Plant cultivation method and culture bed for plant cultivation

Abstract

To provide a plant cultivation method by which plant biomass can be increased, adhesion of hyphae and spores to the plant can be prevented, and contamination of the field by the hyphae and spores can be avoided, and also to provide a culture bed for plant cultivation used around the plant in the plant cultivation method.SOLUTION: A plant cultivation method comprises: a sowing step in which seeds of a plant are sown; a growing step in which germinated seeds are cultivated to the seedlings; and a culture bed placing step in which a culture bed covered with a gas-permeable film, which allows gas to pass through, is disposed around the germinated seeds.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a plant cultivation method and a fungal bed for plant cultivation. [Background technology]

[0002] Recent climate change has had a major impact on agriculture, with abiotic stresses such as dryness and high temperatures causing growth disorders, reduced yields, and reduced quality of crops. Food production technologies that can cope with such climate change are needed.

[0003] One of the food production technologies mentioned above is the use of biostimulants (BS) to promote crop growth. One type of biostimulant is a volatile compound produced by bacteria and fungi, which is known to increase plant biomass.

[0004] On the other hand, Patent Document 1 discloses a method for controlling plant pathogenic fungi by placing mushroom mycelium, fruiting bodies, or waste mushroom beds around plants to inhibit the mycelial growth of plant pathogenic fungi, and a method for controlling plant pathogenic fungi by finely breaking up the fruiting bodies or waste mushroom beds and scattering them near plants to inhibit the mycelial growth of plant pathogenic fungi. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5561637 Summary of the Invention [Problem to be solved by the invention]

[0006] When using volatile compounds generated by the above-mentioned bacteria and fungi in plant cultivation, it is necessary to establish a mass propagation system for the bacteria or fungi, as well as to verify the effects of the bacteria or fungi used on soil, crops, and people who handle them, and the hurdle of establishing a propagation system from scratch using a new fungus is high. Furthermore, with the above-mentioned methods for controlling plant pathogens, there is a possibility that mushroom hyphae and spores will adhere to plants and that the hyphae and spores will contaminate the soil.

[0007] The present invention has been made in view of the above circumstances, and aims to provide a plant cultivation method that increases plant biomass, prevents mycelia and spores from adhering to plants, and prevents field contamination by mycelia and spores, as well as a fungal bed for plant cultivation to be used around plants in the plant cultivation method. [Means for solving the problem]

[0008] The present invention is as follows.

[0009] [1] Plant cultivation methods include: a sowing process for sowing plant seeds; A growing step of germinating the seeds and growing the germinated seeds into seedlings; and a fungal bed arranging step of arranging a fungal bed covered with a gas-permeable film around the germinated seeds.

[0010] [2] The period during which the fungal bed is placed around the germinated seeds may be at least 4 days or more.

[0011] [3] The amount of the fungal bed placed around the germinated seeds may be 15 g or more per 3 L of closed space.

[0012] [4] The fungal bed may be at least one type of fungal bed selected from the group consisting of a post-inoculation fungal bed in which mycelia are widespread, a generated fungal bed in which fruiting bodies are generated, and a waste fungal bed in which fruiting bodies have been harvested.

[0013] [5] The mushroom bed for plant cultivation is The mushroom bed and and a gas-permeable film that allows gas to pass through, The fungal bed is covered with the gas-permeable film.

