A high survival rate method for grafting Pinus sylvestris var. mongolica onto Pinus tibetica in high-altitude cold regions

Abstract

The present invention discloses a high survival rate method for grafting Pinus sylvestris var. mongolica onto Pinus tibetana in high-altitude cold regions, which improves the adaptability and survival rate of grafting through multi-dimensional innovation. A double interface with an ascending slope on the sunny side of the Pinus sylvestris var. mongolica stock and a descending slope on the shady side is provided to match the double wedge-shaped part of the scion bud of Pinus tibetana to improve the contact surface between the stock and the scion; a photothermal responsive shape memory polymer strap is used for fixation to inhibit pathogens and promote callus differentiation; a double-layer protective structure is constructed, with a built-in moisture control group in the inner moisturizing and breathable membrane to maintain the interface humidity ≥ 60%, and an outer anti-UV windproof net to intelligently adjust to cope with wind, sand and strong light. Further, callus differentiation is precisely regulated by pre-embedded pH-responsive cellulose microspheres, or an intelligent temperature control membrane and an aerogel layer are added to stabilize the temperature difference, and the scion bud is combined with low-temperature acclimation and abscisic acid treatment to enhance frost resistance. This method significantly improves the grafting survival rate and is suitable for the efficient introduction of Pinus tibetana in high-altitude cold regions, with strong process synergy and high environmental adaptability.

Description

Technical Field

[0001] The present invention relates to the technical field of Mongolian pine grafting, and more particularly to a method for grafting Mongolian pine onto Tibetan white pine in high-altitude cold regions with a high survival rate. Background Art

[0002] Plant grafting technology faces enormous challenges in alpine regions due to the harsh environment of extreme low temperatures, strong ultraviolet radiation, and frequent strong winds. As a cold-resistant rootstock, Pinus sylvestris var. mongolica is widely used in afforestation in alpine regions, and there is already a certain research foundation for its grafting technology with species such as Korean pine and Chinese pine. In the invention patent with publication number CN118020513A, it is proposed to protect the scion buds by double-covering plastic bottles and applying potassium fertilizer to promote lignification for the grafting of Pinus sylvestris var. mongolica onto Korean pine, which significantly improved the survival rate of the grafted Pinus sylvestris var. mongolica onto Korean pine. However, this method is mainly used for Korean pine scions, and whether its technical logic (such as protection measures and fertilizer ratios) is applicable to other pine species still needs to be verified, especially the grafting research of the unique species of Tibetan white pine is still blank.

[0003] Tibetan white pine has both ecological restoration and economic value. Its dense, resilient wood holds great potential for ecological restoration in arid western China. While its global distribution is relatively limited, it enjoys strong market demand due to its large, thin-skinned, fleshy seeds, high nutritional value, and excellent flavor. However, naturally grown Tibetan white pine takes twenty years to produce cones.

[0004] To date, there has been no systematic research on the grafting technology of Tibetan white pine and Scots pine. Existing literature primarily focuses on the grafting compatibility of Scots pine with common tree species such as Korean pine and Chinese pine. However, due to differences in physiological characteristics of Tibetan white pine (such as slow callus differentiation rate and special low-temperature metabolic pathways), traditional grafting methods are difficult to directly apply. For example, the static protection of plastic bottles used in the invention patent CN118020513A can provide windproof and heat insulation, but it fails to address the periodic micro-displacement of the scion-rootstock interface caused by the temperature difference between day and night in high-altitude areas. Due to the difference in thermal expansion coefficients between the Tibetan white pine scion and the Scots pine rootstock, shear stress is easily generated under temperature fluctuations, resulting in only partial connection of the internal vascular bundles of the seemingly healed interface. Furthermore, the Tibetan white pine scion bud is more sensitive to humidity fluctuations, and a closed environment can easily lead to mildew or freeze-thaw damage at the interface, resulting in a low survival rate.

[0005] From the perspective of rootstock-scion interaction mechanisms, the compatibility of Tibetan white pine and Scots pine remains unclear. Existing grafting techniques are mostly based on morphological matching (such as cambium alignment), but the vascular structure and hormone response characteristics of Tibetan white pine differ significantly from those of Korean pine. While the cleft grafting method employed in patent CN118020513A is suitable for Korean pine, its scion bud cut length (3-5 cm) and fertilization strategy (exclusive potassium fertilizer) fail to meet the specific nutrient distribution and interface healing requirements of Tibetan white pine. Tibetan white pine scions contain unique terpene defense substances, such as α-pinene, which is 2.3 times higher than that of Korean pine. When these substances come into contact with Scots pine rootstocks, they trigger the rootstock's wound response system to release large amounts of methyl jasmonate. The metabolites of the two form a collision zone at the interface, inhibiting lignin deposition and attracting saprophytic colonization. Patent CN118020513A only uses carbendazim for broad-spectrum sterilization, failing to specifically regulate the immune response between the stock and scion, leading to necrosis of the graft due to chronic rejection. Research has shown that Tibetan white pine scion buds require higher concentrations of auxin to activate antifreeze genes, but existing technologies lack targeted optimization of scion bud pretreatment (such as cold acclimation and hormone induction).

[0006] Furthermore, a coordinated protection system against environmental stress in high-altitude regions has yet to be applied to the grafting of Tibetan white pine. While the invention patent CN118020513A improves the survival rate of Korean pine through physical protection (plastic bottles) and potassium fertilizer management, its functionality is limited and does not involve intelligent materials (such as photothermal-responsive binding tape and pH-controlled antimicrobial agents) or dynamic microenvironmental regulation. Grafting Tibetan white pine requires precise maintenance of interface humidity, suppression of UV damage, and simultaneous release of stress-resistant factors. However, existing static moisturizing films and fixed binding tapes make it difficult to achieve multi-parameter coordinated adaptation. Therefore, developing a dynamic adaptation method for grafting Pinus sylvestris var. mongolica onto Tibetan white pine, combining environmentally responsive materials with physiological regulation strategies, is a key approach to breaking through the bottleneck of grafting technology in high-altitude regions. Summary of the Invention

[0007] An object of the present invention is to solve at least the above problems and to provide at least the advantages which will be described hereinafter.

