Efficient rooting technique for high efficiency of cutting propagation of longan

Abstract

The application discloses a high-efficiency induction longan rooting technology for cutting breeding and belongs to the technical field of nursery stock breeding. The method comprises the following steps: 1) taking field soil, nutrient soil, vermiculite and rooting powder to be mixed and prepared into a substrate; 2) selecting old and mature branches of longan strong tree species for years, removing bark with a width of 2-4 mm and a vascular cambium with a ring cutting knife, and exposing xylem outside; 3) using transparent plastic film to contain wet substrate and tightly wrap the ring stripping wound; 4) removing the top of the treated branch; 5) when roots emerge from the substrate and can be observed through the plastic film, the branch can be cut and transplanted. In the prior art, longan propagation is mainly based on grafting, and there is no breakthrough in cutting propagation technology, and direct cutting is extremely difficult to survive. The application efficiently induces longan branch rooting (aerial rooting), can not only break the barrier of longan cutting propagation difficulty, but also can lay a foundation for subsequent longan ex situ regeneration and genetic transformation exploration work.

Description

Technical Field

[0001] This invention belongs to the field of seedling propagation technology, specifically relating to a highly efficient technique for inducing longan rooting for cutting propagation. Background Technology

[0002] Longan ( Dimocarpus longan Longan (Lour.) is an evergreen tree belonging to the Sapindaceae family and the Longan genus. It is one of the important tropical and subtropical fruit trees in southern China. Longan fruit is rich in sugar, vitamins, and minerals, and has high nutritional and economic value, making it popular with consumers. At the same time, the longan tree has a beautiful shape and is evergreen all year round, also possessing certain ornamental value.

[0003] For a long time, longan propagation has mainly relied on seed propagation and grafting. While seed propagation is simple, the offspring have a long juvenile period, resulting in significant variation and making it difficult to maintain the traits of superior varieties; therefore, it is less commonly used in production. Grafting propagation can maintain the superior traits of the mother plant, with the scion having no juvenile period and bearing fruit early. It is currently a commonly used propagation method in longan production. However, grafting propagation requires high quality and compatibility of the rootstock and scion, as well as advanced operational techniques, resulting in lower propagation efficiency and greater dependence on seasonal and climatic conditions. Another method is air layering, also known as air layering, which is one of the traditional methods of longan propagation. This method can maintain the superior traits of the mother plant, but it is cumbersome, costly, and causes significant damage to the mother tree, which is detrimental to its continued growth and fruiting.

[0004] Propagation by cuttings is a highly efficient and simple asexual reproduction method with advantages such as high propagation coefficient, low cost, and simple operation, and is widely used in the propagation of various fruit trees. However, longan is a difficult-to-root species; its branches have difficulty rooting after conventional cutting treatment, resulting in a low survival rate. This is mainly because longan branches contain a relatively high amount of tannins and other substances that inhibit rooting, and the branches have a high degree of lignification, resulting in weak cell division and differentiation capabilities, making it difficult to form adventitious roots. Therefore, longan propagation by cuttings has always been a challenge in the field of longan propagation, restricting the rapid propagation and industrial development of superior longan varieties.

[0005] Current research on the propagation techniques of longan cuttings mainly focuses on the selection of propagation substrates, the application of rooting regulators, and the control of the propagation environment. For example, using a mixed substrate of perlite, vermiculite, and peat moss can improve the rooting rate of cuttings; treating branches with rooting regulators such as indolebutyric acid (IBA) and naphthaleneacetic acid (NAA) can promote the formation of adventitious roots; and controlling the temperature, humidity, and light conditions of the propagation environment can provide a suitable environment for rooting. However, although these methods can improve the rooting rate of longan cuttings to some extent, problems such as low rooting rate, long rooting time, and low transplant survival rate still exist, making it difficult to meet the needs of the longan industry's development. In addition, in vitro regeneration and genetic transformation technologies are important aspects of longan biotechnology research, and are of great significance for longan variety improvement, germplasm innovation, and gene function research. However, since the tissue culture and cutting propagation of longan are not yet perfect, it is difficult to obtain a large amount of sterile material, which seriously restricts the development of in vitro regeneration and genetic transformation technology of longan. Summary of the Invention

[0006] To address the aforementioned shortcomings in existing technologies, this invention provides a highly efficient method for inducing rooting in longan cuttings. This method, through measures such as selecting specific branches, optimizing girdling treatment, and choosing suitable substrates and culture conditions, can significantly improve the rooting rate and transplant survival rate of longan cuttings. This invention not only breaks down the barriers to successful longan cutting propagation but also lays the foundation for further research into in vitro regeneration and genetic transformation of longan.

