Method for bottle rooting of tissue culture seedlings of albizia odoratissima

Abstract

This invention discloses a method for exogenous rooting of Albizia julibrissin tissue culture seedlings, comprising the following steps: disinfection of explant material, propagation culture of tissue culture seedlings, external insertion of tissue culture seedlings into bottles, and post-insertion management, to obtain exogenously rooted Albizia julibrissin tissue culture seedlings. This method combines rooting and transplanting acclimatization in the rooting stage of tissue culture seedlings, improving the survival rate of tissue culture seedlings and accelerating the propagation process of Albizia julibrissin seedlings.

Description

Technical Field

[0001] This invention belongs to the field of plant propagation technology, specifically relating to a method for exogenous rooting of Albizia julibrissin tissue culture seedlings. Background Technology

[0002] Albizia julibrissin, also known as black privet, fragrant vine, or fragrant beard tree, is an evergreen tree belonging to the genus Albizia in the legume family. It can grow up to 20 meters tall with a diameter at breast height (DBH) of 60 cm. In my country, it is mainly distributed in Hainan, Guangxi, Yunnan, Sichuan, Guizhou, Guangdong, Zhejiang, and Taiwan provinces, and is a precious native tree species of Guangxi. Albizia julibrissin grows rapidly, with a straight trunk, small crown, strong natural regeneration ability, a well-developed root system, abundant nitrogen-fixing nodules, and a high timber yield, making it an excellent and high-value afforestation species. Black privet has excellent wood properties, beautiful appearance, good dimensional stability, and is rot-resistant and insect-resistant, making it a superior material for furniture, construction, shipbuilding, vehicles, carving, and various decorations. It can also be used as a raw material for tannin extraction. It has extremely high medicinal value; the roots are used medicinally to treat symptoms such as rheumatic joint pain, bruises, sores, and insomnia. Its sparse foliage makes it suitable for mixed forests with various tree species, which has a good effect on improving soil, enhancing the forest ecosystem, and increasing the volume per unit area.

[0003] Currently, the main method of propagation for Albizia julibrissin is sexual reproduction through seed orchards and seed collection mother forests. However, sexual reproduction suffers from problems such as genetic differentiation and low propagation efficiency, failing to maximize the improvement gains. Asexual reproduction, on the other hand, can effectively overcome these shortcomings. Furthermore, traditional cutting propagation is difficult to root, has a low seedling rate, and a long cycle, making it impossible to obtain a large number of clonal seedlings in a short period. Grafting and other asexual reproduction techniques are also difficult to meet the needs of large-scale afforestation. Tissue culture is a rapid and effective asexual reproduction method that can effectively expand superior germplasm sources / families and obtain a large number of high-quality Albizia julibrissin seedlings in a short period.

[0004] Existing research and practice show that in-bottle rooting of Albizia julibrissin tissue culture seedlings has problems such as high cost and long cycle. In recent years, in-bottle rooting technology for tissue culture seedlings has been fully practiced and developed. The key to this technology is to combine the rooting and transplanting acclimatization stages of tissue culture seedlings, eliminating the in-bottle rooting procedure and directly transplanting individual Albizia julibrissin tissue culture seedlings from subculture propagation to greenhouses. Compared with the traditional tissue culture seedling production process, the application of this technology not only reduces one aseptic operation step, saves culture room space, reduces the input of raw materials and labor for rooting culture, lowers production costs, and improves production efficiency, but also avoids the adaptation period required for Albizia julibrissin seedlings rooted in bottles to the transplanting greenhouse, thereby shortening the seedling cycle and achieving the goal of simplifying the production process and reducing production costs. The purpose of this invention is to simplify the production process of Albizia julibrissin tissue culture seedlings and, based on publication number (CN112088776A), develop an in-bottle rooting technology that improves the rooting efficiency of Albizia julibrissin tissue culture seedlings, shortens the seedling cycle, and reduces production costs. Summary of the Invention

[0005] This invention simplifies the production process of Albizia julibrissin tissue culture seedlings.

