Method for improving survival rate of forsythia tender branch cutting seedling

Abstract

This invention belongs to the field of plant seedling technology, specifically relating to a method for improving the survival rate of Forsythia suspensa cuttings. Specifically, fruiting mother trees are selected, and semi-lignified branches of the current year are collected as cuttings, retaining plump buds. The cuttings are soaked in a rooting agent compound solution and then dried for later use. The treated cuttings are then inserted into a gradient substrate and thoroughly watered after planting. The stomatal conductance of the cutting leaves and the electrical conductivity at the base of the cuttings are monitored in real time. The substrate temperature, spraying frequency, shading rate, and ventilation are adaptively adjusted in a closed-loop manner according to the physiological thresholds of different rooting stages of Forsythia suspensa cuttings. Stress-resistant fertilizer is applied according to the physiological state of the cuttings, and disease control and daily management are carried out. This method improves the survival rate of Forsythia suspensa cuttings, reduces the rate of cutting rot, exhibits strong environmental adaptability, and high seedling stability.

Description

Technical Field

[0001] This invention belongs to the field of plant seedling technology, specifically relating to a method for improving the survival rate of Forsythia suspensa cuttings. Background Technology

[0002] Forsythia, a deciduous shrub belonging to the genus Forsythia in the family Oleaceae, is a commonly used and widely distributed traditional Chinese medicine. Its fruit can be used medicinally, possessing effects such as clearing heat and detoxifying, reducing swelling and dissipating nodules. Forsythia also has high landscaping value, with early flowering and strong ornamental appeal, leading to increasing market demand year by year. Currently, forsythia propagation mainly relies on softwood cuttings. This method has advantages such as rapid propagation, stable genetic traits in seedlings, a high propagation coefficient, and low cost, making it the mainstream method for large-scale forsythia seedling cultivation.

[0003] However, existing Forsythia softwood cutting techniques generally have many shortcomings, and all improvements are merely static parameter adjustments in a single dimension, failing to create a synergistic effect and fundamentally solve the industry's pain points. Specifically, these shortcomings include: using only a single rooting agent (such as IBA or ABT) or a binary compound treatment, lacking the synergistic effects of stress resistance, repair, and antibacterial properties; and a crude soaking process without controlling soaking temperature and stirring frequency, resulting in uneven penetration of the treatment solution, easy rotting of cuttings, and slow rooting speed. Secondly, most use a single substrate or a simple mixed substrate. Even if a substrate design is used, it is only a simple layering of "gravel + coarse river sand + fine river sand," without clear functional zoning and precise proportions, failing to meet the needs of drainage, aeration, fertilizer retention, and root induction, easily leading to waterlogging and rotting or dehydration and drying out. Furthermore, existing technologies all use fixed parameters for environmental control, such as fixed spraying frequency, fixed substrate temperature, and fixed shading rate, which cannot adapt to actual seedling variables such as individual differences in cuttings, weather changes, and substrate condition fluctuations, resulting in large fluctuations in survival rate and a high rate of cutting rot.

[0004] In view of the shortcomings of the existing technology, developing a technical solution that can improve the survival rate and stability of Forsythia seedlings, reduce the rate of rotten ears, and has strong adaptability has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] To address the aforementioned shortcomings in the existing technology, this invention provides a method for improving the survival rate of Forsythia suspensa cuttings to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A method for improving the survival rate of Forsythia suspensa cuttings, characterized by the following steps: S1: Select fruiting mother trees of Forsythia suspensa, collect semi-lignified branches of the current year as cuttings, and retain plump buds; S2: Soak the cuttings in a rooting agent compound treatment solution and then air dry them for later use; S3: Insert the prepared cuttings into the gradient substrate and water thoroughly after planting; S4: Real-time monitoring of leaf stomatal conductance and base electrical conductivity of cuttings, adaptive closed-loop adjustment of substrate temperature, spraying frequency, shading rate and ventilation according to the physiological thresholds of different stages of rooting of Forsythia suspensa tender branches. S5: Apply stress-resistant fertilizer according to the physiological state of the cuttings, and carry out disease prevention and control and daily management.