[0008] Another object of the present invention is to provide a method for achieving a high survival rate of Pinus sylvestris grafted onto Pinus tibetica in high-altitude cold regions, which improves the fit between the stock and scion through double-interface adaptation and asymmetric double-wedge scion bud design; the light-responsive intelligent binding strap dynamically adjusts the fixing force and slowly releases antibacterial and healing-promoting drugs; the double-layer protective structure synergistically controls moisture (≥60%), resists UV and is windproof, significantly improving the survival rate of Pinus sylvestris grafted onto Pinus tibetica in high-altitude cold regions.

[0009] In order to achieve these purposes and other advantages according to the present invention, a method for grafting Pinus sylvestris var. mongolica onto Pinus tibetica in high-altitude cold regions with a high survival rate is provided, comprising:

[0010] Step 1: Open two interfaces on the Pinus sylvestris var. mongolica, with the first interface located on the sunny side and cut into an ascending slope, and the second interface located on the shady side and cut into a descending slope, and the first interface and the second interface are connected through an incision;

[0011] Step 2: Select the terminal bud of Tibetan white pine as the scion bud, and cut a double wedge-shaped portion that fits the first interface, the second interface, and the incision;

[0012] Step 3: The double wedge-shaped parts of the scion bud are respectively attached to the double interfaces of the rootstock, and mechanically adapted and fixed using a photothermal responsive shape memory polymer band, wherein the photothermal responsive shape memory polymer band is provided with a penetration hole;

[0013] Step 4: After grafting, a double-layer protective structure is constructed on the outside of the scion bud, wherein the inner layer of the double-layer protective structure is a moisturizing breathable film and the outer layer is an anti-UV windproof net;

[0014] Wherein, a soaked moisture control mass is provided in the moisturizing breathable membrane to maintain the air humidity at the interface at not less than 60% within 20 days.

[0015] like Figure 1 and Figure 2 In the above technical solution, an ascending slope (angle of 30-45°) is cut on the sunny side (south-facing) of the Scots pine rootstock, serving as the first interface 1, reaching down to the cambium. A descending slope (angle of 30-45°) is cut on the shady side (north-facing) as the second interface 2. The two interfaces are connected by a single incision. This dual-bevel design leverages the sun-facing side's light and heat advantage to accelerate callus differentiation, while extending the contact surface on the shady side to buffer frost heave stress. A terminal bud of Tibetan white pine (preferably one-year-old) is selected, and a first wedge-shaped portion 3 and a second wedge-shaped portion 4 are cut, forming a stepped transition at the junction. The first wedge-shaped portion 3 aligns with the sunny first interface 1, utilizing a short, thick structure to resist wind vibration. The second wedge-shaped portion 4 aligns with the shady second interface 2, employing a long, thin design to increase the contact area with the cambium. In particularly windy areas, additional cuts can be added to the first and second interfaces. For example, a spiral interface can be created on the rootstock, and a counter-spiral wedge can be cut on the scion bud to increase torsional strength through the spiral interlocking connection. When the band is wrapped, an initial pressure of 10~15N is applied. When the light intensity is >5000Lux, the hydrogel shrinks after the photothermal layer heats up, reducing the binding force to avoid strangulation when the scion bud expands. When the temperature drops at night, the hydrogel expands and rebounds to maintain a tight fit at the interface. 2) is placed within the moisturizing and breathable membrane to slowly release moisture vapor, maintaining a stable humidity level above 60%, preferably between 60% and 62%. The anti-UV windproof mesh shrinks when wind speeds exceed a threshold, reducing air permeability. The wind speed threshold varies by region, but is generally set between 4 and 8 m / s. In this technical solution, the synergistic effect of the dual interfaces and dual wedges significantly increases the contact area between the cambium and shortens the callus differentiation cycle. The asymmetric structure adapts to temperature differences between the sunny and sunny sides of the rootstock (large diurnal temperature differences occur in high-altitude regions), reducing the risk of interface cracking. The photothermal-responsive dynamic binding intelligently adjusts the binding force, avoiding the "loose-tighten" cycle damage caused by temperature fluctuations in traditional bindings and improving the mechanical stability of the interface. The moisture-control group offsets freeze-thaw fluctuations through water absorption and release cycles, narrowing the humidity fluctuation range. The protective vine has a high UV shielding rate, preventing light damage to the scion bud.

[0016] Preferably, the lengths of the first wedge-shaped portion 3 and the second wedge-shaped portion 4 of the double wedge-shaped portion are 2 cm and 4 cm respectively, and the thickness ratio of the connection between the first wedge-shaped portion 3 and the second wedge-shaped portion 4 is 1:2 (e.g. Figure 2 shown).

[0017] Preferably, the photothermal responsive shape memory polymer bandage includes, from the outside to the inside, a polycaprolactone / carbon nanotube composite photothermal conversion layer, a first poly N-isopropylacrylamide modified thermosensitive hydrogel layer and a drug-loaded porous polylactic acid fiber layer, wherein the carbon nanotube content in the polycaprolactone / carbon nanotube composite photothermal conversion layer is 0.5~1.2wt%, the LCST of the first poly N-isopropylacrylamide modified thermosensitive hydrogel layer is 28°C, and the drug-loaded porous polylactic acid fiber layer is loaded with 10% by mass of nanosilver / desilvered composite antibacterial agent, 5% of indolebutyric acid and β-cyclodextrin. When the inner layer temperature is higher than 28°C, the first poly N-isopropylacrylamide modified thermosensitive hydrogel layer undergoes a volume phase change to promote the sustained release rate of the drug in the drug-loaded porous polylactic acid fiber layer.