[0006] To achieve the above-mentioned objectives, this invention provides a method for exogenous rooting of Albizia julibrissin tissue culture seedlings, comprising: disinfection of explant material, propagation culture of tissue culture seedlings, external insertion of tissue culture seedlings into bottles, and post-insertion management, to obtain exogenous rooted Albizia julibrissin tissue culture seedlings. The operation steps are as follows:

[0007] (1) Disinfection treatment of explant materials: Select superior single plants, ring cut / cut them to promote sprouting, and collect tender stems with axillary buds or terminal buds as explants on sunny days after sprouting; remove most of the leaves, cut into 3-5 cm stem segments with buds, rinse with sterile water, soak in 75% alcohol for 30 seconds, rinse with sterile water 3-5 times, put them in 2% sodium hypochlorite solution for 10 minutes, rinse clean, disinfect with 0.1% mercuric chloride for 8 minutes, shake the bottle to allow the stem segments to fully contact the disinfectant, rinse with sterile water 6-8 times, and finally dry with sterile absorbent paper.

[0008] (2) Tissue culture seedling proliferation culture: The sterilized materials are subjected to primary induction, subculture proliferation and elongation culture.

[0009] (3) External cutting of tissue culture seedlings: The tissue culture seedlings obtained in step (2) are removed from the culture room and placed in the natural environment for 7 days. Then, the bottle mouth is opened and placed for 1-2 days. Take out the subculture seedlings with a length of 2-6 cm, wash off the culture medium, and insert the stem segments with buds. Before inserting, soak the lower 1-2 cm of the stem segment in 100-150 mg / L ABT rooting solution for 10-15 min. After taking it out, soak it in 100-150 mg / L NAA rooting solution for 10-15 min. Then insert it into the sterilized fine sand substrate at a depth of 1-2 cm.

[0010] (4) Post-cutting management: After cutting, water thoroughly, cover with film to keep warm and moist, and control humidity to 80%-90%; after 2 weeks, remove the film, spray foliar fertilizer once every 10 days, and spray fungicide once every 20 days; after 50-60 days, when the seedlings have developed stable roots, cut open the cutting cup bag and transplant the seedlings into nutrient cups filled with nutrient soil. The nutrient soil raw materials and ratio are yellow soil: coconut coir: sugarcane bagasse: vermiculite = 3:3:2:2; after transplanting, carry out routine seedling management such as watering, fertilization and pest and disease control according to conventional methods.

[0011] Furthermore, in step (1), the ring-cutting / cutting method for promoting bud break involves selecting a location 10-30 cm from the ground at the base of the trunk of a superior Albizia julibrissin tree, cutting into the bark to the xylem with a cutting width of 0.5-1.0 cm, and then spraying with 3% sodium nitrate·naphthaleneacetic acid aqueous solution to break dormancy and promote bud break.

[0012] Furthermore, the explant disinfection method is 75% alcohol for 30 seconds + 2% sodium hypochlorite for 10 minutes + 0.1% mercuric chloride for 8 minutes. After each disinfection step, the explants must be rinsed thoroughly with sterile water.

[0013] Furthermore, in step (3), before performing external cuttings, the tissue culture seedlings are moved out of the culture room and placed in a natural environment for 7 days, and then the bottle opening is opened and placed for 1-2 days.

[0014] Furthermore, the fine sand used as the cutting substrate is disinfected with a 0.5% potassium permanganate solution.

[0015] Furthermore, in step (4), the foliar fertilizer is a leaf pulsation concentrated type and a water-soluble fertilizer containing macro-elements used alternately, and the fungicide is a mixed solution of 200 mg / L chlorothalonil and 250 mg / L thiophanate-methyl.

[0016] The method for exogenous rooting of Albizia julibrissin tissue culture seedlings provided by this invention has the following beneficial effects:

[0017] 1. Compared with conventional tissue culture methods, this invention eliminates the in-bottle rooting step of Albizia julibrissin, avoids the adaptation period required for seedlings rooted in in-bottle to be transplanted to the greenhouse, thereby shortening the seedling cultivation cycle, reducing the input of raw materials and labor for rooting culture, lowering production costs, and improving production efficiency.

[0018] 2. This invention uses exo-rooting, combining the rooting and acclimatization process of Albizia julibrissin, which improves the survival rate of tissue culture seedlings, accelerates the seedling propagation process, and facilitates the industrialized seedling production of Albizia julibrissin.