[0007] Furthermore, in the selection of cuttings, the Forsythia fruiting mother trees are selected from 3-year-old, vigorous plants free from pests and diseases, and with stable fruit production. Cuttings are collected from the middle section of the current year's semi-lignified fruiting branches on the outer periphery of the canopy, facing the sun. The cuttings are 8–10 cm long and 0.3–0.5 cm in diameter, retaining two plump buds and one dormant bud at the base. This limitation overcomes the shortcomings of arbitrary cutting selection in existing technologies. The limitation on cutting diameter and dormant buds can further improve the rooting rate and seedling uniformity. The selection of the middle section of the fruiting branch facing the sun ensures sufficient nutrients and high activity in the cuttings, guaranteeing the quality of the cuttings from the source and solving the problems of weak rooting potential and low survival rate of cuttings in existing technologies.

[0008] Furthermore, in step S2, the cuttings are also pruned and the leaves are treated; the rooting agent compound treatment solution is a compound solution of indolebutyric acid, salicylic acid and proline, and is soaked for 2.5 hours.

[0009] The lower cut of the cutting should be made at a 45° angle below a node to increase the contact area with the substrate and promote rooting. The upper cut should be made horizontally, 0.5–0.8 cm away from the apical bud to reduce water evaporation. Remove all lower leaves, leaving 1–2 small leaves at the top, and cut them off by half. This ensures normal photosynthesis while effectively reducing transpiration and preventing the cutting from drying out. The base of the cutting should be cut smoothly and without damage to reduce the risk of pathogen infection.

[0010] Immerse the base 3–4 cm of the cuttings in the triple-component treatment solution described above for 2.5 hours at 22±1℃ in the dark, stirring every 30 minutes to ensure even penetration. After soaking, allow the base of the cuttings to air dry for 10–15 minutes before planting to further reduce the risk of pathogen infection and improve rooting efficiency. Furthermore, the gradient matrix of S3 is a gradient matrix with different functions, specifically including a drainage and aeration layer, a rooting induction layer, and a water retention and drought prevention layer. The bottom layer of the gradient matrix also includes a slow-release regulation layer, specifically composed of porous biochar, chitosan-based responsive gel, and nano-antibacterial particles. The matrix is ​​sterilized before use. The first layer is a water-retaining and moisture-proof layer, composed of fine sand and coconut coir; the second layer is a root-inducing layer, composed of humus and vermiculite; the third layer is a drainage and aeration layer, composed of coarse river sand and perlite; and the bottom layer is a slow-release regulating layer, using porous biochar as a carrier to load slow-release materials and antibacterial agents.

[0011] Before using any substrate, spray with a 0.5% carbendazim solution at a rate of 10–15 L per cubic meter of substrate. After stirring thoroughly, cover with plastic film and seal for sterilization for 3–5 days. After sterilization, uncover the film and ventilate for 1–2 days. When the substrate is dry enough to clump together when squeezed but crumble easily when released, it is ready for use. At the same time, control the pH of the gradient substrate at 6.5–7.0, the bulk density at 0.8–1.0 g / cm³, and the porosity at 55%–60% to precisely match the substrate environment requirements for the rooting of Forsythia cuttings, further improving the rooting rate and reducing the occurrence of diseases.

[0012] Furthermore, in the cutting operation of S3, the cutting depth is 1 / 2–2 / 3 of the length of the cutting and the base of the cutting is located in the middle rooting induction layer.

[0013] Before planting, make holes in the seedbed at a spacing of 8–10 cm between plants and 10–12 cm between rows. The hole diameter should be slightly larger than the diameter of the cutting to avoid direct insertion and damage to the base of the cutting. Insert the treated cuttings into the gradient substrate at a depth of 1 / 2–2 / 3 of the cutting length, ensuring that the base of the cutting is located in the middle rooting induction layer. This will ensure that the base of the cutting can fully absorb the nutrients and water from the middle substrate, improving the rooting effect. After planting, compact the substrate and immediately water thoroughly. Add 0.05% amino oligosaccharide to the rooting water to further enhance the cuttings' resistance to stress and reduce pathogen infection.

