A kind of cutting propagation method of Robinia pseudoacacia

Abstract

The invention discloses a cutting propagation method of Robinia pseudoacacia, and belongs to the technical field of seedling propagation. The cutting propagation method comprises the following steps: (1) substrate and cutting bed processing; (2) cutting selection and processing: using Robinia pseudoacacia pinnate leaves as cuttings, and inserting them as soon as they are picked; (3) cutting; (4) post-cutting management. The invention uses Robinia pseudoacacia pinnate leaves as cutting materials, breaking through the selection range of Robinia pseudoacacia cutting propagation materials in the past, ensuring the stable retention of excellent traits of the propagation offspring materials, especially when the mother plant has branch mutations and the material is less, it can achieve rapid and efficient propagation of Robinia pseudoacacia.

Description

Technical Field

[0001] The invention belongs to the technical field of seedling propagation, and in particular relates to a cutting propagation method for Robinia pseudoacacia. Background Art

[0002] Robinia pseudoacacia is a deciduous tree with thick, dark bark and many cracks. The flowers are white, fragrant, and spike-shaped. The fruit is a pod, and each pod contains 4 to 10 seeds. Robinia pseudoacacia likes light and warm and humid climates. It is not strict about soil and has strong adaptability. It prefers deep, fertile, loose, and moist silt and sandy loam. Robinia pseudoacacia is native to North America. It was introduced to Europe in the early 17th century and to China in the late 19th century. At present, it has spread throughout North China, Northwest China, and the southern part of Northeast China. It is widely cultivated in 24 provinces and cities in my country. It is an irreplaceable tree species for soil and water conservation, timber, and feed. It plays an important role in producing wood, improving soil, and maintaining ecological balance.

[0003] For a long time, the asexual reproduction of Robinia pseudoacacia mainly adopts grafting and root burial, and rarely adopts tissue culture rapid propagation and cutting propagation. Grafting requires cultivating Robinia pseudoacacia over two years old as rootstock, and then grafting good quality Robinia pseudoacacia as scion onto the rootstock, so it requires a long seedling cultivation period, which increases the cost of seedling cultivation; root burial propagation is labor-intensive and time-consuming to dig roots, and the reproduction coefficient is low, which cannot meet production needs; although the tissue culture rapid propagation method has a fast reproduction speed, the experimental equipment is expensive and the operation technology requirements are high, so it is not easy to be used on a large scale in production. Therefore, Robinia pseudoacacia is most commonly propagated by cutting.

[0004] Robinia pseudoacacia is a tree species that is generally recognized as difficult to root. Therefore, there are not many reports on Robinia pseudoacacia cuttings, and most of them are done by using tender branches or hard branches. For example, patent application document 201310158783.1 discloses a method for propagating Robinia pseudoacacia by tender branch cuttings, which includes the following steps: (1) selecting a suitable time for cuttings; (2) preparing a cutting medium; (3) preparing a rooting agent; (4) treating cuttings and cuttings; (5) post-cutting management and transplanting. The cuttings selected for the method for propagating Robinia pseudoacacia by tender branch cuttings are as follows: selecting robust, disease-free and insect-free branches of Robinia pseudoacacia of the current year, cutting branches with a length of 8 to 12 cm and a diameter of 0.3 to 0.8 cm as cuttings, cutting the upper and lower cuts of the cuttings flat, with the upper cut 1.0 to 1.5 cm away from the cut bud, and the cut is smooth, and each cutting retains 2 to 4 leaflets in a compound leaf, and removes the remaining leaves. For example, patent application document 201510148615.3 discloses a method for rooting hardwood cuttings of Robinia pseudoacacia, which includes selecting one-year-old branches of Robinia pseudoacacia as cuttings, pruning the branches to an average length of 10 to 12 cm, quickly dipping the cut branches in alcohol, and then soaking them in ABT No. 1 rooting powder solution for 48 hours, and then inserting them into the sandy soil matrix of the seedbed. After the cuttings are completed, water them thoroughly and enter the seedling management stage.

[0005] It can be seen that the research on Robinia pseudoacacia cuttings in the prior art is mostly focused on branch cuttings. After all, branches can make it easier for cuttings to take root. By disinfecting and treating the cuttings with auxins, and fertilizing, weeding, and pest control in a timely manner, the survival rate of Robinia pseudoacacia cutting propagation can be improved. However, the number of Robinia pseudoacacia varieties is limited, and large-scale cuttings will also cause great damage to the existing Robinia pseudoacacia, seriously affecting the breeding process, and far from meeting market demand. Therefore, it is necessary to explore the selection of other cutting materials for Robinia pseudoacacia cutting propagation, which is used to solve the difficulty of insufficient Robinia pseudoacacia breeding materials, and at the same time can also reduce the damage caused to the existing Robinia pseudoacacia. Summary of the invention

[0006] The present invention is based on the inventor's discovery and understanding of the following facts and problems: Robinia pseudoacacia cutting propagation generally adopts the method of softwood and hardwood cutting propagation, but the number of Robinia pseudoacacia improved varieties is limited, and the coefficient of softwood and hardwood cutting propagation is low. Large-scale cuttings will also cause great damage to the existing Robinia pseudoacacia, while the number of Robinia pseudoacacia pinnate leaves is much larger than the number of branches. If the cutting can be successful, the selection range of Robinia pseudoacacia cutting materials can be widened, and the number of cutting materials can be greatly increased. However, there is no literature report on the use of Robinia pseudoacacia pinnate leaves as materials for cutting propagation. Therefore, it is necessary to study the method of Robinia pseudoacacia pinnate leaves cutting propagation to explore its possibility as cutting material.

[0007] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the present invention proposes a method for cutting propagation of pinnate leaves. The method uses the pinnate leaves of Robinia pseudoacacia as cutting materials, cooperates with appropriate cutting selection and processing methods, and post-cutting management methods, successfully realizes the cutting propagation of Robinia pseudoacacia pinnate leaves, breaks through the previous selection range of Robinia pseudoacacia cutting propagation materials, not only ensures the stable retention of excellent traits of the offspring materials, but also the reproduction coefficient is 2 to 3 times that of softwood cuttings, especially when the mother plant has branch mutations and the material is less, it can achieve rapid and efficient propagation of Robinia pseudoacacia, and greatly reduce the damage to the Robinia pseudoacacia mother plant.

[0008] Specifically, the technical solution adopted by the present invention is as follows:

[0009] A cutting propagation method for Robinia pseudoacacia comprises the following steps:

[0010] (1) Substrate and cutting bed treatment: Sterilize and disinfect the substrate into a nutrient cup, and then place it on the sterilize and disinfect sand body of the cutting bed. One day before cutting, water the nutrient cup by immersion pot method, and then dry the nutrient cup in the shade for 10 to 15 hours.

[0011] (2) Cutting collection and processing: From May to mid-June each year, collect healthy, disease-free and insect-free pinnate compound leaves of Robinia pseudoacacia of the current year, and then cut them into 10-15 cm long cuttings, retaining 1 / 2-2 / 3 of the two pairs of leaflets near the tip of the leaf axis near the petiole, remove the other leaflets, and plant them as soon as they are collected;

[0012] (3) Cutting: Dip the treated base of the cutting into a rooting agent, dry it in the shade, and then insert it into the substrate;

[0013] (4) Management after cutting: natural light, keep the ambient temperature at 25-28°C; ① 1st to 30th day after cutting: maintain the relative humidity of the air at 80-85%, water the nutrient cup by immersion method every 2-4 days, during which at least one time of watering by immersion method is supplemented with fungicide, and at least one time of watering by immersion method is supplemented with rooting agent; ② 31st to 60th day after cutting: maintain the relative humidity of the air at 75-80%, and irrigate the nutrient cup every 5-7 days or until the river sand in the nutrient cup turns white. The nutrient cups are watered by the immersion pot method from time to time, and nutrients are added at least once during the immersion pot watering; ③ From the 61st day of cutting to before transplanting: the relative humidity of the ambient air is maintained at 50-60%, and the nutrient cups are watered by the immersion pot method every 8-10 days or when the river sand in the nutrient cups turns white. When there are 2-4 side branches on the branches, each side branch has 3-6 pinnate leaves, and the root system grows out of the nutrient cup, it can be moved from the cutting bed to the field for planting.

