Growth improving composition for plant

Abstract

To provide a growth improving composition for plant which contains organism stimulant, uses water as solvent or dispersion medium, and has high effect of accelerating growth of a plant.SOLUTION: A growth improving composition for plant contains organism stimulant which alleviates non-biological stress of a plant or accelerates growth of a plant, biodegradable surfactant and water, where the content of the biodegradable surfactant is 0.008 to 0.150 mass% based on active ingredient.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a composition for improving plant growth for growing plants healthily.

Background Art

[0002] It is known that spraying an aqueous solution containing zerumbone as a main component on plants makes them resistant to high temperature and salt stress and has the effect of promoting plant growth. For example, Patent Document 1 discloses a stress-relieving and growth-promoting agent for plants that contains zerumbone as a main component, relieves environmental stress on plants, and promotes plant growth.

[0003] Such a composition for improving plant growth is used by directly spraying it on the leaves of plants. However, the leaf surface is likely to repel the formulation. And although zerumbone exerts a growth-promoting effect by penetrating from the leaf surface into the leaves, if the leaf surface repels the formulation, there is a risk that the formulation will fall off the leaf surface before zerumbone penetrates into the leaves.

[0004] In order to prevent repulsion from the leaf surface, a surfactant may be added. For example, Patent Document 2 discloses containing a compatible surfactant as necessary in a plant activator that can be sprayed on the stems and leaves of plants.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] When spraying an aqueous solution containing zerumbone as a main component on plants, it is desirable that the added surfactant does not inhibit the penetration of the formulation into the leaves and contributes to plant growth. However, Patent Document 2 does not clarify the significant difference in the effect of promoting plant growth by adding a surfactant.

[0007] Therefore, an object of the present invention is to provide a plant growth promotion composition containing a biostimulant and using water as a solvent or dispersion medium, which has a high effect of promoting plant growth.

Means for Solving the Problems

[0008] As a result of intensive research, the present inventors have found that in a plant growth promotion composition in which a biostimulant that alleviates abiotic stress of plants or promotes plant growth is dissolved or dispersed in water, by using a biodegradable surfactant and setting the addition amount of the biodegradable surfactant to water at a predetermined amount, the adhesion of the plant growth promotion composition to the leaf surface is improved, and thereby the permeability of the biostimulant into the plant is improved and the growth promotion effect is enhanced, and the present invention has been completed.

[0009] That is, the present invention (1) contains a biostimulant that alleviates abiotic stress of plants or promotes plant growth, a biodegradable surfactant, and water, wherein the content of the biodegradable surfactant is 0.008 to 0.150% by mass based on the active ingredient, and is a plant growth promotion composition characterized by the above.

[0010] The present invention (2) is a composition for improving the growth of plants according to (1), characterized in that the biostimulant is at least one selected from the group consisting of zerumbone, analogs of zerumbone, derivatives of zerumbone, salts of zerumbone, salts of analogs of zerumbone, salts of derivatives of zerumbone, salicylic acid, polyamines, geldanamycin, trimethylglycine, perillaldehyde, citral, carotenes, lycopene, zeaxanthin, cryptoxanthin, lutein, phenylethyl isothiocyanate, ursolic acid, choline, alginic acid, fulvic acid, humic acid, 5-aminolevulinic acid, oxidized glutathione, trehalose, and 2-hexanal.

[0011] The present invention (3) is a composition for improving the growth of plants according to (1) or (2), characterized in that the biodegradable surfactant is a biosurfactant.

[0012] The present invention (4) is a composition for improving the growth of plants according to (1) or (2), characterized in that the biodegradable surfactant is at least one selected from the group consisting of sugar-based biosurfactants, lipopeptide-based biosurfactants, and fatty acid-based biosurfactants.

[0013] The present invention (5) is a composition for improving the growth of plants according to (1) or (2), characterized in that the biodegradable surfactant is at least one selected from the group consisting of sophorolipid, mannosylerythritol lipid, rhamnolipid, trehalose lipid, cellobiose lipid, rhamosin, surfactin, and spiculisporic acid.

Advantages of the Invention

[0014] According to the present invention, there can be provided a composition for improving the growth of plants, which contains a biostimulant and uses water as a solvent or dispersion medium, and has a high effect of promoting the growth of plants.

Embodiments for Carrying Out the Invention

[0015] The composition for improving the growth of plants of the present invention is A biostimulant that alleviates abiotic stress in plants or promotes plant growth, a biodegradable surfactant, and water, wherein the content of the biodegradable surfactant is 0.008 to 0.150% by mass based on the active ingredient, and it is a composition for improving plant growth, characterized by the above.