[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: One objective of this invention is to provide a highly efficient method for inducing rooting in longan cuttings, comprising the following steps: (1) Select mature, perennial branches of longan; (2) Perform girdling treatment on the branches near the bud points; (3) Wrap the girdled area with a transparent plastic film containing moist substrate; (4) Cultivate the branches until they take root and then transplant them.

[0008] Preferably, the selection time for the perennial mature branches in step (1) is during the growth stage of longan shoots.

[0009] Preferably, the girdling treatment in step (2) involves girdling to remove a 2-4 mm wide section of bark and vascular bundle cambium, exposing the xylem.

[0010] Preferably, the moist substrate in step (3) is prepared by mixing field soil, nutrient soil, vermiculite and rooting powder in a volume ratio of 2~3:5~7:1~2:0.005~0.015.

[0011] Preferably, after step (3), the following steps are also included: topping the treated branch and removing excess tender stems from the treated branch.

[0012] Preferably, the cultivation period in step (4) is 60 to 80 days. When the roots emerge from the substrate and can be observed through the transparent plastic film, the branches are cut off and transplanted.

[0013] Preferably, the substrate used for transplanting in step (4) is prepared by mixing nutrient soil, perlite and vermiculite in a volume ratio of 4~6:0.5~1.5:1~3.

[0014] Preferably, when transplanting, retain 3-4 leaves on the branch, and cover the surface with a layer of perlite after transplanting to reduce the stress of sun exposure and high temperature. Observe the new buds and new leaves within 15-25 days to determine whether the transplant has survived.

[0015] The second objective of this invention is to provide the application of the aforementioned efficient method for inducing longan rooting in longan propagation and / or germplasm resource preservation.

[0016] The third objective of this invention is to provide the application of the aforementioned efficient method for inducing longan rooting in longan biological research.

[0017] Compared with the prior art, the present invention has the following beneficial effects: Currently, longan propagation mainly relies on grafting, with no breakthroughs in cutting propagation technology, as direct cuttings are extremely difficult to root. This invention efficiently induces rooting in longan branches (airborne rooting), which not only breaks down the barriers to longan cutting propagation but also lays the foundation for further research on in vitro regeneration and genetic transformation of longan. Attached Figure Description

[0018] Figure 1 The field operation procedure in Example 1 of this invention is as follows: (A) Ring barking treatment of mature perennial branches; (B) High pressure fixation of the ring barking treatment position with plastic film; (C) Approximately 60 days later, it can be observed through the plastic film that roots can emerge from the substrate.

[0019] Figure 2 The following is a diagram illustrating the entire growth and development process of aerial rooting propagation in Embodiment 1 of the present invention: (A) Callus tissue swells at the upper part of the girdled area; (B) Root morphology after removing the substrate, with roots growing from the girdled area; (C) Transplanting the treated branch into a flowerpot; (D) The state of new buds and leaves growing after transplanting the treated branch; (E) The morphology of the transplanted branch with normal subsequent growth; (F) The condition of the transplanted branch after one year of growth.

[0020] Figure 3The relevant situations in Comparative Examples 1-3 of this invention are as follows: (A) Aerial rooting results of 1-2 year old young branches; (B) Aerial rooting results of air layering propagation box treatment; (C) The upper side shows the results of random girdling treatment, and the lower side shows the results of girdling treatment near the bud point. The red dotted circle indicates the formation of callus tissue. Detailed Implementation

[0021] The following examples are used to illustrate the present invention, but are not intended to limit the scope of the invention. Any modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the invention are within the scope of the invention. The reagents, products, and instruments used in the following examples are all commercially available, and the methods used in the examples, unless otherwise specified, are consistent with conventionally used methods.

[0022] The longan variety used in this invention is Shixia Longan; the field soil was taken from the National Tropical Fruit Tree Germplasm Resource Nursery of the South Subtropical Crops Research Institute of the Chinese Academy of Tropical Agricultural Sciences, Mazhang District, Zhanjiang City, Guangdong Province. The basic physicochemical indicators of the soil were tuff-brick lateritic soil (pH 4.82, organic matter 2.27%, total nitrogen 1.20 g / kg, available phosphorus 38.89 mg / kg, available potassium 336.67 mg / kg); the nutrient soil was PINDSTRUP nutrient soil, purchased from Shanghai Xiaoyun Horticulture Co., Ltd., product number LV0145; the vermiculite with basic parameters of 20-40 mesh was purchased from Qingdao Lvsheng Biotechnology Co., Ltd., product number LS-ZS-24544; the perlite with basic parameters of 4-8 mm was purchased from Xiangtan Zhiqi Agricultural Technology Co., Ltd.; the rooting powder was plant rooting powder, the category of "bursting rooting plants rapidly recover vitality", purchased from Shanghai Zhilv Biotechnology Co., Ltd.; the basic parameters of the transparent plastic film were 60 100 cm long, 0.3 mm thick, purchased from Disai Plastics Packaging Company; the basic parameters of the black high-pressure planting box are 12 cm in length and 12 cm in width. 13 cm in diameter and 11 cm in diameter, purchased from Shandong Huayan Plastics Co., Ltd.

