Photoresponsive biostimulant for plants, aqueous dispersion for plants, and method for plant growth.

Abstract

To provide novel biostimulant materials for plants. [Solution] A photoresponsive biostimulant material for plants, characterized by containing a photocatalyst.

Description

[Technical Field]

[0001] This invention relates to a biostimulant material and aqueous dispersion for plants used to improve yield, quality, etc., in agriculture. [Background technology]

[0002] In agriculture, fertilizers and pesticides have long been used to improve yields, quality, and other aspects. Fertilizers and pesticides are typically used differently depending on the desired purpose. For example, fertilizers mainly containing nitrogen, phosphorus, and potassium are used to provide nutrients necessary for the healthy growth of crops (including trees and agricultural and forestry products; hereinafter referred to as "crops, etc."), while pesticides, such as fungi, nematodes, mites, insects, rodents, and other animals, plants, or viruses (diseases and pests) that harm crops, are used to directly control them.

[0003] Because fertilizers and pesticides are classified in detail according to the desired effect, it is necessary to change the type of fertilizer or pesticide each time to achieve the desired effect.

[0004] Therefore, in recent years, biostimulants have been attracting attention worldwide, particularly in Europe, as a new agricultural material to replace fertilizers and pesticides. Biostimulants are various substances and microorganisms that bring about better physiological conditions for plants and soil. The characteristic of biostimulants is that they have a positive effect on plants in terms of plant health, stress tolerance, yield and quality, post-harvest condition, and storage by utilizing the natural power inherent in plants and their surrounding environment.

[0005] Furthermore, the growing global interest in biostimulants stems from the global food crisis caused by population growth. Additionally, climate change due to global warming is drastically altering previously suitable environments, leading to unstable plant growth.

[0006] With limited arable land and the predicted harsher environment for plants, what is needed now is technology that allows for more efficient harvesting. Biostimulants, which enhance resistance to various environmental stresses and bring out the inherent potential of plants, are attracting attention for their effects such as alleviating abiotic stress, increasing plant nutrient uptake, and improving the physiological state of plants, and the market is currently expanding. Furthermore, the ideal is to achieve efficient harvesting on limited arable land, and various agricultural materials continue to be developed to achieve this.

[0007] Common biostimulants work by leveraging the natural abilities inherent in plants and their surrounding environment to positively influence plant health, stress tolerance, yield and quality, post-harvest condition, and storage. The mechanism by which plants develop strong stress tolerance generally involves a reaction with specific parts of the plant, improving those parts and thereby increasing tolerance to high temperatures, salt, drought, and other stressors, thus improving the overall condition of the plant.

[0008] As such a biostimulant, Patent Document 1 discloses a biostimulant composition comprising a microbial consortium of whole cells, wherein the consortium comprises at least 50% whole cells of gammaproteobacteria metanotroph. Patent Document 2 also discloses a plant biostimulant comprising inorganic and / or organic molecules containing one or more carbon atoms, biomass, amino acids, proteins, and / or vitamins produced via carbon fixation reactions or assimilation biosynthesis. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Special Publication No. 2023-572870 [Patent Document 2] Special Publication No. 2020-506708 [Overview of the project] [Problems that the invention aims to solve]

[0010] As increasingly harsh environments are predicted for plants in the future, the discovery of biostimulants with different mechanisms of action than those used before would allow for a diversification of responses to environmental changes.

[0011] Therefore, the object of the present invention is to provide a novel biostimulant material for plants. [Means for solving the problem]

[0012] The above problems are solved by the present invention as described below. In other words, the present invention (1) provides a photoresponsive biostimulant material for plants, characterized by containing a photocatalyst.

[0013] Furthermore, the present invention (2) provides the photoresponsive biostimulant material for plants according to (1), characterized in that the photocatalyst is an inorganic photocatalyst, an organic photocatalyst, or an organic-inorganic hybrid photocatalyst.

[0014] Furthermore, the present invention (3) provides a photoresponsive biostimulant material for plants according to (2), characterized in that the inorganic photocatalyst is one or more selected from the group consisting of titanium dioxide, zinc oxide, tungsten oxide, indium oxide, iron oxide, bismuth oxide, molybdenum sulfide, strontium titanate, silicon, gallium phosphide, gallium arsenide, cadmium sulfide, cadmium oxide, cadmium selenide, and silicon carbide.

