A method for overcoming the obstacles of distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins

Abstract

The present invention relates to a method for overcoming obstacles to distant hybridization between crape myrtle and loosestrife using gibberellins. The method comprises the following steps: emasculation: before the crape myrtle flowers fully open and shed pollen, the stamens on the flowers are completely removed with tweezers and covered with a sulfuric acid paper bag for isolation; mist spraying a gibberellin solution: evenly spraying the gibberellin solution on the stigma of the crape myrtle pistil; and pollination: on sunny and windless days, using a cotton swab to dip loosestrife pollen, applying the pollen to the stigma of the crape myrtle pistil treated with the gibberellin solution, and promptly bagging and marking the flowers after pollination. The technical problem to be solved by the present invention is to promote fertilization and fruit setting in distant hybridization between crape myrtle and loosestrife by mist spraying the stigma with gibberellins before pollination, thereby overcoming the obstacles to distant hybridization.

Description

Technical Field

[0001] The invention belongs to the technical field of plant hybridization, and particularly relates to a method for overcoming the distant hybridization obstacle between crape myrtle and loosestrife by utilizing gibberellins. Background Art

[0002] Crape myrtle Lagerstroemia indica ) is a plant of the genus Lagerstroemia in the Lythraceae family, native to China. It is a traditional famous flower in my country and one of the most popular summer flowering tree species in garden applications. It is widely cultivated and used around the world and has extremely high economic and cultural value. Lythrum salicaria Lythrum spp., a member of the Lythrum genus of the Lythraceae family, combines ornamental value with ecological adaptability, playing a crucial role in aquatic landscape design. Lythrum spp., distributed as far north as Heilongjiang Province, China, is known for its strong cold tolerance. As a closely related genus of the genus Lagerstroemia, Lythrum spp. has the potential to serve as an important germplasm resource for improving the cold tolerance of Lagerstroemia.

[0003] Distant hybridization refers to the crossbreeding of species, genera, or even more distantly related plant groups in plant taxonomy. In the genetic improvement of ornamental plants, distant hybridization has been widely validated as an effective method for introducing genetic variation. However, due to severe reproductive barriers between distantly related species, successful hybridization often remains difficult. Sexual barriers in distant hybridization can be categorized as pre- and post-fertilization barriers. Pre-fertilization barriers refer to the inability to complete fertilization and develop a zygote. Post-fertilization barriers refer to hybrid collapse caused by incoordination between the development of the hybrid embryo and endosperm tissue, leading to embryo degradation or abortion, or hybrid sterility.

[0004] Distant hybridization between crape myrtle and loosestrife suffers from severe hybridization barriers, manifested in large numbers of flowers and fruits dropping after artificial pollination. Currently, no technology exists to overcome these barriers. Summary of the Invention

[0005] In view of this, the main purpose of the present invention is to provide a method for overcoming the barriers to distant hybridization between Lagerstroemia indica and Lythrum salicaria by utilizing gibberellins. The technical problem to be solved is to promote the fertilization and fruit setting of distant hybridization between Lagerstroemia indica and Lythrum salicaria by spraying gibberellins on the stigmas before pollination, thereby overcoming the barriers to distant hybridization.

[0006] The purpose of the present invention and the technical problem solved are achieved by adopting the following technical solutions. The present invention proposes a method for overcoming the barrier of distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, comprising the following steps:

[0007] 1) Emasculation: Before the crape myrtle flowers fully open and shed pollen, use tweezers to remove the stamens from the flowers and place them in a sulfuric acid paper bag for isolation;

[0008] 2) Mist spraying gibberellin solution: spray the gibberellin solution evenly on the stigma of the pistil of the crape myrtle;

[0009] 3) Pollination: On a sunny day without strong winds, use a cotton swab to dip the pollen of Lythrum salicaria and apply it to the stigma of the crape myrtle treated with gibberellin solution. After pollination, bag the flowers and mark them in time.