[0014] According to the above-mentioned method for propagation of Robinia pseudoacacia by cuttings, in step (1), the matrix includes a lower layer of nutrient soil and an upper layer of river sand; preferably, the nutrient soil is humus soil, and the river sand is fine river sand with a particle size of 1 to 1.5 mm; more preferably, the volume ratio of the nutrient soil to the river sand is 7:1 to 9:1; further preferably, the volume ratio of the nutrient soil to the river sand is 8:1.

[0015] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein, in step (1) and step (4), the specific operation of supplying water to the nutrient cup by the immersion pot method is: injecting water into the sand body of the cutting bed to raise the water level to 1 / 3 of the height of the nutrient cup, and draining the water after the substrate is infiltrated.

[0016] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein, in step (2), the cuttings are pinnate compound leaf cuttings with leaf axes having basal protrusions; preferably, the diameter of the cuttings is greater than or equal to 1.5 mm.

[0017] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein, in step (2), the removed leaflets retain the leaf petiole of at least 1 mm.

[0018] According to the above-mentioned Robinia pseudoacacia cutting propagation method, step (2) specifically includes the following steps: from May to mid-June each year, select healthy and pest-free Robinia pseudoacacia branches of the current year, pick the pinnate compound leaves from the base of the leaf axis, and then cut them into 10-15 cm cuttings from the base to the tip, and the cutting position is 0.4-0.6 cm above the upper end of the leaflet that needs to be retained on the leaf axis. After cutting, the cutting has 3-4 pairs of leaflets, and then cut off 1-2 pairs of leaflets near the base of the cutting, retaining 2 pairs of leaflets near the tip, and then cut off 1 / 3-1 / 2 of the retained leaflet near the tip, and retain 1 / 2-2 / 3 of the retained leaflet near the petiole.

[0019] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein, in step (3), 1 / 3 to 1 / 2 of the base of the cutting is dipped in the rooting agent for 3 to 5 seconds, dried in the shade and then inserted into the matrix, and the cutting depth is 1 / 3 to 1 / 2 of the length of the cutting; preferably, the rooting agent is a mixed aqueous solution of 1000 mg / kg of indolebutyric acid and naphthylacetic acid; more preferably, the mass ratio of the indolebutyric acid to the naphthylacetic acid is 2:1.

[0020] According to the above-mentioned Robinia pseudoacacia cutting propagation method, in step (3), before cutting, a hole is pierced on the substrate with a stick, the diameter of the stick is greater than or equal to the maximum width of the leaf axis of the cutting, and then the cutting is inserted into the substrate, and the cutting and the substrate around the hole are compacted.

[0021] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein step (4) specifically comprises the following steps:

[0022] ① On the 1st to 30th day of cutting: maintain the ambient temperature at 25 to 28° C., the relative air humidity at 80 to 85%, water the nutrient cups by immersion every 2 to 4 days, sterilize and disinfect the nutrient cups by immersion using 900 to 1100 times diluted 50% carbendazim wettable powder on the 10th to 14th day, then slowly rinse the sandy bed with water, replace the water immersion with 450 to 550 mg / kg indolebutyric acid aqueous solution on the 14th to 16th day, and replace the water immersion with 450 to 550 mg / kg naphthaleneacetic acid aqueous solution on the 23rd to 25th day of cutting;

[0023] ② Day 31 to 60 of cutting: maintain the ambient temperature at 25 to 28° C., the relative humidity at 75 to 80%, water the nutrient cups by immersion every 5 to 7 days or when the river sand in the nutrient cups turns white, replace the water immersion pot treatment with nutrient solution I on the 44th to 46th day, the nutrient solution I includes 18 to 22% urea, 10 to 14% potassium dihydrogen phosphate, 16 to 20% potassium chloride, and the balance is water, replace the water immersion pot treatment with nutrient solution II on the 54th to 56th day, the nutrient solution II includes 28 to 32% urea, 8 to 12% potassium dihydrogen phosphate, 13 to 17% potassium chloride, 2.5 to 3.5% magnesium sulfate, 0.4 to 0.6% zinc sulfate, and the balance is water;

[0024] ③ From the 61st day after cutting to before transplanting: maintain the ambient temperature at 25-28°C and the relative humidity at 50-60%, water the nutrient cups by immersion method every 8-10 days or when the river sand in the nutrient cups turns white, when the Robinia pseudoacacia seedlings have 2-4 side branches, each of which has 3-6 pinnate leaves, and the roots grow out of the nutrient cups, cut off the roots outside the cups, and then the seedlings can be transplanted from the cutting bed into the field for planting;

[0025] Preferably, the nutrient solution I comprises 20% urea, 12% potassium dihydrogen phosphate, 18% potassium chloride, and the balance is water, and the nutrient solution II comprises 30% urea, 10% potassium dihydrogen phosphate, 15% potassium chloride, 3% magnesium sulfate, 0.5% zinc sulfate, and the balance is water.

[0026] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein, in step (4), on the 1st to 30th day of cutting: on sunny days from 10:00 to 15:00 every day, use a 70% shade net at a height of 1.5 m to provide shade for 4 to 5 hours; on the 31st to 60th day of cutting: on sunny days from 11:00 to 15:00 every day, use a 70% shade net at a height of 1.5 m to provide shade for 2 to 4 hours.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention uses the pinnate compound leaves of Robinia pseudoacacia as cutting materials, breaking through the selection range of previous Robinia pseudoacacia cutting propagation materials, and the propagation materials are easy to obtain, providing a more convenient and efficient method for Robinia pseudoacacia asexual propagation;

[0029] (2) The present invention uses the pinnate compound leaves of Robinia pseudoacacia as cutting materials, and the bred seedlings can stably retain the characteristics of the mother plant, and the reproduction coefficient is 2 to 3 times that of softwood cuttings. Especially when the Robinia pseudoacacia mother plant has a branch mutation and there is less available material, Robinia pseudoacacia can be propagated quickly and efficiently, playing an important role in the cultivation of new Robinia pseudoacacia varieties;

[0030] (3) The present invention waters the nutrient cups by the immersion pot method one day before cutting and then dries them in the shade, which can provide more suitable soil moisture conditions for the newly cut cuttings compared to watering them immediately after cutting;

[0031] (4) The cuttings selected by the present invention have 1 / 3 to 1 / 2 of the leaves cut off, which reduces the respiration and transpiration of the leaves, effectively reduces the risk of leaf drying during the rooting process, and at the same time selects a distribution method to retain two pairs of the leaflets, so that the leaves consume the original nutrients of the cuttings more evenly before the cuttings survive. The two pairs of leaflets share the risk of leaf drying, increase the probability of cutting survival, and are conducive to timely photosynthesis after rooting. Therefore, this cutting processing method is conducive to the successful cutting of Robinia pseudoacacia pinnate compound leaves, and effectively improves the rooting rate and survival rate of cuttings;

[0032] (5) The present invention adopts the immersion basin method for watering before cutting and during the cutting management process, which can scientifically and reasonably adjust the humidity of the substrate. On the one hand, after drainage, the sand body of the cutting bed can still remain moist for a long time, continuously providing the cuttings with a suitable humidity environment, which is more breathable than the method of moisturizing by covering with a film, and is not easy to cause root rot; on the other hand, after the water is buffered by the sand body of the cutting bed and the nutrient cup, the water is absorbed by the substrate and can be drained in time to prevent waterlogging. It will not cause a large amount of local water to soak the roots of the cuttings for a long time like direct watering, nor will it wet and impact the cuttings like spraying water, reducing the damage to the delicate cuttings or seedlings, and more effectively protecting the cuttings or seedlings in the rooting process, while also avoiding the problems of uneven spraying, substrate loss, and compaction. The above two aspects work together to help achieve the cutting propagation of Robinia pseudoacacia pinnate compound leaves, and effectively improve the rooting rate, survival rate and seedling quality of cuttings;

