A device and method for collecting seedlings of *Porphyra yezoensis* spores.

Abstract

This invention relates to the field of artificial cultivation technology of *Porphyra yezoensis*, specifically to a *Porphyra yezoensis* conchospore collection device and a method for collecting seedlings using the device. The collection device includes a seedling tank, an aeration device, a support rod, and a net bag. The aeration device is located at the bottom of the seedling tank, with a first air outlet at its top. A gas flow valve and an air pump are sequentially connected to the outside of the seedling tank. The support rod is erected at the top of the seedling tank, and a net bag is suspended from the support rod. The net bag contains seashells with attached filamentous structures. The mesh size of the net bag is smaller than the size of the seashells, and the net bag is white near the mesh opening. The position of the first air outlet of the aeration device corresponds to the position where the net bag is suspended.

Description

Technical Field

[0001] This invention belongs to the field of genetic breeding technology, specifically relating to a device and method for collecting seedlings of *Porphyra yezoensis* spores. Background Technology

[0002] *Porphyra yezoensis* is one of the most commercially valuable species in the *Porphyra* genus, widely cultivated in coastal areas south of the Yangtze River in my country. The life cycle of *Porphyra yezoensis* consists of a microscopic shell-like filamentous stage (sporophyte) and a macroscopic thallus stage (gametophyte). Mature thallus releases carpospores, which attach to the calcareous shell and continue to germinate and grow into shell-like filaments. These filaments further develop into sporangioses, which release conchospores upon maturity. The conchospores attach to suitable substrates such as netting, and through cultivation management, eventually develop into edible thallus.

[0003] The release pattern of conchospores is not fixed. Some conchospores have a clear release peak within a specific time period, such as around 10 am, when they are released in large quantities; while others do not have a clear release peak and may be released at any time from 7 am to 1 pm. After the released conchospores attach to a suitable substrate (such as a net curtain), they gradually grow into seedlings through subsequent cultivation and management, and eventually develop into harvestable thallus.

[0004] Because conchospores sink due to gravity, excessive deposition at the bottom of water bodies for extended periods can impede water exchange, thus affecting their viability. This significantly reduces the quantity and quality of conchospores attached to the webbing, negatively impacting the yield and quality of the *Porphyra yezoensis* foliage. Therefore, conchospore collection has become a crucial step in *Porphyra yezoensis* production and a key factor determining yield and quality.

[0005] Since the initial success of artificial propagation of *Porphyra yezoensis* in the 1960s, people have gradually summarized a set of technical measures covering all aspects of production. In the traditional seed collection process, because the gravity of the *Porphyra yezoensis* spores is greater than their buoyancy, they easily sink naturally. Therefore, the traditional method of collecting *Porphyra yezoensis* spores involves placing shells with mature filamentous structures scattered above a net in a seedling pond filled with seawater. Figure 2 After the shell filaments release conchospores, the conchospores are evenly distributed in the collection water by artificial water splashing, thus completing the indoor fabric dyeing method for seed collection. With the advancement of technology, artificial water splashing has gradually been replaced by water pump flushing. Figure 3 This improved operational efficiency. Based on the traditional indoor dyeing method for seedling collection, a waterwheel-style seedling collection technique was further developed. Figure 4This method utilizes a large roller wound around a net curtain, driven by an electric motor. The roller is placed on a pool below containing seashell filaments. The conchospores released by the filaments float in the water, while the net curtain, submerged in the water, absorbs the conchospores. Once the conchospore density on the seed curtain meets the requirements, the net curtain is removed, and seed collection is complete. To reduce manual handling during the transportation of seashell filaments, a seed collection method based on cultivation areas or docks has also been developed. This method uses a seaweed handling vessel in the sea area, with waterproof plastic sheeting or tarpaulin laid inside for direct fabric-based seed collection. Figure 5 However, due to the difficulty in conducting microscopic detection during seed collection in the sea area, precise seed collection is not possible, often resulting in excessive attachment of conidia and waste of seedlings.

