Plant growth promoter, plant cultivation composition, and plant growth promotion method

Abstract

A plant growth promoter 1a contains a lipid 11. The lipid 11 is at least one selected from the group consisting of acylglycerols that contain a C10-20 fatty acid residue and a sugar residue, and C10-20 fatty acids.

Description

Plant growth promoter, plant cultivation composition, and plant growth promotion method

[0001] The present disclosure relates to a plant growth promoter, a composition for cultivating plants, and a method for promoting plant growth.

[0002] BACKGROUND ART It is known that naturally occurring substances are used to improve crop yields.

[0003] For example, U.S. Patent No. 5,929,999 describes a rich culture of a given microbial strain, in which an effective amount of the microbial strain or culture is applied to the plant or its surroundings to enhance plant growth.

[0004] Patent Document 2 describes a microbial plant growth promoting composition produced by a predetermined method.

[0005] Non-patent document 1 describes the probiotic activity of Rhizobium laguerreae on the growth and quality of spinach.

[0006] Patent Document 3 describes an agent for improving iron availability in plants. This agent for improving iron availability in plants contains glutamic acid, arginine, or both of these amino acids at a predetermined concentration, and increases the expression level of a series of genes involved in iron availability in plants.

[0007] US Patent No. 5,999,649 describes a method for promoting crop production, which method comprises administering to crop plants a composition containing a natural compound such as adenosine.

[0008] Patent Document 5 describes an agricultural and horticultural fertilizer containing an extract of photosynthetic prokaryotic microorganisms such as cyanobacteria.

[0009] Conventionally, a technique utilizing monogalactosyldiacylglycerol, a glycolipid biosynthesized by plants and photosynthetic microorganisms and abundantly contained in their biomembranes, has been known.

[0010] For example, Patent Document 6 describes a plant pest feeding inhibitor containing monogalactosyldiacylglycerol as an active ingredient and a method for inhibiting pest feeding on plants by artificially applying monogalactosyldiacylglycerol to the plants.

[0011] Patent Document 7 describes extracts rich in polar lipids obtained from photosynthetic organs and tissues of macroalgae, microalgae, photosynthetic bacteria, and plants. The extracts contain, for example, monogalactosyldiacylglycerol as a polar lipid. The extracts are used, for example, as emulsifiers.

[0012] Japanese Patent Application Laid-Open No. 2018-11600 Japanese Patent Application Laid-Open No. 63-501286 Japanese Patent Application Laid-Open No. 2014-73993 Japanese Patent Application Laid-Open No. 2013-515784 Japanese Patent Application Laid-Open No. 11-335191 Japanese Patent Application Laid-Open No. 2007-112759 Japanese Patent Application Laid-Open No. 2023-546567

[0013] Jimenez-Gomez et al., “Probiotic activities of Rhizobium laguerreae on growth and quality of spinach”, Scientific Reports, 2018, Vol. 8, 295

[0014] The techniques described in the above patent and non-patent documents need to be reconsidered from the viewpoint of promoting plant growth. Therefore, the present disclosure provides a novel technique that is advantageous from this viewpoint.

[0015] The present disclosure provides a plant growth promoter comprising at least one lipid selected from the group consisting of an acylglycerol containing a fatty acid residue having from 10 to 20 carbon atoms and a sugar residue, and a fatty acid having from 10 to 20 carbon atoms.

[0016] The plant growth promoter of the present disclosure is advantageous from the viewpoint of effectively promoting plant growth.

[0017] FIG. 1 is a diagram schematically showing an example of a plant growth promoter according to the present embodiment. FIG. 2 is a diagram schematically showing another example of a plant growth promoter according to the present embodiment. FIG. 3 is a diagram schematically showing yet another example of a plant growth promoter according to the present embodiment. FIG. 4 is a diagram schematically showing yet another example of a plant growth promoter according to the present embodiment. FIG. 5 is a diagram schematically showing an example of a composition for plant cultivation according to the present embodiment. FIG. 6 is a flowchart showing an example of a plant growth promotion method of the present disclosure. FIG. 7 is a graph showing the fresh weight of spinach in Example 1 and Comparative Example 1. FIG. 8 is a graph showing the cotyledon expansion rate of pansies in Example 2 and Comparative Example 2. FIG. 9 is a total ion chromatogram by liquid chromatography-mass spectrometry of a lipid fraction contained in a cyanobacterial culture supernatant.

[0018] (Knowledge forming the basis of the present disclosure) As the world population grows and demands increased food production, there is a need to develop technologies for efficiently producing high-quality crops on limited arable land. Various types of plant growth promoters have been developed. In particular, plant growth promoters that use plant hormones biosynthesized within plants as active ingredients have a long history. The development of novel technologies for promoting plant growth will broaden the options available to producers.

[0019] In light of these circumstances, the present inventors have conducted extensive research into the development of new technologies for promoting plant growth. As a result, they have newly discovered that specific lipids have a plant growth-promoting effect. Based on this new finding, the present inventors have completed the plant growth promoter disclosed herein. The plant growth promoter disclosed herein can also be referred to as a plant growth stimulant or a plant growth supplement.

[0020] (Embodiments) Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, process sequences, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concepts will be described as optional components. Note that each figure is a schematic diagram and is not necessarily an exact illustration. In each figure, substantially identical components are assigned the same reference numerals, and duplicated descriptions may be omitted or simplified.

[0021] Hereinafter, the embodiments will be specifically described with reference to Figures 1 to 6. Information regarding base sequences or amino acid sequences referred to in this specification is published on the website of the National Center for Biotechnology Information (NCBI), for example, and can be referenced at any time.

[0022] FIG. 1 is a schematic diagram illustrating an example of a plant growth promoter according to the present embodiment. As shown in FIG. 1 , the plant growth promoter 1a contains a lipid 11. The lipid 11 is at least one selected from the group consisting of an acylglycerol containing a fatty acid residue having 10 to 20 carbon atoms and a sugar residue, and a fatty acid having 10 to 20 carbon atoms. The fatty acid may exist as a free fatty acid or as a fatty acid residue contained in an acylglycerol. By including the lipid 11 in the plant growth promoter 1a, plant growth is more likely to be effectively promoted when the plant growth promoter 1a is applied to a plant. Therefore, a plant growth promotion method can be provided, which includes using the plant growth promoter 1a and applying the lipid 11 to a plant.

[0023] The plant growth promoter 1a is not limited to a specific formulation as long as it can be brought into contact with plants. The plant growth promoter 1a may be, for example, a solid containing lipid 11. The plant growth promoter 1a may be, for example, a liquid, in which the lipid 11 is dissolved or dispersed. The plant growth promoter 1a contains a solvent such as water. Examples of formulations of the plant growth promoter 1a include dusts, granules, jet formulations, powders, wettable powders, water-soluble powders, emulsions, liquids, oils, aerosols, microcapsules, and pastes.

[0024] The plant growth promoter 1a may be produced, for example, by a method using biosynthesis, a method using chemical synthesis, or a method using a combination of biosynthesis and chemical synthesis. Production methods using biosynthesis include, for example, a method involving the cultivation of a microorganism or fermentation using a microorganism, and a method of separating and purifying the target substance from an organism by solvent extraction or the like. An example of a microorganism is a cyanobacterium, and it is also possible to use a cyanobacterium that has been genetically modified to secrete a specific lipid component.