[0014] Furthermore, the adaptive closed-loop adjustment of S4 is specifically adjusted according to the different stages of rooting of Forsythia suspensa tender branches, using the physiological thresholds of leaf stomatal conductance and cutting base electrical conductivity corresponding to that stage.

[0015] The specific steps in this process are as follows: 1. Determining the physiological marker thresholds for three key stages of rooting in Forsythia suspensa tender shoots. The physiological markers selected were stomatal conductance of leaves and electrical conductivity at the base of the cuttings, which directly reflect the water status, physiological activity, and rooting progress of the cuttings. Specific thresholds are as follows: ① Callus formation period (0–7 days after cutting): stomatal conductance of leaves 150–200 mmol / m·s, electrical conductivity at the base of the cutting 0.8–1.0 mS / cm. During this stage, the cuttings mainly undergo wound healing, requiring controlled humidity and prevention of pathogen infection; ② Root primordium development period (8–20 days after cutting): stomatal conductance of leaves 200–250 mmol / m·s, electrical conductivity at the base of the cutting 1.0–1.2 mS / cm. During this stage, the cuttings begin to differentiate root primordia, requiring sufficient water, nutrients, and suitable temperature; ③ Root growth period (after 21 days after cutting): stomatal conductance of leaves 250–300 mmol / m·s, electrical conductivity at the base of the cutting 1.2–1.5 mS / cm. At this stage, the root system grows rapidly (mS / cm), requiring increased light and nutrient supply to enhance the seedlings' resistance to adverse conditions.

[0016] 2. Real-time monitoring system setup Miniature sensors are installed in the seedling shed, with each sensor corresponding to the leaf and base of the cutting. The sensors collect data on the stomatal conductance of the leaf and the electrical conductivity of the base of the cutting in real time. The data is transmitted to the control terminal to achieve real-time monitoring of physiological parameters without the need for manual intervention.

[0017] 3. Adaptive Closed-Loop Control Logic: The control terminal has a built-in collaborative control algorithm specific to Forsythia suspensa. Based on real-time monitored physiological parameters, it automatically adjusts the substrate temperature, spray frequency, shading rate, and ventilation volume, forming a closed-loop system of "monitoring-analysis-adjustment-feedback". The specific control logic is as follows: ① Spraying frequency adjustment: When the leaf stomatal conductance is greater than the upper limit of the corresponding stage threshold, it indicates that the transpiration of the cuttings is too strong and the water loss is too fast. Shorten the spraying interval to 5 minutes. When the leaf stomatal conductance is less than the lower limit of the corresponding stage threshold, it indicates that the air humidity is too high and bacteria are prone to grow. Extend the spraying interval to 12 minutes. Use automatic spraying equipment and control the spraying pressure at 0.15–0.2 MPa. Spraying interval is 5–12 minutes during the day with each spray lasting 3 seconds. Spraying interval is 20–40 minutes at night with each spray lasting 3 seconds to ensure that the air humidity is maintained at 82–85%. ② Substrate temperature adjustment: When the electrical conductivity at the base of the cutting is less than the lower limit of the threshold for the corresponding stage, it indicates insufficient nutrient absorption in the substrate and slow rooting speed. The substrate temperature should be increased to 24℃. When the electrical conductivity at the base of the cutting is greater than the upper limit of the threshold for the corresponding stage, it indicates that the substrate moisture is too high and the cutting is prone to rotting. The substrate temperature should be reduced to 22℃. The substrate constant temperature benchmark is 23±1℃, and geothermal heating is used to achieve precise temperature control. ③ Shading rate adjustment: Adjust according to the rooting stage. In the early stage of cutting (callus formation period), the shading rate is 80% to avoid strong direct sunlight scorching the cuttings and causing rapid water evaporation. In the root primordia development period, the shading rate is 70% to appropriately increase light and promote photosynthesis. During the root growth period, gradually reduce to full light to help the seedlings grow healthily. ④ Ventilation adjustment: Ventilate 1–2 times a day, 15–20 minutes each time. Control the temperature at 20–25℃ during ventilation to avoid substrate temperature fluctuations exceeding 2℃. Maintain air circulation to further reduce the risk of disease occurrence. In conjunction with substrate constant temperature and rhythmic spraying, a stable environmental system is formed.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. A dynamic closed-loop synergistic regulation system for physiological markers of Forsythia suspensa tender branches is proposed, which upgrades the seedling cultivation mode from "static preset" to "dynamic adaptive". It is not affected by weather, season, or differences in cutting batches. Through real-time monitoring and adaptive adjustment, it can adapt to different environmental conditions and cutting status, ensuring the stability of seedling cultivation results and making it suitable for large-scale industrial seedling cultivation.

