Method for culturing analipus japonicus holdfasts

Abstract

To provide a method for culturing Analipus japonicus holdfasts in a growth state suitable for the germination of upright bodies.SOLUTION: A method for culturing Analipus japonicus holdfasts includes the step of irradiating Analipus japonicus holdfasts with light within the wavelength region of 500 nm or more and less than 600 nm.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for culturing the appressorium of Acanthurus japonica. [Background technology]

[0002] Matsumo is a seaweed that grows mainly along the northwestern and northeastern Pacific coasts of Japan and is prized locally as a luxury food. In addition to being eaten as is, Matsumo is used in a variety of foods, such as parboiled or dried Matsumo, and demand is growing due to its rich nutritional content and good flavor and texture. Therefore, in order to ensure a stable supply of Matsumo, it is desirable to establish technology for cultivating Matsumo.

[0003] As a technique for cultivating Matsumo, a technique for cultivating zoospores and zygotes from natural seedlings by attaching them to twisted threads (Non-Patent Documents 1-3) has been disclosed. However, in the case of natural seedlings, the period during which seedlings such as zoospores and zygotes can be harvested is limited, and it is not always possible to obtain seedlings of stable quality and quantity. In addition, in the growth process of Matsumo, the seedlings go through a stage where an upright body germinates, but in order for the upright body to germinate, the seedlings must be in good growth condition, otherwise the upright body will not germinate easily, and even if the upright body germinates, there is a risk that it will die during the cultivation stage. Furthermore, the timing of germination is also important, and if the germination of the upright body progresses too much during the growth of the seedlings, it is sufficient to use them for cultivation immediately, but if the seedlings are not used for cultivation for a while and the seedlings are continued to be cultivated while the upright body is still in a state of advanced germination, there is also a problem that the seedlings will die. There is a need for a technology for culturing the appressoria of D. japonica in order to obtain seedlings in good condition that can be used in a timely manner for D. japonica culture. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Shinji Tsutsumi, "Experiment on the cultivation of seaweed using twisted thread," Fisheries and Aquaculture, Vol. 30, No. 2, pp. 126-130 (1982) [Non-Patent Document 2] Shinji Tsutsumi, "Experiment for cultivating Matsumo using twisted thread-II," Fisheries and Aquaculture, Vol. 31, No. 4, pp. 196-199 (1984) [Non-Patent Document 3] Shinji Tsutsumi, "Experiment for cultivating seaweed using twisted thread-III," Fisheries and Aquaculture, Vol. 33, No. 2, pp. 72-75 (1985) Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a method for culturing appressoria of Atractylodes macrocarpa that are in a good growth condition suitable for germination of upright bodies. [Means for solving the problem]

[0006] As a result of intensive research into the above-mentioned problems, the inventors discovered that by irradiating the appressoria of Drosophila with light in a specific wavelength range, it is possible to cultivate Drosophila appressoria in a good state of growth that are capable of germinating upright bodies in a timely manner, and further that these can also be used as seedlings for aquaculture. Based on this knowledge, they have developed the present invention.

[0007] That is, the present invention includes a method for culturing appressoria of Daikon radish, which comprises a step of irradiating the appressoria of Daikon radish with light in the wavelength range of 500 nm or more and less than 600 nm. Effect of the Invention

[0008] The method for culturing appressoria of D. moniliforme of the present invention increases the mass of the appressoria of D. moniliforme, and allows the production of appressoria of D. moniliforme in a good state of growth that can germinate upright bodies at the appropriate time. That is, according to the present invention, the germination of upright bodies is inhibited during growth, and thus D. moniliforme that maintain a good state of growth can be obtained. The obtained appressoria can be stored for a while, and upright bodies can also be germinated from the appressoria at the appropriate time, making them useful as seedlings for aquaculture. [Brief description of the drawings]

