Growth stimulant for grasses

Abstract

To provide growth promoters for gramineous plants.SOLUTION: A growth promoter for gramineous plants contains at least one compound selected from oxo fatty acid or derivatives thereof or salts thereof.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a growth promoter for grasses. [Background technology]

[0002] Rice is one of the world's most important food crops for humans. Therefore, high productivity is desirable. However, rice is susceptible to heat stress, and extremely high temperatures can lead to low rice yields. For this reason, research is being conducted to promote rice growth under high-temperature conditions.

[0003] Patent Document 1 discloses a technique for improving the resistance of rice to high temperature stress by treating rice with a 6-anilinoprine derivative.

[0004] Furthermore, Patent Document 2 discloses a method for efficiently producing ketooctadecadienoic acid, a functional ingredient known to exhibit fat-burning effects, using enzymes. It also states that the obtained ketooctadecadienoic acid can be used because it exhibits a strong resistance-inducing effect.

[0005] Furthermore, Patent Document 3 describes a plant activator characterized by containing an oxo fatty acid derivative or its salt or ester as an active ingredient, which has low soil contamination and toxicity and excellent resistance-inducing effect. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-31654 [Patent Document 2] Japanese Patent Publication No. 2020-25534 [Patent Document 3] International Publication No. 2018 / 168860 [Overview of the project] Problem to be Solved by the Invention

[0007] However, since the agent disclosed in Patent Document 1 is a complex compound, the synthesis cost thereof is high. In addition, since it is not a naturally occurring substance, it may cause soil pollution if it remains in soil, so that it cannot be applied through soil irrigation, and there are restrictions on the method of use.

[0008] Further, Patent Documents 2 and 3 disclose plant activators that induce resistance, but no findings have been reported on promoting rice growth under high-temperature stress.

[0009] The present invention has been made in view of the above problems, and an object thereof is to provide a growth promoter that can safely, stably and effectively promote the growth of gramineous plants by appropriately spraying or irrigating plants, particularly a growth promoter that can promote growth during cultivation under high temperature. Means for Solving the Problem

[0010] The present invention relates to a growth promoter for gramineous plants, which contains at least one compound selected from oxo fatty acids, derivatives or salts thereof.

[0011] The oxo fatty acid is represented by the following formula (I): HOOC-(R 1 )-CH=CH-C(=O)-R 2 (I) [In formula (I), R 1 represents a linear or branched, saturated or unsaturated hydrocarbon group containing 6 to 12 carbon atoms. R 2 represents an alkyl group having 2 to 8 carbon atoms, which may contain one or more branches and / or double bonds.], or the following formula (II): HOOC-(R 3 )-C(=O)-CH=CH-R 4 (II) [In formula (II), R3 represents a linear or branched, saturated or unsaturated hydrocarbon group containing 3 to 10 carbon atoms. R 4 represents a hydrocarbon group having 4 to 11 carbon atoms, which may optionally contain one or more branches and / or double bonds.] is preferably an oxo fatty acid represented by

[0012] In the above formula (I), R 1 contains a double bond that forms a conjugated double bond with the double bond between the α-carbon and β-carbon of the carbonyl group in the above formula (I), and in the above formula (II), R 4 preferably contains a double bond that forms a conjugated double bond with the double bond between the α-carbon and β-carbon of the carbonyl group in the above formula (II).

[0013] It is preferable that the oxo fatty acid represented by the above formula (I) and the oxo fatty acid represented by the above formula (II) are ketooctadecadienoic acids.

[0014] In the above formula (I), R 1 is a linear or branched hydrocarbon group having 9 carbon atoms, and R 2 is an alkyl group having 5 carbon atoms, and in the above formula (II), R 3 is a linear or branched hydrocarbon group having 7 carbon atoms, and R 4 preferably has 7 carbon atoms and has the structure CH3-CH2-CH2-CH2-CH2-CH=CH-.

[0015] The oxo fatty acid is preferably at least one selected from the group consisting of 9-oxo-10,12-octadecadienoic acid, 13-oxo-9,11-octadecadienoic acid, 5-oxo-6,8-octadecadienoic acid, 6-oxo-9,12-octadecadienoic acid, 8-oxo-9,12-octadecadienoic acid, 10-oxo-8,12-octadecadienoic acid, 11-oxo-9,12-octadecadienoic acid, 12-oxo-9,13-octadecadienoic acid and 14-oxo-9,12-octadecadienoic acid.

