Method for improving germination rate of eel grass seeds

Abstract

The invention provides a method for increasing the germination rate of eel grass seeds, which comprises the following steps: S1, activating the eel grass seeds by using growth hormone, so that the eel grass seeds are activated from a dormant state to obtain pretreated eel grass seeds; s2, the pretreated vallisneria natans seeds, underwater soil and water are mixed to obtain slurry, and the slurry is subjected to pill rolling treatment to obtain mud pills containing the vallisneria natans seeds; s3, the mud pills are coated with gypsum slurry, and the improved vallisneria natans seeds are obtained. According to the method, seed state regulation and control, nutrient microenvironment construction and mass transfer path optimization are organically combined, so that the germination rate of the eel grass seeds is remarkably increased, and the method is particularly suitable for evaluation and improvement treatment of the germination potential of the eel grass seeds under laboratory conditions.

Description

Technical Field

[0001] The present application relates to the field of plant cultivation technology, and in particular to a method for improving the germination rate of Vallisneria seeds. Background Art

[0002] Vallisneria Vallisneria natans Vallisneria spp. is a typical submerged plant with excellent water purification and ecological restoration capabilities. It is widely used in ecological restoration projects in freshwater bodies such as lakes, reservoirs, and rivers. In current aquatic ecological restoration practices, establishing a stable underwater vegetation layer with Vallisneria spp. can effectively improve water clarity, inhibit cyanobacterial blooms, and enhance the habitat of benthic animals. Therefore, the large-scale and efficient cultivation of Vallisneria spp. is gradually becoming a key research and engineering focus.

[0003] Compared to traditional plant transplanting, propagation using Vallisneria seeds offers advantages such as convenient resource acquisition, stable storage and transportation, and high sowing efficiency. This makes it particularly suitable for restoration scenarios involving large water areas, complex bottoms, and tight construction schedules. However, existing technologies for using Vallisneria seeds to restore aquatic ecosystems generally face the problem of low seed germination rates, which has become a key obstacle to their widespread and large-scale application.

[0004] Specifically, Vallisneria seeds have a strong natural dormancy and are very demanding on the germination environment. They are easily affected by temperature, moisture, oxygen, and substrate conditions, making it difficult to successfully complete germination in the natural state. At the same time, during the actual sowing or seedling raising process, seeds often fail to germinate or have a low seedling rate due to shedding, water impact, microbial infection, or lack of nutritional support. Some studies have attempted to improve the seed state and external environment through coating, hormone treatment, substrate optimization, etc., but it is still difficult to fundamentally solve the problems of slow germination, uneven seedling formation, and poor transplant adaptability.

[0005] Therefore, how to improve the germination success rate of Vallisneria seeds in artificial seedling cultivation or natural release environments is a key technical issue that urgently needs to be broken through in this field. Summary of the Invention

[0006] The present application provides a method for improving the germination rate of Vallisneria seeds. By introducing hormone activation treatment, a core structure constructed based on underwater soil, and an outer shell coating system, the synergistic optimization of seed dormancy release, nutrient supply, and water regulation is achieved, thereby significantly improving the germination rate and germination uniformity of Vallisneria seeds.

[0007] In a first aspect, the present application provides a method for improving the germination rate of Vallisneria seeds, comprising the following steps: S1: activating the Vallisneria seeds with growth hormone to activate the Vallisneria seeds from a dormant state, thereby obtaining pretreated Vallisneria seeds; S2: mixing the pretreated Vallisneria seeds, bottom soil and water to obtain a slurry, and then rolling the slurry into pellets to obtain mud pellets containing Vallisneria seeds; S3: coating the mud balls with gypsum slurry to obtain improved Vallisneria seeds.

[0008] According to the present application, the method significantly improves the germination rate of Vallisneria seeds by organically combining seed state regulation, nutrient microenvironment construction and mass transfer path optimization, and is particularly suitable for the evaluation and improvement of the germination potential of Vallisneria seeds under laboratory conditions.

[0009] Specifically, step S1 activates the Vallisneria seeds through growth hormones, which is different from the method of mixing hormones with coating materials in related technologies. In contrast, pre-treatment can not only achieve rapid absorption and endogenous activation of hormones, but also accurately control the hormone concentration and action time before coating, thereby more effectively breaking dormancy, promoting enzyme activation and cell metabolism activation. However, the existing co-coating method has problems such as slow hormone release, uneven mass transfer and delayed timeliness, resulting in asynchronous activation between individual seeds, affecting the uniformity and efficiency of germination. Through early activation, it can be ensured that the seeds have started the germination-related physiological processes before coating, and smoothly complete water absorption and germination radicle extension under the protection of subsequent coating.

[0010] In step S2, underwater soil is used as the matrix for rolling the pellets, which is different from the conventional method of using inorganic powders such as bentonite, diatomaceous earth, and vermiculite as pellet nucleating materials or intermediate layer materials. The underwater soil itself is the natural growth environment of submerged plants such as Vallisneria, which is rich in humus, organic carbon sources, nitrogen and phosphorus nutrients, and adaptive microbial communities, and has significant ecological adaptability. In the present application, the underwater soil not only plays a physical support and shaping role in the pellet forming process, but more importantly, it constructs a natural-like microhabitat inside the pellet structure, while maintaining good permeability and water retention capacity, providing nutrients that can be absorbed and utilized by germinating seeds, thereby effectively supporting the growth and development of the early radicle.