[0009] [Figure 1]FIG. 1 shows the life cycle of Drosophila arbutus. [Diagram 2] FIG. 2 shows the subcycles of the life cycle of Acanthurus arbutus. [Diagram 3] FIG. 3 is a graph showing the change in mass (g) of the appressorium of D. arbutifolia in culture test 1 of the appressorium of D. arbutifolia. [Figure 4] FIG. 4 is a graph showing the relative growth rate (RGR) of the appressorium of D. arbutifolia in culture test 1 of the appressorium of D. arbutifolia. [Diagram 5] FIG. 5 is a graph showing the change in mass (g) of the appressorium of D. arbutifolia in culture test 2 of the appressorium of D. arbutifolia. [Figure 6] FIG. 6 is a graph showing the relative growth rate (RGR) of the appressorium of D. arbutifolia in culture test 2 of the appressorium of D. arbutifolia. [Figure 7] FIG. 7 is a graph showing the change in mass (g) of the appressorium of D. arbutifolia in culture test 3 of the appressorium of D. arbutifolia. [Figure 8] FIG. 8 is a graph showing the relative growth rate (RGR) of the appressorium of D. arbutifolia in culture test 3 of the appressorium of D. arbutifolia. [Figure 9] FIG. 9 is a graph showing the change in mass (g) of the appressorium of D. arbutifolia in culture test 4 of the appressorium of D. arbutifolia. [Figure 10] FIG. 10 is a graph showing the relative growth rate (RGR) of the appressorium of D. arbutifolia in culture test 4 of the appressorium of D. arbutifolia. [Figure 11] FIG. 11 is a photograph showing the growth state of appressoria after 21 days of culture in culture test 4 of appressoria of Drosophila japonica. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In the present invention, "Analipa" refers to Analipus japonicus, which belongs to the genus Analipa, family Ralfsiaceae, order Ralfsiales, class Phaeophyceae.

[0011] In the present invention, "appressorium" refers to the disk-shaped growth of female or male gametes of Daikon radish, the disk-shaped growth of a zygote developed by the fusion of these gametes, or the disk-shaped growth of Daikon radish zoospores. The appressorium also serves as a support that attaches to rocks and the like and supports the upright body of Daikon radish (see Daikon radish life cycle in Figure 1).

[0012] In the present invention, "germination of an upright body" refers to a state in which an assimilation thread, i.e., an upright body, is formed from the appressorium of A. japonica. The upright bodies that germinate from the appressorium of A. japonica may be formed in multiple places from the appressorium of A. japonica, and each one grows columnarly to form numerous branches, which become the main body of A. japonica. The main body of A. japonica is also called an upright branch, and is an annual that disappears in summer, whereas the appressorium is perennial. A. japonica can also exist in a form called a filamentous body that does not have an appressorium, and an upright body with an appressorium can be formed by culturing the filamentous body (see the life cycle subcycle of A. japonica in Figure 2). In the present invention, in addition to the appressorium of the upright body of A. japonica attached to rocks, etc., the appressorium of the upright body of A. japonica obtained by culturing the filamentous body can also be used.

[0013] The appressorium of Daikon radish used in the present invention is preferably a cut appressorium, since this promotes tissue regeneration from the cut surface and facilitates the growth of the appressorium of Daikon radish. The appressoria of waterweed can be cut artificially using a bladed tool such as a knife, cutter, kitchen knife, or scalpel, or a laser. It can also be cut by drifting objects on or in the sea, such as driftwood, stones, or shellfish, or by the behavior of nearby marine life. The cut appressorium refers to an appressorium having a cut surface formed when a part or a plurality of parts of the appressorium are cut, and the shape of the cut surface is not particularly limited, and may be a smooth plane or an irregular surface. The size of the appressorium of Azuma is not particularly limited, and for example, the longest part is preferably 0.5 to 20 mm, more preferably 1 to 10 mm, and even more preferably 1 to 5 mm. The shape of the appressorium of Azuma is not particularly limited, and examples thereof include rectangular parallelepiped, cylindrical, spherical, plate-like, and irregular shapes. The weight of each Azuma appressorium is not particularly limited, and for example, 0.2 to 300 mg is preferred, more preferably 0.3 to 40 mg, and even more preferably 0.3 to 20 mg. These are the cases when the weight is measured without drying. When the size and weight of Azuma are within the above range, it is preferable in that it is easy to float during cultivation and the growth of Azuma appressorium is promoted.

