Efficient strawberry seedling cultivation method

Abstract

The invention relates to the technical field of agricultural planting, and particularly discloses an efficient strawberry seedling cultivation method. Comprising the following steps: S1, performing steam sterilization on a composite seedling culture substrate, and mixing with a microbial fermentation product; s2, a seedling culture container is filled with the pretreated substrate, and a seedling culture bed body is obtained; s3, strawberry stolon stem tips are collected, stem tip meristem is stripped under the sterile condition, and dark culture is carried out; s4, the cutting slips subjected to detoxification pretreatment are cut into a seedling raising bed body; s5, inducing directional development of root systems of the symbiotic cutting seedlings to obtain root strengthening seedlings; s6, after the root systems of the strong-root seedlings are fully distributed in the seedling culture container, flower bud differentiation is induced, and grown seedlings are obtained. The cultivation method provided by the invention can be used for factory-like and standardized seedling production of strawberries, and is especially suitable for large-scale planting with relatively high requirements on seedling health degree, uniformity and early yield; the method has the advantages of being high in integration level, high in operability and short in seedling period.

Description

Technical Field

[0001] This application relates to the field of agricultural planting technology, and more specifically, it relates to a method for efficient strawberry seedling cultivation. Background Technology

[0002] The application of agricultural planting technology spans the entire process from soil management to harvesting. By integrating modern biotechnology, the Internet of Things, intelligent equipment, and ecological concepts, it has achieved a systematic upgrade of traditional farming methods. In practice, precision irrigation and soil testing-based fertilization rely on sensors and big data analysis to deliver water and fertilizer directly to the crop roots, improving resource utilization. Greenhouses and plant factories utilize environmental control technologies to break through seasonal and geographical limitations, ensuring a stable year-round supply of agricultural products. Drones and intelligent agricultural machinery undertake sowing, plant protection, and monitoring tasks, multiplying operational efficiency. The comprehensive application of these technologies not only increases yield per unit area and the quality of agricultural products, meeting the needs of a growing population, but also alleviates the conflict between agricultural production and the ecological environment by reducing the overuse of chemical fertilizers and pesticides, protecting soil health and water resources.

[0003] Related agricultural planting involves soil cultivation and conventional propagation methods, such as direct cuttings or seed sowing. However, these methods often result in slow propagation speed, susceptibility to viruses and pests, uneven seedling growth, and flower bud differentiation that depends on natural seasonal conditions. Consequently, strawberry seedling production cycles are long, quality is unstable, and flowering and fruiting are delayed, making it difficult to meet the demands of modern agriculture for efficient, sterile, and early-maturing cultivation. Summary of the Invention

[0004] To address the problems of long production cycles, unstable quality, and delayed flowering and fruiting of strawberry seedlings caused by direct cuttings or seed sowing in related agricultural planting, this application provides a method for efficient strawberry seedling cultivation.

[0005] This application provides a method for efficient strawberry seedling cultivation, employing the following technical solution: A method for efficient strawberry seedling cultivation includes the following steps: S1. After steam sterilization, the composite seedling substrate is mixed with microbial fermentation products and aerobic fermentation is induced to obtain the pretreated substrate. S2. Fill the pretreated substrate into the seedling container and inject a complexed trace element solution into it for pre-wetting to obtain the seedling bed. S3. Collect strawberry runner tips, peel off the meristems of the stolons under sterile conditions, and place them in an induction medium containing melatonin and ascorbic acid for dark culture to obtain virus-free pretreated cuttings; S4. Insert the virus-free pretreated cuttings into the seedbed and fill the cutting opening with a water-retaining fungal symbiotic agent to obtain symbiotic cuttings. S5. Photoperiod regulation and rhizosphere temperature gradient stimulation are applied to the symbiotic cuttings to induce directional root development and obtain robust root seedlings. S6. After the roots of the strong-rooted seedlings have filled the seedling container, they are subjected to gradient drought stress and nitrogen reduction and phosphorus increase treatment to induce flower bud differentiation and obtain seedlings that can be planted.

[0006] By adopting the above technical solution, this method integrates a series of technologies such as substrate bio-fermentation activation, shoot tip detoxification and rapid propagation, mycorrhizal symbiosis, photothermal synergistic regulation and stress-induced flowering, forming a complete seedling system from substrate treatment, cutting preparation, cutting symbiosis, root promotion and seedling strengthening to flower bud induction. Therefore, it can obtain rapid, sterile and robust propagation of strawberry seedlings, complete flower bud physiological differentiation in advance, and finally obtain uniform seedlings with stress resistance that can flower and bear fruit earlier after transplanting.

[0007] Preferably, in step S1, the composite seedling substrate is composed of coconut coir, peat, and vermiculite mixed in a mass ratio of (5-7):(2-3):(1-2); the steam sterilization temperature is 90-110℃, the pressure is 0.05-0.1MPa, and the time is 40-60min; the microbial fermentation product is corn cob powder containing Bacillus subtilis and Trichoderma, and its addition amount is 10%-15% of the volume of the composite seedling substrate; the aerobic fermentation induction time is 5-7 days, during which the pile is turned over to maintain the temperature at 45-55℃.

[0008] By adopting the above technical solution, a composite substrate with stable structure, air permeability, and water retention capacity was constructed by using a specific ratio of coconut coir, peat, and vermiculite. Subsequently, the substrate was treated with steam at 90-110°C and 0.05-0.1 MPa for 40-60 minutes. This process killed pathogens and weed seeds while preserving the organic structure of the substrate. Then, corn cob powder containing Bacillus subtilis and Trichoderma was inoculated as a fermentation primer. During the aerobic fermentation process of 5-7 days, the core temperature of the pile was controlled at 45-55°C by turning the pile. This condition is conducive to the colonization and proliferation of fermenting microorganisms and initiates the degradation and humification of coarse fibers in the substrate. Therefore, a preliminarily fermented, active seedling substrate rich in beneficial microbial communities, with optimized physicochemical properties and low pathogen risk was obtained, laying a physical and biological foundation for subsequent strawberry root development.