[0016] The composition for improving plant growth of the present invention contains a biostimulant (also called a biostimulant) that alleviates abiotic stress in plants or promotes plant growth. That is, in the composition for improving plant growth of the present invention, the biostimulant is dissolved or dispersed in water and formulated.

[0017] Biostimulants (biostimulants) are new agricultural materials that have recently attracted attention around the world, mainly in Europe. Biostimulants are various substances and microorganisms that bring about a better physiological state to plants and soil. The characteristic of biostimulants is to utilize the natural power inherent in plants and their surrounding environment to have a good influence on plants in terms of plant health, stress tolerance, yield and quality, post-harvest state, and storage.

[0018] A biostimulant is a substance or microorganism that, when provided to plants, acts to alleviate abiotic stress (environmental stress), enhance the ability of plants to take up nutrients, promote plant growth, and improve the physiological state of plants, thereby alleviating abiotic stress or promoting plant growth. Abiotic stress (environmental stress) includes heat stress, high humidity stress, salt stress, drought stress, cold stress, frost stress, oxidative stress (damage by reactive oxygen species), physical damage (such as damage by hail or wind), stress caused by phytotoxicity due to pesticides, etc. The biostimulant helps plant growth by alleviating these abiotic stresses (environmental stresses). In addition, the biostimulant enhances the ability of plants to take up nutrients and promotes plant growth, for example, by improving the rhizosphere environment such as promoting the growth of soil microorganisms, stabilizing rhizobia, increasing the root mass, improving root activity, inducing hormones that regulate the opening and closing of stomata, and improving drought tolerance. Further, the biostimulant improves the physiological state of plants and alleviates abiotic stress or promotes plant growth by activating photosynthesis, promoting flowering or fruit setting, controlling transpiration, adjusting osmotic pressure, synthesizing starch that aphids dislike, etc. And the biostimulant contributes to the improvement of yield, quality, etc. by acting to alleviate abiotic stress, enhance the ability of plants to take up nutrients, and improve the physiological state of plants. Note that the biostimulant acts on at least one of "alleviating abiotic stress", "enhancing the ability of plants to take up nutrients", and "improving the physiological state of plants". Depending on the type of biostimulant, there are those that are excellent at exerting one or two of these three actions, and those that exert all three of these actions.

[0019] The biostimulant according to the plant growth promoting composition of the present invention is preferably absorbed from the stomata of plant leaves to alleviate abiotic stress of plants or promote plant growth.

[0020] Examples of the biostimulant include compounds that induce heat shock proteins. Examples of the compounds that induce heat shock proteins include zerumbone, analogs of zerumbone, derivatives of zerumbone, salts of zerumbone, salts of analogs of zerumbone, salts of derivatives of zerumbone, salicylic acid, polyamine, geldanamycin, trimethylglycine, perillaldehyde, citral, carotene, lycopene, zeaxanthin, cryptoxanthin, lutein, phenylethyl isothiocyanate, ursolic acid, choline, alginic acid, fulvic acid, humic acid, 5-aminolevulinic acid, oxidized glutathione, trehalose, and 2-hexanal. The biostimulant of the plant growth promoting composition of the present invention can be at least one selected from the group consisting of zerumbone, analogs of zerumbone, derivatives of zerumbone, salts of zerumbone, salts of analogs of zerumbone, salts of derivatives of zerumbone, salicylic acid, polyamine, geldanamycin, trimethylglycine, perillaldehyde, citral, carotene, lycopene, zeaxanthin, cryptoxanthin, lutein, phenylethyl isothiocyanate, ursolic acid, choline, alginic acid, fulvic acid, humic acid, 5-aminolevulinic acid, oxidized glutathione, trehalose, and 2-hexanal.

[0021] Heat shock proteins are produced when cells are stressed, bind to denatured proteins, and play a role in repairing denatured proteins. Compounds that induce heat shock proteins induce the generation of heat shock proteins, thereby improving stress tolerance. That is, compounds that induce heat shock proteins act effectively in alleviating environmental stresses such as high-temperature stress, high-humidity stress, salt stress, and drought stress. Zerumbone, salicylic acid, polyamine, geldanamycin, trimethylglycine, perillaldehyde, citral, carotene, lycopene, zeaxanthin, cryptoxanthin, lutein, phenylethyl isothiocyanate, ursolic acid, choline, alginic acid, fulvic acid, humic acid, 5-aminolevulinic acid, oxidized glutathione, trehalose, 2-hexanal, etc. are known to induce heat shock proteins.

