Koelreuteria paniculata grafting method

Abstract

The invention belongs to the technical field of horticulture, and particularly relates to a koelreuteria paniculata grafting method which comprises the following steps: grafting by using a cambium docking method by taking a koelreuteria paniculata seedling which is more than two years old as a stock and a koelreuteria paniculata stock crown branch as a scion; wherein before grafting, 2mL-3mL of a grafting protective agent No.1 is sprayed at the grafting part of the rootstock; after grafting, 1.5 mL-2. 5mL of grafting healing agent No.2 is sprayed on the grafting part of the scion; the first grafting protective agent is prepared from Cinnamomum camphora, cordate houttuynia, water and ethanol, the second grafting healing agent is prepared from a chitosan solution, an auxin solution, a kinetin solution, Cinnamomum camphora essential oil and Tween 80, and a mixed root system derived from a stock and a scion is formed, so that the defect of grafting incompatibility is fundamentally eliminated.

Description

Technical Field

[0001] This invention belongs to the field of horticultural technology, specifically relating to a grafting method for Koelreuteria paniculata. Background Technology

[0002] Goldenrain tree (Koelreuteria paniculata) is a type of goldenrain tree. Koelreuteria paniculata This is a bud mutation of the common goldenrain tree (Koelreuteria paniculata), a tree belonging to the genus Koelreuteria in the family Sapindaceae. It was developed through bud mutation and selective breeding. It was recognized as a new variety in 2007 and is expected to become a backbone colorful tree species for urban greening in central and northern my country.

[0003] To maintain the desirable golden-yellow foliage, vegetative propagation should be used for Koelreuteria paniculata. However, tissue culture is currently difficult, and propagation by cuttings is still in the experimental research stage and has not yet been scaled up. Grafting is the most reliable propagation method for Koelreuteria paniculata. However, ordinary grafting methods for Koelreuteria paniculata result in slow wound healing, delayed development of vascular tissue at the graft union, and incompatibility in the later stages of grafting. This causes the grafted seedlings to suffer from leaf edge scorching or even wilting in summer, leading to weakened tree vigor and making it difficult to realize its ornamental value. Summary of the Invention

[0004] To address the above problems, this invention provides a grafting method for Koelreuteria paniculata.

[0005] A grafting method for Koelreuteria paniculata includes the following steps: using two-year-old or older Koelreuteria paniculata seedlings as rootstock and Koelreuteria paniculata crown branches as scions, grafting is performed using the cambium butt grafting method; Before grafting, spray 2 mL to 3 mL of grafting protectant No. 1 at the grafting site of the rootstock; after grafting, spray 1.5 mL to 2.5 mL of grafting healing agent No. 2 at the grafting site, including the scion. The grafting protectant No. 1 is made from camphor tree bark, houttuynia cordata, water and ethanol in a ratio of 2000g~2400g: 800g~1200g: 4000mL~4500mL: 6L~10L; The grafting healing agent No. 2 is prepared by chitosan solution, auxin solution, kinetin solution, camphor oil, and Tween 80 in a volume ratio of 1000:2.6~3.0:2~2.4:4~6:2~3. The concentration of chitosan solution is 12g / L~14g / L, the concentration of auxin solution is 1g / L, and the concentration of kinetin solution is 1g / L.

[0006] Preferably, the auxin is indoleacetic acid.

[0007] Preferably, the grafted plant is covered with soil; during the transition period when the leaf color changes from orange-red to golden yellow, 300mL of sesame paste-horse stalk-ferrous sulfate organic fertilizer is applied to the roots each time. The sesame paste-horse stalk-ferrous sulfate organic fertilizer is prepared by a compound and ferrous sulfate in a ratio of 250L:22kg. The complex is prepared from sesame cake fermentation product, water chestnut hydrolyzed amino acid solution, and compound microbial agent; the mass-volume ratio of sesame cake fermentation product to water chestnut hydrolyzed amino acid solution is 200kg~300kg:8L~12L, and the compound microbial agent is Bacillus subtilis and Aspergillus niger, with a bacterial count ratio of Bacillus subtilis to Aspergillus niger of 60:2; the water chestnut hydrolyzed amino acid solution is prepared from water chestnut, water, Actinomadura keratinilytica microbial agent, and sulfuric acid in a ratio of 12000g:4600g:48g:30mol.

[0008] Preferably, the seedlings grown after being covered with soil are called Koelreuteria paniculata seedlings. When the seedlings are growing healthily, they are untied, and after untying, 3mL~10mL of grafting protectant is sprayed on the grafting site.

[0009] Preferably, the grafting protectant is grafting protectant No. 3; The grafting protectant No. 3 is prepared from naphthaleneacetic acid solution, chitosan solution, Tween 80 and camphor oil in a ratio of 1mL:1000mL:2.5mL:5mL. The concentration of the naphthaleneacetic acid solution is 0.08g / L~0.0012g / L and the concentration of the chitosan solution is 12g / L~14g / L.

[0010] Preferably, after mid-August, spray the leaves of every 110 plants with a solution of 5 kg of potassium dihydrogen phosphate and 10 kg of potassium humate diluted 40 times.

[0011] Preferably, the potassium fulvic acid fertilizer contains ≥55% humic acid by mass, ≥50% fulvic acid by mass, and ≥8% potassium oxide by mass.

[0012] Preferably, after grafting, 5 mg / L matrine solution and 3.5 mg / L veratrum biological insecticide are sprayed successively during the budding and leaf expansion stages.