[0009] Preferably, in step S2, the complexed trace element solution contains EDTA-iron, EDTA-zinc, and boric acid, with mass concentrations of 0.1%–0.2%, 0.05%–0.1%, and 0.02%–0.05%, respectively; the pre-wetting process controls the substrate moisture content of the seedling bed to 55%–65%, and adjusts the EC value of the substrate to 0.4–0.6 mS / cm, with a porosity of over 60%.

[0010] By adopting the above technical solution, the use of ethylenediaminetetraacetic acid (EDTA) to complex iron and zinc elements ensures the stability and effectiveness of these trace elements in the substrate environment. This is combined with boric acid to prepare a solution. After the substrate is filled into the container, it is pre-moistened with this solution, uniformly providing the trace elements such as iron, zinc, and boron required for the early growth of seedlings. The initial moisture content of the substrate is adjusted to the range of 55%-65%, while the electrical conductivity of the substrate is controlled at 0.4-0.6 mS / cm, and the porosity of the substrate is maintained at over 60%. Therefore, a seedling rhizosphere environment with a balanced ratio of water, nutrients, and air, rich in easily absorbed trace elements, is obtained, creating conditions for the early absorption of nutrients by subsequent cuttings and scions.

[0011] Preferably, in step S3, the stripping of the shoot tip meristem involves stripping the shoot tip growth point with a size of 0.2–0.5 mm; the induction medium is based on MS medium, with the addition of 0.5–1.0 mg / L of 6-benzyl adenine, 0.01–0.05 mg / L of naphthaleneacetic acid, 0.1–0.5 mg / L of melatonin, and 10–20 mg / L of ascorbic acid; the dark culture temperature is 22–26 °C, the humidity is 70%–80%, and the culture time is 7–10 days.

[0012] By employing the above-mentioned technical solution, using 0.2-0.5 mm shoot tip meristems as explants, these parts are typically virus-free or have already been devirulent. Subsequently, they are inoculated into MS medium supplemented with a specific concentration of 6-benzyladenine and naphthaleneacetic acid, a hormone combination that initiates cell division and growth. The added melatonin and ascorbic acid work synergistically under dark culture conditions to reduce oxidative damage and phenolic toxicity to the explants. Cultured in a stable dark environment at 22-26°C and 70%-80% humidity for 7-10 days, this process avoids chloroplast differentiation, allowing nutrients to be used for cell activation and initial growth. Therefore, a miniature cutting primordium that has initiated growth, is physiologically active, and possesses virus-free potential is obtained, providing material for subsequent adaptation and survival after transplanting and cutting.

[0013] Preferably, in step S4, the water-retaining fungal symbiotic agent is a mixture of mycorrhizal fungal agent, superabsorbent resin and wood ash in a mass ratio of (1-2):(5-8):(2-3); the filling is to apply the water-retaining fungal symbiotic agent in dry powder form around the cutting after the cutting is covered with soil, with a dosage of 0.5-1.0g per cutting.

[0014] By adopting the above technical solution, a compound combination of mycorrhizal fungi, superabsorbent resin, and wood ash is used. After cutting, this mixture is applied around the cutting site. The mycorrhizal fungi infect the newly formed strawberry roots, establishing a symbiotic relationship and expanding the root absorption range. The superabsorbent resin adsorbs and releases moisture near the cutting site, providing a stable moisture microenvironment in the early stages of root formation. The wood ash provides readily available potassium and regulates the local pH, promoting wound healing and inhibiting soil-borne diseases. The three work synergistically to form a functional microzone at the cutting site with an application rate of 0.5-1.0g per plant. Therefore, a local symbiotic protection system is obtained that can retain water, promote root growth, prevent disease, and provide nutritional support during the cutting stage. This improves the survival rate and early planting speed of virus-free pretreated cuttings when transplanted to a non-sterile substrate environment.

[0015] Preferably, in step S5, the photoperiod regulation is as follows: within 1 to 10 days after cutting, the cutting is treated with a red light to far-red light ratio of 1:1 to 2:1, and the light intensity is 100 to 150 μmol·m⁻¹. -2 ·s -1 The daily light exposure time is 14 to 16 hours; the rhizosphere temperature gradient stimulation is achieved by maintaining the diurnal temperature difference of the substrate at 8 to 12°C through water bath circulation, with the daytime temperature at 22 to 25°C and the nighttime temperature at 10 to 14°C.

[0016] By adopting the above technical solution, during the rooting period after cuttings, a specific ratio of red and far-red light is used for 14-16 hours of long-day treatment daily. This light quality and photoperiod regulate the phytochrome system, promoting the synthesis and transport of endogenous auxin and inhibiting gibberellin activity, thereby inducing the occurrence and development of adventitious roots; combined with 100-150 μmol·m -2 ·s -1 The light intensity is sufficient to meet the photosynthetic requirements; at the same time, a diurnal temperature difference of 8-12°C is formed by controlling the rhizosphere temperature. During the day, 22-25°C promotes cell division and elongation, while at night, 10-14°C increases the accumulation of carbohydrates in the roots. Therefore, the synergistic regulation of the rooting process by light signals and temperature gradient signals stimulates the occurrence, growth and development of the root system, providing an environmental driving force for cultivating strong-rooted seedlings.

[0017] Preferably, in step S5, during the process of inducing the directional development of the root system, a root-promoting agent is applied. The root-promoting agent is prepared by potassium humate, sodium nitroprusside and calcium nitrate in a mass ratio of (10-15):(1-2):(5-8), diluted 800-1000 times, and then applied to the roots every 5-7 days.