[0015] Furthermore, the present invention (4) provides a photoresponsive biostimulant material for plants according to (2), characterized in that the organic photocatalyst is one or more selected from the group consisting of phthalocyanine compounds and their derivatives, metalloporphyrins, ruthenium complexes, and carbon nanotubes.

[0016] In addition, the present invention (5) provides a photoreactive biological stimulant material for plants (2), characterized in that the organic-inorganic hybrid photocatalyst is an organic-inorganic hybrid perovskite material.

[0017] In addition, the present invention (6) includes the biological stimulant material for plants (1), where the biological stimulant material for plants is dispersed in an aqueous solvent, and provides an aqueous dispersion for plants, characterized thereby.

[0018] In addition, the present invention (7) provides a method for growing plants, characterized in that the aqueous dispersion for plants (6) is sprayed on the plants.

Effects of the Invention

[0019] According to the present invention, a novel biological stimulant material for plants can be provided.

Modes for Carrying Out the Invention

[0020] The photoreactive biological stimulant material for plants of the present invention is a photoreactive biological stimulant material for plants, characterized by containing a photocatalyst.

[0021] The photoreactive biological stimulant material for plants of the present invention consists of a photocatalyst or is a composite or mixture of a photocatalyst and other components. In the present invention, the photoreactive biological stimulant material for plants refers to a material that generates active species from light energy when irradiated with ultraviolet light, visible light, infrared light such as sunlight or artificial lighting, and gives a favorable influence to plants by allowing the active species to act on the plants. That is, the photoreactive biological stimulant material for plants of the present invention is a material that can generate active species by light irradiation and give stimulation to plants existing in the vicinity by the generated active species, and is a material that gives a favorable influence to plants by such stimulation.

[0022] The photocatalyst related to the photoresponsive biostimulant material for plants of the present invention refers to a material that exhibits catalytic activity that changes the rate of chemical reactions when irradiated with light. When irradiated with ultraviolet light, visible light, infrared light, etc. from sunlight or artificial lighting, electrons and holes are created, which react with water, oxygen, etc. to generate reactive species such as hydroxyl radicals (·OH) and reactive oxygen species. In other words, a photocatalyst is a material that uses the energy of irradiated light to catalyze a reaction in which water, oxygen, etc. are converted into reactive species such as hydroxyl radicals and reactive oxygen species.

[0023] The photocatalyst for the photoresponsive plant biostimulant material of the present invention is not particularly limited as long as it can generate active species upon light irradiation and act on nearby plants, and examples include inorganic photocatalysts, organic photocatalysts, and organic-inorganic hybrid photocatalysts.

[0024] Examples of inorganic photocatalysts include titanium dioxide, zinc oxide, tungsten oxide, indium oxide, iron oxide, bismuth oxide, molybdenum sulfide, strontium titanate, silicon, gallium phosphide, gallium arsenide, cadmium sulfide, cadmium oxide, cadmium selenide, and silicon carbide.

[0025] There are two methods for producing titanium dioxide: the sulfuric acid method and the chlorine method. In the sulfuric acid method, the raw material (ilmenite ore) is dissolved in concentrated sulfuric acid, and the iron is separated as iron sulfate. The titanyl sulfate obtained in this process is hydrolyzed to obtain white hydrated titanium dioxide. After that, it is calcined to obtain titanium dioxide. In the chlorine method, higher-grade ore (such as natural rutile) is treated with coke and chlorine to produce titanium tetrachloride. This is heated to vaporize and reacted with oxygen at high temperature to obtain titanium dioxide. By recycling the separated chlorine, waste generation is reduced and the environmental burden is minimized. Other methods include the alkoxide method and the colloidal aerogel method.

[0026] Zinc oxide can be produced by heating and decomposing zinc oxalate or basic zinc carbonate in an oxidizing atmosphere. For example, one method involves adding an aqueous solution of zinc chloride or zinc nitrate dropwise to an aqueous solution of oxalate to precipitate fine crystals of zinc oxalate, filtering and drying them, and then heating and decomposing them to obtain zinc oxide. Another method involves adding an aqueous solution of sodium carbonate to an aqueous solution of zinc chloride to precipitate basic zinc carbonate, filtering and separating it, and then heating and decomposing it.