[0016] The aforementioned growth promoter for grasses preferably contains at least two types of oxo fatty acids.

[0017] The growth promoter for the grass species preferably comprises at least one oxo fatty acid represented by formula (I) and at least one oxo fatty acid represented by formula (II).

[0018] In the aforementioned growth promoter for grasses, it is preferable that the oxo fatty acid represented by formula (I) is 13-oxo-9,11-octadecadienoic acid, and the oxo fatty acid represented by formula (II) is 9-oxo-10,12-octadecadienoic acid.

[0019] The growth promoter for grasses is preferably such that the ratio of the content of 9-oxo-10,12-octadecadienoic acid to the content of 13-oxo-9,11-octadecadienoic acid is 0.3 to 2.0 by weight.

[0020] Preferably, the growth promoter is a growth promoter for grasses used when cultivating grasses under conditions of an average temperature of 30°C or higher.

[0021] Preferably, the growth promoter for grasses is a growth promoter for grasses used as a spray or dipping agent applied to the stems, leaves, or roots of the plant, or as a soil drenching agent.

[0022] The aforementioned growth promoter for grasses preferably further comprises a hydroxylated fatty acid or a derivative thereof or a salt thereof.

[0023] It is preferable that the hydroxylated fatty acid is at least one selected from the group consisting of 9,10,13-trihydroxy-11-octadecaenoic acid and 9,12,13-trihydroxy-10-octadecaenoic acid.

[0024] Note that "octadecaenoic acid" is a commonly used notation (for example, in Japanese Patent Publication No. 3-14539, etc.), and the above-mentioned "9,10,13-trihydroxy-11-octadecaenoic acid" can also be written as "9,10,13-trihydroxyoctadeca-11-enoic acid" or "9,10,13-trihydroxy-11-octadecenoic acid". The structural formula of "9,10,13-trihydroxy-11-octadecaenoic acid" is shown in structural formula (1) below.

[0025] [ka]

[0026] Similarly, the aforementioned "9,12,13-trihydroxy-10-octadecaenoic acid" can also be written as "9,12,13-trihydroxyoctadeca-10-enoic acid" or "9,12,13-trihydroxy-10-octadecenoic acid". The structural formula of "9,12,13-trihydroxy-10-octadecaenoic acid" is shown in structural formula (2) below.

[0027] [ka] [Effects of the Invention]

[0028] The growth promoter for grasses of the present invention can promote the healthy growth of grasses. Furthermore, even when cultivated grasses have been or will be exposed to high-temperature stress, treating them with the growth promoter of the present invention can significantly promote their growth without causing high-temperature damage. [Brief explanation of the drawing]

[0029] [Figure 1] This figure shows the growth status of each test crop before application of a growth stimulant solution under high-temperature conditions. [Figure 2] This figure shows the growth status of each test crop cultivated under high-temperature conditions after application of a growth stimulant solution. [Figure 3] This figure shows the growth status of each test crop before application of the growth stimulant solution under normal temperature conditions. [Figure 4] This figure shows the growth status of each test crop cultivated under normal temperature conditions after application of a growth stimulant solution. [Figure 5] This figure shows the results of a growth survey under high-temperature conditions. [Figure 6] This figure shows the results of a growth survey under high-temperature conditions. [Figure 7] This figure shows the results of a growth survey under normal temperature conditions. [Figure 8] This figure shows the results of a growth survey under normal temperature conditions. [Modes for carrying out the invention]

[0030] The present invention relates to a growth promoter for grasses, characterized by comprising at least one compound selected from oxo fatty acids or their derivatives or salts.

[0031] In this invention, the term "grasses" refers to plants belonging to the family of monocots, angiosperms, which comprises approximately 700 genera and 8,000 species, and more specifically to Asian rice, and among Asian rice, to the Japonica species, which has low heat tolerance. The growth promoter for grasses of this invention is suitably applied to such grasses, particularly Asian rice, such as the Japonica species.

[0032] As shown in the examples below, applying the growth promoter of the present invention to grasses can promote the growth of the grasses, and in particular, the growth of grasses is promoted even when cultivated under high-temperature conditions.