[0018] By adopting the above technical solution, and in conjunction with light and temperature environment control, a root-promoting agent composed of potassium humate, sodium nitroprusside, and calcium nitrate is applied. Potassium humate acts as a biostimulant, improving the rhizosphere microenvironment and activating nutrients; sodium nitroprusside acts as a nitric oxide donor, participating in the regulation of root growth, development, and morphogenesis; and calcium nitrate provides nitrate nitrogen and calcium ions, with calcium being essential for the activity of root tip meristems and cell wall formation. The three components are diluted and applied to the roots in a specific ratio, replenished every 5-7 days. Therefore, from the aspects of chemical signals, nutrient supply, and soil environment improvement, the root development of strawberry cuttings is physiologically enhanced, forming a guarantee with environmental control, accelerating root growth, and increasing root vitality and absorption area.

[0019] Preferably, in step S6, the gradient drought stress is: gradually reducing the substrate moisture content from 60%–65% to 30%–35%, with a daily decrease of 5%–8%, and maintaining each moisture content gradient for 2–3 days; the nitrogen reduction and phosphorus increase treatment is: stopping the application of nitrogen fertilizer, and foliar spraying with a 0.2%–0.3% potassium dihydrogen phosphate solution, once every 3 days, for 3–4 consecutive times.

[0020] By adopting the above technical solution, after root development, a gradient drought stress is applied by gradually reducing the substrate moisture content by 5%-8% daily, allowing the plant to experience a gradual water shortage process. Each moisture content plateau is maintained for 2-3 days to induce an adaptive physiological response. This process increases the level of stress hormones such as abscisic acid in the plant, which becomes a signal to initiate flower bud differentiation. Simultaneously, a nutrient regulation of reducing nitrogen and increasing phosphorus is implemented. Nitrogen supply is stopped to slow down vegetative growth, while foliar spraying with 0.2%-0.3% potassium dihydrogen phosphate helps with the synthesis of energy substances and the transport of carbohydrates to reproductive organs. Therefore, through the synergy of water stress signals and carbon and nitrogen nutrient metabolism pathways, the physiological growth center of strawberry seedlings is shifted from vegetative growth to reproductive development, initiating the flower bud differentiation process.

[0021] Preferably, in step S6, the process of inducing flower bud differentiation also includes a low-temperature induction treatment: the ambient temperature is reduced from 18°C ​​to 8°C at a rate of 2°C per day, and maintained at 8°C for 7–10 days, while the daily light duration is controlled to be 8–10 hours and the light intensity to be 80–120 μmol·m⁻². -2 ·s -1 .

[0022] By adopting the above technical solution, while implementing water and nutrient regulation, a low-temperature short-day induction treatment is applied; the ambient temperature is reduced from 18°C ​​to 8°C at a rate of 2°C per day and maintained at 8°C for 7-10 days, while the photoperiod is shortened to 8-10 h / d, and 80-120 μmol·m⁻²·m⁻²·g⁻¹ ... -2 ·s -1The light intensity; the low temperature and short day conditions simulate the natural ecological conditions required for strawberry flower bud differentiation. The low temperature and short day signals work together to enhance the physiological and gene expression regulation of the plant's transition from vegetative growth to reproductive growth. Therefore, multiple environmental factors are synchronously induced to induce strawberry flower bud differentiation, ensuring the synchronicity and ratio of the flower bud differentiation process under controllable conditions, so that the seedlings have the potential to flower.

[0023] Preferably, in step S6, the criteria for obtaining seedlings suitable for transplanting are: seedling age 45–60 days, root activity ≥200 μg·g -1 ·h -1 The rhizome is ≥0.8cm thick, has 4-5 unfolded leaves, and the flower bud differentiation rate reaches over 80%.

[0024] By adopting the above technical solution, this method defines seedling standards covering seedling age, physiological activity, morphological indicators, and developmental stage; a seedling age of 45-60 days reflects the speed of this seedling system; and root activity is not less than 200 μg·g⁻¹. -1 ·h -1 This reflects the metabolic and absorption capacity of the root system; a rootstock thickness of not less than 0.8 cm is a morphological marker of abundant nutrient storage and stress resistance in the plant; having 4-5 unfolded leaves indicates robust above-ground vegetative tissue; and a flower bud differentiation rate of over 80% is a biological marker of this technical scheme's ability to induce reproductive development and achieve early-maturing cultivation goals. Therefore, the resulting seedlings are robust, physiologically active, and have completed flower bud physiological differentiation, ensuring successful recovery and flowering after transplanting, thus laying the foundation for high yield and early maturity.

[0025] In summary, this application has the following beneficial effects: 1. Because this application adopts a process from composite substrate bio-fermentation activation, shoot tip detoxification and rapid propagation, mycorrhizal symbiosis establishment, light and temperature synergistic root promotion to stress-induced flowering, the previous step provides a suitable biological or physicochemical environment for the next step, thereby achieving rapid and sterile propagation of strawberry seedlings and completing the physiological differentiation of flower buds in advance, thus achieving the effect of producing uniform and consistent seedlings that can flower and bear fruit earlier.

[0026] 2. Because this application uses a composite of coconut coir, peat and vermiculite in the substrate preparation, and then performs steam sterilization and aerobic fermentation induction with the addition of specific microbial fermentation products in sequence, the steam sterilization not only removes pathogens but also provides an environment for subsequent beneficial microbial fermentation. At the same time, the Bacillus subtilis and Trichoderma introduced can quickly colonize and initiate the humification improvement of the substrate during the aerobic fermentation process, resulting in an active seedling substrate that has a supporting structure, is rich in active beneficial bacteria and has a low pathogen risk, providing a stable physical support and microecological foundation for the subsequent root development of cuttings.

[0027] 3. The method of this application involves combining cuttings obtained from virus-free culture of shoot tip meristem with a water-retaining fungal symbiotic agent containing mycorrhizal fungi, superabsorbent resin, and wood ash during cutting propagation. Since the virus-free cuttings are pure but have weak resistance, the superabsorbent resin in the symbiotic agent can provide local moisture buffering, while the wood ash regulates the micro-pH and inhibits bacteria, and the mycorrhizal fungi can gradually infect the new roots to establish a symbiotic relationship. The three work together to form a multi-layered protection of physical water retention, chemical regulation, and biological symbiosis in the early stage of cutting transplantation. Therefore, a high survival rate and rapid mycorrhizal establishment effect are achieved when virus-free seedlings transition to a non-sterile cultivation environment.