[0013] Preferably, the scion is derived from the middle section of the crown of a superior single tree of the original variety of Goldenrain Tree, and the scion is more than 6cm in length and contains more than 2 healthy and complete leaf buds. The rootstock is a two-year-old seedling of Koelreuteria paniculata with a base diameter of more than 2cm, thick and smooth bark at the base of the stem, and vigorous growth.

[0014] Preferably, grafting is performed when the sap begins to flow.

[0015] Compared with the prior art, the advantages of the present invention are: Using seedlings from a first-and-a-half-generation family of *Koelreuteria paniculata* as rootstock, a low-level cambium grafting method with close-to-the-ground grafting was employed. After mounding soil around the graft, the scion gradually developed roots, eventually forming a mixed root system derived from both the rootstock and scion, thus fundamentally eliminating the drawbacks of graft incompatibility. Furthermore, the inventors discovered that when using this method to graft *Koelreuteria paniculata*, the grafting wound heals quickly, the vascular tissue at the graft union develops rapidly, the survival rate is high, the propagation period is short, the propagation coefficient is high, and the crown formation speed is fast.

[0016] The grafting method for Koelreuteria paniculata of the present invention is simple and easy to implement. Rootstocks and scions are readily available, grafting wounds heal quickly, vascular tissues at the graft union develop rapidly, grafted seedlings have good compatibility, high survival rate, and a short propagation period. Furthermore, it effectively maintains the ornamental characteristics of Koelreuteria paniculata leaves and improves its growth adaptability and stress resistance. Attached Figure Description

[0017] Figure 1 This shows the healing status of grafted Koelreuteria paniculata under different treatments.

[0018] Figure 2 This shows the changes in leaf color parameters of Koelreuteria paniculata in spring under different treatments.

[0019] Figure 3 This shows the changes in leaf color parameters of Koelreuteria paniculata under different treatments during the summer.

[0020] Figure 4 This demonstrates the impact of maintenance measures on the ornamental value and growth of Koelreuteria paniculata.

[0021] Figure 5 This image shows a grafted seedling of *Koelreuteria paniculata* that has just undergone grafting treatment, according to an embodiment of the present invention.

[0022] Figure 6 This image shows a large Koelreuteria paniculata tree developed from a grafted Koelreuteria paniculata seedling according to an embodiment of the present invention.

[0023] Figure 7 This image shows a forest of Koelreuteria paniculata cultivated using the method of this invention. Detailed Implementation

[0024] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific 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 scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods.

[0025] According to an embodiment of the present invention, the rootstock is a two-year-old seedling of *Koelreuteria paniculata* with a basal diameter of 2 cm or more, thick and smooth bark at the base of the stem, and vigorous growth. This ensures unobstructed vascular tissue in the grafted tree, good compatibility, a high grafting success rate, and rapid growth of the grafted seedling.

[0026] According to an embodiment of the present invention, the *Koelreuteria paniculata* seedlings are obtained by sequentially stratifying and germinating *Koelreuteria paniculata* seeds, sowing them in a greenhouse, and then transplanting them outdoors. The resulting *Koelreuteria paniculata* seedlings exhibit excellent characteristics and can be effectively used as rootstock for grafting.

[0027] According to an embodiment of the present invention, the scion is derived from the middle section of a plump bud from the crown of the original species of *Koelreuteria paniculata*, and the scion is at least 6 cm long and contains at least two healthy and complete leaf buds. Therefore, the scion has strong affinity with the rootstock, resulting in a high survival rate of the grafted seedlings and rapid growth after grafting.

[0028] According to an embodiment of the present invention, the scions are harvested in the winter of the year preceding grafting, and then bundled and refrigerated after being wax-sealed. As a result, the scions are of excellent quality, effectively usable for grafting the following spring, and have a high grafting success rate.

[0029] According to an embodiment of the present invention, the grafting method for *Koelreuteria paniculata* further includes: horizontally cutting the rootstock 4 cm above the ground and smoothing the cut; spraying grafting protectant No. 1; making a deep cut 3 cm downwards from the northwest edge of the rootstock cut to obtain a cleft; cutting the scion into a wedge shape from below the lowest bud, ensuring a smooth and flat cut surface with no obvious gaps when the blade is placed flat on the cut surface, with a cut surface length of approximately 3 cm; inserting the prepared scion into the cleft, until the upper edge of the scion cut surface is slightly exposed on the rootstock cut surface, aligning the pale green, viscous cambium layers of the rootstock and scion; and binding and fixing the graft union, spraying grafting healing agent No. 2, and sealing it. This promotes wound healing and the development of vascular tissue at the graft union, resulting in a high survival rate of the grafted seedlings.

[0030] According to an embodiment of the present invention, the grafting method for *Koelreuteria paniculata* further includes: spraying grafting protectant No. 3 after loosening the binding, and mounding soil around the base of the grafted *Koelreuteria paniculata* seedling to cover the graft union tightly. This promotes the healing of the graft union and stimulates the growth of adventitious roots in the scion, which is beneficial to the root development of the grafted seedling, thereby promoting the healthy growth of the grafted seedling.

[0031] According to an embodiment of the present invention, after the scion of *Koelreuteria paniculata* sprouts and grows normally, aphids are controlled by the plant-derived biological agent matrine solution in the early stage of leaf expansion, ensuring that the young buds do not curl or become deformed, and that the young leaves are intact and free of insect spots or patches.

