Australian water lily pollination, seedling sowing and flowering phase regulation and control method

Abstract

The invention discloses an Australian water lily pollination, seedling sowing and flowering phase regulation method, which comprises the following steps: selecting an Australian water lily variety with good fructification as a female parent, and selecting an Australian water lily variety with sufficient pollen as a male parent; when the environment temperature is 28-32 DEG C, male parent pollen and purified water are mixed to form pollen liquid, and the female parent stigma disc is pollinated; seeds which are mature after being pollinated and developed for 22-30 days underwater are obtained, and the seeds are placed in purified water to be subjected to immersion culture until the seeds germinate; the germinated seeds are sown in a sowing matrix for cultivation, and seedlings are obtained; transplanting the seedlings to a field or a planting tank, and performing water level management; before the target flowering phase, according to a preset time sequence, the plants are subjected to pruning, slow release fertilizer applying, gibberellin spraying and compound fertilizer applying in sequence. The method provided by the invention realizes simplification and purification of pollination operation, improvement of germination and seedling rate, cleanness maintenance of seedling culture water and precise and centralized regulation and control of flowering phase.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of ornamental plant cultivation and breeding, in particular relates to a method for pollination, seedling and flowering regulation of Nymphaea hybrid. BACKGROUND

[0002] Nymphaeaceae Nymphaea L. plants are important ornamental aquatic flowers worldwide. Among them, the varieties of Nymphaea subg. Victoria (including its original species, cultivated varieties and hybrids) have attracted widespread attention in recent years as cut flowers and water landscape materials due to their beautiful flower shape, large flowers and erect flower stems. Nymphaea Nymphaea Anecphya subg.

[0003] In hybrid breeding, successful pollination of Nymphaea hybrid depends on the secretion of the stigma liquid on the first day of flowering. The existing technology usually adopts the method of collecting the stigma liquid of the female parent first, then mixing the pollen of the male parent anther and injecting it back into the female parent stigma disc for artificial pollination. However, this method has the following obvious defects: first, the amount of single flower stigma liquid secretion is small, and it often needs to collect the secretion liquid of 3 to 5 flowers to complete one pollination, which is complicated and inefficient; second, Nymphaea hybrid is usually planted in a deep water environment of 30 to 50 cm, and personnel need to identify flower status and work in water for a long time, which is inconvenient and has safety hazards (because Nymphaea only secretes stigma liquid on the first day of flowering); third, the stigma liquid collected in an open environment is easily contaminated by external pollen, affecting the accuracy of the identification of the hybrid offspring.

[0004] In seedling, light and temperature are the key environmental factors affecting seed germination and seedling quality of Nymphaea hybrid. Although some studies have proposed that 35-37℃ can promote seed germination, there is still a lack of systematic research on the optimal light intensity (or shading rate); in the aspect of seeding substrate, garden soil or mud pond soil is commonly used for direct sowing in the industry. This method easily leads to uneven distribution of seeds, low germination rate, and turbidity of water body during subsequent seedling transplanting, which affects the observation and operation of seedlings and seriously affects the transplanting efficiency; in the aspect of flowering regulation, in order to realize the opening of Nymphaea hybrid in a specific period (such as holidays) to achieve the best ornamental effect, it is necessary to accurately regulate the flowering time. However, there is no mature scheme for the flowering regulation technology of Nymphaea hybrid in the existing public literature and patents.

[0005] In summary, the existing technology has obvious deficiencies in the aspects of hybrid pollination efficiency and purity guarantee, optimal light and temperature conditions for seed germination, clean and efficient seedling substrate, and accurate flowering regulation of Nymphaea hybrid, which restricts the development of its breeding and ornamental application. SUMMARY

[0006] ​​The present application aims to provide an Australian water lily pollination, seedling breeding and flowering period regulation method, solve the problems of complex hybrid pollination process, difficult control of purity, unknown light and temperature conditions for seedling breeding, easy pollution of water body for seeding substrate, and irregular flowering period in the prior art, so as to realize the simplification and purification of pollination operation, the improvement of germination and seedling rate, the cleaning and maintenance of water body for seedling breeding, and the accurate and concentrated regulation of flowering period.

