Plant composition, fungicide, and method for growing plants

Abstract

This provides novel technologies for the effective utilization of plant biomass. [Solution] The plant composition contains plasma-treated biomass obtained by irradiating plant biomass with plasma.

Description

Technical Field

[0001] The present disclosure relates to a composition for plants, a bactericide, and a method for growing plants.

Background Art

[0002] Patent Document 1 discloses a composition for plants containing a yeast cell wall degradation product and histidine. This composition for plants is described as being usable as a biostimulant.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors of the present application have long been conducting research using plasma. As part of the research, they are examining techniques for effectively utilizing plant biomass by subjecting it to plasma treatment. [[ID=�6]]

[0005] The present disclosure has been made in view of the above circumstances, and an object thereof is to provide a novel technique related to the effective utilization of plant biomass.

Means for Solving the Problems

[0006] The composition for plants according to the first aspect of the present disclosure contains plasma-treated biomass obtained by irradiating plant biomass with plasma.

[0007] The bactericide according to the second aspect of the present disclosure contains plasma-treated biomass obtained by irradiating plant biomass with plasma.

[0008] A third aspect of this disclosure, a method for cultivating plants, involves cultivating plants in a nutrient solution or soil containing plasma-treated biomass obtained by irradiating plant biomass with plasma.

[0009] This disclosure provides novel technologies for the effective utilization of plant biomass. [Brief explanation of the drawing]

[0010] [Figure 1] This is a photograph showing the results of a growth experiment of Arabidopsis thaliana (day 21). [Figure 2] This graph shows the measurement results of the above-ground weight during a growth experiment of Arabidopsis thaliana (day 21). [Figure 3] These are photographs showing the condition of the roots and the development of chlorosis in Arabidopsis thaliana during a growth experiment (days 7 and 14). [Figure 4] This is a magnified photograph showing the roots of Arabidopsis thaliana during a growth experiment (day 14). [Figure 5] This graph shows the results of gene expression analysis of Arabidopsis thaliana using quantitative PCR. [Figure 6] This graph shows the results of an E. coli growth experiment. [Modes for carrying out the invention]

[0011] First, embodiments of this disclosure will be listed and described. [1] A plant composition containing plasma-treated biomass obtained by irradiating plant biomass with plasma. [2] The plant composition described in [1] for use in biostimulant materials. [3] The plant biomass is the non-edible part of the plant, as described in [1] or [2]. [4] A fungicide containing plasma-treated biomass obtained by irradiating plant biomass with plasma. [5] The fungicide described in [4] for use in plant cultivation. [6]A method for growing plants, which comprises cultivating plants in a nutrient solution or soil containing plasma-treated biomass obtained by irradiating plant biomass with plasma.

[0012] The present disclosure will be described with reference to the drawings. In this specification, in the description of a numerical range using "or more" and "or less", unless otherwise specified, it is assumed to include the lower limit value and the upper limit value. For example, in the description of "10 or more and 20 or less", it is assumed to include both the lower limit value of "10" and the upper limit value of "20". Also, in this specification, the upper limit value and the lower limit value of each numerical range can be arbitrarily combined.

[0013] 1. Composition for plants The composition for plants of this embodiment contains plasma-treated biomass obtained by irradiating plant biomass with plasma.

[0014] (1) Plant biomass The plant biomass is not particularly limited, and various plant biomasses can be used. From the viewpoint of avoiding competition with food production, it is preferably a non-edible part of the plant. From the viewpoint of material recycling, it is also preferably waste material or unused material. Unused materials are, for example, unused thinned wood and main felling residues left in forest land without being used.