[0032] According to an embodiment of the present invention, aphid control is achieved by spraying Veratrum extract during the later stage of leaf expansion. This effectively controls aphids and ensures healthy seedling growth.

[0033] According to an embodiment of the present invention, a bio-fermented sesame paste-horse stalk-ferrous sulfate fertilizer is applied to the roots during the preferred spring foliage coloring period. This results in the goldenrain tree having bright, vibrant foliage and high ornamental value.

[0034] According to an embodiment of the present invention, during the peak growth period of Koelreuteria paniculata in summer, foliar spraying with potassium dihydrogen phosphate mixed with lignite-derived potassium humate improves the health of the leaves and enhances the saturation and brightness of the golden color.

[0035] According to embodiments of the present invention, spraying plant-derived insecticides of Sophora flavescens and Veratrum nigrum during the spring leaf expansion period to control aphids, combined with root application of bio-fermented fertilizer and foliar topdressing, greatly reduces the damage caused by scale insects and the incidence of sooty mold and anthracnose during the hot and humid season, and improves the health of Koelreuteria paniculata leaves.

[0036] In this invention, the preparation methods of grafting protectant No. 1, grafting healing agent No. 2, grafting protectant No. 3, and sesame paste-horse stalk-ferrous sulfate organic fertilizer are as follows: 1. The preparation method of grafting protectant No. 1 includes the following steps: (1.1) Take 2000g~2400g of fresh, disease-free leaves of *Cinnamomum camphora*, cut them into pieces less than 1cm, add 150mL~250mL of water, and homogenize them into a slurry with a particle size less than 90µm. Pour the slurry into 6L of 70% ethanol solution, stir and extract, and then perform ultrasonic-assisted extraction for 45min. Filter through a 10µm filter membrane, collect the filtrate, and remove the alcohol and some water by rotary evaporation at 38℃~48℃ and 60r / min~80r / min to obtain a concentrated extract.

[0037] (1.2) Take 800g-1200g of fresh Houttuynia cordata leaves, cut them into pieces less than 1cm, add 80mL-120mL of water, and pulverize them into a homogenate with a particle size less than 90µm. Pour the homogenate into 1L-3L of 72% ethanol solution, stir and extract, and then extract with ultrasonic assistance for 35min. Filter through a 10µm filter membrane, collect the filtrate, and evaporate it by rotary evaporation at 38℃-48℃ and 60r / min-80r / min to remove alcohol and some water, to obtain a concentrated extract.

[0038] (1.3) Dissolve the concentrated pastes from (1.1) and (1.2) in 4L of purified water, filter through a 0.45µm filter membrane, and the filtrate is grafting protectant No. 1. 2. The preparation method of grafting healing agent No. 2 includes the following steps: Add 2.6 mL to 3.0 mL of 1 g / L kinetin solution to 1 L of chitosan solution with a concentration of 12 g / L to 14 g / L, and stir for 10 min. Then add 2 mL to 2.4 mL of 1 g / L indoleacetic acid solution and stir for 5 min. While stirring, add 2.5 mL of Tween 80 dropwise and stir for 15 min. Then add 4 mL to 6 mL of camphor oil while stirring and continue stirring for 30 min to obtain a crude emulsion of camphor oil. Homogenize the crude emulsion at 10000 rpm for 8 min using a high-speed homogenizer to prepare grafting healing agent No. 2.

[0039] 3. The preparation method of grafting protectant No. 3 includes the following steps: Add 1 mL of 1 g / L naphthaleneacetic acid (NAA) solution to 1 L of 13 g / L chitosan solution, then add 2.5 mL of Tween 80 and stir for 15 min. While stirring, add 5 mL of camphor oil and continue stirring for 30 min to obtain a crude emulsion of camphor oil. Homogenize the crude emulsion at 8000 rpm for 5 min using a high-speed homogenizer to prepare grafting protectant No. 3. Naphthaleneacetic acid is abbreviated as NAA.

[0040] 4. The preparation method of sesame paste-horse stalk-ferrous sulfate organic fertilizer includes the following steps: (4.1) Crush the horse hoof slices and pass them through a 40-mesh sieve; take 12 kg and put it into a corrosion-resistant container, add 4.6 kg of water with a pH of 7.2, and mix in 48 g of Actinomadura keratinilytica bacterial agent, EU637009, strain WCC-2265T, requiring a viable count of 2×10⁻⁶. 10 CFU / g was mixed thoroughly and kept moist by spraying water every 12 hours at 42℃~45℃ for 5 days to treat stubborn keratin through biodegradation. Then, 30L of 1.0mol / L sulfuric acid was added and the reaction was carried out for 12 hours. The acid was removed by evaporation to obtain a hydrolyzed amino acid solution of horse hoof.

[0041] (4.2) Inject 260kg of sesame cake fermentation species into 10L of water chestnut hydrolyzed amino acid solution, stir evenly, add compound microbial agent, which is Bacillus subtilis and Aspergillus niger, with the ratio of Bacillus subtilis and Aspergillus niger being 60:2, mix thoroughly and stir evenly so that the total number of bacteria in the mixed material is not less than 700,000 per gram.

[0042] (4.3) Add 22 kg of ferrous sulfate to 250 L of the product (4.2), add a large amount of water to completely dissolve it, and finally the liquid level reaches 50 cm. Stir evenly and chelate for one week to obtain sesame paste-horse saddle-ferrous sulfate organic fertilizer.

