Tea tree grafting seedling raising method for shortening breeding period and improving stress resistance

Abstract

This invention relates to the field of tea tree grafting and seedling cultivation technology, and discloses a method for shortening the propagation period and improving the stress resistance of tea tree grafting and seedling cultivation. This method uses seedlings of highly resistant tea tree varieties with cotyledonous seeds as rootstock and non-lignified hard-stemmed tea tree branches as scions. Hormone treatment is applied to the cut surfaces of the scions, which can shorten the seedling cultivation cycle of grafted tea seedlings to 3 months, achieve a survival rate as high as 96.7%, and a transplant survival rate as high as 99.4%. This invention helps to solve the shortcomings of existing short-cutting tea seedlings, such as slow rooting, long seedling cultivation cycle, long transplant recovery period and low survival rate, and poor tea tree resistance, as well as the problems of grafted tea seedlings, such as cumbersome procedures, slow growth and development, easy root damage during seedling lifting, and long transplant recovery period. It significantly shortens the tea seedling propagation cycle and enhances the stress resistance of tea seedlings through grafting, and has the potential for industrial-scale application.

Description

Technical Field

[0001] This invention relates to the field of tea tree grafting and seedling cultivation technology, and in particular to a method for tea tree grafting and seedling cultivation that shortens the propagation period and improves stress resistance. Background Technology

[0002] Short-cutting propagation of tea seedlings is currently the most important method for tea variety propagation in my country. However, whether it is open-field cutting or greenhouse substrate cutting, there are problems such as slow rooting of cuttings, long seedling cultivation period, long recovery period after transplanting, and low survival rate after transplanting. Furthermore, the root system of short-cutting tea seedlings is fibrous, often distributed in a relatively shallow soil layer, which also results in poor stress resistance and high requirements for soil and fertilizer management.

[0003] Grafting technology, by combining the superior traits of the scion variety with the advantageous characteristics of the root system, thereby enhancing the scion variety's resistance and adaptability, is widely used in the propagation and cultivation of trees, fruit trees, and flowers. For tea trees, grafting is mainly used for the replanting and replacement of low-yield, inefficient old tea gardens. However, its application in actual production is limited due to drawbacks such as high labor costs during grafting, tedious post-grafting sprout removal, difficulty in ensuring varietal purity, and a limited period of high yield after the garden is established. In comparison, research on the application of grafting technology in tea variety propagation is even scarcer. Xu Yiding et al. (Patent No.: ZL201210048726.3) reported a grafting method using the embryonic root of seedling tea as rootstock, but this method suffers from problems such as tedious grafting procedures, slow seedling growth and development, easy root damage during seedling lifting, and a long recovery period after transplanting, thus limiting its application in actual production. Li Yeyun et al. (Patent No.: ZL202111423217.X) reported a grafting method for asexual tea seedlings as rootstocks. However, because the root system of the rootstock tea seedlings is a fibrous root system, its resistance to adverse conditions is limited, thus restricting its promotion and application in actual production.

[0004] In view of the shortcomings of the above-mentioned tea seedling grafting and propagation technology, the inventor of this invention has finally obtained this invention after long-term systematic research and production practice, which provides a new technology for the rapid propagation and promotion of asexual superior tea seedlings. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing tea seedling short-cutting propagation techniques, such as slow rooting of cuttings, long seedling cultivation cycle, long recovery period after transplanting, low transplant survival rate, poor tea tree resistance, and high requirements for soil and fertilizer management, as well as the problems of tea seedling grafting propagation techniques, such as cumbersome grafting procedures, slow growth and development of tea seedlings, easy damage to the root system during seedling lifting, and long recovery period after transplanting. This invention provides a grafting seedling propagation method that shortens the propagation cycle and improves the resistance of tea trees.

[0006] The above-mentioned technical objective of this invention is achieved through the following technical solution: a method for grafting tea seedlings to shorten the propagation period and improve stress resistance, comprising the following steps:

[0007] Step 1: Select mature, plump, disease-free, and highly resistant tea tree varieties with high seed setting rate after peeling. Sow the tea seeds in a container and germinate them to obtain tea seedling rootstock.

[0008] Step 2: Select healthy, disease-free, and plump, non-lignified hard-stemmed tea tree branches that have recently grown as scions, and graft them immediately after harvesting.