[0011] In contrast, although traditional inorganic mineral materials such as bentonite and vermiculite have certain adsorption properties and mechanical strength, they themselves do not have bioavailable nutrients and are difficult to provide continuous physiological support for seeds. Moreover, the coating structure is often highly dense and lacks biodegradability, which may limit water penetration and root penetration.

[0012] In addition, the underwater mud, as a forming matrix, can also be directly integrated into the destination environment during subsequent water body transplantation, reducing the physical and chemical adaptation barriers between the seeds and the new environment, and significantly improving the success rate of transplantation. This "grow and plant" concept has not been widely used in the existing technology, reflecting the unique conception and engineering transformation potential of this application from the perspective of "ecological continuity". It should also be noted that Vallisneria is a typical submerged plant, and its seeds can generally germinate and establish in the early stage in a submerged, low-light, and bottom mud environment. The naturally deposited bottom mud at the bottom of various water bodies has the basic conditions to support the germination of Vallisneria seeds.

[0013] Step S3 uses gypsum slurry to coat the mud balls, forming an outer shell layer that is initially stable and has a microporous structure. On the one hand, after the gypsum hardens, it forms a porous skeleton, which is conducive to the inward conduction of water, ensuring that the seeds can continue to absorb water in the underwater environment; on the other hand, the outer shell structure gradually softens and disintegrates during the water absorption process, and will not form a long-term mechanical obstacle. It can be released in time within the time window required for the germination of the seed radicle, ensuring smooth emergence. In addition, the calcium ions released by the gypsum during the curing process can also cross-link with some organic components in the bottom mud, further stabilizing the mud ball structure and adjusting its local pH, inhibiting the excessive growth of harmful microorganisms, and creating a more suitable microenvironment for seed germination.

[0014] The above three steps form a continuous and synergistic technical mechanism in terms of "physiological activation-nutrient supply-environmental regulation", effectively solving the technical problems of low germination rate, uneven germination and poor early viability of existing Vallisneria seeds in non-natural ecological environments (such as laboratories or restorative water bodies), and significantly improving the germination rate and germination uniformity of Vallisneria seeds.

[0015] In some embodiments, step S1 includes: The Vallisneria seeds were soaked in a 140-160 mg / L gibberellin aqueous solution for 20-30 hours and then air-dried to obtain pretreated Vallisneria seeds.

[0016] In some of the aforementioned embodiments, activation of Vallisneria seeds with a gibberellin aqueous solution prior to pelleting can significantly improve their germination rate and uniformity. By screening different types of plant growth regulators (e.g., gibberellin GA3 and indolebutyric acid IBA) and varying their concentrations, the inventors found that gibberellin exhibited optimal activation effects within a concentration range of 140-160 mg / L, maintaining a high germination rate without causing adverse reactions such as abnormal seed elongation or premature shelling, resulting in a relatively better activation effect.

[0017] Compared to the prior art method of co-blending growth hormones with coating materials, the hormone pre-treatment activation method employed in this application allows the gibberellins to be directly absorbed and utilized by the seeds. This avoids issues such as dose attenuation, release lag, and uneven contact efficiency during the coating diffusion release process, significantly shortening the physiological activation time of the seeds and improving overall germination synchronization and initial growth vigor. Furthermore, controlling the concentration of the activation solution and the treatment time ensures sufficient hormone absorption while preventing excessive expansion from interfering with the stability of the subsequent pelletized structure, thereby improving the consistency and yield of the preparation process.

[0018] Therefore, this activation treatment method is not only superior to the traditional method of co-encapsulating hormones in terms of germination effect, but also, combined with the screened and optimized hormone types and concentration ranges, can further improve the germination rate and germination uniformity of Vallisneria seeds.

[0019] In some embodiments, step S2 includes: 1000 parts of bottom soil, 30-50 parts of pretreated Vallisneria seeds and water were mixed to obtain mud with a moisture content of 35-40%, and the mud was pelletized to obtain mud pellets containing Vallisneria seeds with a diameter of 4-6 mm.

[0020] In some of the above-mentioned embodiments, by rationally controlling the mass ratio of underwater soil to Vallisneria seeds and the moisture content of the mud, the pellet forming process can ensure good mud coating and plasticity while avoiding the problems of loose mud pellet structure and drying shrinkage and cracking caused by excessive moisture. Specifically, controlling the seed feeding ratio between 30 and 50 parts is conducive to distributing an appropriate amount of seeds in each mud pellet, reducing resource competition among seeds and improving germination uniformity; controlling the moisture content between 35 and 40% can balance pellet forming and drying shrinkage control, ensuring pellet structural stability and consistency of the disintegration rate after immersion in water; controlling the mud pellet diameter within the range of 4 to 6 mm helps to ensure seed embedding integrity while increasing the effective water and gas diffusion efficiency per unit volume, thereby more quickly forming a suitable germination microenvironment after immersion in water, thereby further improving the germination rate and germination uniformity of Vallisneria seeds.

[0021] In some embodiments, step S2 includes: 1000 parts of bottom soil, 30-50 parts of pretreated Vallisneria seeds, 5-15 parts of ammonium bicarbonate and water were mixed to obtain mud with a water content of 35-40%, and the mud was pelletized to obtain mud balls containing Vallisneria seeds with a diameter of 4-6 mm.