[0043] Example 1 1. The preparation method of grafting protectant No. 1 includes the following steps: (1.1) Take 2200g of fresh, disease-free leaves of *Cinnamomum camphora*, cut them into pieces less than 1cm in size, add 200mL of purified water, and homogenize them using a Joyoung B700 blender until the particle size is less than 90µm. Pour the homogenate into 6L of 70% ethanol solution and stir for 150min. Then, perform ultrasonic extraction at 500W and 50kHz for 45min. Filter the solution through a 10µm filter membrane, collect the filtrate, and remove the alcohol and some water using a rotary evaporator at 38℃ and 60r / min to obtain 350mL of concentrated extract.

[0044] (1.2) Take 1000g of fresh Houttuynia cordata leaves, cut them into pieces less than 1cm, add 100mL of purified water, and use a Joyoung B700 blender to grind and homogenize the mixture to a particle size of less than 90µm. Pour the homogenate into 2L of 72% ethanol solution, stir and extract for 100min, then use 250W, 50kHz ultrasonic-assisted extraction for 35min. Filter through a 10µm filter membrane, collect the filtrate, and use a rotary evaporator to remove alcohol and some water at 38℃ and 6080r / min to obtain 150mL of concentrated extract.

[0045] (1.3) Dissolve the concentrated pastes of (1.1) and (1.2) in 4L of pure water, filter through a 0.45µm filter membrane, and the filtrate is grafting protectant No.1.

[0046] 2. The preparation method of grafting healing agent No. 2 includes the following steps: (2.1) Take 1g of indoleacetic acid, dissolve it in 100mL of 95% ethanol, stir continuously at 27℃ until completely dissolved, slowly add deionized water to 950mL, then pour it into a 1000mL volumetric flask, add deionized water to make up to volume, put it into a brown glass bottle and store it in the dark at low temperature. Indoleacetic acid is abbreviated as IAA.

[0047] (2.2) Take 1g of kinetin, dissolve it in 10mL of 1N hydrochloric acid, stir continuously at 25℃, and slowly add deionized water to 950mL after complete dissolution. Then pour it into a 1000mL volumetric flask, add deionized water to make up to volume, and store it in a brown glass bottle in the dark at low temperature. Kinetin is abbreviated as KT.

[0048] (2.3) Prepare a eutectic solvent with choline chloride as the hydrogen bond acceptor and ethylene glycol as the hydrogen bond donor in a molar ratio of 1:5. Add deionized water to make the mixed solvent system contain 30% water. Transfer it to a flat-bottomed flask and stir at 100 rpm for 80 min in a water bath at 65°C to obtain a homogeneous and transparent solution, i.e., the eutectic solvent. Store it at 4°C in a sealed container away from light for later use.

[0049] Collect leaves of *Cinnamomum camphora*, wash and dry them, then crush them. Add 1000g of crushed *Cinnamomum camphora* to a eutectic solvent at a ratio of 1g:7mL, and homogenize at 18000rpm for 3min.

[0050] Pour into a 10L round-bottom thick-walled flask, place it in an ultrasonic cleaner, and perform ultrasonic extraction at 300W, 40kHz frequency, and 40min.

[0051] Simmer for 6 hours until no obvious oil droplets are visible in the reflux liquid. Stop distillation and let stand at low temperature until the oil and water completely separate. Collect the oil layer and dehydrate with anhydrous sodium sulfate to obtain camphor essential oil.

[0052] (2.4) Weigh 13g of chitosan and dissolve it in 1L of a 0.8% dilute glacial acetic acid solution. Stir the solution in a water bath at 35°C until the chitosan is fully dissolved to obtain a chitosan solution.

[0053] (2.5) Add 2.8 mL of the kinetin solution prepared in (2.2) to the chitosan solution in (2.4), stir for 10 min, then add 2.2 mL of the indoleacetic acid solution prepared in (2.1), stir for 5 min; while stirring, add 2.5 mL of Tween 80 dropwise, stir for 15 min; while stirring, add 5 mL of the camphor oil prepared in (2.3), continue stirring for 30 min, and obtain the camphor oil composite crude emulsion. Homogenize the crude emulsion at 10000 rpm for 8 min using a high-speed homogenizer to prepare grafting healing agent No. 2.

[0054] 3. The preparation method of grafting protectant No. 3 includes the following steps: Take 1g of naphthaleneacetic acid and dissolve it in 150mL of 95% ethanol. Stir continuously at 27℃ until completely dissolved. Slowly add deionized water to 950mL, then pour into a 1000mL volumetric flask and dilute with deionized water. Weigh 13g of chitosan and dissolve it in 1L of 0.8% dilute glacial acetic acid solution. Stir in a water bath at 35℃ until the chitosan is fully dissolved. Add 1mL of NAA stock solution and stir for 10min. While stirring, add 2.5mL of Tween 80 dropwise to the chitosan solution and stir for 15min. While stirring, add 5mL of camphor oil (prepared in step 2.3) dropwise and continue stirring for 30min to obtain a crude emulsion of camphor oil composite. Homogenize the crude emulsion at 8000rpm for 5min using a high-speed homogenizer to prepare grafting protectant No. 3.