[0010] The objectives and technical problems solved by the present invention can be further achieved by adopting the following technical measures.

[0011] Preferably, in the aforementioned method of overcoming the barrier to distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, in step 1), the time for emasculation is 4:00 to 6:00 in the morning on a clear and windless day.

[0012] Preferably, in the aforementioned method of overcoming the barrier of distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, in step 2), the variety of Lagerstroemia indica is 'Pink Crystal' or 'Multi-Flower Purple'.

[0013] Preferably, in the aforementioned method of using gibberellins to overcome the barrier of distant hybridization between Lagerstroemia indica and Lythrum salicaria, in step 2), the concentration of the gibberellins solution is 150-250 mg·L -1 .

[0014] Preferably, in the aforementioned method of overcoming the barrier to distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, in step 2), the Lagerstroemia indica variety is 'Pink Crystal', and 250 mg·L of gibberellins is evenly sprayed on the pistil stigma of 'Pink Crystal' after emasculation and before pollination. -1 Gibberellin solution.

[0015] Preferably, in the aforementioned method of overcoming the barrier to distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, in step 2), the Lagerstroemia indica variety is 'Duohua Zi', and 200 mg·L gibberellins are evenly sprayed on the pistil stigma of 'Duohua Zi' after emasculation and before pollination. -1 Gibberellin solution.

[0016] Preferably, in the aforementioned method of using gibberellins to overcome the barrier to distant hybridization between crape myrtle and Lythrum salicaria, in step 2), the crape myrtle variety is 'Pink Crystal', and 200 mg·L gibberellins are evenly sprayed on the pistil stigma of 'Duohua Zi' after emasculation and before pollination. -1 Gibberellin solution.

[0017] Preferably, in the aforementioned method of overcoming the barrier to distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, in step 2), the Lagerstroemia indica variety is 'Duohua Zi', and 200 mg·L gibberellins are evenly sprayed on the pistil stigma of 'Duohua Zi' after emasculation and before pollination. -1 Gibberellin solution.

[0018] Preferably, in the aforementioned method of overcoming the barrier to distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, in step 3), the pollination time is between 9:00 and 10:00 in the morning under clear and windless weather.

[0019] Preferably, in the aforementioned method of overcoming the barrier to distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, in step 1), the tweezers are disinfected with a 75% (v / v) alcohol solution.

[0020] Compared with the prior art, the method of overcoming the distant hybridization barrier between Lagerstroemia indica and Lythrum salicaria using gibberellins described in the present invention has the following beneficial effects:

[0021] 1. The present invention can overcome the distant hybridization barrier between Lagerstroemia indica and Lythrum salicaria conveniently and at low cost. The present invention simply and evenly sprays 150-250 mg·L of the Lagerstroemia indica pistil stigma after emasculation and before pollination. -1 Gibberellic acid solution can promote distant hybridization between Lagerstroemia indica and Lythrum salicaria and improve the degree of affinity.

[0022] 2. The present invention provides a practical technical means for obtaining hybrid offspring of crape myrtle and Lythrum salicaria. By spraying a gibberellin solution on the stigma of crape myrtle pistils, the fruit setting rate is increased. On this basis, hybrid offspring plants can be obtained through embryo culture or seed sowing.

[0023] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The photos of crape myrtle and loosestrife of the embodiment of the present invention, wherein A: crape myrtle 'Duohua Zi'; B: crape myrtle 'Rose Quartz'; C: loosestrife;

[0025] Figure 2 This is a diagram showing the pollen tube growth of 'Pink Crystal' × Lythrum salicaria in an embodiment of the present invention; wherein, a: OU: ovule; the arrow points to the pollen tube. b: Figure 2 Figures A to L show the growth of pollen tubes 1, 2, 4, 8, 12, 24, 48, and 72 hours after pollination; Figures K and L show the growth of papillary cells, style, and ovary 72 hours after pollination;

