A hydroponic root-inducing method for Citrus reticulata and its supporting nutrient solution and application.

Abstract

This invention relates to a hydroponic root-inducing method for *Cinnamomum camphora*, characterized by the following steps: plant pretreatment; hormone-induced root treatment; perlite substrate for root induction transition; mist-controlled humidification environment for root induction; hydroponics; and disease prevention. The hydroponics includes: hydroponics in clean water until secondary lateral roots of a predetermined length are formed, followed by nutrient solution cultivation; the nutrient solution is supplied using a gradient approach. This invention's hydroponic root-inducing method employs a synergistic model of hormone-induced root induction, perlite fixation, and a high-humidity environment, significantly improving the success rate of root induction and avoiding the mortality problem caused by direct hydroponics. Through gradient acclimatization with nutrient solution concentrations, it significantly reduces the incidence of early root tip necrosis and root rot, improving survival rate and root vitality.

Description

Technical Field

[0001] This invention relates to the field of hydroponic technology, and in particular to a method for inducing root growth in hydroponically using *Cinnamomum camphora*, along with a matching nutrient solution and its application. Background Technology

[0002] Kumquat trees are woody ornamental fruit trees characterized by their compact shape, evergreen leaves, and brightly colored fruits. They are widely used for home decoration, garden displays, and festive decorations. To improve aesthetics and simplify daily management, some cultivation practices have begun to explore hydroponics instead of traditional soil cultivation for kumquat trees.

[0003] Compared to herbaceous ornamental plants, kumquats have typical woody native root systems with dense tissue structure, making them more sensitive to changes in water conditions and rhizosphere oxygen levels. Currently, if soil-grown kumquats are directly removed from the soil and placed in water or nutrient solution, root rot, difficulty in new root formation, and plant wilting often occur, making hydroponics unsuccessful.

[0004] For hydroponic applications of citrus plants, existing technologies have attempted to promote rooting by using exogenous hormone treatment, water propagation to induce root growth, or short-term substrate transition. However, these methods generally suffer from low root induction efficiency, limited number of new roots, and insufficient lateral root development, making it difficult to form a stable aquatic root system and thus limiting the continuous growth of the entire plant.

[0005] Meanwhile, citrus plants have large leaf areas and strong transpiration during the root induction stage, making them highly responsive to changes in environmental humidity. Current root induction methods rely on relatively crude humidity control techniques, which can easily lead to water loss and wilting in the early stages of root induction, thereby inhibiting root formation and reducing the success rate of hydroponics. Summary of the Invention

[0006] To address the shortcomings of existing technologies and based on the technical requirements for stable hydroponic cultivation of citrus plants, it is necessary to provide a hydroponic root-inducing method suitable for citrus woody plants, along with a reasonable nutrient solution management system. By coordinating hormone treatment, substrate fixation methods, root-inducing environmental conditions, and nutrient solution supply, aquatic root formation can be promoted, and the hydroponic survival rate can be improved, thereby achieving stable growth of citrus plants under hydroponic conditions.

[0007] This invention provides a method for hydroponic root induction of Citrus reticulata, characterized by comprising the following steps:

[0008] Plant pretreatment; Hormone-induced root treatment: The treated roots of the Citrus cinnabarii were soaked in an exogenous auxin solution; Perlite substrate root induction transition: The cinnabar orange was planted in a transition substrate, which included perlite, to obtain the planted plants; Fogging and humidity-controlled root-inducing environment: The planted plants are placed in a fogging or humidity-controlled environment to induce root growth, resulting in root-inducing plants; the relative humidity of the fogging or humidity-controlled environment is 75-85%, and the temperature is 20-30℃. Hydroponics: The root-inducing plantlets are transferred to a hydroponic planting device for hydroponics; the hydroponics includes: hydroponics in clean water until secondary lateral roots of a predetermined length are formed, followed by nutrient solution culture.

[0009] When the air humidity is low, the large leaf area and strong transpiration of the cinnabar mandarin orange make it very easy for it to experience significant water loss, wilting, and leaf decline in the early stages of root induction, significantly increasing the probability of root induction failure. When the air humidity is too high, it can easily lead to leaf surface water damage and increased risk of disease, while also adversely affecting the root growth rate and health. When root induction is carried out within the air relative humidity control range proposed in this invention, the plant's leaf condition and root formation are both stable and the effect is optimal.

[0010] In one embodiment, the soaking time in the hormone-induced root treatment step is 10-12 hours.