[0055] 4. The preparation method of sesame paste-horse stalk-ferrous sulfate organic fertilizer includes the following steps: (4.1) Crush the horse hoof slices and pass them through a 40-mesh sieve; take 12 kg and put it into a corrosion-resistant container, add 4.6 kg of water with a pH of 7.2, and mix in 48 g of Actinomadura keratinilytica bacterial agent, EU637009, strain WCC-2265T, requiring a viable count of 2×10⁻⁶. 10 CFU / g was mixed thoroughly and kept moist by spraying water every 12 hours at 42℃ for 5 days to treat stubborn keratin through biodegradation. Then, 30L of 1.0mol / L sulfuric acid was added and stirred thoroughly with a glass rod, and the reaction was allowed to proceed for 12 hours. The solution was then evaporated and concentrated to 10L in a water bath below 90℃, and slowly poured into another corrosion-resistant container containing 20L of water. This process of evaporation and deacidification was repeated three times to obtain a water chestnut hydrolysate amino acid solution.

[0056] (4.2) Crush 260kg of sesame cake into pieces with a diameter of less than 1cm, put 60kg of millet bran into a fermentation tank with a length of 300cm, a width of 200cm and a depth of 90cm, add 240L of water, stir evenly, the sesame cake is required to have a crude protein content of more than 40% and an iron content of more than 900mg / kg; slowly inject 10L of the water chestnut hydrolyzed amino acid solution in (1) of 4, stir evenly, add compound microbial agent, the compound microbial agent is Bacillus subtilis and Aspergillus niger, Bacillus subtilis and Aspergillus niger are mixed and stirred evenly at a ratio of 60:2, so that the total number of bacteria in the mixed material is not less than 700,000 / g.

[0057] Record the center temperature of the fertilizer compost pile and the ambient temperature daily at 10:00 AM. Turn the compost pile every 2 days and add moisture to maintain a moisture content of 62% throughout the composting process. The composting time is 30 days. After composting, accurately weigh the compost and take a uniform sample of at least 5 kg. Determine the moisture content, protein nitrogen, total nitrogen, and mineral nitrogen (NH4). + +NO3 - The total amino acid and organic carbon content were measured, and the maturity and protein nitrogen degradation rate of the oilseed cake treated with the compound microbial agent were calculated. Maturity was measured using the humic acid E4 / E6 ratio, which was determined by extracting the sample with distilled water at a mass ratio of 20:1. After filtration, the absorbance of the filtrate was measured at wavelengths of 465 and 665 nm using a spectrophotometer, and the ratio was calculated and denoted as E4 / E6. Maturity was required to have a carbon / nitrogen ratio less than 6.50, a protein nitrogen degradation rate greater than 22%, a humic acid E4 / E6 ratio less than 3.50, and a total amino acid content greater than 27.3 mg / g.

[0058] (4.3) Add 22 kg of ferrous sulfate to 250 L of the product (4.2), add a large amount of water to completely dissolve it, and finally the liquid level reaches 50 cm. Stir evenly and chelate for one week to obtain sesame paste-horse saddle-ferrous sulfate organic fertilizer.

[0059] Example 2 The grafting protectant No. 1, grafting healing agent No. 2, grafting protectant No. 3, and sesame paste-horse stalk-ferrous sulfate organic fertilizer used in this embodiment were all prepared in Example 1.

[0060] According to the grafting method of Koelreuteria paniculata of the present invention, the grafting of Koelreuteria paniculata is carried out according to the following steps: (1) Seed collection and pretreatment In October 2020, when the fruit turns reddish-brown, it is the appropriate time to collect the seeds. Select healthy Goldenrain Trees with few pests and diseases during the summer and autumn, and collect the plump fruits. Then, remove the fruit stalks from the collected fruits, and promptly sun-dry or spread them out to dry in the shade. After the fruits crack open, thresh the seeds by beating them, and then clean them using the screening method. The steps for cleaning the seeds by screening are: soaking the seeds in 50℃ water for 24 hours, treating them in a 0.4% potassium permanganate solution for 4 hours, soaking them in 40℃ water for 24 hours, and disinfecting them with a 0.4% potassium permanganate solution for 2 hours.

[0061] (2) Stratification for germination In November 2020, before the soil freezes, select a high, dry, well-drained, sheltered outdoor location and dig a pit. The pit should be 120cm deep and 100cm wide. Lay a 20cm thick layer of fresh furnace ash (passed through a 2cm sieve) at the bottom, and place a bundle of straw rakes at each corner for ventilation. Mix the cleaned seeds (after sieving) with damp sand and place the mixture in the pit, filling it to about 15cm from the ground. Cover the pit with 10cm of river sand, and then cover the sand with a 10cm thick layer of straw mats to promote germination. The seed-to-sand volume ratio should be 1:4, and the sand should ideally have a moisture content of 40%. Fill the pit with the sand-seed mixture.

[0062] (3) Greenhouse tray sowing Sowing was carried out in mid-March 2021. A seedling substrate was prepared by mixing peat moss, vermiculite, and perlite in a 1:1:1 ratio. The substrate was then poured into clean seedling trays, and holes were made in the substrate with a bamboo skewer. One pre-germinated seed was placed in each hole. After sowing one tray, the tray was covered with the substrate, thoroughly watered, and kept at a suitable humidity level before being placed in a greenhouse. The greenhouse temperature was 25℃, and the relative humidity was 75%. It should be noted that a greenhouse temperature of 20℃~30℃ and a relative humidity above 70% will achieve the desired results.

[0063] (4) Rootstock planting The planting site should have loose, well-aerated soil with good water retention and drainage, and a certain level of fertility, free from underground pests and pathogens. Transplanting should be done in mid-May 2021 when the seedlings in the plug trays reach approximately 10cm in height, with a spacing of 30cm x 15cm. For the first two weeks after transplanting, provide shade as needed to prevent sunscald.