[0018] In the above technical solution, polycaprolactone (PCL) and carbon nanotubes (CNTs) are mixed in a mass ratio, wherein the mass content of carbon nanotubes is 0.5~1.2%. For example, polycaprolactone and carbon nanotubes are mixed in a mass ratio of 98.8:1.2, and a thin film with a thickness of 0.5mm is made by melt blending. The photothermal conversion efficiency reaches 85% (heating to 35°C at a light noise intensity of 5000Lux). Under strong light during the day, CNTs absorb light energy and convert it into heat energy, triggering the phase change of the temperature-sensitive layer. The critical solution temperature (LCST) of the first poly N-isopropylacrylamide (PNIPAM) modified hydrogel is adjusted to 28°C through copolymerization modification (such as PNIPAM-co-BMA). When the inner layer temperature is greater than 28°C (precisely matching the temperature fluctuation of -5~25°C in high-altitude cold areas, under the action of the photothermal outer layer, the inner layer temperature is generally 3~6°C higher than the ambient temperature), the first poly N-isopropylacrylamide modified thermosensitive hydrogel layer shrinks (volume decreases) and squeezes the inner layer of drug-loaded fibers to promote drug release. At night, when the inner layer temperature is less than 28°C, the modified hydrogel expands to restore the initial volume, reducing the drug release rate and avoiding Excessive drug consumption; porous polylactic acid fibers are uniformly loaded with nanosilver / desilvered composite antibacterial agent (mass fraction 10%, the mass of nanosilver / desilvered composite antibacterial agent is 10% of the mass of the polylactic acid fiber layer, the mass proportion of nanosilver in the nanosilver / desilvered composite antibacterial agent is 20%, and the mass proportion of desilver in the nanosilver / desilvered composite antibacterial agent is 80%), indolebutyric acid (5%) and β-cyclodextrin to encapsulate drug molecules to extend the sustained-release period (at least 20 days). When the inner layer temperature is greater than 28°C, the pressure generated by the contraction of the first poly (N-isopropylacrylamide) modified thermosensitive hydrogel layer increases the fiber porosity and improves the drug release rate. In the above technical solution, a photothermal-thermosensitive synergistic triggering mechanism (dual signal linkage of light and temperature) is used to achieve a precise match between the drug release rate and the interface healing needs. High temperature during the day accelerates the release of antimicrobial agents, and low temperature at night reduces drug waste, thereby improving the antibacterial efficiency of the interface and shortening the callus differentiation cycle. At the same time, the nanosilver / de-earthed composite antimicrobial agent inhibits common low-temperature pathogens (such as Fusarium) in high-altitude cold areas, indolebutyric acid promotes callus proliferation, and β-cyclodextrin prolongs the drug action period and reduces the frequency of drug application. The thermosensitive layer is modified to adjust the LCST to 28°C to ensure that the temperature difference between day and night in high-altitude cold areas (25°C during the day and -5°C at night. Under the intervention effect of the photothermal outer layer, the temperature of the inner layer can rise to above 28°C) can still respond effectively, avoiding false triggering by low temperature and inability to adapt to the high-altitude cold environment.

[0019] Preferably, the outer layer of the anti-UV windproof net is woven with shape-memory polyurethane fibers. When the ambient wind speed exceeds the wind speed threshold, the mesh aperture automatically shrinks by 40-60%. The inner layer of the moisturizing and breathable membrane uses a polyvinyl alcohol / polyethylene glycol blended polymer membrane as a basic skeleton, and is modified by glutaraldehyde cross-linking to form a three-dimensional grid structure. The inner layer of the moisturizing and breathable membrane is embedded with thermosensitive hydrogel microcapsules. The LCST of the thermosensitive hydrogel microcapsules is 15°C. When the temperature is lower than 15°C, the thermosensitive hydrogel microcapsules release gibberellin A3.

[0020] In the above technical solution, the outer layer of anti-UV windproof net is woven with shape memory polyurethane fiber (SM-PU) with a fiber diameter of 50μm and an initial mesh aperture set to 2~4mm. Thermotropic liquid crystal units (TLC) are embedded in the shape memory polyurethane fiber. When the ambient wind speed exceeds the threshold (generally set to 4~8m / s, which can be fine-tuned according to different regions), the wind pressure triggers the TLC phase change, and the fiber shrinks to reduce the mesh aperture by 40~60%, reducing the air permeability. Polyvinyl alcohol and polyethylene glycol are blended in a mass ratio of 7:3, and 0.5% glutaraldehyde cross-linking agent is added to form a three-dimensional grid membrane with a thickness of 0.1-0.2 mm and a porosity of 60%. Thermosensitive hydrogel microcapsules are embedded in the inner moisturizing and breathable membrane. When the temperature is lower than 15°C, the thermosensitive hydrogel microcapsules release gibberellin A3 to induce antifreeze genes in the scion bud. Because the double-layer protective structure is outside the photothermal responsive shape memory polymer band, its surrounding temperature is lower than the temperature inside the photothermal responsive shape memory polymer band, and the released gibberellin A3 enters the interface through the penetration hole and acts on the scion bud.

[0021] In this technical solution, when wind speed exceeds a threshold, the aperture of the outer UV-resistant windproof mesh shrinks, reducing wind pressure and improving windproof efficiency. The polyvinyl alcohol / polyethylene glycol three-dimensional mesh membrane maintains humidity above 60% with minimal humidity fluctuations, ensuring breathability that matches the respiration needs of the callus. Thermosensitive microcapsules precisely release GA3, maintaining an effective concentration of gibberellin A3 for at least 20 days per single load. This increases the low-temperature survival rate of the scion by at least 50% and accelerates the lignification rate by more than 1.2 times. The SM-PU fiber is cold-resistant to -30°C, extending its lifespan three times that of conventional polyester mesh. The glutaraldehyde cross-linked membrane has a tensile strength of 15 MPa, effectively preventing freeze-thaw cracking.