[0025] The lipid 11 is not limited to a specific lipid, as long as it is at least one selected from the group consisting of acylglycerols containing a fatty acid residue having 10 to 20 carbon atoms and a sugar residue, and fatty acids having 10 to 20 carbon atoms. The fatty acid contained in the lipid 11 includes, for example, at least one selected from the group consisting of hexadecanoic acid, octadecanoic acid, and 9-octadecenoic acid. The fatty acid residue contained in the acylglycerol includes, for example, at least one selected from the group consisting of residues of hexadecanoic acid, octadecanoic acid, and 9-octadecenoic acid. In this case, plant growth is more likely to be promoted effectively.

[0026] The fatty acids contained in the lipid 11 preferably include hexadecanoic acid, octadecanoic acid, and 9-octadecenoic acid, which is likely to promote plant growth more effectively.

[0027] The sugar residue contained in the lipid 11 includes, for example, a galactose residue, which tends to promote plant growth more effectively.

[0028] The acylglycerol contained in the lipid 11 contains, for example, monogalactosyldiacylglycerol, which is likely to promote plant growth more effectively.

[0029] The monogalactosyldiacylglycerol of the present disclosure has, for example, galactose bound to one carbon atom of glycerol, and a group containing a fatty acid residue bound to the carbon atom of glycerol not bound to galactose. Galactose is preferably bound to the sn-3 position of glycerol. An example of a monogalactosyldiacylglycerol is 1,2-diacyl-3-O-β-D-galactosyl-sn-glycerol. The two fatty acid residues contained in the monogalactosyldiacylglycerol may be the same or different. For example, the fatty acid residue contained in the monogalactosyldiacylglycerol may be a linear molecule or a branched molecule. The fatty acid residue constituting the monogalactosyldiacylglycerol may be, for example, a molecule having an unsaturated bond. Examples of fatty acid residues constituting the monogalactosyldiacylglycerol are hexadecenoic acid, hexadecatrienoic acid, octadecadienoic acid, and octadecatrienoic acid.

[0030] Monogalactosyldiacylglycerol may be produced, for example, by biosynthesis or chemical synthesis. For chemical synthesis of monogalactosyldiacylglycerol, for example, organic chemical synthesis reactions and enzymatic reactions can be used. When monogalactosyldiacylglycerol is produced by chemical synthesis, for example, the monogalactosyldiacylglycerol may have a structure that does not exist in nature.

[0031] The type of monogalactosyldiacylglycerol contained in the lipid 11 may be one type or two or more types.

[0032] The concentration of monogalactosyldiacylglycerol contained in plant growth promoter 1a is not limited to a specific concentration as long as it promotes the growth of at least one organ of a plant. When plant growth promoter 1a is liquid, the concentration of monogalactosyldiacylglycerol can be adjusted appropriately depending on the type of plant to which plant growth promoter 1a is applied, the organ to which plant growth promoter 1a is applied, the growth stage, the cultivation method, the method of applying plant growth promoter 1a, and the plant organ whose growth is promoted by application of plant growth promoter 1a. The concentration of monogalactosyldiacylglycerol contained in plant growth promoter 1a is, for example, 0.001 μg / mL or more. The concentration of monogalactosyldiacylglycerol is, for example, 60 μg / mL or less. The concentration of monogalactosyldiacylglycerol is preferably in the range of 0.01 μg / mL or more and 24 μg / mL or less. The concentration range of monogalactosyldiacylglycerol is more preferably 0.01 μg / mL or more and less than 0.1 μg / mL, more than 0.1 μg / mL and less than 6 μg / mL, and more than 6 μg / mL and less than 24 μg / mL, in which case plant growth can be more effectively promoted without causing phytotoxicity to the plant.

[0033] The plant growth promoter 1a may contain other biomolecules as long as they do not inhibit plant growth. Examples of biomolecules are enzymes, amino acids, ketone bodies, organic acids, p-aminobenzoic acid, spermidine, and nucleic acids. Examples of enzymes are peptidases, nucleases, and phosphatases. An example of a ketone body is 3-hydroxybutyric acid. An example of an organic acid is gluconic acid. Examples of nucleic acids are nucleic acid bases, nucleosides, and nucleotides.

[0034] Plant growth promoter 1a may contain additives as long as it contains lipid 11. Examples of additives include emulsifiers, dispersants, wetting agents, suspending agents, preservatives, propellants, stabilizers, antioxidants, colorants, pH adjusters, penetrants, thickeners, and antifoaming agents. By including additives in plant growth promoter 1a, the properties of plant growth promoter 1a can be adjusted.

[0035] Plant growth promoter 1a can be modified from various perspectives. For example, plant growth promoter 1a may be modified to plant growth promoter 1b shown in FIG. 2, plant growth promoter 1c shown in FIG. 3, and plant growth promoter 1d shown in FIG. 4. Plant growth promoters 1b, 1c, and 1d have the same configuration as plant growth promoter 1a, except for parts that are particularly described. Components of plant growth promoters 1b, 1c, and 1d that are the same as or correspond to components of plant growth promoter 1a are designated by the same reference numerals, and detailed description thereof will be omitted. The description of plant growth promoter 1a also applies to plant growth promoters 1b, 1c, and 1d, unless technically inconsistent.

[0036] Figure 2 is a schematic diagram showing another example of a plant growth promoter according to an embodiment. As shown in Figure 2, plant growth promoter 1b further contains compound 12. Compound 12 is at least one selected from the group consisting of nucleosides and modified nucleosides. With this configuration, plant growth promoter 1b can exhibit a higher plant growth-promoting effect than a plant containing lipid 11 but not compound 12. It is believed that the plant growth-promoting mechanism involving compound 12 does not inhibit the plant growth-promoting mechanism involving lipid 11, and the plant growth-promoting effect is further enhanced by the synergistic effect of both mechanisms.

[0037] Compound 12 is not limited to a specific compound as long as it is at least one selected from the group consisting of nucleosides and modified nucleosides. An example of a modified nucleoside is N-methyl-2-deoxyadenosine. Compound 12 contains at least one selected from the group consisting of N-methyl-2-deoxyadenosine, guanosine, and cytidine. In this case, plant growth promoter 1b is more likely to exhibit a high plant growth-promoting effect.

[0038] Plant growth promoter 1b preferably contains at least one selected from the group consisting of N-methyl-2-deoxyadenosine, guanosine, and cytidine as compound 12. In addition, plant growth promoter 1b contains hexadecanoic acid, octadecanoic acid, and 9-octadecenoic acid as fatty acids contained in lipid 11. With this configuration, plant growth promoter 1b is more likely to exhibit a high plant growth-promoting effect.

[0039] Figure 3 is a schematic diagram showing yet another example of a plant growth promoter according to an embodiment. As shown in Figure 3, plant growth promoter 1c further contains fertilizer component 13. Fertilizer component 13 contains at least one selected from the group consisting of nitrogen, phosphorus, and potassium. With this configuration, application of plant growth promoter 1c to plants can be performed simultaneously with application of fertilizer component 13, thereby reducing the burden on workers engaged in plant growth. For example, in fertilizer component 13, nitrogen is inorganic nitrogen and phosphorus is inorganic phosphorus.