[0019] 3. This invention provides some reference value for the rooting of other woody plant seedlings produced in industrialized production. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a diagram showing the elongation of adventitious shoots obtained after subculture elongation culture in Example 2;

[0022] Figure 2 This is a diagram of the external cutting transplantation of tissue culture seedlings obtained in Example 2;

[0023] Figure 3 These are the seedlings that survived external rooting obtained in Example 2;

[0024] Figure 4 This is a picture of tissue culture cuttings transplanted 30 days after being obtained in Example 2. Detailed Implementation

[0025] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention. Example

[0026] A method for in vitro rooting of Albizia julibrissin tissue culture seedlings is described below:

[0027] (1) Disinfection treatment of explant materials: Select vigorous, straight, and disease-free single plants from superior seed sources / families. Ring cut / cut them 10 cm from the ground to promote sprouting. Use a tool to cut into the bark to the xylem with a cut width of 0.5 cm. Then spray with 3% sodium nitrate·naphthaleneacetic acid aqueous solution. After sprouting, collect tender stems with axillary or terminal buds as explants on a sunny day. Remove most of the leaves and cut them into 3 cm stem segments with buds. Rinse them with sterile water, soak them in 75% alcohol for 30 seconds, rinse them with sterile water 3 times, put them in 2% sodium hypochlorite solution for 10 minutes, rinse them clean, disinfect them with 0.1% mercuric chloride for 8 minutes, shake the bottle to allow the stem segments to fully contact the disinfectant, rinse them with sterile water 6 times, and finally dry them with sterile absorbent paper.

[0028] (2) Tissue culture seedling proliferation culture: Under aseptic conditions, the sterilized explants were cut off at the wound site and inoculated into induction medium I with 0.0003 parts of 6-BA, 0.0005 parts of NAA, 15 parts of sucrose, 5 parts of agar, and 6 parts of modified MS. The explants were placed in an environment with ordinary fluorescent lamps as the light source, with a light intensity of 1500 Lx and a light duration of 12 h / d. Initial adventitious buds were obtained after about 15 days of culture. The obtained initial buds were inoculated into subculture proliferation medium II prepared with 0.02 parts of riboflavin, 0.01 parts of ascorbic acid, 0.0003 parts of NAA, 0.0003 parts of gibberellic acid, 0.2 parts of hydrolyzed protein, 15 parts of sucrose, 5 parts of agar, and 6 parts of modified MS in a sterile ultra-clean workbench. Subculture buds were obtained after 20 days of culture. The subculture buds were repeatedly subjected to elongation culture to obtain enough subculture buds for exorooting.

[0029] (3) External cutting of tissue culture seedlings: The obtained tissue culture seedlings were removed from the culture room and placed in the natural environment for 7 days, and then the bottle mouth was opened and placed for 1 day; 2 cm long subculture seedlings were taken out, the culture medium was washed off, and the stem segments with buds were inserted; before insertion, the lower 1 cm of the stem segment was soaked in 100 mg / L ABT for 15 min, and then soaked in 100 mg / L NAA for 15 min; then the cuttings were inserted into fine sand substrate disinfected with 0.5% potassium permanganate solution at a depth of 1 cm.

[0030] (4) Post-cutting management: After cutting, water thoroughly, cover with film to keep warm and moist, and control humidity to 80%; after 2 weeks, remove the film, spray foliar fertilizer once every 10 days, and spray fungicide once every 20 days. The foliar fertilizer is a combination of leaf pulsation concentrated type and water-soluble fertilizer with macro elements. The fungicide is a mixed solution of 200 mg / L chlorothalonil and 250 mg / L methyl thiophanate; after 60 days, when the seedlings have developed stable roots, cut open the cutting cup bag and transplant the seedlings into nutrient cups filled with nutrient soil (yellow core soil: coconut coir: sugarcane bagasse: vermiculite = 3:3:2:2). Perform routine seedling management such as watering, fertilization and pest and disease control according to conventional methods. Example

[0031] A method for in vitro rooting of Albizia julibrissin tissue culture seedlings is described below:

[0032] (1) Disinfection treatment of explant materials: Select vigorous, straight, and disease-free single plants from superior seed sources / families. Ring cut / cut them at 20 cm from the ground to promote sprouting. Use a tool to cut into the bark to the xylem with a cut width of 0.8 cm. Then spray with 3% sodium nitrate·naphthaleneacetic acid aqueous solution. After sprouting, collect tender stems with axillary or terminal buds as explants on a sunny day. Remove most of the leaves and cut them into 4 cm stem segments with buds. Rinse them with sterile water, soak them in 75% alcohol for 30 seconds, rinse them with sterile water 4 times, put them in 2% sodium hypochlorite solution for 10 minutes, rinse them clean, disinfect them with 0.1% mercuric chloride for 8 minutes, shake the bottle to allow the stem segments to fully contact the disinfectant, rinse them with sterile water 7 times, and finally dry them with sterile absorbent paper.