[0007] The technical scheme adopted by the present application is an Australian water lily pollination, seedling breeding and flowering period regulation method, comprising the following steps: Step S1: selecting an Australian water lily variety with good seed setting as the female parent and an Australian water lily variety with sufficient pollen as the male parent; when the environmental temperature is 28-32℃, mixing the pollen of the male parent with pure water to form a pollen solution, and pollinating the stigma disc of the female parent; Step S2: obtaining seeds that have developed maturely underwater for 22-30 days after pollination, immersing and culturing the seeds in pure water until germination; seeding the germinated seeds in a seeding substrate for cultivation to obtain seedlings; transplanting the seedlings to a field or a planting tank and managing the water level; Step S3: before the target flowering period, sequentially performing pruning, slow-release fertilizer application, gibberellin spraying and compound fertilizer application on the plants according to a preset time sequence.

[0008] Further, in step S1, the pollination time is from 9 am to 12 pm.

[0009] Further, in step S2, the immersion culture comprises: placing the seeds in pure water with a liquid level 3-5 cm higher than the seeds, first culturing at 30-35℃ in complete darkness for 3 days, and replacing the pure water every day, and then culturing at 30-35℃ under the condition of 76%-80% shading rate until the bud length is 2-3 cm. Further, in step S2, the seeding substrate is water grass mud, the seeding depth is 0.5-1.0 cm, and the seedlings are cultivated at 30-35℃ under the condition of 50%-70% shading rate until the seedlings grow 3-5 leaves with a diameter greater than 3 cm.

[0010] Further, in step S2, the water level is maintained at 5 cm at the initial stage of transplanting, and then gradually increased to 30-50 cm.

[0011] Further, in step S3, one month before the target flowering period, all flower buds exposed to the water surface are removed, only 3-5 mature leaves are reserved, and slow-release fertilizer is applied; three weeks, two weeks and one week before the target flowering period, a gibberellin solution with a concentration of 100-150 mg / L is sprayed, and the opened flower buds and yellow and rotten leaves are removed; one week before the target flowering period, compound fertilizer is applied, and the opened flower buds and yellow and rotten leaves are removed.

[0012] Further, the slow-release fertilizer is specifically 60-90 grams of slow-release fertilizer with a N-P-K content ratio of 12-8-19, applied within a radius of 20-30 cm from the root of the plant and buried 30 cm deep below the soil surface. The compound fertilizer is specifically 30 grams of compound fertilizer with a N-P-K content ratio of 15-15-15, applied within a radius of 20-30 cm from the root of the plant and buried 30 cm deep below the soil surface.

[0013] The beneficial effects of the present application are: 1. The present application uses pure water instead of nectar to pollinate, which eliminates the cumbersome steps of collecting nectar, significantly simplifies the operation process, improves the pollination efficiency, effectively avoids foreign pollen pollution, ensures the certainty and uniqueness of hybrid parents, and does not affect the seed setting rate and normal seed development.

[0014] 2. The present application determines the optimal light and temperature conditions for seedling of Australian water lily seeds, and significantly improves the seed germination rate and seedling quality by dark culture followed by light-shield culture at 30-35 DEG C and 76-80% light-shield rate, providing a reliable basis for standard seedling.

[0015] 3. The present application uses water grass mud as a seeding substrate, which effectively avoids turbidity of water body, maintains clear water quality, facilitates transplanting operation, and can be used repeatedly for 3 months without additional fertilization, reducing management cost.

[0016] 4. The present application realizes precise regulation of Australian water lily flowering period by using pruning, differential fertilization and spraying 100-150 mg / L gibberellin, promotes normal development of flower buds, and makes them bloom in a specific time, achieving the best ornamental effect. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0018] Figure 1 is a flow chart of the method of the present application. DETAILED DESCRIPTION

[0019] Clearly, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present application.