[0014] In the present invention, the process includes a step of irradiating light in a wavelength range of 500 nm to less than 600 nm. The light source of the light in the wavelength range of 500 nm to less than 600 nm is not particularly limited, and examples thereof include sunlight, fluorescent lamps, incandescent lamps, sodium lamps, and light derived from LEDs (light emitting diodes). However, in consideration of the ease of controlling the wavelength range of light, the lack of heat generation, and the low running costs, light derived from LEDs is preferred. In addition, when using a light source that also includes light in a wavelength range other than 500 nm to less than 600 nm, it is preferable to use a material having a shape such as a net, sheet, or film that selectively transmits light in the wavelength range of 500 nm to less than 600 nm to reduce or block light in the wavelength range other than 500 nm to less than 600 nm.

[0015] Examples of light in the wavelength range of 500 nm or more and less than 600 nm include green light, green light with a peak wavelength of 525 nm, and green LED light (peak wavelength: 525 nm + / - 10 nm, wavelength range: approximately 490 to 550 nm), with green LED light being preferred.

[0016] The light dose when irradiating with light in the wavelength range of 500 nm or more and less than 600 nm is 15 μmol / m2 / s or more is preferable, and 25 μmol / m 2 / s or more is more preferable, and 50 μmol / m 2 / s or more is more preferable, and 100 μmol / m 2 / s or more is most preferable, with the upper limit being 250 μmol / m 2 / s or less is preferable, and 200 μmol / m 2 / s or less is more preferable, and 150 μmol / m 2 / s or less is more preferable. 2 / s is preferred, and 25 to 150 μmol / m 2 / s is more preferable, and 50 to 150 μmol / m 2 / s is more preferable, and 100 to 150 μmol / m 2 / s is most preferred, but is not limited to these.

[0017] In the step of irradiating light in a wavelength range of 500 nm or more and less than 600 nm, light in a wavelength range other than 500 nm or more and less than 600 nm may be included, but it is preferable to irradiate light that does not include light in a wavelength range of 400 nm or more and less than 500 nm [e.g., blue light, blue light with a peak wavelength of 453 nm, light from a blue LED (peak wavelength: 453 nm + / - 10 nm, wavelength range: about 430 to 500 nm), etc.], and more preferably irradiate light that does not include light in a wavelength range of 600 nm or more and less than 700 nm [e.g., red light, red light with a peak wavelength of 641 nm, light from a red LED (peak wavelength: 641 nm + / - 10 nm, wavelength range: about 630 to 680 nm), etc.] and light in a wavelength range of 400 nm or more and less than 500 nm, and even more preferably irradiate only light in a wavelength range of 500 nm or more and less than 600 nm, but is not limited thereto. When light in a wavelength range other than 500 nm or more and less than 600 nm is included, it is preferable to irradiate the light by reducing the amount of light in the wavelength range other than 500 nm or more and less than 600 nm.

[0018] The culture environment for irradiating light in the wavelength range of 500 nm or more and less than 600 nm is not particularly limited as long as it is a condition under which the appressorium of Acanthus fasciatus can grow, and examples thereof include conditions in seawater or in a seawater medium (e.g., PESI medium) as described below. The seawater is not particularly limited, and may be seawater collected directly from the ocean, subterranean seawater collected from underground near the coast or from the ocean floor (e.g., continental shelf), deep ocean water collected from the deep sea, etc. Also, distilled water, tap water, etc., to which necessary mineral components (e.g., salts such as calcium, potassium, sodium, magnesium, etc.) have been added to have a composition similar to that of seawater may be used.

[0019] In the step of irradiating with light in the wavelength range of 500 nm or more and less than 600 nm, irradiation may be continuous or not continuous during culture, and irradiation may be repeated according to a daily light / dark time cycle, such as the light irradiation cycle described below, but repeated irradiation according to a daily light / dark time cycle is preferable.