[0033] (2) Tissue culture seedling proliferation culture: Under aseptic conditions, the sterilized explants were cut off at the wound site and inoculated into induction medium I with 0.0005 parts of 6-BA, 0.0008 parts of NAA, 20 parts of sucrose, 6 parts of agar, and 5 parts of modified MS. The explants were placed in an environment with ordinary fluorescent lamps as the light source, with a light intensity of 2000 Lx and a light duration of 13 h / d. Initial adventitious shoots were obtained after about 15 days of culture. The obtained initial shoots were inoculated into subculture proliferation medium II, which was prepared by 0.025 parts of riboflavin, 0.015 parts of ascorbic acid, 0.0005 parts of NAA, 0.0004 parts of gibberellic acid, 0.4 parts of hydrolyzed protein, 20 parts of sucrose, 6 parts of agar, and 5 parts of modified MS, in a sterile ultra-clean workbench. Subcultured shoots were obtained after 10 days of culture. The subcultured shoots were repeatedly subjected to elongation culture to obtain enough subcultured shoots for exorooting.

[0034] (3) External cutting of tissue culture seedlings: The obtained tissue culture seedlings were removed from the culture room and placed in the natural environment for 7 days, and then the bottle mouth was opened and placed for 2 days; 4 cm long subculture seedlings were taken out, the culture medium was washed off, and the stem segments with buds were inserted; before insertion, the lower 1.5 cm of the stem segment was soaked in 150 mg / L ABT for 10 min, and then soaked in 100 mg / L NAA for 15 min; then the cuttings were inserted into fine sand substrate disinfected with 0.5% potassium permanganate solution at a depth of 1.5 cm;

[0035] (4) Post-cutting management: After cutting, water thoroughly, cover with film to keep warm and moist, and control humidity at 85%; after 2 weeks, remove the film, spray foliar fertilizer once every 10 days, and spray fungicide once every 20 days. The foliar fertilizer is a combination of leaf pulsation concentrated type and water-soluble fertilizer with macro elements. The fungicide is a mixed solution of 200 mg / L chlorothalonil and 250 mg / L methyl thiophanate; after 50 days, when the seedlings have developed stable roots, cut open the cutting cup bag and transplant the seedlings into nutrient cups filled with nutrient soil (yellow core soil: coconut coir: sugarcane bagasse: vermiculite = 3:3:2:2). Perform routine seedling management such as watering, fertilization and pest and disease control according to conventional methods. Example

[0036] A method for in vitro rooting of Albizia julibrissin tissue culture seedlings is described below:

[0037] (1) Disinfection treatment of explant materials: Select vigorous, straight, and disease-free single plants from superior seed sources / families. Ring cut / cut them at 30 cm from the ground to promote sprouting. Use a tool to cut into the bark to the xylem with a cut width of 1.0 cm. Then spray with 3% sodium nitrate·naphthaleneacetic acid aqueous solution. After sprouting, collect tender stems with axillary or terminal buds as explants on a sunny day. Remove most of the leaves and cut them into 5 cm stem segments with buds. Rinse them with sterile water, soak them in 75% alcohol for 30 seconds, rinse them with sterile water 5 times, put them in 2% sodium hypochlorite solution for 10 minutes, rinse them clean, disinfect them with 0.1% mercuric chloride for 8 minutes, shake the bottle to allow the stem segments to fully contact the disinfectant, rinse them with sterile water 8 times, and finally dry them with sterile absorbent paper.

[0038] (2) Tissue culture seedling proliferation culture: Under aseptic conditions, the sterilized explants were cut off at the wound site and inoculated into induction medium I with 0.0008 parts of 6-BA, 0.0010 parts of NAA, 25 parts of sucrose, 8 parts of agar, and 4 parts of modified MS. The explants were placed in an environment with ordinary fluorescent lamps as the light source, with a light intensity of 2200 Lx and a light duration of 14 h / d. Initial adventitious shoots were obtained after about 15 days of culture. The obtained initial shoots were inoculated into subculture proliferation medium II prepared with 0.03 parts of riboflavin, 0.02 parts of ascorbic acid, 0.0006 parts of NAA, 0.0005 parts of gibberellic acid, 0.6 parts of hydrolyzed protein, 25 parts of sucrose, 8 parts of agar, and 4 parts of modified MS in a sterile ultra-clean workbench. Subcultured shoots were obtained after 15 days of culture. The subcultured shoots were repeatedly subjected to elongation culture to obtain enough subcultured shoots for exorooting.