[0020] As Figure 1 shown, an Australian water lily pollination, seedling breeding, and flowering period regulation method provided by the embodiment includes the following steps. Step S1: hybrid parent selection: to achieve breeding goals and ensure hybrid success rate, select an Australian water lily variety (species) with good seed setting as the female parent, and select a variety (species) with sufficient pollen as the male parent.

[0021] Step S2: pollination time confirmation: the pollination and seed development of Australian water lily are significantly affected by temperature, and the optimal growth temperature (30-35℃) is different from the best pollination temperature (28-32℃). The appropriate pollination period is when the environmental temperature is stably maintained at 28-32℃. In South China, this period usually occurs in May and June and October and November each year. In other regions, pollination can be performed when the temperature stably reaches the range according to local weather conditions. The best time for a single day pollination is from 9:00 to 12:00.

[0022] Step S3: pollination operation: take a 2-ml centrifuge tube, add 1.5 ml of pure water, use tweezers to clamp an appropriate amount of mature stamens of the male parent into the centrifuge tube, and use a pipette or a pipettor to repeatedly blow and mix to make the pollen fully dispersed in the pure water until the liquid appears yellow. Use a pipette or a pipettor to suck the stigma secretion in the stigma disc of the female parent and discard it, and then suck the pure water mixed liquid containing pollen in the centrifuge tube and inject it into the stigma disc of the female parent to complete the pollination.

[0023] Step S4: seedling breeding: after successful pollination, the Australian water lily fruit develops and matures underwater for 22-30 days. Collect the seeds and clean them, place them in pure water with the liquid level 3-5 cm above the seeds, cultivate them at 30-35℃ in complete darkness for 3 days, and replace the pure water every day. Then, transfer them to an environment with a shading rate of 76%-80% and a temperature of 30-35℃ for further cultivation for 5-10 days. When the length of the germinating sprout reaches 2-3 cm, the seeds can be sown.

[0024] Step S5: Sowing and Seedling Raising: Use aquatic plant mud as the sowing substrate; spread the aquatic plant mud evenly in the seedling frame, with a thickness of no less than 3 cm; then add water so that the water level is 3-5 cm above the aquatic plant mud layer, and level the mud surface by scraping or manually; Australian water lily seeds are 0.2-0.3 cm in diameter, which is a relatively large type among tropical water lilies; use tweezers to insert the germinated seeds with a bud length of 2-3 cm into the aquatic plant mud at a depth of 0.5-1.0 cm, with a spacing of about 3 cm between seeds; place the seedling frame in an environment with a temperature of 30-35℃ and a shading rate of 50%-70% for cultivation; after cultivation, when the seedlings have grown 3-5 leaves with a diameter greater than 3 cm (usually about 3 months), they can be transplanted; handle carefully during transplanting to keep the root system as intact as possible.

[0025] Step S6: Transplanting and Management: Transplant the seedlings to the field or planting containers; initially, maintain the water level at about 5cm; as the plants grow, gradually raise the water level to 30-50cm; after transplanting, implement routine water and fertilizer management.

[0026] Step S7: Flowering Period Control: In South China, the peak flowering period for Australian water lilies is generally from May to November, while in other regions it is mostly from July to October. To ensure that the plants bloom uniformly on specific dates (such as holidays) during the peak flowering period for the best viewing effect, the following timing control can be implemented: (1) One month (or four weeks) before a specific date: Remove all flower buds that have emerged above the water surface; retain 3-5 mature leaves and remove all other leaves above the water surface; at the same time, apply fertilizer to each plant: apply Osmocote 328S slow-release fertilizer with an NPK content ratio of 12-8-19 (by total mass percentage) within a radius of 20-30 cm around the plant root, using 60-90 grams (i.e., 2-3 packs, 30 grams per pack), and bury it about 30 cm below the soil surface.

