Method for raising seedlings of Salix chuanensis by cutting in field

Abstract

The invention provides a method for raising seedlings of Salix chuanensis by cutting in a field, and relates to the field of vegetative propagation of plants. The method comprises the following steps: ploughing, smashing, disinfecting and flattening soil of a cutting bed to obtain a treated cutting bed; the method comprises the following steps: soaking a willow branch in water to obtain a water-soaked branch, and cutting the water-soaked branch to obtain a cutting strip section as a cutting slip; soaking the cutting slips in a mixed solution of naphthylacetic acid, indoleacetic acid and water, and dehydrating the surfaces of the cutting slips to obtain treated cutting slips; the treated cutting slips are cut into the treated cutting bed for seedling raising, and salix chuanensis seedlings are obtained; and transplanting the salix chuanensis seedlings to a nursery for seedling raising. According to the method, the survival rate of the salix chuanensis can be remarkably increased, the salix chuanensis grows rapidly, the seedling raising time is short, the cost is low, greenhouse covering, temperature and humidity control and the like are needed in seedling raising of most plants in winter, however, in the seedling raising process of the salix chuanensis, the germination rate and the survival rate which are equivalent to those after greenhouse erecting can be achieved without greenhouse erecting; the operation is simple, and large-scale propagation and application of the salix chuanensis are facilitated.

Description

Technical Field

[0001] This application relates to the field of plant asexual reproduction, and in particular to a method for field propagation of Salix trifoliata by cuttings. Background Technology

[0002] *Salix trifoliata*, belonging to the genus *Salix* of the family Salicaceae, is a shrub or small tree, 3-5 m tall. It is a native wetland tree species of Dongting Lake and an important energy shrub, characterized by its rapid growth and large above-ground biomass. It has strong resistance to flooding and can accumulate heavy metals such as cadmium. With its well-developed root system, *Salix trifoliata* plays a role in windbreak and dike reinforcement, wave dissipation and shoreline protection, and water purification. It is an ideal native plant for the ecological restoration of the Dongting Lake wetland.

[0003] Due to the destruction of the ecological environment of the Dongting Lake wetland in recent years, the ecological niche of *Salix trifoliata* has been encroached upon by reeds and poplars, leading to community degradation. Its population size and distribution area in the Dongting Lake area have decreased sharply, and the community distribution is fragmented, showing a serious trend of degradation. Therefore, the cultivation and propagation of *Salix trifoliata* is particularly important. However, the seeds of *Salix trifoliata* are extremely small and have a short lifespan, resulting in a very low seed germination rate.

[0004] Therefore, this application mentions a method for propagating Salix trifoliata that has solved the above problems. Summary of the Invention

[0005] The purpose of this application is to provide a method for field propagation of Salix trifoliata by cuttings to solve the above-mentioned problems.

[0006] To achieve the above objectives, this application provides a method for field propagation of Salix trifoliata by cuttings, comprising: The soil in the planting bed is tilled, broken up, disinfected, and leveled before being planted. Soak the branches of the Sichuan Three-Staple Willow in water to obtain soaked branches, and cut the soaked branches into cuttings as cuttings. The cuttings are soaked in a mixed solution of naphthaleneacetic acid, indoleacetic acid and water, and the surface is dehydrated to obtain the treated cuttings; The treated cuttings are inserted into the treated cutting bed for seedling cultivation to obtain *Salix trifoliata* seedlings; the *Salix trifoliata* seedlings are then transplanted to the nursery.

[0007] Optionally, the method for field propagation of Salix trifoliata by cuttings described herein satisfies at least one of the following conditions: (1) The water immersion is carried out in mid-December to January, and the temperature of the water immersion is 3-10°C; (2) The cuttings are taken in January; (3) The transplanting was carried out in April.

[0008] Optionally, the method for field propagation of Salix trifoliata by cuttings described herein satisfies at least one of the following conditions: (1) Disinfection was performed using carbendazim solution; (2) In the mixture used for the soaking, the mass concentration of the naphthaleneacetic acid is 1-5%; (3) In the mixture used for soaking, the mass concentration of indoleacetic acid is 1-5%.

[0009] Optionally, the pH of the planting bed is 5-6, and the soil is tilled to a depth of 20-25 cm.

[0010] Optionally, the height of the processed insertion bed is 15-20 cm and the width is 100-120 cm.

[0011] Optionally, the method for field propagation of Salix trifoliata by cuttings described herein satisfies at least one of the following conditions: (1) The immersion time is 5-7 days; (2) The soaking time is 12-24 h.

[0012] Optionally, the cutting has 3-4 lateral buds, is 10-12 cm long, and the cutting is 0.6-1.2 cm from the node.