[0019] 2. Employing a functionally differentiated gradient substrate, this method utilizes a gradient design with varying upper and lower structures, air permeability, and water retention, along with a slow-release regulating layer, to simultaneously meet the environmental needs of different parts of the cuttings at different growth stages. Through dynamic and coordinated regulation throughout the entire process, and with each technical step not simply being superimposed but mutually supporting and synergistically enhancing each other, a technical effect of "1+1>2" is achieved. This improves the survival rate of cuttings, reduces the rate of cutting rot, and increases rooting efficiency, solving the problems of existing technologies.

[0020] 3. It is easy to operate, low in cost, uses readily available materials, requires no complex equipment, has low sensor cost, and has a high degree of standardization in each step, making it easy to master. It is suitable for large-scale seedling cultivation, can significantly reduce seedling costs, and has broad prospects for promotion and application. Attached Figure Description

[0021] Figure 1 Flowchart of a method for improving the survival rate of Forsythia suspensa cuttings Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] Example 1 A method for improving the survival rate of Forsythia suspensa cuttings includes the following steps: 1. Selection of cuttings Select healthy, disease-free, 3-year-old Forsythia fruiting mother trees, collect the current year's sun-facing semi-lignified fruiting branches from the outer periphery of the canopy, and cut the middle section of the branches as cuttings. The cuttings should be 9cm long, 0.4cm in diameter, retain 2 plump buds, and have 1 dormant bud at the base of the cutting.

[0024] 2. Cutting treatment Make a 45° angled cut below a node on the lower part of the cutting, and a straight cut on the upper part, 0.6 cm from the apical bud. Remove all lower leaves, leaving one small leaf at the top, which is then cut off by half. The base of the cutting should be smooth and undamaged. Prepare a triple compound treatment solution containing 250 mg / L indolebutyric acid, 15 mg / L salicylic acid, and 60 mg / L proline. Immerse the base of the cutting (3.5 cm) in the treatment solution and soak at 22°C in the dark for 2.5 hours, stirring every 30 minutes during the soaking process. After soaking, allow the base of the cutting to air dry for 12 minutes before use.

[0025] 3. Gradient matrix preparation The drainage and aeration layer is made by uniformly mixing coarse river sand and perlite in a 7:3 volume ratio, with a thickness of 9cm. The rooting induction layer is made by uniformly mixing humus and vermiculite in a 5:5 volume ratio, with a thickness of 11cm, and adding 0.1% seaweed extract. The water-retaining and moisture-proof layer is made by uniformly mixing fine sand and coconut coir in a 6:4 volume ratio, with a thickness of 5.5cm. The slow-release regulating layer, by mass percentage, consists of 45% biochar, 20% zeolite, 5% chitosan, 3% sodium alginate, 1% compound antibacterial substance, 2% water-soluble fertilizer retention factor, 1% aeration improver, and 2% calcium chloride, with a total weight of 100%. Biochar and zeolite were mixed in a specific ratio and dried in an oven at 105–110°C for 3 hours. After pulverization, the mixture was passed through a 90-mesh sieve to obtain a porous carrier with well-developed pores. Chitosan and sodium alginate were then added to deionized water at 35°C and stirred at 200 rpm for 40 minutes until completely dissolved, forming a uniform and transparent composite sol. Composite antibacterial substances, water-soluble fertilizer retention factors, and air permeability improvers were added to the composite sol and stirred for 15 minutes until uniformly mixed. The pretreated porous carrier was then added and soaked for 3 hours to ensure that the functional components were fully adsorbed into the pores of the carrier. A 1%–3% calcium chloride solution was slowly added dropwise as a crosslinking agent while stirring. The mixture was allowed to stand at room temperature for 1–2 hours to solidify, forming a flexible slow-release control layer. Finally, the solidified slow-release control layer was dried, with the moisture content controlled at 20%, and directly laid on the bottom layer of the gradient matrix with a thickness controlled at 2 cm, allowing it to naturally adhere to the gradient matrix.