[0014] [6] The fungal bed may be composed of at least one type of fungal bed selected from the group consisting of an inoculated fungal bed in which mycelia are widespread, an inoculated fungal bed in which fruiting bodies are produced, and a waste fungal bed in which fruiting bodies have been harvested. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a plant cultivation method that increases plant biomass, prevents mycelia and spores from adhering to plants, and prevents field contamination by mycelia and spores, as well as a fungal bed for plant cultivation that is used around plants in the plant cultivation method. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a schematic diagram showing the process of plant cultivation in which a fungal bed is placed around germinated seeds and the process of plant cultivation in which a fungal bed is not placed around germinated seeds. [Figure 2] FIG. 1 shows the difference in the growth promotion effect of rice seedlings using the seedbeds inoculated with two mushroom species. [Figure 3] FIG. 1 shows the difference in the growth-promoting effect on rice seedlings in each exposure plot where different amounts of fungal bed were placed. [Figure 4] This figure shows the difference in the growth promotion effect on rice seedlings in each exposure area where mushroom beds of different ages were placed using mushroom beds of Shiitake mushroom (Hokuken No. 905). [Figure 5] This figure shows the difference in the growth promotion effect on rice seedlings in each exposure area where mushroom beds of different ages were placed using mushroom beds of shiitake mushroom (Mori XR1). [Figure 6]This figure shows the difference in biomass of rice seedlings in the exposure plots where the mushroom bed was covered with high-density polyethylene film (HDPE film), the exposure plot where the mushroom bed was covered with polyvinyl chloride film (PVC film), and the exposure plot where the mushroom bed was not covered with film (OPD). [Figure 7] FIG. 1 shows the difference in whole rice biomass when rice seedlings placed in an exposed area and those placed in a non-exposed area were cultivated under an abiotic stress environment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, a plant cultivation method and a fungal bed for plant cultivation, which are modes for carrying out the present invention (hereinafter referred to as embodiments), will be described in detail. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following content. The present invention can be carried out with appropriate modifications within the scope of its gist.

[0018] [Plant cultivation method] The plant cultivation method according to the present embodiment will be described below. The plant cultivation method includes a sowing step of sowing plant seeds, a growing step of germinating the seeds and growing the germinated seeds into seedlings, and a fungal bed arrangement step of arranging a fungal bed covered with a gas-permeable film around the germinated seeds.

[0019] (Seeding process) When the conditions for germination of plant seeds are met, the seeds can be sown, for example, in the open field, in a container, in a petri dish, etc. For example, when using a petri dish, sterilized filter paper may be laid in the dish, and sterilized water may be added thereto before sowing the seeds.

[0020] (Growing process) Germinate plant seeds. The conditions for germinating plant seeds vary depending on the type of plant, so they can be set according to the type of plant. For example, grass seeds can be germinated under the following conditions. After sowing the seeds in soil, they are grown at 28°C for four days, watering as needed. During these four days, the cycle is 14 hours of daylight (14 hours of light) and 10 hours of nightlight (lights off), repeated four times. This allows the seeds to germinate.

[0021] The germinated seeds are then grown until they become seedlings. The conditions for growing them into seedlings vary depending on the type of plant, and can be set according to the type of plant. For example, grass plants can be grown under the following conditions. After the seeds germinate, they are watered appropriately and grown for 14 days. During these 14 days, the temperature is set at 27°C, 13 hours of daylight (13 hours of light), 11 hours of nighttime light (lights off), and 23°C, and this cycle is repeated 14 times. This allows the germinated seeds to grow into seedlings.

[0022] (Bacteria bed placement process) A fungal bed is placed around the germinated seeds. The fungal bed may be placed around the germinated seeds so that volatile compounds (hereinafter simply referred to as VCs or Volatile Compounds) generated from the fungal bed can reach the germinated seeds and affect their growth. The fungal bed is preferably placed, for example, within a radius of at least 3 m from the germinated seed, and more preferably within a radius of 1 m. Furthermore, as long as the fungal bed can be placed around the germinated seeds, the germinated seeds may be grown in an open space or a closed space. From the viewpoint of efficiently delivering the volatile compounds generated from the fungal bed to the germinated seeds, it is preferable to grow the germinated seeds in a closed space. Examples of open spaces include open fields and farm fields. Examples of closed spaces include vinyl greenhouses, glass greenhouses, rooms, containers, etc.

[0023] The period for which the fungal bed is placed around the germinated seeds is at least 4 days or more, more preferably 1 week or more, even more preferably 2 weeks or more, and particularly preferably 1 month or more, in order to increase the opportunity for the germinated seeds to come into contact with the volatile compounds generated from the fungal bed.

[0024] The amount of fungal bed placed around the germinating seeds is 15 g or more per 3 L of closed space, more preferably 30 g or more, in order to increase the opportunity for the germinating seeds to come into contact with the volatile compounds generated from the fungal bed.

[0025] The moisture content of the fungal bed is sufficient as long as it allows volatile compounds to be generated from the fungal bed. From the viewpoint of efficiently generating volatile compounds from the fungal bed, the moisture content of the fungal bed is 40 to 80 wt% of the total mass of the fungal bed.