[0022] For example, when heat shock is applied to plant cells, heat shock factors are activated in the cytoplasm of plant cells and separated into HSP70 (heat shock protein), HSP90 (heat shock protein), and HSF (heat shock factor). HSFs bind to form subunits with a predetermined three-dimensional structure and translocate into the nucleus to bind to the HSE sequence of the plant genome. The binding of this HSF subunit to the HSE sequence switches on related genes to counter heat shock. Specifically, it can produce heat shock proteins to repair damaged proteins, produce antibacterial substances (antibacterial proteins) to prevent infection by pathogenic bacteria, or produce proteins that remove reactive oxygen species to eliminate reactive oxygen species. This improves the tolerance to environmental stress.

[0023] Then, the compound that induces heat shock protein acts on plant cells to produce HSF. The produced HSFs bind to each other to form subunits with a predetermined three-dimensional structure, and then translocate into the nucleus and bind to the HSE sequence of the plant genome. The binding of this HSF subunit to the HSE sequence switches on the related genes for combating heat shock, thereby producing heat shock protein. Thus, the compound that induces heat shock protein is taken up by plant cells to induce the production of heat shock protein.

[0024] Examples of heat shock proteins include heat shock protein 40, heat shock protein 70, heat shock protein 32, heat shock protein 47, heat shock protein 60, etc. And the compound that induces heat shock protein induces heat shock protein in the same way as when exposed to a high-temperature environment.

[0025] In the composition for improving plant growth of the present invention, the compound that induces heat shock protein is dissolved or dispersed in water. The composition for improving plant growth of the present invention is produced, for example, by adding a formulation agent in which a compound that induces heat shock protein is dissolved or dispersed in water with water used as a solvent or dispersion medium as an active ingredient. Commercially available products of such formulation agents containing a compound that induces heat shock protein as an active ingredient include Thermozyme (registered trademark), Suzumidori (registered trademark), SKEEPON (registered trademark), etc.

[0026] The content of the compound that induces heat shock protein in the composition for improving plant growth of the present invention is not particularly limited and is appropriately selected. However, based on the active ingredient standard, that is, based on the compound that induces heat shock protein, it is preferably 0.05 to 0.30% by mass, more preferably 0.08 to 0.20% by mass.

[0027] Examples of the biostimulant include zerumbone, analogs of zerumbone, derivatives of zerumbone, salts of zerumbone, salts of analogs of zerumbone, and salts of derivatives of zerumbone. Zerumbone (6CI, 7CI) is (2E, 6E, 10E)-2,6,9,9-tetramethylcycloundeca-2,6,10-trien-1-one (Empirical Formula (Hill Notation): C 15 H 22 O, CAS Registry Number: 471-05-6), and is represented by the following formula (1).

[0028]

Chemical Formula

[0029] Zerumbone is a sesquiterpene and a type of cyclic sesquiterpene. Zerumbone can be obtained as an extract or a ground product from plants of the Zingiberaceae family such as ginger and turmeric. Alternatively, it can also be obtained as an extract or a ground product of hops, cloves, or lavender. Since zerumbone is a natural product contained in edible plants, it has high safety. For example, the essential oil component of Alpinia zerumbet contains 80 to 90% by mass of zerumbone. An extract from the essential oil component of Alpinia zerumbet can be mainly used, or a ground product can also be used.

[0030] Analogs exhibit similar properties because they have similar molecular biological properties and structures such as receptor binding characteristics. However, they are another compound with a composition in which an atom or atomic group of a certain compound is replaced by another atom or atomic group. Examples of analogs of zerumbone include α-humulene:

[0031]

Chemical Formula

[0032] β-caryophyllene:

[0033]

Chemical Formula

[0034] Germacrene D:

[0035]

Chem.

[0036] Caryophyllene oxide:

[0037]

Chem.

[0038] Cobson:

[0039]

Chem.

[0040] Examples include. Salts of zerumbone, salts of analogs of zerumbone, and salts of derivatives of zerumbone are not particularly limited, and examples thereof include inorganic acid salts such as carbonates, hydrochlorides, nitrates, sulfates, and phosphates, and organic acid salts such as acetates, propionates, butyrates, and other aliphatic acid salts. Zerumbone, analogs of zerumbone, derivatives of zerumbone, salts of zerumbone, salts of analogs of zerumbone, and salts of derivatives of zerumbone effectively act to relieve environmental stresses such as high temperature stress, high humidity stress, salt stress, and drought stress.