[0064] (5) Apply base fertilizer and prepare scions In early November 2022, before the soil froze, four shallow trenches were dug in the top 20cm of soil around the rootstock. These trenches were evenly distributed radially in the four cardinal directions (east, south, west, and north) of the rootstock, each 60cm long, 20cm deep, and 20cm wide. 1000g of bio-organic fertilizer was mixed evenly with 8kg of well-rotted sheep manure and spread in the trenches, then covered with soil and watered. The soil at the 20cm depth around the rootstock of the *Koelreuteria paniculata* rootstock thawed and warmed up 6-11 days earlier than the control group without sheep manure. The bio-organic fertilizer was a microbial compound organic fertilizer with an effective live bacteria count ≥0.3 billion / g, an organic matter content ≥22%, and an NPK ≥26%.

[0065] In mid-to-late November 2022, cuttings were collected from the crown of the original species of *Koelreuteria paniculata*. Scions were cut from the middle section with plump buds, each scion containing at least two healthy, intact leaf buds and a length of at least 6 cm. The scions were quickly dipped in 93℃ paraffin wax for sealing, ensuring a thin and tight wax layer. The wax-sealed scions were then bundled and refrigerated.

[0066] (6) Grafting construction The first step is to select rootstock. Choose a 2020-planted *Koelreuteria paniculata* tree with a base diameter of over 2cm, thick bark at the base of the trunk, and a smooth surface. Before grafting, spray the grafting site of the rootstock with 2.5mL of grafting protectant No. 1 to inhibit pathogenic microorganisms. The second step is to prepare the scion. Make a wedge shape below the lowest bud of the scion, ensuring a smooth and even cut surface. The cut should be about 3cm long, with no obvious gaps when the blade is placed flat on the cut surface. The third step is to split the rootstock. Using strong pruning shears, make a horizontal cut 4cm above the ground. Quickly trim the cut with a grafting knife, making a 3cm deep cut from the northwest edge of the rootstock cut to the center. Immediately insert the prepared scion into the split, ensuring the upper edge of the scion's cut surface is slightly exposed on the rootstock cut. Align the pale green, viscous cambium layers of the rootstock and scion. Quickly tie the scion to the top of the split with white hemp bark to secure it, ensuring the rootstock tightly grips the scion. Immediately spray 2mL of grafting healing agent No. 2 onto the grafting area, including the scion. Then, use high-elasticity grafting film to bind and tightly wrap the graft union. The fourth step is to mound soil around the base of the grafted *Koelreuteria paniculata* seedling to cover the grafting area, promote healing, and stimulate the growth of adventitious roots on the scion. Step 5: Once the scion sprouts and grows to 7cm, approximately from late April to early May, spray with a 5mg / L solution of matrine to control aphids. It should be noted that spraying with matrine solution when the scion grows to 6cm-9cm will achieve the desired effect. Step 6: Observe the growth of the scion. Once the leaves are fully expanded, two weeks after the first aphid control, spray again with a 3.5mg / L active ingredient in a Veratrum biological insecticide, depending on the aphid damage. Step 7: During the transition from orange-red to golden-yellow leaf color, begin applying 300mL of a sesame paste-horse stalk-ferrous sulfate fertilizer to the roots. Step 8: Assuming the grafted Koelreuteria paniculata seedlings are growing healthily, loosen the binding at the graft union before the end of May 2023. Step 9: After loosening the binding, spray the graft union with 3-10mL of grafting protectant No. 3. Step 10: Check the soil covering at the graft union, remove any rootstock suckers, and cover with soil again. Step 11: From June to late July, apply sesame paste-horse stalk-ferrous sulfate fertilizer twice. Step 12: From mid-August to the end of September, foliar spray with potassium dihydrogen phosphate mixed with potassium humate fertilizer three times. Each time, spray 5 kg of potassium dihydrogen phosphate and 10 kg of potassium humate fertilizer diluted 40 times for every 110 plants. The potassium humate fertilizer should contain ≥55% humic acid, ≥50% fulvic acid, and ≥8% potassium oxide.

[0067] Figure 5 The image shows a newly grafted *Koelreuteria paniculata* seedling. After grafting, the scion sprouted and turned orange-red. Figure 6 This shows a large, golden-leaved Koelreuteria paniculata tree developed from a grafted seedling, with a crown that has formed and turned golden yellow. Figure 7 The cultivated Koelreuteria paniculata forest shows a golden-yellow canopy in autumn.

[0068] Effect verification Experiment 1 A grafting method for Koelreuteria paniculata, the treatments include: CK, F1CK, F1SM, F1SMP1, and F1SMP1C2. The survival rate was counted in early November of the year of grafting, and the results are shown in Table 1.

[0069] Among them, CK represents ordinary rootstock control; F1CK represents F1 rootstock control; F1SM represents F1 rootstock + sheep manure base fertilizer for temperature increase; F1SMP1 represents F1 rootstock + sheep manure base fertilizer for temperature increase + grafting protection agent No. 1; F1SMP1C2 represents F1 rootstock + sheep manure base fertilizer for temperature increase + grafting protection agent No. 1 + grafting healing agent No. 2.

[0070] Table 1. Effect of the treatment technology of this invention on grafting survival rate. Note: Different lowercase letters in the same column indicate significant differences at the 0.05 level.