[0022] In some of the above embodiments, further adding 5-15 parts of ammonium bicarbonate to the slurry can provide a slow-release nitrogen source around the seeds, enhancing the nutrient supply required for early germination, thereby promoting seed germination and seedling growth. Ammonium bicarbonate readily releases ammonia and carbon dioxide in a humid environment, which can adjust the pH value and increase the CO2 concentration in the microenvironment, helping to break the residual chemical dormancy of some seeds and enhance the efficiency of hormone action.

[0023] Ammonium bicarbonate also has a certain disintegration effect. Upon immersion in water, the released gas slightly expands the pellet structure, helping the seeds to more quickly expose themselves to a suitable moisture environment. This accelerates water penetration and material exchange, further synergistically improving seed germination rate and uniformity. Compared to solutions without ammonium bicarbonate, its addition effectively promotes microenvironment activation and kinetic energy release in the early stages of germination, resulting in a higher germination rate.

[0024] In some embodiments, step S3 includes: 100 parts of gypsum powder, 4 to 8 parts of hydrophilic polymer and water are mixed to obtain a gypsum slurry with a moisture content of 55% to 65%, and the mud balls are coated with the gypsum slurry to obtain improved Vallisneria seeds with a diameter of 5 to 7 mm; wherein the hydrophilic polymer includes sodium alginate and polyvinyl alcohol, and the mass ratio of the sodium alginate to the polyvinyl alcohol is 1:1.5 to 2.5.

[0025] In some of the above embodiments, gypsum, polyvinyl alcohol and sodium alginate cooperate to construct a composite shell with stable structure and good permeability. Gypsum, as an inorganic hardening component, can quickly harden and form, provide initial structural support and physical isolation, but it is brittle and prone to cracking or instability after absorbing water. Polyvinyl alcohol, as a flexible hydrophilic polymer, can form a continuous network structure in the gypsum skeleton, effectively alleviate the shell cracking caused by dry-wet changes, and give the shell a certain water retention and sustained release capacity; sodium alginate can react with the calcium ions released by gypsum to produce an ion cross-linking reaction to generate a uniformly distributed microgel network; thus, with the dissolution and dispersion of gypsum, the expansion effect of ammonium bicarbonate gas in the mud ball kernel and the germination drive of the seeds, the porosity of the outer shell gradually increases until it collapses. This process can guide external moisture, oxygen, etc. to slowly and orderly penetrate into the mud ball kernel area, thereby improving the stability of the mud ball kernel microenvironment, providing a good germination environment for the seeds, and improving the germination rate and germination uniformity of the seeds.

[0026] If gypsum is used alone as the shell material, it will indeed soften, become unstable, or even disintegrate over time in a wet environment. However, this process is relatively uncontrollable, making it difficult to regulate the water permeation rate and unable to provide a flexible sustained-release environment, which can easily lead to uneven hydration of Vallisneria seeds or premature inactivation. If only a single hydrophilic polymer (such as polyvinyl alcohol or sodium alginate) is mixed with gypsum, there will be problems such as single function and unstable structure: although polyvinyl alcohol can give the shell flexibility, due to the lack of cross-linking, its permeability regulation ability is limited, which can easily lead to uneven hydration rate. Although sodium alginate has ionic cross-linking ability, its gel membrane has low mechanical strength and is prone to premature detachment or forming an overly dense structure, which in turn hinders water vapor mass transfer.

[0027] The three work synergistically, combining structural stability, gradual mass transfer and flexible slow-release properties, which not only significantly enhances the mechanical properties and environmental responsiveness of the shell, but also provides a more stable and suitable microenvironment for seed germination, helping to improve the water utilization efficiency and respiratory flux of Vallisneria seeds, thereby significantly improving the germination rate and germination uniformity of Vallisneria seeds as a whole.

[0028] In some embodiments, the weight average molecular weight of sodium alginate is 80,000-150,000; and the weight average molecular weight of polyvinyl alcohol is 20,000-70,000.

[0029] In some embodiments, step S3 includes: 100 parts of gypsum powder, 4 to 8 parts of hydrophilic polymer, 1 to 3 parts of mannitol and water are mixed to obtain gypsum slurry with a moisture content of 55% to 65%, and the mud balls are coated with the gypsum slurry to obtain improved Vallisneria seeds with a diameter of 5 to 7 mm.

[0030] In some of the above embodiments, mannitol is further added to the composite shell layer, which helps to optimize the early permeability and germination initiation responsiveness of the shell layer. Gypsum, as the main inorganic hardening component, can gradually soften and crack after absorbing water, thereby realizing a conductive path for the release of water and oxygen to the seeds. However, the single gypsum system lacks effective regulation of the water permeation rate, and the disintegration process is greatly affected by environmental changes, and there is a risk of uneven germination timeliness. After the introduction of polyvinyl alcohol and sodium alginate, a composite shell with enhanced toughness can be constructed through the coordinated ionic cross-linking of flexible chain segments, giving it sustained-release properties and structural stability, but it may also fill and partially block the natural pores in the gypsum skeleton, thereby reducing the initial water vapor permeation efficiency.