[0026] Figure 3 This is a diagram showing the pollen tube growth of 'Purple Flower' × Lythrum salicaria of the present invention; a: OU: ovule; arrows point to pollen tubes. b: Figure 2Figures A to L show the growth of pollen tubes 1, 2, 4, 8, 12, 24, 48, and 72 hours after pollination; Figures K and L show the growth of papillary cells, style, and ovary 72 hours after pollination;

[0027] Figure 4 The flower survival of Rose Quartz × Lythrum salicaria hybrid 1 to 3 days after pollination under different concentrations of GA3 treatment according to the present invention; a: T1 to T3: 150, 200, and 250 mg·L⁻¹ GA3; CK: clean water;

[0028] Figure 5 The fruit retention of Rose Quartz × Lythrum salicaria hybrid 4 to 31 days after pollination under different concentrations of GA3 treatment according to the embodiment of the present invention; a: T1 to T3: 150, 200, 250 mg·L⁻¹ GA3; CK: clean water;

[0029] Figure 6 The flower survival rate of 'Purple Flower' × Lythrum salicaria hybrid 1 to 3 days after pollination under the same concentration of GA3 treatment in the examples of the present invention; a: T1 to T3: 150, 200, 250 mg·L⁻¹ GA3; CK: clean water;

[0030] Figure 7 The fruit retention of 'Purple Flower' × Lythrum salicaria hybrid 4 to 31 days after pollination under different concentrations of GA3 treatment according to the embodiment of the present invention; a: T1 to T3: 150, 200, 250 mg·L⁻¹ GA3; CK: clean water;

[0031] Figure 8 Figure 1 is a microscopic observation of paraffin sections of self-pollinated embryos from the present invention; Note a: The red arrows indicate zygotes; a and b are zygotes 4 and 6 days after pollination, respectively; c and d are multicellular proembryos 4 and 6 days after pollination, respectively; e is a globular embryo 16 days after pollination; f is a torpedo-shaped embryo 14 days after pollination; g is a late cotyledonary stage 18 days after pollination; and h is a mature embryo 35 days after pollination.

[0032] Figure 9 Figure 1 shows microscopic observations of paraffin sections of embryonic development from a 'Rose Quartz' × Lythrum salicaria hybrid according to an embodiment of the present invention; Note a: a and b are multicellular proembryos 4 and 6 days after pollination, respectively; c, d, and e are deformed embryos 8, 14, and 16 days after pollination, respectively, showing deformed and empty embryo sacs; f is a mature embryo 30 days after pollination;

[0033] Figure 10Figures showing embryo culture of selfed and hybrid fruits of Rose Crystal × Lythrum salicaria from the present invention. Note: A: Fruit treated with 250 mg·L⁻¹ GA3 solution 30 days after hybrid pollination; B and C: Germination of hybrid and selfed embryos, respectively, 7 days after inoculation; D: Fruit of Rose Crystal 30 days after self-pollination; E and F: Rose Crystal selfed embryos with abundant roots 36 days after inoculation.

[0034] Figure 11 This is a diagram of the 'Rose Quartz' seedlings and the F1 generation of the hybrid of 'Rose Quartz' × Lythrum salicaria according to the embodiment of the present invention; Note a: (1): A to D are the F1 generation of the hybrid of 'Rose Quartz' × Lythrum salicaria to be identified; (2): A and B are 'Rose Quartz' seedlings. DETAILED DESCRIPTION

[0035] To further illustrate the technical means and efficacy employed by the present invention to achieve the intended purpose of the invention, the following, in conjunction with preferred embodiments, describes in detail the specific implementation, structure, features, and efficacy of a method for overcoming the barrier to distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0036] Unless otherwise specified, the materials and reagents mentioned below are all commercially available products familiar to those skilled in the art; unless otherwise specified, the methods described are all methods well known in the art. Unless otherwise defined, technical or scientific terms used should have the same meanings as those of ordinary skill in the art. Where specific experimental procedures or conditions are not specified below, the procedures or conditions described in the literature in this field can be followed.