[0011] In one embodiment, the hydroponics includes the following steps: removing the root-inducing plant, removing residual transition substrate, and transferring it to a hydroponic planting device, wherein the hydroponic planting device uses pebbles for planting.

[0012] In one embodiment, the hydroponic planting device includes a hydroponic planting basket.

[0013] In one embodiment, after hydroponics, during the clear water hydroponics and nutrient solution culture stages, when the new root tips have emerged from the bottom hole of the hydroponic planting device, the water level is controlled to submerge 2 / 3 of the length of the new roots and cover 15-30mm above the root tips; when the new roots have not yet emerged from the hole, the water level is controlled to be 5-10mm above the bottom of the hydroponic planting device, and each time water is added, the principle is to immerse 2 / 3 of the new roots in the water.

[0014] In one embodiment, the plant pretreatment includes the following steps: selecting healthy tangerine trees, rinsing them, soaking them in a disinfectant, and air-drying them.

[0015] In one embodiment, the disinfectant comprises a carbendazim wettable powder solution.

[0016] In one embodiment, the disinfectant soaking time is 20-30 minutes.

[0017] In one embodiment, the exogenous auxin includes indolebutyric acid, and the concentration of the exogenous auxin solution is 40~60 mg / L; In the aforementioned mist-controlled root-inducing environment step, the perlite root-inducing period is 50-90 days.

[0018] In one embodiment, during the nutrient solution culture step, the nutrient solution is supplied using an incremental gradient method, as follows: Days 1-15: 20% volume concentration nutrient solution; Days 16-30: 40% volume concentration nutrient solution; Days 31-45: 60% volume concentration nutrient solution; Days 46-60: 80% volume concentration nutrient solution; 61 days and beyond: 100% volume concentration of nutrient solution.

[0019] In one embodiment, the nutrient solution includes solution A, solution B, and solution C; Solution A includes calcium nitrate tetrahydrate and potassium nitrate; the concentration of calcium nitrate tetrahydrate in the nutrient solution is 900~945 mg / L, and the concentration of potassium nitrate is 600~750 mg / L. Solution B comprises ammonium dihydrogen phosphate and magnesium sulfate heptahydrate; the concentration of ammonium dihydrogen phosphate in the nutrient solution is 100~140 mg / L, and the concentration of magnesium sulfate heptahydrate is 480~500 mg / L. Solution C comprises ferric disodium ethylenediaminetetraacetate, boric acid, manganese sulfate tetrahydrate, zinc sulfate heptahydrate, copper sulfate pentahydrate, and ammonium molybdate tetrahydrate. In the nutrient solution, the concentration of ferric disodium ethylenediaminetetraacetate is 30-40 mg / L, the concentration of boric acid is 2.8-2.9 mg / L, the concentration of manganese sulfate tetrahydrate is 2.1-2.2 mg / L, the concentration of zinc sulfate heptahydrate is 0.2-0.3 mg / L, the concentration of copper sulfate pentahydrate is 0.07-0.09 mg / L, and the concentration of ammonium molybdate tetrahydrate is 0.01-0.03 mg / L.

[0020] In one embodiment, the hydroponics includes: changing the water every 3 to 5 days, and after the aquatic roots continue to grow and form secondary lateral roots with a length of ≥2mm, nutrient solution culture is carried out. The pH of the nutrient solution is controlled at 6.0~6.5.

[0021] In one embodiment, disease prevention is also included, which includes: in the misting and humidification root-inducing environment step and in the hydroponic step, whole-plant sterilization treatment is carried out every 14 to 21 days.

[0022] In one embodiment, the whole-plant sterilization treatment employs a rotating agent approach, wherein the agents include: carbendazim wettable powder solution, chlorothalonil solution, or thiophanate-methyl solution.

[0023] In one embodiment, the perlite matrix root-inducing transition step includes the following steps: Fill the bottom of the permeable container with transition substrate, place the cinnabar orange in the center of the container, continue filling with transition substrate until it covers and fixes the root system, and water it.

[0024] In one embodiment, the watering includes: watering thoroughly at first to moisten the substrate, and then watering once every day during the root induction stage to keep the perlite moist but not waterlogged.

[0025] The second aspect of the present invention also provides the nutrient solution used in the above-described hydroponic root-inducing method for Citrus reticulata.

[0026] The third aspect of the present invention also provides the application of the above-mentioned hydroponic root induction method for tangerine or the nutrient solution in the above-mentioned hydroponic root induction method in the hydroponic cultivation of citrus plants.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. Improve hydroponic survival rate: The combined use of hormone-induced rooting, perlite fixation, and high-humidity environment significantly improves the success rate of root induction and avoids the problem of death caused by direct hydroponics.