[0033] Therefore, in plants to which the growth promoter of the present invention is applied, high-temperature damage to plant growth is not observed even when exposed to high-temperature stress. Consequently, it is possible to achieve excellent yield increase and improved harvesting efficiency even when cultivated under high-temperature conditions.

[0034] In this specification, "promoting plant growth" (hereinafter sometimes referred to as "growth promotion") means an increase in leaf area, an increase in plant height, an increase in plant weight, an increase in the number or weight of seeds, an increase in the number or weight of fruits, an increase in the diameter or length of the root cross-section, an increase in the number of roots, and especially an increase in the number of fine roots.

[0035] The growth promoter for grasses of the present invention comprises, as an active ingredient, at least one compound selected from oxo fatty acids or their derivatives or salts.

[0036] More specifically, the growth promoter for grasses of the present invention is The following equation (I): HOOC-(R 1 )-CH=CH-C(=O)-R 2 (I) [In formula (I), R 1 R represents a linear or branched, saturated or unsaturated hydrocarbon group containing 6 to 12 carbon atoms. 2 This represents a C2-C8 alkyl group that may contain one or more branches and / or double bonds. Alternatively, the following formula (II): HOOC-(R 3 )-C(=O)-CH=CH-R 4 (II) [In formula (II), R 3 R represents a linear or branched, saturated or unsaturated hydrocarbon group containing 3 to 10 carbon atoms. 4 This represents a hydrocarbon group having 4 to 11 carbon atoms, which may contain one or more branches and / or double bonds. It is characterized by containing at least one compound selected from oxo fatty acids represented by or their derivatives or salts thereof.

[0037] Furthermore, oxo fatty acids and compounds represented by formula (I) or (II) above include all geometric isomers and stereoisomers having the same structural formula. As used herein, the term “stereoisomer” may refer to any of the various stereoisomer configurations that may exist in the compounds of this disclosure. For example, the compounds represented by formula (I) or (II) of this disclosure contain a double bond, where the substituent may be in an E or Z configuration.

[0038] Preferably, in the oxo fatty acids contained in the growth promoter for grasses of the present invention, for example, R of formula (I) above 1 R in formula (II) may include a double bond that forms a conjugated double bond with the double bond between the α and β carbons of the carbonyl group in formula (I). 4 This may include a double bond that forms a conjugated double bond with the double bond between the α and β carbons of the carbonyl group in formula (II).

[0039] For example, ketooctadecadienoic acid is a suitable oxo fatty acid. More preferably, in the above formula (I), R 1 R can be a straight-chain or branched hydrocarbon group having 9 carbon atoms, and 2 R can be an alkyl group having 5 carbon atoms. Also, in the above formula (II), R 3 R can be a straight-chain or branched hydrocarbon group having 7 carbon atoms, and 4 In the case of having 7 carbon atoms, it is preferable to have the structure CH3-CH2-CH2-CH2-CH2-CH=CH-.

[0040] For example, specific examples of ketooctadecadienoic acid include 9-oxo-10,12-octadecadienoic acid (9-oxoODA), 13-oxo-9,11-octadecadienoic acid (13-oxoODA), 5-oxo-6,8-octadecadienoic acid, 6-oxo-9,12-octadecadienoic acid, 8-oxo-9,12-octadecadienoic acid, 10-oxo-8,12-octadecadienoic acid, 11-oxo-9,12-octadecadienoic acid, 12-oxo-9,13-octadecadienoic acid, and 14-oxo-9,12-octadecadienoic acid. In this specification, "active ingredient" means oxo fatty acids, including the specific examples listed. Oxo fatty acids have properties that activate plant growth. By bringing the growth promoter for grasses of the present invention, which contains oxo fatty acids or their derivatives or salts as active ingredients, into contact with a part of the stem, leaves, or roots of a plant, plant growth can be promoted, resulting in higher yields and better crop quality. Preferably, the growth promoter for grasses of the present invention contains at least two types of oxo fatty acids or their derivatives or salts as one of its active ingredients.

[0041] As the derivative of the oxo fatty acid, an ester is preferable. The esters of the oxo fatty acid of the present invention are not limited to these, but examples include methyl esters, ethyl esters, propyl esters, butyl esters, pentyl esters, isopentyl esters, octyl esters, and the like.