[0039] (3) External cutting of tissue culture seedlings: The obtained tissue culture seedlings were removed from the culture room and placed in the natural environment for 7 days, and then the bottle mouth was opened and placed for 2 days; 6 cm long subculture seedlings were taken out, the culture medium was washed off, and the stem segments with buds were inserted; before insertion, the lower 2 cm of the stem segment was soaked in 150 mg / L ABT for 10 min, and then soaked in 150 mg / L NAA for 10 min; then the cuttings were inserted into fine sand substrate disinfected with 0.5% potassium permanganate solution at a depth of 2 cm.

[0040] (4) Post-cutting management: After cutting, water thoroughly, cover with film to keep warm and moist, and control humidity to 90%; after 2 weeks, remove the film, spray foliar fertilizer once every 10 days, and spray fungicide once every 20 days. The foliar fertilizer is a combination of leaf pulsation concentrated type and water-soluble fertilizer with macro elements. The fungicide is a mixed solution of 200 mg / L chlorothalonil and 250 mg / L methyl thiophanate; after 60 days, when the seedlings have developed stable roots, cut open the cutting cup bag and transplant the seedlings into nutrient cups filled with nutrient soil (yellow core soil: coconut coir: sugarcane bagasse: vermiculite = 3:3:2:2). Perform routine seedling management such as watering, fertilization and pest and disease control according to conventional methods.

[0041] The application proposes experiments based on different germination-inducing methods, presenting four germination outcomes:

[0042]

[0043] Table 1

[0044] As shown in Table 1, treatments 1, 2, and 3 all yielded a high number of buds, indicating that girdling promoted bud growth effectively. Among these, the best bud growth was achieved when the girdling height was 20 cm above the ground, the cut width was 0.8 cm, and a 3% sodium nitrate·naphthaleneacetic acid aqueous solution was sprayed. Treatment 4, which did not involve hormone spraying, showed poor results.

[0045] The application conducted experiments based on different types and concentrations of rooting solutions, presenting seven rooting solution treatment methods and recording their survival rates after 30 and 60 days, as shown in the table below:

[0046]

[0047] Table 2

[0048] As shown in Table 2, treatments 1, 2, and 3 are the rooting water concentrations of Examples 1, 2, and 3, respectively. Their survival rates after 30 and 60 days are relatively high. The optimal treatment is a mixture of 150 mg / L ABT and 100 mg / L NAA, with survival rates of 91.67% and 88.33% after 30 and 60 days, respectively.

[0049] Compared with treatment 2, under the same other culture conditions, treatment 4, which involved soaking in 250 mg / L ABT rooting solution, resulted in a 12.5% ​​decrease in survival rate after 30 days and a 14.16% decrease in survival rate after 60 days.

[0050] Compared with treatment 2, under the same other culture conditions, treatment 5, which involved soaking in 300 mg / L ABT rooting solution, resulted in a 8.34% decrease in survival rate after 30 days and a 7.5% decrease in survival rate after 60 days.

[0051] Compared with treatment 2, under the same other culture conditions, treatment 6, which involved soaking in a single rooting solution of 250 mg / L NAA, resulted in a 6.67% decrease in survival rate after 30 days and a 6.66% decrease in survival rate after 60 days.

[0052] Compared with treatment 2, under the same other culture conditions, treatment 7, which involved soaking in a single rooting solution of 300 mg / L NAA, resulted in a 11.67% decrease in survival rate after 30 days and a 10.83% decrease in survival rate after 60 days.

[0053] The application was to conduct an experiment based on transplanting nutrient soil from tissue culture cuttings. Ten different transplanting substrates were provided, and the survival rate 30 days after transplanting and the growth status 3 months after transplanting were recorded, as shown in the table below:

[0054]

[0055] Table 3

[0056] As shown in Table 3, Treatment 3 is the optimal transplanting substrate, with a survival rate of 90.00% after 30 days of transplanting. After 3 months, the seedlings exhibit robust stem and leaf growth, reaching a height of 10-12 cm, and new buds have emerged. This substrate is the same as the transplanting substrate used in Examples 1, 2, and 3.

[0057] Compared with treatment 3, under the same other cultivation conditions, the survival rate of treatment 1 was 85.00% 30 days after transplanting, and the seedlings were vigorous with strong stems and leaves after 3 months, with a height of 7-9cm and new buds sprouting. The survival rate was 5.00% lower than that of treatment 3, and the seedling height difference was about 3cm.