[0028] 2. Promotes stable aquatic root formation: Compared with direct cultivation using full-concentration nutrient solution, this invention significantly reduces the incidence of early root tip necrosis and root rot through nutrient solution concentration gradient acclimatization, thereby improving survival rate and root vitality. It fosters an aquatic root system adapted to the hydroponic environment, with well-developed lateral roots and strong continuous growth.

[0029] 3. Nutrient solution adapted to the physiological characteristics of Cinnamon: Through gradual concentration acclimatization, the risk of salt stress is reduced, and early adaptability and later growth stability are improved.

[0030] 4. The method is easy to operate and highly adaptable: it does not require a complicated hydroponic system and is suitable for greenhouses, horticultural production and home viewing scenarios. Attached Figure Description

[0031] Figure 1 The image shows the root growth of the stepwise nutrient solution group (nutrient solution supplied in an incremental gradient manner) in Example 1, where the left and right images show the root growth of different plants, respectively. Figure 2 The image shows the root growth of the nutrient solution group (100% volume concentration) in Comparative Example 1, where the left and right images show the root growth of different plants. Detailed Implementation

[0032] This invention provides a hydroponic method for mandarin oranges and a supporting nutrient solution management system. Through exogenous hormone induction, perlite substrate transition fixation, misting humidity control, and phased nutrient solution gradual acclimatization, the root system of mandarin oranges is promoted to stably transform from soil-grown roots to aquatic roots, thereby improving the survival rate and growth stability of hydroponics.

[0033] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0035] Unless otherwise specified, all reagents, materials, and equipment used in this embodiment are commercially available; unless otherwise specified, all test methods are conventional test methods in this field.

[0036] Example 1 This embodiment provides a method for hydroponic root induction of Citrus reticulata, including the following steps: S1: Plant pretreatment: Select healthy cinnamon orange plants, remove weak roots, rotten roots and diseased roots; rinse with clean water to remove surface soil and attached substances, then soak in 800~1000 times carbendazim wettable powder solution for 20~30 minutes to disinfect the root system, and then air dry naturally. S2: Hormone-induced root treatment: The treated roots of Citrus cinnamon were soaked in an exogenous auxin solution for 10-12 hours, preferably indolebutyric acid (IBA) 50 mg / L, to promote root primordia formation and root induction. S3: Rooting transition in perlite substrate: Plant the plant in a permeable container with drainage holes, fill the bottom with about 1 / 3 volume of perlite, place the plant in the center of the container, allow the roots to spread out naturally, and continue to fill with perlite until the roots are covered and fixed; water thoroughly for the first time to moisten the substrate, and water once every day during the rooting stage to keep the perlite moist but not waterlogged. S4: Fog-controlled root-inducing environment: Place the planted plants in a fog-controlled or humidity-controlled environment, with the relative humidity controlled at 75%~85% and the temperature maintained at 20℃~30℃. The perlite root-inducing period is about 50~90 days. S5: Transfer to hydroponics and planting with pebbles: Gently remove the plant after root induction, remove any residual substrate from the root surface to avoid damaging the new roots; transfer the plant to a hydroponic planting basket filled with pebbles, where the pebbles support and fix the root system, creating a good mechanical stability and air-water balance environment. S6: In the initial stage of hydroponics, use clean water for cultivation and change the water every 3 to 5 days. After the aquatic roots continue to grow and form secondary lateral roots with a length of ≥2mm, enter the nutrient solution cultivation stage. During the hydroponic and nutrient solution culture stages, when the new root tips have emerged from the holes at the bottom of the planting basket, the water level should be controlled to submerge about 2 / 3 of the length of the new roots and cover the root tips by 15-30mm. When the new roots have not yet emerged from the holes, the water level should be controlled to be 5-10mm above the bottom of the planting basket, so that the root tips are in a high-humidity environment. As the root system grows, each time water is added, the principle should be that the new roots are submerged in about 2 / 3 of the water. S7: Gradual Acclimatization and Growth Management of Hydroponics and Nutrient Solution: Nutrient solution is supplied using an incremental gradient method, specifically: Days 1-15: 20% volume concentration nutrient solution; Days 16-30: 40% volume concentration nutrient solution; Days 31-45: 60% volume concentration nutrient solution; Days 46-60: 80% volume concentration nutrient solution; Day 61 and beyond: 100% volume concentration nutrient solution; The pH of the nutrient solution should be controlled at 6.0-6.5, and an air layer of 1-3 cm should be maintained to ensure oxygen supply to the roots. S8: Disease prevention: During the root induction and hydroponic acclimatization stage, spray the whole plant with fungicide every 14-21 days, using a rotation of fungicides, including: 800-1000 times carbendazim wettable powder solution, 1000 times chlorothalonil solution or 1000 times thiophanate-methyl solution.