[0027] Inorganic photocatalysts are granular. The average particle size of the inorganic photocatalyst is not particularly limited, but is preferably 5 nm to 10 μm, more preferably 20 nm to 5 μm. In this invention, the average particle size of the inorganic photocatalyst is measured by methods such as the Beckman Coulter method, dynamic light scattering method, salt high transmission method, electrical detection method, laser diffraction / scattering method, and image analysis method.

[0028] Furthermore, in inorganic photocatalysts, a co-catalyst may be present at a position in contact with the inorganic material (fine particles) that originally has photocatalytic activity in order to broaden the absorption wavelength range. In other words, an inorganic photocatalyst may contain both a photocatalyst and a co-catalyst. An inorganic photocatalyst may include a photocatalyst such as titanium dioxide, zinc oxide, tungsten oxide, indium oxide, iron oxide, bismuth oxide, molybdenum sulfide, strontium titanate, silicon, gallium phosphide, gallium arsenide, cadmium sulfide, cadmium oxide, cadmium selenide, or silicon carbide, and a co-catalyst present in contact with the photocatalyst. The co-catalyst is not particularly limited as long as it functions as a co-catalyst for the photocatalyst, but metals such as silver (Ag), copper (Cu), nickel (Ni), gold (Au), platinum (Pt), palladium (Pd), rhodium (Rh), and ruthenium (Ru) are preferred.

[0029] One method for supporting a co-catalyst on an inorganic photocatalyst is to mix a metal nitrate such as silver (Ag), copper (Cu), or nickel (Ni), sodium citrate, iron sulfate, and pure water, centrifuge the mixture, and dilute the supernatant with pure water to create a metal colloidal dispersion. This solution can then be added to a suspension of titanium dioxide or zinc oxide powder and water, followed by drying and pulverization to obtain a powdered metal-supported photocatalyst. Alternatively, a metal salt of gold (Au), platinum (Pt), palladium (Pd), rhodium (Rh), or ruthenium (Ru), such as tetrachloroaurate tetrahydrate, hexachloroplatinate hexahydrate, palladium nitrate, rhodium chloride trihydrate, or ruthenium chloride trihydrate, can be dissolved in pure water, added to a suspension of titanium dioxide or zinc oxide, and the metal can be deposited while irradiating with UV light. The mixture can then be washed, dried, and pulverized to obtain an inorganic photocatalyst with a powdered co-catalyst supported.

[0030] Examples of organic photocatalysts include phthalocyanine compounds and their derivatives, metalloporphyrins, ruthenium complexes, and composites containing carbon nanotubes.

[0031] Phthalocyanine compounds are represented by the following formula (1):

[0032] [ka]

[0033] These are compounds having a phthalocyanine skeleton represented by formula (1). Phthalocyanine compounds have phthalocyanine or a phthalocyanine skeleton represented by formula (1) with -C(CH3)3, -NR2, -OR 35 -SR, SiR 3 -CF3, -SO2NR2, -COOH 46 These are compounds having substituents such as -SO3H and -CN (where R is a linear or branched hydrocarbon group, aromatic group, etc.). Examples of derivatives of phthalocyanine compounds include metal complexes of phthalocyanine compounds. Examples of metal species include Cu, Co, Ni, Zn, Sn, Pb, Fe, Mg, etc. Furthermore, derivatives of phthalocyanine compounds include those with the following formula:

[0034] [Chemical formula]

[0035] (In the formula, R is CH3.) A compound represented by the following formula:

[0036] [Chemical formula]

[0037] (In the formula, M is Zn 2+ , Cu 2+ and R is CH3, CH(CH3)2.) Examples of the compound represented thereby include.

[0038] Metalloporphyrin is a metal complex of a compound having a porphyrin skeleton represented by the following formula (2):

[0039] [Chemical formula]

[0040] It is a metal complex of a compound having a porphyrin skeleton represented by. The porphyrin compound is a compound having a substituent such as -C(CH3)3, -NR2, -OR 35 , -SR, SiR 3 , -CF3, -SO2NR2, -COOH 46 , -SO3H, -CN, etc. Examples of the metal species include Cu, Co, Ni, Zn, Sn, Pb, Fe, Mg, etc. Examples of derivatives of phthalocyanine-based compounds include the following formula:

[0041] [Chemical formula]

[0042] (In the formula, M is Cu 2+ , Ni 2+ , Co2+ (That is the case.) Examples of compounds represented by [the formula shown] are given.