[0040] Fig. 4 is a diagram schematically illustrating yet another example of a plant growth promoter according to an embodiment. As shown in Fig. 4, the plant growth promoter 1d further contains a spreading agent 14. The spreading agent 14 is a known spreading agent. This configuration tends to increase the wettability of the plant growth promoter 1d to plants, and plant growth is likely to be promoted more effectively.

[0041] A plant cultivation composition containing any one of plant growth promoters 1a to 1d and a pesticide can be provided. FIG. 5 is a diagram schematically illustrating an example of a plant cultivation composition 2a according to this embodiment. As shown in FIG. 5, the plant cultivation composition 2a contains a lipid 11 derived from any one of plant growth promoters 1a to 1d, and also contains a pesticide 20. This configuration allows the application of the plant growth promoter to plants to be performed simultaneously with the application of the pesticide 20 to plants, reducing the burden on workers engaged in plant growth. The pesticide 20 is a known pesticide.

[0042] Fig. 6 is a flowchart showing an example of a plant growth promotion method according to the present disclosure. As shown in Fig. 6, this plant growth promotion method includes promoting plant growth by applying lipid 11 to the plant (see step S11). For example, this plant growth promotion method can promote plant growth compared to when the plant is cultivated under the same conditions except that lipid 11 is not applied.

[0043] When lipid 11 is applied to plants, lipid 11 may be used, for example, by diluting it in a liquid or by suspending it in a liquid. The plant growth promotion method includes, for example, applying plant growth promoters 1a to 1d or a composition containing plant growth promoters 1a to 1d to a plant. In the plant growth promotion method, for example, a combination of multiple formulations of plant growth promoters may be applied to a plant.

[0044] In the plant growth promotion method, the lipid 11 may be applied by direct contact with at least a portion of the plant. The lipid 11 may also be applied indirectly to the plant by being applied to soil and nutrient solution that may come into contact with at least a portion of the plant. The method of applying the lipid 11 to the plant may include, for example, at least one method selected from the group consisting of foliar spray, seed treatment, and soil spray. When the lipid 11 is applied to the plant by foliar spray, the lipid 11 can be rapidly absorbed into the plant body from the leaf surface. The lipid 11 can be attached to at least a portion of the seeds before sowing by seed treatment. For example, the lipid 11 can be attached to the seeds by soaking, smearing, or dusting treatment before sowing. When the lipid 11 is applied to the plant by seed treatment, the growth of the plant can be promoted by the lipid 11 from the seed stage and immediately after germination. When the lipid 11 is applied to the plant by soil spray, the lipid 11 can come into contact with the seeds in the soil or the underground parts of the plant. Application of lipid 11 by soil spraying may be carried out, for example, by dripping lipid 11 onto sown seeds so that at least a portion of the seeds is exposed above the soil.

[0045] The plant growth promoting method may include, for example, spraying a liquid plant growth promoter 1a or a composition containing plant growth promoter 1a to a plant. The liquid plant growth promoter 1a or a composition containing plant growth promoter 1a is, for example, attached to the leaves of a plant. For example, the liquid plant growth promoter 1a or a composition containing plant growth promoter 1a is sprayed onto the leaves of a plant. The liquid plant growth promoter 1a or a composition containing plant growth promoter 1a may be included in soil for cultivating a plant. The plant growth promoter 1a may be provided as a solid containing lipid 11, and this solid may be dispersed in water for use.

[0046] The cultivation method of the plant to which the above-mentioned plant growth promotion method is applied is not limited to a specific cultivation method. Cultivation methods include, for example, soil cultivation and hydroponics. Examples of hydroponics include solid medium cultivation and hydroponics.

[0047] The amount of lipid 11 applied to plants is not limited to a specific amount as long as it does not inhibit plant growth. The amount of lipid 11 applied to plants can be adjusted appropriately depending on the type of plant, the organ to which the lipid 11 is applied, the growth stage, the cultivation method, the method for applying the lipid 11, and the plant organ whose growth is promoted by the application of the lipid 11.

[0048] In the plant growth promotion method, the timing of applying the lipid 11 to the plant is not limited to a specific growth stage of the plant, as long as the plant's growth is promoted. The lipid 11 may be applied, for example, to at least one growth stage selected from the group consisting of the dormant stage, vegetative growth stage, and reproductive growth stage of the plant. The lipid 11 may be applied to the plant only once or multiple times. When the lipid 11 is applied to the plant multiple times, the lipid 11 may be applied at multiple growth stages of the plant. The lipid 11 may be applied to the plant regularly or irregularly. For example, the lipid 11 may be applied to the plant once every two weeks by foliar spray, or may be applied to the plant only once by soil spray.

[0049] The plant to which the plant growth promoter, plant cultivation composition, and plant growth promotion method of the present disclosure are applied is not limited to a specific plant. Examples of plants include fruit trees, grains, vegetables, and ornamental plants. The plant is preferably a vegetable or ornamental plant.

[0050] Examples of vegetables are root vegetables, bulbs, beans, cucumbers, solanaceae fruit vegetables, leafy vegetables, and stem vegetables. An example of a bulb is leeks. An example of a solanaceae fruit vegetable is cherry tomatoes. An example of a leafy vegetable is spinach. The vegetables may be vegetables that do not belong to the above categories. An example of a vegetable that does not belong to the above categories is strawberries. An example of a flowering plant is a plant of the Violaceae family. An example of a plant of the Violaceae family is pansies.

[0051] In the present disclosure, promoting plant growth includes, for example, promoting the formation and development of plant organs. Promotion of plant growth can be considered when the formation and development of at least one plant organ is promoted. Examples of plant organs are roots, stems, leaves, flowers, fruits, and seeds. Examples of plant growth promotion include promoting germination, promoting root elongation and thickening growth, promoting an increase in the number of lateral roots, promoting the elongation of stems and leaves, promoting an increase in the number of stems and leaves, promoting stem thickening growth, promoting an increase in leaf area, promoting flowering, promoting an increase in flower size, promoting fruit thickening, promoting an increase in the number of flowers and fruits, promoting an increase in seed size, and promoting an increase in the number of seeds.

[0052] In the present disclosure, plant growth promotion includes, for example, promoting plant growth by suppressing an effect that inhibits plant growth. Plant growth promotion includes, for example, improving anti-stress tolerance in a plant. An effect that inhibits plant growth can occur, for example, under environmental stress conditions and biotic stress conditions. Examples of organisms that can cause biotic stress to plants include pathogens, plants of other species, and plants of the same species. In the present disclosure, pests are not included in the organisms that can cause biotic stress to plants.

[0053] The plant growth promoter, plant cultivation composition, and plant growth promotion method of the present disclosure can promote the growth of vegetables or flowers under environmental stress conditions, for example. Environmental stress is, for example, abiotic stress. Examples of environmental stress include high temperature stress, low temperature stress, drought stress, salt stress, and strong light stress. High temperature stress can occur, for example, when a plant is exposed to a temperature higher than the temperature suitable for growth (e.g., 35°C or higher). Low temperature stress can occur, for example, when a plant is exposed to a temperature lower than the temperature suitable for growth (e.g., 10°C or lower). Drought stress can occur, for example, when the amount of water suitable for plant growth is insufficient due to drought (when stomata close on sunny days). Salt stress can occur, for example, when the salt concentration in the soil in which the plant grows becomes higher than the concentration suitable for plant growth (e.g., when the electrical conductivity (EC) of a water-saturated solution of the soil is 4 dS / m or higher). High light stress occurs when a plant is exposed to light with an intensity higher than that suitable for photosynthesis (for example, when the photon flux density is 1500 μmol / (m 2 This can occur when the time is greater than or equal to 100 s.