[0031] On this basis, mannitol was further introduced as a soluble small molecule. Upon contact with water, it preferentially dissolves and migrates out of the shell, inducing the formation of microscopic cavities or porous channels in situ, thereby reconstructing the shell's early permeability pathways. This process does not compromise the overall mechanical stability of the shell, but significantly enhances the initial accessibility of external water and oxygen, facilitating the timely activation of Vallisneria seeds.

[0032] Compared with the shell structure without added mannitol, this embodiment not only ensures the sustained-release ability and the integrity of the support structure, but also has better osmotic regulation performance, which can provide a more balanced water-oxygen conduction environment in the early stage of germination, thereby effectively improving the starting efficiency, germination rate and germination uniformity of Vallisneria seeds.

[0033] In some embodiments, step S3 further includes: The mud balls coated with the gypsum slurry are allowed to stand for 4 to 8 hours for pre-solidification, so that the shell layer is initially shaped and then dried to obtain improved Vallisneria seeds.

[0034] In some of the aforementioned embodiments, a 4-8 hour pre-curing period after the coating process facilitates stress relief in the gypsum-polymer composite shell and gradual stabilization of the structural formation process. The gypsum slurry begins to hydrate and form a crystalline network shortly after mixing. If dried immediately and rapidly, uneven moisture distribution or differential shrinkage rates inside and outside the shell may lead to cracking, structural collapse, or shedding of the coating.

[0035] Setting a static pre-curing step of appropriate length can make the gypsum hydration process fully proceed in a mild environment, and at the same time, it can release Ca2+ from sodium alginate and gypsum. 2+ This provides ample time for ion migration and cross-linking, thereby enhancing the spatial uniformity of the microgel network. At the same time, the distribution and molecular orientation of the polyvinyl alcohol segments also tend to be stable, helping to build a denser, continuous, and flexible support structure.

[0036] During the pre-curing process, the internal stress of the composite shell is effectively released, which is beneficial to improving the overall strength and durability of the shell after drying, and avoiding structural instability caused by uneven shrinkage or stress accumulation. The prepared seed coating structure is more complete, dense, and more resistant to water erosion. The seeds maintain good shell integrity for a longer time in the water environment, thereby improving the controllability and safety of the subsequent germination process.

[0037] In some embodiments, the following steps are further included: S4: placing the improved Vallisneria seeds in a culture vessel and culturing them in a light incubator to obtain Vallisneria seedlings; wherein the culture vessel comprises bottom soil and water.

[0038] In some of the above embodiments, by setting a specific light culture environment, more favorable germination conditions are provided for the improved Vallisneria seeds, which is particularly suitable for early seedling cultivation or laboratory-scale seedling breeding. Compared with the fluctuations of factors such as light, water temperature, and bottom sediment in the natural water environment, the light incubator can achieve precise control of environmental temperature and photoperiod, which helps to break the hysteresis response of Vallisneria seeds to temperature and light changes, and improve their germination synchronization and overall germination rate; the bottom soil is set in the culture vessel, which not only plays a role in fixing the position of the seeds, but also can slowly release nutrients under water-saturated conditions, maintain a suitable rhizosphere microenvironment, and promote the radicle to grow downward and the seedlings to grow stably. This method is not only suitable for indoor domestication and cultivation of Vallisneria, but also provides a source of healthy seedlings for large-scale aquatic grass restoration.

[0039] In some embodiments, in step S4: The thickness of the bottom soil in the culture vessel is 3-4 cm, and the water depth is 6-7 cm.

[0040] In some of the above-mentioned embodiments, by controlling the ratio structure of the bottom mud and the water layer, the improved Vallisneria seeds are placed in a more favorable spatial environment, assisting them in completing the germination and colonization process. The thickness of the bottom soil of 3 to 4 cm can provide sufficient supporting medium and initial nutrient source for the Vallisneria seeds, which is conducive to the rapid penetration of the radicle into the shell and fixation in the bottom mud; at the same time, the pore structure of the mud layer within this thickness range still maintains good air permeability, avoiding excessive burial depth of the seeds or rotting due to lack of oxygen due to excessive thickness of the bottom mud. The 6 to 7 cm water layer can maintain a stable water temperature and provide a transparent light channel to ensure that the embryo obtains sufficient light energy during the emergence stage. The bottom mud and the water layer form a relatively stable microenvironment, which helps to balance the oxygen, moisture and temperature conditions, improve the germination rate and uniformity of the Vallisneria seeds, and is also conducive to the subsequent initiation of photosynthesis and biomass accumulation of the Vallisneria seedlings.

[0041] In some embodiments, in step S4: The culture conditions in the light incubator include: a temperature of 23-27° C., a light intensity of 1000-2000 lx, and a light cycle of 12 hours of light and 12 hours of darkness.

[0042] In some of the above embodiments, the above-mentioned light and temperature conditions simulate the typical environment of Vallisneria in late spring and early summer in its natural habitat, which helps to break its sensitivity to low temperature or photoperiod and significantly improve the germination rate and synchronization. The temperature is controlled in the range of 23~27℃, which is close to the optimal growth temperature range of Vallisneria, which can not only activate the metabolic activity of its hypocotyl cells, but also inhibit the occurrence of abnormal dormancy or temperature stress response; the light intensity is set to 1500lx, which can provide a mild but stable light stimulation for Vallisneria in the early germination stage, avoid strong light inhibition and effectively induce the directional elongation of the embryo; the use of a light cycle of 12h light and 12h dark can coordinate the initiation of photosynthesis and the accumulation of dark period substances, and enhance the extension of the embryo and the activity of seedling emergence. Compared with the method of not setting clear light and temperature conditions or adopting full darkness or full light cultivation, the regulation mode provided by this scheme is more conducive to the smooth completion of the whole process from germination to colonization of Vallisneria under indoor conditions.