[0015] Specific examples of plant biomass are Rice straw, wheat straw, corn stover (corn stalk and leaf part), buckwheat stalk and leaf part, vegetable stalk and leaf part, etc., which are agricultural wastes; Sugarcane bagasse, sorghum bagasse, sugar beet pulp, orange pulp, rice husk, bran, etc., which are primary processing residues of foods, etc.; Tea leaves, coffee grounds, okara, shochu residues, etc., which are manufacturing residues of foods, etc.; Erianthus, miscanthus, giant miscanthus (ogisusuki), switchgrass, napier grass, etc., which are energy crops; Weeds, turfgrass, pampas grass, reed, bamboo, etc. planted in riverbanks, roadsides, wastelands, etc., as other herbaceous residues; Materials, bark, branches and leaves derived from broad-leaved trees such as beech, oak, chestnut, horse chestnut, zelkova, willow, poplar, etc.; Materials, bark, stems and leaves derived from coniferous trees such as cedar, cypress, pine, etc.; Algae such as hondawara, kombu, wakame, tengusa, aosa, kasanori, etc.; Furthermore, aquatic plants and microalgae; and the like. The plant biomass may be only one kind or two or more kinds.

[0016] The components contained in the plant biomass are not particularly limited. The plant biomass usually contains lignocellulose. Lignocellulose is the main component of the plant cell wall and is composed of cellulose, hemicellulose, and lignin. Cellulose is a polysaccharide in which glucose is β-1,4 glycosidically bonded. Hemicellulose is a polysaccharide composed of various sugars. Lignin is a polymer of aromatic compounds.

[0017] The size and shape of the plant biomass are not particularly limited. From the viewpoint of increasing the surface area and improving the efficiency of plasma treatment, the plant biomass is preferably a pulverized or cut product. The shape of the plant biomass is not particularly limited and may be, for example, rod-shaped, fibrous, granular, chip-shaped, flaky, paste-shaped, etc. From the viewpoints of the efficiency of plasma treatment and handling properties, etc., the maximum length is preferably 10 cm or less, and may be 5 cm or less, 3 cm or less, 1 cm or less. The lower limit value of the above maximum length is not particularly limited and is, for example, 0.1 μm or more.

[0018] (2) Plasma-treated biomass Plasma-treated biomass is obtained by irradiating plant biomass with plasma. To date, the inventors of this invention have shown that direct treatment with atmospheric pressure plasma has a bactericidal effect on various microorganisms such as E. coli and yeast. Furthermore, the inventors have also shown that the bactericidal effect is enhanced in tryptophan solutions treated with atmospheric pressure plasma. However, since the bactericidal effect of direct treatment with atmospheric pressure plasma or tryptophan solutions treated with atmospheric pressure plasma is exerted by radical intermediates produced by the plasma treatment, improvements were desired in the following respects. Specifically, the radical intermediates produced by the plasma treatment have a short bactericidal effect and are unsuitable for storage, posing a problem in that they must be used immediately after plasma treatment. The inventors of this invention have conducted extensive research and have newly discovered that plasma-treated biomass can exhibit the desired effect even several weeks after plasma treatment, leading to the development of the technology disclosed hereto.

[0019] The conditions for plasma treatment are not particularly limited as long as they achieve the effects of the present invention. Atmospheric pressure plasma treatment is preferred. Here, atmospheric pressure plasma refers to plasma with a pressure in the range of 0.1 atmospheres to 2.0 atmospheres.

[0020] The method for generating plasma is not particularly limited. Examples of plasma generation methods include glow discharge, hollow cathode discharge, dielectric barrier discharge, inductively coupled plasma discharge (ICP), capacitively coupled plasma discharge (CCP), corona discharge, streamer discharge, and arc discharge. Among these, glow discharge is preferred because it can obtain relatively high plasma, electron, and radical densities and makes it easy to maintain a low plasma gas temperature. The type of gas to which voltage is applied to generate plasma is not particularly limited. The type of gas is preferably one or more gases selected from the group consisting of oxygen, argon, nitrogen, carbon dioxide, and hydrogen, and air is more preferred from a cost standpoint.