[0054] The plant growth promoter, plant cultivation composition, and plant growth promotion method of the present disclosure can promote the growth of plants cultivated under high-temperature stress conditions. High-temperature stress can occur, for example, when the plant's environmental temperature is 35°C or higher. For example, a plant can be considered to be cultivated under high-temperature stress conditions if high-temperature stress is present during at least a portion of the period during which the plant is cultivated. The high-temperature stress tolerance of a plant can be evaluated, for example, by cultivating the plant so that the plant's environmental temperature includes a period of 35°C or higher and 40°C or lower.

[0055] (Other Embodiments) The plant growth promoter, the composition for plant cultivation, and the plant growth promotion method have been described based on the embodiments. However, the present disclosure is not limited to these embodiments. As long as they do not deviate from the gist of the present disclosure, various modifications that a person skilled in the art can conceive of to the embodiments and other forms formed by combining some of the components of the embodiments are included in the scope of the present disclosure.

[0056] (Additional Notes) The above disclosure discloses the following technologies. (Technology 1) A plant growth promoter comprising at least one lipid selected from the group consisting of an acylglycerol containing a fatty acid residue having 10 to 20 carbon atoms and a sugar residue, and a fatty acid having 10 to 20 carbon atoms. (Technology 2) The plant growth promoter according to Technology 1, further comprising at least one compound selected from the group consisting of nucleosides and modified nucleosides. (Technology 3) The plant growth promoter according to Technology 2, wherein the compound comprises at least one selected from the group consisting of N-methyl-2-deoxyadenosine, guanosine, and cytidine. (Technology 4) The plant growth promoter according to any one of Technology 1 to 3, wherein the fatty acid comprises at least one selected from the group consisting of hexadecanoic acid, octadecanoic acid, and 9-octadecenoic acid. (Technology 5) The plant growth promoter according to any one of Technologies 1 to 3, wherein the fatty acid comprises hexadecanoic acid, octadecanoic acid, and 9-octadecenoic acid. (Technology 6) The plant growth promoter according to any one of Technologies 1 to 5, wherein the fatty acid residue comprises at least one selected from the group consisting of residues of hexadecanoic acid, octadecanoic acid, and 9-octadecenoic acid. (Technology 7) The plant growth promoter according to any one of Technologies 1 to 6, further comprising a fertilizer component containing at least one selected from the group consisting of nitrogen, phosphorus, and potassium. (Technology 8) The plant growth promoter according to any one of Technologies 1 to 7, further comprising a spreading agent. (Technology 9) The plant growth promoter according to any one of Technologies 1 to 8, wherein the sugar residue comprises a residue of galactose. (Technology 10) The plant growth promoter according to any one of Technologies 1 to 9, wherein the acylglycerol comprises monogalactosyldiacylglycerol. (Technology 11) The plant growth promoter according to any one of Technologies 1 to 10, which promotes the growth of vegetables or ornamental plants under environmental stress conditions. (Technology 12) The plant growth promoter according to Technology 11, wherein the environmental stress is high temperature stress. (Technology 13) A composition for cultivating plants, comprising the plant growth promoter according to any one of Technologies 1 to 10, and an agrochemical.(Technology 14) A plant growth promotion method comprising promoting plant growth by applying to a plant at least one lipid selected from the group consisting of an acylglycerol containing a fatty acid residue having from 10 to 20 carbon atoms and a sugar residue, and a fatty acid having from 10 to 20 carbon atoms. (Technology 15) The plant growth promotion method according to Technology 14, wherein the sugar residue contains a galactose residue. (Technology 16) The plant growth promotion method according to Technology 14 or 15, wherein the acylglycerol contains monogalactosyldiacylglycerol. (Technology 17) The plant growth promotion method according to any one of Technology 14 to 16, wherein the application includes at least one selected from the group consisting of foliar application, seed treatment, and soil application. (Technology 18) The plant growth promotion method according to any one of Technology 14 to 17, wherein the plant is a vegetable or an ornamental plant. (Technology 19) The plant growth promotion method according to any one of Technology 14 to 17, wherein the plant is spinach. (Technology 20) The plant growth promotion method according to any one of Techniques 14 to 19, wherein the application promotes growth of the plant under environmental stress conditions. (Technology 21) The plant growth promotion method according to Technique 20, wherein the environmental stress is high temperature stress. (Technology 22) The plant growth promotion method according to Techniques 14, 15, 16, 17, 20, or 21, wherein the plant is a pansy.

[0057] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to the following examples.

[0058] (Spinach Cultivation 1) Spinach seeds (variety: Mirage) provided by Sakata Seed Corporation were sown in Tsuchitaro, a culture soil provided by Sumitomo Forestry Landscaping Co., Ltd., and cultivated indoors. In the cultivation of spinach, the indoor temperature was adjusted to about 20°C, and the photon flux density was adjusted to about 120 μmol / (m 2 The plants were exposed to repeated cycles of 12 hours of light and 12 hours of darkness (times 1 second). Five weeks after the start of cultivation, the above-ground parts of the spinach were harvested and their fresh weight was measured. Under these cultivation conditions, no pests were observed, and no feeding damage was observed.

[0059] Example 1 An aqueous solution of monogalactosyldiacylglycerol (MGDG) (CAS number: 1932659-76-1) provided by Avanti Research was prepared as a plant growth promoter. The MGDG used contained multiple types of MGDG, including hexadecenoic acid, hexadecatrienoic acid, octadecadienoic acid, and octadecatrienoic acid as fatty acid residues. The concentration of MGDG in this aqueous solution was 0.375 μg / mL. In the spinach cultivation described above, the plant growth promoter of Example 1 was sprayed on the leaves of eight spinach plants two and four weeks after sowing the spinach seeds to such an extent that the leaves were visually confirmed to be wet.

[0060] (Comparative Example 1) In the above spinach cultivation, water was sprayed onto the leaves of other 8 spinach plants 2 weeks and 4 weeks after sowing the spinach seeds, to an extent that it was visually confirmed that the leaves were wet.

[0061] Fig. 7 is a box plot showing the fresh weight of the above-ground parts of spinach in Example 1 and Comparative Example 1. As shown in Fig. 7, the average fresh weight of the spinach in Example 1 was greater than the average fresh weight of the spinach in Comparative Example 1. Comparing Example 1 and Comparative Example 1, it can be seen that the application of a plant growth promoter containing MGDG as a lipid promoted the growth of the above-ground parts of the plant.

[0062] (Cultivation of pansies) Pansy seeds (variety: F1 Nature Blue Imp) provided by Takii Seed Co., Ltd. were sown in soil (peat moss: vermiculite: perlite: Akadama soil = 6:2:1:1 (volume ratio)) so that part of the seeds were exposed to the soil. After sowing, the seeds were cultivated in an incubator under the light / dark cycle shown in Table 1, including high temperature stress conditions. Eight days after sowing the pansy seeds, the number of individuals with unfolded cotyledons was counted. Under the cultivation conditions, the presence of pests and feeding damage by pests were not confirmed.