[0042] The salts of oxo fatty acids are not particularly limited as long as they are one or more agriculturally acceptable salts, such as alkali metal salts like sodium salts and potassium salts, or ammonium salts like alkylammonium salts such as ammonium salts and tetramethylammonium salts.

[0043] The growth promoter for grasses of the present invention may contain at least two oxo fatty acids as active ingredients. By combining two or more oxo fatty acids, the growth promoter for grasses of the present invention may exhibit an even higher growth-promoting effect. For example, the two oxo fatty acids may be a combination of at least one oxo fatty acid represented by formula (I) and at least one oxo fatty acid represented by formula (II). Preferably, the two oxo fatty acids may be a combination of 9-oxo-10,12-octadecadienoic acid (9-oxoODA) and 13-oxo-9,11-octadecadienoic acid (13-oxoODA).

[0044] In one embodiment of the present invention, the growth promoter for grasses of the present invention comprises 13-oxo-9,11-octadecadienoic acid or its salt or derivative and 9-oxo-10,12-octadecadienoic acid or its salt or derivative as oxo fatty acids. For example, the content of 13-oxo-9,11-octadecadienoic acid or its salt or derivative is 1.0 to 10.0 by weight relative to the content of 9-oxo-10,12-octadecadienoic acid or its salt or derivative, preferably 2.0 to 5.0.

[0045] The growth promoter for grasses of the present invention may contain, in addition to at least one compound selected from oxo fatty acids or their derivatives or salts, hormone precursors such as terpenes, amino acids, nucleic acids, phospholipids, and the like.

[0046] The growth promoter for grasses of the present invention can provide excellent growth promotion to grasses treated with the growth promoter for grasses of the present invention, even if the grasses treated with the growth promoter for grasses of the present invention have been or will be exposed to high-temperature stress. For example, the growth promoter for grasses of the present invention is preferably used when cultivating grasses under conditions where the average temperature is 30°C or higher, or when there is a possibility that grasses will be cultivated under conditions where the average temperature is 30°C or higher. Under such conditions, grasses are susceptible to high-temperature damage, and their growth is suppressed, resulting in problems such as a lack of increase in height and weight. The present invention is particularly beneficial because it promotes the growth of grasses even under such high-temperature conditions. High yields can be obtained in grasses to which the product has been applied. In this specification, "average temperature" is defined as the average value of the maximum daily temperature during the panicle formation stage of grasses.

[0047] In one embodiment of the present invention, at least one compound selected from oxo fatty acids or their derivatives or salts may be used at a concentration of 10 mg / L or less. The preferred concentration of at least one compound selected from oxo fatty acids or their derivatives or salts depends on the cultivation conditions and growth stage of the grass plants to which it is applied, the timing and method of application of the growth stimulant for grass plants, etc., and can be appropriately set to suit the application rate, however, if the concentration exceeds 10 mg / L, there is a risk of phytotoxicity to the plants. The lower limit of the concentration of at least one compound selected from oxo fatty acids or their derivatives or salts is not particularly limited, but 0.05 mg / L or more is preferred. In one preferred embodiment of the present invention, the concentration of at least one compound selected from oxo fatty acids or their derivatives or salts is 0.05 to 10 mg / L.

[0048] The growth promoter for grasses of the present invention may optionally contain a compatible surfactant and / or diluent or carrier suitable for use as a growth promoter for grasses. For example, a diluent may improve the dispersibility in a solvent of at least one compound selected from oxo fatty acids or their derivatives or salts. In addition, surfactants such as dispersing aids and wetting agents may be included to improve the solubility and dispersibility of the oxo fatty acid derivatives used in the present invention in diluents. These additive components are not particularly limited as long as they are agriculturally acceptable. Furthermore, the growth promoter for grasses of the present invention may also contain, in addition to surfactants, diluents, and carriers, other components commonly used in pesticide formulations, such as pH adjusters, spreading agents to enhance adhesion to grasses or soil, binders, antioxidants, and other components beneficial to plants, such as one or more fertilizer components.