[0009] Step 3: Select a seedling container based on the characteristics of tea seed root growth and development;

[0010] Step 4: Prepare the grafting seedling substrate. Fill the seedling container with the grafting seedling substrate, water it to make it fully moist, and set it aside.

[0011] Step 5: Cut off the hypocotyl at the upper end of the cotyledon of the tea seedling rootstock from Step 1, and vertically split it in the middle of the hypocotyl cross section to serve as the grafting interface for the rootstock, while retaining the cotyledon of the tea seedling rootstock.

[0012] Step 6: Select scions that meet the requirements of Step 2. Use a single-edged knife to cut a wedge-shaped double bevel at the lower end of the axillary bud, so that the double bevels meet at the pith. Soak the wedge-shaped double bevel in naphthaleneacetic acid solution. Then cut it off at the upper end of the axillary bud to form a scion that meets the requirements of Step 2. Place the prepared scion in a cool place and cover it with a damp gauze or towel to keep it moist until it is ready for use.

[0013] Step 7: Insert the scion from Step 6 into the grafting point of the rootstock from Step 5, and tie the grafting point with plastic film. After tying, place the grafted tea seedling in a shady place and cover it with a damp gauze or towel to keep it moist until it is transplanted.

[0014] Step 8: Plant the grafted tea seedlings from Step 7 into the seedling container from Step 4. The planting depth should be such that the grafting interface is exposed and the cotyledons of the seedling are just buried in the substrate.

[0015] Step 9: Reasonably control the relative humidity of the air and the relative moisture content of the substrate in the greenhouse, and promptly remove the suckers sprouting from the rootstock;

[0016] Step 10: Take out the grafted tea seedlings along with the seedling substrate and plant them.

[0017] The invention is further configured such that, before step one, there is a seed harvesting and storage step. Specifically, mature, plump tea fruits free from pests and diseases are collected, and spread out in a cool, ventilated, and dry place. The spread-out thickness is 3cm to 5cm. The fruits are turned over once or twice a day until the tea seeds are separated from the fruit peel. Then, the tea seeds are soaked in clean water for 2 to 3 days. The high-quality tea seeds that sink to the bottom are selected and stored at low temperature at 5°C and 60% relative humidity.

[0018] A further provision of the present invention is that, in step one, tea seedlings with a bud length of more than 6 cm, a stem diameter of 0.2 cm to 0.4 cm and which have not undergone lignification are selected as rootstocks for tea tree grafting and seedling cultivation.

[0019] A further feature of the present invention is that, in step three, the seedling container is a nutrient pot or non-woven bag with a height of 15cm to 20cm and a diameter of 8cm to 10cm.

[0020] A further provision of the present invention is that, in step four, the grafting seedling substrate is prepared by mixing slightly acidic peat moss and loess in a 1:1 (V:V) ratio.

[0021] A further feature of the present invention is that, in step five, the hypocotyl is cut off 3.0cm to 4.0cm above the cotyledon of the tea seedling, and the grafting depth of the rootstock is 1.5cm.

[0022] A further provision of the present invention is as follows: In step six, a wedge-shaped double bevel with a length of 1.0cm to 1.3cm is cut on both sides at a position 2.0cm to 2.5cm below the axillary bud of the scion. The wedge-shaped double bevel is then soaked in a naphthaleneacetic acid solution with a concentration of 100mg / kg for 1 hour, and then cut off at a position 0.3cm to 0.5cm above the axillary bud to form a scion.

[0023] A further provision of the present invention is that in step nine, when the new shoots of the grafted tea seedlings grow to a height exceeding 30cm, the first shaping pruning is performed 20cm above the grafting point.

[0024] A further feature of the present invention is as follows: In step six, a special cutting tool for cutting a wedge-shaped double-beveled ear is applied. The special cutting tool includes a base. One side of the base is provided with a limiting straight groove for placing the ear. Two oblique cutting blades are correspondingly arranged in a figure-eight shape on both sides of the limiting straight groove. The two oblique cutting blades are slidably placed in the oblique through slots on both sides of the limiting straight groove. A rack is provided on the opposite side of the two oblique cutting blades. The rack is located at the bottom of the straight groove on the surface of the oblique cutting blade. In the base, each oblique cutting blade is provided with a corresponding long rotating shaft. The rack on each oblique cutting blade meshes with the front gear of the corresponding long rotating shaft. The rear gears of the two long rotating shafts mesh with each other. The rear gear is located behind the limiting straight groove.