[0021] The plasma density is, for example, 1 × 10⁻⁶ 13 cm -3 The above 1 x 1016 cm -3 The following ranges are preferable. The plasma temperature at the location of the irradiated object can be adjusted according to the distance from the needle electrode of the radical generator to the irradiated object, the power, and the irradiated object processing flow rate. For example, by setting the distance from the needle electrode to the irradiated object to 3 mm or more and 30 mm or less, the power to 10 W to 50 W, and the irradiated object flow rate to 0 L / min to 1 L / min, the plasma temperature irradiated onto the plant biomass can be optimized. The plasma irradiation time is, for example, 0.1 seconds or more. The upper limit of the plasma irradiation time is not particularly limited and may be, for example, 8 hours or less, 2 hours or less, or 30 minutes or less. In the technology disclosed herein, the object to which the plasma is irradiated is plant biomass, not the plants themselves that are to be grown or the bacteria that are to be killed. Therefore, the technology disclosed herein has fewer constraints on plasma processing conditions and is a highly practical technology.

[0022] Plasma irradiation is preferably performed on plant biomass immersed in an immersion solution. The immersion solution is preferably an aqueous sodium hydroxide solution or water. The concentration of the aqueous sodium hydroxide solution is preferably, for example, 10 mM to 0.5 M. The amount of plant biomass relative to the immersion solution is preferably 0.01% (w / v) to 50% (w / v), more preferably 0.05% (w / v) to 25% (w / v), and even more preferably 0.1% (w / v) to 10% (w / v). In this specification, an amount of plant biomass of 1% (w / v) means that 1 g of plant biomass is contained in 100 mL of solution. Plasma irradiation is useful because it can simultaneously supply nitric acid from the atmosphere (air) and neutralize the liquid, but it is also possible to create a solution without nitric acid by filling the chamber covering the space between the needle electrode and the sample with Ar (argon) gas so that the liquid sample does not come into contact with the outside air.

[0023] Currently, the active ingredients in plasma-treated biomass for use in plant compositions and / or fungicides have not yet been identified. The inventors of this application have confirmed that plasma treatment of lignocellulose generates organic carboxylic acids, monomers or oligomers derived from cellulose, monomers or oligomers derived from hemicellulose, and monomers or oligomers derived from lignin, etc. Examples of organic carboxylic acids include oxalic acid and succinic acid. One or more of these compounds contained in plasma-treated biomass may contribute to the effectiveness of the plant composition and / or fungicide. Since these compounds contained in plasma-treated biomass exist more stably than radical intermediates, etc., it is presumed that plasma-treated biomass can maintain its effectiveness as a plant composition and / or fungicide over a long period of time. This disclosure shall not be limited by this presumption.

[0024] The form of the plant composition (plasma-treated biomass) is not particularly limited. The plasma-treated biomass may be solid material of plant biomass irradiated with plasma, or a solution containing plant biomass irradiated with plasma (hereinafter also referred to as plasma-treated biomass solution). The plasma-treated biomass solution may be, for example, a mixture of the above-mentioned immersion solution and plasma-treated biomass. If an alkaline solution is used as the immersion solution, it is preferable to adjust the pH (25°C) of the plasma-treated biomass solution to 5.0 or higher and 7.0 or lower using an acidic solution before applying it to plants.

[0025] (3) Target plants The target plants to which the plant composition (plasma-treated biomass) can be applied are not particularly limited. The plant composition can be applied as a biostimulant material to various plants, including angiosperms and gymnosperms. Plasma-treated biomass may affect auxin response and iron response, and is considered a highly versatile technology with little plant species specificity.

[0026] Examples of plants to which the present invention can be applied include Brassicaceae plants such as Arabidopsis thaliana and Brassica napus, Fabaceae plants such as soybeans, Poaceae plants such as rice, corn, wheat and barley, Euphorbiaceae plants such as castor bean, cassava and jatropha, Asteraceae plants such as lettuce, Solanaceae plants such as tomatoes, Rosaceae plants such as strawberries, and Salicaceae plants such as poplars.

[0027] (4) Uses of plant-based compositions The applications of the plant composition are not particularly limited. The plant composition is suitable as a biostimulant material. Biostimulants are attracting attention as a new technology that reduces plant damage caused by climate and soil conditions by controlling abiotic stress on plants, thereby providing healthy plants.

