Method and system for promoting growth of cherry root system

Abstract

The invention provides a method and system for promoting growth of cherry root systems, and the method comprises the following steps: S1, mixing nanocellulose with an organic mixed ion electron conductor, and adding a conductive electrode; s2, directionally freezing to form an electronic soil matrix with a porous structure; s3, selecting a cherry rootstock, reserving at least two bud nodes, and soaking and disinfecting a base part by using a 0.05-0.15% KMnO4 solution; s4, inserting the cutting slips into an electronic soil matrix, applying 0.3-0.8 V direct-current voltage, and dynamically adjusting voltage parameters. According to the method, the electronic soil matrix is used for replacing water culture or soil culture, the electronic soil matrix of a porous structure is formed through mixing treatment of the nanocellulose and the organic mixed ion electronic conductor, and active growth of meristem of the root tip is promoted. The gradient pore design simulates the natural soil level, so that the cherry root system distribution better meets the water and fertilizer absorption requirement, the root system development is optimized, and the gradient designed porous structure is matched with the growth path of the cherry rootstock root system, so that the lateral root density is improved, and the xylem conduit differentiation period is shortened.

Description

Technical Field

[0001] The invention relates to the technical field of plant cultivation, and in particular to a method and a system for promoting the growth of cherry root systems. Background Art

[0002] As the core technology of asexual plant reproduction, cuttings play an important role in forest seedling cultivation due to their advantages such as simple operation, high reproduction coefficient and strong genetic stability. Hardwood cuttings and softwood cuttings form a complementary technical system due to the differences in material characteristics, especially showing unique value in the cultivation of woody rootstocks such as cherries. With the development of modern facility agriculture, the application of automatic spraying and temperature control systems has significantly improved the accuracy of cutting environment control, and the popularization of artificial synthetic plant growth regulators is regarded as the key to technological breakthroughs.

[0003] However, the current technology system is caught in a dilemma: on the one hand, there are many types of plant growth regulators on the market and their mechanisms of action are unclear. The blind use of high-concentration hormones leads to frequent problems such as physiological disorders of cuttings and loss of germplasm resources. On the other hand, over-reliance on chemical regulation has aggravated the burden on the ecological environment, and the destructive effects of residual hormones on soil microbial communities are becoming increasingly apparent. Although physical root-promoting technologies such as electrical stimulation have shown initial potential, existing equipment has technical blind spots such as non-renewable electrode materials and mismatch between stimulation modes and plant bioelectric rhythms, making it difficult to meet the urgent needs of woody plants such as cherry rootstocks for precise and ecological seedling cultivation. This contradiction has become increasingly prominent under the dual demands of germplasm resource protection and large-scale production, and it is urgent to develop a new generation of root-promoting technology systems that take into account biocompatibility, targeted action, and operational universality. Summary of the invention

[0004] One purpose of the present invention is to break through the excessive reliance of traditional cutting technology on hormones, and to provide an environmentally friendly, precisely regulated physical root-promoting alternative. Furthermore, the present invention provides a method for promoting the growth of cherry roots.

[0005] Another object of the present invention is to provide a system for promoting root growth of cherries.

[0006] In particular, the present invention provides a method for promoting the root growth of cherries, comprising the following steps:

[0007] S1. Mixing nanocellulose with an organic mixed ionic electronic conductor and adding a conductive electrode;

[0008] S2. Directed freezing to form a porous electronic soil matrix;

[0009] S3. Select cherry rootstock, retain at least 2 bud nodes, and use 0.05-0.15% KMnO at the base. 4 Solution immersion disinfection;

[0010] S4. Insert the cuttings into the electronic soil matrix, apply a DC voltage of 0.3-0.8V, and dynamically adjust the voltage parameters.

[0011] Further, the organic mixed ion-electron conductor is PEDOT:PSS;

[0012] The conductive electrode comprises carbon fiber bundles, metal mesh or conductive polymer foam and has mixed ion-electron conduction characteristics at a voltage of 0.1-1V.

[0013] Furthermore, the porous structure satisfies:

[0014] a) Surface area (0-2 mm): pore size 20-50 μm, porosity 75-80%;

[0015] b) Root development zone (2-10 mm): pore size 100-200 μm, porosity 85-90%.