[0033] (6) The present invention gradually reduces the relative humidity of the air and the frequency of water supply from the initial, middle and late stages during the cutting management process, which can adapt to the variable humidity requirements of Robinia pseudoacacia pinnate leaves before rooting and survival, and is conducive to improving the rooting rate of cuttings and the survival rate of outplanting;

[0034] (7) The present invention uses a pot-immersion method to apply fungicides, rooting agents, and nutrient solutions during the cutting management process, which effectively promotes the rooting of cuttings and the survival of seedlings;

[0035] (8) The Robinia pseudoacacia cutting propagation method of the present invention can achieve a rooting rate of more than 85.45% after cutting, and the Robinia pseudoacacia seedlings are of good quality, with strong roots, branches and leaves. The survival rate after rooting is more than 92.16%. In the same period of time, due to the abundance of pinnate compound leaf cutting materials, compared with using a smaller number of tender branches or hard branches for cuttings, several times more Robinia pseudoacacia seedlings can be obtained, and the propagation speed is fast, which is suitable for market application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A front view of a processed Robinia pseudoacacia pinnate leaf cutting is shown;

[0037] Figure 2 A side view of a processed Robinia pseudoacacia pinnate leaf cutting is shown;

[0038] Figure 3 The figure shows the rooting condition of the cuttings obtained on the 35th day after the cutting propagation method of Robinia pseudoacacia according to Example 1. DETAILED DESCRIPTION

[0039] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0040] A cutting propagation method for Robinia pseudoacacia comprises the following steps:

[0041] (1) Substrate and cutting bed treatment: Sterilize and disinfect the substrate into a nutrient cup, and then place it on the sterilize and disinfect sand body of the cutting bed. One day before cutting, water the nutrient cup by immersion pot method, and then dry the nutrient cup in the shade for 10 to 15 hours.

[0042] (2) Cutting collection and processing: From May to mid-June each year, collect healthy, disease-free and insect-free pinnate compound leaves of Robinia pseudoacacia of the current year, and then cut them into 10-15 cm long cuttings, retaining 1 / 2-2 / 3 of the two pairs of leaflets near the tip of the leaf axis near the petiole, remove the other leaflets, and plant them as soon as they are collected;

[0043] (3) Cutting: Dip the treated base of the cutting into a rooting agent, dry it in the shade, and then insert it into the substrate;

[0044] (4) Management after cutting: natural light, keep the ambient temperature at 25-28°C; ① 1st to 30th day after cutting: keep the relative humidity of the air at 80-85%, water the nutrient cup by immersion method every 2-4 days, during which at least one time of watering by immersion method is added with fungicide, and at least one time of watering by immersion method is added with rooting agent; ② 31st to 60th day after cutting: keep the relative humidity of the air at 75-80%, and add river sand in the nutrient cup every 5-7 days or When the water turns white, the nutrient cup is watered by the immersion pot method, and nutrients are added at least once during the immersion pot watering; ③ From the 61st day of cutting to before transplanting: the relative humidity of the ambient air is maintained at 50-60%, and the nutrient cup is watered by the immersion pot method every 8-10 days or when the river sand in the nutrient cup turns white. When there are 2-4 side branches on the branch, each side branch has 3-6 compound leaves, and the root system grows out of the nutrient cup, it can be moved from the cutting bed to the field for planting.

[0045] Working principle: The present invention creatively uses Robinia pseudoacacia pinnate leaves as cutting materials, breaking through the selection range of Robinia pseudoacacia cutting propagation materials in the past, ensuring the stable retention of excellent traits of the propagation offspring materials, especially when the mother plant has branch mutations and the material is less, it can achieve rapid and efficient propagation. At the same time, the present invention selects a specific cutting processing method, a immersion basin water supply method, and a humidity gradient control method, effectively realizing the cutting propagation of Robinia pseudoacacia pinnate leaves, and the cutting rooting rate, survival rate after rooting, and seedling quality are all high.

[0046] Although there are also methods for leaf cuttings of other tree species in the relevant technology, for example, patent application document 201711222662.3 discloses a method for leaf cuttings of Podocarpus caryophyllus, but its abstract also shows that the leaves of Podocarpus caryophyllus have strong germination ability. However, Robinia pseudoacacia is a recognized tree species that is difficult to root, and there is currently no research on the use of its pinnate leaves for cuttings and propagation. Therefore, those skilled in the art should understand that the reproductive characteristics between Robinia pseudoacacia and other tree species are quite different, and the methods for leaf cuttings and propagation of other tree species cannot be transferred to the present invention.

[0047] Those skilled in the art should understand that the cuttings cannot provide nutrition to the branches and leaves in time during the rooting process. The above technical solution is adopted, and the distribution method is selected to retain 2 pairs of leaflets, so that the consumption of the original nutrients of the cuttings by the leaves before the cuttings survive is more balanced, and at the same time, photosynthesis is carried out to supplement nutrients, share and reduce the risk of leaf dryness, which can play an insurance role; the cuttings are cut off 1 / 3 to 1 / 2 of the retained leaves, reducing the respiration and transpiration of the leaves, and ultimately improving the survival rate of the cuttings. The cuttings used for cuttings are basically 10 to 15 cm. If more than 3 pairs of leaflets are retained, it will not only increase unnecessary nutrient consumption, but also reduce the cutting depth; if only 1 pair of complete leaflets is retained, it will cause concentrated consumption of the original nutrients, and the leaves will be more likely to dry up, which will lead to the failure of the entire cutting after drying up.

[0048] Watering or spraying water is commonly used in the process of Robinia pseudoacacia hard branch or soft branch cutting. The present invention uses pinnate leaves for cutting, which is different from general hard branch or soft branch cutting. Since the rachis of the pinnate leaves is relatively thin and weak relative to the branches, if watering is directly applied after cutting, it is easy to cause the matrix to be lost, the cuttings to fall over, or the watering is not thorough and uneven, causing some cuttings to rot or some cuttings to dry up, or it is easy to cause the matrix to harden after watering, and the cuttings to dry up because of the poor air permeability of the matrix. If the method of spraying water is adopted, the cuttings will be wetted and impacted, or the watering is not thorough, and the matrix cannot reach the humidity required for the rooting of the pinnate leaves, making the cuttings difficult to take root and survive. Moreover, spraying water is usually combined with the method of coating the matrix to ensure that the matrix humidity can be maintained in a good humidity range for a long time, but the coating is easy to cause poor air permeability, and the growth of pathogens causes the root rot of the Robinia pseudoacacia pinnate leaf cuttings. Therefore, in order to improve the rooting and survival probability of the Robinia pseudoacacia pinnate compound leaf cuttings and the quality of the propagated seedlings, the present invention adopts the immersion basin method to supply water before cutting and during the cutting management process, which can scientifically and reasonably adjust the humidity of the substrate, the surface layer will not be hardened, and after drainage, the sand body of the cutting bed can still remain moist for a long time, continuously providing the cuttings with humidity and a breathable environment suitable for rooting.

[0049] In addition, the nutrient cup is soaked in the pot and then aired in the shade one day before cutting, which can provide good soil moisture for cutting, and neither too much water will cause root rot nor too dryness will cause the newly cut cuttings to dry out due to lack of water. It is understandable that the pot does not need to be soaked on the day of cutting, and the pot is soaked on the 2nd to 4th day of cutting.