[0026] Spray 0.5% carbendazim solution onto the mixed substrate at a rate of 12L per cubic meter of substrate. After stirring evenly, cover with plastic film and seal for sterilization for 4 days. After sterilization, uncover the film and ventilate for 1.5 days. Adjust the substrate pH to 6.8, bulk density to 0.9g / cm³, and porosity to 58%, and set aside for later use.

[0027] 4. Cuttings propagation The cuttings were taken on July 10th. Holes were made in the disinfected seedbed at a spacing of 9cm between plants and 11cm between rows, with the hole diameter slightly larger than the diameter of the cuttings. The treated cuttings were then inserted into the gradient substrate at a depth of 1 / 2 of the cutting length, with the base of the cuttings located in the middle rooting induction layer. After insertion, the substrate was compacted, and the cuttings were immediately watered thoroughly. 0.05% amino oligosaccharide was added to the water.

[0028] 5. Dynamic closed-loop coordinated regulation Miniature sensors were installed in the seedling shed to monitor stomatal conductance of leaves and electrical conductivity at the base of cuttings in real time. Geothermal heating was used to maintain a constant substrate temperature of 23℃, and an automatic spraying system operated at an adaptive rhythm. During the initial cutting stage (0–7 days), stomatal conductance was monitored at 150–200 mmol / m·s, and electrical conductivity at the base of cuttings was monitored at 0.8–1.0 mS / cm. Spraying intervals were 8 minutes, shading was 80%, and ventilation was conducted twice daily, at 9:00 AM and 5:00 PM, for 18 minutes each time, with the temperature controlled at 22℃ during ventilation. During the root primordia development stage (8–20 days), stomatal conductance was monitored at 200–250 mmol / m·s, and electrical conductivity at the base of cuttings was monitored at 1.0–1.2 mS / cm. When the light intensity was reduced to mS / cm, the spray interval was adjusted to 7 minutes, the shading rate was reduced to 70%, and the ventilation parameters remained unchanged. When the cuttings entered the root growth period (after 21 days), the stomatal conductance of the leaves was maintained at 250–300 mmol / m·s and the electrical conductivity at the base of the cuttings was maintained at 1.2–1.5 mS / cm. The spray interval was adjusted to 10 minutes and gradually reduced to full light, while the ventilation parameters remained unchanged.

[0029] 6. Post-maintenance Once the cuttings have entered the root growth stage, apply a special stress-resistant fertilizer containing 20% ​​phosphorus, 15% potassium, and 5% seaweed extract, diluted 600 times, by foliar spraying once a month for two consecutive months. Spray with a 0.3% carbendazim solution every 8 days after cutting, for two consecutive months. Weed manually in a timely manner during this period. About 3 months after cutting, when the seedlings are growing steadily, transplant them to their final location.

[0030] In this embodiment, the survival rate of Forsythia suspensa cuttings was 95.7%, the average root length of the seedlings was 9.3 cm, the number of roots per plant was 14, the root system effectiveness index was 5.32, the rot rate was 0.3%, the seedlings grew vigorously and had no obvious diseases; the transplant survival rate was 96.2%, and the cold and drought resistance was significantly better than that of seedlings cultivated by existing technologies.

[0031] Example 2 1. Selection of cuttings Select healthy, disease-free, 3-year-old Forsythia fruiting mother trees, collect the current year's sun-facing semi-lignified fruiting branches from the outer periphery of the canopy, and cut the middle section of the branches as cuttings. The cuttings should be 8cm long, 0.3cm in diameter, retain 2 plump buds, and have 1 dormant bud at the base of the cutting.

[0032] 2. Cutting treatment Make a 45° angled cut below a node on the lower part of the cutting, and a straight cut on the upper part, 0.5 cm from the apical bud. Remove all lower leaves, leaving the top two leaflets, which are then cut off by half. The base of the cutting should be smooth and undamaged. Prepare a triple compound treatment solution containing 250 mg / L indolebutyric acid, 15 mg / L salicylic acid, and 60 mg / L proline. Immerse the base of the cutting (3 cm) in the treatment solution at 21°C in the dark for 2.5 hours, stirring every 30 minutes during the soaking process. After soaking, allow the base of the cutting to air dry for 10 minutes before use.