[0041] In the plant growth promoting composition of the present invention, zerumbone, analogs of zerumbone, derivatives of zerumbone, salts of zerumbone, salts of analogs of zerumbone, and salts of derivatives of zerumbone are dissolved or dispersed in water. The plant growth promoting composition of the present invention is produced, for example, by adding a formulation containing zerumbone, an analog of zerumbone, a derivative of zerumbone, a salt of zerumbone, a salt of an analog of zerumbone, or a salt of a derivative of zerumbone as an active ingredient to water used as a solvent or dispersion medium. Examples of such formulations containing zerumbone, an analog of zerumbone, a derivative of zerumbone, a salt of zerumbone, a salt of an analog of zerumbone, and / or a salt of a derivative of zerumbone as an active ingredient include Stress Free Z (registered trademark) (manufactured by Fuso Chemical Industry Co., Ltd.) and Stress Free HE (registered trademark) (manufactured by Fuso Chemical Industry).

[0042] The content of zerumbone, analogs of zerumbone, derivatives of zerumbone, salts of zerumbone, salts of analogs of zerumbone, and salts of derivatives of zerumbone in the plant growth promoting composition of the present invention is not particularly limited and is appropriately selected. However, based on the active ingredient, it is preferably 0.05 to 0.30% by mass, more preferably 0.08 to 0.20% by mass. When the plant growth promoting composition of the present invention contains, as a biostimulant, one selected from the group consisting of zerumbone, analogs of zerumbone, derivatives of zerumbone, salts of zerumbone, salts of analogs of zerumbone, and salts of derivatives of zerumbone, the amount of the active ingredient refers to the content of that one. When the plant growth promoting composition of the present invention contains two or more selected from the group consisting of zerumbone, analogs of zerumbone, derivatives of zerumbone, salts of zerumbone, salts of analogs of zerumbone, and salts of derivatives of zerumbone, it refers to the total of those zerumbone, analogs of zerumbone, derivatives of zerumbone, salts of zerumbone, salts of analogs of zerumbone, and salts of derivatives of zerumbone.

[0043] Examples of the biostimulant include glycine betaine (also called trimethylglycine), derivatives of glycine betaine, salts of glycine betaine, and salts of derivatives of glycine betaine. The salts of glycine betaine are not particularly limited, and examples thereof include inorganic acid salts such as carbonate, hydrochloride, nitrate, sulfate, and phosphate, and organic acid salts such as acetate, propionate, butyrate, and other aliphatic acid salts. Glycine betaine, derivatives of glycine betaine, salts of glycine betaine, and salts of derivatives of glycine betaine effectively act to alleviate environmental stresses such as high-temperature stress, high-humidity stress, salt stress, and drought stress.

[0044] In the composition for improving plant growth of the present invention, glycine betaine, derivatives of glycine betaine, salts of glycine betaine, and salts of derivatives of glycine betaine are dissolved or dispersed in water. The composition for improving plant growth of the present invention is produced, for example, by adding a formulation containing glycine betaine, derivatives of glycine betaine, salts of glycine betaine, and salts of derivatives of glycine betaine as active ingredients to water used as a solvent or a dispersion medium. Examples of such a formulation containing glycine betaine, derivatives of glycine betaine, salts of glycine betaine, and / or salts of derivatives of glycine betaine as active ingredients include Sakata liquid fertilizer GB (manufactured by Sakata Seed Corporation).

[0045] The content of glycine betaine, derivatives of glycine betaine, salts of glycine betaine, and salts of derivatives of glycine betaine in the composition for improving plant growth of the present invention is not particularly limited and is appropriately selected. However, based on the active ingredient, it is preferably 0.05 to 0.30% by mass, more preferably 0.08 to 0.20% by mass. When the composition for improving plant growth of the present invention contains, as a biostimulant, one selected from the group consisting of glycine betaine, derivatives of glycine betaine, salts of glycine betaine, and salts of derivatives of glycine betaine, the amount of the active ingredient refers to the content of that one kind. Also, when it contains two or more selected from the group consisting of glycine betaine, derivatives of glycine betaine, salts of glycine betaine, and salts of derivatives of glycine betaine, it refers to the total of those glycine betaine, derivatives of glycine betaine, salts of glycine betaine, and salts of derivatives of glycine betaine.