[0025] A further feature of the present invention is that: two short rotating shafts parallel to the long rotating shafts are provided between the two long rotating shafts, and each of the two short rotating shafts is provided with a transition gear that meshes with the nearest rear gear. A push rod is provided between the two transition gears, and racks that mesh with the transition gears on the two short rotating shafts are provided on both sides of the push rod. The push rod is slidably placed in the through hole of the base, and the through hole is parallel to the limiting straight groove.

[0026] The beneficial effects of this invention are:

[0027] 1. This invention selects seedlings of superior tea varieties with strong resistance and high fruit set rate as grafting rootstocks, making full use of the integrity of their root system and the large amount of nutrients stored in their cotyledons, so that the seedlings can grow rapidly without fertilization during the seedling stage, and can be transplanted 3 months after grafting, which significantly shortens the propagation cycle of asexual tea seedlings.

[0028] 2. This invention uses seedlings grown from seed as grafting rootstock and nutrient pots or non-woven bags as seedling containers. It makes full use of the characteristics of rootstock taproots, such as deep root penetration and strong adaptability, and container seedlings, such as transplanting without damage to the entire root system, transplanting without seasonal restrictions, and no recovery period after transplanting. This results in a grafted seedling survival rate of nearly 100%, shortens the orchard establishment period by 1 to 2 years, and significantly enhances the stress resistance of clonal grafted tea seedlings.

[0029] 3. The process steps and operation methods of this invention are relatively simple. The survival rate of grafted tea seedlings is as high as 96.7% and the nursery rate is as high as 93.1%, which has the prospect of industrial-scale promotion and application.

[0030] 4. This invention not only facilitates the rapid propagation of rare and superior tea tree resources (materials), and helps the process of tea scientific research and new variety breeding; it also facilitates the rapid and widespread application of newly bred superior tea tree varieties, and helps the high-quality development of the tea industry. Attached Figure Description

[0031] Figure 1 A schematic diagram showing the growth state of the rootstock selected for grafting;

[0032] Figure 2 A schematic diagram showing the growth state of the selected scion for grafting;

[0033] Figure 3 This is a schematic diagram showing the grafted tea seedlings after being transplanted into a seedling container.

[0034] Figure 4 This is a diagram showing the growth status of tea seedlings two months after grafting.

[0035] Figure 5 A comparison of the new shoot and root growth status of 2-month-old grafted tea seedlings (right), 1-year-old field cuttings (left), and 1-year-old greenhouse substrate cuttings (middle);

[0036] Figure 6 This is a diagram showing the growth status of the new shoots and roots of the tea seedlings three months after grafting.

[0037] Figure 7 A comparison of the growth status of grafted tea seedlings (left) and cutting tea seedlings (right) in a tea garden 6 months after transplanting;

[0038] Figure 8 This is a schematic diagram of the external structure of the special cutting tool used in this invention;

[0039] Figure 9 This is a schematic diagram of the internal structure of the front side of the special cutting tool used in this invention;

[0040] Figure 10 yes Figure 9 Enlarged view of point A in the middle;

[0041] Figure 11 This is a top view of the drive structure of the internal oblique cutting blade of the special cutting tool used in this invention. Detailed Implementation

[0042] Example 1

[0043] Using branches of the superior tea variety 'Echa No. 1' as scions and seedlings of the highly resistant and high-fruit-setting tea variety 'Echa No. 1' as rootstock, the specific grafting and seedling cultivation steps are as follows:

[0044] (1) Seed Harvesting and Storage: In October, harvest mature, plump tea fruits of the 'Echa No. 1' tea variety, free from pests and diseases. Spread them out in a cool, ventilated, and dry place, with a layer thickness of 3-5 cm. Turn them over once or twice a day until the seeds separate from the fruit peel. Soak the tea seeds in clean water for 2-3 days. Select the high-quality tea seeds that sink to the bottom and store them at a low temperature of 5℃ and a relative humidity of 60%. Low-temperature storage of tea seeds is beneficial for obtaining grafting rootstocks throughout the year, and the grafting time can be flexibly arranged according to specific circumstances.

[0045] (2) Seedling rootstock cultivation: Based on actual grafting needs, evenly sow the cracked tea seeds in a container with a 10cm layer of fine sand at the bottom. Cover the surface with another 3cm layer of fine sand and water thoroughly. Then place the container in an artificial climate chamber with a temperature of 30℃ and a relative humidity of 90% for seed germination. Select seeds with a plumule length of over 6cm, a stem diameter of 0.2cm–0.4cm, and that have not yet lignified (details as follows). Figure 1 The tea seedlings shown are used as rootstocks for grafting and propagating tea trees.