[0013] Optionally, the cutting depth is 4-5 cm, and at least 2 buds are retained on the upper part of the treated cutting, with a plant spacing of 8-10 cm and a row spacing of 10-14 cm.

[0014] Optionally, the method for field propagation of Salix trifoliata by cuttings described herein satisfies at least one of the following conditions: (1) The height of the seedlings of the Sichuan Three-Stamen Willow is 25-35 cm; (2) During the seedling period, in mid-March, the seedlings of the Sichuan Three-Stamen Willow were pruned to remove lateral buds and suckers; (3) The specifications for digging holes in the nursery after transplanting are 15-20 cm long, 15-20 cm wide, and 15-20 cm high, with a plant spacing of 40-60 cm and a row spacing of 50-80 cm.

[0015] Optionally, no shed construction is required during the seedling cultivation process.

[0016] Compared with the prior art, the beneficial effects of this application include: The field cutting propagation method for *Salix trifoliata* provided in this application can significantly improve the survival rate of *Salix trifoliata*, promote rapid growth, and shorten the seedling time. Furthermore, it is low-cost. While most plants require greenhouses to control temperature and humidity during winter seedling cultivation, this method achieves comparable germination and survival rates to those achieved with greenhouses, without the need for such structures. The method is simple to operate and facilitates large-scale propagation and application of *Salix trifoliata*. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0018] Figure 1 This is a photograph of the seedling stage in the field cutting propagation method of Salix trifoliata provided in Example 1. Detailed Implementation

[0019] First, the solution provided in this application will be explained in more detail as follows: This application provides a method for field propagation of Salix trifoliata by cuttings, including: The soil in the planting bed is tilled, broken up, disinfected, and leveled before being planted. It should be noted that the Sichuan three-spotted willow is a wetland plant with a well-developed root system. It is suitable for growing in environments such as waterside, wetlands, and marshes. The seedbed should be a flat field with loose soil, good drainage and irrigation, and close to a water source. Sandy loam is the best soil type. Soak the branches of the Sichuan Three-Staple Willow in water to obtain soaked branches, and cut the soaked branches into cuttings as cuttings. It is important to note that healthy, disease-free, and semi-lignified current-year branches of *Salix trifoliata* should be selected. These branches exhibit vigorous cell division, easily inducing callus and adventitious root formation. In contrast, nutrients in older branches have already been transferred to the trunk or new growth areas, making rooting difficult. Since the cut branches experience a break in water supply due to separation from the tree, soaking allows them to fully absorb water, restoring cell turgor pressure and preventing dehydration and death before planting. Furthermore, since the planting takes place in winter, the branches are dormant; a watery environment stimulates dormant buds to regain physiological activity, preparing them for rooting. Finally, soaking softens the bark, promoting callus formation, and ultimately, the primary goal is to promote rooting and subsequent survival of the cuttings. In some embodiments, when cutting cutting segments, the base cut is made at an angle along the node to increase the water absorption area, and the top is cut flat to reduce water evaporation; The cuttings are soaked in a mixed solution of naphthaleneacetic acid, indoleacetic acid and water, and the surface is dehydrated to obtain the treated cuttings; It should be noted that naphthaleneacetic acid (NAA) is a synthetic auxin that can promote cell division and induce the formation of callus and adventitious roots, while indoleacetic acid (IAA) is a natural auxin that participates in cell elongation and differentiation, but is easily oxidized and decomposed. Using it in combination with NAA can prolong its duration of action and make up for the shortcomings of a single hormone. The treated cuttings are inserted into the treated cutting bed for seedling cultivation to obtain *Salix trifoliata* seedlings; the *Salix trifoliata* seedlings are then transplanted to the nursery.

[0020] In some embodiments, cuttings are best taken on cloudy days or sunny afternoons to reduce water evaporation from the cuttings. After taking cuttings, water them intermittently to keep the soil moist but avoid waterlogging. About 20 days after taking cuttings, the leaf buds of the *Salix trifoliata* cuttings will begin to sprout. If there is an early spring cold snap, sprouting will be delayed. Cover the cutting bed with mulch but avoid watering. By mid-March, remove the buds of the *Salix trifoliata* cuttings by hand, removing lateral buds and excess suckers to reduce low branches, lower the risk of pests and diseases, and make the trunk straight.

[0021] In addition, water should be controlled appropriately 1-2 days before transplanting to avoid loosening of the soil around the roots. At this time, the root system is more robust and the survival rate is higher. After transplanting, water thoroughly.