[0046] Examples of biostimulants include amino acids such as choline, alginic acid, fulvic acid, humic acid, and 5-aminolevulinic acid. For example, fulvic acid effectively acts to improve the nutrient absorption capacity of plants. Choline has a high absorption rate by plants and effectively acts for prompt nutrient supply. Amino acids are necessary for synthesizing proteins required for growth and can support the growth of plants even in situations where photosynthesis cannot occur. Commercially available products containing these compounds as active ingredients include Liquidus (registered trademark) (manufactured by Hyponex Corporation), Morning Fresh (registered trademark) (manufactured by Agro Kanesho Co., Ltd.), High Tack C (registered trademark) (manufactured by Agro Kanesho Co., Ltd.), Atnic (registered trademark) (manufactured by Asahi Chemical Industry Co., Ltd.), Revital (manufactured by OAT Agrio Co., Ltd.), Fulvo Body (registered trademark) (manufactured by OAT Agrio Co., Ltd.), ALA-FeSTA (registered trademark) (manufactured by Sakata Seed Corporation), Pentakeep (registered trademark) (manufactured by Seiwa Co., Ltd.), Azu Liquid (manufactured by Denka Co., Ltd.), Azomin (registered trademark) (manufactured by Denka Co., Ltd.), Bombardia (manufactured by Hyponex Japan Co., Ltd.), Phyt-Otsu (Phytochrome), Tool Dry Soluble (manufactured by Bike Chemical Japan Co., Ltd.), Organmin DA (registered trademark) (manufactured by Parsar International Co., Ltd.), Soil Power Element (registered trademark) (manufactured by PII Bio Co., Ltd.), Royal Humic Acid Granules (registered trademark) (manufactured by Royal Industries Co., Ltd.), and the like. The contents of choline, 5-aminolevulinic acid, alginic acid, fulvic acid, humic acid, and amino acids in the plant growth promoting composition of the present invention are not particularly limited and are appropriately selected, but are preferably 0.05 to 0.30% by mass, more preferably 0.08 to 0.20% by mass based on the active ingredient standard. When the plant growth promoting composition of the present invention contains two or more biostimulants, the amount of the active ingredient refers to the total thereof. In the plant growth promoting composition of the present invention, these biostimulants are dissolved or dispersed in water.

[0047] Examples of biostimulants include oxidized glutathione, trehalose, 2-hexanal, and the like. Oxidized glutathione, trehalose, and 2-hexanal effectively act to alleviate environmental stress.

[0048] Examples of commercially available biostimulants or formulations containing a biostimulant as an active ingredient include, for example, Tetsu-ryoku Agu-ri (registered trademark, manufactured by Aichi Steel Works, Ltd.) containing iron as an active ingredient, Tetsu-ryoku Treplus (manufactured by Aichi Steel Works, Ltd.); Harmonzyme (registered trademark, manufactured by Alice Life Sciences Co., Ltd.) containing corn extract as an active ingredient; Algamix (registered trademark, manufactured by OAT Agrio Co., Ltd.), Kelpak 66 (registered trademark, manufactured by Royal Industries Co., Ltd.) containing seaweed extract as an active ingredient; Kaneka Peptide (registered trademark, manufactured by Kaneka Corporation), Kaneka Fertilizer (manufactured by Kaneka Corporation) containing oxidized glutathione as an active ingredient; Sunnonic (registered trademark, manufactured by Sanyo Chemical Industries, Ltd.) containing a surfactant as an active ingredient; Oxo Power 5 (registered trademark, manufactured by Takii Seed Co., Ltd.), MOX (registered trademark, manufactured by Hodogaya Chemical Co., Ltd.), Neo Cal Oxo (registered trademark, manufactured by Hodogaya Chemical Co., Ltd.) containing an oxygen supplier as an active ingredient; a formulation (manufactured by Hayashibara Co., Ltd.) containing trehalose as an active ingredient; Suzumidori (registered trademark, manufactured by Phytocrome Co., Ltd.) containing 2-hexanal as an active ingredient; Mida 31 (registered trademark, manufactured by Mida Fermentation Co., Ltd.) containing plant materials as an active ingredient; Agri Revolution (registered trademark, manufactured by Menicon Co., Ltd.) containing a plant fiber-degrading enzyme as an active ingredient; Takii Trace (registered trademark, manufactured by Takii Seed Co., Ltd.) containing trehalose as an active ingredient, and the like. The content of these in the plant growth promoting composition of the present invention is not particularly limited and is appropriately selected, but based on the active ingredient, it is preferably 0.05 to 0.30% by mass, more preferably 0.08 to 0.20% by mass. When the plant growth promoting composition of the present invention contains two or more biostimulants, the amount of the active ingredient refers to the total thereof. In the plant growth promoting composition of the present invention, these biostimulants are dissolved or dispersed in water.

[0049] The plant growth promoting composition of the present invention contains a biodegradable surfactant. That is, in the plant growth promoting composition of the present invention, the biodegradable surfactant is dispersed and blended in water. The inventors of the present invention have found that, since the biodegradable surfactant has a molecular structure or bond with high affinity for the surface of plants such as the leaf surface of plants, compared with petroleum-derived surfactants (synthetic surfactants synthesized using petroleum-derived raw materials), the affinity of the plant growth promoting composition using water as a solvent or dispersion medium for the surface of plants can be increased. Therefore, by including a biodegradable surfactant as a surfactant in a plant growth promoting composition using water as a solvent or dispersion medium, it has been found that the adhesion to the surface of plants can be enhanced compared to a plant growth promoting agent containing a petroleum-derived surfactant. A biodegradable surfactant is a surfactant having biodegradability, and preferably can have a cyclic skeleton containing an O atom. By having a cyclic skeleton containing an O atom, it is likely to be a food source for soil microorganisms and is presumed to have high biodegradability. Different from petroleum-derived surfactants that do not have biodegradability, biodegradable surfactants do not cause soil pollution and have a low environmental impact. In addition, biodegradable surfactants generate acids when decomposed, and these acids also have an effect of promoting plant growth. It is considered that the growth of plants is further promoted by a synergistic effect with biostimulants such as zeolites.