[0050] For Robinia pseudoacacia hardwood or softwood cuttings, fixed air humidity and watering frequency are usually used in the post-cutting management process. However, in the cutting management process of the present invention, the relative air humidity and watering frequency are gradually reduced from the early, middle and late stages of cutting, so that it can adapt to the variable demand for humidity before the rooting and survival of Robinia pseudoacacia pinnate leaves, and it is also beneficial to improve the survival rate of cutting and transplanting. Specifically, the early stage of cutting, that is, within the 1st to 30th day of cutting, is the critical period for the formation of adventitious roots of pinnate leaf cuttings. At this time, the moisture content requirement is relatively high, and the relative air humidity is controlled between 80% and 85%. The nutrient cup is immersed in the pot once every 2 to 4 days, preferably every 3 days. In the middle period of cutting, i.e., the 31st to 60th day of cutting, the root system grows and develops, and the branches and leaves begin to flourish, so the root system can absorb water autonomously. At this time, the relative humidity of the air should be controlled at 75-80%, and the number of immersions should be gradually reduced. For example, the nutrient cup should be immersed once every 5-7 days or when the river sand in the nutrient cup turns white. It should be noted that the whitening of the river sand in the nutrient cup is a sign of lack of water in the substrate. If the humidity is not reduced and the watering frequency is not reduced in the middle period of cutting, the root system of the plant is easy to rot, causing the death of the Robinia pseudoacacia seedlings. In the late stage of cutting, that is, 61 days after cutting and before transplanting, the locust seedlings have survived, the root system is well developed, and the ability to absorb water is stronger. At this time, the relative humidity of the air should be reduced to 50-60%, and the number of immersion times should be gradually reduced again. When the river sand in the nutrient cup turns white, the nutrient cup can be immersed in the pot once. If the humidity is not reduced and the frequency of watering is not reduced, the plants are prone to leggy growth and root rot, resulting in the death of the locust seedlings or a low survival rate after leaving the nursery.

[0051] As for the temperature control during the cutting management process, it is generally controlled within the range of 25-28℃. In addition, the influence of sunlight should also be paid attention to during the cutting process. The sunlight should be sufficient and gentle, not too hot, otherwise the seedlings will be sunburned. For example, on the 1st to 30th day of cutting, use a 70% shade net at a height of 1.5m to shade for 4 to 5 hours from 10:00 to 15:00 every day on sunny days. On the 31st to 60th day of cutting, use a 70% shade net at a height of 1.5m to shade for 2 to 4 hours from 11:00 to 15:00 every day on sunny days. After 61 days of cutting, the surviving seedlings basically have new branches and new compound leaves, and their demand for light has increased and they have a certain resistance. You can choose whether to shade according to the weather conditions.

[0052] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein, in step (1), the matrix includes the lower layer of nutrient soil and the upper layer of river sand. Robinia pseudoacacia prefers deep, fertile, loose, moist silt soil and sandy loam, so the present invention preferably uses a matrix composed of nutrient soil and river sand. The lower nutrient soil is loose, has a strong ability to store water and nutrients, and provides a good rooting environment, while the upper river sand plays a certain compaction and support role. More preferably, the nutrient soil is humus soil, which is formed by the dead branches and leaves of trees in the topsoil layer of the forest after a long period of decay and fermentation, and can provide Robinia pseudoacacia cuttings with richer nutrition. The river sand is fine river sand with a particle size of 1 to 1.5 mm. Preferably, the volume ratio of the nutrient soil to the river sand is 7:1 to 9:1. Further preferably, the volume ratio of the nutrient soil to the river sand is 8:1.

[0053] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein, in step (1), the cutting bed selects a bed body with good water storage and drainage functions. In addition, one week before cutting, 50% carbendazim wettable powder or other fungicides are added to the nutrient soil and river sand respectively, and 50 grams of 50% carbendazim powder or other fungicides are evenly mixed into each cubic meter of the matrix, and covered with a film for 3 to 4 days, and the film is removed. Three days before cutting, the cutting bed is disinfected with 0.5% potassium permanganate or other fungicides. Disinfection of the matrix and the cutting bed can kill miscellaneous bacteria and prevent the cutting cut from rotting. Since the nutrient cup is also subjected to a basin immersion treatment before cutting, the fungicide remaining in the cutting bed will also flow out, reducing the impact of drug residues on the cuttings. It can be seen that the technical solution of the present invention can clean the sand body in the cutting bed at any time to ensure the quality of water, liquid medicine, etc. for cutting, and effectively avoid the pollution of the environment by the applied drugs, reagents, etc. through wastewater recovery and treatment.

[0054] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein, in step (1) and step (4), the specific operation of supplying water to the nutrient cup by the immersion pot method is: injecting water into the sand body of the cutting bed to raise the water level to 1 / 3 of the height of the nutrient cup, and draining the water after the substrate is infiltrated.

[0055] According to the above-described Robinia pseudoacacia cutting propagation method, wherein, in step (2), the cuttings are pinnate compound leaf cuttings with basal protrusions on the leaf axis. According to the inventor's research, it is shown that the rooting rate and survival rate of pinnate compound leaf cuttings with basal protrusions on the leaf axis are higher. This may be because the basal protrusions store more nutrients and can provide more sufficient nutrition for the cuttings before and during rooting. Preferably, the diameter of the cuttings is greater than or equal to 1.5 mm. Cuttings with a diameter of less than 1.5 mm do not store enough nutrients and are prone to dryness and death after cutting, and the survival rate of the cuttings and the quality of the bred seedlings become lower. Therefore, when the cutting material is sufficient, this part of the material can be discarded.

[0056] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein, in step (2), the removed leaflets retain at least 1 mm of the leaf petiole, and retaining part of the petiole is to avoid damaging the leaf axis and axillary buds and also to reduce the probability of bacterial infection.

[0057] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein step (2) can specifically prepare cuttings according to the following steps: from May to mid-June each year, select robust, disease- and insect-free Robinia pseudoacacia branches of the current year, pick the pinnate compound leaves from the base of the rachis, and then cut them into 10-15 cm cuttings from the base to the tip, and the cutting position is 0.4-0.6 cm from the upper end of the leaflet to be retained on the rachis, preferably 0.5 cm, so that each cutting can basically have 3-4 pairs of leaflets, that is, 10-15 cm in length. It should be noted that the length of the cuttings in the present invention is measured by the length of the rachis of the cuttings. Then cut off 1-2 pairs of leaflets near the base of each cutting, retain 2 pairs of leaflets near the tip, and then cut off 1 / 3-1 / 2 of the retained leaflets near the tip, and retain 1 / 2-2 / 3 of the retained leaflets near the petiole. The above pruning method can ensure that more cuttings are obtained when the cutting materials are scarce. The prepared Robinia pseudoacacia pinnate compound leaf cuttings are as follows: Figure 1 and Figure 2 As shown, Figure 1 The middle left picture shows a cutting of a Robinia pseudoacacia pinnate leaf with a basal protuberance. Figure 1 The middle right picture shows a Robinia pseudoacacia pinnate leaf cutting without the basal protuberance.

[0058] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein, in step (3), 1 / 3 to 1 / 2 of the base of the cutting is dipped in the rooting agent for 3 to 5 seconds, dried in the shade and inserted into the matrix, and the cutting depth is 1 / 3 to 1 / 2 of the length of the cutting, that is, 5 to 6 cm. Dipping in the rooting agent can induce the cutting to produce adventitious roots after cutting. Preferably, the rooting agent is a mixed aqueous solution of 1000 mg / kg indolebutyric acid and naphthaleneacetic acid, and the rooting agent formed by this mixture of ingredients has a stronger root-inducing effect. More preferably, the mass ratio of the indolebutyric acid to the naphthaleneacetic acid is 2:1, and the rooting agent in this ratio range has the best root-inducing effect.