[0037] Some embodiments of the present invention provide a method for overcoming the barrier of distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, comprising the following steps:

[0038] 1) Emasculation: Between 4:00 and 6:00 in the morning on a clear, windless day, before the flowers of the crape myrtle fully open and shed pollen, use tweezers to remove the stamens from the flowers and cover them with a sulfuric acid paper bag to isolate them. When removing the stamens, you need to be careful not to damage the pistils. Effect: Emasculation and bagging can prevent hybridization from being interfered with by foreign pollen and can protect the pistils.

[0039] 2) Mist spraying gibberellin solution: spray the gibberellin solution evenly on the stigma of the pistil of the crape myrtle;

[0040] 3) Pollination: On a clear, windless day, use a cotton swab to dip Lythrum salicaria pollen and gently apply it to the stigma of the crape myrtle treated with the gibberellin solution. After pollination, bag the pistil and mark it. There is no limit to the amount of pollen applied, as long as the stigma is visible to the naked eye.

[0041] In some optional embodiments, in step 1), the time for emasculation is 4:00-6:00 in the morning under clear and windless weather. Too early (e.g., earlier than 4:00 in the morning) or too late (e.g., later than 6:00 in the morning) is not conducive to the smooth progress of the hybridization pollination experiment.

[0042] In some optional embodiments, in step 2), the crape myrtle variety is 'Pink Crystal' or 'Multi-Flower Purple'. The crape myrtle varieties 'Pink Crystal' and 'Multi-Flower Purple' have bright flower colors and good growth conditions, and are suitable as hybrid parents.

[0043] In some optional embodiments, in step 2), the concentration of the gibberellin solution is 150-250 mg·L -1 150-250mg·L -1 Gibberellic acid solution is a suitable hormone to promote fertilization and fruit setting of hybrid combinations ('Pink Crystal' and Lythrum salicaria), and the concentration is less than 150 mg·L -1 or higher than 250 mg·L -1 , the fruit setting rate will decrease.

[0044] In some optional embodiments, in step 2), the variety of crape myrtle is 'Rose Crystal', and for the hybrid combination 'Rose Crystal' × Lythrum salicaria, 200 mg·L is evenly sprayed on the stigma of the 'Rose Crystal' pistil after emasculation and before pollination. -1 or 250 mg·L -1 According to the experiments in the specific examples, 250 mg·L -1 The gibberellin solution can more effectively promote the fertilization and fruit setting of the hybrid combination 'Rose Quartz'× Lythrum salicaria.

[0045] In some optional embodiments, in step 2), the variety of crape myrtle is 'Pink Crystal', and for the hybrid combination 'Duohua Purple' × Lythrum salicaria, 200 mg·L is evenly sprayed on the pistil stigma of 'Duohua Purple' after emasculation and before pollination. -1 or 250 mg·L -1 According to the experiments in the specific examples, 200 mg·L -1 The gibberellin solution can more effectively promote the fertilization and fruit setting of the hybrid combination 'Duohua Zi'× Lythrum salicaria.

[0046] In some optional embodiments, based on hybridization research, in step 3), the pollination time can be set to 9:00-10:00 a.m. on a clear and windless day. This setting is conducive to distant hybridization between Lagerstroemia and Henna.

[0047] In some optional embodiments, the method specifically includes the following steps:

[0048] 1) Emasculation is generally performed between 4:00 and 6:00 AM on clear, windless days. When the buds have opened but the petals have not yet expanded, disinfect the tweezers with 75% (v / v) alcohol. Then, use the sterilized tweezers to remove all stamens, ensuring that the pistils are not damaged during the emasculation process. After emasculation, bag the emasculated inflorescence with a sulfuric acid paper bag. Avoid squeezing the inflorescence during bagging, seal the bag with a paper clip, and mark the bag with parental information and the number of emasculated flowers. "Buds have opened but petals have not yet expanded" is visually determined when the buds are loose and the petals are curled up in the bud and have not yet expanded.