[0050] The biodegradable surfactant according to the plant growth promoting composition of the present invention is preferably a biosurfactant, that is, a surfactant produced from the metabolic functions of microorganisms such as bacteria and yeast. Biosurfactants have a high effect of increasing the affinity of a plant growth promoting composition having water as a solvent or dispersion medium to the surface of plants, high biodegradability, low toxicity to organisms, and high dispersibility. In addition, while by-products are generated in the production process of petroleum-derived surfactants, biosurfactants can produce a single substance, so the purity is high. For this reason, the addition amount of biosurfactants can be less than that of petroleum-derived surfactants. And since biosurfactants can increase the affinity of a plant growth promoting composition having water as a solvent or dispersion medium to the surface of plants and enhance the adhesion to the surface of plants, in the plant growth promoting composition of the present invention, including a biosurfactant as a biodegradable surfactant can enhance the adhesion to the surface of plants, so it is preferable in that the effect of promoting plant growth is further enhanced.

[0051] Biosurfactants are classified by chemical structure, and the main types are known to be three types: sugar-type biosurfactants, lipopeptide-type biosurfactants, and fatty acid-type biosurfactants. In the composition for improving plant growth of the present invention, the biodegradable surfactant can be at least one selected from sugar-type biosurfactants, lipopeptide-type biosurfactants, and fatty acid-type biosurfactants. Since any of the chemical structures of sugar-type biosurfactants, lipopeptide-type biosurfactants, and fatty acid-type biosurfactants have multiple functional groups and asymmetric carbon atoms, they are complex and bulky. Moreover, despite having a very complex structure, they have the characteristic that the molecular structure is uniform (high regioselectivity and stereoselectivity). Because biosurfactants are bulky and have a uniform molecular structure, it is presumed that molecules are efficiently oriented at the interface and excellent surface activity is exhibited even at low concentrations. In addition, since any of sugar-type biosurfactants, lipopeptide-type biosurfactants, and fatty acid-type biosurfactants have a cyclic skeleton containing an O atom, they are likely to be a food source for soil microorganisms and are presumed to have high biodegradability.

[0052] In the composition for improving plant growth of the present invention, the sugar-type biosurfactant can be at least one selected from sophorolipid, rhamnolipid, mannosylerythritol lipid, trehalose lipid, cellobiose lipid, and rhamosin.

[0053] The sugar-type biosurfactant is preferably sophorolipid:

[0054]

Chemical formula

[0055] Rhamnolipid:

[0056]

Chemical formula

[0057] Mannosylerythritol lipid:

[0058] [Chemical formula]

[0059] It is at least one selected from the group consisting of these. These are biosurfactants derived from organisms that cannot be synthesized from petroleum. In particular, sophorolipid is more preferable because it has been confirmed to have high biodegradability. Examples of the sophorolipid according to the plant growth promoting composition of the present invention include ACS-Sophor (manufactured by Allied Carbon Solutions). Examples of the rhamnolipid according to the plant growth promoting composition of the present invention include REWOFERM (registered trademark) RL 100 (manufactured by Evonik Industries).

[0060] A typical producer of sophorolipid is the yeast Starmeralla bombicola, and sugars and oils are used as carbon sources. The most well-known producer of rhamnolipid is Pseudomonas aeruginosa. The main producers of mannosylerythritol lipid are basidiomycetous yeasts such as Moesziomyces antarcticus, Moesziomyces aphidis, Pseudozyma tsukubaensis, and Pseudozyma hubeiensis. Plant oils are used as carbon sources.

[0061] In the plant growth promoting composition of the present invention, the lipopeptide-type biosurfactant can be surfactin:

[0062] [Chemical formula]

[0063] Surfactin is a biosurfactant derived from organisms that cannot be synthesized from petroleum. The main producer of surfactin is Bacillus subtilis.

[0064] In the plant growth promoting composition of the present invention, the fatty acid type biosurfactant can be spiculisporic acid:

[0065]

Chemical formula

[0066] Spiculisporic acid is a biosurfactant derived from organisms that cannot be synthesized from petroleum. The main producer of spiculisporic acid is the fungus (mold) Talaromyces speculisporum belonging to the ascomycetes.