[0049] The growth promoter for grasses of the present invention may contain at least one compound selected from oxo fatty acids or their derivatives or salts, and their origins are not particularly limited. The oxo fatty acid or its derivative or salt, such as ketooctadecadienoic acid of the present invention, may be obtained, for example, by chemical synthesis, or it may be produced, for example, using microorganisms, or obtained by reacting enzymes derived from microorganisms with a substrate such as a fatty acid. The growth promoter for grasses of the present invention may contain at least one compound selected from oxo fatty acids or their derivatives or salts at a desired concentration, and for example, if an oxo fatty acid produced using microorganisms is used as the oxo fatty acid derivative, a mixture containing the oxo fatty acid may be used as the growth promoter for grasses. If a biosurfactant secreted by microorganisms is included in the mixture, it may be possible to improve the dispersibility of the growth promoter for grasses of the present invention without including the additive components described above. When the oxo fatty acid or its derivative itself is insoluble, it may be possible to emulsify it with a biosurfactant and disperse it in water.

[0050] In one embodiment of the present invention, the growth promoter for grasses of the present invention may further contain, in addition to at least one compound selected from oxo fatty acids or their derivatives or salts as an active ingredient, a hydroxylated fatty acid or its derivative or salt. A growth promoter for grasses with an even higher activating effect may be obtained.

[0051] Hydroxylated fatty acids or their derivatives or salts thereof having the structural formulas shown in the following formulas (III) and / or (IV) can be preferably used. HOOC-(R 5 )-CH(OH)-CH(OH)-CH=CH-CH(OH)-R 6 (III), and / or HOOC-(R 5)-CH(OH)-CH=CH-CH(OH)-CH(OH)-R 6 (IV) (In equations (III) and / or (IV), R 5 R is a linear or branched hydrocarbon group having 4 to 12 carbon atoms, which may contain one or more double bonds and / or OH groups, and if it contains double bonds, the position of the double bonds is not limited. 6 (A is a linear or branched hydrocarbon group having 2 to 8 carbon atoms, which may contain one or more double bonds and / or OH groups, and if a double bond is present, the position of the double bond is not limited).

[0052] Furthermore, as derivatives of hydroxylated fatty acids or salts thereof, those exemplified above as derivatives or salts of oxo fatty acids can be suitably used. In addition, the hydroxylated fatty acids of this disclosure include all geometric and stereoisomers of the compound represented by formula (III) and / or (IV).

[0053] In one embodiment of the present invention, R in formula (III) and / or (IV) 5 The hydrocarbon group has 6 to 8 carbon atoms, R 6 The hydrocarbon group has 4 to 6 carbon atoms. In another embodiment, the R in the above hydroxylated fatty acid 5 is, -(CH2) n -(n is an integer between 4 and 12) is the structure, R 6 C n H 2n+1 -(n is an integer between 2 and 8) structure. Furthermore, in another embodiment, R in the above hydroxylated fatty acid 5 This is an alkylene group (-(CH2)7-) with 7 carbon atoms, and R 6 It is preferable that the element is a C5 alkyl group (CH3CH2CH2CH2CH2-).

[0054] Preferably, the hydroxylated fatty acid of the present disclosure may be, but is not limited to, at least one selected from the group consisting of 9,10,13-trihydroxy-11-octadecaenoic acid and 9,12,13-trihydroxy-10-octadecaenoic acid.

[0055] As described above, the growth promoter for grasses of the present invention, comprising at least one compound selected from oxo fatty acids or their derivatives or salts, is characterized by exhibiting a remarkably excellent plant activating effect, which, when applied to grasses, brings about excellent growth promotion in the grasses, and as a result promotes the growth of the grass seeds and increases the yield of the seeds.

[0056] The growth promoter for grasses of the present invention can increase the content of sugars and amino acids in the leaves of grasses to which it is applied, which are thought to correlate with the yield of seeds. In other words, the growth promoter for grasses of the present invention can promote the growth of plant seeds and increase the seed weight and number of seeds per plant. Therefore, the growth promoter for grasses of the present invention is a yield increaser. Note that "increased seed yield" means that the amount of seeds harvested increases, for example, that the seed weight and / or number of seeds per plant are greater than in a group of plants not treated with the growth promoter for grasses of the present invention.

[0057] The growth promoter for grasses of the present invention can also increase the content of plant hormones in the leaves of the grasses to which it is applied, which is associated with increased seed yield. The growth promoter for grasses of the present invention can increase the content of plant hormones that have physiological effects, for example, promoting flower bud formation and ovary growth.