[0028] 4. The method of this application combines photoperiod regulation, rhizosphere diurnal temperature gradient stimulation, and root irrigation with root-promoting agents during the root-promoting stage. Appropriate light quality and photoperiod regulate endogenous hormones to promote root growth through phytochrome, diurnal temperature difference promotes carbohydrate accumulation in the roots, and sodium nitroprusside releases nitric oxide signaling molecules, potassium humate improves the rhizosphere environment, and calcium nitrate provides nutrients and structural components. These factors synergistically enhance the rooting process from both environmental signal transduction and rhizosphere nutrient chemical environment aspects, thus achieving a targeted and efficient effect on root development, growth, and robustness.

[0029] 5. In the pre-seedling stage, this application synergistically applies gradient drought stress, nitrogen-reduced and phosphorus-increased foliar nutrient management, and low-temperature short-day treatment. The gradually decreasing soil moisture induces stress signals such as abscisic acid, while nitrogen-reduced and phosphorus-increased nutrient management regulates carbon and nitrogen metabolic flow. Continuous low-temperature short-day treatment provides the environmental cycle signals required for flowering. These three stimulation signals, which are respectively derived from water, nutrients, and light and temperature, jointly strengthen the physiological and molecular regulatory network of the transition from vegetative growth to reproductive development in the plant. Therefore, a high ratio and good synchronization of flower bud differentiation are obtained, ensuring that the seedlings have uniform early flowering potential. Attached Figure Description

[0030] Figure 1 This is a flowchart of a high-efficiency strawberry seedling cultivation method proposed in this application. Detailed Implementation

[0031] The present application will be further described in detail below with reference to the accompanying drawings and embodiments.

[0032] Technical concept: Related agricultural planting involves soil cultivation and conventional propagation methods, such as direct cuttings or seed sowing. However, these methods often result in slow propagation speed, susceptibility to viruses and pests, uneven seedling growth, and flower bud differentiation that depends on natural seasonal conditions. Consequently, strawberry seedling production cycles are long, quality is unstable, and flowering and fruiting are delayed, making it difficult to meet the demands of modern agriculture for efficient, sterile, and early-maturing cultivation.

[0033] This application discloses a method for efficient strawberry seedling cultivation. It includes the following steps: S1, sterilizing a composite seedling substrate by steam and then mixing it with microbial fermentation products; S2, filling the pretreated substrate into a seedling container to obtain a seedling bed; S3, collecting strawberry stolons, separating the meristematic tissue under aseptic conditions, and conducting dark culture; S4, inserting virus-free pretreated cuttings into the seedling bed; S5, inducing directional root development in the symbiotic cuttings to obtain robust-rooted seedlings; S6, after the roots of the robust-rooted seedlings have filled the seedling container, inducing flower bud differentiation to obtain mature seedlings.

[0034] This application adopts a process from composite substrate bio-fermentation activation, shoot tip detoxification and rapid propagation, mycorrhizal symbiosis establishment, light and temperature synergistic root promotion to stress-induced flowering. The preceding steps provide a suitable biological or physicochemical environment for the subsequent steps, thereby enabling rapid and sterile propagation of strawberry seedlings and early completion of flower bud physiological differentiation, thus achieving the effect of uniform production and early flowering and fruiting.

[0035] Example 1: This example provides a method for efficient strawberry seedling cultivation, which includes the following steps: S1. After steam sterilization, the composite seedling substrate is mixed with microbial fermentation products and aerobic fermentation is induced to obtain the pretreated substrate.

[0036] The composite seedling substrate is made of coconut coir, peat and vermiculite in a mass ratio of 5:2:1; the steam sterilization temperature is 90℃, the pressure is 0.05MPa and the time is 40min; the microbial fermentation product is corn cob powder containing Bacillus subtilis and Trichoderma, and its addition amount is 10% of the volume of the composite seedling substrate; the aerobic fermentation induction time is 5 days, during which the pile is turned over to maintain the temperature at 45℃.

[0037] S2. Fill the pretreated substrate into the seedling container and inject a complexed trace element solution into it for pre-moistening to obtain the seedling bed.

[0038] The complexed trace element solution contains EDTA-iron, EDTA-zinc and boric acid, with mass concentrations of 0.1%, 0.05% and 0.02%, respectively. Pre-wetting controls the substrate moisture content of the seedling bed at 55%, and adjusts the EC value of the substrate to 0.4 mS / cm, with a porosity of 60%.

[0039] S3. Collect strawberry runner tips, peel off the meristem under aseptic conditions, and place them in an induction medium containing melatonin and ascorbic acid for dark culture to obtain virus-free pretreated cuttings.

[0040] The process involved separating the shoot apical meristem from the shoot apical growing point, which was 0.2 mm in size. The induction medium was based on MS medium, with the addition of 0.5 mg / L 6-BA, 0.01 mg / L NAA, 0.1 mg / L melatonin, and 10 mg / L ascorbic acid. The dark culture was carried out at 22°C and 70% humidity for 7 days.

[0041] S4. Insert the virus-free pretreated cuttings into the seedbed and fill the cutting opening with a water-retaining fungal symbiotic agent to obtain symbiotic cuttings.

[0042] The water-retaining fungal symbiotic agent is a mixture of mycorrhizal fungal agent, superabsorbent resin and wood ash in a mass ratio of 1:5:2. The filling method is to apply the water-retaining fungal symbiotic agent in dry powder form around the cutting after the cutting is covered with soil, with a dosage of 0.5g per cutting.

[0043] S5. Photoperiod regulation and rhizosphere temperature gradient stimulation are applied to symbiotic cuttings to induce directional root development and obtain robust root seedlings.