[0049] 2) The gibberellin solution should be sprayed before pollination. It should be evenly sprayed and ensure that branches and leaves in other parts of the body are not affected by exogenous hormones. For the hybrid combination 'Pink Crystal' × Lythrum salicaria, 250 mg·L -1 Gibberellic acid solution, and the hybrid combination 'Duohua Zi'× Lythrum salicaria used 200 mg·L -1 Gibberellic acid solution; this setting can promote the fertilization and fruit setting of the hybrid female plant.

[0050] 3) Pollination is generally carried out between 8:00 AM and 10:00 AM on clear, windless days. When the flowers are in full bloom and the stigmas secrete a large amount of mucus, spray the stigmas with a gibberellin solution and then pollinate. Use a cotton swab to apply pollen to the stigma of the Lythrum salicaria pistil. After pollination, bag the flowers and mark them.

[0051] In the above technical solution, the present invention can significantly improve the phenomenon of flower and fruit drop by spraying gibberellin solution on the stigma of emasculated crape myrtle and then pollinating, thereby overcoming the obstacle of distant hybridization to a certain extent.

[0052] The present invention will be further described below with reference to specific embodiments, but this should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made to the present invention by those skilled in the art based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0053] Example 1

[0054] This embodiment provides a method for overcoming the barrier of distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, comprising the following steps:

[0055] 1) Emasculation: Perform emasculation between 4:30 AM and 6:00 AM on clear, windless days for one and a half hours. Select the 'Pink Quartz' crape myrtle variety. The buds should be open, the buds loose, and the petals curled up within the buds, but not yet unfolded. Remove all stamens using tweezers disinfected with 75% (v / v) alcohol, ensuring that the pistils are not damaged during the emasculation process. After emasculation, bag the emasculated inflorescence in a sulfuric acid paper bag approximately 26 x 17 cm. Avoid squeezing the inflorescence during bagging. Seal the bag with a paper clip and write the parentage information and the number of emasculated flowers in pencil on the surface of the bag.

[0056] 2) Mist spraying gibberellin solution: 250 mg·L -1 The gibberellin solution was evenly sprayed on the stigma of the pistil of Lagerstroemia indica ‘Pink Crystal’;

[0057] 3) Pollination: On a sunny day without strong winds, use a cotton swab to dip the pollen of Lythrum salicaria and gently apply it to the stigma of the crape myrtle treated with gibberellin solution. After pollination, bag the flowers and mark them in time.

[0058] 100 flowers were pollinated, and the experiment was repeated three times. Flower drop was recorded daily for 1-3 days after pollination, and fruit drop was recorded daily for 4-7 days after pollination. After one week, the data were recorded every three days until one month after pollination. The flower and fruit drop data are shown in Table 1.

[0059] Example 2

[0060] The difference between this embodiment and embodiment 1 is that the concentration of the gibberellin solution in this embodiment is 200 mg·L -1 The remaining steps and parameters are the same as those in Example 1. The flower and fruit drop conditions are shown in Table 1.

[0061] Example 3

[0062] The difference between this embodiment and embodiment 1 is that the concentration of the gibberellin solution in this embodiment is 150 mg·L -1 The remaining steps and parameters are the same as those in Example 1. The flower and fruit drop conditions are shown in Table 1.

[0063] Example 4

[0064] The difference between this embodiment and embodiment 1 is that the crape myrtle variety in this embodiment is 'Duohua Zi'; the remaining steps and parameters are the same as those in embodiment 1. The flower and fruit drop conditions are shown in Table 2.

[0065] Example 5

[0066] The difference between this embodiment and embodiment 4 is that the concentration of the gibberellin solution in this embodiment is 200 mg·L -1 The remaining steps and parameters are the same as those in Example 4. The flower and fruit drop conditions are shown in Table 2.