[0067] The content of the biodegradable surfactant in the plant growth promoting composition of the present invention (the mass ratio of the biodegradable surfactant to the total amount of the plant growth promoting composition of the present invention) is preferably 0.008 to 0.150% by mass, more preferably 0.010 to 0.100% by mass on an active ingredient basis. When the content of the biodegradable surfactant in the plant growth promoting composition is within the above range on an active ingredient basis, the affinity of the plant growth promoting composition using water as a solvent or dispersion medium for the surface of the plant can be increased, and the adhesion to the surface of the plant can be enhanced. Therefore, the adhesion to the surface of the plant is increased, and the effect of promoting the growth of the plant is enhanced. If the content of the biodegradable surfactant in the plant growth promoting composition is less than the above range, the effect of promoting plant growth is insufficient. Also, if it exceeds the above range, the effect of promoting plant growth will not be improved, and the cost will increase. In addition, when the plant growth promoting composition of the present invention contains one kind of biodegradable surfactant as the biodegradable surfactant, the amount of the active ingredient refers to the content of that one kind, and when it contains two or more kinds of biodegradable surfactants, the amount of the active ingredient refers to the total of those biodegradable surfactants.

[0068] In the plant growth promoting composition of the present invention, the ratio of the content (mass%) of the biodegradable surfactant to the content (mass%) of the biostimulant (biodegradable surfactant / biostimulant) is not particularly limited, but is preferably 0.08 to 1.50, more preferably 0.15 to 1.00.

[0069] The plant growth promoting composition of the present invention contains water as a solvent or dispersion medium. That is, the plant growth promoting composition of the present invention is an aqueous composition in which a biostimulant and a biosurfactant are dissolved or dispersed in water.

[0070] The plant growth promoting composition of the present invention can contain, if necessary, regulators, solvents, emulsifiers, preservatives, antioxidants, fragrances, dyes, pigments, stabilizers, etc.

[0071] The plant growth promoting composition of the present invention may contain alcohol, acetone, acetaldehyde, formic acid, acetic acid, propionic acid, butyric acid, benzenesulfonic acid, etc. as long as the effects of the present invention are not impaired. For example, in the production of the plant growth promoting composition of the present invention, when a compounding agent containing necessary components is added and mixed with water which is a solvent or dispersion medium, alcohol, acetone, acetaldehyde, formic acid, acetic acid, propionic acid, butyric acid, benzenesulfonic acid, etc. contained in the compounding agent may be included as long as the effects of the present invention are not impaired.

[0072] In the production of the plant growth promoting composition of the present invention, the plant growth promoting composition of the present invention can be produced by mixing a biostimulant and a biodegradable surfactant, and further regulators, solvents, emulsifiers, preservatives, antioxidants, fragrances, dyes, pigments, stabilizers, etc. which are used if necessary, with water which is a solvent or dispersion medium. However, these components may be mixed by directly adding them to water (by adding those not dissolved or dispersed in the solvent or dispersion medium as they are), or by adding a compounding agent in which the added components are formulated in a solvent or dispersion medium such as water to water.

[0073] As a method of using the plant growth promoting composition of the present invention, there is a method of directly spraying the plant growth promoting composition of the present invention onto a plant to adhere it to the surface of the leaves, stems, etc. of the plant.

Example

[0074] The plant growth promotion composition of the present invention will be described below with reference to examples. However, the present invention is not limited to the embodiments described below.

[0075] (Verification Experiment 1: Verification Experiment against High Temperature Stress: Hydroponics) <Production of Plant Growth Promotion Composition> The active ingredients of Examples 1 to 5 and Comparative Examples 1 to 4 shown in Table 1 were added to and mixed with water at the blending ratios shown in Table 1 to produce a plant growth promotion composition. As the biostimulant, Zelumbo: Stress Free Z (manufactured by Fuso Chemical Industry Co., Ltd.) (Examples 1 to 5, Comparative Examples 2 to 4) was used. As the biodegradable surfactant, sophorolipid: ACS-Sophor (manufactured by Allied Carbon Solutions) (Examples 1 to 4, Comparative Example 4) or rhamnolipid: REWOFERM (registered trademark) RL 100 (manufactured by Evonik Industries) (Example 5) was used. As the surfactant having no biodegradability, sodium dodecyl sulfate (manufactured by Fujifilm Wako Pure Chemical Corporation) (Comparative Example 3) was used.