[0043] Ruthenium complexes have ligands such as 2,2'-bipyridine (bpy), 2,2'-bipyridyl-4,4'-dicarboxylic acid (dcbpy), and cis-di(isothiocyanato)-bis(2,2'-bipyridyl-4,4'-dicarboxylic acid). When irradiated with ultraviolet light, visible light, or infrared light from sunlight or artificial lighting, electrons and holes are created, which react with water and oxygen to generate reactive species such as hydroxyl radicals (hydroxyl radicals (·OH)) and reactive oxygen species.

[0044] A composite containing carbon nanotubes refers to a composite of carbon nanotubes and silver iodate, silver iodide, TiO2, metal-supported TiO2, etc. When irradiated with ultraviolet light such as sunlight, visible light, or infrared light, electrons and holes are created, which react with water and oxygen to generate reactive species such as hydroxyl radicals (hydroxyl radicals (·OH)) and reactive oxygen species. The diameter of the carbon nanotubes is preferably 1 to 2.5 nm.

[0045] Organic-inorganic hybrid perovskite materials have an ABX3 structure in which an organic ammonium (RNH3) cation, an organic phosphonium (RPH3) cation, or an alkali metal cation is located at the A site, and a halide anion (Cl) is located at the X site. - , Br - , I - These materials have electrons and holes located within them, forming a perovskite structure. Organic-inorganic hybrid perovskite materials, when irradiated with ultraviolet light such as sunlight, visible light, or infrared light, create electrons and holes, which react with water and oxygen to generate reactive species such as hydroxyl radicals (hydroxyl radicals (·OH)) and reactive oxygen species.

[0046] The photoresponsive plant biostimulant of the present invention may contain a spreading agent. The spreading agent enhances the wettability, adhesion, spreadability, and suspension properties of the photoresponsive plant biostimulant, and has the function of uniformly adhering the photoresponsive plant biostimulant. In particular, when the photoresponsive plant biostimulant of the present invention is used by directly spraying it on plants and adhering it directly to the leaves, stems, etc., the plant is attached to the plant by spraying a dispersion of the photoresponsive plant biostimulant of the present invention in an aqueous solvent onto the plant. The spreading agent is used to ensure that the photoresponsive plant biostimulant of the present invention adheres uniformly to the plant surface at an appropriate density when the dispersion containing the photoresponsive plant biostimulant of the present invention is sprayed onto the plant.

[0047] As a spreading agent, there are no particular limitations as long as it can be used for agricultural purposes, and examples include nonionic surfactants, such as polyoxyethylene alkylphenyl ether surfactants, polyoxyethylene alkyl ether surfactants, polyalkylene glycol alkyl ether surfactants, polyoxyethylene fatty acid ester surfactants, polyoxyethylene resin acid ester surfactants, polyoxyethylene hexitane fatty acid ester surfactants, sorbitan fatty acid ester surfactants, and silicone surfactants as active ingredients; anionic surfactants, such as naphthylmethanesulfonate surfactants, ligninsulfonate surfactants, and alkylsulfosuccinate surfactants as active ingredients; and cationic surfactants, such as tetraalkylammonium salt surfactants. Examples of commercially available spreading agents include Approach BI (registered trademark, manufactured by Maruwa Biochemical Co., Ltd.), Squash (registered trademark, manufactured by Maruwa Biochemical Co., Ltd.), Surfactant WK (registered trademark, manufactured by Maruwa Biochemical Co., Ltd.), Mix Power (registered trademark, manufactured by Syngenta Japan Ltd.), Supply (registered trademark, manufactured by OAT Agrio Co., Ltd.), and Avion E (registered trademark, manufactured by Avion Co., Ltd.).

[0048] The content of the spreading agent in the photoresponsive plant biostimulant material of the present invention is appropriately selected, but for example, it is 0.10 to 40.0% by mass, preferably 0.10 to 25.0% by mass, and more preferably 1.0 to 20.0% by mass.