[0033] The gradient matrix was prepared using the same process as in Example 1.

[0034] 4. Cuttings propagation The cuttings were taken on July 5th. Holes were made in the disinfected seedbed at a spacing of 8cm between plants and 10cm between rows, with the hole diameter slightly larger than the diameter of the cuttings. The treated cuttings were then inserted into the gradient substrate at a depth of 1 / 2 of the cutting length, with the base of the cutting located in the middle rooting induction layer. After insertion, the substrate was compacted, and the cuttings were immediately watered thoroughly. 0.05% amino oligosaccharide was added to the water.

[0035] 5. Dynamic closed-loop coordinated regulation Miniature sensors were installed in the seedling shed to monitor stomatal conductance of leaves and electrical conductivity at the base of cuttings in real time. Geothermal heating was used to maintain a constant substrate temperature of 22℃, and an automatic spraying system operated at an adaptive rhythm. During the initial cutting stage (0–7 days), stomatal conductance was monitored at 150–200 mmol / m·s, and electrical conductivity at the base of cuttings was monitored at 0.8–1.0 mS / cm. Spraying was done every 10 minutes, with 80% shading. Ventilation was performed once daily before 10:00 AM for 15 minutes, with the temperature controlled at 20℃ during ventilation. During the root primordia development stage (8–20 days), stomatal conductance was monitored at 200–250 mmol / m·s, and electrical conductivity at the base of cuttings was monitored at 1.0–1.2 mS / cm. When the light intensity was reduced to mS / cm, the spray interval was adjusted to 8 minutes, the shading rate was reduced to 70%, and the ventilation parameters remained unchanged. When the cuttings entered the root growth period (after 21 days), the stomatal conductance of the leaves was maintained at 250–300 mmol / m·s and the electrical conductivity at the base of the cuttings was maintained at 1.2–1.5 mS / cm. The spray interval was adjusted to 12 minutes and gradually reduced to full light, while the ventilation parameters remained unchanged.

[0036] 6. Post-maintenance Once the cuttings have entered the root growth stage, apply a special stress-resistant fertilizer containing 20% ​​phosphorus, 15% potassium, and 5% seaweed extract. Apply 20g per square meter by fertigation, once a month for two consecutive months. Spray with a 0.3% carbendazim solution every 7 days after cutting, for two consecutive months. Weed regularly during this period. About 3 months after cutting, when the seedlings are growing steadily, transplant them to their final location.

[0037] In this embodiment, the survival rate of Forsythia suspensa cuttings was 95.1%, the average root length of the seedlings was 8.8 cm, the number of roots per plant was 13, the root system effectiveness index was 5.18, the rot rate was 0.4%, the seedlings grew well, and the disease incidence rate was less than 0.5%; the transplant survival rate was 95.8%, and the stress resistance was significantly improved.

[0038] Example 3 1. Selection of cuttings Select healthy, disease-free, 3-year-old Forsythia fruiting mother trees, collect the current year's sun-facing semi-lignified fruiting branches from the outer periphery of the canopy, and cut the middle section of the branches as cuttings. The cuttings should be 10cm long, 0.5cm in diameter, retain 2 plump buds, and have 1 dormant bud at the base of the cutting.

[0039] 2. Cutting treatment Make a 45° angled cut below a node on the lower part of the cutting, and a straight cut on the upper part, 0.8 cm from the apical bud. Remove all lower leaves, leaving one small leaf at the top, which is then cut off by half. The base of the cutting should be smooth and undamaged. Prepare a triple compound treatment solution containing 250 mg / L indolebutyric acid, 15 mg / L salicylic acid, and 60 mg / L proline. Immerse the base of the cutting (4 cm) in the treatment solution and soak at 23°C in the dark for 2.5 hours, stirring every 30 minutes during the soaking process. After soaking, allow the base of the cutting to air dry for 15 minutes before use.