[0020] The light irradiation time cycle can be, for example, a daily light / dark time cycle of 7 to 18 hours of light and 17 to 6 hours of dark in a 24-hour period (the total of the light and dark periods is 24 hours; the same applies below), preferably 8 to 16 hours of light and 16 to 8 hours of dark, more preferably 12 to 16 hours of light and 12 to 8 hours of dark, and even more preferably 14 to 16 hours of light and 10 to 8 hours of dark, but is not limited to these.

[0021] The number of days for light irradiation may be, for example, 7 days or more for the light irradiation cycle, preferably 14 days or more, and more preferably 21 days or more, but is not limited thereto. The total light irradiation time is, for example, preferably 70 hours or more, more preferably 140 hours or more, and even more preferably 210 hours or more, but is not limited thereto.

[0022] The temperature of the seawater or seawater medium used during light irradiation is, for example, preferably 10 to 30°C, more preferably 15 to 25°C, and even more preferably 20 to 22°C, but is not limited thereto.

[0023] Nutritional conditions of seawater or seawater medium are not particularly limited, but the nitrate nitrogen concentration, which is a major nutrient salt component for seaweed, is preferably 0.1 to 50 μmol / L, more preferably 0.2 to 10 μmol / L, and even more preferably 0.5 to 10 μmol / L. Phosphate phosphorus concentration is preferably 0.01 to 5 μmol / L, more preferably 0.02 to 1 μmol / L, and even more preferably 0.05 to 1 μmol / L. When using seawater, the nitrate nitrogen concentration of general seawater is usually 30 μmol / L or less, and the phosphate phosphorus concentration is often 3 μmol / L or less, so it is possible to add, for example, a nutrient salt solution for seaweed culture to the seawater. The salt concentration of seawater or seawater medium is not particularly limited, but for example, it is preferably 1.5 to 4.5 mass%, more preferably 2 to 3.5 mass%, and even more preferably 2.8 to 3.3 mass%, etc. It is preferable to replace the seawater or seawater medium with fresh water at least once every seven days.

[0024] There are no particular limitations on the method of irradiating light in the wavelength range of 500 nm or more and less than 600 nm, as long as the light is irradiated onto the appressoria of the seaweed. For example, there can be mentioned a method in which light is irradiated directly onto the surface of the seawater or the surface of the seawater medium from above the opening of a container filled with seawater or seawater medium, thereby irradiating the appressoria with light, or a method in which light is irradiated through a container filled with seawater or seawater medium that does not block light, thereby irradiating the appressoria with light.

[0025] In the present invention, the appressorium of Azuma may be pre-cultured before the step of irradiating the light having a wavelength of 500 nm or more and less than 600 nm, for the purpose of facilitating the growth of the appressorium of Azuma or for the purpose of recovering the tissue of the cut surface when a cut appressorium is used. In the pre-culture, for example, the appressorium of Azuma is placed in a container filled with the seawater or seawater medium, and cultured for preferably 10 days or more at a temperature condition of preferably 10 to 30°C, more preferably 15 to 25°C, and even more preferably 20 to 22°C. In this case, it is preferable to irradiate with white light, and the light irradiation time cycle is preferably a 10 to 14 hour light period and a 14 to 10 hour dark period in a 24-hour period, more preferably a 10 to 12 hour light period and a 14 to 12 hour dark period, and even more preferably a 12 hour light period and a 12 hour dark period. Examples of white light include sunlight, fluorescent lamps, incandescent lamps, white LEDs, and the like. It is preferable that the white light contains equal amounts of light in the wavelength ranges of 400 nm or more and less than 500 nm, 500 nm or more and less than 600 nm, and 600 nm or more and less than 700 nm, but it does not have to be equal amounts of light, and it is sufficient if the visible light rays of each wavelength contained in the light in these wavelength ranges are mixed together to appear white. The amount of white light is 15 to 200 μmol / m 2 / s is preferred, and 25 to 150 μmol / m 2 / s is more preferable, and 25 to 100 μmol / m 2 / s is more preferable, and 50 to 100 μmol / m 2 The seawater or seawater medium is preferably replaced with fresh seawater at least once a day.