[0063]

[0064] Example 2: Several aqueous solutions containing different concentrations of MGDG (CAS No. 1932659-76-1) provided by Avanti Research were prepared as a plant growth promoter. The MGDG used contained several types of MGDG, including hexadecenoic acid, hexadecatrienoic acid, octadecadienoic acid, and octadecatrienoic acid as fatty acid residues. The MGDG concentrations in the solutions were 0.012 μg / mL, 0.023 μg / mL, 0.047 μg / mL, 0.094 μg / mL, 0.19 μg / mL, 0.38 μg / mL, 0.75 μg / mL, 1.5 μg / mL, 3.0 μg / mL, 6.0 μg / mL, 12 μg / mL, and 24 μg / mL. In the cultivation of the pansies described above, the plant growth promoter according to Example 2 was added dropwise to the seeds after sowing at a rate of 1 mL per 2 seeds, and the number of seed samples for each concentration of the plant growth promoter was 24.

[0065] (Comparative Example 2) In the cultivation of the pansies described above, water was dripped onto the seeds after sowing to give 1 mL per 2 seeds, and the number of seed samples was 24.

[0066] (Measurement of Cotyledon Expansion Rate of Pansies) The number of seeds with expanded cotyledons 8 days after sowing was counted among 24 seeds to calculate the cotyledon expansion rate of pansies. The cotyledon expansion rate represents the ratio of the number of seeds with expanded cotyledons to the number of seeds sown.

[0067] Figure 8 is a graph showing the cotyledon expansion rate of pansies in samples according to Example 2. In Figure 8, the vertical axis represents the cotyledon expansion rate of pansies 8 days after sowing, and the horizontal axis represents the concentration (µg / mL) of MGDG contained in the plant growth promoter. The cotyledon expansion rate of the sample according to Comparative Example 2 is plotted in the graph for comparison with Example 2. However, a plant growth promoter containing MGDG was not applied to Comparative Example 2, and the original value on the horizontal axis is 0. Comparing Example 2 and Comparative Example 2, it can be seen that plant growth can be promoted under high-temperature stress conditions by applying a plant growth promoter containing MGDG.

[0068] (Production of plant growth promoter using microorganisms) Plant growth promoter A was produced using cyanobacteria according to the following procedure. -2 PCC 6803 strain was cultured with shaking for 5 days at 30°C while irradiating with light using a white LED under the conditions of 1. The collected cyanobacteria were subjected to Promega's Wizard (registered trademark) Genomic DNA Purification Kit to extract chromosomal DNA from the cells.

[0069]

[0070] Using the above chromosomal DNA as a template, the promoter region of the petE gene, known to be a copper-inducible promoter, was amplified by PCR using Primer 1 (see SEQ ID NO: 1) and Primer 2 (see SEQ ID NO: 2). Toyobo's KOD One® PCR Master Mix -Blue- was used for PCR. The DNA fragment amplified in this manner was designated Fragment 1. Next, two DNA sequences in the upstream region of the slr0688 gene were amplified by PCR using Primer 3 (see SEQ ID NO: 3) and Primer 4 (see SEQ ID NO: 4), as well as Primer 5 (see SEQ ID NO: 5) and Primer 6 (see SEQ ID NO: 6). The DNA fragment amplified using Primer 3 and Primer 4 was designated Fragment 2. The DNA fragment amplified using Primer 5 and Primer 6 was designated Fragment 3. Next, E. coli harboring the pSL2680 plasmid was cultured in LB medium, and the pSL2680 plasmid was extracted. The LB medium contained 1% by mass of triptone, 0.5% by mass of yeast extract, and 1% by mass of NaCl. Using the pSL2680 plasmid as a template, the kanamycin resistance gene was amplified by PCR using primer 7 (see SEQ ID NO: 7) and primer 8 (see SEQ ID NO: 8). The DNA fragment thus amplified was designated as fragment 4.

[0071] The four fragments were ligated together in the following order: 5'-Fragment 2-Fragment 4-Fragment 1-Fragment 3-3' using Clontech's In-Fusion® Snap Assembly Master Mix. Plasmid DNA containing the ligated DNA fragments was transformed using Takara Bio's E. coli HST08 Premium Competent Cells by heat shock. The resulting E. coli was cultured in the presence of 50 μg / mL ampicillin, and the plasmid was extracted using Promega's Wizard® Plus SV Minipreps DNA Purification System to obtain the peptE-slr0688 plasmid used for gene modification.

[0072] Synechocystis sp. PCC6803 cultured as described above was mixed with 3 μg of the peptE-slr0688 plasmid, suspended, and transformed by natural transformation. The resulting culture was applied to a Merck Millipore Immobilon-NC Triton-free MCE 0.45 μm 82 mm disc membrane filter and grown on BG11 agar medium for 2 days. The culture was then transferred to agar medium containing 20 μg / mL kanamycin and grown for 7 days. The resulting mutant colonies were purified to single colonies on BG11 agar medium containing 20 μg / mL kanamycin. This transformation is believed to have resulted in the insertion of the petE gene promoter and kanamycin resistance gene upstream of the slr0688 gene on the chromosomal DNA of the mutant by homologous recombination. The corresponding sequence was amplified from the mutant chromosomal DNA by PCR and confirmed by DNA sequencing. In this way, Synechocystis PpetE-slr0688 strain, which is a mutant strain of Synechocystis sp. PCC6803 strain, was obtained.

[0073] When Synechocystis PpetE-slr0688 strain is cultured in the absence of copper ions, it produces a specific lipid contained in the plant growth promoter in the culture supernatant. Plant growth promoter A was obtained by extracting the specific lipid from the culture supernatant according to the following procedure.

[0074] 100 μmol photons m in a flask containing 200 mL of BG11 medium -2 The Synechocystis PpetE-slr0688 strain was cultured with shaking at 30°C for 5 days while irradiating it with light using a white LED under the conditions of 1. The cells were removed by centrifugation at 20,000 × g for 5 minutes, and the supernatant was filtered through a polyvinylidene fluoride membrane filter with a pore size of 0.22 µm to obtain a culture supernatant.

[0075] Lipids were extracted from the culture supernatant and analyzed by LC-MS to obtain the total ion chromatogram shown in Figure 9. Based on these results, it was confirmed that plant growth promoter A contains MGDG.

[0076] 5 mL of the culture supernatant obtained above was freeze-dried and then added to a solution with a mass ratio of water:chloroform:methanol = 1:1.5:2. The culture supernatant and the solution were thoroughly mixed. The chloroform layer was then recovered and dried under a nitrogen gas spray. In this way, plant growth promoter A, which is the lipid fraction of the culture supernatant, was obtained.

[0077] The plant growth promoter A was treated using a fatty acid methylation kit and a methylated fatty acid purification kit manufactured by Nacalai Tesque. Subsequently, fatty acid species were analyzed using a Shimadzu gas chromatography / mass spectrometry (GC / MS) system, GCMS-QP2010SE. For GC / MS analysis, an InertCap Pure WAX ​​(GL Sciences) column was used, and the linear velocity was adjusted to 30 cm / min. Additionally, the column temperature was programmed to be held at 50°C for 1 minute after sample injection, then increased to 250°C at a heating rate of 8°C / min, and then held at 250°C for 30 minutes. The results are shown in Table 3. Table 3 shows the area ratio of the detection peak for each fatty acid relative to the area value of the detection peak for 9-octadecenoic acid. No other fatty acids were detected other than those listed in Table 3.