[0044] The photoperiod regulation involved treating the cuttings with a red light to far-red light ratio of 1:1 and an irradiance of 100 μmol·m⁻¹ within one day of propagation. -2 ·s -1 The daily light exposure is 14 hours; the rhizosphere temperature gradient stimulation is achieved by maintaining a diurnal temperature range of 8°C through water bath circulation, with a daytime temperature of 22°C and a nighttime temperature of 10°C. During this process, a root-promoting agent is applied, which is prepared by mixing potassium humate, sodium nitroprusside, and calcium nitrate in a mass ratio of 10:1:5, diluted 800 times, and applied as a root drench every 5 days.

[0045] S6. After the roots of the strong-rooted seedlings have filled the seedling container, they are subjected to gradient drought stress and nitrogen reduction and phosphorus increase treatment to induce flower bud differentiation and obtain seedlings that can be planted.

[0046] The gradient drought stress treatment involved gradually reducing the substrate moisture content from 60% to 30% at a daily decrease of 5%, with each moisture content gradient maintained for 2 days. The nitrogen reduction and phosphorus increase treatment involved stopping nitrogen fertilizer application and foliar spraying with a 0.2% potassium dihydrogen phosphate solution every 3 days for 3 consecutive applications. Simultaneously, a low-temperature induction treatment was implemented: the ambient temperature was reduced from 18℃ to 8℃ at a daily rate of 2℃ and maintained at 8℃ for 7 days, while the daily light duration was controlled at 8 hours and the light intensity at 80 μmol·m⁻². -2 ·s -1 The criteria for obtaining seedlings suitable for transplanting are: seedling age 45 days, root activity ≥200 μg·g. -1 ·h -1 The rhizome is ≥0.8cm thick, has 4 unfolded leaves, and the flower bud differentiation rate reaches 80%.

[0047] Example 2: This example provides a method for efficient strawberry seedling cultivation, which includes the following steps: S1. After steam sterilization, the composite seedling substrate is mixed with microbial fermentation products and aerobic fermentation is induced to obtain the pretreated substrate.

[0048] The composite seedling substrate is composed of coconut coir, peat, and vermiculite mixed in a mass ratio of 6:2.5:1.5; the steam sterilization temperature is 100℃, the pressure is 0.075MPa, and the time is 50min; the microbial fermentation product is corn cob powder containing Bacillus subtilis and Trichoderma, and its addition amount is 12.5% ​​of the volume of the composite seedling substrate; the aerobic fermentation induction time is 6 days, during which the pile is turned over to maintain the temperature at 50℃.

[0049] S2. Fill the pretreated substrate into the seedling container and inject a complexed trace element solution into it for pre-moistening to obtain the seedling bed.

[0050] The complexed trace element solution contains EDTA-iron, EDTA-zinc and boric acid, with mass concentrations of 0.15%, 0.075% and 0.035%, respectively. Pre-wetting controls the substrate moisture content of the seedling bed to 60%, and adjusts the EC value of the substrate to 0.5 mS / cm, with a porosity of over 60%.

[0051] S3. Collect strawberry runner tips, peel off the meristem under aseptic conditions, and place them in an induction medium containing melatonin and ascorbic acid for dark culture to obtain virus-free pretreated cuttings.

[0052] The process involved separating the shoot apical meristem from the shoot apical growing point, which was 0.35 mm in size. The induction medium was based on MS medium, supplemented with 0.75 mg / L 6-BA, 0.03 mg / L NAA, 0.3 mg / L melatonin, and 15 mg / L ascorbic acid. The dark culture was conducted at 24°C and 75% humidity for 8.5 days.

[0053] S4. Insert the virus-free pretreated cuttings into the seedbed and fill the cutting opening with a water-retaining fungal symbiotic agent to obtain symbiotic cuttings.

[0054] The water-retaining fungal symbiotic agent is a mixture of mycorrhizal fungal agent, superabsorbent resin and wood ash in a mass ratio of 1.5:6.5:2.5. The filling method is to apply the water-retaining fungal symbiotic agent in dry powder form around the cutting after the cutting is covered with soil, with a dosage of 0.75g per cutting.

[0055] S5. Photoperiod regulation and rhizosphere temperature gradient stimulation are applied to symbiotic cuttings to induce directional root development and obtain robust root seedlings.

[0056] The photoperiod regulation involved treating the cuttings with a red light to far-red light ratio of 1.5:1 and a light intensity of 125 μmol·m⁻¹ for 5 days after planting. -2 ·s -1 The daily light exposure is 15 hours; the rhizosphere temperature gradient stimulation is achieved by maintaining a diurnal temperature range of 10℃ through water bath circulation, with a daytime temperature of 23.5℃ and a nighttime temperature of 12℃. During this process, a root-promoting agent is applied, prepared from potassium humate, sodium nitroprusside, and calcium nitrate in a mass ratio of 12.5:1.5:6.5, diluted 900 times, and applied as a root drench every 6 days.

[0057] S6. After the roots of the strong-rooted seedlings have filled the seedling container, they are subjected to gradient drought stress and nitrogen reduction and phosphorus increase treatment to induce flower bud differentiation and obtain seedlings that can be planted.

[0058] The gradient drought stress treatment involved gradually reducing the substrate moisture content from 62.5% to 32.5% at a daily decrease of 6.5%, maintaining each moisture content gradient for 2.5 days. The nitrogen reduction and phosphorus increase treatment involved stopping nitrogen fertilizer application and foliar spraying with a 0.25% potassium dihydrogen phosphate solution every 3 days for 3.5 consecutive applications. Simultaneously, a low-temperature induction treatment was implemented: the ambient temperature was reduced from 18℃ to 8℃ at a daily rate of 2℃ and maintained at 8℃ for 8.5 days, while controlling the daily light duration to 9 hours and the light intensity to 100 μmol·m⁻². -2 ·s -1 The criteria for obtaining seedlings suitable for transplanting are: seedling age 52 days, root activity ≥200 μg·g. -1 ·h -1 The rhizome is ≥0.8cm thick, has 4.5 unfolded leaves, and the flower bud differentiation rate reaches over 80%.