[0028] Biostimulant materials are useful as plant growth promoters. The plant growth promoters of this disclosure may exert one or more effects selected from the group consisting of, for example, increasing the weight of above-ground parts, promoting root hair growth, promoting mineral absorption, suppressing chlorosis, and conferring pathogen resistance. In this disclosure, biostimulant materials may also be used as priming agents. Priming agents are agents that activate the plant's inherent stress tolerance mechanisms by treating the plant with a compound before environmental stress occurs, enabling the plant to exhibit resistance quickly and strongly when actually subjected to stress. An example of environmental stress is iron deficiency stress. Iron is an essential element for plants, and it is known that a deficiency prevents chlorophyll synthesis, causing leaves to yellow (chlorosis).

[0029] The plant-based compositions are also useful as fungicides for plant cultivation. The explanation for fungicides used in plant cultivation is the same as described in "2. Fungicides" below.

[0030] The method for growing plants using plant-derived compositions (plasma-treated biomass) will be explained later in "3. Method for Growing Plants".

[0031] 2. Disinfectant The fungicide of this embodiment contains plasma-treated biomass obtained by irradiating plant biomass with plasma. In this embodiment, the descriptions of plant biomass and plasma-treated biomass in the fungicide are the same as those given in "(1) Plant Biomass" and "(2) Plasma-treated Biomass" in "1. Compositions for Plants".

[0032] The uses of fungicides are not particularly limited. Preferably, the fungicide is one that kills one or more types of fungi, bacteria, and viruses. Fungi, bacteria, and viruses may include pathogens that cause plant diseases as well as pathogens that are harmful to humans.

[0033] The fungicide may be a fungicide for use in plant cultivation (hereinafter also referred to as a fungicide for plant cultivation), or it may be a fungicide for use other than plant cultivation. Examples of uses other than plant cultivation include sterilization of tools or agricultural machinery, sterilization of plant cultivation facilities, sterilization of animal breeding facilities, sterilization of the inside or outside of houses, and sterilization of fish and shellfish.

[0034] Plant cultivation fungicides are a highly versatile technology with few restrictions on the target plants, due to their nature of killing microorganisms (bacteria, etc.) and contributing to plant cultivation. Plant cultivation fungicides may be used by mixing them with the nutrient solution or soil used for plant cultivation, or by applying them directly to the plants. The case of mixing them with the nutrient solution or soil will be explained later in "3. Plant Cultivation Methods". When applying them directly to plants, for example, a plasma-treated biomass solution can be sprayed directly onto the plants. Furthermore, if the plasma-treated biomass solution sprayed on the plants falls onto the nutrient solution or soil, it can also be used to disinfect the nutrient solution or soil.

[0035] Plant cultivation fungicides are also useful as biostimulant materials as described above. For biostimulant materials, the explanations in "(3) Target Plants" and "(4) Uses of Plant Compositions" in "1. Plant Compositions" above apply directly. The method of growing plants using a fungicide (plasma-treated biomass) will be explained later in "3. Plant Cultivation Method".

[0036] 3. Plant cultivation methods The plant cultivation method of this embodiment involves cultivating plants in a nutrient solution or soil containing plasma-treated biomass obtained by irradiating plant biomass with plasma. In the plant cultivation method, the descriptions of plant biomass and plasma-treated biomass are the same as those in "1. Compositions for Plants" under "(1) Plant Biomass" and "(2) Plasma-treated Biomass". The description of the plants to be cultivated is the same as that in "1. Compositions for Plants" under "(3) Target Plants".

[0037] Nutrient solution is a liquid containing nutrients necessary for plant growth. Hydroponics is a cultivation method that uses nutrient solution to grow plants, and includes hydroponics without a growing medium, spray cultivation, and solid-culture cultivation using a growing medium. Conventionally, it has been difficult to add organic matter to nutrient solution because directly adding organic matter generates harmful intermediate decomposition products, which can damage plant roots and make them more susceptible to disease. The technology disclosed in this disclosure is groundbreaking in that it enables the healthy cultivation of plants using a nutrient solution containing plasma-treated biomass that contains organic matter.