[0026] The surface of the fungal bed used in the fungal bed arrangement step is covered with a gas-permeable film that allows gas to pass through, thereby preventing mushroom hyphae and spores from adhering to germinated seeds or seedlings grown from germinated seeds and preventing field contamination by hyphae and spores, while allowing only volatile compounds generated from the fungal bed to pass through.

[0027] The form of the fungal bed is not limited. Furthermore, the manner in which the fungal bed is covered with a film is not limited. For example, a fungal bed having a substantially rectangular parallelepiped or cylindrical shape may have its surface covered with a gas-permeable film, or may be stored in a sealable bag made of a gas-permeable film. Furthermore, for example, a flake-shaped or powder-shaped fungal bed may be stored in a sealable bag made of a gas-permeable film.

[0028] The gas-permeable film may be any film that allows the permeation of volatile compounds generated from the fungal bed. From the viewpoint of easy availability, examples of the gas-permeable film include high-density polyethylene film, low-density polyethylene film, polypropylene film, polylactic acid film, polybutadiene film, polyvinyl chloride, etc. Furthermore, from the viewpoint of reducing the burden on the environment, biodegradable polylactic acid film is preferred.

[0029] The thickness of the gas-permeable film is preferably 10 μm or more and 100 μm or less, more preferably 25 μm or more and 50 μm or less, from the viewpoint of improving gas permeability and facilitating handling when covering the surface of the bacterial bed with the film.

[0030] The fungal bed used in the embodiment may be any bed that emits volatile compounds useful to plants, and is preferably made from a mushroom species with an established propagation system. Examples of mushroom species that can be planted in the fungal bed include edible mushroom species such as shiitake (Lentinula edodes) and enokitake (Flammulina velutipes).

[0031] The fungal bed used in the embodiment is at least one type of fungal bed selected from the group consisting of a post-inoculation fungal bed in which mycelia are spread throughout the fungal bed, a developed fungal bed in which fruiting bodies are developed, and a waste fungal bed from which fruiting bodies have been harvested. From the viewpoint of efficiently utilizing the fungal bed from which fruiting bodies have been harvested, a waste fungal bed is preferred.

[0032] The material constituting the fungal bed used in the embodiment may be any material that allows the mycelium to spread across the bed and the fruiting bodies to be harvested, and may be, for example, a wood substrate such as sawdust, a nutrient source such as rice bran, and water.

[0033] Plants that can be cultivated by the plant cultivation method according to the present embodiment are not limited, and examples of seed plants include grasses, legumes, solanaceae, lamiaceae, Brassicaceae plants such as turnip, Japanese mustard spinach, and cabbage, Amaranthaceae plants such as spinach, and Asteraceae plants such as lettuce.

[0034] In the sowing step, a fungal bed may be placed around the sown seeds to germinate the seeds. In the growing step, a fungal bed may be placed around the seedlings even after the germinated seeds have grown into seedlings.

[0035] In addition, during the growing process, the germinated seeds may be transplanted to space them apart, so that one germinated seed is not affected by the other germinated seeds and the germinated seeds can grow without stress.

[0036] [Bed for plant cultivation] The fungal bed for plant cultivation of this embodiment is placed around the plant when the plant is cultivated. The fungal bed for plant cultivation is covered with a gas-permeable film. The shape of the fungal bed for plant cultivation is not limited. Furthermore, the manner in which the fungal bed is covered with the film is not limited. For example, a fungal bed for plant cultivation having a substantially rectangular parallelepiped or substantially cylindrical shape may have its surface covered with a gas-permeable film, or may be stored in a sealable bag made of a gas-permeable film. Furthermore, for example, a fungal bed for plant cultivation in the form of flakes or a powdered fungal bed for plant cultivation may be stored in a sealable bag made of a gas-permeable film.

[0037] The gas-permeable film may be any film that allows the permeation of volatile compounds generated from the fungal bed for plant cultivation. From the viewpoint of availability, examples of gas-permeable films include high-density polyethylene film, low-density polyethylene film, polypropylene film, polylactic acid film, polybutadiene film, and polyvinyl chloride. Furthermore, from the viewpoint of reducing the burden on the environment, biodegradable polylactic acid film is preferred.