[0022] In some embodiments, the method for field propagation of Salix trifoliata by cuttings meets at least one of the following conditions: (1) The water immersion is carried out in mid-December to January, and the temperature of the water immersion is 3-10°C; Optionally, the water immersion can be carried out at any time between mid-December, late December, early January, mid-January, late January, or December and January, and the water immersion temperature can be any value between 3℃, 4℃, 5℃, 6℃, 7℃, 8℃, 9℃, 10℃, or 3-10℃. Preferably, the water immersion is carried out in the first half of January; It is important to note that cuttings should not be taken after January. During December, the branches are still in deep dormancy, and taking cuttings at this time will result in slow rooting. After February, as the temperature rises, the leaf buds gradually sprout and consume nutrients, resulting in insufficient energy for root development. "Leaves first, roots later" is likely to lead to cutting failure. Therefore, January is the end of the branches' dormancy period, with sufficient and unused nutrients, which is conducive to rooting. (2) The cuttings are taken in January; Optionally, the cuttings can be taken in early January, mid-January, late January, or any time in January. (3) The transplanting was carried out in April.

[0023] Optionally, the transplanting time can be any time in early April, mid-April, late April, or any period in April.

[0024] It is important to note that transplanting is best done on cloudy days. If transplanting is done on a sunny day, it should be done in the early morning or late evening.

[0025] In some embodiments, the method for field propagation of Salix trifoliata by cuttings meets at least one of the following conditions: (1) Disinfection was performed using carbendazim solution; It is important to note that using carbendazim solution for disinfection can kill soil pathogens, reduce the risk of infection in cuttings, and improve the survival rate of cuttings. (2) In the mixture used for the soaking, the mass concentration of the naphthaleneacetic acid is 1-5%; Optionally, the mass concentration of naphthaleneacetic acid in the soaking mixture can be any value between 1%, 2%, 3%, 4%, 5%, or 1-5%. (3) In the mixture used for soaking, the mass concentration of indoleacetic acid is 1-5%.

[0026] Optionally, the mass concentration of indoleacetic acid in the soaking mixture can be any value between 1%, 2%, 3%, 4%, 5%, or 1-5%.

[0027] In some embodiments, the pH of the planting bed is 5-6, and the soil is tilled to a depth of 20-25 cm.

[0028] Optionally, the pH of the planting bed can be any value between 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, or 5-6, and the soil tillage depth can be any value between 20 cm, 21 cm, 22 cm, 23 cm, 24 cm, 25 cm, or 20-25 cm.

[0029] In some embodiments, the height of the processed insertion bed is 15-20 cm and the width is 100-120 cm.

[0030] Optionally, the height of the processed insertion bed can be any value between 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm or 15-20 cm, and the width can be any value between 100 cm, 110 cm, 120 cm or 100-120 cm.

[0031] In some embodiments, the method for field propagation of Salix trifoliata by cuttings meets at least one of the following conditions: (1) The immersion time is 5-7 days; Optionally, the immersion time can be any value between 5 days, 6 days, 7 days, or 5-7 days; (2) The soaking time is 12-24 h.

[0032] Optionally, the soaking time can be any value between 12 h, 16 h, 20 h, 24 h, or 12-24 h.

[0033] In some embodiments, the cutting has 3-4 lateral buds, is 10-12 cm long, and the cutting is 0.6-1.2 cm from the node.

[0034] Optionally, the cuttings can have 3 or 4 lateral buds, and the length can be any value between 10 cm, 11 cm, 12 cm or 10-12 cm. The distance between the cutting cut and the node can be any value between 0.6 cm, 0.8 cm, 1 cm, 1.2 cm or 0.6-1.2 cm. In some embodiments, the cutting depth is 4-5 cm, and at least 2 buds are retained on the upper part of the treated cutting, with a plant spacing of 8-10 cm and a row spacing of 10-14 cm.

[0035] Optionally, the depth of cutting can be any value between 4 cm, 4.5 cm, 5 cm or 4-5 cm, the number of buds on the upper part of the treated cutting can be any value between 2, 3, 4 or more, the plant spacing can be any value between 8 cm, 9 cm, 10 cm or 8-10 cm, and the row spacing can be any value between 10 cm, 11 cm, 12 cm, 13 cm, 14 cm or 10-14 cm.

[0036] In some embodiments, the method for field propagation of Salix trifoliata by cuttings meets at least one of the following conditions: (1) The height of the seedlings of the Sichuan Three-Stamen Willow is 25-35 cm; Optionally, the height of the seedlings of Salix trifoliata can be any value between 25 cm, 30 cm, 35 cm or 25-35 cm; (2) During the seedling period, in mid-March, the seedlings of the Sichuan Three-Stamen Willow were pruned to remove lateral buds and suckers; (3) The specifications for digging holes in the nursery after transplanting are 15-20 cm long, 15-20 cm wide, and 15-20 cm high, with a plant spacing of 40-60 cm and a row spacing of 50-80 cm.