[0027] (2) Operations three weeks, two weeks and one week before a specific date: Spray the leaves and flower buds with a gibberellin (GA3) solution with a concentration of 100~150 mg / L, and promptly remove any open flower buds, yellow leaves and rotten leaves during the period.

[0028] (3) One week before the specific date: For each plant, apply a compound fertilizer of the Meiji type with an NPK content ratio of 15-15-15 (by total mass percentage) in a circle with a radius of 20-30 cm, centered on the root. The amount used is 30 grams (i.e., 2 packs, each pack containing 15 grams), and bury it about 30 cm below the soil surface. At the same time, remove any flower buds that have opened during this period, as well as yellow and rotten leaves.

[0029] One week after the above treatment (i.e., on the originally scheduled date), the plant can achieve concentrated flowering, with most flowers blooming on the first to second day after opening, reaching the best viewing condition.

[0030] Existing methods for hybridizing water lilies heavily rely on collecting stigma sap from the female parent to suspend pollen from the male parent, a cumbersome process. For Australian water lilies, the amount of stigma sap secreted per flower is small, often requiring the collection of stigma from 3 to 5 flowers for a single pollination. Furthermore, this method is inefficient and poses safety risks in deep water environments. In addition, stigma sap collected outdoors is susceptible to contamination by foreign pollen, affecting the accuracy of paternal identification in hybrid offspring. This invention solves these problems by using purified water instead of stigma sap for pollination. This method eliminates the tedious step of collecting stigma sap, making pollination more time-saving and convenient, while effectively avoiding pollen contamination and ensuring the certainty and uniqueness of the hybrid parents.

[0031] To verify the effectiveness of this invention, several Australian water lily hybridization experiments were designed, as shown in Table 1. The female parent included Australian water lily varieties such as 'Firefly', 'Purple White', 'Viola', and 'Purple Star', while the male parent included Australian water lily varieties such as 'Wedding Dress', 'Firefly', 'Robin', and 'Medea'. Pollination was concentrated in May and June 2024 (some extended to 2025). Three pollination methods were compared: using stigma secretions (traditional method), using purified water (the method of this invention), and not using any liquid (control). Key evaluation indicators included the number and developmental status of harvested pods, the average number of seeds per pod, and seed maturity.

[0032] Experimental results showed that pollination with purified water did not negatively affect the seed setting rate; most varieties achieved good seed setting and normal seed development. Table 1 shows that in different hybrid combinations, the pod development, harvest quantity, seed quantity, and maturity of pods pollinated with purified water were equal to or higher than those of the traditional stigma-based pollination method. In contrast, direct dry pollination resulted in unproductive flowers, indicating that a liquid medium is a necessary condition for successful pollination, and purified water can completely replace stigma-based pollination in this function.

[0033] Table 1. Statistics on pollination and seed set rate and seed quantity of different Australian water lily hybrid combinations.

[0034] Continued:

[0035] While existing technologies have studied the germination temperature of Australian water lily seeds, they have not conducted detailed research on the crucial influencing factor of light intensity (shading rate). Light conditions significantly affect the germination rate and seedling quality of water lily seeds. This invention further clarifies the optimized seedling cultivation conditions for Australian water lily seeds: After cleaning the harvested seeds, add purified water to submerge them by 3-5 cm, and cultivate them in the dark at 30-35℃ for 3 days, changing the water daily; then transfer them to an environment with a shading rate of 76-80% for continued cultivation, maintaining the temperature at 30-35℃. After 5-10 days, when the germinating shoots reach a length of 2-3 cm, they can be sown.

[0036] To determine the optimal light conditions, this study conducted experiments with five different shading rate gradients, as shown in Table 2. The data in Table 2 indicate that the germination rates of different Australian water lily hybrid seeds varied significantly under different shading conditions. Under shading rates of 76-80%, the seeds of varieties 'Zichen', 'Zibai', 'Jiaorenlei', 'Liusu', and 'Mengfangfei' all achieved the highest germination rates (e.g., germination rates of 85%, 90%, 91%, 88%, and 86% respectively on day 5), significantly better than other light conditions.