[0078]

[0079] (Spinach Cultivation 2) The plant growth promoting effects of the above-mentioned plant growth promoter A, N-methyl-2-deoxyadenosine, guanosine, and cytidine were evaluated in spinach cultivation. Commercially available N-methyl-2-deoxyadenosine, guanosine, and cytidine were used.

[0080] Commercially available culture soil was placed in cultivation pots with a diameter of 12 cm and a height of 10 cm, and three spinach seeds (variety: Mirage) were sown per pot. For the cultivation of spinach, the room temperature was adjusted to 23°C, and the photon flux density of the white light source was 150 μmol / (m 2 The plants were exposed to a cycle of 10 hours of light and 14 hours of darkness (times 10 seconds). Approximately one week after the start of cultivation, when the cotyledons had developed, the plants were thinned out to ensure uniform plant size in each pot. Forty days after the start of cultivation, the spinach was harvested and the height and fresh weight of the above-ground parts of the spinach were measured.

[0081] Spinach plants grown as described above were sprayed with one of the liquids shown in Table 4 on their leaves 11 days and 25 days after sowing, to the extent that wetting of the leaves could be visually confirmed. In the aqueous solutions of Comparative Examples 3B to 3D and the mixed solutions of Examples 3B to 3E, the concentrations of N-methyl-2-deoxyadenosine, guanosine, and cytidine were each 1 nmol / L. The liquids used for foliar spray in Examples 3A to 3E were prepared by suspending plant growth promoter A obtained from 5 mL of culture supernatant in 250 mL of water. Eight spinach plants were grown and examined for each Example and Comparative Example. Table 4 shows the relative values ​​of the average height of the above-ground parts of spinach in each Example and other Comparative Examples, where the average height of the above-ground parts of spinach in Comparative Example 3A was set to "100." In addition, Table 4 shows the relative values ​​of the average fresh weight of spinach in each Example and other Comparative Examples, assuming that the average fresh weight of spinach in Comparative Example 3A was "100."

[0082] As shown in Table 4, in all Examples, the fresh weight and plant height of spinach were increased compared to Comparative Example 3A. Comparative Examples 3B to 3D and Example 3A are compared with Examples 3B to 3E. This shows that the combined use of a nucleoside such as N-methyl-2-deoxyadenosine and plant growth promoter A exhibits a higher plant growth-promoting effect than when the nucleoside and plant growth promoter A are used alone. This suggests that the mechanism of action of the plant growth promoter in plant growth promotion and the mechanism of action of the nucleoside in plant growth promotion do not interfere with each other. It is believed that by combining a plant growth promoter and a nucleoside, their mechanisms of action occur additively or synergistically.

[0083]

[0084] (Cultivation of Cherry Tomatoes) The plant growth promoting effect in the cultivation of cherry tomatoes was evaluated using plant growth promoter A, N-methyl-2-deoxyadenosine, guanosine, and cytidine. As described above, in the cultivation of spinach, the plant growth promoting effect was high in Example 3E, in which a liquid containing all of plant growth promoter A, N-methyl-2-deoxyadenosine, guanosine, and cytidine was sprayed onto the leaves. Therefore, evaluation was performed using a mixed solution of N-methyl-2-deoxyadenosine, guanosine, cytidine, and plant growth promoter A, as in Example 3E.

[0085] Commercially available cherry tomato seedlings were grown in a soil containing 55.6 g / m2 of magnesium carbonate lime. 2 , cottonseed oil cake 111g / m 2 , 8-8-8 chemical fertilizer 111g / m 2 The plants were planted in a greenhouse to which basal fertilizer (total nitrogen: 15.6 kg / 10a, phosphoric acid: 11.1 kg / 10a, potassium: 10.2 kg / 10a) had been applied in advance, with a spacing of 40 cm between plants and 30 cm between rows. At the time of planting, Albarin granules were sprayed. After planting, the cherry tomatoes were managed by single-stemming with all side shoots removed, and cultivated by diagonal training. The cherry tomato fruits were harvested twice a week from 38 days after planting to 100 days after planting, and the number and weight of the cherry tomato fruits were investigated. Top dressing was applied 26 days after planting. For top dressing, 8-8-8 compound fertilizer was applied at 139 g / m 2 (Total: nitrogen: 11.1 kg / 10 a, phosphorus: 11.1 kg / 10 a, potassium: 11.1 kg / 10 a)

[0086] (Example 4) The mixed solution of Example 4, prepared in the same manner as the mixed solution of Example 3E, was sprayed on the leaves of 12 cherry tomato plants once every two weeks after planting the cherry tomato seedlings, to the extent that the leaves could be visually confirmed to be wet.

[0087] (Comparative Example 4) After the above cherry tomato seedlings were planted, water was sprayed on the leaves of other 12 cherry tomato plants once every two weeks to such an extent that it was visually confirmed that the leaves were wet.

[0088] The measurement results of the harvest of cherry tomatoes in Example 4 and Comparative Example 4 are shown in Table 5. The number of fruits harvested from cherry tomatoes in Example 4 was about 28% more than the number of fruits harvested in Comparative Example 4. The difference in the number of fruits harvested per cherry tomato plant in Example 4 and Comparative Example 4 was significant at p<0.05 in Student's t-test. However, there was no significant difference in the average fruit weight.

[0089]

[0090] (Strawberry cultivation) The plant growth promoting effect in strawberry cultivation was evaluated using plant growth promoter A, N-methyl-2-deoxyadenosine, guanosine, and cytidine. As described above, in spinach cultivation, the plant growth promoting effect was high in Example 3E, in which a liquid containing all of plant growth promoter A, N-methyl-2-deoxyadenosine, guanosine, and cytidine was sprayed onto the leaves. Therefore, evaluation was performed using a mixed solution of N-methyl-2-deoxyadenosine, guanosine, cytidine, and plant growth promoter A, as in Example 3E.

[0091] Peat moss, the pH of which had been adjusted to 6.3 to 7.0 using magnesium carbonate lime, was filled into a 30 cm-wide elevated bench and mixed with 50 g of basal fertilizer (High Control Micro: 70-day fertilizer effect type) per 1 m. Commercially available strawberry seedlings (variety: Akihime) were planted in a single row with a spacing of 20 cm between plants. After planting, cultivation was controlled by automatically adding a tap water-diluted solution of liquid fertilizer tank mix F&B provided by OAT Agrio Co., Ltd. The electrical conductivity (EC) of the wastewater from the tap water-diluted liquid fertilizer tank mix F&B was adjusted to 0.4 dS / m. Fruit harvesting began 57 days after planting, and fruit was harvested two to three times per week thereafter for 156 days after planting.

[0092] (Example 5) The mixed solution of Example 5, prepared in the same manner as the mixed solution of Example 3E, was sprayed on the leaves of 20 strawberry plants approximately once every two weeks after planting the strawberry seedlings, to the extent that it was visually confirmed that the leaves were wet.