[0023] The technical solution of the present invention will be further described in detail below with reference to the embodiments.

[0024] Example 1 (1) Prepare the substrate by mixing field soil, nutrient soil, vermiculite and rooting powder in a volume ratio of 2.5:6:1.5:0.01. (2) The best time for treatment is during the season when longan sprouts new shoots. Select mature branches of longan trees that are healthy and mature for many years. Select the girdling site near the bud point of the branch. Use a girdling knife to remove the bark and vascular bundle cambium with a width of 2-4 mm, exposing the xylem. (3) Use a transparent plastic film to hold the moist substrate (moisture content 40-50%), fix the container holding the substrate, and keep the girdling wound tightly wrapped by the substrate; (4) Remove the top of the treated branch and remove any excess tender stems from the treated branch; (5) The cycle is about 60 days. When the roots emerge from the substrate and can be observed through the plastic film, the branches can be cut and transplanted. (6) Transplant into a planting pot. Mix nutrient soil, perlite and vermiculite in a volume ratio of 5:1:2 to prepare a potting substrate. Only retain 3-4 leaves on the branches. After transplanting, cover the surface with a layer of perlite to reduce the stress of sunlight and high temperature. New buds and new leaves can be observed within 20 days. Based on this, judge whether the transplant has survived.

[0025] Comparative Example 1 (1) Prepare the substrate by mixing field soil, nutrient soil, vermiculite and rooting powder in a volume ratio of 2.5:6:1.5:0.01. (2) The best time for treatment is during the season when longan sprouts new shoots. Select 1-2 year old tender branches from healthy longan trees. Select the girdling site near the bud point of the branch. Use a girdling knife to remove the bark and vascular bundle cambium with a width of 2-4 mm, exposing the xylem. (3) Use a transparent plastic film to hold the moist substrate, fix the container holding the substrate, and keep the girdling wound tightly wrapped by the substrate; (4) Remove the top of the treated branch and remove any excess tender stems from the treated branch; (5) The cycle is about 60 days. When the roots emerge from the substrate and can be observed through the plastic film, the branches can be cut and transplanted. (6) Transplant into a planting pot. Mix nutrient soil, perlite and vermiculite in a volume ratio of 5:1:2 to prepare a potting substrate. Only retain 3-4 leaves on the branches. After transplanting, cover the surface with a layer of perlite to reduce the stress of sunlight and high temperature. New buds and new leaves can be observed within 20 days. Based on this, judge whether the transplant has survived.

[0026] Comparative Example 2 (1) Prepare the substrate by mixing field soil, nutrient soil, vermiculite and rooting powder in a volume ratio of 2.5:6:1.5:0.01. (2) The best time for treatment is during the season when longan sprouts new shoots. Select mature branches of longan trees that are healthy and mature for many years. Select the girdling site near the bud point of the branch. Use a girdling knife to remove the bark and vascular bundle cambium with a width of 2-4 mm, exposing the xylem. (3) Use a black high-pressure propagation box to hold moist substrate, fix the container holding the substrate, and keep the girdling wound tightly wrapped by the substrate; (4) Remove the top of the treated branch and remove any excess tender stems from the treated branch; (5) The cycle is about 60 days, then the branches are cut and transplanted; (6) Transplant into a planting pot. Mix nutrient soil, perlite and vermiculite in a volume ratio of 5:1:2 to prepare a potting substrate. Only retain 3-4 leaves on the branches. After transplanting, cover the surface with a layer of perlite to reduce the stress of sunlight and high temperature. New buds and new leaves can be observed within 20 days. Based on this, judge whether the transplant has survived.

[0027] Comparative Example 3 (1) Prepare the substrate by mixing field soil, nutrient soil, vermiculite and rooting powder in a volume ratio of 2.5:6:1.5:0.01. (2) The best time for treatment is during the season when longan sprouts new shoots. Select mature branches of longan trees that are healthy and mature for many years. The girdling site is random. Use a girdling knife to remove the bark and vascular bundle cambium with a width of 2-4 mm, exposing the xylem. (3) Use a transparent plastic film to hold the moist substrate, fix the container holding the substrate, and keep the girdling wound tightly wrapped by the substrate; (4) Remove the top of the treated branch and remove any excess tender stems from the treated branch; (5) The cycle is about 60 days. When the roots emerge from the substrate and can be observed through the plastic film, the branches can be cut and transplanted. (6) Transplant into a planting pot. Mix nutrient soil, perlite and vermiculite in a volume ratio of 5:1:2 to prepare a potting substrate. Only retain 3-4 leaves on the branches. After transplanting, cover the surface with a layer of perlite to reduce the stress of sunlight and high temperature. New buds and new leaves can be observed within 20 days. Based on this, judge whether the transplant has survived.