[0038] The amount of plasma-treated biomass to be added to the nutrient solution can be appropriately set within the range that produces the desired effect. From the viewpoint of effectiveness as a biostimulant material and / or bactericidal effect, the amount of plasma-treated biomass relative to the nutrient solution is preferably 0.001% (w / v) or more, more preferably 0.01% (w / v) or more, even more preferably 0.015% (w / v) or more, and particularly preferably 0.02% (w / v) or more. Considering the effect on the components of the nutrient solution, the amount of plasma-treated biomass relative to the nutrient solution is preferably 5% (w / v) or less, more preferably 1% (w / v) or less, even more preferably 0.8% (w / v) or less, and particularly preferably 0.3% (w / v) or less. From these perspectives, the amount of plasma-treated biomass relative to the nutrient solution is preferably 0.001% (w / v) to 5% (w / v), more preferably 0.01% (w / v) to 1% (w / v), even more preferably 0.015% (w / v) to 0.8% (w / v), and particularly preferably 0.02% (w / v) to 0.3% (w / v). In this embodiment, since the weight of plant biomass does not change before and after plasma treatment, the weight of plasma-treated biomass is specified as the amount of plant biomass used as raw material.

[0039] Application to the soil can be done by spraying, drenching, mixing, or laying. When applying to the soil, it is best to ensure that the active ingredients reach the plant's rhizosphere. The amount of plasma-treated biomass mixed into the soil can be appropriately set within the range that produces the desired effect, for example, it can be between 0.001 parts by weight and 5 parts by weight per 100 parts by weight of soil.

[0040] In plant cultivation methods, plasma-treated biomass can be applied to plants or parts thereof (e.g., seeds, seedlings, or mature plants) at any growth stage, including before or after germination. The plasma-treated biomass may be applied to plants once or multiple times.

[0041] The method for cultivating plants is simply to grow them using conventional methods, other than cultivating them in a nutrient solution or soil containing plasma-treated biomass. In other words, this plant cultivation method is easy to implement because it can be carried out without introducing any special operations or equipment other than cultivating plants in a nutrient solution or soil containing plasma-treated biomass.

[0042] 4. Effects of this embodiment This embodiment utilizes plasma-treated plant biomass to create a new concept of plant-derived composition and / or fungicide that differs from conventional chemical fertilizers and pesticides. Because plasma-treated biomass is derived from plant biomass, its use does not increase net CO2 emissions, while simultaneously contributing to increased CO2 absorption through increased production of agricultural plants, thus contributing to the construction of a comprehensive carbon recycling society. Furthermore, because the plant composition and / or fungicide of this embodiment uses plasma-treated biomass as an active ingredient, it has a longer lifespan and superior storage properties compared to radical intermediates produced by plasma treatment. By cultivating plants using such materials, a positive effect can be achieved on the plants.

[0043] Furthermore, when the plant composition is used as a biostimulant, it can have a positive effect on plants in terms of yield, plant health, and stress tolerance. Currently, increasing the production of food plants and securing green spaces are global challenges, and the use of this plant composition is expected to be beneficial. Furthermore, when the plant composition is made from the non-edible parts of a plant, it can effectively contribute to the realization of sustainable food production.

[0044] Furthermore, when fungicides are used in plant cultivation, they can suppress plant diseases. Currently, increasing the production of food plants and securing green spaces are global challenges, and the use of this fungicide is expected. In addition, when fungicides are used in plant cultivation, they can reduce harmful bacteria attached to plants, contributing to the improvement of the quality of agricultural and horticultural crops. [Examples]

[0045] The following will provide a more detailed explanation using examples.

[0046] 1. Preparation of plasma-treated biomass Rice straw was prepared as plant biomass. Rice straw was added to a 20 mM NaOH aqueous solution to obtain a rice straw solution at a concentration of 1% (w / v). 5 mL of the rice straw solution was irradiated with glow plasma for 20 minutes to obtain a plasma-treated rice straw solution. An atmospheric pressure glow plasma device (manufactured by the Ito Laboratory, Meijo University, model number: AAGD, described in Vladislav Gamaleev, et al, Japanese Journal of Applied Physics, Applied Science 10, 801 (2020)) was used for plasma irradiation. The solution that evaporated due to plasma irradiation was adjusted to 5 mL by adding deionized water.