[0026] As described above, by carrying out a step of irradiating the appressorium of D. moniliforme with light having a wavelength of 500 nm or more and less than 600 nm after optionally carrying out preliminary culture, the appressorium of D. moniliforme will eventually grow to a weight of preferably 0.2 to 1000 mg, more preferably 1 to 100 mg, and even more preferably 1 to 50 mg per piece. Note that these weights are measured without drying. Furthermore, the relative growth rate (RGR) represented by the following formula can be used as an index showing how well the appressorium of Daikon radish has grown from the start of culture (if preliminary culture is performed, culture start is defined as the end of preliminary culture; the same applies below) to the end of culture. The relative growth rate (RGR) is preferably greater than 0.015, more preferably 0.02 or greater, even more preferably 0.03 or greater, and may be greater than 0.015 and 0.036 or less, but is not limited to these.

[0027] Relative growth rate (RGR) = log [mass of appressoria of Azolla after the end of culture (g) / mass of appressoria of Azolla at the start of culture (g)] / number of days in culture

[0028] The appressorium of the daisy-shrimp thus obtained has a good growth condition suitable for the germination of the upright body, and the upright body can be sprouted from the appressorium of the daisy-shrimp at the appropriate time and used as a seedling for the cultivation of the daisy-shrimp. For example, the appressorium of the daisy-shrimp grown by the method of the present invention can be attached to a substrate and placed in seawater together with the substrate, but this is not limited thereto. It is preferable that the germination of the upright body from the appressorium is performed immediately before the start of the cultivation, for example, immediately before placing it in seawater. The substrate is not particularly limited, and examples thereof include polypropylene, chemical fibers made by mixing and twisting vinylon and polypropylene, and palm thread. The shape of the substrate is not particularly limited, and examples thereof include a net shape, a curtain shape, and a shape in which thread is wrapped around a frame. Examples of a method for placing the substrate to which the appressorium from which the upright body has sprouted is attached in seawater include a method of placing it in the ocean with calm waves, and a method of filling a container such as an aquarium installed on land with seawater and placing it therein. When installing, it is preferably installed at a position about 0 to 2 m below the water surface, more preferably about 0.1 to 1.5 m below the water surface, and even more preferably about 0.2 to 1.0 m below the water surface.

[0029] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these. EXAMPLES

[0030] [Preparation of appressoria of waterweed] Parts of the erect bodies of Matsumozu collected along the coast of Okirai Bay, Ofunato City, Iwate Prefecture were cultured to produce Matsumozu filaments, and the erect bodies were then re-formed from the filaments. The appressoria of the erect bodies thus formed were used for the tests. The appressoria of Matsumozu were cut into multiple irregular pieces with the longest part of each piece being 2-4.75 mm with a scalpel, and these were placed in a transparent 300 mL marine flask filled with sterilized seawater (nitrate nitrogen concentration 10 μmol / L or less, phosphate phosphorus concentration 1 μmol / L or less) and exposed to a light intensity of 50 μmol / m 2 The cells were exposed to white LED light (including equal amounts of light in the wavelength ranges of 400 nm or more and less than 500 nm, 500 nm or more and less than 600 nm, and 600 nm or more and less than 700 nm) at 400 / s so that the daily light / dark cycle was 12 hours light and 12 hours dark, and the cells were pre-cultured in an incubator (model: CN-40A; manufactured by Mitsubishi Electric Engineering Co., Ltd.) at 20°C for 10 days to obtain cut appressoria of Matsumo. Note that during the pre-culture, the sterilized seawater was changed once a day.