[0059] According to the above-mentioned Robinia pseudoacacia cutting propagation method, in step (3), before cutting, a hole is made on the substrate with a stick, the diameter of the stick is greater than or equal to the maximum width of the cutting rachis, and then the cutting is inserted into the substrate, and the cutting and the substrate around the hole are compacted. Since the rachis of the Robinia pseudoacacia pinnate leaf cuttings are relatively thin and weak, direct cutting may cause the rachis to be injured. Therefore, before cutting, a thin stick with a thickness similar to the rachis is used to make a hole, which can effectively protect the rachis of the cutting and improve the survival rate.

[0060] According to the above-mentioned Robinia pseudoacacia cutting propagation method, wherein step (4) specifically comprises the following steps:

[0061] ① Days 1 to 30 of cutting: maintain the ambient temperature at 25 to 28°C and the relative humidity at 80 to 85%. Water the nutrient cups every 2 to 4 days by the immersion method, and then keep the sand in the cutting bed moist. On the 10th to 14th day, use 900 to 1100 times diluted 50% carbendazim wettable powder for sterilization and disinfection by immersion, and then slowly rinse the sand in the cutting bed with water to reduce drug residues. On the 14th to 16th day, replace the water immersion treatment with 450 to 550 mg / kg indolebutyric acid aqueous solution to promote the formation of adventitious roots of cuttings. On the 23rd to 25th day of cutting, replace the water immersion treatment with 450 to 550 mg / kg naphthaleneacetic acid aqueous solution to strengthen the roots.

[0062] ② Day 31 to 60 of cutting: maintain the ambient temperature at 25 to 28°C and the relative humidity at 75 to 80%. Water the nutrient cups by immersion every 5 to 7 days or when the river sand in the nutrient cups turns white, and then keep the sand in the cutting bed moist. On the 44th to 46th day, replace the water immersion pot treatment with nutrient solution I, which includes 18 to 22% urea, 10 to 14% potassium dihydrogen phosphate, 16 to 20% potassium chloride, and the balance is water. The nutrient solution I can effectively promote the growth and development of the root system. On the 54th to 56th day, nutrient solution II was used instead of the water-immersion pot treatment. The nutrient solution II included 28-32% urea, 8-12% potassium dihydrogen phosphate, 13-17% potassium chloride, 2.5-3.5% magnesium sulfate, 0.4-0.6% zinc sulfate, and the balance was water. The nutrient solution II could effectively promote the growth of the root system, while promoting nitrogen metabolism and the plant's assimilation of carbon dioxide, and promoting the growth of branches and leaves.

[0063] ③ From the 61st day after cutting to before transplanting: maintain the ambient temperature at 25-28°C and the relative humidity at 50-60%. When the river sand in the nutrient cup turns white, water the nutrient cup by dipping the pot, and then keep the sand in the cutting bed moist. When the Robinia pseudoacacia seedlings have 2-4 side branches, each of which has 3-6 compound leaves, and the roots grow out of the nutrient cup, cut off the roots outside the cup, and then transplant them from the cutting bed to the field for planting.

[0064] According to the research of the present invention, it is shown that applying different rooting agents, indolebutyric acid and naphthaleneacetic acid, respectively at different times can significantly promote the rooting and root strengthening of pinnate compound leaf cuttings. Applying the above-mentioned nutrient solution I on the 44th to 46th day, preferably on the 45th day, has the effect of promoting root growth and development. Applying the above-mentioned nutrient solution II on the 54th to 56th day, preferably on the 55th day, can promote the root system to be strong, and at the same time promote nitrogen metabolism and the assimilation of carbon dioxide by the plant, and promote the growth of branches and leaves. Preferably, the nutrient solution I includes 20% urea, 12% potassium dihydrogen phosphate, 18% potassium chloride, and the balance is water, and the nutrient solution II includes 30% urea, 10% potassium dihydrogen phosphate, 15% potassium chloride, 3% magnesium sulfate, 0.5% zinc sulfate, and the balance is water.

[0065] In the above-mentioned cutting seedling raising process, the present invention can flexibly supply water, growth hormone, fertilizer, etc. and sterilize and disinfect the roots of the cuttings by observing the rooting and leafing of the substrate and cuttings, which can effectively improve the survival rate of the cuttings and the quality of the seedlings.

[0066] The present invention is described in detail below with reference to the embodiments and the accompanying drawings.

[0067] Example 1

[0068] A cutting propagation method for Robinia pseudoacacia specifically comprises the following steps:

[0069] (1) Matrix and slotting bed treatment

[0070] Cuttings are carried out in an automated controlled greenhouse.

[0071] The matrix is ​​fine river sand and humus soil with a particle size of 1 to 1.5 mm. The bed should have good water storage and drainage functions.

[0072] One week before cutting, add 50% carbendazim wettable powder to humus soil and river sand respectively, mix 50g of 50% carbendazim powder evenly into 1 cubic meter of substrate, cover with film for 3-4 days, and then remove the film. Three days before cutting, disinfect the cutting bed with 0.5% potassium permanganate.

[0073] Spread the disinfected river sand in the bed at a height of more than 10 cm. The nutrient cup is 8 cm × 8 cm, 10 cm high, and has a water hole at the bottom. First fill the nutrient cup with nutrient soil to a height of about 8 cm, and then fill it with river sand to a height of about 1 cm. Place the nutrient cups filled with substrate neatly on the river sand in the bed, and press the river sand slightly when placing the nutrient cups to make the nutrient cups stable. The day before cutting, add water to the bed, and the water level should be 1 / 3 of the height of the nutrient cups. After the substrate in the cups is soaked, drain the water, keep the river sand in the bed moist, and dry the nutrient cups in the shade for about 12 hours.

[0074] (2) Cutting collection and processing

[0075] The collection time is May 26, 2022, and it can be planted as soon as it is collected.

[0076] Break off the pinnate leaves of Robinia pseudoacacia from the branches, retain the protrusions at the base of the rachis, and cut cuttings from the base to the tip of the newly picked pinnate leaves of Robinia pseudoacacia. Each cutting contains 3 to 4 pairs of leaflets, and the cutting position is 0.5 cm above the petiole of the leaves. The thinner part of the rachis at the tip of the pinnate leaves is not used. Cut off 1 to 2 pairs of leaflets at the base of each cutting, retain 1mm of the petiole of the leaf, retain 2 pairs of leaflets at the tip, and then cut off 1 / 2 to 2 / 3 of each leaf of the retained leaflets, retaining 1 / 3 to 1 / 2 of each leaf.

[0077] Soak the lower part of the cuttings in a rooting agent for 3 seconds, the soaking height is 1 cm above the upper end of the cut leaves, take out and dry in the shade. The rooting agent is 1000 mg / kg of indolebutyric acid + naphthaleneacetic acid (2:1).

[0078] (3) Cuttings

[0079] Before cutting, use a small wooden stick to poke holes in the substrate, with a depth of 5 to 6 cm and a diameter slightly larger than or equal to the maximum width of the cutting leaf axis. Insert the cuttings dipped in rooting agent into the substrate, compact it, and then spray it in the air to keep it moist.

[0080] (4) Management after cutting

[0081] ① Cutting 1 to 30 days

[0082] Maintain the ambient temperature at 25-28℃ and the relative humidity at 80-85%. Use a 70% shade net at a height of 1.5m for 4-5 hours from 10:00 to 15:00 on sunny days.

[0083] The nutrient cups are soaked once every 3 days. On the 12th day, a 1000-fold diluted 50% carbendazim wettable powder is used for sterilization and disinfection. After the sterilization and disinfection, the river sand in the bed is slowly rinsed with tap water to reduce drug residues. On the 15th day, 500 mg / kg of indolebutyric acid, a rooting agent, is used for soaking to promote the formation of adventitious roots of cuttings. On the 24th day, 500 mg / kg of naphthylacetic acid, a rooting agent, is used for soaking to strengthen the roots. Tap water is used for other soaking times. Each time the pot is soaked, drain the water after the upper layer of river sand in the nutrient cup is moistened, and then keep the river sand in the bed moist. Figure 3 The figure shows the rooting of the cuttings on the 35th day after the cuttings of this embodiment.