[0016] Furthermore, before step S2, the method further includes:

[0017] a) Cut 1-2 year old cherry scions and bury them in wet sand before winter freezing;

[0018] b) Cut cherry scions on an inclined surface in spring, and dip them in a 10-20 ppm rooting powder solution;

[0019] Furthermore, in step S3, the voltage parameters are dynamically adjusted by monitoring the concentrations of nitrate and ammonium ions.

[0020] Furthermore, the dynamically adjusting voltage parameters includes:

[0021] When the root nitrate concentration is less than 5mM, the voltage is increased to 0.5-0.8V to enhance the activity of root nitrate reductase;

[0022] When the canopy nitrate / ammonium ratio is greater than 3, the voltage is reduced to 0.3-0.5 V to promote nutrient transport to the aboveground part.

[0023] Furthermore, when the root ammonium concentration is detected to be greater than 2 mM, the following coordinated actions are triggered:

[0024] The voltage was switched to a pulse mode (0.5 V / 10 Hz, 30% duty cycle).

[0025] In particular, the present invention also discloses a system for promoting the growth of cherry root system, which is used to implement a method for promoting the growth of cherry root system, comprising:

[0026] An electronic soil matrix composed of nanocellulose, organic mixed ionic electronic conductors and conductive electrodes, wherein the organic mixed ionic electronic conductors account for 8-15% by mass;

[0027] a container for containing the electronic soil matrix;

[0028] A conductive electrode is inserted into the electronic soil matrix and a power source is connected to the conductive electrode.

[0029] Furthermore, the conductive electrodes are arranged along the axial direction.

[0030] Furthermore, it also includes a nitrate-nitrogen metabolism monitoring unit for detecting nitrogen metabolism of cherry rootstock.

[0031] In the present invention, an electronic soil matrix is ​​used instead of hydroponics or soil culture, and a porous electronic soil matrix is ​​formed by mixing nanocellulose with an organic mixed ion electronic conductor. The surface layer of the electronic soil matrix (pore size 20-50 μm) effectively locks water and nutrients to prevent evaporation loss; the root development zone (pore size 100-200 μm) provides sufficient oxygen diffusion space to promote the active growth of root tip meristems. The gradient pore design simulates the natural soil layer, so that the distribution of cherry roots is more in line with the needs of water and fertilizer absorption, the root development is optimized, and the gradient porous structure matches the root growth path of the cherry stock, so that the lateral root density is increased and the xylem vessel differentiation cycle is shortened.

[0032] In the present invention, a low voltage of 0.3-0.8V is used to stimulate the mixed conduction characteristics of organic mixed ion-electron conductors, and an integrated electronic soil matrix is ​​used to replace the traditional electrode arrangement, thereby simplifying the complexity of the equipment, reducing the cost of seedling cultivation, and requiring no professional electrochemical operation skills.

[0033] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0035] Figure 1 is a schematic diagram of steps of a method for promoting root growth of cherries according to an embodiment of the present invention;

[0036] Figure 2 Schematic diagram of a system for promoting root growth of cherries according to an embodiment of the present invention.

[0037] In the figure:

[0038] 1-electronic soil matrix; 2-container; 3-conductive electrode; 4-pulse power supply. DETAILED DESCRIPTION

[0039] Example 1

[0040] like Figure 1 As shown, this embodiment provides a method for promoting the root growth of cherries, comprising the following steps:

[0041] S1. Mixing nanocellulose with an organic mixed ionic electronic conductor and adding a conductive electrode;

[0042] S2. Directed freezing to form a porous electronic soil matrix;

[0043] S3. Select cherry rootstock, retain at least 2 bud nodes, and use 0.05-0.15% KMnO at the base. 4 Solution immersion disinfection;

[0044] S4. Insert the cuttings into the electronic soil matrix, apply a DC voltage of 0.3-0.8V, and dynamically adjust the voltage parameters.