[0031] [Cultivation test of appressoria of Drosophila 1] Ten pieces (0.106 to 0.1219 g) of the cut appressoria of the seaweed obtained in the preliminary culture were placed in a transparent 300 mL marine flask filled with PESI medium and exposed to a light intensity of 50 μmol / m 2The plants were irradiated with green LED light at 1000 / s so that the light / dark cycle was 14 hours light and 10 hours dark, and cultured at 20°C in an incubator (model: CN-40A; manufactured by Mitsubishi Electric Engineering Co., Ltd.). After 7, 14, and 21 days from the start of culture, the mass (g) of the appressorium of the daisy was measured, and the relative growth rate (RGR) after 21 days from the start of culture was calculated based on the above formula. In addition, the number of appressorium with germinated upright bodies was confirmed after 7, 14, and 21 days from the start of culture, and the germination rate (%) of the upright bodies of the daisy was calculated using the following formula. This operation was also performed for blue LED light and red LED light, and the mass (g) of the appressorium of the daisy was measured for each and the relative growth rate (RGR) was calculated. In addition, the germination rate (%) of the upright bodies of the daisy was calculated for each. In addition, an appressorium with at least one upright part sprouting 1 mm or more from the appressorium was judged to be an “appressorium with an upright part sprouting.” The PESI medium was replaced once every 7 days.

[0032] Germination rate (%) = (number of appressoria with upright germinated bodies / number of appressoria placed in flask) × 100

[0033] Cultivation test 1 was carried out three times for green LED light, blue LED light, and red LED light, and the mass (average, g) of the appressorium of D. arbutifolia, the relative growth rate (average, g), and the germination rate (average, %) of the upright body of D. arbutifolia were determined for each.

[0034] In addition, the germination rate (average value, %) of the upright bodies of D. arbutifolia was evaluated for green LED light, blue LED light, and red LED light, and the inhibition of germination of the upright bodies of D. arbutifolia was evaluated with a symbol according to the following evaluation criteria.

[0035] <Evaluation criteria for inhibition of germination of upright bodies of waterweed> ○: The germination rate of the upright body of the moss is suppressed to less than 20%. △: The germination rate of the upright body of the moss is 20% or more but less than 40%. ×: The germination rate of the upright bodies of the moss is 40% or more.

[0036] The mass (average, g) of the appressoria of D. arbutifolia for green LED light, blue LED light, and red LED light are shown in Table 1 and Figure 3, the relative growth rates (average) are shown in Table 2 and Figure 4, and the evaluation results of germination inhibition of the upright bodies of D. arbutifolia are shown in Table 3.

[0037] [Table 1]

[0038] [Table 2]

[0039] [Table 3]

[0040] Table 1 and Figure 3 show that almost no increase in the mass of the appressorium of the seaweed was observed under red LED light, but an increase in the mass of the appressorium of the seaweed was observed under green LED light and blue LED light. Furthermore, Table 2 and Figure 4 show that the relative growth rate of the seaweed was low under red LED light, whereas the relative growth rate of the seaweed tended to be high under green LED light and blue LED light. On the other hand, as shown in Table 3, under blue LED light, the germination rate of the upright bodies of D. japonica exceeded 40% after 14 and 21 days of cultivation. This shows that blue LED light is not very suitable for the growth of D. japonica's appressoria when maintaining good growth conditions and storing them for a while to be used as seedlings for aquaculture. From the above, it was found that green LED light is suitable for growing the appressorium of D. arbutifolia while suppressing the germination of the upright body of D. arbutifolia at an undesirable stage.

[0041] [Cultivation test of appressoria of Drosophila 2] A test similar to the above Culture Test 1 was carried out, except that the daily light / dark cycle was changed to 10 hours light and 14 hours dark. The mass (average, g) of the appressoria of D. arbutifolia for green LED light, blue LED light, and red LED light are shown in Table 4 and Figure 5, the relative growth rates (average) are shown in Table 5 and Figure 6, and the evaluation results of germination inhibition of the upright body of D. arbutifolia are shown in Table 6.