[0084] ② Cutting 31 to 60 days

[0085] Maintain the ambient temperature at 25-28℃ and the relative humidity at 75-80%. Use a 70% shade net at a height of 1.5m for shading for 2-4 hours from 11:00 to 15:00 on sunny days.

[0086] Gradually reduce the number of times you soak the pots, and soak the nutrient cups once every 5 to 7 days or when the river sand in the nutrient cups turns white. On the 45th day, use nutrient solution I to soak the pots. Nutrient solution I: 20% urea, 12% potassium dihydrogen phosphate, 18% potassium chloride, to promote root growth and development. On the 55th day, use nutrient solution II to soak the pots. Nutrient solution II: 30% urea, 10% potassium dihydrogen phosphate, 15% potassium chloride, 3% magnesium sulfate, 0.5% zinc sulfate, to promote strong roots, nitrogen metabolism and the plant's assimilation of carbon dioxide, and promote the growth of branches and leaves. Use tap water for other soaking times. Drain the water each time the upper river sand in the nutrient cup is moistened, and then keep the river sand in the bed moist.

[0087] ③61 days later

[0088] Maintain the ambient temperature at 25-28°C and the relative humidity at 50-60%.

[0089] Gradually reduce the number of times the pot is dipped, and when the river sand in the nutrient cup turns white, dip the nutrient cup once. When there are 2 to 4 side branches on the branch, and each side branch has 3 to 6 compound leaves, observe the lower part of the nutrient cup at the same time. When the root system grows out of the nutrient cup, cut off the root system outside the nutrient cup and transplant it into the field for planting.

[0090] Comparative Example 1

[0091] Comparative Example 1 During the post-cutting management process, a 1000-fold diluted 50% carbendazim wettable powder was used for sterilization and disinfection on the 12th day, and the rest were treated with tap water, i.e., no rooting agent indolebutyric acid, naphthaleneacetic acid, nutrient solution I and II were used for pot soaking. The substrate and cutting bed treatment, cutting, seedling environment, and post-cutting management method were the same as those in Example 1. When there were 2 to 4 side branches on the branch, and 2 to 5 compound leaves on each side branch, the lower part of the nutrient cup was observed at the same time. When the root system grew out of the nutrient cup, the root system outside the nutrient cup was cut off and transplanted into the field for planting.

[0092] Comparative Example 2

[0093] A Robinia pseudoacacia cutting propagation method comprises the following steps:

[0094] (1) Matrix and slotting bed treatment

[0095] Cuttings are carried out in an automated controlled greenhouse.

[0096] The substrate is fine river sand and humus soil with a particle size of 1 to 1.5 mm. The planting bed is an ordinary planting bed with a seedling tray, and there are multiple water holes at the bottom of the seedling tray.

[0097] One week before cutting, add 50% carbendazim wettable powder to humus soil and river sand respectively, mix 50g of 50% carbendazim powder evenly into 1 cubic meter of substrate, cover with film for 3-4 days, and then remove the film. Three days before cutting, disinfect the cutting bed with 0.5% potassium permanganate.

[0098] First, fill the seedling tray with nutrient soil to a height of about 8 cm, and then fill it with river sand to a height of about 1 cm. Then place the seedling tray on the planting bed for later use.

[0099] (2) Cutting collection and processing

[0100] The collection time is May 26, 2022, and it can be planted as soon as it is collected.

[0101] Break off the pinnate leaves of Robinia pseudoacacia from the branches, retain the protrusions at the base of the rachis, and cut the cuttings from the base to the tip of the newly picked pinnate leaves of Robinia pseudoacacia. Each cutting contains 3 to 4 pairs of leaflets, and the cutting position is 0.5 cm above the petiole of the leaves. The thinner part of the rachis at the tip of the pinnate leaves is not used. Cut off 1 to 2 pairs of compound leaves at the base of each cutting, retain 1 mm of the petiole of the leaf blade, and retain 2 pairs of leaflets at the tip.

[0102] Soak the lower part of the cuttings in a rooting agent for 3 seconds, the soaking height is 1 cm above the upper end of the cut leaves, take out and dry in the shade. The rooting agent is 1000 mg / kg of indolebutyric acid + naphthaleneacetic acid (2:1).

[0103] (3) Cuttings

[0104] Before cutting, use a small wooden stick to poke holes in the substrate, with a depth of 5 to 6 cm and a diameter slightly larger than or equal to the maximum width of the cuttings' leaf axis. Insert the cuttings dipped in the rooting agent into the substrate, compact them, and then spray them in the air for moisture. At the same time, water the cuttings directly in the seedling tray, and stop when the substrate is thoroughly watered.

[0105] (4) Management after cutting

[0106] ① Cutting 1 to 30 days

[0107] Maintain the ambient temperature at 25-28℃ and the relative humidity at 80-85%. Use a 70% shade net at a height of 1.5m for 4-5 hours from 10:00 to 15:00 on sunny days.

[0108] Water the seedling tray once every 3 days, and stop watering when the substrate is thoroughly watered. Add 1000 times diluted 50% carbendazim wettable powder when watering on the 12th day. Add 500 mg / kg of indolebutyric acid, a rooting agent, when watering on the 15th day. Add 500 mg / kg of naphthaleneacetic acid, a rooting agent, when watering on the 24th day. The dosage of 50% carbendazim wettable powder, indolebutyric acid, and naphthaleneacetic acid is the same as in Example 1.

[0109] ② Cutting 31 to 60 days

[0110] Maintain the ambient temperature at 25-28℃ and the relative humidity at 75-80%. Use a 70% shade net at a height of 1.5m for shading for 2-4 hours from 11:00 to 15:00 on sunny days.

[0111] Gradually reduce the number of waterings, and water directly every 5 to 7 days or when the river sand in the seedling tray turns white. Add nutrient solution I: 20% urea, 12% potassium dihydrogen phosphate, 18% potassium chloride when watering on the 45th day. Add nutrient solution II: 30% urea, 10% potassium dihydrogen phosphate, 15% potassium chloride, 3% magnesium sulfate, 0.5% zinc sulfate when watering on the 55th day. The dosage of nutrient solution I and nutrient solution II is the same as in Example 1.

[0112] ③61 days later

[0113] Keep the ambient temperature at 25-28℃ and the relative humidity at 50-60%. Water directly when the river sand in the seedling tray turns white.

[0114] When there are 1 to 3 side branches on the branch and 1 to 5 compound leaves on each side branch, observe the lower part of the nutrient cup at the same time. When the roots grow out of the nutrient cup, cut off the roots outside the nutrient cup and move to the field for planting.

[0115] In comparative example 2, the cuttings fell over, dried up and died within 20 days of cutting. The rooting rate was counted on the 35th day of cutting, and it was found that the rooting rate of the pinnate compound leaf cuttings with basal protrusions was only 36.5%, and the rooting rate of the pinnate compound leaf cuttings without basal protrusions was only 19.15%.

[0116] Comparative Example 3

[0117] Robust, disease-free and insect-free Robinia pseudoacacia branches of the current year were collected, and the pinnate compound leaves on the Robinia pseudoacacia branches were used as cuttings in Example 1. The remaining Robinia pseudoacacia branches were used as cutting materials for softwood cuttings, and a total of 5200 softwood cuttings were obtained. It should be noted that when only Example 1 is performed, it is not necessary to collect Robinia pseudoacacia branches at the same time, and only the pinnate compound leaves can be collected.