[0045] According to one embodiment of the present invention, nanocellulose uses carboxymethylated nanocellulose (NFC), organic mixed ion-electronic conductor uses PEDOT:PSS, and conductive electrode uses carbon fiber bundle. Wherein, in step S1 and step S2, the electronic soil matrix is ​​prepared as follows: PEDOT:PSS aqueous solution (PH1000, 1.3wt%), carboxymethylated nanofibrillated cellulose (NFC, 1wt%) and crosslinking agent GOPS (97wt%) are mixed in a mass ratio of 1:1:0.2, and homogenized at 10000rpm for 10 minutes using an IKA ULTRA-TURRAX S25 disperser to form a uniform slurry. 0.093g of carbon fiber (PAN-CF, diameter 7μm, average length 12.5cm) is randomly dispersed in a polystyrene conical mold (volume 30mL, top diameter 2cm, bottom diameter 1cm), and then the mixed slurry is injected and vibrated to remove bubbles. After the mold was frozen at -20°C for 24 hours, it was transferred to a freeze dryer (-50°C, 200 μbar) for freeze drying for 72 hours to obtain an electronic soil matrix with a porous structure having a porosity of 75-90% and a crystallinity of ≤15%.

[0046] According to one embodiment of the present invention, after obtaining the porous structured electronic soil matrix, the porous structured electronic soil matrix is ​​also placed in a 140°C vacuum oven for annealing for 30 minutes to complete thermal crosslinking, and then treated with DMSO vapor on a 60°C hot plate for 24 hours [1 mL of dimethyl sulfoxide (DMSO) is pre-added in the culture dish]. Characterized by SEM and X-ray micro-CT, the surface pore size of the porous structured electronic soil matrix is ​​20-50 μm (porosity 75-80%), the deep pore size is 100-200 μm (porosity 85-90%), and the carbon fibers are evenly distributed without agglomeration.

[0047] According to one embodiment of the present invention, before step S3, the cherry rootstock needs to be pretreated. During the pretreatment, a one-year-old scion (diameter 6-8 mm) is cut, and wet sand (water content 35%) is buried in a 4°C cold storage for wintering. It is taken out in spring, rinsed with clean water and dried, and cut into 18 cm long cuttings, the upper end is cut flat (1 cm away from the top bud), the lower end is cut at 45°, two full leaf buds are retained, and the lower leaves are removed. Soaked in 0.1% KMnO 4 Solution for 15 minutes, rinse with water 3 times, and immerse the beveled end in 15 ppm IBA rooting powder solution at 25±2℃ for 5 hours.

[0048] According to one embodiment of the present invention, the power supply adopts a pulse power supply, outputs a square wave with a pulse width of 100ms and an interval of 300ms, inserts the treated cuttings vertically into the electronic soil matrix, applies a 0.45V DC voltage, and continuously stimulates for 72 hours in an environment with a temperature of 25°C and a humidity of 80%. When the impedance phase angle Δθ>15° (about the 5th day), it is switched to a 0.5V pulse mode (duty cycle 15%, frequency 0.1Hz) and automatically starts atomization water replenishment (5mL of water replenishment each time, EC value 1.8mS / cm) when the moisture content of the matrix is ​​lower than 38%.

[0049] According to one embodiment of the present invention, in the above-mentioned step S4, when dynamically adjusting the voltage, first insert the cuttings into the electronic soil matrix and turn on the pulse power supply. The rhizosphere nitrate and ammonium concentrations are monitored by spectrophotometry. When the root nitrate concentration drops to 4mM, the voltage is increased to 0.7V for 48 hours. When the canopy nitrate / ammonium ratio is greater than 3, the voltage is reduced to 0.4V to promote the transport of nutrients to the aboveground part. If the root ammonium concentration exceeds 2mM, switch to pulse mode (0.5V / 10Hz, duty cycle 30%). It can be understood that the canopy refers to the branch and leaf system of the aboveground part of the plant, including leaves, stems and branch structures. Its main functions are photosynthesis, transpiration and gas exchange. In nitrogen metabolism, the canopy is responsible for further reducing the nitrate absorbed by the roots into ammonium and synthesizing amino acids and proteins. The root system is an organ network of the underground part of the plant, including taproots, lateral roots and root hairs, responsible for absorbing water and mineral nutrients (such as nitrates, ammonium salts, and potassium salts). The root system is the initial place of nitrogen metabolism, where nitrates are converted into nitrites by nitrate reductase and then further converted into ammonium.