[0042] [Table 4]

[0043] [Table 5]

[0044] [Table 6]

[0045] Table 4 and Figure 5 show that almost no increase in the mass of the appressorium of the seaweed was observed under red LED light, but an increase in the mass of the appressorium of the seaweed was observed under green LED light and blue LED light. Also, Table 5 and Figure 6 show that the relative growth rate of the seaweed was low under red LED light, whereas the relative growth rate of the seaweed tended to be high under green LED light and blue LED light. On the other hand, as shown in Table 6, under blue LED light, the germination rate of the upright bodies of D. japonica exceeded 40% after 14 and 21 days of cultivation. This shows that blue LED light is not very suitable for the growth of D. japonica's appressoria when maintaining good growth conditions and storing them for a while to be used as seedlings for aquaculture. From the above, it was found that green LED light is suitable for growing the appressorium of D. arbutifolia while suppressing the germination of the upright body of D. arbutifolia at an undesirable stage.

[0046] [Cultivation test of appressoria of Drosophila 3] A test similar to the above culture test 1 was carried out, except that the culture temperature was changed to 10°C. The mass (average, g) of the appressoria of D. arbutifolia for green LED light, blue LED light, and red LED light are shown in Table 7 and Figure 7, the relative growth rates (average) are shown in Table 8 and Figure 8, and the evaluation results of germination inhibition of the upright body of D. arbutifolia are shown in Table 9.

[0047] [Table 7]

[0048] [Table 8]

[0049] [Table 9]

[0050] Table 7 and Figure 7 show that almost no increase in the mass of the appressorium of the seaweed was observed under red LED light, but an increase in the mass of the appressorium of the seaweed was observed under green LED light and blue LED light. Also, Table 8 and Figure 8 show that the relative growth rate of the seaweed was low under red LED light, whereas the relative growth rate of the seaweed tended to be high under green LED light and blue LED light. On the other hand, as shown in Table 9, the germination rate of the upright bodies of D. japonica after 21 days of cultivation under blue LED light exceeded 40%. This shows that blue LED light is not very suitable for the growth of D. japonica's appressoria when maintaining good growth conditions and storing them for a while to be used as seedlings for aquaculture. From the above, it was found that green LED light is suitable for growing the appressorium of D. arbutifolia while suppressing the germination of the upright body of D. arbutifolia at an undesirable stage.

[0051] [Cultivation test of appressoria of Drosophila 4] The light dose is 100 μmol / m 2 A test similar to the above Culture Test 1 was carried out, except that the culture medium was changed to / s. The masses (average, g) of the appressoria of D. moniliforme for green LED light, blue LED light, and red LED light are shown in Table 10 and Figure 9, the relative growth rates (average) are shown in Table 11 and Figure 10, and the evaluation results of inhibition of germination of the upright bodies of D. moniliforme are shown in Table 12. Photographs of the appressoria of D. moniliforme exposed to various types of light after 21 days of cultivation are shown in Figure 11.

[0052] [Table 10]

[0053] [Table 11]

[0054] [Table 12]

[0055] From Table 10 and Figure 9, almost no increase in the mass of the appressorium of the seaweed was observed under red LED light, but an increase in the mass of the appressorium of the seaweed was observed under green LED light and blue LED light. Also, from Table 11 and Figure 10, the relative growth rate of the seaweed was low under red LED light, whereas the relative growth rate of the seaweed tended to be high under green LED light and blue LED light. On the other hand, as shown in Table 12, under blue LED light, the germination rate of the upright bodies of D. japonica exceeded 40% after 14 and 21 days of cultivation. This shows that blue LED light is not very suitable for the growth of D. japonica's appressoria when maintaining good growth conditions and storing them for a while to be used as seedlings for aquaculture. In addition, Figure 11 shows that the appressoria of the seaweed grow larger under green light than under red light. Under blue light, the appressoria of the seaweed grow, but the upright part has already germinated. From the above, it was found that green LED light is suitable for suppressing the germination of the upright body of D. japonica while promoting the growth of D. japonica's appressoria.

[0056] From the above, it was found that by irradiating the appressoria of D. arborescens with light in the wavelength range of 500 nm or more and less than 600 nm, it is possible to cultivate D. arborescens in a good growth condition suitable for the germination of upright bodies.

Claims

[Claim 1] A method for culturing appressoria of Dalasi, comprising the step of irradiating the appressoria of Dalasi with light having a wavelength range of 500 nm or more and less than 600 nm.

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