[0093] (Comparative Example 5) Water was sprayed onto the leaves of another 20 strawberry plants approximately once every two weeks to such an extent that it was visually confirmed that the leaves were wet.

[0094] The measurement results of strawberry harvest in Example 5 and Comparative Example 5 are shown in Table 6. As shown in Table 6, the number of harvested strawberries in Example 5 was about 49% more than the number of harvested strawberries in Comparative Example 5. The difference in the number of harvested strawberries per plant between Example 5 and Comparative Example 5 was significant at p<0.05 by Student's t-test. However, there was no significant difference in the average fruit weight.

[0095]

[0096] (Cultivation of Welsh Onion) The plant growth-promoting effect in the cultivation of Welsh Onion was evaluated using plant growth promoter A, N-methyl-2-deoxyadenosine, guanosine, and cytidine. As described above, in the cultivation of spinach, the plant growth-promoting effect was high in Example 3E, in which a liquid containing all of plant growth promoter A, N-methyl-2-deoxyadenosine, guanosine, and cytidine was sprayed onto the leaves. Therefore, evaluation was performed using a mixed solution of N-methyl-2-deoxyadenosine, guanosine, cytidine, and plant growth promoter A, as in Example 3E.

[0097] Welsh onion (variety: Asagi-kei Kujo) seeds were sown in a cell tray with 200 holes, with approximately 10 seeds per hole, and the cell tray was then maintained inside a greenhouse. 24 days after sowing the welsh onion seeds, 136 g / m of magnesium carbonate lime was added. 2 , cottonseed oil cake 272.7g / m 2 , 8-8-8 chemical fertilizer 181.8g / m 2 Two rows of leeks were transplanted alternately into two ridges that had been previously treated with a basal fertilizer (total of nitrogen: 30.9 kg / 10 a, phosphorus: 20.0 kg / 10 a, potassium: 19.1 kg / 10 a) with a row spacing of 30 cm and a plant spacing of 35 cm. Each ridge was 1.1 m wide and 16 m long. The leeks were harvested 91 days after sowing, and the fresh weight and plant height of the above-ground parts of the leeks were investigated.

[0098] (Example 6) From the 58th day after sowing the green onion seeds, the mixed solution of Example 6 prepared in the same manner as the mixed solution of Example 3E was sprayed on the leaves of a plot 1.1 m wide and 2.0 m long, approximately once every two weeks, to the extent that it was visually confirmed that the leaves were wet.

[0099] (Comparative Example 6) From 58 days after sowing the welsh onion seeds, water was sprayed on the leaves of another plot measuring 1.1 m in width and 2.0 m in length approximately once every two weeks to the extent that it was visually confirmed that the leaves were wet.

[0100] The measurement results of the harvest of leeks in Example 6 and Comparative Example 6 are shown in Table 7. As shown in Table 7, the fresh weight per plant of the leeks in Example 6 was about 16% higher than the fresh weight per plant of the leeks in Comparative Example 6. In addition, the plant height of the leeks in Example 6 was about 9% higher than the plant height of the leeks in Comparative Example 6. These differences in fresh weight and plant height were significant at p<0.05 by Student's t-test.

[0101]

[0102] (Spinach Cultivation 3) The plant growth promoting effect in spinach cultivation when a mixed solution of N-methyl-2-deoxyadenosine, guanosine, cytidine, and plant growth promoter A prepared in the same manner as the mixed solution in Example 3E was mixed with fertilizer and applied was examined by the following procedure.

[0103] Decomposed granite soil was placed in cultivation pots with a diameter of 12 cm and a height of 10 cm, and a commercially available liquid compound fertilizer containing organic components (guaranteed components: total nitrogen 6% by mass, total phosphorus 6% by mass, total potassium 7% by mass) diluted 500 times with water was applied to each pot in an amount of 200 mL. Three spinach seeds (variety: Mirage) were then sown per pot. For spinach cultivation, the room temperature was adjusted to 23°C, and the photon flux density of the white light source was 150 μmol / (m 2The plants were exposed to a cycle of 10 hours of light and 14 hours of darkness (times 10 seconds). Approximately one week after the start of cultivation, the spinach plants were thinned out at the stage when the cotyledons had developed, to ensure that the plants in each pot were of uniform size. Thirty days after the start of cultivation, the spinach plants were harvested and the height and fresh weight of the aboveground parts were measured.

[0104] (Example 7) When applying the liquid compound fertilizer containing organic ingredients to the spinach cultivation described above, a liquid was used in which the liquid compound fertilizer was mixed with 1 mL of the mixed solution of Example 7, which was prepared in the same manner as the mixed solution of Example 3E. This liquid was applied to decomposed granite soil placed in eight pots for cultivating spinach.

[0105] (Comparative Example 7A) When applying the liquid compound fertilizer containing organic ingredients to the spinach cultivation described above, a liquid obtained by mixing the liquid compound fertilizer with 1 mL of water was used. This liquid was applied to the sandy soil placed in another eight pots for spinach cultivation.

[0106] (Comparative Example 7B) In the above spinach cultivation, 200 mL of water was used instead of the organic component-containing liquid compound fertilizer, and this water was applied to the sandy soil contained in another eight pots for spinach cultivation.

[0107] The results of spinach harvest measurements in Example 7, Comparative Example 7A, and Comparative Example 7B are shown in Table 8. As shown in Table 8, the fresh weight per plant of spinach in Example 7 was approximately 35% higher than the fresh weight per plant of spinach in Comparative Example 7A. In addition, the average plant height of spinach in Example 7 was approximately 16% higher than the average plant height of spinach in Comparative Example 7A. Both the fresh weight per plant and the average plant height of spinach were significantly different at p<0.05 in Student's t-test. Considering the results of Comparative Examples 7A and 7B, it appears that in Example 7, both the fertilizer effect of the mixed organic component-containing liquid compound fertilizer and the plant growth promoting effect of the plant growth promoter were exerted. This demonstrates that plant growth promoters can be mixed with fertilizers.

[0108]

[0109] (Spinach Cultivation 4) The plant growth-promoting effect of a mixture of N-methyl-2-deoxyadenosine, guanosine, cytidine, and plant growth promoter A, prepared in the same manner as the mixture of Example 3E, mixed with a spreading agent and applied was examined in spinach cultivation by the following procedure.

[0110] Commercially available potting soil was placed in cultivation pots with a diameter of 12 cm and a height of 10 cm, and three spinach seeds (variety: Mirage) were sown per pot. Cultivation took place in a greenhouse in June. Approximately one week after the start of cultivation, the plants were thinned out when the cotyledons had developed, ensuring uniform plant size in each pot. 28 days after the start of cultivation, the spinach was harvested, and the height and fresh weight of the above-ground parts of the spinach were measured.

[0111] (Example 8A) A mixed solution of Example 8A was prepared in the same manner as the mixed solution of Example 3E. In the above-mentioned spinach cultivation, the mixed solution of Example 8A was sprayed onto the leaves of 24 spinach plants 11 days and 24 days after sowing the spinach seeds to an extent that it was visually confirmed that the leaves were wet.