[0043] In some embodiments, the underwater soil has a TN content of 4-6 mg / g, a TP content of 3-5 mg / g, and a TC content of 3 wt%-5 wt%.

[0044] In some of the aforementioned embodiments, the nutrient composition of the bottom soil is similar to that of eutrophic water sediments, possessing appropriate nitrogen, phosphorus, and carbon nutrient levels, providing essential nutritional support for Vallisneria seeds during germination and early seedling formation. TN (total nitrogen) and TP (total phosphorus), key factors in plant inorganic nutrition, promote root expansion and leaf differentiation, shortening the time window from germination to establishment. A moderate amount of TC (total carbon), reflecting the organic matter reserves in the bottom soil, provides the necessary microbial synergistic environment and slow-release nutrient source for seed germination. Compared to neutral or sandy substrates with low TN, TP, and TC content, this type of bottom soil creates a more root-friendly microbial environment with better nutrient buffering capacity, helping to increase seed viability and seedling emergence rates, further enhancing the adaptability and reproducibility of the overall method under controlled environments.

[0045] Compared with the prior art, the present invention has the following advantages: 1. This application uses gibberellin hormones to pre-treat and activate seeds, avoiding the problem of hormone migration with the coating and uneven release in the prior art, and improving the synchronization and start-up efficiency of the seed transition from dormancy to germination; 2. Using underwater soil instead of inorganic filling materials as the core of the mud ball not only provides a suitable seed embedding environment, but also enhances the adaptability of seeds to the aquatic substrate after germination, reducing the obstacles to transplanting or colonization; 3. The introduction of mannitol as a small molecule polyol forms a soluble cavity structure in the shell, significantly improving the initial permeability and water vapor conductivity, making the germination process smoother and the seed start-up faster; 4. Constructing a synergistic shell structure based on gypsum, polyvinyl alcohol, sodium alginate and mannitol achieves a balanced regulation of the coating's sustained-release protection and moisture / oxygen permeability, enhancing adaptability in the early stages of germination; 5. Setting clear cultivation conditions such as light, water depth, and bottom mud thickness has formed a standard system that can be used for experimental evaluation and seedling management, which is conducive to its promotion and use in laboratories or artificial seedling systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0047] Figure 1 This is a bar graph of the average germination rates of different growth hormones at different concentrations in this application.

[0048] in, Figure 1 In the horizontal axis, CK represents the blank group, 50IBA, 100IBA, 150IBA, and 200IBA represent the 50, 100, 150, and 200 mg / L indoleacetic acid aqueous solution treatment groups, respectively; 50GA3, 100GA3, 150GA3, and 200GA3 represent the 50, 100, 150, and 200 mg / L gibberellin aqueous solution treatment groups, respectively.

[0049] Figure 2 It is a schematic diagram of a process for improving the germination rate of Vallisneria seeds in one embodiment of the present application.

[0050] Figure 3 This is a schematic structural diagram of the improved Vallisneria seeds in one embodiment of the present application.

[0051] Figure 4 This is a physical picture of the improved Vallisneria seeds in one embodiment of the present application.

[0052] Explanation of the accompanying numbers: 1 is Vallisneria seeds; 2 is gibberellin aqueous solution; 3 is mud; 4 is mud ball containing Vallisneria seeds; 5 is gypsum slurry; 6 is improved Vallisneria seeds; 1-2 is bottom soil; 1-2 is pretreated Vallisneria seeds; 2-1 is gypsum shell. DETAILED DESCRIPTION

[0053] The various embodiments or implementation schemes in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments.

[0054] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with an embodiment or example is included in at least one embodiment or example of the present application. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0055] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0056] In the description of this specification, unless otherwise specified, "parts" refer to "parts by mass".

[0057] Below, the embodiment of the present application is described. The embodiment described below is exemplary and is only used to explain the present application, and is not to be construed as limiting the present application. Where specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. Reagents or instruments used that do not specify the manufacturer are conventional products that can be obtained commercially.

[0058] The bottom mud was collected from East Lake in Wuhan. The lake bottom mud was dried and ground, and then sieved with a 60-mesh sieve to obtain the bottom mud for use. After testing, its TN content was 5.40 mg / g, TP content was 4.05 mg / g, and TC content was 4.17 wt%; Sodium alginate, weight average molecular weight about 100,000; Polyvinyl alcohol, weight average molecular weight of about 50,000, degree of hydrolysis above 90%.

[0059] Screening of growth hormone and its concentration: The seeds of Vallisneria sinensis were air-dried for one day, and then soaked in 50, 100, 150, and 200 mg / L gibberellin aqueous solutions and 50, 100, 150, and 200 mg / L indolebutyric acid aqueous solutions for 24 hours, respectively. The seeds were then washed with pure water and set aside. The bottom of the tissue culture flask was covered with sediment collected from Wuhan East Lake to a thickness of 3-4 cm. Water was slowly added along the wall of the flask to a depth of 6-7 cm. The flask was left to stand for 24 hours before use. Sow the soaked Vallisneria seeds of each treatment group evenly into the culture bottles, with 30 seeds in each bottle, and set three replicates for each treatment group. Place the tissue culture flask in a light incubator set at 25°C, 1500 lx light intensity, and a photoperiod of 12 hours light and 12 hours dark. Observe and record the germination of the Vallisneria seeds daily for four consecutive weeks.

