g / L, the polyploid induction rate is relatively high, reaching 60.5%, indicating that the higher the concentration of oryzalin, the higher the polyploid induction rate of Bletilla ochracea Schltr., but the induced seedlings are deformed and weak. Considering all factors, selecting Formula No. 6 has the best effect on polyploid induction of Bletilla ochracea Schltr.

[0080] Example 4

[0081] Under the conditions of the above Example 3, polyploid seedling strengthening culture was carried out as follows:

[0082] The polyploid seedlings induced by Medium No. 6 in Example 3 above were used for the following experiments. Specifically: The polyploid seedlings induced in Medium No. 6 were selected and cut into clusters of 5 - 8 plants each, and transferred to Medium No. 8 (pH 5.5 - 5.8) for seedling strengthening culture. The culture conditions were: light intensity 2000 - 3000 LX, light cycle 12 h / d, temperature 24 ± 1 °C.

[0083] Medium:

[0084] No. 8: MS + 6 - BA 1.0 mg / L + NAA 0.5 mg / L + CH 0.1 mg / L + sucrose 30 g / L + agar 6 g / L.

[0085] Hardening off and transplanting

[0086] Select the bottle seedlings cultured in Medium No. 8 with a height of more than 3 cm, 4 - 7 leaves, normal leaf color, and having 3 - 5 roots more than 2 cm long. Place them in the greenhouse for 2 - 3 weeks for transitional hardening off to enhance the adaptability of the seedlings to the environment. One to two days before taking out the seedlings from the bottle, open the bottle caps of the seedlings to be taken out to allow the bottle seedlings to gradually adapt to the external light and temperature, and pay attention to controlling the light intensity. When the sunlight intensity is greater than 8000 lx, shade treatment is required.

[0087] Substrate preparation

[0088] Using perlite 3: expanded vermiculite 3: coconut coir 1: cinder 1: loess 2 as the substrate, the prepared substrate was sterilized in advance for standby.

[0089] Plug tray acclimatization

[0090] Carefully take out the seedlings from the bottle with forceps. First, clean the culture medium on the roots and then wash the roots with clean water. When taking out the seedlings from the bottle, the root epidermis is grayish-white or light green, and there is no black root to avoid root rot caused by mildew of the remaining culture medium. Classify the large and small seedlings and transplant them after the surface moisture of the roots dries and turns white. When transplanting, use the bulb as a unit, with a row spacing of 4-6 cm. When planting in the plug tray, disperse the roots and bury them shallowly in the substrate. The base above the bulb must be exposed and should not be planted too deep, otherwise the base stems and leaves are prone to soft rot.

[0091] After the tissue-cultured seedlings are planted in the plug tray, pour a small amount of fixing water to fix the roots, place them in a shaded place, keep the air humidity at 80%-90%, ventilate properly, and maintain the temperature at 20-25°C. Spray fungicide water every 2-3 days until the new leaves of the transplanted small seedlings unfold and the roots of the seedlings elongate. Then, spray and top-dress with a 1000-fold dilution of MS macroelements every month. After the small seedlings survive, transplant them into flower pots.

[0092] Example 5

[0093] Sow the fruit pods obtained in the seed selection of Example 1 above under natural conditions. The method is as follows: Soak the Bletilla striata fruit pods in a greenhouse for 24 hours for germination, and sow them on a substrate of perlite:vermiculite:coconut coir:charcoal slag:loess = 3:3:1:1:2. The management conditions are: temperature 20°C, humidity 90%, light intensity 2000-3000 LX, until emergence.

[0094] Compare the traits of the seedlings induced under the conditions of Example 4 above with those of the naturally sown seedlings at each stage as follows:

[0095] Table 5 Traits of sown seedlings and protocorm-induced seedlings at each stage

[0096]

[0097] As can be seen from Table 5, the growth status indicators of the sown seedlings and protocorm-induced seedlings of Bletilla ochracea all show an upward trend with the growth months. The growth of the protocorm-induced seedlings of Bletilla ochracea with the same seedling age is higher than that of the sown seedlings. It shows that the protocorm-induced seedlings of Bletilla ochracea have the advantages of fast growth rate and short production cycle compared with the seedling; and the seedlings induced by protocorms have relatively single heredity, consistent seedling stage, consistent quality, relatively neat medicinal material quality, can quickly select better varieties, and are conducive to popularization and application.

Claims

1. A method for propagating seedlings from the fruit pods of Bletilla ochracea, which is characterized in that, it comprises the following steps: (1) Seed pretreatment Wipe the fruit pods of Bletilla ochracea with alcohol for sterilization and then perform temperature variation treatment. Place the fruit pods of Bletilla ochracea at -5 to 5 °C and then at 20 - 30 °C, and then place them at -5 to 5 °C again and then at 20 - 30 °C. In this way, the alternating placement time is 1 - 2 months; (2) Initiation culture Inoculate the seeds after temperature variation treatment into the initiation medium and perform light culture until the seeds germinate. The initiation medium is MS + NAA 0.3 - 0.5 mg / L + CH 0.1 - 0.2 mg / L + sucrose 20 - 30 g / L + agar 5 - 6 g / L, pH 5.5 - 5.8; (3) Protocorm induction and proliferation culture Inoculate the germinated seedlings into the protocorm induction and proliferation medium for induction and proliferation culture. The protocorm induction and proliferation medium is MS + 6 - BA 1.0 - 1.2 mg / L + NAA 0.3 - 0.5 mg / L + CH 0.1 - 0.2 mg / L + sucrose 20 - 30 g / L + agar 3 - 6 g / L, pH 5.5 - 5.8; (4) Polyploid induction culture Culture the seedlings after induction and proliferation culture in the polyploid induction medium. The polyploid induction medium is MS + 6 - BA 1.0 - 1.2 mg / L + NAA 0.3 - 0.5 mg / L + CH 0.1 - 0.2 mg / L + oryzalin 0.01 - 0.03 g / L + sucrose 20 - 30 g / L + agar 3 - 6 g / L, pH 5.5 - 5.8; (5) Seedling strengthening culture Culture the seedlings after polyploid induction on the seedling strengthening medium to obtain seedlings. The seedling strengthening medium is MS + 6 - BA 1.2 - 1.5 mg / L + NAA 0.3 - 0.5 mg / L + CH 0.1 - 0.2 mg / L + sucrose 20 - 30 g / L + agar 3 - 6 g / L, pH 5.5 - 5.

8.

2. The method for propagating seedlings from the fruit pods of Bletilla ochracea according to claim 1, which is characterized in that, place the fruit pods of Bletilla ochracea at -5 to 5 °C for 3 - 7 days and then at 20 - 30 °C for 3 - 7 days, and then place them at -5 to 5 °C again for 3 - 7 days and then at 20 - 30 °C for 3 - 7 days. In this way, the alternating placement time is 1 - 2 months.

3. The method for propagating seedlings from the fruit pods of Bletilla ochracea according to claim 2, which is characterized in that, place the fruit pods of Bletilla ochracea at 4 - 5 °C for 7 days and then at 24 - 25 °C for 7 days, and then place them at 4 - 5 °C again for 7 days and then at 24 - 25 °C for 7 days. In this way, the alternating placement time is 2 months.

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