[0046] (3) Selection of grafting scions: Select healthy, disease-free, and non-lignified hard-stemmed tea tree branches with plump axillary buds that have recently grown as scions (details are as follows). Figure 2 (As shown), and should be received immediately upon collection.

[0047] (4) Selection of seedling containers: Based on the characteristics of tea seed root growth and development, thickened nutrient pots or non-woven bags with a height of 15cm and a diameter of 8cm are selected as seedling containers.

[0048] (5) Preparation of seedling substrate: Select slightly acidic peat moss and loess with good air permeability, water retention and fertility, and mix them in a 1:1 (V:V) ratio as the grafting seedling substrate. Fill the seedling container with the mixed substrate to 1 / 2 full, water it to make it fully moist, and then prepare it for use.

[0049] (6) Cutting and splitting the rootstock: Using a knife, cut the hypocotyl 3.0cm to 4.0cm above the cotyledons of the tea seedling that meets the requirements described in step (2). Then, use a double-edged thin blade to vertically split the hypocotyl cross-section in the middle to serve as the grafting interface for the rootstock. The split depth is 1.5cm. The cotyledons of the tea seedling rootstock are retained, which can provide nutrients for the growth and development of the root system of the grafted tea seedling and the new shoots of the scion, and can also promote the rapid healing of the grafting interface, thereby shortening the seedling cultivation period of the grafted tea seedling and improving the survival rate of the grafted tea seedling.

[0050] (7) Cutting and trimming the scion: Select a scion that meets the requirements described in step (3). On both sides of the axillary bud, 2.0cm to 2.5cm below the scion, use a single-edged knife to cut a 1.0cm to 1.3cm long wedge-shaped double bevel, so that the double bevels meet at the pith. Soak the scion in a 100mg / kg naphthaleneacetic acid solution for 1 hour before grafting. Then cut the scion 0.3cm to 0.5cm above the axillary bud to form a scion with a plump axillary bud and a healthy leaf. The prepared grafting scion should be placed in a cool place and covered with a damp gauze or towel to keep it moist until use.

[0051] (8) Inserting the scion and binding: Insert the scion as required in step (7) into the cleft of the rootstock as required in step (6), aligning the cambium layer of the scion with that of the rootstock and ensuring they are tightly fitted. Bind the graft union with a 1.5cm wide plastic film strip to seal it tightly and prevent moisture loss, which could affect the grafting survival rate. After binding, place the grafted tea seedlings in a cool, shady place and cover them with a damp gauze or towel to maintain moisture until transplanting.

[0052] (9) Transplanting grafted tea seedlings: Plant two grafted tea seedlings completed in step (8) in each seedling container as required in step (4), ensuring that the leaves do not overlap (see details). Figure 3(As shown). The planting depth should be such that the grafting point is exposed and the cotyledons of the seedling are just buried in the substrate. Ensure the seedlings are planted firmly, compacted, and without any drooping roots, allowing the roots to be in close contact with the substrate. The substrate should be filled to 90% of the seedling container. Water thoroughly immediately after planting. After the leaves have dried slightly, spray the leaves with 70% thiophanate-methyl or 50% carbendazim for disinfection. Then move the seedlings to the nursery for sealing and moisture retention. Plant two grafted tea seedlings in each seedling container, mainly based on the common planting specifications for newly established tea gardens in my country. Alternatively, one or three or more grafted tea seedlings can be planted depending on specific needs.

[0053] (10) Post-grafting management: Before the graft union heals, the relative humidity of the air in the greenhouse should be controlled at around 90%, and the relative moisture content of the substrate should be maintained at around 80%. After the graft union heals, the moisturizing film should be removed in time while the shade net remains. The relative moisture content of the substrate should be controlled at around 60%, and a longitudinal cut should be made on the film binding tape with a blade to remove the binding tape. Suckers sprouting from the rootstock should be removed in time to reduce the water and nutrient consumption of the grafted seedlings and ensure their rapid growth. When the new shoots of the grafted tea seedlings grow to a height of more than 30cm, the first shaping pruning should be carried out 20cm above the graft union so that the newly established tea garden can close up and form a garden as soon as possible, and generate economic benefits as early as possible.