[0060] The germination rates of each group were Figure 1 As shown, 150 mg / L gibberellin aqueous solution had the greatest effect on the germination rate of Vallisneria seeds, with a germination rate of 43.3%. Indolebutyric acid had no obvious effect on the germination of Vallisneria seeds at the three concentrations.

[0061] Therefore, in the subsequent examples, 150 mg / L gibberellin aqueous solution was used to activate Vallisneria seeds.

[0062] Preparation Example 1 Preparation of gypsum slurry: Weigh 100 parts of gypsum powder, 2 parts of sodium alginate, 4 parts of polyvinyl alcohol, and 2 parts of mannitol for later use; Heat polyvinyl alcohol and dissolve it in an appropriate amount of water. Then add sodium alginate and mannitol to dissolve. Then, add gypsum powder and water step by step while stirring to avoid agglomeration. After dispersion is complete, add an appropriate amount of water to obtain gypsum slurry A with a moisture content of approximately 60%. (The gypsum slurry is ready for use and should be used within 30 minutes.) Preparation Example 2 Preparation of gypsum slurry: Weigh 100 parts of gypsum powder, 6 parts of sodium alginate, and 2 parts of mannitol for later use; Dissolve sodium alginate in an appropriate amount of water, then add mannitol to dissolve. Then, add gypsum powder and water step by step while stirring to avoid lumps. After dispersion is complete, add an appropriate amount of water to obtain gypsum slurry B with a moisture content of approximately 60%. (The gypsum slurry is ready for use and should be used within 30 minutes.) Preparation Example 3 Preparation of gypsum slurry: Weigh 100 parts of gypsum powder, 3 parts of sodium alginate, 3 parts of polyvinyl alcohol, and 2 parts of mannitol for later use; Dissolve sodium alginate in an appropriate amount of water, then add mannitol to dissolve. Then, add gypsum powder and water step by step while stirring to avoid lumps. After dispersion is complete, add an appropriate amount of water to obtain gypsum slurry C with a moisture content of approximately 60%. (The gypsum slurry is ready for use and should be used within 30 minutes.) Preparation Example 4 Preparation of gypsum slurry: Weigh 100 parts of gypsum powder, 1 part of sodium alginate, 5 parts of polyvinyl alcohol, and 2 parts of mannitol for later use; Dissolve sodium alginate in an appropriate amount of water, then add mannitol to dissolve. Then, add gypsum powder and water stepwise while stirring to avoid lumps. After dispersion is complete, add an appropriate amount of water to obtain gypsum slurry D with a moisture content of approximately 60%. (The gypsum slurry is ready for use and should be used within 30 minutes.) Preparation Example 5 Preparation of gypsum slurry: Weigh 100 parts of gypsum powder, 6 parts of polyvinyl alcohol, and 2 parts of mannitol for later use; Heat polyvinyl alcohol and dissolve it in an appropriate amount of water. Then add mannitol to dissolve it. Then, add gypsum powder and water step by step while stirring to avoid lumps. After dispersion is complete, add an appropriate amount of water to obtain gypsum slurry E with a moisture content of about 60%. (The gypsum slurry is ready for use and should be used within 30 minutes.) Preparation Example 6 Preparation of gypsum slurry: Weigh 100 parts of gypsum powder, 2 parts of sodium alginate, and 4 parts of polyvinyl alcohol for later use; Heat polyvinyl alcohol and dissolve it in an appropriate amount of water. Then add sodium alginate and dissolve it. Then, add gypsum powder and water step by step while stirring to avoid lumps. After dispersion is complete, add an appropriate amount of water to obtain gypsum slurry F with a moisture content of approximately 60%. (The gypsum slurry is ready for use and should be used within 30 minutes.) Preparation Example 7 Preparation of gypsum slurry: Weigh 100 parts of gypsum powder for later use; Add gypsum powder to water in steps while stirring to avoid lumps. After dispersion, add appropriate amount of water to obtain gypsum slurry G with a moisture content of about 60%. (The gypsum slurry is ready for use and should be used within 30 minutes) Example 1

[0063] Methods to improve the germination rate of Vallisneria seeds: Process flow such as Figure 2 As shown, plump, insect-free Vallisneria seeds were selected and immersed in a 150 mg / L gibberellin aqueous solution for 24 h. The seeds were taken out and dried at room temperature for 12 h to obtain pretreated Vallisneria seeds.

[0064] Weigh 1000 parts of underwater soil, add 40 parts of pretreated Vallisneria seeds, 10 parts of ammonium bicarbonate and an appropriate amount of deionized water, and use a blender to mix to form a mud slurry with a moisture content of 35%~40%; then use a ball rolling board to roll the mud into seed mud balls with a diameter of 4~6mm. After the mud balls are formed, let them stand in a ventilated and cool place for 2 hours to dry the surface to obtain mud balls containing Vallisneria seeds (each mud ball contains an average of 6 Vallisneria seeds).