[0071] Experiment 2 A grafting method for *Koelreuteria paniculata*, involving the following treatments: CK, F1CK, F1SM, F1SMP1, F1SMP1C2, and F1SMP1C2P3. The graft healing status was assessed in late June of the grafting year, and the results are shown below. Figure 1 .

[0072] Among them, CK represents ordinary rootstock control; F1CK represents F1 rootstock control; F1SM represents F1 rootstock + sheep manure base fertilizer with temperature increase; F1SMP1 represents F1 rootstock + sheep manure base fertilizer with temperature increase + grafting protectant No. 1; F1SMP1C2 represents F1 rootstock + sheep manure base fertilizer with temperature increase + grafting protectant No. 1 + grafting healing agent No. 2; F1SMP1C2P3 represents F1 rootstock + sheep manure base fertilizer with temperature increase + grafting protectant No. 1 + grafting healing agent No. 2 + grafting protectant No. 3.

[0073] Experiment 3 A grafting method for *Koelreuteria paniculata*, using grafts CK, F1CK, F1SmP1C2P3, F1SmP1C2P3Se, and F1SmP1C2P3SePf, involves observing leaf color parameters at late April (4 weeks after grafting) and late June (8 weeks after grafting). The lightness (L*) value, hue (a*) value, and b* value are measured, and the chroma (C*) value is calculated using the following formula: C* = (a*² + b*²)¹ / ². Where L* reflects the lightness of the color; a* reflects the hue of red and green attributes; b* reflects the hue of yellow and blue attributes; and C* represents the vertical distance to the L* axis, with a greater distance resulting in a higher chroma.

[0074] Among them, CK represents the ordinary rootstock control; F1CK represents the F1 rootstock control; F1SmP1C2P3 represents F1 rootstock + sheep manure base fertilizer for warming + grafting protectant No. 1 + grafting healing agent No. 2 + grafting protectant No. 3; F1SmP1C2P3Se represents F1 rootstock + sheep manure base fertilizer for warming + grafting protectant No. 1 + grafting healing agent No. 2 + grafting protectant No. 3 + sesame paste root base fertilizer; F1SmP1C2P3SePf represents F1 rootstock + sheep manure base fertilizer for warming + grafting protectant No. 1 + grafting healing agent No. 2 + grafting protectant No. 3 + sesame paste root base fertilizer + potassium humate foliar fertilizer.

[0075] See results Figure 2 , Figure 3 This indicates that fertilization can improve the brightness and color saturation of the leaves of the Goldenrain Tree, thereby improving its ornamental effect.

[0076] Experiment 4 A grafting method for Koelreuteria paniculata includes treatments such as CK, F1CK, F1PO, and F1POPe. From late September to early October, the leaf color parameters, specific leaf weight, canopy leaf density, number of main branches and branch and leaf distribution, and canopy width of Koelreuteria paniculata are observed.

[0077] Among them, CK represents the ordinary rootstock control; F1CK represents the F1 rootstock control; F1PO is an abbreviation of F1SmP1C2P3SePf, representing F1 rootstock + sheep manure base fertilizer for warming + grafting protectant No. 1 + grafting healing agent No. 2 + grafting protectant No. 3 + sesame paste root base fertilizer + potassium humate foliar fertilizer; F1POPe represents F1 rootstock + sheep manure base fertilizer for warming + grafting protectant No. 1 + grafting healing agent No. 2 + grafting protectant No. 3 + sesame paste root base fertilizer + potassium humate foliar fertilizer + plant-derived biological insecticide, the plant-derived insecticide being matrine solution and veratrum extract.

[0078] See results Figure 4 The measured indicators are all related to the beauty of a single Koelreuteria paniculata plant and its growth status.

[0079] The rootstock of this invention is beneficial to the full expression of the target traits of the scion because changes in protein activity between the rootstock and scion, as well as long-distance transport of substances such as RNA across grafting, can affect gene expression and thus affect the plant phenotype. The transmission of genetic information of small RNAs is related to DNA methylation, and changes in DNA methylation are related to gene expression, which also affects the plant phenotype.

[0080] Changes in protein activity between rootstock and scion, as well as the long-distance transport of substances such as RNA across grafting, can affect gene expression and thus the plant phenotype. The transmission of genetic information by small RNAs is related to DNA methylation, and changes in DNA methylation are related to gene expression, which also affects the expression of desirable plant traits, including ornamental traits. In grafts with good compatibility, the rootstock and scion can completely or partially fuse to form a symbiotic relationship, which can grow and bear fruit for a long time. In the early stages of grafting, an isolation layer caused by the cutting wound covers the entire grafting surface. This isolation layer is composed of cell wall remnants of damaged cells and dense material with high electron density. Its main function is to seal the wound, prevent the outflow of large amounts of organic matter and ions, and protect the physiological activity of the remaining living cells. Numerous Golgi bodies are often found in the cells of the isolation layer on both sides, secreting pectin, carbohydrates, and proteins to promote initial adhesion between the rootstock and scion. Subsequently, intercellular protrusions resembling plasmodesmata form between the cells on both sides of the isolation layer, covered with a layer of lipids and waxes. This structural connection allows for the exchange of small amounts of water, nutrients, and molecular signals between the rootstock and scion. The subsequent formation of cross-bridge structures further strengthens the connection. The parenchyma cells adjacent to the isolation layer resume division, especially near the scion, forming callus tissue. In the grafting of garden trees, callus tissue can be formed by the dedifferentiation of cells in the pith, wood rays, cambium, and cortex. The formation of numerous plasmodesmata between the callus tissues further strengthens the connection between the rootstock and scion cells at the graft union. Although the newly formed callus cells undergo axial elongation, they are still relatively small compared to the existing parenchyma cells. As the callus expands, it exerts growth pressure on the isolation layer and can also absorb necrotic cell components from the isolation layer, leading to its disappearance. The callus tissue in the scion and rootstock interlocks, reinforcing the connection between them. The callus then proliferates and redifferentiates into new vascular bundles. The reconnection of the vascular bundles between the rootstock and scion marks the completion of healing at the grafting wound site.