[0037] The spacing between plants in the nursery after transplanting can be any value between 40 cm, 45 cm, 50 cm, 55 cm, 60 cm or 40-60 cm, and the row spacing can be any value between 50 cm, 60 cm, 70 cm, 80 cm or 50-80 cm.

[0038] In some embodiments, the dimensions of the holes dug in the nursery are 15-20 cm in length, 15-20 cm in width, and 15-20 cm in height.

[0039] Optionally, the length of the hole in the nursery can be any value between 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm or 15-20 cm, the width of the hole can be any value between 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm or 15-20 cm, and the height of the hole can be any value between 15 cm, 16 cm, 17 cm, 18 cm, 19 cm, 20 cm or 15-20 cm.

[0040] In some embodiments, no shed construction is required during the seedling cultivation process.

[0041] It should be noted that this application compares two treatments: one with an arched shed and the other without. Cuttings under the arched shed begin to sprout leaf buds at least 8 days earlier than those in the open air. However, the treatment does not have a significant impact on the germination rate and survival rate. Based on this, the field cutting propagation method of Salix trifoliata provided in this application can achieve the goal of not requiring an arched shed.

[0042] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0043] Example 1 This embodiment provides a method for field propagation of Salix trifoliata seedlings by cuttings. The specific process is as follows: S1: Select a flat field with loose soil, good drainage and irrigation, and close to a water source as the seedling bed (planting bed). The soil should be sandy loam with a pH of 5.13. Plow the soil to a depth of 20 cm. The planting bed should be 20 cm high and 100 cm wide. Two days before planting, spray the planting bed with a 500-fold dilution of carbendazim solution on a cloudy day to disinfect it. S2: At the end of December, take healthy, disease-free, and semi-lignified current-year branches of the Sichuan Three-Stamen Willow and soak them in a water pool for 7 days at a water temperature of 3-10℃. After soaking, cut the branches into cuttings as cuttings. Cut the cuttings into 10-12 cm long cuttings, retaining 3-4 buds. Make the cutting cut 1 cm away from the node and cut the base at an angle along the node. S3: Soak the cuttings in a mixed solution of naphthaleneacetic acid (NAA), indoleacetic acid (IAA), and water for 24 hours. Drain the water and insert the cuttings into the treated nursery on a cloudy day. The insertion depth should be about 4 cm, and at least 2 buds should be retained at the top of the cutting. The planting density should be 8-10 cm between plants and 10-14 cm between rows. After the cuttings are inserted, water them thoroughly to ensure that the cuttings are in close contact with the soil. S4: Water irregularly after cutting to keep the soil moist and avoid waterlogging. About 20 days after cutting, the leaf buds of the Sichuan Three-Syllable Willow cuttings will begin to sprout. In mid-March, remove the buds of the Sichuan Three-Syllable Willow cuttings by hand to reduce low branches, reduce the risk of pests and diseases, and make the trunk straight. S5: Select a flat site with loose soil and close to a water source as the nursery site. Clear away weeds, turn over the soil, level the soil, and dig holes with dimensions of 15 cm in length, 15 cm in width, and 15 cm in height. The plant spacing is 50 cm and the row spacing is 80 cm. S6: Around April, transplanting should be done on cloudy days. Transplant the seedlings when they reach about 30 cm in height, keeping them with soil. Control watering appropriately two days before transplanting, and water thoroughly after transplanting.

[0044] Actual specimens during the seedling stage, such as Figure 1 As shown, the photo was taken on January 11.

[0045] Example 2 The difference from Example 1 is that the mass concentration of naphthaleneacetic acid is 5% and the mass concentration of indoleacetic acid is 5%.

[0046] Example 3 The difference from Example 1 is that the mass concentration of naphthaleneacetic acid is 1% and the mass concentration of indoleacetic acid is 1%.

[0047] Comparative Example 1 In step S3, no naphthaleneacetic acid or indoleacetic acid is added; only water is used.

[0048] Comparative Example 2 In step S3, naphthaleneacetic acid is not added.

[0049] Comparative Example 3 In step S3, indoleacetic acid is not added.

[0050] Comparative Example 4 In step S2, immersion is carried out in February.

[0051] Comparative Example 5 The difference from Example 1 is that a shed was erected during the seedling cultivation process.