[0006] However, the aforementioned traditional and optimized methods for collecting *Porphyra yezoensis* seedlings still have many shortcomings, mainly related to the uncertainty of the release time and amount of conidia and their vertical settling characteristics. Since conidia are released almost vertically, manual watering or pumping cannot effectively and promptly distribute them evenly in the water, failing to meet the requirement of uniform netting. Furthermore, the conidia are not accurately counted before netting, making precise attachment impossible and resulting in difficulty controlling the attachment density, affecting subsequent cultivation results. Pumping may cause water quality instability due to heat generation, and drainage is usually concentrated in one direction, with the inlet often fixed during operation, making it difficult to ensure uniform flow throughout the water body. This uneven flow often leads to excessive deposition of conidia at the bottom or in localized areas, resulting in prolonged residence time and affecting conidia viability. In addition, contamination from external substances caused by manual entry into the seedling collection pond can also lead to water quality changes. Simultaneously, conidia easily adhere to workers' trousers, shoes, and other items, causing conidia loss and further affecting the quantity and quality of conidia attached to the netting. These problems not only limit the efficient collection of conchospores, but also adversely affect the yield and quality of Porphyra yezoensis foliage, becoming a major bottleneck for the industry's development. Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the present invention provides a device and method for collecting seedlings of *Porphyra yezoensis* spores, thereby overcoming the deficiencies of the prior art.

[0008] This invention first provides a seedling collection device for Porphyra yezoensis spores, which includes a seedling pool, an air-filling device, a support rod, and a net bag;

[0009] The inflation device is installed at the bottom of the seedling pool, and a first air outlet is opened at its top. The inflation device is connected in sequence to a gas flow valve and an air pump outside the seedling pool.

[0010] The support rod is erected on the top of the seedling pond, and a net bag is suspended on the support rod. The net bag contains shells with attached shell filaments. The size of the mesh of the net bag is smaller than the size of the shells. The color of the net bag is white near the opening.

[0011] The first air outlet of the inflation device is positioned corresponding to the position where the net bag is suspended.

[0012] Preferably, the inflation device is an inflation pipe, which is arranged in a serpentine pattern at the bottom of the seedling pool.

[0013] Furthermore, a second air outlet is provided on each of the two sides of the inflation pipe.

[0014] The present invention also provides a method for collecting seedlings of *Porphyra yezoensis* spores, wherein the method is to collect seedlings using the above-mentioned seedling collection device;

[0015] More specifically, the seedling collection method includes the following steps:

[0016] S1 Add appropriate seawater to the seedling pond, start the air pump, and adjust the gas flow valve to ensure that the air from the first air outlet can reach the water surface; place shells with cultivated shell filaments in each net bag, and hang the net bags on the support rods at intervals. Place the support rods with the net bags hanging on the top of the seedling pond so that the shells in the net bags are completely submerged in seawater. The hanging position of the net bags corresponds to the position of the first air outlet of the air inflator, and the white part of the net bag is fully or partially exposed above the water surface.

[0017] S2 When observing the accumulation of a large number of purplish-red conidia in the white part of the net bag, the peak of conidia release is determined.

[0018] S3 then counted the number of conchospores in the water;

[0019] After counting in step S3, when the number of spores in the water reaches the expected value, lift the net bag or place the net bag to one side and immerse the net curtain in seawater to collect the spores.

[0020] Furthermore, in step S1, the air inflation reaching the water surface means that by controlling the gas flow rate and volume, small bubbles can appear on the water surface, causing a ripple of about 1 cm on the water surface. It is necessary to frequently check the size and uniformity of the bubbles and adjust the air volume in a timely manner.

[0021] Furthermore, Alternating Monoclonal bacteria (Alternating Monoclonal bacteria) were added to the seawater. Alteromonas The bacterial preparation of *S. sp. MS* strain, wherein *Alternaria alternifolia* (sp. MS) Alteromonas The strain (sp. MS) was deposited on November 21, 2024, at the China Center for Type Culture Collection, Wuhan University, Wuhan, China, with accession number CCTCC NO: M 20242609.

[0022] The beneficial effects of this invention are as follows:

[0023] First, it effectively improves the uniform distribution of conchospores in the seed collection pond, reduces the chance of conchospores settling at the bottom, and, combined with timely counting of conchospores after the peak release period, achieves uniform netting and precise seedling attachment.

[0024] Secondly, by using an aeration device instead of a water pump for flushing, vertical water circulation is achieved, reducing the chance of conidia settling at the bottom and overcoming the heat generated by water pump flushing and the single horizontal flow. On the other hand, sufficient oxygen is provided, resulting in good conidia germination and strong vitality, which helps the conidia adhere firmly after being attached to the net, greatly increasing the quality of conidia release and germination effect.

[0025] Third, by setting up net bags and support structures, operators are prevented from entering the seed collection pond, which could affect water quality and cause loss of spores.