[0049] The photoresponsive plant biostimulant material of the present invention is a material that generates active species upon light irradiation and allows nearby plants to be stimulated by the generated active species, thereby having a beneficial effect on plants. Furthermore, by stimulating plants, the photoresponsive plant biostimulant material of the present invention can induce stress tolerance, for example, and promote plant growth and development throughout the entire crop lifecycle from seed germination to plant maturation in the following ways. The improved tolerance is illustrated below as an example. • Improve the efficiency of plant metabolism to promote increased yields and improved crop quality. • Strengthens and restores resistance to abiotic stress. • Promotes nutrient assimilation, translocation, and utilization. • To enhance the quality attributes of the product, such as sugar content and color. • Controls and improves the water balance of plants. More specific improvements include the suppression of reactive oxygen species, activation of photosynthesis, promotion of flowering and / or fruit setting, control of transpiration, and regulation of osmotic pressure, but these effects and improvements are not solely due to specific mechanisms.

[0050] Furthermore, the inventors have found that the light-responsive biostimulant material for plants of the present invention is a method of inducing new stress, and that the light-responsive biostimulant material for plants of the present invention enables the control of metabolites. Metabolism refers to the process by which living organisms synthesize compounds within the body in order to survive. The compounds produced in this process are called metabolites. Generally, it includes a series of reactions that utilize inorganic and organic substances taken in from the outside and convert them into compounds necessary for maintaining life through chemical reactions by enzymes, etc. Metabolism is broadly classified into anabolism and catabolism. Anabolism often involves energy absorption reactions and many reactions that synthesize molecules necessary for the construction of cells, and its main characteristic is the conversion from low molecular weight to high molecular weight. Metabolic pathways are intricately linked within living organisms, and changes in one pathway affect other pathways, resulting in a very complex structure. Since plants cannot move, they maintain homeostasis of essential metabolism and sustain life by regulating a series of metabolic pathways in response to stresses such as the growing environment, especially nutrient conditions of the atmosphere and soil, diseases, drought, and light. For example, in Arabidopsis thaliana, more than 500 biosynthetic pathways are known, but many mysteries remain regarding the regulation of each pathway.

[0051] Metabolism is broadly divided into primary and secondary metabolism. Primary metabolites are a general term for essential compounds directly involved in cell growth, development, and reproduction within plants. In the field of plant science, they refer to a group of metabolites that, when mutants are created that cannot produce them, exhibit a lethal phenotype. Major compounds include amino acids, sugars, sugar alcohols, nucleic acids, and organic acids. Plants assimilate nutrients such as hydrogen (H), carbon (C), oxygen (O), nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), sulfur (S), iron (Fe), silicon (Si), and boron (B) taken in from the atmosphere and soil, and convert them into organic compounds. Representative primary metabolic pathways include glycolysis, the citric acid cycle (TCA cycle), the pentose phosphate pathway, and the amino acid synthesis pathway. If the production capacity of primary metabolic pathways is lacking, lethal traits may be exhibited in the current or next generation, and they are greatly influenced by fluctuations in the external nutritional environment. For this reason, plants have adopted diverse evolutionary strategies. Examples include functional complementarity, the presence of isozymes with different cellular localizations, and intercellular transport of nutrients. Recent research has revealed that metabolic regulation and homeostasis through metabolic adaptive responses under nutrient deficiency conditions are crucial.

[0052] Secondary metabolites include plant hormones. Plant hormones are physiologically active substances that regulate plant growth and function as signaling molecules. A general definition of plant hormones is that they are 1) compounds produced within the plant, 2) act within or on the plant in trace amounts, 3) are widely present in plant species, and 4) the chemical structure and physiological effects of the active substance are known. To date, auxin, gibberellin, abscisic acid, ethylene, cytokinin, brassinosteroids, jasmonic acid, salicylic acid, and strigolactone are recognized as low-molecular-weight plant hormones. In addition, short-chain peptides with cell differentiation and proliferation-inducing effects, such as phytosulfokines and CLAVATA3, and proteins such as florigen that regulate flowering are also included in plant hormones. Mutants lacking plant hormone production are often known to be lethal or exhibit abnormal traits and development during the growth process. Furthermore, it has been reported that direct treatment with plant hormones induces various phenotypes, including growth, development / senescence, and metabolite production.