[0065] The above mud balls were immersed in gypsum slurry A and rolled to form a shell layer with a thickness of about 0.5 mm. After coating, they were naturally dried at room temperature for 24 hours to form complete modified Vallisneria seeds. The structural diagram and the actual picture of the modified Vallisneria seeds are shown in the figure below. Figure 3 and Figure 4 shown.

[0066] Example 2 Methods to improve the germination rate of Vallisneria seeds: Select plump, insect-free Vallisneria seeds and soak them in a 150 mg / L gibberellin aqueous solution for 24 hours. Then take them out and air-dry them at room temperature for 12 hours to obtain pretreated Vallisneria seeds.

[0067] Weigh 1010 parts of bottom soil, add 40 parts of pretreated Vallisneria seeds and an appropriate amount of deionized water, and use a blender to mix to form a mud slurry with a moisture content of 35%~40%; then use a ball rolling board to roll the mud into seed mud balls with a diameter of 4~6mm. After the mud balls are formed, let them stand in a ventilated and cool place for 2 hours to dry the surface to obtain mud balls containing Vallisneria seeds (each mud ball contains an average of 6 Vallisneria seeds).

[0068] The clay balls were immersed in gypsum slurry A and rolled to form a shell layer with a thickness of about 0.5 mm. After coating, they were left to dry naturally at room temperature for 24 hours to form complete modified Vallisneria seeds.

[0069] Example 3 Methods to improve the germination rate of Vallisneria seeds: The method is substantially the same as Example 1, except that gypsum slurry B is used instead of gypsum slurry A.

[0070] Example 4 Methods to improve the germination rate of Vallisneria seeds: The method is substantially the same as Example 1, except that gypsum slurry C is used instead of gypsum slurry A.

[0071] Example 5 Methods to improve the germination rate of Vallisneria seeds: The method is substantially the same as Example 1, except that gypsum slurry D is used instead of gypsum slurry A.

[0072] Example 6 Methods to improve the germination rate of Vallisneria seeds: The method is substantially the same as Example 1, except that gypsum slurry E is used instead of gypsum slurry A.

[0073] Example 7 Methods to improve the germination rate of Vallisneria seeds: The method is substantially the same as Example 1, except that gypsum slurry F is used instead of gypsum slurry A.

[0074] Example 8 Methods to improve the germination rate of Vallisneria seeds: The method is substantially the same as Example 1, except that gypsum slurry G is used instead of gypsum slurry A.

[0075] Comparative Example 1 Methods to improve the germination rate of Vallisneria seeds: Select plump, insect-free Vallisneria seeds and soak them in a 150 mg / L gibberellin aqueous solution for 24 hours. Then take them out and dry them at room temperature for 12 hours to obtain pretreated Vallisneria seeds as improved Vallisneria seeds.

[0076] Comparative Example 2 Methods to improve the germination rate of Vallisneria seeds: Select plump, insect-free Vallisneria seeds and soak them in a 150 mg / L gibberellin aqueous solution for 24 hours. Then take them out and air-dry them at room temperature for 12 hours to obtain pretreated Vallisneria seeds.

[0077] Weigh 900 parts of underwater mud, add 100 parts of gypsum powder, 40 parts of pretreated Vallisneria seeds, 10 parts of ammonium bicarbonate and an appropriate amount of deionized water, and use a stirrer to mix to form a mixed mud with a moisture content of 35%~40%; then use a ball rolling board to roll the mixed mud into seed balls with a diameter of 4~6 mm. After the seed balls are formed, they are placed in a ventilated and cool place for 2 hours for surface drying to obtain seed balls containing Vallisneria seeds (each seed ball contains an average of 6 Vallisneria seeds), which are used as improved Vallisneria seeds.

[0078] Test part: Cover the bottom of the tissue culture bottle with bottom soil to a thickness of 3-4 cm, slowly add water along the bottle wall to a depth of 6-7 cm, and let it stand for 24 hours before use; After drying, the modified Vallisneria seeds obtained in each Example and Comparative Example were placed in culture bottles, with 5 seeds per bottle (30 seeds in Comparative Example 1). Each treatment group had three replicates. The seeds were then cultured in a light incubator set at 25°C, 1500 lx light intensity, and a photoperiod of 12 hours of light and 12 hours of darkness. The germination of the Vallisneria seeds was observed and recorded daily for four consecutive weeks. The average germination rate, germination onset time, and the percentage of seeds that germinated within 3 days after the onset of germination (as an indicator of germination uniformity) were calculated and shown in Table 1.

[0079] Table 1

[0080] According to Table 1, each embodiment shows a higher average germination rate and a higher germination uniformity compared to Comparative Examples 1 and 2, indicating that the coated improved seed solution provided by the present application can significantly improve the germination rate and germination uniformity of Vallisneria seeds, and has good practical application prospects. The possible reason is that in Comparative Example 1, only the seeds were dried after activation treatment with gibberellins and directly sown, lacking substrate simulation and shell coating, resulting in a lack of stable implantation carriers in the water environment, and being affected by hydrodynamic disturbances and environmental stress, resulting in a low germination rate and a discrete germination process. Although the problem of the low strength and easy cracking of the seed pellets directly coated with bottom soil in Comparative Example 2 can be improved by adding gypsum, the layered coating structure is not constructed, and the coating method is a mixed type pellet rolling method, the structure is uneven, and the infiltration control is insufficient, resulting in a low germination rate and a low germination uniformity performance compared to the embodiment.