[0067] Example 6

[0068] The difference between this embodiment and embodiment 4 is that the concentration of the gibberellin solution in this embodiment is 150 mg·L -1 The remaining steps and parameters are the same as those in Example 4. The flower and fruit drop conditions are shown in Table 2.

[0069] Comparative Example 1

[0070] The difference between this comparative example and Example 1 is that the concentration of the gibberellin solution in this comparative example is 0. The remaining steps and parameters are the same as those in Example 1. The flower and fruit drop conditions are shown in Table 1.

[0071] Comparative Example 2

[0072] The difference between this comparative example and Example 1 is that this comparative example uses 6-BA solution with a concentration of 20 mg·L -1 The remaining steps and parameters are the same as those in Example 1. The flower and fruit drop conditions are shown in Table 1.

[0073] Comparative Example 3

[0074] The difference between this comparative example and Example 1 is that this comparative example uses 6-BA solution with a concentration of 30 mg·L -1 The remaining steps and parameters are the same as those in Example 1. The flower and fruit drop conditions are shown in Table 1.

[0075] Comparative Example 4

[0076] The difference between this comparative example and Example 1 is that this comparative example uses 6-BA solution with a concentration of 40 mg·L -1 The remaining steps and parameters are the same as those in Example 1. The flower and fruit drop conditions are shown in Table 1.

[0077] Comparative Example 5

[0078] The difference between this comparative example and Example 4 is that the concentration of the gibberellin solution in this comparative example is 0. The remaining steps and parameters are the same as those in Example 4. The flower and fruit drop conditions are shown in Table 2.

[0079] Comparative Example 6

[0080] The difference between this comparative example and Example 4 is that this comparative example uses 6-BA solution with a concentration of 20 mg·L -1 The remaining steps and parameters are the same as those in Example 4. The flower and fruit drop conditions are shown in Table 2.

[0081] Comparative Example 7

[0082] The difference between this comparative example and Example 4 is that this comparative example uses 6-BA solution with a concentration of 30 mg·L-1 The remaining steps and parameters are the same as those in Example 4. The flower and fruit drop conditions are shown in Table 2.

[0083] Comparative Example 8

[0084] The difference between this comparative example and Example 4 is that this comparative example uses 6-BA solution with a concentration of 40 mg·L -1 The remaining steps and parameters are the same as those in Example 4. The flower and fruit drop conditions are shown in Table 2.

[0085] Table 1 Statistics on the average number of flowers and fruits remaining in Lagerstroemia indica ‘Pink Crystal’ under different treatments

[0086]

[0087] Table 2 Statistics on the average number of flowers and fruits remaining in Lagerstroemia indica ‘Duohuazi’ under different treatments

[0088]

[0089] By comparing the examples with the comparative examples, it can be found that in comparative examples 1 and 4, the concentration of the gibberellin solution was 0, and the flowers and ovaries of the crape myrtle varieties 'Pink Crystal' and 'Multi-Flower Purple' fell off 3 and 5 days after pollination, respectively. In Examples 1 to 6, by spraying 150 to 250 mg·L -1 The gibberellins can improve the phenomenon of flower and fruit drop to varying degrees. -1 The improvement effect of gibberellin solution was relatively the best, and the fruit setting rate could reach 78.33% 31 days after pollination. For 'Duohua Zi', 200 mg·L -1 The improvement effect of gibberellin solution is relatively the best, and the fruit setting rate can reach 59.33% 31 days after pollination.

[0090] Specific application example 1

[0091] From July to August 2024, artificial assisted pollination was carried out on the distant hybridization of Lagerstroemia indica and Lythrum salicaria at Sanqing Garden of Beijing Forestry University. Figure 1 shown.

[0092] By observing the pollen tubes of flowers that were not pollinated by spraying GA3 solution, it was found that only a few pollen tubes entered the ovary or ovules, accompanied by a large number of flowers and fruits falling. Figure 2 、 3 As shown. Figure 2 、 Figure 3It can be seen that 72 hours after pollination, a large amount of callus was still accumulated at the junction of the papillary cells and the style and even at the upper end of the style, and very few pollen tubes were observed in the ovary.