[0050] According to one embodiment of the present invention, by monitoring the ammonium and nitrate concentrations in the root system and canopy, the nitrogen metabolism pathway is adjusted in combination with voltage stimulation to optimize the nitrogen allocation efficiency. The specific strategy is as follows:

[0051] (1) When the root nitrate concentration is low (<5mmol / L), root metabolism needs to be promoted. A common phenomenon at this time is that the supply of nitrate is insufficient, and the plant preferentially completes nitrogen metabolism in the roots, reducing the energy consumption of transporting it to the crown. At this time, the voltage needs to be increased (0.5-0.8V) to enhance the electric field-driven ion migration and promote the flow of nitrate into the root cell membrane. Activate nitrate reductase (NR). Electrical stimulation increases nitrate reductase activity and accelerates the conversion of nitrate → nitrite → ammonium. Root ammonium accumulation is used to synthesize amino acids and stimulate root hair proliferation.

[0052] (2) When the canopy nitrate / ammonium ratio is high (>3), root metabolism needs to be inhibited. A common phenomenon at this time is that excessive nitrate transported to the canopy will lead to excess nitrogen in the leaves, inhibiting the distribution of photosynthetic products to the roots. Reducing the voltage (0.3-0.5V) weakens the root electric field, limits the reduction of nitrate in the roots, promotes the transport of nitrate to the canopy, drives nitrate upward along the xylem through the electroosmotic effect, reduces the metabolic burden of the roots, improves the efficiency of protein synthesis by canopy ammonium roots, and stabilizes the root biomass / canopy biomass ratio in the ideal range (0.8-1.2).

[0053] (3) When the root ammonium concentration is too high (>2mmol / L), an emergency response is required. At this time, excessive ammonium causes the release of hydrogen ions, leading to rhizosphere acidification (pH<5.5), inhibiting nutrient absorption. At this time, it is necessary to switch the pulse voltage (0.5V / 10Hz, duty cycle 30%). Intermittent stimulation reduces continuous ammonium accumulation, alleviates hydrogen ion release, stabilizes the root pH at 6.0-6.5, and reduces the root rot rate caused by ammonium toxicity from 25% to 8%.

[0054] Experimental results (30 days of cultivation):

[0055] Test items This embodiment group Traditional rock wool substrate hydroponic group Rooting rate (%) 93.6 67.2 Average root length (cm) 14.2 5.8 Lateral root density (roots / cm) 8.7 3.1 Xylem vessel diameter (μm) 42.3 28.7

[0056] (Note: The data in this example are based on 3 independent repeated experiments, n=50).

[0057] Comparative Example 1

[0058] In this comparative example, the traditional hormone-dependent cutting seedling experiment was compared. The traditional seedling matrix was a perlite-vermiculite matrix, and its matrix composition was perlite: vermiculite = 1:1 (volume ratio), sterilized at 121°C with high pressure steam for 30 minutes, and no conductive material was added. The cuttings were treated with the same variety and material collection time as in the embodiment, and the base of the cuttings was soaked in 1500ppm IBA solution for 15 seconds (IBA solution is a commercially available strong rooting powder solution), and the same sand storage pretreatment was used as in Example 1. The seedlings were raised by relying on an automatic spray system, and the humidity was maintained at 80%, with the same light (12000Lux) and temperature (25°C).

[0059] Experimental results (30 days of cultivation):

[0060] Test items Embodiment 1 of the present invention Comparative Example 1 Rooting rate (%) 93.6 58.4* Average root length (cm) 14.2 7.3 Lateral root density (roots / cm) 8.7 3.0 Xylem vessel diameter (μm) 42.3 25.3

[0061] Note: * In the traditional group, 23% of the cuttings suffered from bud necrosis due to hormone burns

[0062] In comparative example 1, high concentration of IBA treatment resulted in abnormal cell membrane permeability, and the lateral roots of the traditional root structure method were mostly clustered and short and thick, which reduced the adaptability to transplantation.

[0063] Example 2

[0064] like Figure 2 As shown, the present invention also discloses a system for promoting the growth of cherry root system, which is used to implement a method for promoting the growth of cherry root system, comprising:

[0065] An electronic soil matrix 1 composed of nanocellulose, an organic mixed ionic electronic conductor and a conductive electrode, wherein the organic mixed ionic electronic conductor accounts for 8-15% by weight;

[0066] A container 2 for containing the electronic soil matrix;

[0067] A conductive electrode 3 is inserted into the electronic soil matrix and a pulse power source 4 is connected to the conductive electrode.