[0026] Fourth, Alternating Monoclonal bacteria ( Alteromonas sp. MS has an inhibitory mechanism against halophilic bacteria that cause filamentous yellow spot disease in laver. Alternating monoclonal bacteria may inhibit the growth of halophilic bacteria by secreting antibiotics, enzymes or other metabolites.

[0027] Fifth, Alternating Monoclonal bacteria ( Alteromonas sp. MS can promote the maturation of conchospores, which can facilitate concentrated harvesting during the collection of seaweed seedlings, improve work efficiency, and minimize the possibility of immature or aborted conchospores. Attached Figure Description

[0028] Figure 1 This is a structural diagram of the seedling collection device;

[0029] Figure 2 It is a manual watering method for collecting seedlings using a dyeing cloth method;

[0030] Figure 3 It is a dyeing-type seedling collection water pump flushing mode;

[0031] Figure 4 It is a waterwheel-style seedling collection method;

[0032] Figure 5 It is a seaweed harvesting method that utilizes seaweed handling vessels in the sea area;

[0033] Figure 6 It is the antibacterial effect of the tested strain on pathogenic halophilic bacteria. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0035] Example 1

[0036] Figure 1 As shown, a device for collecting spores of *Porphyra yezoensis* includes a seedling pool 1, an aeration device, support rods 3, and a net bag 4. The seedling pool 1 is 10×4×1m in size (length×width×depth), and is filled with seawater 6 at a depth of 0.6m.

[0037] The inflation device uses an inflation pipe 2, which extends in a serpentine shape along the long side of the seedling tank at the bottom. Adjacent inflation pipes are spaced 80cm apart. A first air outlet 2-1 is located at every 80cm interval at the top of the inflation pipe 2 along the short side of the tank. A gas flow valve 8 and an air pump 7 are sequentially connected to the inflation pipe 2 outside the seedling tank. Alternatively, an air stone can be used for inflation, with one air stone placed at every 80cm interval at the bottom of the seedling tank 1.

[0038] The support poles 3 are preferably made of moso bamboo, with a diameter of about 10cm and a length of 4 meters, totaling 12 poles. A net bag 4, 1m long and 60cm in diameter, is suspended every 80cm along each bamboo pole. Each net bag 4 contains a seashell 5 containing cultivated shell filaments, and the mesh size of the net bag 4 is smaller than the size of the seashell 5. The bamboo poles with the net bags 4 are arranged at 80cm intervals along the long side of the seedling pond 1 at its top. The seashells 5 inside the net bags are completely submerged in seawater 6, and the suspension position of the net bags 4 corresponds to the location of the first air outlet 2-1 of the inflation device. The net bags 4 are made of polyethylene, and the color of the net bag 4 near the water surface is white. This seedling pond 1 can hold 120 mu (approximately 8 hectares) of net bags 4 containing shell filaments.

[0039] Example 2

[0040] The aeration device uses an aeration pipe 2, which extends in a serpentine shape along the long side of the seedling tank 1 at the bottom. Adjacent aeration pipes are spaced 80cm apart. A first air outlet 2-1 is positioned at 80cm intervals along the top of the aeration pipe 2 along the short side of the tank. Second air outlets 2-2 are positioned on both sides of the aeration pipe between adjacent first air outlets 2-1. A gas flow valve 8 and an air pump 7 are sequentially connected to the outside of the seedling tank via the aeration pipe 2. The placement of the first air outlets 2-1 and second air outlets 2-2 creates a circulating airflow in the water, stimulating sporangium formation and reducing conchospore deposition after release.

[0041] Example 3

[0042] A method for collecting seedlings of *Porphyra yezoensis* spores, using the seedling collection device described in Example 1 or Example 2, includes the following steps:

[0043] S1 Adds seawater 6 to the seedling pond 1 to a depth of 0.6m, starts the air pump 7, and adjusts the gas flow valve 8 to ensure that the air from the first air outlet 2-1 can reach the water surface. Place shells 5 containing filamentous shells in each net bag 4. Hang the net bags 4 on the support rods 3 at intervals of 0.8m. Arrange the support rods 3 with the net bags hanging at intervals of 0.8m along the length of the pond at the top of the seedling pond 1 so that the shells in the net bags are completely submerged in the seawater 6, and the white part of the net bags is fully or partially exposed above the water surface. The hanging position of the net bags 4 corresponds to the position of the first air outlet 2-1 at the top of the air inflator.