[0118] In comparative example 3, after the pinnate leaves were removed from the Robinia pseudoacacia branches, they were cut into cuttings with a length of 10 to 12 cm and a diameter of 0.3 to 1.0 cm. The cutting position was 1.0 to 1.2 cm above the cut bud, and 2 to 4 leaflets in the pinnate leaf at the upper end were retained, and the remaining leaves were removed. A total of 5,200 cuttings were obtained. The lower part of the cuttings was soaked in a rooting agent for 3 seconds, and the soaking height was 1 / 3 to 1 / 2 of the base of the cuttings, and then taken out and slightly dried in the shade. The rooting agent was 1000 mg / kg of indolebutyric acid + naphthaleneacetic acid (2:1).

[0119] The treatment of substrate and cutting bed, cutting, nursery environment, and post-cutting management methods are the same as those in comparative example 2. When there are 3 to 4 side branches on the branch, and 4 to 6 compound leaves on each side branch, the lower part of the nutrient cup is observed at the same time. When the root system grows out of the nutrient cup, the root system outside the nutrient cup is cut off and transplanted into the field.

[0120] The cuttings used in Example 1 and Comparative Examples 1 to 3 were all selected from the same forest farm, the same variety, and the same batch of Robinia pseudoacacia mother plants. The picked Robinia pseudoacacia pinnate leaves were randomly distributed to each group, and the cuttings and post-cutting management were completed under the same seedling environment. 15,000 cuttings were cut from each group in Example 1 and Comparative Examples 1 to 2, each of which included 5,000 cuttings with protrusions at the base of the pinnate leaves and 10,000 cuttings without protrusions at the base of the pinnate leaves. The cuttings with protrusions at the base of the pinnate leaves were cut together in each group. Comparative Example 3 is a tender branch cutting cut from the branches after the pinnate leaves were broken off in Example 1, and a total of 5,200 cuttings were obtained. The cutting rooting rate, seedling raising period, seedling branch and leaf growth, survival rate, etc. of Example 1 and Comparative Examples 1 to 3 were statistically analyzed, and the results are shown in Table 1. The rooting rate was calculated on the 35th day after cutting, the branch and leaf growth was calculated on the 70th day after cutting, and the survival rate was calculated on the 20th day after transplanting into the field.

[0121] Table 1. Cutting rooting rate, seedling raising period, seedling branch and leaf growth, and survival rate of Robinia pseudoacacia cutting propagation methods of Example 1 and Comparative Examples 1 to 3

[0122]

[0123] As can be seen from Table 1 Example 1, the present invention uses Robinia pseudoacacia pinnate leaves as cutting materials for cutting propagation, with a rooting rate of more than 85.45% and a survival rate of more than 92.16%, which fully demonstrates that the cutting propagation method of the present invention is feasible. The present invention uses Robinia pseudoacacia pinnate leaves as cutting materials, breaking through the selection range of Robinia pseudoacacia cutting propagation materials in the past.

[0124] From the statistical data of Example 1 and Comparative Example 3 in Table 1, it can be seen that, using the cutting propagation method of the present invention, although the rooting rate and survival rate of the pinnate compound leaf cuttings without base protrusions are lower than those of softwood cuttings, the rooting rate and survival rate of the pinnate compound leaf cuttings with base protrusions are slightly higher than those of softwood cuttings. Therefore, in general, using the cutting propagation method of the present invention, the rooting rate is above 85.45%, and the survival rate is above 92.16%. Compared with the traditional softwood cutting method, the rooting rate and survival rate of the cuttings are almost the same. Importantly, the same batch of branches taken from the mother plant of Robinia pseudoacacia are used to cut cuttings with their pinnate compound leaves and branches, respectively, and the number of pinnate compound leaf cuttings obtained is 2.88 times the number of softwood cuttings. The total number of seedlings obtained by pinnate compound leaf cuttings is 11,812, which is 2.7 times the number of seedlings obtained by softwood cuttings. Therefore, if the mother material is less, the number of pinnate leaves is much larger than that of tender branches. The cutting propagation method of the present invention can greatly increase the number of cutting materials and reduce the damage to the mother plant. In the same time, fast and efficient propagation can be achieved, which is convenient for market promotion. This is far beyond the reach of the traditional tender branch cutting method.

[0125] Furthermore, the present invention achieves the purpose of using Robinia pseudoacacia pinnate leaves as materials for cutting propagation, and also finds the following rules: Among them, the material with the protrusions at the base of the pinnate leaves as cuttings is the best choice, and the effect is better than the pinnate leaves without base protrusions. Specifically, from the comparison of the group with base protrusions and the group without base protrusions in Example 1, it can be found that the pinnate leaves with base protrusions are used as cutting materials. The rooting rate is 90.42%, and the survival rate is 95.2%, which is significantly higher than the rooting rate and survival rate of the pinnate leaves without base protrusions. The number of seedling branches and new compound leaves is also significantly higher than that of the pinnate leaves without base protrusions, which significantly improves the seedling raising efficiency and the possibility of seedling survival. Similarly, the pinnate leaves with base protrusions in Comparative Examples 1 and 2 also have a better cutting effect than the pinnate leaves without base protrusions.

[0126] By comparing Example 1 with Comparative Example 1, it can be found that in the process of post-cutting management, adding the rooting agent and nutrient solution used in Example 1 of the present invention for pot immersion treatment in an appropriate time period can greatly improve the rooting rate of cuttings. Specifically, the rooting rate of the pinnate compound leaf cuttings with basal protrusions in Example 1 is 90.42%, and the rooting rate of the pinnate compound leaf cuttings without basal protrusions is 82.96%, both of which are significantly higher than those in Comparative Example 1. The survival rate of the pinnate compound leaf cuttings with basal protrusions in Example 1 is 95.2%, and the survival rate of the pinnate compound leaf cuttings without basal protrusions is 90.5%. At the same time, the seedling raising period of Example 1 is shortened by 10 to 20 days compared with that of Comparative Example 1, and the number of seedling branches and new compound leaves is also significantly higher than that of Comparative Example 1, which significantly improves the seedling raising efficiency and the possibility of seedling survival.

[0127] Comparative Example 2 is a cutting propagation on a common inserting bed with a seedling tray. The seedling raising environment, cutting, medicament, rooting agent, fertilization treatment, and post-cutting management are the same as those in Example 1. The difference is that 2 pairs of complete leaflets are retained on the cuttings, and the method of immersion pots is not used in the whole process. The humidity of the environment and the substrate is maintained by aerial spraying and direct watering. Within 20 days of cutting, it was found that the cuttings all showed local lodging after each spraying and watering, and the thin and weak cuttings were the most obvious. After the support, the cuttings still dried up and died one after another, and the surrounding seedlings were affected during the operation, and the drying phenomenon appeared one after another, and the death area continued to expand. It is considered that the pinnate compound leaf cuttings are relatively thin and weak, and the strong water flow during watering and spraying will cause the substrate to be lost, and the cuttings will fall. The support process is time-consuming and laborious, and the effect is not ideal, and secondary damage is caused to the entire seedling bed, and the quiet and stable environment required for the cuttings to take root cannot be guaranteed. Moreover, retaining two pairs of leaves may consume a large amount of nutrients stored in the cuttings, and the nutrients are easily exhausted during the rooting process, resulting in the death of the pinnate compound leaf cuttings. Therefore, the rooting rate of the pinnate compound leaf cuttings with base protrusions in Comparative Example 2 is only 36.5%, and the rooting rate of the pinnate compound leaf cuttings without base protrusions is 19.15%. Compared with Example 1, the seedling raising period of Comparative Example 2 is longer, and the root system and branches and leaves of the cultivated seedlings are also less.

[0128] In summary, the Robinia pseudoacacia pinnate compound leaf cuttings selected by the present invention, as well as the management techniques and measures adopted, significantly improve the rooting rate, survival rate and seedling quality of the cuttings, shorten the seedling raising cycle, and have obvious effects.