[0053] Secondary metabolites, also known as plant-specific metabolites, are a general term for plant species-specific metabolites among a group of compounds with diverse structures found in nature. While primary metabolites are essential for plant cell growth, development, and reproduction, secondary metabolites are considered to be compounds involved in other survival strategies. Many secondary metabolites possess biological activity and play an important role in plant defense against infection, interspecies competition, and coping with environmental stresses such as drought and strong light. The large number of plant species-specific compounds is a result of plants adapting to evolutionary pressures by producing various secondary metabolites in response to their environment. These compounds are often used as medicines, health-promoting substances, and fragrances. Representative secondary metabolic pathways include the flavonoid biosynthesis pathway, the glucosinolate biosynthesis pathway, and the alkaloid biosynthesis pathway.

[0054] The photoresponsive biostimulant material for plants of the present invention has the function of controlling the amount of metabolites of these primary and / or secondary metabolites.

[0055] One method of using the photoresponsive plant biostimulant material of the present invention is to form the photoresponsive plant biostimulant material of the present invention into granules and then scatter the granular photoresponsive plant biostimulant material of the present invention onto plants. When scattering the granular photoresponsive plant biostimulant material of the present invention onto plants, the average particle size of the photoresponsive plant biostimulant material of the present invention is not particularly limited, but is preferably 0.001 to 5.0 mm, and more preferably 0.01 to 1.0 mm, in terms of ease of handling.

[0056] One method of using the photoresponsive plant biostimulant material of the present invention is to disperse the photoresponsive plant biostimulant material of the present invention in an aqueous solvent, and then spray the resulting dispersion directly onto a plant to allow the photoresponsive plant biostimulant material of the present invention to adhere to the surface of the plant, such as the leaves and stems. When the photoresponsive plant biostimulant material of the present invention, dispersed in an aqueous solvent, is sprayed directly onto a plant, the dispersion to be sprayed, i.e., the aqueous plant dispersion of the present invention, contains the plant biostimulant material of the present invention, and is characterized in that the plant biostimulant material of the present invention is dispersed in an aqueous solvent. Furthermore, the plant growth method of the present invention is characterized by spraying a plant aqueous dispersion containing the plant biostimulant of the present invention, in which the plant biostimulant is dispersed in an aqueous solvent, that is, spraying the plant aqueous dispersion of the present invention onto a plant.

[0057] The plant biostimulant material of the present invention contained in the aqueous dispersion for plants of the present invention preferably contains 0.10 to 40.0% by mass of a spreading agent, more preferably 0.10 to 25.0% by mass of a spreading agent, and more preferably 1.0 to 20.0% by mass of a spreading agent. Because the plant biostimulant material of the present invention contained in the aqueous dispersion for plants of the present invention contains a spreading agent within the above range, by spraying the aqueous dispersion for plants of the present invention directly onto plants, the plant biostimulant material contained therein can be uniformly attached to the surface of the plants at an appropriate density.

[0058] The average particle size of the plant biostimulant material of the present invention contained in the aqueous dispersion for plants of the present invention is not particularly limited as long as it is small enough to be dispersed in an aqueous solvent, but is preferably 0.001 to 5.0 mm, and more preferably 0.01 to 1.0 mm. Having the average particle size of the plant biostimulant material of the present invention contained in the aqueous dispersion for plants of the present invention within the above range enables uniform dispensing.

[0059] The aqueous solvent used in the aqueous dispersion for plants of the present invention includes water and mixed solvents of water and aqueous alcohol. Examples of aqueous alcohols used as aqueous solvents include methanol, ethanol, isopropanol, and glycols.

[0060] The content of the plant biostimulant material of the present invention in the aqueous dispersion for plants of the present invention is not particularly limited, but is, for example, 0.05 to 10.0% by mass, preferably 0.1 to 1.0% by mass.

[0061] The aqueous dispersion for plants of the present invention may optionally contain regulators, solvents, emulsifiers, preservatives, antioxidants, fragrances, dyes, pigments, stabilizers, and the like. [Examples]

[0062] The plant biostimulant material of the present invention will be described below with reference to examples. However, the present invention is not limited to these embodiments.

[0063] (Example 1) <Biostimulant materials for plants> As a photocatalyst, rutile-type titanium dioxide (product code STS-427, manufactured by Ishihara Sangyo Co., Ltd.) with an average particle size of 0.085 μm was mixed with Approach BI (registered trademark, manufactured by Maruwa Biochemical Co., Ltd.) as a spreading agent to obtain a biostimulant material for plants. <Preparation of aqueous dispersion for plants> Next, the obtained plant biostimulant material was dispersed in water to obtain an aqueous plant dispersion with a solid content concentration of 1.0% by mass.