[0054] (11) Transplanting of grafted tea seedlings: When transplanting tea seedlings, make a longitudinal cut on the seedling container with a blade, remove the grafted tea seedling along with the seedling substrate, and plant it according to the specifications of a newly established tea garden. The planting depth of the tea seedlings should be just above the seedling substrate. The grafted container tea seedlings in this invention not only have the advantages of not damaging the root system during the transplanting process and not being restricted by the season, but also have the advantages of no recovery period after transplanting and simple management, high survival rate and fast garden establishment. At the same time, they also have the characteristics of strong resistance and strong adaptability.

[0055] Three months after grafting (details as follows) Figure 6 As shown in the figure, a statistical analysis was conducted on the survival rate, nursery rate, and new shoot length of grafted tea seedlings. The grafting survival rate was as high as 96.7%, the nursery rate was as high as 93.1%, and the average new shoot length was 25.7 cm.

[0056] Six months after transplanting (details as follows) Figure 7 As shown in the figure, a statistical analysis was conducted on the survival rate, orchard establishment rate, and tree width of the transplanted tea seedlings. The survival rate was as high as 99.4%, the orchard establishment rate was 100%, and the average tree width was 59.8 cm.

[0057] Comparative Example 1

[0058] Compared with Example 1, seedlings grown from seeds with cotyledons removed were selected as grafting rootstocks, and all other implementation steps were the same as those described in Example 1. Three months after grafting, the survival rate of grafted seedlings was 94.3%, the nursery stock rate was 81.2%, and the average length of new shoots was 15.6 cm. This indicates that cotyledons have a significant impact on the growth and development of new shoots in grafted tea seedlings.

[0059] Comparative Example 2

[0060] Compared with Example 1, tea seedlings with semi-lignified and lignified plumules were selected as grafting rootstocks, respectively, and all other implementation steps were the same as those described in Example 1. Three months after grafting, the survival rate of grafted seedlings using tea seedlings with semi-lignified plumules as rootstocks was 79.2%, the nursery stock rate was 68.4%, and the average new shoot length was 18.3 cm. In contrast, the survival rate of grafted seedlings using tea seedlings with lignified plumules as rootstocks was only 46.1%, the nursery stock rate was 28.7%, and the average new shoot length was 8.4 cm.

[0061] Comparative Example 3

[0062] Compared with Example 1, semi-lignified and lignified tea tree branches were selected as scions for grafting, respectively, and all other implementation steps were the same as those described in Example 1. Three months after grafting, the survival rate of grafted seedlings using semi-lignified tea tree branches as scions was 89.0%, the nursery stock rate was 84.1%, and the average new shoot length was 23.2 cm, while the survival rate of grafted seedlings using lignified tea tree branches as scions was 80.5%, the nursery stock rate was 74.2%, and the average new shoot length was 19.0 cm.

[0063] Comparative Example 4

[0064] Compared with Example 1, grafting was performed by cutting and shaping the rootstock and splitting and cutting the scion. All other implementation steps were the same as those in Example 1. The specific steps for cutting and shaping the rootstock are as follows: cut the hypocotyl 3.5cm to 4.0cm above the cotyledon of the tea seedling that meets the requirements of step (2) with a knife, and then use a single-edged knife to cut a wedge-shaped double bevel 1.0cm to 1.3cm long at the uppermost end of the hypocotyl, and meet it at the center of the hypocotyl. The specific steps for splitting and cutting the scion are as follows: select a scion that meets the requirements of step (3), cut it 3.0cm to 3.5cm below the axillary bud and 0.3cm to 0.5cm above the axillary bud, and then use a double-edged thin blade to vertically split the lower end of the cut surface as the grafting interface. The split depth is 1.5cm, forming a scion with a plump axillary bud and a strong leaf. Then, insert the prepared rootstock into the cleft of the scion, aligning the cambium layers of the scion and rootstock, and ensuring close contact. Three months after grafting, the survival rate of grafted seedlings was 47.9%, the nursery stock rate was 23.6%, and the average length of new shoots was 7.5 cm.

[0065] Comparative Example 5

[0066] Compared with Example 1, the cut scion wedge-shaped double bevel was not treated with naphthaleneacetic acid solution soaking, and all other implementation steps were the same as those described in Example 1. The average healing time of the graft union between the rootstock and scion was 28.3 days, which was 14.7 days later than in Example 1; 3 months after grafting, the survival rate of grafted tea seedlings was 85.3%, the nursery stock rate was 76.4%, and the average length of new shoots was 19.0 cm.