[0022] Preferably, the gibberellin A3 is encapsulated by a second poly N-isopropylacrylamide modified hydrogel, and the second poly N-isopropylacrylamide modified hydrogel swells and releases gibberellin A3 at low temperatures to improve the low-temperature resistance of the scion bud. The second poly N-isopropylacrylamide modified hydrogel is formed by copolymerizing N-isopropylacrylamide (NIPAM) and butyl methacrylate (BMA) in a molar ratio of 9:1, and its LCST is reduced to about 15°C. The second poly N-isopropylacrylamide (PNIPAM) modified hydrogel was adjusted to have a lower critical solution temperature of 15°C by copolymerization modification, so that it swelled at low temperatures. Gibberellic acid A3 solution (concentration of 0.1 mg / mL) was mixed with β-cyclodextrin to form an inclusion complex to enhance stability. The gibberellin A3 solution was mixed with the PNIPAM prepolymer and emulsified to form oil-in-water droplets. A cross-linking agent was added and ultraviolet light was used to initiate polymerization to form microcapsules with a particle size of 50-100 μm. The mass fraction of gibberellin A3 in the microcapsules was 8-10%. By designing a thermosensitive hydrogel to encapsulate gibberellin A3, the precise release and efficient utilization of antifreeze factors under low temperature stress are achieved, forming a temporal and spatial complementarity with the windproof function of the windbreak net. In the present invention, the PNIPAM hydrogel is non-toxic and degradable, avoiding allelopathic inhibition at the interface. According to the temperature difference in different high-altitude cold areas, the LCST value of the first poly N-isopropylacrylamide-modified hydrogel and the second poly N-isopropylacrylamide-modified hydrogel can be appropriately adjusted on the basis of following the LCST value of the first poly N-isopropylacrylamide-modified hydrogel being greater than the LCST value of the second poly N-isopropylacrylamide-modified hydrogel.

[0023] Preferably, the surface of the anti-UV windproof net is coated with a photochromic nano coating, which is composed of vanadium dioxide and tungsten oxide composite nanowires. When the ultraviolet intensity is greater than the ultraviolet intensity threshold, the refractive index of the coating is automatically lowered, so that the transmittance of the windproof net is reduced by 40~50%. The photochromic nano coating is composed of vanadium dioxide and tungsten oxide composite nanowires, and achieves the function of shielding ultraviolet rays by reflecting and scattering ultraviolet rays. The ultraviolet shielding rate is greater than 90% (wavelength 280~400nm).

[0024] Preferably, the moisture control group includes, from the inside to the outside, a sodium polyacrylate water-absorbent resin compressed core with a thickness of 5:3:5, a spirally wound absorbent cotton fiber and a polylactic acid porous membrane, wherein the water absorption rate of the sodium polyacrylate water-absorbent resin compressed core is 500~800 times, and the sodium polyacrylate water-absorbent resin compressed core releases bound water when the daytime temperature is >5°C, and recaptures condensed water in the polylactic acid porous membrane when the nighttime temperature is <0°C; the diameter of the absorbent cotton fiber is 10~15μm, and the pore size of the polylactic acid porous membrane is 50~100μm.

[0025] In this technical solution, the inner layer of sodium polyacrylate water-absorbent resin is compressed into a core, using sodium polyacrylate particles compressed under high pressure. Its water absorption rate is 500-800 times (i.e., 1g of resin absorbs 500-800g of water). When the daytime temperature is >5°C, the thermal motion of the resin molecular chains is enhanced, releasing bound water. When the nighttime temperature is <0°C, the resin contracts and reabsorbs condensed water within the polylactic acid porous membrane. The middle layer of spirally wound absorbent cotton fibers, with a diameter of 10-15μm and a 60° helix angle, has a 40% interstitial ratio and serves as a moisture conduction channel. The spiral structure guides moisture from the core to the outer polylactic acid porous membrane for uniform diffusion, preventing localized water accumulation or drying. The outer layer of the polylactic acid porous membrane uses a thermally induced phase separation method, with a pore size of 80μm and a porosity of 70%. At night, when the temperature is low, condensation forms on the membrane surface, which then seeps back into the spirally wound absorbent cotton fibers in the middle layer through capillary action and is ultimately absorbed by the compressed core of the sodium polyacrylate absorbent resin in the inner layer. In the above technical solution, the temperature-responsive humidity cycle mechanism is as follows:

[0026] During the day (>5°C), the inner layer of sodium polyacrylate water-absorbing resin compresses the core to release bound water, which is then transferred to the outer layer of polylactic acid porous membrane by the spirally wound absorbent cotton fibers. Water vapor is slowly released through the pores of the porous membrane, maintaining the humidity at 60-62%.

[0027] At night (<0℃), condensed water is generated on the surface of the polylactic acid porous membrane → absorbed by the spirally wound absorbent cotton fibers in the middle layer → adsorbed and stored by the compressed core of the sodium polyacrylate absorbent resin in the inner layer, and the humidity fluctuation is ≤2%.

[0028] In the above technical solution, the inner layer of sodium polyacrylate water-absorbing resin compressed core has a water absorption capacity of 500 to 800 times, which can store the water required at the interface for at least 20 days. Combined with the temperature response release, the humidity is stabilized at 60 to 62%, and condensed water is captured at night to prevent ice expansion from causing cracking of the interface, thereby reducing the frost damage rate. The moisture control group adopts a multi-layer design to achieve gradient management of water. The high water absorption of the inner layer ensures water reserves, the middle layer achieves uniform diffusion of water, and the outer layer controls the release of water vapor and recycles condensed water, with a utilization rate of over 90%. At the same time, the inner layer of sodium polyacrylate water-absorbing resin compressed core has high compressive strength and can support the structure without deformation. The outer layer of polylactic acid porous membrane can withstand low temperatures of -20°C and has a long service life, making it suitable for high-altitude cold areas.

[0029] Preferably, pH-responsive cellulose microspheres are pre-embedded in the spirally wound absorbent cotton fibers, and the pH-responsive cellulose microspheres are loaded with 15% by mass of potassium humate and 5% by mass of trehalose. When the pH at the interface changes to 6.2-6.5 due to callus metabolism, the pH-responsive cellulose microsphere wall material dissolves to release potassium humate to promote callus cell differentiation. At the same time, trehalose and sodium polyacrylate water-absorbing resin compress the moisture in the core to form a hydrogen bond grid, thereby stably controlling the air humidity to above 60%.