[0058] Compared with treatment 3, under the same other cultivation conditions, the survival rate of treatment 2 seedlings 30 days after transplanting was 62.50%, and the seedlings were vigorous with strong stems and leaves after 3 months, with a height of 7-9cm and new buds sprouting. The survival rate of treatment 2 was 27.50% lower than that of treatment 3, and the seedling height difference was about 3cm.

[0059] Compared with treatment 3, under the same other culture conditions, the survival rates of treatments 4, 5 and 6 after transplanting for 30 days were only 7.69%, 35.00% and 22.50% respectively. The transplant survival rate was low, and the plants grew only moderately after 3 months, with seedlings reaching a height of 6-8cm and only a few new buds sprouting.

[0060] Compared with treatment 3, under the same other culture conditions, the survival rates of treatments 7, 8 and 9 after transplanting for 30 days were only 12.50%, 27.03% and 30.00% respectively. The transplant survival rate was low, and the plants grew poorly after 3 months, with seedlings only 6-8cm tall and some leaves falling off.

[0061] Compared with treatment 3, under the same other culture conditions, the survival rate of treatment 10 30 days after transplanting was 84.38%, but the plants grew slowly after 3 months, with seedlings reaching a height of 5-6 cm and no new buds sprouting.

[0062] The above embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Although the invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the invention do not depart from the spirit and scope of the invention and should be covered within the scope of the claims of the invention.

Claims

1. A method for exogenous rooting of Albizia julibrissin tissue culture seedlings, characterized in that, Includes the following steps: (1) Disinfection treatment of explant materials: Select superior single plants and perform girdling / cutting to promote sprouting. Select the base of the trunk of the superior Albizia julibrissin tree 10-30 cm from the ground. Use a tool knife to cut into the bark to the xylem. The cutting width is 0.5-1.0 cm. Then spray 3% sodium nitrate·naphthaleneacetic acid aqueous solution to break dormancy and promote sprouting. After sprouting, collect tender stems with axillary buds or terminal buds on a sunny day as explants. Remove most of the leaves and cut into 3-5 cm stem segments with buds. Rinse with sterile water, soak in 75% alcohol for 30 seconds, rinse with sterile water 3-5 times, put them in 2% sodium hypochlorite solution for 10 minutes, rinse clean, disinfect with 0.1% mercuric chloride for 8 minutes, shake the bottle to allow the stem segments to fully contact the disinfectant, rinse with sterile water 6-8 times, and finally dry with sterile absorbent paper. (2) Tissue culture seedling proliferation culture: The sterilized materials are subjected to primary induction, subculture proliferation and elongation culture; (3) External cutting of tissue culture seedlings: Remove the tissue culture seedlings obtained in step (2) from the culture room and place them in the natural environment for 7 days. Then open the bottle mouth and place them for 1-2 days. Take out the subculture seedlings with a length of 2-6 cm, wash off the culture medium, and insert the stem segments with buds. Before inserting the cuttings, soak the lower 1-2 cm of the stem segments in 100-150 mg / L ABT rooting solution for 10-15 min. After taking them out, soak them in 100-150 mg / L NAA rooting solution for 10-15 min. Then insert them into the sterilized fine sand substrate at a depth of 1-2 cm. (4) Post-cutting management: After cutting, water thoroughly, cover with film to keep warm and moist, and control humidity to 80%-90%; after 2 weeks, remove the film, spray foliar fertilizer once every 10 days, and spray fungicide once every 20 days; after 50-60 days, when the seedlings have developed stable roots, cut open the cutting cup bag and transplant the seedlings into nutrient cups filled with nutrient soil. The nutrient soil raw materials and ratio are yellow soil: coconut coir: sugarcane bagasse: vermiculite = 3:3:2:2; after transplanting, carry out routine seedling management of water, fertilizer and pests and diseases according to conventional methods.

2. The method for exogenous rooting of Albizia julibrissin tissue culture seedlings according to claim 1, characterized in that, In step (3), the fine sand of the cutting substrate is disinfected with a 0.5% potassium permanganate solution.

3. The method for exogenous rooting of Albizia julibrissin tissue culture seedlings according to claim 1, characterized in that, In step (4), the foliar fertilizer is a leaf pulsation concentrated type and a water-soluble fertilizer containing macro-elements used alternately, and the fungicide is a mixed solution of 200 mg / L chlorothalonil and 250 mg / L thiophanate-methyl.

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