[0040] 3. Gradient matrix preparation Same preparation process as in Example 1 4. Cuttings propagation The cuttings were taken on July 15th. Holes were made in the disinfected seedbed at a spacing of 10cm between plants and 12cm between rows, with the hole diameter slightly larger than the diameter of the cuttings. The treated cuttings were then inserted into the gradient substrate at a depth of 2 / 3 of the cutting length, with the base of the cuttings located in the middle rooting induction layer. After insertion, the substrate was compacted, and the cuttings were immediately watered thoroughly. 0.05% amino oligosaccharide was added to the water.

[0041] 5. Dynamic closed-loop coordinated regulation Miniature sensors were installed in the seedling shed to monitor leaf stomatal conductance and cutting base electrical conductivity in real time. Geothermal heating was used to maintain a constant substrate temperature of 24℃, and an automatic spraying system operated at an adaptive rhythm. During the initial cutting stage (0–7 days), leaf stomatal conductance was monitored at 150–200 mmol / m·s, and cutting base electrical conductivity at 0.8–1.0 mS / cm. Spraying intervals were 5 minutes, shading rate was 80%, and ventilation was conducted once daily after 4 PM for 20 minutes, with the temperature controlled at 25℃. During the root primordia development stage (8–20 days), leaf stomatal conductance was monitored at 200–250 mmol / m·s, and cutting base electrical conductivity at 1.0–1.2 mS / cm. Spraying intervals were adjusted to 6 minutes, shading rate was reduced to 70%, and ventilation parameters remained unchanged. During the root growth stage (after 21 days), leaf stomatal conductance was monitored at 250–300 mmol / m·s. The electrical conductivity at the base of the cuttings was maintained at 1.2–1.5 mS / cm, the spraying interval was adjusted to 9 minutes, and the exposure was gradually reduced to full sunlight, while the ventilation parameters remained unchanged.

[0042] 6. Post-maintenance Once the cuttings have entered the root growth stage, apply a special stress-resistant fertilizer containing 20% ​​phosphorus, 15% potassium, and 5% seaweed extract, diluted 800 times, by foliar spraying, once a month for two consecutive months. Spray with a 0.3% carbendazim solution every 10 days after cutting, for three consecutive months. Weed regularly during this period. About three months after cutting, when the seedlings are growing steadily, transplant them to their final location.

[0043] In this embodiment, the survival rate of Forsythia suspensa cuttings was 95.9%, the average root length of the seedlings was 9.5cm, the number of roots per plant was 14, the root system effectiveness index was 5.38, the rot rate was 0.2%, the seedlings grew vigorously and there were no diseases; the transplant survival rate was 96.5%, and the seedlings showed outstanding resistance to cold, drought and pests.

[0044] Comparative Example 1: Conventional Static Cuttings The selection of cuttings, substrate, cutting treatment, and post-treatment management were all the same as in Example 1, except that the dynamic closed-loop collaborative control was changed to "static fixed parameter control", that is, the spraying interval was fixed at 8 minutes, the substrate temperature was constant at 23°C, the shading rate was 80%, and ventilation was carried out twice a day, without real-time monitoring and adaptive adjustment; the results showed that the cutting survival rate was 81.3%, the average root length of the seedlings was 7.2 cm, the number of roots per plant was 9, the rot rate was 6.7%, the transplant survival rate was 82.5%, and the rooting time was 30 days.

[0045] Comparative Example 2: Without the addition of a slow-release control layer Only three layers of gradient substrate were retained. The selection, treatment, cutting operation, post-operative care, and environmental parameters of the cuttings were completely consistent with those in Example 1. Only the bottom slow-release regulation layer of the substrate was missing. The results showed that the cutting survival rate was 79.2%, the average root length of the seedlings was 7.2 cm, the number of roots per plant was 8, the rot rate of cuttings was 7.8%, the transplant survival rate was 81.1%, and the rooting time was 33 days.