[0052] The germination rate and survival rate of the field cutting propagation methods of *Salix trifoliata* provided in the above embodiments and comparative examples were statistically analyzed. The germination rate of the cuttings was statistically analyzed 30 days after cutting, and the germination rate (%) was calculated as (number of germinating cuttings / total number of cuttings) × 100%. The survival rate of the cuttings was statistically analyzed 60 days after cutting, and the survival rate (%) was calculated as (number of surviving cuttings / total number of cuttings) × 100%. The specific statistical results are shown in Table 1.

[0053] Table 1. Germination rate and survival rate statistics

[0054] analyze: The above tests show that, based on the data from Examples 2 and 3, there is an optimal concentration of auxin. Higher concentrations may inhibit cell differentiation, while lower concentrations may fail to stimulate cell differentiation, thus affecting rooting. The germination and survival rates of Comparative Examples 1 and 2 indicate that the effect of using a single hormone is less than that of the mixed use in Example 1. The only variable in Comparative Example 4 compared to Example 1 is the soaking time; soaking in January effectively breaks the dormancy of *Salix babylonica*. The shed provides important insulation for the cuttings, promoting earlier germination, but the seedling cost is higher than in Example 1. The mixed use of 2.5% naphthaleneacetic acid and 2.5% indoleacetic acid significantly promotes the survival rate of *Salix babylonica* cuttings, with better results than single hormone treatment or no hormone treatment. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0055] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, any of the claimed embodiments can be used in any combination. The information disclosed in this background section is intended only to enhance the understanding of the general background of this application and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

Claims

1. A method for field propagation of Salix trifoliata by cuttings, characterized in that, include: The soil in the planting bed is tilled, broken up, disinfected, and leveled before being planted. Soak the branches of the Sichuan Three-Staple Willow in water to obtain soaked branches, and cut the soaked branches into cuttings as cuttings. The cuttings are soaked in a mixed solution of naphthaleneacetic acid, indoleacetic acid and water, and the surface is dehydrated to obtain the treated cuttings; The treated cuttings are inserted into the treated cutting bed for seedling cultivation to obtain seedlings of *Salix trifoliata*; the seedlings of *Salix trifoliata* are then transplanted into the nursery.

2. The method for field propagation of *Salix trifoliata* by cuttings according to claim 1, characterized in that, At least one of the following conditions must be met: (1) The water immersion is carried out in mid-December to January, and the temperature of the water immersion is 3-10°C; (2) The cuttings are taken in January; (3) The transplanting was carried out in April.

3. The method for field propagation of *Salix trifoliata* by cuttings according to claim 1, characterized in that, At least one of the following conditions must be met: (1) Disinfection was performed using carbendazim solution; (2) In the mixture used for the soaking, the mass concentration of the naphthaleneacetic acid is 1-5%; (3) In the mixture used for soaking, the mass concentration of indoleacetic acid is 1-5%.

4. The method for field propagation of *Salix trifoliata* by cuttings according to claim 1, characterized in that, The pH of the planting bed is 5-6, and the soil is tilled to a depth of 20-25 cm.

5. The method for field propagation of *Salix trifoliata* by cuttings according to claim 1, characterized in that, The height of the treated insertion bed is 15-20 cm and the width is 100-120 cm.

6. The method for field propagation of *Salix trifoliata* by cuttings according to claim 1, characterized in that, At least one of the following conditions must be met: (1) The immersion time is 5-7 days; (2) The soaking time is 12-24 h.

7. The method for field propagation of *Salix trifoliata* by cuttings according to claim 1, characterized in that, The cuttings have 3-4 lateral buds, are 10-12 cm long, and the cutting is 0.6-1.2 cm from the node.

8. The method for field propagation of *Salix trifoliata* by cuttings according to claim 1, characterized in that, The cuttings are inserted to a depth of 4-5 cm, and at least two buds are retained on the upper part of the treated cuttings. The plant spacing is 8-10 cm and the row spacing is 10-14 cm.

9. The method for field propagation of *Salix trifoliata* by cuttings according to claim 1, characterized in that, At least one of the following conditions must be met: (1) The height of the seedlings of the Sichuan Three-Stamen Willow is 25-35 cm; (2) During the seedling period, in mid-March, the seedlings of the Sichuan Three-Stamen Willow were pruned to remove lateral buds and suckers; (3) The specifications for digging holes in the nursery after transplanting are 15-20 cm long, 15-20 cm wide, and 15-20 cm high, with a plant spacing of 40-60 cm and a row spacing of 50-80 cm.

10. The method for field propagation of Salix trifoliata by cuttings according to any one of claims 1-9, characterized in that, No shed construction is required during the seedling cultivation process.

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