[0059] Example 3: This example provides a method for efficient strawberry seedling cultivation, comprising the following steps: S1. After steam sterilization, the composite seedling substrate is mixed with microbial fermentation products and aerobic fermentation is induced to obtain the pretreated substrate.

[0060] The composite seedling substrate is composed of coconut coir, peat, and vermiculite mixed in a mass ratio of 7:3:2; the steam sterilization temperature is 110℃, the pressure is 0.1MPa, and the time is 60min; the microbial fermentation product is corn cob powder containing Bacillus subtilis and Trichoderma, and its addition amount is 15% of the volume of the composite seedling substrate; the aerobic fermentation induction time is 7 days, during which the pile is turned over to maintain the temperature at 55℃.

[0061] S2. Fill the pretreated substrate into the seedling container and inject a complexed trace element solution into it for pre-moistening to obtain the seedling bed.

[0062] The complexed trace element solution contains EDTA-iron, EDTA-zinc and boric acid, with mass concentrations of 0.2%, 0.1% and 0.05%, respectively. Pre-wetting controls the substrate moisture content of the seedling bed to 65%, and adjusts the EC value of the substrate to 0.6 mS / cm, with a porosity of over 60%.

[0063] S3. Collect strawberry runner tips, peel off the meristem under aseptic conditions, and place them in an induction medium containing melatonin and ascorbic acid for dark culture to obtain virus-free pretreated cuttings.

[0064] The process involved separating the shoot apical meristem from the shoot apical growing point, which was 0.5 mm in size. The induction medium was based on MS medium, with the addition of 1.0 mg / L 6-BA, 0.05 mg / L NAA, 0.5 mg / L melatonin, and 20 mg / L ascorbic acid. The dark culture was carried out at 26°C and 80% humidity for 10 days.

[0065] S4. Insert the virus-free pretreated cuttings into the seedbed and fill the cutting opening with a water-retaining fungal symbiotic agent to obtain symbiotic cuttings.

[0066] The water-retaining fungal symbiotic agent is a mixture of mycorrhizal fungal agent, superabsorbent resin and wood ash in a mass ratio of 2:8:3. The filling method is to apply the water-retaining fungal symbiotic agent in dry powder form around the cutting after the cutting is covered with soil, with a dosage of 1.0g per cutting.

[0067] S5. Photoperiod regulation and rhizosphere temperature gradient stimulation are applied to symbiotic cuttings to induce directional root development and obtain robust root seedlings.

[0068] The photoperiod regulation involved treating the cuttings with a red light to far-red light ratio of 2:1 and a light intensity of 150 μmol·m⁻¹ for the first 10 days after propagation. -2 ·s -1 The daily light exposure time is 16 hours; the rhizosphere temperature gradient stimulation is achieved by maintaining the diurnal temperature difference of the substrate at 12℃ through water bath circulation, with a daytime temperature of 25℃ and a nighttime temperature of 14℃; during this process, a root-promoting agent is applied, which is prepared by potassium humate, sodium nitroprusside, and calcium nitrate in a mass ratio of 15:2:8, diluted 1000 times, and applied to the roots every 7 days.

[0069] S6. After the roots of the strong-rooted seedlings have filled the seedling container, they are subjected to gradient drought stress and nitrogen reduction and phosphorus increase treatment to induce flower bud differentiation and obtain seedlings that can be planted.

[0070] The gradient drought stress involved gradually reducing the substrate moisture content from 65% to 35% at a daily decrease of 8%, with each moisture content gradient maintained for 3 days. The nitrogen reduction and phosphorus increase treatment involved stopping nitrogen fertilizer application and foliar spraying with a 0.3% potassium dihydrogen phosphate solution every 3 days for 4 consecutive applications. Simultaneously, a low-temperature induction treatment was implemented: the ambient temperature was reduced from 18℃ to 8℃ at a daily rate of 2℃ and maintained at 8℃ for 10 days, while the daily light duration was controlled at 10 hours and the light intensity at 120 μmol·m⁻². -2 ·s -1 The criteria for obtaining seedlings suitable for transplanting are: seedling age 60 days, root activity ≥200 μg·g -1 ·h -1 The rhizome has a diameter of ≥0.8cm, 5 unfolded leaves, and a flower bud differentiation rate of over 80%.

[0071] Comparative Example 1: This comparative example refers to the content of Example 1, except that the composite seedling substrate described in step S1 is composed of coconut coir, peat moss and vermiculite mixed in a mass ratio of 7:1:2, and the rest of the contents are the same as in Example 1.

[0072] Comparative Example 2: This comparative example refers to the content of Example 1, except that the amount of microbial fermentation product added in step S1 is 3% of the volume of the composite seedling substrate, and the rest is the same as Example 1.

[0073] Comparative Example 3: This comparative example refers to the content of Example 1, except that the size of the apical meristem stripped in step S3 is 0.8 mm, and the rest of the content is the same as Example 1.

[0074] Comparative Example 4: This comparative example refers to the content of Example 1, except that the water-retaining fungal symbiotic agent is not filled in step S4, and the rest of the content is the same as Example 1.

[0075] Comparative Example 5: This comparative example refers to the content of Example 1, except that the ratio of red light to far-red light used in the photoperiod modulation in step S5 is 1:4, and the rest is the same as Example 1.

[0076] Comparative Example 6: This comparative example refers to the content of Example 1, except that the gradient drought stress treatment is not performed in step S6, and the rest is the same as Example 1.

[0077] Performance testing Sample preparation: Strawberry seedlings were prepared according to the methods described in Examples 1-3 as experimental groups; at the same time, strawberry seedlings were prepared according to the methods described in Comparative Examples 1-6 as control groups for comparison; the seed source, seedling environment and management conditions of all experimental groups and control groups were kept consistent except for the differences in the methods themselves. 300 strawberry seedlings were prepared for each method, and the results were repeated three times. The average value was used for subsequent testing.