[0038] The thickness of the gas-permeable film is preferably 6 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less, and even more preferably 10 μm or more and 25 μm or less, from the viewpoint of improving gas permeability and facilitating handling when covering the surface of the plant cultivation bed with the film.

[0039] The fungal bed for plant cultivation may be any fungal bed that emits volatile compounds useful to plants, and is preferably made from a mushroom species with an established propagation system. Examples of mushroom species that can be planted in the fungal bed include edible mushroom species such as shiitake (Lentinula edodes) and enokitake (Flammulina velutipes).

[0040] The fungal bed for plant cultivation is at least one type of fungal bed selected from the group consisting of a post-inoculation fungal bed in which mycelia are spread throughout the fungal bed, a developed fungal bed in which fruiting bodies are developed, and a waste fungal bed from which fruiting bodies have been harvested. From the viewpoint of efficiently utilizing the fungal bed from which fruiting bodies have been harvested, a waste fungal bed is preferred.

[0041] The materials constituting the fungal bed for plant cultivation need only be materials that allow mycelia to spread over the bed and fruiting bodies to be harvested, and may include, for example, a wood substrate such as sawdust, a nutrient source such as rice bran, and water. The moisture content of the fungal bed for plant cultivation is 40 to 80 wt% of the total mass of the fungal bed from the viewpoint of efficiently generating volatile compounds from the fungal bed.

[0042] As described above, the biomass of plants cultivated by the plant cultivation method of this embodiment and plants cultivated around a fungal bed for plant cultivation increases. Furthermore, the plant cultivation method and fungal bed for plant cultivation of this embodiment can prevent mushroom mycelia and spores from adhering to plants. Furthermore, field contamination by mycelia and spores can be prevented. [Example]

[0043] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples in any way.

[0044] (Example) As shown in Figure 1, a petri dish 1 was prepared by placing sterilized filter paper on the surface and adding sterilized water to the petri dish 1, and sterilized grass seeds 2 were sown in the petri dish 1. After sowing the seeds 2, they were grown at 28°C for four days, watered appropriately. During these four days, the cycle was changed to 14 hours of daylight (14 hours of light exposure) and 10 hours of nightlight (lights off), and this cycle was repeated four times to germinate the seeds 2, yielding germinated seeds 21.

[0045] Next, germinated seeds 21 with approximately the same growth rate were selected and transplanted into plant boxes 31 and 32 containing water-soaked, sterilized soil. The same number of germinated seeds 21 were transplanted into plant boxes 31 and 32. Next, two 3 L containers 41 and 42 were prepared. The plant box 31 into which the germinated seeds 21 had been transplanted was placed in container 41. The plant box 32 into which the germinated seeds 21 had been transplanted and a fungal bed 43 were placed in container 42. The moisture content of the fungal bed was 40 to 80 wt% of the total mass of the fungal bed. The space in container 42 in which the fungal bed 43 was placed is also referred to as the exposed area. The space in container 41 in which the fungal bed 43 was not placed is also referred to as the non-exposed area.

[0046] Germinated seeds 21 were placed in exposed and non-exposed areas for a certain period of time, and the biomass of seedlings grown from the germinated seeds 21 was measured when (1) mushroom species, (2) mushroom bed volume, (3) mushroom species strain and mushroom bed age, and (4) film covering the mushroom bed were changed. Specifically, for each of (1) to (4), the germinated seeds 21 were transplanted into plant boxes 31 and 32 and grown with watering as needed for 14 days. During these 14 days, the temperature was set at 27°C for 13 hours of daylight (14 hours of light) and 23°C for 11 hours of nightlight (lights off), and this cycle was repeated 14 times. The biomass of seedlings grown from germinated seeds 21 in the exposed area and the biomass of seedlings grown from germinated seeds 21 in the non-exposed area were then measured.

[0047] Biomass was measured using the following procedure. First, seedlings grown in the exposed and unexposed areas were placed in separate glass bottles and freeze-dried under vacuum at -48°C for at least 16 hours. Next, the weight of each individual seedling after freeze-drying was measured using a direct-reading balance. The weight obtained for each individual seedling was used as the biomass for that individual seedling.