[0037] After transitioning to hydroponics, it is crucial not to use full-concentration nutrient solution (100% volume concentration) directly in the initial stage, as this can easily lead to salt stress and rot in the newly formed roots. The nutrient solution of this invention appropriately increases the Ca content. 2+ With NO3 - The ratio reduces NH4 + The proportions are tailored to the physiological characteristics of the Cinnamon tree's root system, which is sensitive to salt stress and has a high calcium requirement. The nutrient solution used in this embodiment of the invention is specifically designed for the growth period of the Cinnamon tree, and the formula is shown in Table 1: Table 1 Nutrient solution formula (specifically for the growth period of Cinnabar Orange)

[0038] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that the nutrient solution is supplied at full concentration (100% volume concentration), while the other steps are the same as in Example 1.

[0039] Comparative Example 2 Comparative Example 2 was cultivated using a conventional hydroponic method. The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 did not set a root induction transition stage or humidity control conditions, and it did not control the nutrient solution supply method and water level in stages during the initial stage of hydroponics.

[0040] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that perlite is replaced with coconut coir; the other steps are the same as in Example 1.

[0041] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that perlite is replaced with river sand; the other steps are the same as in Example 1.

[0042] Implementation effect evaluation 1. Hormone-induced root In the evaluation of the implementation effect, a comparative experiment was conducted on the concentration of exogenous auxin used in step S2 (25, 50, 75, 100 mg / L), and the results are shown in Table 2.

[0043] Table 2

[0044] As shown in Table 2, within the set range of exogenous auxin concentration, each treatment can promote the rooting of Citrus reticulata to varying degrees, showing a higher rooting rate and better root development compared to the control group. Among them, the 50 mg / L treatment is more outstanding in terms of overall rooting performance.

[0045] 2. Root induction by substrate Different substrates (ordinary hydroponics (Comparative Example 2), perlite (Example 1), coconut coir (Comparative Example 3), and river sand (Comparative Example 4)) were used to induce root growth in *Cinnamomum camphora*. The results are shown in Table 3.

[0046] Table 3

[0047] Table 3 shows that different root induction methods have a significant impact on the rooting and subsequent shoot growth of Citrus reticulata. Among them, plants treated with perlite showed better overall performance in terms of rooting initiation time, number of roots, and average root length. Furthermore, the rooting rate at 60 days and the sprouting of new shoots were superior to those treated with river sand and coconut coir. In contrast, the number of roots, root growth, and shoot sprouting ability were lower in the river sand and coconut coir treatments.

[0048] 3. Use of nutrient solution Nutrient solutions were supplied in a nutrient solution gradient manner (Example 1) and a full-concentration nutrient solution (100% volume concentration) manner (Comparative Example 1) to cultivate the cinnamon orange. The results are shown in Table 4.

[0049] Table 4

[0050] As shown in Table 4, the treatment group using a nutrient solution gradient supply method (stepped nutrient solution group) exhibited better adaptability during the hydroponic acclimatization and growth of the tangerine. Compared with the control group directly supplied with full-concentration nutrient solution (100% volume concentration), the plants treated with the stepped nutrient solution showed higher survival rates, lower root rot rates, and a significant increase in the number of new roots. This indicates that the nutrient solution gradient supply method is beneficial for the smooth transition of the tangerine from the water stage to the nutrient solution culture stage.

[0051] In addition, from Figure 1 It can be seen that in the stepwise nutrient solution group, the root tips remained milky white or pale yellow for 3-5 days after being transferred to hydroponics, gradually extending towards the water; after 10-15 days, the number of new roots increased significantly, the root epidermis was intact and tender, and some showed prominent primary lateral roots; after 30-40 days, most individuals formed well-structured and abundant aquatic roots, with obvious secondary lateral roots. The group using the full-concentration nutrient solution (…) Figure 2 After 3-5 days of hydroponics, the root tips rapidly lose water, and some develop translucent, water-soaked necrosis. The root color gradually changes from milky white to light brown. After 10-15 days of hydroponics, a large number of new roots turn brown, rot, and fall off. The roots become slimy and have an unpleasant odor. After 30-40 days of hydroponics, the individuals that can maintain growth have few new roots and few lateral roots. Direct full-concentration nutrient solution causes significant root hypoxia due to osmotic stress, leading to secondary rot and failure of root adaptation.