[0067] Comparative Example 6

[0068] Compared to Example 1, tea seedlings propagated using the most common tea seedling propagation method in my country (short cutting) were used to establish new tea gardens. All other implementation steps were the same as those described in Example 1. Six months after transplanting (details as follows...), Figure 7 As shown in the figure, a statistical analysis was conducted on the survival rate and tree width of transplanted tea seedlings. The survival rate of transplanted tea seedlings propagated by short cuttings was 81.6%, and the average tree width was 27.7 cm, both of which were significantly lower than the survival rate and tree width of newly established tea gardens using grafted tea seedlings of this invention.

[0069] Example 2

[0070] Using short-cutting seedlings of the superior tea variety 'Echa No. 1' as a control, the cold and drought resistance of grafted tea seedlings (using 'Echa No. 1' branches as scions and 'Echa No. 1' seedlings as rootstocks) cultivated according to the steps of Example 1 were evaluated under artificially simulated natural conditions. The results showed that the half-lethal temperature of the grafted tea seedlings reached -17.4℃, while that of the cutting seedlings was -10.3℃; the drought index of the grafted tea seedlings was only 0.5, while that of the cutting seedlings was 8.7. This indicates that grafting using seedlings of highly resistant tea varieties as rootstocks can significantly improve the cold and drought resistance of the scion variety.

[0071] Example 3

[0072] Using the cold-resistant 'Yinghong 9' tea cultivar short-cutting seedlings as a control, the cold and drought resistance of grafted tea seedlings (using 'Yinghong 9' branches as scions and 'Echa No. 1' seedlings as rootstocks) cultivated according to the steps of Example 1 were evaluated under simulated natural conditions. The results showed that the half-lethal temperature of the grafted tea seedlings reached -4.8℃, while that of the cutting seedlings was 5.7℃; the drought index of the grafted tea seedlings was 0.1, while that of the cutting seedlings was 2.6. This further demonstrates that grafting using seedlings of highly resistant tea cultivars as rootstocks can significantly improve the cold and drought resistance of the scion variety.

[0073] Examples 1-3 all employed a specialized cutting tool to cut the wedge-shaped double-beveled surface of the spike strips. Specifically, for example... Figures 8 to 11As shown, the special cutting tool includes a base 1. One side of the base 1 is provided with a limiting straight groove 11 for placing the tassel. Two oblique cutting blades 2 are correspondingly arranged in a V-shape on both sides of the limiting straight groove 11. The two oblique cutting blades 2 are slidably placed in the oblique through slots 12 on both sides of the limiting straight groove 11. A rack 22 is provided on the opposite side of the two oblique cutting blades 2. The rack 22 is located at the bottom of the straight groove 21 on the surface of the oblique cutting blade 2. Inside the base 1, each oblique cutting blade 2 is provided with a corresponding long rotating shaft 3. The rack 22 on each oblique cutting blade 2 meshes with the front gear 31 of the corresponding long rotating shaft 3. The rear gears 32 of the two long rotating shafts 3 mesh with each other and are located behind the limiting straight groove 11. Two short shafts 4 parallel to the long shafts 3 are arranged between the two long shafts 3. Each of the two short shafts 4 is equipped with a transition gear 41 that meshes with the nearest rear gear 32. A push rod 5 is arranged between the two transition gears 41. On both sides of the push rod 5 are racks that mesh with the transition gears 41 on the two short shafts 41 respectively. The push rod 5 is slidably placed in the through hole of the base 1. When the through hole and the limiting straight groove 11 are used parallel to each other, pressing down the pressure block 51 on the top of the push rod 5 can realize the closing and cutting of the two oblique cutting blades 2. After the cutting is completed, the pressure block 51 is released, and the push rod 5 moves upward under the rebound of the compression spring 6, and the two oblique cutting blades 2 automatically move upward and separate.

[0074] The above description is only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the protection scope of the present invention.