[0058] Therefore, the growth promoter for grasses of the present invention can be suitably used to increase the yield of grass grains. Increased grain yield can be achieved in grasses to which the growth promoter for grasses of the present invention can be applied. The grasses to which the growth promoter for grasses of the present invention can be applied are not limited to rice, but can be suitably applied to, for example, wheat, barley, rye, oats, hulless barley and other grains, rice, sorghum, maize, foxtail millet, proso millet, barnyard millet, finger millet, pearl millet, and turfgrass.

[0059] Furthermore, the types of rice to which the grass growth promoter of the present invention can be applied are not limited to the Asian rice and Asian rice japonica varieties mentioned above, but can be appropriately selected depending on the purpose. Examples of rice varieties that can be exemplified include sake rice such as Hakutsuru Nishiki, Yamada Nishiki, Gohyakumangoku, Miyama Nishiki, Omachi, Hattan, Hattan Nishiki, Ginpu, Yumesansa, Wakamizu, and Yumenoka, and edible rice such as Nihonbare, Koshihikari, Hitomebore, Hinohikari, Akitakomachi, Kinuhikari, Nanatsuboshi, and Haenuki.

[0060] The growth promoter for grasses of the present invention can be applied to grasses by any method. The application method is not particularly limited as long as it involves contact with the plant body, such as the roots, stems, and leaves. The growth promoter for grasses of the present invention may be applied in direct contact with the grass plant body, or it may be applied to the cultivation carrier, such as soil or growing medium, on which the grass plant body is established. For example, the growth promoter for grasses of the present invention can be used as a spray or dipping agent applied to the stems, leaves, or roots of the plant, or as a soil drenching agent. Specific application methods can be appropriately selected depending on the cultivation method of the grass plant to be treated, but examples include ground liquid application, ground solid application, aerial liquid application, aerial solid application, surface application, application in a facility, soil mixing application, soil drenching application, surface treatment such as coating, seedling tray application, single flower treatment, and base treatment. Furthermore, the growth promoter for grasses of the present invention may be mixed with fertilizer components for grasses and used as a plant fertilizer. The growth promoter for grasses of the present invention may also be encapsulated in porous structures or capsules, or impregnated into sheets, and used as a sustained-release agent. The form of the growth promoter for grasses of the present invention is not particularly limited. The growth promoter for grasses of the present invention may be in liquid or gel form, or in solid form (block, powder, granules, etc.). In the case of a liquid composition, it can be used as is or as a concentrated type after dilution. The growth promoter for grasses of the present invention imparts a plant growth promoting effect to plants during grass cultivation, resulting in increased grain yield due to increased plant body size, such as increased crop weight, and improved grain yield and harvesting efficiency due to its flower bud formation promoting effect.

[0061] The growth promoter for grasses of the present invention can provide a growth-promoting effect to grasses through simple treatments such as spraying, eliminating the need for special equipment, which is a significant advantage of the present invention. Furthermore, since oxo fatty acids and the like are oxides of naturally occurring fatty acids, the growth promoter for grasses of the present invention has a low environmental impact and causes virtually no phytotoxicity to the grasses to which it is applied, making it superior in these respects as well.

[0062] The application of the growth promoter for grasses of the present invention to grasses and / or cultivation carriers can be carried out, for example, by applying to the grasses and / or cultivation carriers in the form of a liquid in which at least one compound selected from oxo fatty acids or their derivatives or salts is dissolved or dispersed in water and / or a water-soluble solvent. For example, a liquid in which at least one compound selected from oxo fatty acids or their derivatives or salts is dissolved or dispersed can be sprayed or applied to the above-ground parts (stem, leaves, etc.) of the target plant.

[0063] The growth promoter for grasses of the present invention can be applied to target plants at various stages of their growth. For example, application may occur during the germination period (around emergence after sowing), seedling rearing, seedling transplanting, vegetative growth, tillering, panicle formation, panicle development, before flowering, just before heading, or during the heading stage. Application only needs to be done at least once, for example, at seedling transplanting. It may also be applied in multiple stages. The growth promoter for grasses of the present invention can significantly promote the growth of plants under high-temperature conditions, and is therefore suitably applied when the average temperature is 30°C or higher, or when the average temperature is expected to reach 30°C or higher. [Examples]

[0064] The present invention will be described based on examples, but the present invention is not limited to these examples.