[0044] S2 When observing the accumulation of a large number of purplish-red conidia in the white part of the net bag, the peak of conidia release is determined.

[0045] S3 then counted the number of conchospores in the water;

[0046] After counting in step S3, when the number of conchospores in the water reaches the expected value, lift the net bag 4 by lifting the support rod, or place the net bag 4 on one side, and immerse the net curtain in seawater 6 to collect seedlings according to the requirement of 200-500 million conchospores / acre.

[0047] S5 places the net bag 4 containing the shell 5 back above the net curtain, and the shell filaments continue to release conchospores, which can continue to attach to the net curtain.

[0048] In step S1, the aeration can reach the water surface, which means that by controlling the gas flow rate and flow rate, small bubbles can appear on the liquid surface, causing the liquid surface to fluctuate by about 1 cm. It is also necessary to frequently check the size and uniformity of the bubbles and make timely adjustments.

[0049] Each mesh bag 4 contains 350 pairs of scallop shells cultured with shell filaments or 1500 clam shells cultured with shell filaments.

[0050] Example 4: Antibacterial zone experiment

[0051] S1 strain culture: Alternating Monoclonal strain ( Alteromonas After activation by sp. MS, the culture medium was inoculated into 2216E liquid medium and cultured with shaking at 25°C for 24 hours. The culture was then carried out at 150 rpm until the OD value reached 0.19. The supernatant (containing metabolites) was collected by centrifugation.

[0052] Among them, Alternaria ( Alteromonas The strain (sp. MS) was screened from laver by the inventors and deposited on November 21, 2024, at the China Center for Type Culture Collection, Wuhan University, Wuhan, China, with accession number CCTCCNO: M 20242609.

[0053] After activating the halophilic bacteria that cause filamentous yellow spot disease of laver, the bacteria were inoculated into 2216E liquid medium and cultured with shaking at 25°C for 24 hours until the logarithmic growth phase.

[0054] S2 involves evenly spreading halophilic bacteria on an agar plate and immersing sterile filter paper discs in Alternating Monotrophic Bacteria (Alternating Monotrophic Bacteria). Alteromonas The filter paper was placed in the supernatant of sp. MS and then placed on an agar plate, with three replicates. Filter paper was soaked in sterile culture medium as a control group.

[0055] S3 was cultured at 25℃ for 24-48 hours, and the formation and diameter of the inhibition zone were observed.

[0056] Experimental results are as follows Figure 6 As shown: In the three experimental groups, filter paper discs 1-3 formed obvious inhibition zones around their surfaces, with an average diameter of 11.5 mm. No inhibition zone was formed in the control group 4.

[0057] Example 5: Co-culture Experiment

[0058] S1 strain culture: Same as in Example 4.

[0059] S2 mixes Alternaria alterniflora and halophilic bacteria in a 1:1 ratio and inoculates them into 2216E liquid culture medium.

[0060] S3 sets up a control group: only saline bacteria are inoculated.

[0061] S4 was cultured at 25℃ for 48 hours, and samples were taken periodically. The growth of pathogenic bacteria (OD600 value) was determined by spectrophotometer.

[0062] The experimental results are shown in Table 1: The growth of pathogenic bacteria in the experimental group was significantly inhibited, and the OD600 value was reduced by about 65% compared with the control group. The halophilic bacteria in the control group grew normally, and the OD600 value increased over time.

[0063] Table 1: Growth of halophilic bacteria (OD600 value)

[0064]

[0065] Based on the above inhibition zone experiment and co-culture experiment, it can be concluded that Alternaria alterniflora (… Alteromonas sp. MS has an inhibitory mechanism against halophilic bacteria that cause macular degeneration. Alternating monoclonal bacteria may inhibit the growth of halophilic bacteria by secreting antibiotics, enzymes or other metabolites.

[0066] Example 6

[0067] A method for collecting seedlings of *Porphyra yezoensis* spores, using the seedling collection device described in Example 1 or Example 2, includes the following steps:

[0068] Preparation of S1 bacterial preparation

[0069] Alternating Monoclonal strains ( Alteromonas After activation by sp. MS, 2216E medium was used, with an inoculation density of 35 ml of medium and 2.5 μl of bacterial suspension added. The medium was incubated at 25℃ and 150 rpm until the OD value reached 0.19. The supernatant was then collected by centrifugation.