[0081] In summary, the key aspects of the grafting method for *Koelreuteria paniculata* provided by this invention lie in the selection of rootstock, grafting time, rootstock disinfection, soil warming fertilizer, grafting healing protectant, compound protectant after loosening the binding, application of bio-organic fertilizer to the roots, foliar spraying of humic acid complex fertilizer, and biological agents for the control of harmful organisms. This method combines the practicality of traditional garden tree seedling production with scientific principles, ensuring good reproducibility and facilitating replication and promotion in practice.

[0082] It should be noted that when numerical ranges are mentioned in the claims of this invention, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. To avoid redundancy, the present invention describes preferred embodiments.

[0083] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0084] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A grafting method for Koelreuteria paniculata, characterized in that, Includes the following steps: Using two-year-old or older seedlings of Koelreuteria paniculata as rootstock and crown branches of the original Koelreuteria paniculata species as scions, grafting is performed using the cambium grafting method. Before grafting, spray 2 mL to 3 mL of grafting protectant No. 1 at the grafting site of the rootstock; after grafting, spray 1.5 mL to 2.5 mL of grafting healing agent No. 2 at the grafting site, including the scion. The grafting protectant No. 1 is made from camphor tree bark, houttuynia cordata, water and ethanol in a ratio of 2000g~2400g: 800g~1200g: 4000mL~4500mL: 6L~10L; The grafting healing agent No. 2 is prepared by chitosan solution, auxin solution, kinetin solution, camphor oil, and Tween 80 in a volume ratio of 1000:2.6~3.0:2~2.4:4~6:2~3. The concentration of chitosan solution is 12g / L~14g / L, the concentration of auxin solution is 1g / L, and the concentration of kinetin solution is 1g / L.

2. The grafting method for Koelreuteria paniculata according to claim 1, characterized in that, The auxin is indoleacetic acid.

3. The grafting method for Koelreuteria paniculata according to claim 1, characterized in that, After grafting, the soil should be covered; during the transition period when the leaf color changes from orange-red to golden yellow, apply 300mL of sesame paste-horse stalk-ferrous sulfate organic fertilizer to the roots each time. The sesame paste-horse stalk-ferrous sulfate organic fertilizer is prepared by a compound and ferrous sulfate in a ratio of 250L:22kg. The complex is prepared from sesame cake fermentation product, water chestnut hydrolyzed amino acid solution, and compound microbial agent; the mass-volume ratio of sesame cake fermentation product to water chestnut hydrolyzed amino acid solution is 200kg~300kg:8L~12L, and the compound microbial agent is Bacillus subtilis and Aspergillus niger, with a bacterial count ratio of Bacillus subtilis to Aspergillus niger of 60:2; the water chestnut hydrolyzed amino acid solution is prepared from water chestnut, water, Actinomadura keratinilytica microbial agent, and sulfuric acid in a ratio of 12000g:4600g:48g:30mol.

4. The grafting method for Koelreuteria paniculata according to claim 5, characterized in that, After being covered with soil, the seedlings of Koelreuteria paniculata will grow. When the seedlings are growing healthily, they will be untied. After untying, 3 mL to 10 mL of grafting protectant will be sprayed on the grafting site.

5. The grafting method for Koelreuteria paniculata according to claim 3, characterized in that, The grafting protectant is grafting protectant No. 3; The grafting protectant No. 3 is prepared from naphthaleneacetic acid solution, chitosan solution, Tween 80 and camphor oil in a ratio of 1mL:1000mL:2.5mL:5mL. The concentration of the naphthaleneacetic acid solution is 0.08g / L~0.0012g / L and the concentration of the chitosan solution is 12g / L~14g / L.

6. The grafting method for Koelreuteria paniculata according to claim 1, characterized in that, After mid-August, spray the leaves of every 110 plants with a solution of 5 kg of potassium dihydrogen phosphate and 10 kg of potassium humate diluted 40 times.

7. The grafting method for Koelreuteria paniculata according to claim 6, characterized in that, The potassium fulvic acid fertilizer contains ≥55% humic acid by mass, ≥50% fulvic acid by mass, and ≥8% potassium oxide by mass.

8. The grafting method for Koelreuteria paniculata according to claim 1, characterized in that, After grafting, spray with 5 mg / L matrine solution and 3.5 mg / L Veratrum biological insecticide during the budding and leaf expansion stages, respectively.

9. The grafting method for Koelreuteria paniculata according to claim 1, characterized in that, The scion is derived from the middle section of the crown of a superior single tree of the original variety of Goldenrain Tree with plump buds, and the scion is more than 6cm long and contains more than 2 healthy and complete leaf buds. The rootstock is a two-year-old seedling of Koelreuteria paniculata with a base diameter of more than 2cm, thick and smooth bark at the base of the stem, and vigorous growth.

10. The grafting method for Koelreuteria paniculata according to claim 1, characterized in that, Grafting should be performed when the sap begins to flow.

Images