[0030] In the above technical solution, pH-responsive cellulose microspheres are pre-embedded in spirally wound absorbent cotton fibers, and the microspheres are loaded with 15% by mass of potassium humate and 5% by mass of trehalose. When the pH at the interface changes to 6.2-6.5 due to callus metabolism, the pH-responsive cellulose microsphere wall material rapidly dissolves and releases the potassium humate and trehalose therein. Through pH-responsive cellulose microspheres, potassium humate can be precisely released at the critical stage of callus metabolism at the interface, that is, when the pH reaches 6.2-6.5, avoiding the adverse effects of premature or late application on cell differentiation, greatly improving the efficiency and quality of callus healing, and precise control can shorten the healing time of callus tissue. The released potassium humate exerts its effect of promoting cell differentiation, accelerating the differentiation process of callus cells, and helping the grafted site heal faster and better. Trehalose and sodium polyacrylate absorbent resin compress the moisture within the core, forming a hydrogen-bonded network. This is due to trehalose's unique chemical structure, which allows it to bind tightly to water. This in turn maintains a stable humidity level above 60%, providing a constant and suitable humidity environment at the grafting interface. The hydrogen-bonded network formed by the trehalose and sodium polyacrylate absorbent resin compresses the moisture within the core, effectively stabilizing humidity. In the complex and changing climates of high-altitude, cold regions, conventional moisturizing methods struggle to maintain a stable humidity level. However, this design ensures that the humidity at the grafting interface remains at or above 60% for 20 days, ensuring a stable humidity level that ensures successful grafting. Experimental results have shown that graft survival rates are indeed higher when using this design compared to those without it.

[0031] In the above technical solution, multiple materials such as pH-responsive cellulose microspheres, potassium humate, trehalose, and sodium polyacrylate absorbent resin compressed core work together to form a complete synergistic system from environmental perception (pH changes) to substance release (potassium humate and trehalose), to promoting healing (potassium humate promotes cell differentiation) and stabilizing the environment (trehalose stabilizes humidity). This system fully utilizes the advantages of each material and greatly improves the overall effect of the grafting method.

[0032] Preferably, an intelligent temperature-control membrane made of phase change material and an aerated gel insulation layer are provided between the moisturizing breathable membrane and the anti-UV windproof mesh, with the intelligent temperature-control membrane positioned adjacent to the moisturizing breathable membrane. The intelligent temperature-control membrane and the aerated gel insulation layer are added between the double-layer protective structure (inner moisturizing breathable membrane, outer anti-UV windproof mesh). The intelligent temperature-control membrane is made of a phase change material, such as paraffin or fatty acids, and adheres tightly to the outer surface of the inner insulating breathable membrane. The phase change material utilizes its latent heat properties to absorb or release heat. When the temperature rises, such as during strong daylight hours, the phase change material absorbs heat and transforms from solid to liquid, suppressing a sudden temperature rise at the interface. When the temperature drops, such as during extremely low temperatures at night, the phase change material transforms from liquid to solid, releasing latent heat and preventing a sudden temperature drop at the interface. The aerogel insulation layer, nestled between the smart temperature-control membrane and the outer windbreak, features a porous structure composed of aerogel materials, such as silica aerogel. This layer traps air to create thermal resistance, reducing the impact of external temperature fluctuations on the interface. This further blocks the exchange of hot and cold air, and, in combination with phase-change materials, allows for daytime and nighttime temperature fluctuations at the interface. Active temperature control overcomes the limitations of passive insulation. Traditional graft protection relies on passive heat blocking by insulation materials, making it difficult to cope with the dramatic temperature swings in high-altitude cold regions. The smart temperature-control membrane utilizes the "heat buffering" function of phase-change materials, combined with the efficient insulation of aerogel, to actively regulate the temperature at the interface, preventing burns from high temperatures or callus cracking from low temperatures. The interface temperature is stabilized within a suitable healing range. This stable temperature maintains cambium cell division activity, shortening callus formation time. The combined design of phase-change materials and aerogel creates a dual barrier of "temperature control and insulation," preventing long-term low-temperature transmission. This barrier is particularly well-suited for the extreme daytime temperature swings experienced in high-altitude cold regions, improving graft survival rates.

[0033] Preferably, the scion bud is placed in a -5°C to 0°C environment for 24 hours before grafting, and a 50-100 μM abscisic acid solution is sprayed simultaneously to induce antifreeze protein gene expression, simulate the low temperature stress environment after grafting in high-altitude cold areas, and induce the scion bud to start the stress resistance physiological mechanism. During the low-temperature acclimation process, a 50-100 μM abscisic acid is sprayed simultaneously, which is absorbed by the leaves or buds to activate the expression of antifreeze protein genes and promote the accumulation of antifreeze substances such as proline and soluble sugars. The pretreated scion bud can adapt to the low temperature environment faster after grafting, reduce the healing delay or failure caused by frost damage, and improve the synchronization of cambium differentiation between the scion and the stock. It is especially suitable for high-altitude cold areas with a short growing season and can effectively extend the healing time window.

[0034] The present invention has at least the following beneficial effects:

[0035] First, the present invention pioneered the use of Pinus sylvestris var. mongolica, a highly stress-resistant and widely distributed western tree, as the rootstock for dwarfing white pine. Experimental results have successfully enabled white pine to bear fruit at least 15 years earlier than the natural growth cycle of 20 years. This significantly shortens the economic payback period for white pine, significantly improving the economic benefits of local forestry and boosting the development of related industries such as food processing using white pine seeds as raw materials. Furthermore, through large-scale dwarfing grafting, it can accelerate its planting and promotion in arid areas of western China, improve the local ecological environment, and achieve a virtuous cycle of ecology and economy.

[0036] Secondly, the method for achieving a high survival rate in grafting Pinus sylvestris var. mongolica onto Pinus tibetica in alpine regions provided by the present invention significantly improves the contact area between the rootstock and scion and the alignment accuracy of the cambium by adopting a dual interface design of an ascending slope on the sunny side and a descending slope on the shady side, combined with a double wedge-shaped structure of the scion bud, thereby promoting efficient callus differentiation, solving the problem of insufficient adhesion of a traditional single interface, and improving the survival rate of Pinus sylvestris var. mongolica grafted onto Pinus tibetica.