[0064] (Comparative Example 1) <Silica particles> A comparative material was obtained by mixing silica with an average particle size of 0.040 μm (product number PL-1M, manufactured by Fuso Chemical Industries, Ltd.) with Approach BI as a spreading agent. <Preparation of aqueous dispersion for plants> Next, the obtained comparative materials were dispersed in water to obtain an aqueous dispersion with a solid content concentration of 1.0% by mass.

[0065] <Rating 1> Spinach was used as the target plant to confirm its heat tolerance. A hydroponic system manufactured by UING was used. This system is equipped with white LEDs and UV light. Sufficient water was provided beneath the plants, and seedlings were placed in this system. Eight spinach seedlings were sprayed 10 times (10 mL) of a plant-based aqueous dispersion on days 1 and 8. From day 10, the temperature was increased from 24°C to 28°C, and the spinach was harvested on day 21. The fresh weight of the harvested spinach was measured.

[0066] <Rating 2> The amount of anthocyanins produced was confirmed using butterfly pea as the target plant. Butterfly peas were planted in a soil-based field, sprayed once (50 mL) with an aqueous plant dispersion, and the amount of anthocyanins was measured after 5 and 10 days.

[0067] <Results of Evaluation 1> As a result, compared to Comparative Example 1, which was sprayed with silica fine particles, Example 1 showed a weight increase of more than 10%.

[0068] <Results of Evaluation 2> In Example 1, the anthocyanin content after 5 days was 0.130 mg / g, and after 10 days it was 0.331 mg / g. In Comparative Example 1, the anthocyanin level after 5 days was 0.098 mg / g, and after 10 days it was 0.262 mg / g.

[0069] (Comparative Example 2) As a blank test, Comparative Example 2 was performed by spraying distilled water. <Results of Evaluation 1> The evaluation was carried out in the same manner as in Example 1, except that distilled water was used instead of an aqueous dispersion. As a result, the weight increase was about the same as in Comparative Example 1. <Results of Evaluation 2> The evaluation was carried out in the same manner as in Example 1, except that distilled water was used instead of an aqueous dispersion. As a result, the anthocyanin level after 5 days was 0.111 mg / g, and after 10 days it was 0.226 mg / g.

[0070] In Evaluation 1, Example 1 showed a weight increase of 10% or more compared to Comparative Example 1. Furthermore, in Evaluation 2, Example 1 showed an increase of 25% or more in anthocyanin content compared to Comparative Example 1. These results indicate that the plant biostimulant material of the present invention has a positive effect on plant growth through the action of photocatalysis. Additionally, it was found that the plant biostimulant material of the present invention can increase the production of secondary metabolites in plants through the action of photocatalysis.

Claims

1. A photoresponsive biostimulant material for plants, characterized by containing a photocatalyst.

2. The photo-responsive biostimulant material for plants according to claim 1, characterized in that the photocatalyst is an inorganic photocatalyst, an organic photocatalyst, or an organic-inorganic hybrid photocatalyst.

3. The photoresponsive biostimulant material for plants according to claim 2, characterized in that the inorganic photocatalyst is one or more selected from the group consisting of titanium dioxide, zinc oxide, tungsten oxide, indium oxide, iron oxide, bismuth oxide, molybdenum sulfide, strontium titanate, silicon, gallium phosphide, gallium arsenide, cadmium sulfide, cadmium oxide, cadmium selenide, and silicon carbide.

4. The photoresponsive biostimulant material for plants according to claim 2, characterized in that the organic photocatalyst is one or more selected from the group consisting of phthalocyanine compounds and their derivatives, metalloporphyrins, ruthenium complexes, and carbon nanotubes.

5. The photoresponsive biostimulant material for plants according to claim 2, characterized in that the organic-inorganic hybrid photocatalyst is an organic-inorganic hybrid perovskite material.

6. The plant biostimulant material described in claim 1 comprises, The plant biostimulant material is dispersed in an aqueous solvent. A plant-based aqueous dispersion characterized by the following features.

7. A method for growing plants, characterized by spraying the aqueous dispersion for plants described in claim 6 onto the plants.

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