[0070] Alternating Monoclonal bacteria ( Alteromonas The strain (sp. MS) was deposited on November 21, 2024, at the China Center for Type Culture Collection, Wuhan University, Wuhan, China, with accession number CCTCC NO: M 20242609.

[0071] S2. Add seawater 6 to the seedling pond 1, with a water depth of 0.6m. Add the bacterial preparation prepared in step S1 to the seawater 6. The concentration of the bacterial preparation is 1:1000.

[0072] S3 starts the air pump 7 and adjusts the gas flow valve 8 to ensure that the air from the first air outlet 2-1 can reach the water surface. Place shells 5 containing filamentous shells in each net bag 4. Hang the net bags 4 on the support rods 3 at intervals of 0.8m. Arrange the support rods 3 with the net bags hanging at intervals of 0.8m along the length of the pond at the top of the seedling pond 1 so that the shells in the net bags 4 are completely submerged in the seawater 6, and the white part of the net bags is fully or partially exposed above the water surface. The hanging position of the net bags 4 corresponds to the position of the first air outlet 2-1 at the top of the air inflator.

[0073] S4 When observing the accumulation of a large number of purplish-red conidia in the white part of the net bag, the peak of conidia release is determined.

[0074] S5 then counted the number of conchospores in the water.

[0075] After counting in step S3, when the number of conchospores in the water reaches the expected value, lift the net bag 4 by raising the support rod, or place the net bag 4 on one side, and immerse the net curtain in seawater to collect seedlings according to the requirement of 200-500 million conchospores / acre.

[0076] S7 places the net bag 4 containing the shells back above the net curtain, and the shell filaments continue to release conchospores, which can continue to attach to the net curtain.

[0077] Example 7

[0078] A method for collecting seedlings of *Porphyra yezoensis* spores, using the seedling collection device described in Example 1 or Example 2, includes the following steps:

[0079] Preparation of S1 bacterial preparation

[0080] Alternating Monoclonal strains ( Alteromonas After activation by sp. MS, 2216E medium was used, with an inoculation density of 35 ml of medium and 2.5 μl of bacterial suspension added. The medium was incubated at 25℃ and 150 rpm until the OD value reached 0.19. The supernatant was then collected by centrifugation.

[0081] S2. Add seawater 6 to the seedling pond 1 at a depth of 0.6m, and add the bacterial preparation prepared in step S1 to the seawater 6. The concentration of the bacterial preparation is 1:2500.

[0082] S3 starts the air pump 7 and adjusts the gas flow valve 8 to ensure that the air from the first air outlet 2-1 can reach the water surface. Place shells 5 containing cultivated shell filaments in each net bag 4. Hang the net bags 4 on the support rod 3 at intervals of 0.8m. Arrange the support rods 3 with the net bags hanging at intervals of 0.8m along the length of the pond at the top of the seedling pond 1 so that the shell filaments in the net bags are completely submerged in the seawater 6, and the white part of the net bag is fully or partially exposed above the water surface. The hanging position of the net bag 4 corresponds to the position of the first air outlet 2-1 at the top of the air inflator.

[0083] S4 When observing the accumulation of a large number of purplish-red conidia in the white part of the net bag, the peak of conidia release is determined.

[0084] S5 then counted the number of conchospores in the water.

[0085] After counting in step S3, when the number of conchospores in the water reaches the expected value, lift the net bag 4 by raising the support rod, or place the net bag 4 on one side, and immerse the net curtain in seawater to collect seedlings according to the requirement of 200-500 million conchospores / acre.

[0086] Example 8

[0087] A method for collecting seedlings of *Porphyra yezoensis* spores, using the seedling collection device described in Example 1 or Example 2, includes the following steps:

[0088] Preparation of S1 bacterial preparation

[0089] Alternating Monoclonal strains ( Alteromonas After activation by sp. MS, 2216E medium was used, with an inoculation density of 35 ml of medium and 2.5 μl of bacterial suspension added. The medium was incubated at 25℃ and 150 rpm until the OD value reached 0.19. The supernatant was then collected by centrifugation.

[0090] S2. Add seawater 6 to the seedling pond 1 at a depth of 0.6m, and add the bacterial preparation prepared in step S1 to the seawater 6. The concentration of the bacterial preparation is 1:4000.