[0048] The obtained biomass data was also verified as follows. First, the mean and standard deviation were calculated from the obtained data. Next, an F-test was used to confirm whether the variance of the data in the exposed and unexposed areas was equal, and then a Tukey test was performed to verify significant differences.

[0049] (1) Mushroom species Germinated seeds were placed in exposure plots containing different mushroom saplings for a set period of time, and the effects of volatile compounds (hereafter referred to as VCs or Volatile Compounds) on the growth of rice seedlings were examined. As shown in Figure 2, the biomass of seedlings grown in the exposure plot containing Enokitake mushroom saplings increased by approximately 120–160% compared to seedlings grown in the non-exposed plot. Furthermore, the biomass of seedlings grown in the exposure plot containing Shiitake mushroom saplings increased by approximately 150–170% compared to seedlings grown in the non-exposed plot. These results demonstrate that the volatile compounds (VCs) derived from Enokitake mushroom saplings and Shiitake mushroom saplings promote plant growth and increase biomass.

[0050] The materials used in the above study were as follows: Mushroom species used: Enokitake Mori No. 75, Shiitake Mori XR-1. Used mushroom beds: Incubation bed for growing Enoki mushrooms (Enoki mushroom bed), incubation bed for growing Shiitake mushrooms (Shiitake bed).

[0051] The number of rice seedlings was set to 5, and the average biomass obtained is shown in the bar graph in Figure 2. The error bars in Figure 2 indicate standard deviation. Bars marked with * or *** in Figure 2 were obtained by performing an F-test to check whether the data variances were equal, followed by a Tukey test. In Figure 2, * indicates p<0.05, and *** indicates p<0.001. For example, "p<0.05" indicates a p-value of less than 0.05, indicating a confidence level of 95%. Specifically, if 100 experiments were performed, data could be extracted within a range that included the population average value 95 times. The same applies below.

[0052] Table 1 shows biomass data for the unexposed area where no mushroom bed was placed, and the exposed areas where mushroom beds using different mushroom species were placed. Figure 2 is a graph created based on the data in Table 1.

[0053] [Table 1]

[0054] (2) Amount of mushroom bed Germinated seeds were placed in each exposure area with different amounts of mushroom substrate for a set period of time, and the effect of volatile compounds (VCs) on the growth of rice seedlings was examined during this time. As shown in Figure 3, seedling biomass increased with increasing mushroom substrate volume. In particular, biomass increased significantly when the mushroom substrate volume exceeded 15 g per 3 L of volume. For example, the biomass of seedlings grown in the exposure area with a 15 g mushroom substrate volume was found to be approximately 150% higher than that of seedlings grown in the non-exposed area. It was found that increasing the mushroom substrate volume also increased the amount of mushroom substrate-derived volatile compounds (VCs), which promoted plant growth and increased biomass.

[0055] The materials used in the above study were as follows: (i) Mushroom species used: Shiitake Mori XR-1. (ii) Used mushroom bed: mushroom bed from which shiitake mushrooms grow (shiitake mushroom bed).

[0056] The number of rice seedlings was set to 5, and the average biomass values ​​obtained are shown in the bar graph in Figure 3. The error bars in Figure 3 indicate standard deviation. In the bar graph in Figure 3, bars marked with ** or *** were obtained by using an F-test to check whether the data variances were equal, followed by a Tukey test. In Figure 3, ** indicates p<0.01, and *** indicates p<0.001. Table 2 shows biomass data for the non-exposed area where no mushroom bed was placed, and the exposed areas where mushroom beds with different amounts of mushroom bed were placed. Figure 3 is a graph created based on the data in Table 2.