[0037] Third, the method provided by the present invention for achieving a high survival rate in grafting Pinus sylvestris var. mongolica onto Pinus thunbergii in alpine regions applies the concept of dynamic intelligent regulation to Pinus sylvestris var. mongolica grafting. By embedding a polycaprolactone / carbon nanotube photothermal layer and a thermosensitive hydrogel-layered drug-loaded fiber layer in the binding strap, the method triggers sustained drug release (nanosilver for antibacterial effects and indolebutyric acid for promoting healing) when the temperature is greater than 15°C. The binding force is adaptively adjusted as the scion bud expands, thereby avoiding mechanical damage, improving antibacterial efficiency, and shortening the interface healing period.

[0038] Fourthly, the method provided by the present invention for achieving a high survival rate in alpine regions by grafting Pinus sylvestris var. mongolica onto Pinus bungeana. The method employs an inner moisturizing and breathable membrane (embedded with thermosensitive hydrogel microcapsules) combined with an outer UV-resistant protective mesh (photochromic coating). The method achieves a stable humidity of ≥60%, a UV shielding rate of >90%, and a mesh size reduction of 40-60% when wind speed exceeds a threshold. This method addresses the issues of traditional plastic bottles, such as mold, fixed light transmittance, and insufficient wind protection, that plague sealed plastic bottles.

[0039] Fifth, in the method for achieving a high survival rate of Pinus sylvestris grafted onto Pinus tibetica in high-altitude cold regions provided by the present invention, the scion buds are pre-placed in an environment of -5°C to 0°C and sprayed with abscisic acid to activate the expression of antifreeze protein genes. Combined with the low-temperature release of gibberellin A3 in the membrane, the stress resistance of the scion buds is enhanced, thereby greatly improving the low-temperature survival rate of Pinus sylvestris grafted onto Pinus tibetica.

[0040] Sixth, the method for achieving a high survival rate of Pinus sylvestris grafted onto Pinus bungeana in high-altitude cold regions provided by the present invention uses a moisture-controlled mass to precisely release healing-promoting ingredients and regulate humidity fluctuations at an interface pH of 6.2-6.5 through a sodium polyacrylate core water absorption / release cycle and pH-responsive microspheres (potassium humate and trehalose), thereby improving the utilization rate of sodium humate and accelerating the callus differentiation rate.

[0041] Seventh, in the method for achieving high survival rate of Pinus sylvestris var. mongolica grafted onto Pinus bungeana in high-altitude areas provided by the present invention, the windbreak net is coated with a vanadium dioxide / tungsten oxide photochromic layer. When the ultraviolet light is greater than the threshold, the transmittance is reduced by 40-50%. The aerated gel layer of the intelligent temperature-control membrane box buffers the temperature difference between day and night, reduces temperature fluctuations at the interface, avoids freeze-thaw damage, and improves lignification efficiency.

[0042] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram of the first interface and the second interface in a technical solution of the present invention;

[0044] Figure 2 This is a schematic structural diagram of the double wedge-shaped portion in another technical solution of the present invention.

[0045] Among them, 1. first interface; 2. second interface; 3. first wedge-shaped portion; 4. second wedge-shaped portion. DETAILED DESCRIPTION

[0046] The present invention will be described in further detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0047] It should be understood that terms such as “having,” “including,” and “comprising” used herein do not prescribe the existence or addition of one or more other elements or combinations thereof.

[0048] Example 1

[0049] Step 1: Cut an ascending slope (at an angle of 45° to the horizontal plane) on the sunny side (south-facing) of the Scots pine rootstock to a depth of the cambium layer, and cut a descending slope (at an angle of 45° to the horizontal plane) on the shady side (north-facing) to a depth of the cambium layer, and connect the first interface and the second interface through an incision;

[0050] Step 2: Cut the one-year-old terminal bud of Tibetan white pine as the scion bud, and cut the asymmetrical double wedge-shaped part. Figure 2 As shown, the first wedge is 2 cm long and the second wedge is 4 cm long;

[0051] Step three, fit the double wedge-shaped part of the scion bud to the double interface of the stock, and fix it with a photothermal responsive shape memory polymer bandage, wherein the photothermal responsive shape memory polymer bandage includes a polycaprolactone / carbon nanotube composite photothermal conversion layer, a first poly N-isopropylacrylamide modified thermosensitive hydrogel layer and a drug-loaded porous polylactic acid fiber layer from the outside to the inside, wherein the carbon nanotube content in the polycaprolactone / carbon nanotube composite photothermal conversion layer is 1.2wt%, the LCST of the first poly N-isopropylacrylamide modified thermosensitive hydrogel layer is 28°C, and the drug-loaded porous polylactic acid fiber layer contains 10% by mass of nanosilver / de-earthed composite antibacterial agent, 5% of indolebutyric acid and β-cyclodextrin;

[0052] Step 4: Construct a double-layer protective structure. The outer layer of the anti-UV windproof net is woven with shape-memory polyurethane fiber. When the ambient wind speed exceeds the wind speed threshold, the mesh aperture automatically shrinks by 60%; the inner layer of the moisturizing and breathable membrane is a polyvinyl alcohol / polyethylene glycol blended polymer membrane as the basic skeleton, and is modified by glutaraldehyde cross-linking to form a three-dimensional grid structure. The inner layer of the moisturizing and breathable membrane is embedded with a second poly N-isopropylacrylamide modified hydrogel microcapsule. The LCST of the second poly N-isopropylacrylamide modified hydrogel microcapsule is 15°C. When the temperature is lower than 15°C, the thermosensitive hydrogel microcapsule releases gibberellin A3. A soaked moisture control group is provided in the moisturizing and breathable membrane. The moisture control group includes, from the inside to the outside, a sodium polyacrylate water-absorbent resin compressed core with a thickness of 5:3:5, a spirally wound absorbent cotton fiber and a polylactic acid porous membrane. The water absorption rate of the sodium polyacrylate water-absorbent resin compressed core is 800 times, and the sodium polyacrylate water-absorbent resin compressed core releases bound water when the daytime temperature is >5°C, and recaptures condensed water in the polylactic acid porous membrane when the nighttime temperature is <0°C; the diameter of the absorbent cotton fiber is 15μm, and the pore size of the polylactic acid porous membrane is 100μm.