[0091] S3 starts the air pump 7 and adjusts the gas flow valve 8 to ensure that the air from the first air outlet 2-1 can reach the water surface. Place shells 5 containing cultivated shell filaments in each net bag 4. Hang the net bags 4 on the support rods 3 at intervals of 0.8m. Arrange the support rods 3 with the net bags 4 hanging at intervals of 0.8m along the length of the pond at the top of the seedling pond 1 so that the shell filaments in the net bags 4 are completely submerged in the seawater 6, and the white part of the net bags is fully or partially exposed above the water surface. The hanging position of the net bags 4 corresponds to the position of the first air outlet 2-1 at the top of the air inflator.

[0092] S4 When observing the accumulation of a large number of purplish-red conidia in the white part of the net bag, the peak of conidia release is determined.

[0093] S5 then counted the number of conchospores in the water.

[0094] After counting in step S3, when the number of conchospores in the water reaches the expected value, lift the net bag 4 by raising the support rod, or place the net bag 4 on one side, and immerse the net curtain in seawater to collect seedlings according to the requirement of 200-500 million conchospores / acre.

[0095] The maturity rate of Porphyra yezoensis spores and the frequency of harvesting on the same day in Examples 6, 7 and 8 were compared with those without bacterial solution as a control.

[0096] Table 2: Comparison of Laver spore maturity rate and harvesting frequency between those without and with inoculant.

[0097]

[0098] Therefore, it can be concluded that Alternaria alternifolia (… Alteromonas sp. MS can, on the one hand, promote the maturation of conchospores, concentrate harvesting, improve work efficiency, and minimize the possibility of immature or aborted conchospores; on the other hand, it has an inhibitory effect on the halophilic bacteria that cause yellow spot disease.

[0099] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

Claims

1. A method for collecting seedlings of *Porphyra yezoensis* spores, characterized in that, Includes the following steps: S1. Add appropriate seawater to the seedling tank and inflate it through the first air outlet at the bottom of the seedling tank to ensure that the air from the first air outlet can reach the water surface; place shells with cultivated shell filaments in each net bag. The net bags are white near the net opening. Hang the net bags on the support rods at intervals. Place the support rods with the net bags hanging on the top of the seedling tank so that the shells in the net bags are completely submerged in seawater and the white part of the net bags is fully or partially exposed above the water surface. The hanging position of the net bags corresponds to the position of the first air outlet. S2 When observing the accumulation of a large number of purplish-red conidia in the white part of the net bag, the peak of conidia release is determined. S3 then counted the number of conchospores in the water; S4 After counting in step S3, when the number of spores in the water reaches the expected value, lift the net bag or place the net bag to one side and immerse the net curtain in seawater to collect seedlings. The seawater contains Alternaria alternifolia (… Alteromonas Preparations of strains (sp. MS); The Alternating Monoclonal bacteria ( Alteromonas The strain (sp. MS) was deposited on November 21, 2024, at the China Center for Type Culture Collection, Wuhan University, Wuhan, China, with accession number CCTCC NO: M 20242609.

2. The method for collecting seedlings of *Porphyra yezoensis* spores according to claim 1, characterized in that, The Alternating Monoclonal bacteria ( Alteromonas The preparation method of bacterial preparation of *Sp. MS* strain is as follows: *Alternaria alternifolia* (sp. MS) is prepared by adding... Alteromonas After activation of the strain (sp. MS), 2216E medium was used, with an inoculation density of 35 ml of medium and 2.5 μl of bacterial suspension added. The culture was carried out at 25℃ and 150 rpm until the OD value reached 0.

19. The supernatant was then collected by centrifugation.

3. The method for collecting seedlings of *Porphyra yezoensis* spores according to claim 1, characterized in that: In step S1, the inflation is able to reach the water surface, which means that the gas flow rate and flow rate are controlled to ensure that small bubbles appear on the water surface, causing the water surface to fluctuate by about 1 cm. It is necessary to check the size and uniformity of the bubbles frequently and adjust the gas volume in a timely manner.

4. The method for collecting seedlings of *Porphyra yezoensis* spores according to claim 1, characterized in that: In step S4, after the net curtain is immersed in seawater to collect seedlings, the net bag containing the shells is placed back on top of the net curtain.

5. The method for collecting seedlings of *Porphyra yezoensis* spores according to claim 1, characterized in that: The first air outlet is arranged in a serpentine pattern at the bottom of the seedling pool via an air inflator.

6. The method for collecting seedlings of *Porphyra yezoensis* spores according to claim 5, characterized in that: The inflation pipe has a second air outlet on each of its two sides.

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