[0057] [Table 2]

[0058] (3) Mushroom species and age of the mushroom bed Germinated seeds were placed in exposure plots containing different strains of mushrooms and different ages of mushroom substrates for a set period of time, and the effects of volatile compounds (VCs) on the growth of rice seedlings were examined during this period. Specifically, we used Shiitake mushroom (Hokuken No. 905) mushroom substrates and examined the differences in rice seedling biomass in each exposure plot containing different ages of mushroom substrates: inoculated mushroom substrates, emerged mushroom substrates, and waste mushroom substrates. As shown in Figure 4, we found that rice seedling biomass increased in all exposure plots, including inoculated mushroom substrates, emerged mushroom substrates, and waste mushroom substrates. In particular, we found that the biomass of rice seedlings grown in the exposure plots containing younger mushroom substrates, i.e., inoculated mushroom substrates, increased by approximately 150–200% compared to the biomass of seedlings grown in the non-exposed plots. Furthermore, although the effect was less than that of the inoculated mushroom bed, the biomass of rice seedlings grown in the exposed area with the inoculated mushroom bed and the exposed area with the waste mushroom bed also increased by approximately 120-170% compared to the biomass of rice seedlings grown in the non-exposed area. These results show that the younger the mushroom bed, the greater the effect of increasing the biomass of rice seedlings.

[0059] Next, we used a mushroom bed of Lentinus edodes (Mori XR-1) as a different strain of mushroom to examine the differences in rice seedling biomass in different exposure areas using different ages of mushroom beds: inoculated mushroom beds, emerged mushroom beds, and waste mushroom beds. As shown in Figure 5, we found that rice seedling biomass increased in all exposure areas using inoculated mushroom beds, emerged mushroom beds, and waste mushroom beds. In particular, we found that the biomass of rice seedlings grown in the exposed area using inoculated mushroom beds increased by approximately 160–230% compared to the biomass of rice seedlings grown in the unexposed area. Furthermore, although less effective than the inoculated mushroom beds, we also found that the biomass of rice seedlings grown in the exposed area using emerged mushroom beds and the exposed area using waste mushroom beds increased by approximately 120–230% compared to the biomass of rice seedlings grown in the unexposed area. These results indicate that the biomass of rice seedlings increases when germinated seeds are placed in an exposure plot containing a fungal substrate made from different strains of mushroom for a certain period of time. Furthermore, the biomass of rice seedlings grown from young fungal substrates, i.e., germinated seeds placed in an exposure plot containing a fungal substrate after inoculation for a certain period of time, shows a higher rate of increase than the biomass of rice seedlings grown in an exposure plot containing a fungal substrate or a waste fungal substrate.

[0060] The error bars in Figures 4 and 5 indicate standard deviations. Bar graphs in Figures 4 and 5 marked with *, **, or *** were obtained by performing an F-test to check whether the data variances were equal, followed by a Tukey's test. In Figures 4 and 5, * indicates p<0.05, ** indicates p<0.01, and *** indicates p<0.001.

[0061] Table 3 shows the biomass data for rice seedlings grown in a non-exposed area where no mushroom bed was placed, and in an exposed area where a mushroom bed of Shiitake mushroom (Hokuken No. 905) was placed. The biomass data is the average biomass data obtained when the number of rice seedlings was set to 5. Figure 4 is a graph created based on the data in Table 3.

[0062] [Table 3]

[0063] Table 4 shows the biomass data for rice seedlings grown in a non-exposed area where no mushroom bed was placed, and in an exposed area where a mushroom bed of Shiitake mushroom (Mori XR-1) was placed. The biomass data is the average biomass data obtained when the number of rice seedlings was set to 5. In Table 4, Mori XR-1 is referred to as Mori XR1. Figure 5 is a graph created based on the data in Table 4.

[0064] [Table 4]

[0065] (4) Film covering the mushroom bed Germinated seeds were placed on a gas-permeable film-covered mushroom bed for a set period of time, and the effects of volatile compounds (VCs) on the growth of rice seedlings were examined during this period. Specifically, differences in the biomass of rice seedlings were examined in the following exposure plots: a mushroom bed covered with a 10 μm-thick high-density polyethylene film (HDPE film), a mushroom bed covered with an 11 μm-thick polyvinyl chloride film (PVC film), and a mushroom bed without a film (OPD). As shown in Figure 6, although the increase in biomass was not as high as that of rice seedlings grown on an OPD exposure plot, the biomass of rice seedlings grown on a gas-permeable film-covered mushroom bed increased by approximately 130–160%. This experiment demonstrated that volatile compounds diffuse from the mushroom bed through the gas-permeable film and affect seedling growth. Furthermore, since the fungal bed covered with such a film is placed around the germinated seeds with the film in between, contamination of the installation environment with spores and mycelium can be prevented.