[0093] Choose clear, windless weather for artificial pollination. Between 4:00 and 6:00 AM, when the buds have opened but the petals have not yet expanded, emasculate the flowers using tweezers disinfected with 75% (v / v) alcohol solution and cover with a sulfuric acid paper bag to prevent contamination by foreign pollen.

[0094] Between 8:00 and 10:00 AM, the flowers are in full bloom, and their stigmas secrete a large amount of mucus. Remove the sulfuric acid paper bag and spray the stigmas of the 'Rose Quartz' and 'Multi-Flower Purple' varieties with the GA3 solution. Then, use a cotton swab to dip pollen and gently apply it to the stigmas of the 'Rose Quartz' and 'Multi-Flower Purple' varieties. After pollination, bag the flowers and mark them.

[0095] For the hybrid combination of 'Rose Quartz' and Lythrum salicaria, all flowers sprayed with water (CK group) fell off on the third day after pollination ( Figure 4 ). Compared with 150 and 200 mg·L -1 GA3 solution, 250 mg·L -1 The GA3 solution was relatively suitable for flower and fruit preservation. Three days after pollination, the flower retention rate was 96.67% ( Figure 4 ), the fruit setting rate reached 78.33% 31 days after pollination ( Figure 5 ).

[0096] For the hybrid combination of 'Duohua Zi' and Lythrum salicaria, all the flowers sprayed with water (CK group) fell off on the 5th day after pollination ( Figure 6 ). Compared with 150 and 250 mg·L -1 GA3 solution, 200 mg·L -1 The GA3 solution has a relatively suitable effect in flower and fruit preservation. Three days after pollination, the flower retention rate was 97.43% ( Figure 6 ), the fruit setting rate reached 59.33% 31 days after pollination ( Figure 7 ).

[0097] Specific application example 2

[0098] In the hybrid combination of 'Pink Crystal' and Lythrum salicaria, 250 mg·L -1 The solution was sprayed on the pistil stigma to promote fertilization and fruit setting. By comparing the fruit development status of the self-pollinated 'Pink Crystal' and the hybrid of 'Pink Crystal'× Lythrum salicaria, 250mg·L -1 The solution can promote the development of hybrid fruits to a certain extent and overcome the hybridization barrier between 'Pink Crystal' and Lythrum salicaria ( Figure 8 、 9 ).

[0099] The development process of the self-pollinated fruit of 'Pink Crystal' is that the zygote begins to divide 2 to 4 days after pollination ( Figure 8 .a), Multicellular proembryo appears 4 or 6 days after pollination ( Figure 8 .c, d), 10 days after pollination, the embryos entered the globular embryo stage ( Figure 8 .e), because embryonic development in the same ovary may not be synchronous, torpedo-shaped embryos can be observed as early as 14 days after pollination ( Figure 8 .f). Therefore, 10 to 16 days after pollination, the embryo may be in the process of globular embryo, torpedo-shaped embryo, or globular embryo to torpedo-shaped embryo transformation. 18 days after pollination, the embryo can be observed in the cotyledon stage and has developed to a relatively mature stage ( Figure 8 .g). ​​Mature embryos can be observed 30 days after pollination ( Figure 8 .h).

[0100] In contrast to the self-fertilized embryos, multicellular proembryos were observed in the distant hybrid fruits of 'Rose Quartz' × Lythrum salicaria 4 and 6 days after pollination (see Figure 9 .a、 Figure 9 .b), but 8, 14, and 16 days after pollination (see Figure 9 .c, Figure 9 .d, Figure 9 .e), further development of multicellular proembryo was not observed, instead the embryo sac was deformed and empty. However, 30 days after cross-pollination, mature embryos were observed (see Figure 9 .f). This shows that although most of the sliced ​​tissues may begin to abort 6 days after pollination, due to the spraying of 250mg·L -1 GA3 solution, there are a few embryos that can develop normally to maturity.