[0076] <Verification Experiment by Hydroponics> A verification experiment against high temperature stress was conducted using Komatsuna. The experimental procedure was as follows. Seven days after sowing, Komatsuna that had grown to the extent that true leaves had developed was sandwiched between culture sponges and set on a styrofoam float. A culture solution was placed in a resin container, the float was floated, and bubbling was performed using an air pump and stones. As the liquid fertilizer, a liquid fertilizer based on the Horticultural Experiment Station formula, a general-purpose formulation for hydroponic vegetables developed at the Horticultural Experiment Station of the Ministry of Agriculture, Forestry and Fisheries in the 1960s, was used. Subsequently, the plant growth promotion compositions of Examples 1 to 5 and Comparative Examples 1 to 4 shown in Table 1 were sprayed on the leaves. The plants were cultured in a high temperature environment for 9 days, and the growth state of Komatsuna was observed. The maximum temperature on each day during the 9-day culture period was from 30°C to 43°C. Also, the plants were cultured in a well-lit place. The number of specimens was 40 for each group, and the dry weights were measured in groups of 10. The measured dry weights, their averages, and growth ratios are shown in Table 2.

[0077]

Table 1

[0078] In Table 1, the content of each component is the mass ratio of each component (active ingredient) to the total amount of the plant growth promoting composition.

[0079]

Table 2

[0080] As shown in Table 2, in Examples 1 to 5 in which a biodegradable surfactant (sophorolipid or rhamnolipid) was added to zerumbone as a biostimulant, the growth ratio was larger than that of the non-added ones (Comparative Examples 1 and 2). In addition, in the case of a surfactant (sodium dodecyl sulfate; Comparative Example 3) produced from a petroleum-derived raw material, it was comparable to Comparative Example 2 without the surfactant, and no growth promoting effect by the surfactant was observed. In addition, in Comparative Example 4, since the addition amount of the biodegradable surfactant was small, the effect was small.

[0081] (Verification Experiment 2: Verification Experiment against High Temperature Stress: Soil Cultivation) A verification experiment against high temperature stress was conducted using Akamaru Niju-daikon radish. The experimental procedure is as follows. Using "Soil for Flowers and Vegetables" (manufactured by Santetsu Co., Ltd.) containing some chemical fertilizers as soil, after sowing and planting Akamaru Niju-daikon radish, after the true leaves emerged, a plant growth promoting composition (a plant growth promoting composition containing the active ingredients of Examples 1 to 5 and Comparative Examples 1 to 4 of Verification Experiment 1) was sprayed on the leaf surface. Twenty days after spraying, the grown Niju-daikon radish was harvested. The number of specimens was 14 each, and the weight of each was measured. The total weight average and growth ratio are shown in Table 3.

[0082]

Table 3

[0083] As shown in Table 3, in Examples 1 to 5 in which a biodegradable surfactant (sophorolipid or rhamnolipid) was added to zerumbone as a biostimulant, the growth ratio was larger than that of those without addition (Comparative Examples 1 and 2). Also, in the case of a surfactant (sodium dodecyl sulfate; Comparative Example 3) produced from a petroleum-derived raw material, it was comparable to Comparative Example 2 without the addition of a surfactant, and no growth improvement effect by the surfactant was observed. Also, in Comparative Example 4, since the addition amount of the biodegradable surfactant was small, the effect was small.

Claims

1. A biostimulant for alleviating abiotic stress in plants or promoting plant growth, a biodegradable surfactant, and water, wherein the content of the biodegradable surfactant is 0.008 to 0.150% by mass based on the active ingredient, characterized by a plant growth improvement composition.

2. The biostimulant is at least one selected from the group consisting of zeatin, zeatin analogs, zeatin derivatives, zeatin salts, zeatin analog salts, zeatin derivative salts, salicylic acid, polyamines, geldanamycin, trimethylglycine, perillaldehyde, citral, carotene, lycopene, zeaxanthin, cryptoxanthin, lutein, phenylethyl isothiocyanate, ursolic acid, choline, alginic acid, fulvic acid, humic acid, 5-aminolevulinic acid, oxidized glutathione, trehalose, and 2-hexanal. The plant growth improvement composition according to Claim 1.

3. The biodegradable surfactant is a biosurfactant. The plant growth improvement composition according to Claim 1 or 2.

4. The biodegradable surfactant is at least one selected from the group consisting of sugar-based biosurfactants, lipopeptide-based biosurfactants, and fatty acid-based biosurfactants. The plant growth improvement composition according to Claim 1 or 2.

5. The biodegradable surfactant is at least one selected from the group consisting of sophorolipid, mannosylerythritol lipid, rhamnolipid, trehalose lipid, cellobiose lipid, reamocin, surfactin, and spiculisporic acid. The plant growth improvement composition according to Claim 1 or 2.

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