[0066] The materials used in the above study were as follows: (i) Mushroom species used: Shiitake mushroom Mori XR-1 (referred to as Mori XR1 in Table 5). (ii) Bacterial bed used: generated bacterial bed. (iii) Amount of mushroom substrate used: 15 g for a volume of 3 L. (iv) High-density polyethylene film: Fukusuke Kogyo Co., Ltd., food sheet, thickness 10 μm; polyvinyl chloride film: Backstyle Co., Ltd., food packaging wrap film, thickness 7.6 μm. (v) Bacterial bed covered with gas-permeable film: The entire 15 g of bacterial bed was covered with gas-permeable film so that it was covered with one layer of gas-permeable film. (vi) Open petri dish (OPD): 15 g of the fungal substrate was placed on a petri dish.

[0067] The number of rice seedlings was five, and the average biomass obtained is shown in the bar graph in Figure 6. The error bars in Figure 6 indicate standard deviation. In the bar graph in Figure 6, bars marked with *, **, or *** were tested by F-test to determine whether the data variances were equal, followed by a Tukey's test. In Figure 6, * indicates p<0.05, ** indicates p<0.01, and *** indicates p<0.001. Table 5 shows the biomass data for rice seedlings grown in the non-exposed area without a fungal substrate, the exposed areas with different types of fungal substrates covered with film, and the exposed area with a fungal substrate not covered with film. Note that Figure 6 was created based on the data in Table 5.

[0068] [Table 5]

[0069] As described above, it was confirmed that placing germinated seeds in an exposure plot with a fungal bed for a certain period of time increased the biomass of rice seedlings grown from the germinated seeds. It was also confirmed that placing germinated seeds in an exposure plot with a fungal bed covered with a gas-permeable film for a certain period of time increased the biomass of rice seedlings grown from the germinated seeds. Furthermore, because the fungal bed covered with a gas-permeable film is placed around the germinated seeds via the film, contamination of the installation environment with spores and mycelium can be prevented.

[0070] In addition to the above studies, rice seedlings grown from germinated seeds placed in an exposure plot containing a fungal bed for a certain period of time (two weeks in this example) were grown in the open field under abiotic stress conditions such as dryness and high temperature, and it was found that the total rice biomass increased. As shown in Figure 7, when rice seedlings grown from germinated seeds placed in an exposure plot were grown under an abiotic stress environment, the total rice biomass increased by approximately 105 to 160% compared to the total rice biomass when rice seedlings grown from germinated seeds placed in a non-exposure plot were grown under an abiotic stress environment. This demonstrates that rice grown by the plant cultivation method of this embodiment is tolerant to abiotic stress environments.

[0071] The materials used in the above study were as follows: (i) Mushroom species used: Shiitake mushroom Mori XR-1 (referred to as Mori XR1 in Table 6), Shiitake mushroom Kitaken 905. (ii) Used mushroom bed: mushroom bed from which shiitake mushrooms grow (shiitake mushroom bed). (iii) The moisture content of the fungal bed was 50 to 70 wt % of the total mass of the fungal bed.

[0072] The seedlings that were germinated in the exposed area and grown for two weeks in the non-exposed area were cultivated under the abiotic stress environment under the following conditions. (i) Cultivation conditions: In a 24-hour cycle, light was irradiated for 14.5 hours, humidity was 40% or less, and the temperature was 31°C, and for the remaining 9.5 hours, the light was turned off, humidity was 40% or less, and the temperature was 27°C. Photoperiod was adjusted using natural and artificial light. (ii) Cultivation period: Approximately 4 months. During this period, water was provided as needed and the seeds were cultivated until ripened. (iii) Drying period: After cultivation, watering was withheld and the rice was allowed to dry for at least two weeks. After that, the rice was dug up from the soil, the soil was washed off from the roots, and the rice was allowed to dry at room temperature for one month.