[0065] [Example 1] • Preparation of growth-promoting solution As a raw material containing fatty acids, 580g of 90% pure linoleic acid (manufactured by NOF Corporation) was used. To this, 216g of potassium carbonate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 280g of dipotassium hydrogen phosphate (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 13,000mL of distilled water were added to prepare the test solution. The pH of the test solution at this time was 9.0.

[0066] 40 mg of lipoxygenase (Nacalai Tesque Co., Ltd., derived from soybeans) was added to the test solution, and the reaction was carried out at 15°C for 3 hours while aerating with oxygen and stirring. The reaction mixture was then placed in a 90°C water bath for 90 minutes. The resulting reaction solution was designated as Solution A.

[0067] 6500 mL of solution A was mixed with 35 mL of phosphoric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to adjust the pH to 7.0. This solution was reacted at 50°C for 22 hours with oxygen aeration and stirring, and then the reaction mixture was placed in a 90°C water bath for 2 hours. The resulting reaction solution was designated as solution B.

[0068] The entire contents of solution A and the entire contents of solution B obtained above were mixed together, and the resulting mixture was used as a standard substance along with 13-oxoODA (13-oxo-9,11-octadecadienoic acid), 9-oxoODA (9-oxo-10,12-octadecadienoic acid), and 9,10,13-trihydroxy-11-octadecenoic acid (9,10,13-trihydroxy-11-octadecenoic acid), manufactured by Cayman Chemicals, and 9,10,13-trihydroxy-11-octadecenoic acid, manufactured by La Rhodan Fine Chemicals. Using 9,12,13-trihydroxy-10-octadecenoic acid, MS 2Quantitative analysis was performed using LC-MS with spectral analysis. Additionally, ketooctadecadienoic acid (13-oxoODA, 9-oxoODA) was quantified using the absolute calibration curve method at a detection wavelength of UV 272 nm, and trihydroxyoctadecadienoic acid was quantified using the detection wavelength of UV 210 nm.

[0069] The combined yield of isomers such as (E,E) and (E,Z) was 3.7% for 13-oxoODA. The yield of 9-oxoODA was 1.7%. The combined yield of 9,10,13-trihydroxy-11-octadecaenoic acid and 9,12,13-trihydroxy-10-octadecaenoic acid was 1.2% (peaks could not be separated by LC-MS), and the recovery rate of linoleic acid was 84.1%.

[0070] The yield (%) was calculated based on the following formula. Yield (%) = (wt%) of 13-oxoODA, 9-oxoODA, 9,10,13-trihydroxy-11-octadecaenoic acid or 9,12,13-trihydroxy-10-octadecaenoic acid produced / (initial wt%) of linoleic acid used as the starting material

[0071] 0.8 mL of the mixture of solutions A and B obtained above was diluted in 2000 mL of deionized water to be used as the standard solution for the growth stimulant, and 4.0 mL of the mixture of solutions A and B was diluted in 2000 mL of deionized water to be used as the 5x volume solution of the growth stimulant (meaning 5 times the concentration of the standard solution). The concentrations of 13-oxoODA in the standard solution and the 5x volume solution were 0.4 ppm (≒0.37 ppm) and 2 ppm (≒1.9 ppm), respectively. Furthermore, the standard solution and the 5x volume solution were each diluted 1000 times using deionized water to obtain the standard solution and the 5x volume solution of the growth stimulant for spraying.

[0072] • Rice growth promoting effect Rice seeds (variety: Nipponbare) (5g per plot) were soaked in water and allowed to absorb water for 3 days in an artificial climate chamber at 20°C. After that, they were left overnight at 32°C to induce germination in a pigeon-chest shape. 300mL of autoclaved growing medium (vegetable and flower seed-starting medium (manufactured by Takii Seed Co., Ltd.); fertilizer components: N: 270mg / L, P2O5: 200mg / L, K2O: 280mg / L; pH 7.0) was packed into pots (10cm in diameter, 5cm in height, 0.4L in volume), sterilized in 120°C for 20 minutes, mixed with 200mL of water, and germinated seeds (8g per plot) were sown. After sowing, the plants were cultivated in an artificial climate chamber (LH-60FL3-DT: manufactured by Nippon Ika Kikai Seisakusho Co., Ltd.) with sunlight set to 14 hours of light / 10 hours of darkness and temperature set to 28°C / 23°C.