[0047] 2. Growth experiment of Arabidopsis thaliana The wild-type strain of Arabidopsis thaliana, Col-0 (Col-0), was used. Seed sterilization involved immersing the seeds in sterile seed water (1% sodium hypochlorite, 0.05% Triton X-100) for 5 minutes, followed by four washes with sterile water. To break dormancy, the seeds were subjected to a 2-day low-temperature treatment at 4°C in the dark. Afterward, they were sown in the following growing medium and cultivated in a growth chamber at 22°C under a white fluorescent light (light intensity: 30 μE / m²). 2 s) The plants were grown vertically under long-day conditions (16 hours light / 8 hours dark).

[0048] The growing medium composition was prepared as follows: A basic medium (-Fe medium) was prepared by adding 100 μM Ferrozine, 0.05% MES-KOH, and 1% sucrose to the Murashige and Skoog (MS) medium mixture salts shown in the table (storage solution 1; 1 / 50, storage solution 2; 1 / 100, storage solution 3; 1 / 100, storage solution 4; 1 / 100, storage solution 5; 1 / 200). Rice straw solution and plasma-treated rice straw solution were added to the basic medium (-Fe medium), and the pH was adjusted to 5.7 with 1N HCl solution. The amount of rice straw solution and plasma-treated rice straw solution added was adjusted so that the final concentration was 2.5% (v / v), i.e., the amount of plant biomass relative to the medium was 0.025% (w / v), or the final concentration was 7.5% (v / v), i.e., the amount of plant biomass relative to the medium was 0.075% (w / v). For the control, a 20 mM NaOH solution without rice straw was added to the same concentration and adjusted to pH 5.7. Then, plant growth agar was added to a final concentration of 1%, and the mixture was autoclaved at 121°C for 15 minutes and solidified in a plastic petri dish.

[0049] [Table 1]

[0050] (1) Weight of the above-ground portion The weight of the above-ground parts of control samples, 2.5% (v / v) rice straw solution samples, and 2.5% (v / v) plasma-treated rice straw solution samples was measured on day 21 of growth. For each of the two samples, the weight of the above-ground parts of 10 individuals was measured, and the average value was calculated. The results are shown in Figures 1 and 2. In the graph in Figure 2, "Control" represents the results for the control samples, "non" represents the results for the 2.5% (v / v) rice straw solution samples, and "plasma" represents the results for the 2.5% (v / v) plasma-treated rice straw solution samples. The vertical axis represents the weight of the above-ground parts (mg).

[0051] The weight of the above-ground portion in the control sample was 4.32 mg. In the 2.5% (v / v) rice straw solution sample, the weight of the above-ground portion was 10.77 mg. In the 2.5% (v / v) plasma-treated rice straw solution sample, the weight of the above-ground portion was 16.63 mg. These results suggest that the plasma-treated rice straw solution contributes to an increase in the weight of the above-ground portion.

[0052] (2) Observation of the roots The roots of samples treated with a 7.5% (v / v) rice straw solution and a 7.5% (v / v) plasma-treated rice straw solution were observed on day 7 and day 14 of growth. The results on day 7 and day 14 are shown in Figure 3, and the results on day 14 are shown in Figure 4.

[0053] The upper photographs in Figure 3 show the elongation of the taproots of samples in a 7.5% (v / v) rice straw solution (7.5% Inawara_No Plasma) and a 7.5% (v / v) plasma-treated rice straw solution (7.5% Inawara_with Plasma) on day 7 of growth. The white arrows in the photographs indicate the approximate position of the taproot tip. On day 7 of growth, the taproot length of the sample in the 7.5% (v / v) plasma-treated rice straw solution was about half the length of the taproot of the sample in the 7.5% (v / v) rice straw solution.