Claims

1. A method for propagating Robinia pseudoacacia by cuttings, characterized in that: The following steps are involved: (1) Substrate and cutting bed treatment: Sterilize and disinfect the substrate into a nutrient cup, and then place it on the sterilize and disinfect sand body of the cutting bed. One day before cutting, water the nutrient cup by immersion pot method, and then dry the nutrient cup in the shade for 10 to 15 hours. (2) Cutting collection and processing: From May to mid-June each year, collect healthy, disease-free and insect-free pinnate compound leaves of Robinia pseudoacacia of the current year, and then cut them into 10-15 cm long cuttings, retaining 1 / 2-2 / 3 of the two pairs of leaflets near the tip of the leaf axis near the petiole, remove the other leaflets, and plant them as soon as they are collected; (3) Cutting: Dip the treated base of the cutting into a rooting agent, dry it in the shade, and then insert it into the substrate; (4) Management after cutting: natural light, keep the ambient temperature at 25-28°C; ① 1st to 30th day after cutting: keep the relative humidity of the air at 80-85%, water the nutrient cup by immersion method every 2-4 days, during which at least one time of watering by immersion method is added with fungicide, and at least one time of watering by immersion method is added with rooting agent; ② 31st to 60th day after cutting: keep the relative humidity of the air at 75-80%, and add river sand in the nutrient cup every 5-7 days or When the water turns white, the nutrient cup is watered by the immersion pot method, and nutrients are added at least once during the immersion pot watering; ③ From the 61st day of cutting to before transplanting: the relative humidity of the ambient air is maintained at 50-60%, and the nutrient cup is watered by the immersion pot method every 8-10 days or when the river sand in the nutrient cup turns white. When there are 2-4 side branches on the branch, each side branch has 3-6 compound leaves, and the root system grows out of the nutrient cup, it can be moved from the cutting bed to the field for planting.

2. The cutting propagation method of Robinia pseudoacacia according to claim 1, characterized in that: In step (1), the matrix includes nutrient soil in the lower layer and river sand in the upper layer.

3. The cutting propagation method of Robinia pseudoacacia according to claim 2, characterized in that: In step (1), the nutrient soil is humus soil, and the river sand is fine river sand with a particle size of 1 to 1.5 mm.

4. The cutting propagation method of Robinia pseudoacacia according to claim 3, characterized in that: In step (1), the volume ratio of the nutrient soil to the river sand is 7:1 to 9:

1.

5. The cutting propagation method of Robinia pseudoacacia according to claim 4, characterized in that: In step (1), the volume ratio of the nutrient soil to the river sand is 8:

1.

6. The cutting propagation method of Robinia pseudoacacia according to claim 1, characterized in that: In step (1) and step (4), the specific operation of supplying water to the nutrient cup by the immersion basin method is: injecting water into the sand body of the insert bed to raise the water level to 1 / 3 of the height of the nutrient cup, and draining the water after the substrate is soaked.

7. The cutting propagation method of Robinia pseudoacacia according to claim 1, characterized in that: In step (2), the cuttings are pinnate compound leaf cuttings with leaf axes having basal protrusions.

8. The cutting propagation method of Robinia pseudoacacia according to claim 7, characterized in that: In step (2), the diameter of the cutting strip is greater than or equal to 1.5 mm.

9. The cutting propagation method of Robinia pseudoacacia according to claim 1, characterized in that: In step (2), the removed leaflets retain at least 1 mm of the leaf petiole.

10. The Robinia pseudoacacia cutting propagation method according to claim 1, characterized in that: Step (2) specifically includes the following steps: from May to mid-June each year, selecting robust, disease- and insect-free Robinia pseudoacacia branches of the current year, picking the pinnate compound leaves from the base of the rachis, and then cutting them into 10-15 cm cuttings from the base to the tip, the cutting position being 0.4-0.6 cm above the upper end of the leaflet that needs to be retained on the rachis, the cutting having 3-4 pairs of leaflets after cutting, and then cutting off 1-2 pairs of leaflets near the base of the cutting, retaining 2 pairs of leaflets near the tip, and then cutting off 1 / 3-1 / 2 of the retained leaflet near the tip, and retaining 1 / 2-2 / 3 of the retained leaflet near the petiole.

11. The cutting propagation method of Robinia pseudoacacia according to claim 1, characterized in that: In step (3), 1 / 3 to 1 / 2 of the base of the cutting is dipped into the rooting agent for 3 to 5 seconds, dried in the shade and then inserted into the matrix, with the cutting depth being 1 / 3 to 1 / 2 of the length of the cutting.

12. The cutting propagation method of Robinia pseudoacacia according to claim 11, characterized in that: In step (3), the rooting agent is a mixed aqueous solution of 1000 mg / kg indolebutyric acid and naphthylacetic acid.

13. The cutting propagation method of Robinia pseudoacacia according to claim 12, characterized in that: In step (3), the mass ratio of the indolebutyric acid to the naphthylacetic acid is 2:

1.

14. The cutting propagation method of Robinia pseudoacacia according to claim 1, characterized in that: In step (3), before cutting, a hole is pierced in the matrix with a stick, the diameter of the stick is greater than or equal to the maximum width of the leaf axis of the cutting, and then the cutting is inserted into the matrix, and the cutting and the matrix around the hole are compacted.

15. The cutting propagation method of Robinia pseudoacacia according to claim 1, characterized in that: Step (4) specifically includes the following steps: ① On the 1st to 30th day of cutting: maintain the ambient temperature at 25 to 28° C., the relative air humidity at 80 to 85%, water the nutrient cups by immersion every 2 to 4 days, sterilize and disinfect the nutrient cups by immersion using 900 to 1100 times diluted 50% carbendazim wettable powder on the 10th to 14th day, then slowly rinse the sandy bed with water, replace the water immersion with 450 to 550 mg / kg indolebutyric acid aqueous solution on the 14th to 16th day, and replace the water immersion with 450 to 550 mg / kg naphthaleneacetic acid aqueous solution on the 23rd to 25th day of cutting; ② Day 31 to 60 of cutting: maintain the ambient temperature at 25 to 28° C., the relative humidity at 75 to 80%, water the nutrient cups by immersion every 5 to 7 days or when the river sand in the nutrient cups turns white, replace the water immersion pot treatment with nutrient solution I on the 44th to 46th day, the nutrient solution I includes 18 to 22% urea, 10 to 14% potassium dihydrogen phosphate, 16 to 20% potassium chloride, and the balance is water, replace the water immersion pot treatment with nutrient solution II on the 54th to 56th day, the nutrient solution II includes 28 to 32% urea, 8 to 12% potassium dihydrogen phosphate, 13 to 17% potassium chloride, 2.5 to 3.5% magnesium sulfate, 0.4 to 0.6% zinc sulfate, and the balance is water; ③ From the 61st day of cutting to before transplanting: maintain the ambient temperature at 25-28°C and the relative humidity at 50-60%, water the nutrient cups by immersion method every 8-10 days or when the river sand in the nutrient cups turns white, when the Robinia pseudoacacia seedlings have 2-4 side branches, each of which has 3-6 compound leaves, and the roots grow out of the nutrient cups, cut off the roots outside the cups, and then the seedlings can be transplanted from the cutting bed into the field for planting.

16. The cutting propagation method of Robinia pseudoacacia according to claim 15, characterized in that: In step (4), the nutrient solution I includes 20% urea, 12% potassium dihydrogen phosphate, 18% potassium chloride, and the balance is water, and the nutrient solution II includes 30% urea, 10% potassium dihydrogen phosphate, 15% potassium chloride, 3% magnesium sulfate, 0.5% zinc sulfate, and the balance is water.

17. The cutting propagation method of Robinia pseudoacacia according to claim 15, characterized in that: In step (4), on the 1st to 30th day of cutting: use a 70% shade net at a height of 1.5 m to provide shade for 4 to 5 hours from 10:00 to 15:00 on sunny days; on the 31st to 60th day of cutting: use a 70% shade net at a height of 1.5 m to provide shade for 2 to 4 hours from 11:00 to 15:00 on sunny days.

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