[0078] Seedling efficiency and uniformity testing: When the plants obtained by each method reached their respective recorded standards for transplanting, 50 seedlings were randomly selected from each group. The seedling age, plant height, rootstock thickness, and number of unfolded leaves of each seedling were measured and recorded. The shoot tip growth point was observed through a dissecting microscope, and the number of plants with flower bud differentiation was counted to calculate the flower bud differentiation rate. At the same time, the coefficient of variation of each plant in the same treatment group on key indicators such as plant height and root collar thickness was calculated to assess the uniformity of seedlings. The seedlings in each group were transplanted into a standard production greenhouse at the same time, and the number of days required from transplanting to 50% of the plants having initial flowering was recorded to assess the effect of early flowering. Root activity was determined using the triphenyltetrazolium chloride method, root collar thickness was measured using a digital vernier caliper, and flower bud differentiation was defined as the swelling of the growth point and the formation of sepal primordia.

[0079] Table 1: Results of Seedling Efficiency and Uniformity Testing

[0080] Substrate activity and microbial community detection: After aerobic fermentation induction in step S1, samples were taken from the pretreated substrates prepared in each example and comparative example; the porosity, water holding capacity, conductivity, and pH of the substrates were measured. The total bacterial and fungal counts in the substrates were determined using the dilution plating method with beef extract peptone medium and Bengal red medium, respectively. Selective media were used for specific counting of Bacillus subtilis and Trichoderma to assess the colonization of beneficial bacteria. Simultaneously, high-throughput sequencing technology was used to analyze the microbial community structure of the substrates and assess the relative abundance of pathogenic microorganisms. Substrate porosity was measured using the ring cutter method, conductivity was measured using a conductivity meter, and microbial counting was performed according to the People's Republic of China National Standard "Determination of Microbial Agents in Fertilizers".

[0081] Table 2: Results of matrix activity and microbial community detection

[0082] Detection of cutting survival and mycorrhizal symbiosis: On the 21st day after cutting in step S4, the number of surviving cuttings in each treatment group was counted, and the survival rate was calculated. At the same time, 10 cuttings were randomly dug from each treatment group, and the soil around the roots was carefully washed off. Fresh fine root segments were cut and stained with trypan blue. The mycelium, arbuscular structures, vesicles, etc. of arbuscular mycorrhizal fungi were observed under a microscope, and the mycorrhizal infection rate was calculated according to the grid cross method. The time and number of new roots after cutting were recorded, and the rooting speed was evaluated. The mycorrhizal infection rate is equal to the percentage of the root segment length with mycorrhizal structure observed to the total observed root segment length.

[0083] Table 3: Results of Cuttings Survival and Mycorrhizal Symbiosis Detection

[0084] Root development status detection: After the photoperiod regulation and rhizosphere temperature gradient stimulation treatment described in step S5, 10 robust root seedlings were randomly selected from each treatment group. A root scanner was used to analyze the total root length, root surface area, average root diameter, root volume, and number of root tips. The roots were washed, dried, and weighed fresh. They were then dried in an oven to constant weight, weighed dry, and the root-to-shoot ratio was calculated. Root dehydrogenase activity was determined using the nitroblue tetrazolium reduction method as a direct characterization of root vigor. Root morphology analysis was performed using the WinRHIZO root analysis system, and root dehydrogenase activity was determined according to the methods described in "Experimental Guide to Plant Physiology".

[0085] Table 4: Results of Root Development Status Detection

[0086] Flower bud differentiation induction effect detection: The contents of abscisic acid and gibberellin in leaves were determined by enzyme-linked immunosorbent assay (ELISA); total ribonucleic acid was extracted from leaves, reverse transcribed into complementary deoxyribonucleic acid, and the relative expression levels of flowering genes, such as the strawberry flowering site T gene and flowering trajectory T gene, were detected by real-time quantitative polymerase chain reaction (qPCR); the correlation between these molecular biological indicators and the flower bud differentiation rate obtained from anatomical observation was analyzed; the content of plant endogenous hormones was determined using a commercially available ELISA kit, and gene expression analysis followed the general experimental procedure of real-time quantitative polymerase chain reaction, with the elongation factor gene as an internal reference gene.

[0087] Table 5: Results of flower bud differentiation induction effect detection

[0088] Example Conclusion: As can be seen from Examples 1-3 and Comparative Example 1, and Table 1, the optimized ratio of the composite seedling substrate improves the physical structure and chemical properties of the substrate, providing a more stable rhizosphere environment for seedling growth, thereby enhancing the uniformity of seedlings and their early flowering ability.

[0089] Based on Examples 1-3 and Comparative Example 2, and in conjunction with Table 2, it can be seen that adding an appropriate amount of microbial fermentation product can promote the colonization of beneficial bacteria and the bioactivation of the substrate, thereby laying the foundation for the healthy growth of cuttings by inhibiting pathogenic microorganisms and improving the micro-ecological environment.

[0090] As can be seen from Examples 1-3 and Comparative Example 3, and Table 3, controlling the size of the shoot tip meristem within a suitable range can improve the detoxification effect and the activity of the cuttings, thereby promoting the survival rate after cutting and the establishment of mycorrhizal symbiosis, and providing a guarantee for rapid rooting.

[0091] As can be seen from Examples 1-3 and Comparative Example 4, and Table 3, the use of water-retaining fungal symbiotic agents can improve the survival rate and mycorrhizal infection rate of cuttings through the synergistic effects of physical water retention, chemical antibacterial action, and biological symbiosis, thus providing conditions for root development.

[0092] Based on Examples 1-3 and Comparative Example 5, and in conjunction with Table 4, it can be seen that optimizing the light quality ratio in photoperiod regulation can effectively promote the directional development and vitality enhancement of the root system through the synergistic effect of light signal transmission and rhizosphere temperature gradient stimulation, thereby obtaining stronger seedlings with robust roots.