[0073] After cultivation for 7 days following sowing until panicle formation, the standard spray solution and a 5x diluted solution, both diluted 1000 times, were sprayed onto the leaves using a spray bottle. The application amount per pot was 10 μL (standard amount) equivalent to the standard solution before dilution, and 10 μL (5x diluted) equivalent to the 5x diluted solution before dilution. As a control, deionized water was sprayed onto the leaves instead of the growth stimulant solution (standard solution and 5x diluted solution) and served as the no-application group.

[0074] After application, each test crop was cultivated in an artificial climate chamber under normal temperature conditions (sunlight: 14 hours light / 10 hours dark, air temperature: 28°C / 21°C) or high-temperature conditions (sunlight: 14 hours light / 10 hours dark, air temperature: 35°C / 25°C). The untreated group was cultivated in the same manner, except that the growth stimulant solution was not applied.

[0075] After cultivation for 7 days following application, the growth of the test crops in each plot was investigated. No top dressing or pesticide application was carried out. The growth status of each test crop before application and after cultivation for 7 days following application is shown in Figures 1 to 4. Figure 1 shows the growth status of each test crop before application of the growth stimulant solution under high temperature conditions. Figure 2 shows the growth status of each test crop after cultivation for 7 days under high temperature conditions following application of the growth stimulant solution. Figure 3 shows the growth status of each test crop before application of the growth stimulant solution under normal temperature conditions. Figure 4 shows the growth status of each test crop after cultivation for 7 days under normal temperature conditions following application of the growth stimulant solution.

[0076] The growth survey of the test crops was conducted by measuring the plant height and above-ground wet weight of 10 plants randomly selected from each plot. Plant height was measured from the base of the stem to the tips of the branches and leaves for each test crop. Above-ground wet weight was determined by cutting the above-ground portion of each test crop and measuring its weight to find the fresh weight of the plant. The results of each growth survey are shown in Table 1 (under high temperature conditions) and Table 2 (under normal temperature conditions), and in Figures 5 and 6 (under high temperature conditions) and Figures 7 and 8 (under normal temperature conditions), respectively.

[0077] [Table 1]

[0078] [Table 2]

[0079] In the test samples cultivated under high-temperature conditions of 35°C after application of the growth promoter in this embodiment, both the standard dose and the 5x dose dose groups showed a significant increase in plant height and above-ground wet weight compared to the untreated group, as shown in Table 1 and Figures 5 and 6. A comparison of Figures 1 and 2 also shows that the growth of the test plants in both the standard dose and 5x dose dose groups was significantly promoted under high-temperature conditions of 35°C. On the other hand, in the test samples cultivated under normal temperature conditions of 28°C after application of the test samples, both the standard dose and 5x dose dose groups showed a significant increase in above-ground wet weight compared to the untreated group, as shown in Table 2 and Figures 7 and 8. As shown in Figures 3 and 4, under normal temperature conditions of 28°C, plant height increased in both the standard dose and 5x dose dose groups compared to the untreated group, but the difference was not statistically significant.

[0080] From the above results, it can be seen that the growth promoter of this embodiment has the effect of an activator that promotes the growth of grasses. Furthermore, it can be seen that the growth promoter of this embodiment is particularly effective in promoting the growth of grasses that have been exposed to or will be exposed to high temperature stress.

Claims

1. It contains oxo fatty acids or their salts, and hydroxylated fatty acids or their salts. The oxo fatty acid or its salt is 13-oxo-9,11-octadecadienoic acid or its salt, and 9-oxo-10,12-octadecadienoic acid or its salt. The hydroxylated fatty acid is at least one selected from the group consisting of 9,10,13-trihydroxy-11-octadecaenoic acid and 9,12,13-trihydroxy-10-octadecaenoic acid. A growth stimulant for grasses, characterized in that it is used when cultivating grasses under conditions where the average daily maximum temperature during the panicle formation stage of grasses is 30°C or higher.

2. A growth promoter for grasses according to claim 1, wherein the ratio of the content of 9-oxo-10,12-octadecadienoic acid to the content of 13-oxo-9,11-octadecadienoic acid is 0.3 to 2.0 by weight.

3. A growth promoter for grasses according to claim 1, which is a spray or immersion agent applied to the stems, leaves, or roots of a plant, or an agent applied to the soil.

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