[0037] Table 2. Germination rate statistics of 100 different Australian water lily hybrid seeds under different shading conditions.

[0038] The observation results of seedling growth in Table 3 further confirm that under a shading rate of 76-80%, the seedlings of all varieties grew well, the plants sprouted uniformly, and there was no obvious sunburn or etiolation. However, under full light or excessively low shading conditions, the seedlings generally showed problems such as being short, sunburned, and underdeveloped. Excessively high shading rates (such as complete darkness) led to etiolation and poor growth in some seedlings.

[0039] Table 3. Growth status of seedlings from 100 different Australian water lily hybrid seeds under different shading conditions

[0040] The above experimental results prove that the seedling conditions determined by this invention (30-35℃ combined with 76-80% shading rate) are the optimal conditions for the growth of Australian water lily seedlings, effectively improving the quality of seedlings and providing reliable technical support for the hybridization breeding of Australian water lilies.

[0041] Existing Australian water lily seed propagation techniques typically involve directly sowing seeds in garden soil or pond soil, which suffers from low germination rates, overcrowding leading to seedling damage during transplanting, and turbid water and inconvenient handling during seedling collection. To address these shortcomings, this invention uses aquatic plant mud as the sowing substrate. Made from calcined natural soil, its granules have a microporous structure that adsorbs suspended solids and harmful organic matter, maintaining water clarity. It is also rich in various nutrients, slowly releasing and providing continuous fertilization. No additional fertilization is needed during the approximately three-month seedling period, preventing eutrophication and saving costs. Practical experience shows that using aquatic plant mud results in seed germination time and rates that are no less than, and often better than, those using garden soil. Furthermore, the substrate structure is stable, reusable, effectively promoting seedling growth and simplifying transplanting.

[0042] To verify the effectiveness of this invention, a comparative experiment was conducted, as shown in Table 4. The data in Table 4 show the germination and growth of different Australian water lily hybrid seeds in garden soil and sphagnum moss substrates. The experimental results indicate that using sphagnum moss substrate resulted in a higher final germination rate, a shorter time required to reach suitable transplanting conditions, and a significant increase in the fresh weight of seedling roots. For example, in different hybrid combinations, the fresh weight of roots in the sphagnum moss group was generally about 15%–30% higher than that in the garden soil group, and the germination rate increased by about 5–10 percentage points. This fully demonstrates that sphagnum moss has a significant promoting effect on the germination of Australian water lily seeds and the growth of seedlings.

[0043] Table 4. Statistics on germination and growth status of different Australian water lily hybrids in garden soil and aquatic plant mud.

[0044] In existing technologies, the flowering period of Australian water lilies is relatively short, typically only about 4 days, with the optimal viewing period concentrated in the first two days of flowering. Afterward, the flowers become less open and the flower stalks become bent, severely impacting the landscape effect. Furthermore, the uneven flowering time makes it difficult to achieve concentrated blooming on specific dates, limiting its application in festive landscaping. Currently, no publicly reported techniques exist for regulating the flowering period of Australian water lilies. To address these issues, this invention involves applying different types and amounts of fertilizer twice at specific times, combined with pruning flowering branches and removing some old and decaying leaves to regulate nutrient distribution, and supplemented by three sprays of a 100-150 mg / L gibberellin (GA3) solution to synergistically promote flower bud differentiation and development, thereby increasing the number of flowers and concentrating the flowering period, allowing the plant to reach its peak bloom during the target time.

[0045] To determine the optimal conditions for gibberellin application, we conducted experiments on concentration and number of applications, as shown in Table 5. The results in Table 5 show that different Australian water lily varieties exhibited significant differences in the number of deformed flower buds, the time to full bloom, and the total number of flower buds under different GA3 concentrations. At concentrations of 100 mg / L and 150 mg / L, flower buds were free of deformities, the full bloom period was advanced, and the number of flower buds was significantly increased, demonstrating a promoting effect at low concentrations and an inhibitory effect at high concentrations.