[0093] As can be seen from Examples 1-3 and Comparative Example 6, and Table 5, gradient drought stress treatment, through its synergistic effect with nitrogen reduction and phosphorus increase and low temperature induction, effectively regulates the balance of endogenous hormones and the expression of flowering genes, thereby improving the flower bud differentiation rate and synchronicity, and ensuring that seedlings have the potential for early flowering.

[0094] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for efficient strawberry seedling cultivation, characterized in that, Includes the following steps: S1. After steam sterilization, the composite seedling substrate is mixed with microbial fermentation products and aerobic fermentation is induced to obtain the pretreated substrate. S2. Fill the pretreated substrate into the seedling container and inject a complexed trace element solution into it for pre-wetting to obtain the seedling bed. S3. Collect strawberry runner tips, peel off the meristems of the stolons under sterile conditions, and place them in an induction medium containing melatonin and ascorbic acid for dark culture to obtain virus-free pretreated cuttings; S4. Insert the virus-free pretreated cuttings into the seedbed and fill the cutting opening with a water-retaining fungal symbiotic agent to obtain symbiotic cuttings. S5. Photoperiod regulation and rhizosphere temperature gradient stimulation are applied to the symbiotic cuttings to induce directional root development and obtain robust root seedlings. S6. After the roots of the strong-rooted seedlings have filled the seedling container, they are subjected to gradient drought stress and nitrogen reduction and phosphorus increase treatment to induce flower bud differentiation and obtain seedlings that can be planted.

2. The method for efficient strawberry seedling cultivation according to claim 1, characterized in that, In step S1, the composite seedling substrate is composed of coconut coir, peat, and vermiculite mixed in a mass ratio of (5-7):(2-3):(1-2); the steam sterilization temperature is 90-110℃, the pressure is 0.05-0.1MPa, and the time is 40-60min; the microbial fermentation product is corn cob powder containing Bacillus subtilis and Trichoderma, and its addition amount is 10%-15% of the volume of the composite seedling substrate; the aerobic fermentation induction time is 5-7 days, during which the pile is turned over to maintain the temperature at 45-55℃.

3. The method for efficient strawberry seedling cultivation according to claim 1, characterized in that, In step S2, the complexed trace element solution contains EDTA-iron, EDTA-zinc, and boric acid, with mass concentrations of 0.1%–0.2%, 0.05%–0.1%, and 0.02%–0.05%, respectively. The pre-wetting process controls the substrate moisture content of the seedling bed to 55%–65%, adjusts the EC value of the substrate to 0.4–0.6 mS / cm, and achieves a porosity of over 60%.

4. The method for efficient strawberry seedling cultivation according to claim 1, characterized in that, In step S3, the stripping of shoot apical meristem involves stripping shoot apical growth points of 0.2–0.5 mm in size; the induction medium is based on MS medium, supplemented with 0.5–1.0 mg / L 6-BA, 0.01–0.05 mg / L NAA, 0.1–0.5 mg / L melatonin, and 10–20 mg / L ascorbic acid; the dark culture temperature is 22–26 °C, the humidity is 70%–80%, and the culture time is 7–10 days.

5. The method for efficient strawberry seedling cultivation according to claim 1, characterized in that, In step S4, the water-retaining fungal symbiotic agent is a mixture of mycorrhizal fungal agent, superabsorbent resin and wood ash in a mass ratio of (1-2):(5-8):(2-3); the filling is to apply the water-retaining fungal symbiotic agent in dry powder form around the cutting after the cutting is covered with soil, with a dosage of 0.5-1.0g per cutting.

6. The method for efficient strawberry seedling cultivation according to claim 1, characterized in that, In step S5, the photoperiod regulation is as follows: within 1 to 10 days after cutting, use a light treatment with a red light to far-red light ratio of 1:1 to 2:1, and a light intensity of 100 to 150 μmol·m⁻¹. -2 ·s -1 The daily light exposure time is 14 to 16 hours; the rhizosphere temperature gradient stimulation is achieved by maintaining the diurnal temperature difference of the substrate at 8 to 12°C through water bath circulation, with the daytime temperature at 22 to 25°C and the nighttime temperature at 10 to 14°C.

7. The method for efficient strawberry seedling cultivation according to claim 1, characterized in that, In step S5, during the process of inducing the directional development of the root system, a root-promoting agent is applied. The root-promoting agent is prepared by potassium humate, sodium nitroprusside and calcium nitrate in a mass ratio of (10-15):(1-2):(5-8), diluted 800-1000 times and applied to the roots once every 5-7 days.

8. The method for efficient strawberry seedling cultivation according to claim 1, characterized in that, In step S6, the gradient drought stress is as follows: the substrate moisture content is gradually reduced from 60% to 65% to 30% to 35%, with a daily reduction of 5% to 8%, and each moisture content gradient is maintained for 2 to 3 days; the nitrogen reduction and phosphorus increase treatment is as follows: nitrogen fertilizer application is stopped, and a 0.2% to 0.3% potassium dihydrogen phosphate solution is sprayed on the leaves once every 3 days, for a total of 3 to 4 times.

9. The method for efficient strawberry seedling cultivation according to claim 1, characterized in that, In step S6, during the induction of flower bud differentiation, a low-temperature induction treatment is also performed: the ambient temperature is lowered from 18°C ​​to 8°C at a rate of 2°C per day, and maintained at 8°C for 7–10 days, while the daily light duration is controlled to be 8–10 hours and the light intensity to be 80–120 μmol·m⁻². -2 ·s -1 .

10. The method for efficient strawberry seedling cultivation according to claim 1, characterized in that, In step S6, the criteria for obtaining seedlings suitable for transplanting are: seedling age 45–60 days, root activity ≥200 μg·g - ¹·h - ¹, with a rhizome thickness ≥ 0.8 cm, 4–5 unfolded leaves, and a flower bud differentiation rate of over 80%.

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