[0053] Example 2

[0054] Step 1: Same as Example 1;

[0055] Step 2: Same as Example 1;

[0056] Step 3: Same as Example 1;

[0057] Step 4. Based on Example 1, pH-responsive cellulose microspheres are pre-embedded in the spirally wound absorbent cotton fibers. The pH-responsive cellulose microspheres are loaded with 15% by mass of potassium humate and 5% by mass of trehalose. When the pH at the interface changes to 6.5 due to callus metabolism, the pH-responsive cellulose microsphere wall material dissolves and releases potassium humate to promote callus cell differentiation. At the same time, trehalose and sodium polyacrylate water-absorbing resin compress the moisture in the core to form a hydrogen bond grid, thereby stably controlling the air humidity at above 60%.

[0058] Example 3

[0059] Step 1: Same as Example 1;

[0060] Step 2: Same as Example 1;

[0061] Step 3: Same as Example 1;

[0062] Step 4: Based on Example 1, an intelligent temperature control membrane made of phase change material and an aerated gel insulation layer are further provided between the moisturizing breathable membrane and the anti-UV windproof net, and the intelligent temperature control membrane is provided close to the moisturizing breathable membrane.

[0063] Example 4

[0064] Step 1: Same as Example 1;

[0065] Step 2: Based on Example 1, the scion bud is placed in a -5°C to 0°C environment for 24 hours before grafting, and is simultaneously sprayed with a 100 μM abscisic acid solution to induce antifreeze protein gene expression;

[0066] Step 3: Same as Example 1;

[0067] Step 4: Same as Example 1.

[0068] Comparative Example 1

[0069] A single interface (single slope on the sunny side) is adopted, the scion bud is a single wedge-shaped portion, and the rest is the same as in Example 1.

[0070] Comparative Example 2

[0071] Use ordinary straps for fixing, and the rest is the same as in Example 1.

[0072] Comparative Example 3

[0073] A common protective net is used, and no moisture control group is provided. Other aspects are the same as those of Example 1.

[0074] Comparative Example 4

[0075] A double-layer protective structure is adopted, but no moisture control group is provided, and the rest is the same as in Example 1.

[0076] The callus differentiation cycle, grafting survival rate, interface colony count, UV shielding rate, effective healing window length and humidity fluctuation of Examples 1 to 4 and Comparative Examples 1 to 4 were investigated, and the results are shown in Table 1.

[0077] Table 1 Data of Pinus sylvestris grafted onto Pinus thunbergii

[0078]

[0079] As can be seen from Table 1, Example 1, which uses a dual interface + dual wedges + smart bands + humidity control group, achieved a callus differentiation cycle of 15 days, a 47% reduction compared to the traditional single interface (Comparative Example 1, 22 days). This is because the dual interface increases the cambium contact area, and the humidity control group stabilizes humidity and promotes cell division. Example 2, based on Example 1, adds pH-responsive microspheres, achieving a callus differentiation cycle of 12 days. The precise release of sodium humate accelerates callus differentiation, resulting in a 20% reduction compared to Example 1. Comparative Example 1, which uses a single interface and single wedge grafting method, has the longest callus differentiation cycle. Due to the small cambium contact area, stress concentration at the interface can easily lead to cracking.

[0080] It can also be seen from Table 1 that Example 3 adds an intelligent temperature control film and an aerated gel insulation layer to Example 1, and its graft survival rate can reach 98%. The use of active temperature control to reduce temperature difference damage increases the survival rate by 7.7% compared with Example 1. However, Comparative Example 3 uses ordinary protective nets and no moisture control group, and its graft survival rate is only 75%. This is because UV burns, excessive wind speeds, and large humidity fluctuations lead to the death of the scion. Example 1 uses a photothermal responsive shape memory polymer bandage, and its interface colony count is 80 CFU / cm 2 , the nano silver antibacterial agent effectively inhibited the low temperature pathogens, compared with the comparative example 2 (using ordinary bandage, 120 CFU / cm 2 ) was reduced by 50%. This is because in Comparative Example 2, there was no sustained-release drug, resulting in a high bacterial count and a high risk of causing interface infection. The UV shielding rates of Examples 1-4 were ≥90%, and the UV windbreak nets effectively shielded the scion buds from UV damage. However, in Comparative Example 3, the UV shielding rate of the conventional protective net was only 50%, making the scion buds susceptible to UV burns and reducing the survival rate.

[0081] Table 1 also shows that Example 4, which pretreated the scion bud, had an effective healing window of 42 days. The abscisic acid-induced antifreeze protein extended the low-temperature acclimatization period, a 28% increase compared to Example 1 (35-day effective healing window). Comparative Example 1, however, had an effective healing window of only 23 days, owing to poor frost resistance and stagnant healing at low temperatures. Humidity fluctuations in Examples 1-4 were all below 2%, with Example 2 experiencing a 1.5% fluctuation. The trehalose hydrogen bonding network stabilized humidity, further reducing humidity fluctuations compared to Example 1 (2%). Comparative Examples 3 and 4, however, both experienced humidity fluctuations of ≥5%, lacking a moisture control or pH-responsive mechanism, making them susceptible to interface damage due to desiccation or condensation.

[0082] In summary, the present invention adopts a double-interface + double-wedge grafting method to directly increase the contact area formed, shorten the callus differentiation cycle, and increase the survival rate by 30% (70%→91%) compared with a single interface; the present invention adopts a photothermal responsive shape memory polymer bandage + humidity control group structure, which effectively reduces the number of interface colonies and reduces humidity fluctuations through drug sustained release and precise humidity control; the present invention also actively responds to high-altitude temperature differences and low-temperature stress through temperature control membrane + scion pretreatment, thereby extending the effective healing window and further improving the survival rate of grafting.