[0052] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0053] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for inducing root growth in hydroponically using *Cinnamomum camphora*, characterized in that, Includes the following steps: Plant pretreatment; Hormone-induced root treatment: The treated roots of the Citrus cinnabarii were soaked in an exogenous auxin solution; Perlite substrate root induction transition: The cinnabar orange was planted in a transition substrate, which included perlite, to obtain the planted plants; Fogging and humidity-controlled root-inducing environment: The planted plants are placed in a fogging or humidity-controlled environment to induce root growth, resulting in root-inducing plants; the relative humidity of the fogging or humidity-controlled environment is 75-85%, and the temperature is 20-30℃. Hydroponics: The root-inducing plantlets are transferred to a hydroponic planting device for hydroponics; the hydroponics includes: hydroponics in clean water until secondary lateral roots of a predetermined length are formed, followed by nutrient solution culture.

2. The hydroponic root-inducing method for Citrus reticulata according to claim 1, characterized in that, The plant pretreatment includes the following steps: selecting healthy tangerine trees, rinsing them, soaking them in a disinfectant, and air-drying them.

3. The hydroponic root-inducing method for Citrus reticulata according to claim 1, characterized in that, The exogenous auxin includes indolebutyric acid, and the concentration of the exogenous auxin solution is 40~60 mg / L; In the aforementioned mist-controlled root-inducing environment step, the perlite root-inducing period is 50-90 days.

4. The hydroponic root-inducing method for Citrus reticulata according to claim 1, characterized in that, In the nutrient solution culture step, the nutrient solution is supplied using an incremental gradient method, as follows: Days 1-15: 20% volume concentration nutrient solution; Days 16-30: 40% volume concentration nutrient solution; Days 31-45: 60% volume concentration nutrient solution; Days 46-60: 80% volume concentration nutrient solution; 61 days and beyond: 100% volume concentration of nutrient solution.

5. The hydroponic root-inducing method for Citrus reticulata according to claim 4, characterized in that, The nutrient solution includes solution A, solution B, and solution C; Solution A includes calcium nitrate tetrahydrate and potassium nitrate; the concentration of calcium nitrate tetrahydrate in the nutrient solution is 900~945 mg / L, and the concentration of potassium nitrate is 600~750 mg / L. Solution B comprises ammonium dihydrogen phosphate and magnesium sulfate heptahydrate; the concentration of ammonium dihydrogen phosphate in the nutrient solution is 100~140 mg / L, and the concentration of magnesium sulfate heptahydrate is 480~500 mg / L. Solution C comprises ferric disodium ethylenediaminetetraacetate, boric acid, manganese sulfate tetrahydrate, zinc sulfate heptahydrate, copper sulfate pentahydrate, and ammonium molybdate tetrahydrate. In the nutrient solution, the concentration of ferric disodium ethylenediaminetetraacetate is 30-40 mg / L, the concentration of boric acid is 2.8-2.9 mg / L, the concentration of manganese sulfate tetrahydrate is 2.1-2.2 mg / L, the concentration of zinc sulfate heptahydrate is 0.2-0.3 mg / L, the concentration of copper sulfate pentahydrate is 0.07-0.09 mg / L, and the concentration of ammonium molybdate tetrahydrate is 0.01-0.03 mg / L.

6. The hydroponic root-inducing method for Citrus reticulata according to claim 1, characterized in that, The hydroponics process includes changing the water every 3-5 days, and then culturing the aquatic roots in nutrient solution after they continue to grow and form secondary lateral roots with a length of ≥2mm. The pH of the nutrient solution is controlled at 6.0~6.

5.

7. The hydroponic root-inducing method for Citrus reticulata according to any one of claims 1-6, characterized in that, It also includes disease prevention, which includes: in the misting and humidification root-inducing environment step and in the hydroponic step, whole-plant sterilization treatment is carried out every 14 to 21 days.

8. The hydroponic root-inducing method for Citrus reticulata according to claim 1, characterized in that, In the perlite substrate root-inducing transition step, the planting includes the following steps: Fill the bottom of the permeable container with transition substrate, place the cinnabar orange in the center of the container, continue filling with transition substrate until it covers and fixes the root system, and water it.

9. The nutrient solution used in the hydroponic root-inducing method for Citrus reticulata as described in any one of claims 1-8.

10. The hydroponic root induction method for Citrus reticulata as described in claims 1-8 or the application of the nutrient solution as described in claim 9 in the hydroponic cultivation of Citrus plants.

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