[0073] The number of rice plants was 5, and the average biomass values ​​obtained are shown in the bar graph in Figure 7. The error bars in Figure 7 indicate standard deviation. In the bar graph in Figure 7, bars marked with * or ** were obtained by using an F-test to check whether the data variances were equal, followed by a Tukey's test. In Figure 7, * indicates p<0.05, and ** indicates p<0.01. Table 6 shows the data for the biomass of rice plants grown from seedlings grown from germinated seeds in the non-exposed area without a fungal bed, and the biomass of rice plants grown from seedlings grown from germinated seeds in the exposed area with a fungal bed. Figure 7 is a graph created based on the data in Table 6.

[0074] [Table 6]

[0075] In addition, rice seedlings grown from germinated seeds left in the non-exposed area for 2 weeks and those grown from germinated seeds left in the exposed area for 2 weeks were transplanted into pots and grown under abiotic stress and non-exposed conditions, and the quality of the brown rice harvested from each plant was examined. The brown rice harvested from the exposed rice plants had a whole grain rate of approximately 95% or more. In contrast, the whole grain rate of the brown rice harvested from the non-exposed rice plants was approximately 78%. These results suggest that the quality of the brown rice harvested from rice seedlings grown from germinated seeds left in the exposed area for 2 weeks grown under abiotic stress and non-exposed conditions is superior to that of rice seedlings grown from germinated seeds left in the non-exposed area for 2 weeks grown under abiotic stress and non-exposed conditions. That is, it was found that the plant cultivation method of this embodiment can improve the quality of harvested brown rice even when rice is placed under an abiotic stress environment. Here, the whole grain rate refers to the proportion of whole grains to the total amount of harvested brown rice. Whole grains refer to seeds (brown rice) that are highly transparent and free of cloudy areas.

[0076] As described above, the biomass of plants cultivated by the plant cultivation method of this embodiment and plants cultivated using a fungal bed for plant cultivation increases. Furthermore, because the fungal bed is covered with a gas-permeable film, it is possible to prevent mycelia and spores from adhering to the plants. Furthermore, because the fungal bed is placed around the germinated seeds via the gas-permeable film, it is possible to prevent field contamination by mycelia and spores.

[0077] Furthermore, even when seedlings grown from germinated seeds placed in an exposed area with a fungal bed for a certain period of time are cultivated under abiotic stress environments such as dryness and high temperatures, the biomass of the entire plant increases. Furthermore, the quality of the seeds harvested from the plants is improved. Therefore, rice cultivated by the plant cultivation method of this embodiment has tolerance to abiotic stress environments.

[0078] Although the present invention has been described above using embodiments, various embodiments and modifications of the present invention are possible without departing from the broad spirit and scope of the present invention. Furthermore, the above-described embodiments are intended to explain the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the scope of the meaning of the invention equivalent thereto are considered to be within the scope of the present invention. [Explanation of symbols]

[0079] 1 Petri dish, 2 seeds, 21 germinated seeds, 31, 32 plant boxes, 41, 42 containers, 43 mushroom beds.

Claims

1. a sowing process for sowing plant seeds; A growing step of germinating the seeds and growing the germinated seeds into seedlings; A fungal bed arrangement step of arranging a fungal bed covered with a gas-permeable film around the germinated seeds.

2. 2. The plant cultivation method according to claim 1, wherein the fungal bed is placed around the germinated seeds for at least four days.

3. 3. The plant cultivation method according to claim 1, wherein the amount of the fungal bed placed around the germinated seeds is 15 g or more per 3 L of closed space.

4. 3. The plant cultivation method according to claim 1 or 2, wherein the fungal bed is at least one type of fungal bed selected from the group consisting of a post-inoculation fungal bed in which mycelia are spread throughout the fungal bed, a developed fungal bed in which fruiting bodies are developed, and a waste fungal bed from which fruiting bodies have been harvested.

5. The mushroom bed and and a gas-permeable film that allows gas to pass through, The fungal bed for plant cultivation is covered with the gas-permeable film.

6. The fungal bed for plant cultivation according to claim 5, wherein the fungal bed is composed of at least one type of fungal bed selected from the group consisting of a post-inoculation fungal bed in which mycelia are spread throughout the fungal bed, a development fungal bed in which fruiting bodies are developed, and a waste fungal bed in which fruiting bodies have been harvested.

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