Claims

1. A method for grafting tea seedlings to shorten the propagation period and improve cold and drought resistance, wherein both the scion and rootstock are of the variety 'Echa No. 1', characterized in that... Includes the following steps, Step 1: Select mature, plump, disease-free, and resilient tea seeds with high fruit set rate after peeling. Sow the tea seeds in a container and germinate them to obtain tea seedlings. Select tea seedlings with a plumule length of more than 6cm, a stem diameter of 0.2cm and no lignification as rootstock. Step 2: Select healthy, disease-free, and plump, non-lignified hard-stemmed tea tree branches that have recently grown as scions, and graft them immediately after harvesting. Step 3: Select a seedling container based on the characteristics of tea seed root growth and development; Step 4: Prepare the grafting seedling substrate. Fill the seedling container with the grafting seedling substrate and water it to make it fully moist. Set aside. The seedling substrate is prepared by mixing slightly acidic peat moss and loess in a 1:1 volume ratio. Step 5: Cut the hypocotyl 3.0cm to 4.0cm above the cotyledons of the tea seedling rootstock from Step 1. Vertically split the hypocotyl cross-section in the middle to serve as the rootstock grafting interface. The depth of the rootstock grafting interface is 1.5cm, and the cotyledons of the tea seedling rootstock are retained. Step 6: Select scions that meet the requirements of Step 2. Using a single-edged knife, make a 1.3cm long wedge-shaped double bevel on both sides 2.5cm below the axillary bud, so that the double bevels meet at the pith. Soak the wedge-shaped double bevel in a 100mg / kg naphthaleneacetic acid solution for 1 hour. Then cut it 0.3cm-0.5cm above the axillary bud to form the scion. Place the prepared scion in a cool, shady place to keep it moist until use. Step 7: Insert the scion from step 6 into the grafting point of the rootstock from step 5, and tie the grafting point with plastic film. After tying, place the grafted tea seedling in a cool, shady place to keep it moist until it is ready for transplanting. Step 8: Plant the grafted tea seedlings from Step 7 into the seedling container from Step 4. The planting depth should be such that the grafting interface is exposed and the cotyledons of the seedling are just buried in the substrate. Step 9: Reasonably control the relative humidity of the air and the relative moisture content of the substrate in the greenhouse, and promptly remove the suckers sprouting from the rootstock; Step 10: Take out the grafted tea seedlings along with the seedling substrate and plant them. The first step also includes a seed harvesting and storage step. Specifically, the tea fruits are harvested and spread out in a cool, ventilated, and dry place, with a thickness of 3cm to 5cm. They are turned over once or twice a day until the tea seeds are separated from the fruit peel. Then, the tea seeds are soaked in clean water for 2 to 3 days. The high-quality tea seeds that sink to the bottom are selected and stored at a low temperature of 5℃ and a relative humidity of 60%. In step six, a special cutting tool is used to cut the spikelet to form a wedge-shaped double bevel. The special cutting tool includes a base (1), one side of which is provided with a limiting straight groove (11) for placing the spikelet. Two oblique cutting blades (2) are arranged in a figure-eight shape on both sides of the limiting straight groove (11). The two oblique cutting blades (2) are slidably placed in the oblique through slots (12) on both sides of the limiting straight groove (11). The two oblique cutting blades (2) face each other. A rack (22) is provided on the side. The rack (22) is located at the bottom of the straight groove (21) on the surface of the oblique cutting blade (2). In the base (1), each oblique cutting blade (2) is provided with a corresponding long rotating shaft (3). The rack (22) on each oblique cutting blade (2) meshes with the front gear (31) of the corresponding long rotating shaft (3). The rear gears (32) of the two long rotating shafts (3) mesh with each other. The rear gears (32) are located behind the limiting straight groove (11). Two short shafts (4) parallel to the long shafts (3) are provided between the two long shafts (3). Each of the two short shafts (4) is provided with a transition gear (41) that meshes with the nearest rear gear (32). A push rod (5) is provided between the two transition gears (41). On both sides of the push rod (5) are racks that mesh with the transition gears (41) on the two short shafts (41). The push rod (5) is slidably placed in the through hole of the base (1). The through hole is parallel to the limiting straight groove (11).

2. The method for shortening the propagation period and improving cold and drought resistance of tea trees by grafting, as described in claim 1, is characterized in that... In step three, the seedling container is a nutrient pot or non-woven bag with a height of 15 cm to 20 cm and a diameter of 8 cm to 10 cm.

3. The method for shortening the propagation period and improving cold and drought resistance of tea trees by grafting, as described in claim 1, is characterized in that... In step nine, when the new shoots of the grafted tea seedlings grow to a height exceeding 30cm, the first shaping pruning is performed 20cm above the grafting point.

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