[0081] According to Examples 1 and 2, compared with Example 1 in which ammonium bicarbonate was added, Example 2 in which ammonium bicarbonate was not added had a slight decrease in germination rate and germination uniformity, indicating that the introduction of ammonium bicarbonate can accelerate the water penetration and material exchange process through decomposition, thereby improving the germination rate and germination uniformity.

[0082] According to Examples 1, 3 to 6, when sodium alginate and polyvinyl alcohol were simultaneously introduced into the gypsum slurry (Examples 1, 4, and 5), the germination rate and germination uniformity were better than when sodium alginate (Example 3) or polyvinyl alcohol (Example 6) was added alone. This indicates that the synergistic effect of the two hydrophilic polymers in the shell structure is stronger, which can more effectively regulate the moisture absorption and sustained release properties of the shell, while reducing the influence of external interference, thereby increasing the germination rate and germination uniformity. Furthermore, when the ratio of sodium alginate to polyvinyl alcohol is 1:2 (Example 1), the germination rate and germination uniformity are the highest.

[0083] According to Examples 1 and 7, even the gypsum slurry without the addition of mannitol (Example 7) also has a certain coating effect and lifting effect, but compared with the shell layer with the co-addition of mannitol in Example 1, the germination uniformity is slightly lower and the germination start time is slightly delayed, indicating that the introduction of mannitol helps to maintain appropriate porosity and moisture regulation ability in the shell layer, thereby making the germination rate and germination uniformity higher.

[0084] According to Examples 1 and 8, although the gypsum slurry G without adding any hydrophilic polymer can form a shell, the germination rate and uniformity are lower than those in Example 1, indicating that the hydrophilic polymer plays an important role in maintaining the flexibility of the shell and regulating the moisture absorption rate in the shell structure. Using only gypsum as the coating material may cause the shell to absorb water quickly and soften, and cannot effectively achieve slow release and stable germination. This shows that the introduction of sodium alginate and polyvinyl alcohol can further improve the germination rate and germination uniformity.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for improving the germination rate of Vallisneria seeds, characterized in that: The following steps are involved: S1: activating the Vallisneria seeds with growth hormone to activate the Vallisneria seeds from a dormant state, thereby obtaining pretreated Vallisneria seeds; S2: mixing the pretreated Vallisneria seeds, bottom soil and water to obtain a slurry, and then rolling the slurry into pellets to obtain mud pellets containing Vallisneria seeds; S3: coating the mud balls with gypsum slurry to obtain improved Vallisneria seeds.

2. The method according to claim 1, wherein step S1 comprises: The Vallisneria seeds were soaked in a 140-160 mg / L gibberellin aqueous solution for 20-30 hours and then air-dried to obtain pretreated Vallisneria seeds.

3. The method according to claim 1, characterized in that The step S2 comprises: 1000 parts of bottom soil, 30-50 parts of pretreated Vallisneria seeds and water were mixed to obtain mud with a moisture content of 35-40%, and the mud was pelletized to obtain mud pellets containing Vallisneria seeds with a diameter of 4-6 mm.

4. The method according to claim 3, characterized in that The step S2 comprises: 1000 parts of bottom soil, 30-50 parts of pretreated Vallisneria seeds, 5-15 parts of ammonium bicarbonate and water were mixed to obtain mud with a water content of 35-40%, and the mud was pelletized to obtain mud balls containing Vallisneria seeds with a diameter of 4-6 mm.

5. The method according to claim 1, wherein The step S3 comprises: 100 parts of gypsum powder, 4 to 8 parts of hydrophilic polymer and water are mixed to obtain a gypsum slurry with a moisture content of 55% to 65%, and the mud balls are coated with the gypsum slurry to obtain improved Vallisneria seeds with a diameter of 5 to 7 mm; wherein the hydrophilic polymer includes sodium alginate and polyvinyl alcohol, and the mass ratio of the sodium alginate to the polyvinyl alcohol is 1:1.5 to 2.

5.

6. The method according to claim 5, characterized in that The step S3 comprises: 100 parts of gypsum powder, 4 to 8 parts of hydrophilic polymer, 1 to 3 parts of mannitol and water are mixed to obtain gypsum slurry with a moisture content of 55% to 65%, and the mud balls are coated with the gypsum slurry to obtain improved Vallisneria seeds with a diameter of 5 to 7 mm.

7. The method according to claim 1, characterized in that The following steps are also included: S4: placing the improved Vallisneria seeds in a culture vessel and culturing them in a light incubator to obtain Vallisneria seedlings; wherein the culture vessel comprises bottom soil and water.

8. The method according to claim 7, characterized in that In the step S4: The thickness of the bottom soil in the culture vessel is 3-4 cm, and the water depth is 6-7 cm.

9. The method according to claim 7, characterized in that In the step S4: The culture conditions in the light incubator include: a temperature of 23-27° C., a light intensity of 1500 lx, and a photoperiod of 12 hours of light and 12 hours of darkness.

10. The method according to any one of claims 1 to 9, characterized in that The bottom soil has a TN content of 4-6 mg / g, a TP content of 3-5 mg / g, and a TC content of 3 wt%-5 wt%.

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