[0054] The lower photographs in Figure 3 show the elongation of the taproot and the appearance of root hairs in samples of 7.5% (v / v) rice straw solution (7.5% Inawara_No Plasma) and 7.5% (v / v) plasma-treated rice straw solution (7.5% Inawara_with Plasma) on day 14 of growth. On day 14 of growth, the taproot length of the sample of 7.5% (v / v) plasma-treated rice straw solution was shorter than that of the sample of 7.5% (v / v) rice straw solution. The root hairs of the sample of 7.5% (v / v) plasma-treated rice straw solution showed more accelerated growth than those of the sample of 7.5% (v / v) rice straw solution.

[0055] Figure 4 shows the root hairs of a control sample, a 7.5% (v / v) rice straw solution sample, and a 7.5% (v / v) plasma-treated rice straw solution sample at 14 days of growth. The root hairs of the 7.5% (v / v) plasma-treated rice straw solution sample showed accelerated growth compared to the control sample and the 7.5% (v / v) rice straw solution sample. This result suggests that plasma-treated rice straw solution contributes to the promotion of root hair growth.

[0056] (3) Presence or absence of chlorosis The presence or absence of chlorosis was checked on 14 days of growth for samples of 7.5% (v / v) rice straw solution and 7.5% (v / v) plasma-treated rice straw solution. The results on 14 days of growth are shown in the lower panel of Figure 3.

[0057] The lower photographs in Figure 3 show samples of 7.5% (v / v) rice straw solution (7.5% Inawara_No Plasma) and 7.5% (v / v) plasma-treated rice straw solution (7.5% Inawara_with Plasma) on day 14 of growth. Chlorosis was observed in three individuals of the 7.5% (v / v) rice straw solution sample. In the photograph, the three gray arrows near the text "Chlorosis Occurred" indicate the individuals in which chlorosis was observed. No chlorosis was observed in any of the individuals of the 7.5% (v / v) plasma-treated rice straw solution sample. This result suggests that plasma-treated rice straw solution contributes to the suppression of chlorosis.

[0058] (4) Gene expression analysis of Arabidopsis thaliana using quantitative PCR The above-ground parts and roots of Arabidopsis thaliana Col-0 strains, grown in plant growth medium for 21 days, were separated using a Surgical Blade 11 and collected in 1.5 mL RNAase-free round-bottom microcentrifuge tubes (RC0150). The tubes were then rapidly frozen in liquid nitrogen. The frozen samples were ground using a plastic pestle, and 100 μL of a solution of RLT buffer (provided with the RNeasy Mini kit (Qiagen)) mixed with 2 M dithiothreitol (DTT) at a 300:7 ratio was added to the ground samples. Subsequently, total RNA was extracted using the RNeasy Plant mini kit according to its protocol. The cDNA was diluted with RNase-free water to a total RNA concentration of 100 ng / μL, and reverse transcription was performed using ReverTraAce qPCR RT Master Mix with gDNA Remover (TOYOBO) according to its protocol to obtain a 10 μL cDNA pool. Using THUNDERBIRD SYBR qPCR Mix (TOYOBO), the obtained cDNA was diluted 2-fold and used as a template for RT-qPCR using the PCR Eco system (PCR max) under the conditions of 95°C for 1 minute, (95°C for 15 seconds, 60°C for 35 seconds) × 40 cycles. The expression levels of the target genes were corrected using the expression levels of the endogenous control PDF2 (At1g13320).

[0059] The expression level of MMT1 (auxin response), a gene related to the auxin response, was investigated. The expression levels of bHLH38 (iron response transcription factor), IRT1 (iron uptake transporter), and FRO2 (ferric iron reduction), genes related to the iron response, were also investigated. The results are shown in the graphs in Figure 6. The upper left graph in Figure 6 shows the expression level of MMT1. The upper right graph in Figure 6 shows the expression level of bHLH38. The lower left graph in Figure 6 shows the expression level of IRT1. The lower right graph in Figure 6 shows the expression level of FRO2. In the graphs in Figure 6, "shoot" represents the results for the above-ground part, and "root" represents the results for the roots. "con." represents the results for the control sample, "plasma" represents the results for the sample in a 7.5% (v / v) plasma-treated rice straw solution, and "non" represents the results for the sample in a 7.5% (v / v) rice straw solution. The vertical axis represents the expression level of each gene.