[0028] The experimental data for Example 1 and Comparative Examples 1-3 are shown in Table 1 below.

[0029] Table 1 Statistical Data Details

[0030] The subsequent survival status of each treatment group is as follows: Example 1: Thirteen branches had roots before being cut, while two branches only had callus tissue at the time of cutting but rooted after transplanting. Currently, all 15 materials have survived and are growing normally.

[0031] Comparative Example 1:1 The branches had roots before being cut and could sprout new buds, but their subsequent growth was insufficient, and no new leaves grew. The root system was not dead at the moment, but the growth was stagnant.

[0032] Comparative Example 2: One branch had roots before being cut off, but failed to sprout new buds after transplanting, and subsequently withered and died. The other two branches only had callus tissue at the time of cutting off, survived after transplanting, and grew normally.

[0033] Comparative Example 3: Two branches rooted before being cut and sprouted new buds and leaves after transplanting, showing normal growth.

[0034] The results are analyzed as follows: (1) Regarding Comparative Example 1, although the 1-2 year old tender branches can still maintain a relatively high callus formation rate after treatment, the subsequent rooting rate is extremely low, and the growth is significantly insufficient after transplanting. It is speculated that the tender branches have less stored nutrients.

[0035] (2) Regarding Comparative Example 2, air layering propagation boxes are commonly used tools for the air-rooting propagation of woody plants. However, considering that the growing area of ​​longan is located in the hot and humid subtropical and tropical regions, the fixation of air layering propagation boxes is significantly weaker than that of plastic film when there is sufficient rainfall. This will lead to two problems: First, the substrate and the girdled part are not tightly attached, which seriously affects the subsequent rooting induction. Second, the slippery surface will cause the air layering propagation box to move, which will affect the static growth environment of the girdled part (movement up and down, ants entering, etc.) and may also cause water loss in the substrate.

[0036] (3) For Comparative Example 3, narrowing the interval and focusing on the position near the bud point for girdling can guarantee the formation rate of callus tissue. In the comparative example, random girdling position will reduce the formation rate of callus tissue, thus affecting the subsequent rooting frequency.

[0037] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A highly efficient method for inducing rooting in longan cuttings, characterized in that, Includes the following steps: (1) Select mature, perennial branches of longan; (2) Perform girdling treatment on the branches near the bud points; (3) Wrap the girdled area with a transparent plastic film containing moist substrate; (4) Cultivate the branches until they take root and then transplant them.

2. The efficient method for inducing longan rooting according to claim 1, characterized in that, The selection time for the perennial mature branches mentioned in step (1) is during the growth stage of the new shoots of longan.

3. The efficient method for inducing longan rooting according to claim 1, characterized in that, The girdling treatment described in step (2) involves girdling to remove a 2-4 mm wide section of bark and vascular bundle cambium, exposing the xylem.

4. The efficient method for inducing longan rooting according to claim 1, characterized in that, The moist substrate mentioned in step (3) is prepared by mixing field soil, nutrient soil, vermiculite and rooting powder in a volume ratio of 2~3:5~7:1~2:0.005~0.

015.

5. The efficient method for inducing longan rooting according to claim 1, characterized in that, The steps following step (3) include: removing the top of the treated branch and removing excess tender stems from the treated branch.

6. The efficient method for inducing longan rooting according to claim 1, characterized in that, The cultivation period described in step (4) is 60 to 80 days. When the roots emerge from the substrate and can be observed through the transparent plastic film, the branches are cut off and transplanted.

7. The efficient method for inducing longan rooting according to claim 1, characterized in that, The substrate used for transplanting in step (4) is prepared by mixing nutrient soil, perlite and vermiculite in a volume ratio of 4~6:0.5~1.5:1~3.

8. The efficient method for inducing longan rooting according to claim 7, characterized in that, When transplanting, retain 3-4 leaves on the branch. After transplanting, cover the surface with a layer of perlite to reduce the stress of sun exposure and high temperature. Observe the new buds and new leaves within 15-25 days to determine whether the transplant has survived.

9. The application of the efficient method for inducing longan rooting as described in any one of claims 1 to 8 in longan propagation and / or germplasm resource preservation.

10. The application of the efficient rooting induction method for longan as described in any one of claims 1 to 8 in longan biological research.

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