[0101] Specific application example 3

[0102] 250mg·L -1 Embryo culture was performed on the fruits of the self-pollination and hybridization of 'Pink Crystal' × Lythrum salicaria 30-35 days after pollination by mist spraying with GA3 solution (see Figure 10 .A. Figure 10 .D). Seven days after inoculation, both hybrid and self-pollinated embryos developed young roots and cotyledons (see Figure 10 .B. Figure 10 .C). Due to the contamination of the culture medium, when the roots grew to about 1 cm, the self-pollinated seedlings and hybrid seedlings were transplanted into square pots for maintenance. A total of 4 hybrid F1 plants to be identified were obtained (see Figure 11 ). This shows that 250mg·L -1 GA3 solution not only has a certain fruit-preserving effect, but also can promote the growth and development of embryos.

[0103] In the description of the present invention, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some embodiments, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0104] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0105] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

[0106] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiment based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for overcoming the barrier of distant hybridization between Lagerstroemia indica and Lythrum salicaria using gibberellins, characterized in that: The following steps are involved: 1) Emasculation: Before the crape myrtle flowers fully open and shed pollen, use tweezers to remove the stamens from the flowers and place them in a sulfuric acid paper bag for isolation; 2) Mist spraying of gibberellin solution: Spray the gibberellin solution evenly on the stigma of the pistil of crape myrtle (the crape myrtle variety should be 'Pink Crystal' or 'Duohua Zi'). The concentration of the gibberellin solution should be 150-250 mg·L -1 ; 3) Pollination: On a sunny day without strong winds, use a cotton swab to dip the pollen of Lythrum salicaria and apply it to the stigma of the crape myrtle treated with gibberellin solution. After pollination, bag the flowers and mark them in time.

2. The method for overcoming the distant hybridization barrier of Lagerstroemia indica and Lythrum salicaria by utilizing gibberellins as claimed in claim 1, wherein: In step 1), the time for emasculation is 4:00 to 6:00 in the morning under clear and windless weather.

3. The method for overcoming the distant hybridization barrier of Lagerstroemia indica and Lythrum salicaria by utilizing gibberellins as claimed in claim 1, wherein: In step 2), the variety of crape myrtle is 'Pink Crystal', and 250 mg·L of acetic acid is evenly sprayed on the pistil stigma of 'Pink Crystal' after emasculation and before pollination. -1 Gibberellin solution.

4. The method for overcoming the barrier of distant hybridization between Lagerstroemia indica and Lythrum salicaria by utilizing gibberellins as claimed in claim 1, wherein: In step 2), the variety of crape myrtle is 'Duohua Zi', and 250 mg·L -1 Gibberellin solution.

5. The method for overcoming the distant hybridization barrier of Lagerstroemia indica and Lythrum salicaria by utilizing gibberellins as claimed in claim 1, wherein: In step 2), the variety of crape myrtle is 'Pink Crystal', and 200 mg·L of chloranthate is evenly sprayed on the pistil stigma of 'Pink Crystal' after emasculation and before pollination. -1 Gibberellin solution.

6. The method for overcoming the distant hybridization barrier of Lagerstroemia indica and Lythrum salicaria by utilizing gibberellins as claimed in claim 1, wherein: In step 2), the variety of crape myrtle is 'Duohua Zi', and 200 mg·L is evenly sprayed on the pistil stigma of 'Duohua Zi' after emasculation and before pollination. -1 Gibberellin solution.

7. The method for overcoming the distant hybridization barrier of Lagerstroemia indica and Lythrum salicaria by utilizing gibberellins as claimed in claim 1, wherein: In step 3), the pollination time is between 9:00 and 10:00 in the morning under clear and windless weather.

8. The method for overcoming the distant hybridization barrier of Lagerstroemia indica and Lythrum salicaria by utilizing gibberellins as claimed in claim 1, wherein: In step 1), the tweezers are disinfected with 75% (v / v) alcohol solution.

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