[0083] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A method for achieving high survival rate of Pinus sylvestris var. mongolica grafted onto Pinus bungeana in high-altitude cold regions, characterized in that: include: Step 1: Open two interfaces on the Pinus sylvestris var. mongolica, with the first interface located on the sunny side and cut into an ascending slope, and the second interface located on the shady side and cut into a descending slope, and the first interface and the second interface are connected through an incision; Step 2: Select the terminal bud of Tibetan white pine as the scion bud, and cut a double wedge-shaped portion that fits the first interface, the second interface, and the incision; Step 3: The double wedge-shaped parts of the scion bud are respectively attached to the double interfaces of the rootstock, and mechanically adapted and fixed using a photothermal responsive shape memory polymer band, wherein the photothermal responsive shape memory polymer band is provided with a penetration hole; Step 4: After grafting, a double-layer protective structure is constructed on the outside of the scion bud, wherein the inner layer of the double-layer protective structure is a moisturizing breathable film and the outer layer is an anti-UV windproof net; Wherein, a wetted moisture control mass is provided in the moisturizing breathable membrane to maintain the air humidity at the interface at not less than 60% within 20 days; The photothermal responsive shape memory polymer bandage includes, from the outside to the inside, a polycaprolactone / carbon nanotube composite photothermal conversion layer, a first poly N-isopropylacrylamide modified thermosensitive hydrogel layer, and a drug-loaded porous polylactic acid fiber layer, wherein the carbon nanotube content in the polycaprolactone / carbon nanotube composite photothermal conversion layer is 0.5-1.2wt%, the LCST of the first poly N-isopropylacrylamide modified thermosensitive hydrogel layer is 28°C, and the drug-loaded porous polylactic acid fiber layer is loaded with 10% by mass of a nanosilver / desilvered composite antibacterial agent, 5% of indolebutyric acid and β-cyclodextrin. When the temperature of the inner layer is higher than 28°C, the first poly N-isopropylacrylamide modified thermosensitive hydrogel layer undergoes a volume phase change, which promotes the sustained release rate of the drug in the drug-loaded porous polylactic acid fiber layer. The outer layer of the anti-UV windproof mesh is woven from shape-memory polyurethane fibers. When the ambient wind speed exceeds the wind speed threshold, the mesh aperture automatically shrinks by 40-60%. The inner layer of the moisturizing and breathable membrane uses a polyvinyl alcohol / polyethylene glycol blended polymer membrane as the basic skeleton, modified by glutaraldehyde cross-linking to form a three-dimensional grid structure. The inner layer of the moisturizing and breathable membrane is embedded with thermosensitive hydrogel microcapsules. The LCST of the thermosensitive hydrogel microcapsules is 15°C. When the temperature is below 15°C, the thermosensitive hydrogel microcapsules release gibberellin A3. The moisture control group includes, from the inside to the outside, a compressed core of sodium polyacrylate water-absorbent resin with a thickness of 5:3:5, spirally wound absorbent cotton fibers, and a polylactic acid porous membrane, wherein the water absorption rate of the compressed core of the sodium polyacrylate water-absorbent resin is 500 to 800 times, and the compressed core of the sodium polyacrylate water-absorbent resin releases bound water when the daytime temperature is >5°C, and recaptures condensed water in the polylactic acid porous membrane when the nighttime temperature is <0°C; the diameter of the absorbent cotton fibers is 10 to 15 μm, and the pore size of the polylactic acid porous membrane is 50 to 100 μm.

2. The method for high survival rate of Pinus sylvestris var. mongolica grafted onto Pinus bungeana in alpine areas as claimed in claim 1, wherein: The lengths of the first wedge-shaped portion and the second wedge-shaped portion of the double wedge-shaped portion are 2 cm and 4 cm respectively, and the thickness ratio of the connection between the first wedge-shaped portion and the second wedge-shaped portion is 1:

2.

3. The method for high survival rate of Pinus sylvestris var. mongolica grafted onto Pinus bungeana in alpine areas as claimed in claim 1, characterized in that: The gibberellin A3 is wrapped by a second poly N-isopropylacrylamide modified hydrogel, and the second poly N-isopropylacrylamide modified hydrogel swells at low temperatures to release gibberellin A3 to improve the low temperature resistance of the scion bud.

4. The method for high survival rate of Pinus sylvestris var. mongolica grafted onto Pinus bungeana in alpine areas as claimed in claim 1, wherein: The surface of the anti-UV windproof net is coated with a photochromic nano coating, which is composed of vanadium dioxide and tungsten oxide composite nanowires. When the ultraviolet intensity is greater than the ultraviolet intensity threshold, the refractive index of the coating is automatically lowered, reducing the light transmittance of the windproof net by 40-50%.

5. The method for high survival rate of Pinus sylvestris var. mongolica grafted onto Pinus bungeana in high-altitude cold regions according to claim 1, characterized in that: pH-responsive cellulose microspheres are pre-embedded in the spirally wound absorbent cotton fibers. The pH-responsive cellulose microspheres are loaded with 15% by mass of potassium humate and 5% by mass of trehalose. When the pH at the interface changes to 6.2-6.5 due to callus metabolism, the wall material of the pH-responsive cellulose microspheres dissolves to release potassium humate to promote callus cell differentiation. At the same time, trehalose and sodium polyacrylate water-absorbing resin compress moisture in the core to form a hydrogen bond grid, thereby stably regulating the air humidity to above 60%.

6. The method for high survival rate of Pinus sylvestris var. mongolica grafted onto Pinus bungeana in high-altitude cold regions according to claim 1, characterized in that: An intelligent temperature control membrane made of phase change material and an aerated gel insulation layer are also provided between the moisturizing breathable membrane and the anti-UV windproof net. The intelligent temperature control membrane is provided close to the moisturizing breathable membrane.

7. The method for high survival rate of Pinus sylvestris var. mongolica grafted onto Pinus bungeana in high-altitude cold regions as claimed in claim 1, characterized in that: The scion bud is placed in a -5°C to 0°C environment for 24 hours before grafting, and is simultaneously sprayed with an abscisic acid solution with a concentration of 50 to 100 μM to induce the expression of the antifreeze protein gene.

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