[0068] According to one embodiment of the present invention, the preparation method of the electronic soil matrix 1 has been given in Example 1. In this embodiment, a barrel-type container is used as the container 2 for holding the electronic soil matrix, and a pulse power supply 4 is used. The pulse power supply 4 is connected to the conductive electrode 3 of the electronic soil matrix axially inserted into the barrel-type container through a wire. In this embodiment, the nitrate-nitrogen metabolism monitoring unit for detecting nitrogen metabolism of cherry rootstock refers to a complete set of spectrophotometric detection equipment, which is a common technology in the field and will not be repeated here. It can be understood that the nitrate-nitrogen metabolism monitoring unit and the pulse power supply in this embodiment are both manually operated.

[0069] According to one embodiment of the present invention, the porous structure of the electronic soil substrate 1 includes two layers, wherein the first layer is the surface area, with a thickness of 0-2mm, a pore size of 20-50μm, and a porosity of 75-80%; the second layer is below the first layer, which is the root development area, with a pore size of 100-200μm and a porosity of 85-90%. A pore gradient is formed between the two layers. The first layer effectively locks in water and nutrients to prevent evaporation loss; the second layer provides sufficient oxygen diffusion space to promote the active growth of root tip meristems. The gradient pore design simulates the natural soil layer, so that the distribution of cherry roots is more in line with the needs of water and fertilizer absorption, and the root development is optimized. The gradient porous structure matches the root growth path of the cherry stock, increases the density of lateral roots, and shortens the differentiation cycle of the xylem vessels.

[0070] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the content disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all these other variations or modifications.

Claims

1. A method for promoting root growth of cherries, characterized in that: The following steps are involved: S1. Mixing nanocellulose with an organic mixed ionic electronic conductor and adding a conductive electrode; S2. Directed freezing to form a porous electronic soil matrix; S3. Select cherry rootstock, retain at least 2 bud nodes, and soak the base in 0.05-0.15% KMnO4 solution for disinfection; S4. Insert the cuttings into the electronic soil matrix, apply a DC voltage of 0.3-0.8V, and dynamically adjust the voltage parameters.

2. The method for promoting root growth of cherries according to claim 1, characterized in that: The organic mixed ion-electron conductor is PEDOT:PSS; The conductive electrode comprises carbon fiber bundles, metal mesh or conductive polymer foam and has mixed ion-electron conduction characteristics at a voltage of 0.1-1V.

3. The method for promoting root growth of cherries according to claim 1, characterized in that: The porous structure satisfies: a) Surface area (0-2 mm): pore size 20-50 μm, porosity 75-80%; b) Root development zone (2-10 mm): pore size 100-200 μm, porosity 85-90%.

4. The method for promoting root growth of cherries according to claim 1, characterized in that: Before step S2, the method further includes: a) Cut 1-2 year old cherry scions and bury them in wet sand before winter freezing; b) In spring, cut the cherry scions on an inclined surface, and dip them in a 10-20 ppm rooting powder solution.

5. The method for promoting root growth of cherries according to claim 1, characterized in that: In step S3, the voltage parameters are dynamically adjusted by monitoring the concentrations of nitrate ions and ammonium ions.

6. The method for promoting root growth of cherries according to claim 5, characterized in that: The dynamically adjusted voltage parameters include: When the root nitrate concentration is less than 5mM, the voltage is increased to 0.5-0.8V to enhance the activity of root nitrate reductase; When the canopy nitrate / ammonium ratio is greater than 3, the voltage is reduced to 0.3-0.5 V to promote nutrient transport to the aboveground part.

7. The method for promoting root growth of cherries according to claim 5 or 6, characterized in that: When the root ammonium concentration is detected to be > 2 mM, the following coordinated actions are triggered: The voltage was switched to a pulse mode (0.5 V / 10 Hz, 30% duty cycle).

8. A system for promoting root growth of cherries, used for implementing claims 1-7, characterized in that: include: An electronic soil matrix composed of nanocellulose, organic mixed ionic electronic conductors and conductive electrodes, wherein the organic mixed ionic electronic conductors account for 8-15% by mass; a container for containing the electronic soil matrix; A conductive electrode is inserted into the electronic soil matrix and a power source is connected to the conductive electrode.

9. The system for promoting root growth of cherry according to claim 6, characterized in that: The conductive electrodes are arranged along the axial direction.

10. The system for promoting root growth of cherries according to claim 6, characterized in that: Also included is a nitrate-nitrogen metabolism monitoring unit for monitoring nitrogen metabolism in cherry rootstock.

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