[0046] Comparative Example 3: Existing Best Forsythia Cutting Propagation Technique Select one-year-old common Forsythia suspensa vegetative branches, non-fruiting branches, and collect semi-lignified branches from the inner canopy, regardless of whether they are facing the sun or shade. Cuttings should be 8–10 cm long, with no diameter control, and no basal dormant buds are required; only two buds should be retained. Use only 250 mg / L indolebutyric acid (IBA) as a single rooting agent. Roughly prune the cuttings, without controlling the angle or smoothness. Soak the cuttings naturally at room temperature for 2.5 hours. After soaking, insert them directly into the soil. Use a readily available, simple three-layer substrate: gravel + coarse river sand + river sand. Only routine sun-drying and disinfection are required. The insertion time is not fixed; any season is suitable. Insert the cuttings directly at the standard density. Use plain water for initial rooting, without adding amino oligosaccharides. Use static, fixed parameters: fixed spray interval: 8 minutes / time; substrate temperature: room temperature, no temperature control; shading rate: 75%–80% throughout; ventilation: once daily. Later, apply conventional NPK compound fertilizer and conduct disease control and routine management.

[0047] The results showed that the cutting survival rate was 82.1%, the average root length of the seedlings was 7.3 cm, the number of roots per plant was 9, the rot rate of the cuttings was 6.2%, the transplant survival rate was 83.1%, and the rooting time was 29 days.

[0048] Table 1 shows the experimental results of Example 1 and Comparative Examples 1-3. Analysis of experimental results: As shown in the table above, all indicators of the control groups were significantly worse than those of Example 1 of the present invention, which fully demonstrates that the complete whole-process synergistic seedling system of dynamic closed-loop synergistic regulation and multi-layer gradient matrix can further improve the survival rate of Forsythia suspensa cuttings.

Claims

1. A method for improving the survival rate of Forsythia suspensa cuttings, characterized in that, Includes the following steps: S1: Select fruiting mother trees of Forsythia suspensa, collect semi-lignified branches of the current year as cuttings, and retain plump buds; S2: Soak the cuttings in a rooting agent compound treatment solution and then air dry them for later use; S3: Insert the prepared cuttings into the gradient substrate and water thoroughly after planting; S4: Real-time monitoring of leaf stomatal conductance and base electrical conductivity of cuttings, adaptive closed-loop adjustment of substrate temperature, spraying frequency, shading rate and ventilation according to the physiological thresholds of different stages of rooting of Forsythia suspensa tender branches. S5: Apply stress-resistant fertilizer according to the physiological state of the cuttings, and carry out disease prevention and control and daily management.

2. The method for improving the survival rate of Forsythia suspensa cuttings according to claim 1, characterized in that, In the selection of cuttings, the fruiting mother trees of Forsythia are 3-year-old plants. The middle section of the current year's semi-lignified fruiting branches on the outer periphery of the canopy facing the sun is collected as cuttings. The cuttings are 8-10cm long and 0.3-0.5cm in diameter, retaining 2 plump buds and 1 dormant bud at the base.

3. The method for improving the survival rate of Forsythia suspensa cuttings according to claim 1, characterized in that, In step S2, the cuttings are also pruned and the leaves are treated; the rooting agent compound treatment solution specifically includes a compound solution of indolebutyric acid, salicylic acid and proline.

4. The method for improving the survival rate of Forsythia suspensa cuttings according to claim 1, characterized in that, The gradient substrate of S3 is a gradient substrate with different functions, specifically including a drainage and aeration layer, a rooting induction layer and a water retention and anti-drying layer. The substrate is prepared for use after being disinfected.

5. The method for improving the survival rate of Forsythia suspensa cuttings according to claim 1, characterized in that, The bottom layer of the gradient matrix also includes a sustained-release regulation layer, which is specifically composed of porous biochar, chitosan-based responsive gel and nano-antibacterial particles.

6. The method for improving the survival rate of Forsythia suspensa cuttings according to claim 1, characterized in that, In the cutting operation described in S3, the cutting depth is 1 / 2–2 / 3 of the cutting length and the base of the cutting is located in the middle rooting induction layer.

7. The method for improving the survival rate of Forsythia suspensa cuttings according to claim 1, characterized in that, The adaptive closed-loop adjustment of S4 is specifically adjusted according to the different stages of rooting of Forsythia suspensa tender branches, using the physiological thresholds of leaf stomatal conductance and cutting base electrical conductivity corresponding to that stage.

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