[0060] Samples of 7.5% (v / v) plasma-treated rice straw solution showed reduced expression of MMT1 (auxin response), IRT1 (iron uptake transporter), and FRO2 (ferric iron reduction) in the roots compared to the control sample and the 7.5% (v / v) rice straw solution sample. Samples of 7.5% (v / v) plasma-treated rice straw solution showed reduced expression of MMT1 (auxin response) and bHLH38 (iron response transcription factor) in the above-ground parts compared to the control sample and the 7.5% (v / v) rice straw solution sample. These results suggest that plants may recognize increased iron absorption in their roots after the addition of plasma-treated rice straw. Furthermore, the addition of plasma-treated rice straw may have increased the amount of iron transported to the above-ground parts of the plants. Additionally, it was found that the addition of plasma-treated rice straw reduced the auxin response.

[0061] 3. Experiment on the growth of E. coli LB medium was prepared with the following composition and autoclaved. Escherichia coli JM109 was pre-cultured in 5 mL of LB medium at 37°C and 100 rpm for 18 hours. [Table 2]

[0062] M9 medium (×10) was prepared with the composition shown below and autoclaved. [Table 3]

[0063] A plasma-treated rice straw solution or a culture medium containing a rice straw solution with the following composition is used to prepare a culture solution of pre-cultured E. coli (10 ml of sterile water). 4 10 μL of the bacterial solution (diluted twice) was added, and the main culture was performed. [Table 4]

[0064] E. coli was cultured at 37°C and 100 rpm in a culture medium to which plasma-treated rice straw solution or rice straw solution was added to achieve a final concentration of 0% (v / v) to 80% (v / v). The turbidity (OD600) of 100 μL of culture medium was measured using a 96-well plate at a wavelength of 600 nm with SpectraMax (Molecular Devices, San Jose, CA, USA). Measurements were taken 24, 48, 72, and 96 hours after incubation. The results are shown in the graph in Figure 6. In the graph in Figure 6, "Inawara_No Plasma" represents the results for samples with each final concentration of rice straw solution, and "Inawara_with Plasma" represents the results for samples with each final concentration of plasma-treated rice straw solution. A final concentration of 0% (v / v) represents the results for samples with neither plasma-treated rice straw solution nor rice straw solution added. In the graph in Figure 6, the horizontal axis represents the culture time (h), and the vertical axis represents the turbidity of the culture medium (OD600). The lower the turbidity (OD600), the fewer the number of E. coli bacteria.

[0065] As shown in the graph in Figure 6, the samples to which the plasma-treated rice straw solution was added had a turbidity (OD600) of approximately 0 at all concentrations, indicating almost no survival of E. coli. On the other hand, the samples to which the rice straw solution was added had a turbidity (OD600) of 0.1 or higher at all concentrations, indicating the growth of E. coli. These results confirm that plasma-treated rice straw has a bactericidal effect against E. coli.

[0066] 4. Effects of the Examples The above-described examples demonstrate that we have been able to provide a novel technology for the effective utilization of plant biomass.

[0067] The present invention is not limited to the embodiments detailed above, and various modifications or changes are possible within the scope of the claims of the present invention.

Claims

1. A plant composition containing plasma-treated biomass obtained by irradiating plant biomass with plasma.

2. The plant composition according to claim 1, for use in biostimulant materials.

3. The plant composition according to claim 1 or claim 2, wherein the plant biomass is the non-edible part of the plant.

4. A fungicide containing plasma-treated biomass obtained by irradiating plant biomass with plasma.

5. A fungicide according to claim 4, for use in plant cultivation.

6. A method for cultivating plants, comprising growing plants in a nutrient solution or soil containing plasma-treated biomass obtained by irradiating plant biomass with plasma.

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