[0046] Table 5. Effects of different gibberellin concentrations on flowering of Australian water lilies after 7 days.

[0047] Continued:

[0048] As shown in Table 6, under the condition of 150 mg / L GA3, the number of sprays had a significant impact on the flowering promotion effect. When sprayed 3 times, the total number of flowers and buds for each variety reached its maximum within one week. Taking the 'Violet' variety as an example, after 3 sprays, the total number of buds was approximately twice that of the control group, indicating the most significant flowering promotion effect.

[0049] Table 6. Effects of 150 mg / L gibberellin concentration on flowering of Australian water lilies.

[0050] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for pollination, seedling raising, sowing, and flowering period control of Australian water lilies, characterized in that, Includes the following steps: Step S1: Select an Australian water lily variety with good fruit setting as the female parent and an Australian water lily variety with abundant pollen as the male parent; when the ambient temperature is 28–32℃, mix the pollen of the male parent with pure water to form a pollen solution and pollinate the stigma disc of the female parent. Step S2: Obtain seeds that mature underwater after pollination for 22-30 days, immerse the seeds in pure water until germination; sow the germinated seeds in a seeding substrate to cultivate seedlings; transplant the seedlings to the field or planting container and manage the water level. Step S3: Before the target flowering period, prune the plants, apply slow-release fertilizer, spray gibberellin, and apply compound fertilizer in sequence according to the preset time.

2. The method for pollination, seedling raising, sowing, and flowering period control of Australian water lilies according to claim 1, characterized in that, In step S1, the pollination time is from 9:00 AM to 12:00 PM.

3. The method for pollination, seedling raising, sowing, and flowering period control of Australian water lilies according to claim 1, characterized in that, In step S2, the immersion culture includes: placing the seeds in pure water at a level 3-5 cm above the seeds, first culturing them at 30-35°C in complete darkness for 3 days, changing the pure water daily, and then culturing them at 30-35°C with a shading rate of 76%-80% until the sprouts are 2-3 cm long.

4. The method for pollination, seedling raising, sowing, and flowering period control of Australian water lilies according to claim 1, characterized in that, In step S2, the sowing substrate is aquatic plant mud, the sowing depth is 0.5~1.0 cm, and the seedlings are cultivated at 30~35℃ and shading rate of 50%~70% until the seedlings grow 3~5 leaves with a diameter greater than 3cm.

5. The method for pollination, seedling raising, sowing, and flowering period control of Australian water lilies according to claim 1, characterized in that, In step S2, the water level is maintained at 5 cm in the early stage of transplanting, and then gradually raised to 30-50 cm.

6. The method for pollination, seedling raising, sowing, and flowering period control of Australian water lilies according to claim 1, characterized in that, In step S3, one month before the target flowering period, all flower buds exposed above the water surface are removed, leaving only 3 to 5 mature leaves, and slow-release fertilizer is applied; three weeks, two weeks, and one week before the target flowering period, a gibberellin solution with a concentration of 100-150 mg / L is sprayed and open flower buds, as well as yellow and rotten leaves, are removed; one week before the target flowering period, compound fertilizer is applied and open flower buds, as well as yellow and rotten leaves, are removed.

7. The method for pollination, seedling raising, sowing, and flowering period control of Australian water lilies according to claim 6, characterized in that, The application of slow-release fertilizer specifically involves applying 60 to 90 grams of slow-release fertilizer with an NPK content ratio of 12-8-19 within a radius of 20 to 30 centimeters, centered on the plant roots, and burying it 30 centimeters below the soil surface. The application of compound fertilizer specifically involves applying 30 grams of compound fertilizer with an NPK content ratio of 15-15-15 within a radius of 20 to 30 centimeters, centered on the plant roots, and burying it 30 centimeters below the soil surface.

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