[0112] (Example 8B) A liquid according to Example 8B was obtained by adding a spreader squash manufactured by Maruwa Biochemical Co., Ltd. to a mixed solution prepared in the same manner as the mixed solution according to Example 3E so as to give a 1000-fold dilution. In the above-described spinach cultivation, the liquid according to Example 8B was sprayed on the leaves of another 24 spinach plants 11 and 24 days after sowing the spinach seeds, to an extent that it was visually confirmed that the leaves were wet.

[0113] (Example 8C) A liquid according to Example 8C was obtained by adding a spreading agent, Mylino, manufactured by Nihon Nohyaku Co., Ltd., to a mixed solution prepared in the same manner as the mixed solution according to Example 3E so as to give a 500-fold dilution. In the above-described spinach cultivation, the liquid according to Example 8C was sprayed on the leaves of another 24 spinach plants 11 and 24 days after sowing the spinach seeds, to an extent that it was possible to visually confirm that the leaves were wet.

[0114] (Comparative Example 8) In the above spinach cultivation, 11 days and 24 days after sowing the spinach seeds, water was sprayed onto the leaves of another 24 spinach plants to an extent that it was visually confirmed that the leaves were wet.

[0115] The results of measuring the yield of spinach in Examples 8A, 8B, 8C, and Comparative Example 8 are shown in Table 9. As shown in Table 9, the fresh weight per plant of spinach in Example 8A was about 32% higher than the fresh weight per plant of spinach in Comparative Example 8. In addition, the average plant height of spinach in Example 8A was about 6% higher than the average plant height of spinach in Comparative Example 8. Similar results were also obtained in Examples 8B and 8C, in which a liquid containing a wetting agent was used for foliar spray. This demonstrates that the plant growth promoter can be mixed with at least the above-mentioned wetting agents. The differences between the fresh weight per plant and the average plant height of spinach in these Examples and those in Comparative Example 8 were significant at p<0.05 by Student's t-test.

[0116]

[0117] (Spinach cultivation 5) The plant growth promoting effect in spinach cultivation when a mixed solution of N-methyl-2-deoxyadenosine, guanosine, cytidine and plant growth promoter A prepared in the same manner as the mixed solution in Example 3E was mixed with a pesticide and applied was verified using the following procedure.

[0118] Commercially available potting soil was placed in cultivation pots with a diameter of 12 cm and a height of 10 cm, and three spinach seeds (variety: Mirage) were sown per pot. Cultivation took place in a greenhouse in June. Approximately one week after the start of cultivation, the plants were thinned out when the cotyledons had developed, ensuring uniform plant size in each pot. 28 days after the start of cultivation, the spinach was harvested, and the height and fresh weight of the above-ground parts of the spinach were measured.

[0119] (Example 9A) A mixed solution of Example 9A was prepared in the same manner as the mixed solution of Example 3E. In the above-described spinach cultivation, the mixed solution of Example 9A was sprayed onto the leaves of 24 spinach plants 11 days and 24 days after sowing the spinach seeds to an extent that it was visually confirmed that the leaves were wet.

[0120] (Example 9B) A liquid according to Example 9B was obtained by adding the pesticide Affirm eclectic manufactured by Syngenta Japan KK to a mixed solution prepared in the same manner as the mixed solution according to Example 3E so that the diluted solution was 2000 times. In the above-described spinach cultivation, the liquid according to Example 9B was sprayed on the leaves of another 24 spinach plants 11 and 24 days after sowing the spinach seeds, to an extent that it was visually confirmed that the leaves were wet.

[0121] (Example 9C) A liquid according to Example 9C was obtained by adding the pesticide Kotetsu Flowable manufactured by Nippon Soda Co., Ltd. to a mixed solution prepared in the same manner as the mixed solution according to Example 3E so as to give a 2000-fold dilution. In the above-described spinach cultivation, the liquid according to Example 9C was sprayed on the leaves of another 24 spinach plants 11 and 24 days after sowing the spinach seeds, to an extent that it was visually confirmed that the leaves were wet.

[0122] (Example 9D) A liquid according to Example 9D was obtained by adding a 4000-fold dilution of the pesticide Colt wettable powder manufactured by Nihon Nohyaku Co., Ltd. to a mixed solution prepared in the same manner as the mixed solution according to Example 3E. In the above-described spinach cultivation, the liquid according to Example 9D was sprayed on the leaves of another 24 spinach plants 11 and 24 days after sowing the spinach seeds to an extent that it was visually confirmed that the leaves were wet.

[0123] (Comparative Example 9) In the above spinach cultivation, 11 days and 24 days after sowing the spinach seeds, water was sprayed onto the leaves of another 24 spinach plants to an extent that it was visually confirmed that the leaves were wet.

[0124] The measurement results of spinach harvest in Examples 9A, 9B, 9C, 9D, and Comparative Example 9 are shown in Table 10. As shown in Table 10, the fresh weight per plant of spinach in Example 9A was about 32% higher than the fresh weight per plant of spinach in Comparative Example 9. In addition, the average plant height of spinach in Example 9A was about 6% higher than the average plant height of spinach in Comparative Example 9. Furthermore, in Examples 9B, 9C, and 9D, in which different formulations of pesticides, i.e., emulsifiable concentrate, flowable concentrate, and wettable powder, were mixed, the fresh weight per plant of spinach and the average plant height of spinach were high, similar to Example 9A. This demonstrated that the plant growth promoter can be mixed with at least the above-mentioned pesticides. The differences between the fresh weight per plant and the average plant height of spinach in these Examples and those in Comparative Example 9 were significant at p<0.05 by Student's t-test.

[0125]

[0126] The plant growth promoter of the present disclosure can be used, for example, as a plant growth promoter for promoting plant growth under optimum temperature conditions and high temperature conditions, thereby improving crop yields.

Claims

1. A plant growth promoter comprising at least one lipid selected from the group consisting of acylglycerols containing a fatty acid residue having 10 to 20 carbon atoms and a sugar residue, and fatty acids having 10 to 20 carbon atoms.

2. The plant growth promoter according to claim 1, further comprising at least one compound selected from the group consisting of nucleosides and modified nucleosides.

3. The plant growth promoter according to claim 2, wherein the compound comprises at least one selected from the group consisting of N-methyl-2-deoxyadenosine, guanosine, and cytidine.

4. The plant growth promoter according to claim 1, wherein the fatty acid includes at least one selected from the group consisting of hexadecanoic acid, octadecanoic acid, and 9-octadecenoic acid.

5. The plant growth promoter according to claim 1, further comprising a fertilizer component containing at least one selected from the group consisting of nitrogen, phosphorus, and potassium.

6. The plant growth promoter according to claim 1, further comprising a wetting agent.

7. The plant growth promoter of claim 1, wherein the sugar residue comprises a residue of galactose.

8. The plant growth promoter according to claim 1, wherein the acylglycerol comprises monogalactosyldiacylglycerol.

9. The plant growth promoter according to claim 8, which promotes the growth of vegetables or ornamental plants under environmental stress conditions.

10. The plant growth promoter according to claim 9, wherein the environmental stress is high temperature stress.

11. A composition for cultivating plants, comprising the plant growth promoter according to claim 1 and an agrochemical.

12. A method for promoting plant growth, comprising applying to a plant at least one lipid selected from the group consisting of acylglycerols containing a fatty acid residue having from 10 to 20 carbon atoms and a sugar residue, and fatty acids having from 10 to 20 carbon atoms, thereby promoting plant growth.

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