Plant growth promoter and plant growth inhibitor, and uses thereof

Abstract

To provide a plant growth inhibitor, and a plant control method that uses the plant growth inhibitor.SOLUTION: A plant growth inhibitor containing dimethylsphingosine is provided. Further provided is a plant control method including a step of treating a target plant using the plant growth inhibitor.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a plant growth promoter and a plant growth inhibitor, and uses thereof. [Background technology]

[0002] Plant growth promoters containing various amino acids have been known. For example, Patent Document 1 discloses that a plant growth promoter containing trehalose and citric acid or a salt thereof is further supplemented with amino acids such as valine, lysine, alanine, cystine, glycine, isoleucine, and proline. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-308434 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of one aspect of the present invention is to provide a plant growth promoter and a plant production method using the same.An object of another aspect of the present invention is to provide a plant growth inhibitor and a pest control method using the same. [Means for solving the problem]

[0005] As a result of extensive research, the present inventors have found that margaric acid, ethyl myristate, and N-acetylmuramic acid have a plant production-promoting effect, and that dimethylsphingosine has a plant growth-inhibiting effect, thereby completing the present invention. One embodiment of the present invention includes the following aspects. <1> A plant growth promoter comprising at least one member selected from the group consisting of margaric acid, ethyl myristate, and N-acetylmuramic acid. <2> <1> A method for producing a plant, comprising a step of treating a target plant with the plant growth promoter described in claim 1. <3> Plant growth inhibitors, including dimethylsphingosine. <4> <3> 10. A plant control method comprising the step of treating a target plant with the plant growth inhibitor described in claim 9. [Effects of the Invention]

[0006] According to one aspect of the present invention, there are provided a plant growth promoter and a plant production method using the same. Also, according to another aspect of the present invention, there are provided a plant growth inhibitor and a control method using the same. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a graph showing the number of lateral roots of Arabidopsis thaliana 7 days after sowing in Example 1. [Figure 2] 1 is a graph showing the root elongation distance of Arabidopsis thaliana 10 days after sowing in Example 1. [Figure 3] 1 is a graph showing the fresh weight of Arabidopsis thaliana 10 days after sowing in Example 2. [Figure 4] FIG. 10 shows images comparing the growth amounts of rice plants photographed 8 days after sowing in Example 3. [Figure 5] 1 is a graph showing the root elongation distance of rice plants photographed 8 days after sowing in Example 3. [Figure 6] 1 is a graph showing the number of lateral roots of Arabidopsis thaliana 7 days after sowing in Example 4. [Figure 7] 1 is a graph showing the fresh weight of the above-ground parts of Arabidopsis thaliana 10 days after sowing in Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0008] [1. Plant growth promoters] A plant growth promoter according to one embodiment of the present invention contains at least one selected from the group consisting of margaric acid (heptadecanoic acid), ethyl myristate, and N-acetylmuramic acid. In this specification, "at least one selected from the group consisting of margaric acid, ethyl myristate, and N-acetylmuramic acid" is also simply referred to as "active ingredient."

[0009] The inventors succeeded in identifying the active ingredient using the following method. First, discarded kelp (the white powdery part of the surface of kelp scraped off and traditionally discarded) was soaked in low-temperature ultrapure water for three days to extract the ingredients. Next, the extracted ingredients were fractionated using high-performance liquid chromatography (HPLC), and the fraction that promotes plant growth was identified using a bioassay. Furthermore, by comparing the fraction with other fractions using a mass spectrometer, the active ingredient specifically present in high concentrations in this fraction was successfully identified. Of the active ingredients, margaric acid and ethyl myristate are believed to be derived from kelp, while N-acetylmuramic acid is believed to be derived from bacteria on the surface of kelp. The active ingredient may be extracted from the discarded kelp described above, or a commercially available product may be used.

[0010] In this specification, the term "plant growth promoter" refers to a substance that is applied to plants for the purpose of promoting plant growth. The plant growth promoter is not particularly limited as long as it satisfies the above definition, and specifically may be a fertilizer, a biostimulant, or the like. The plant growth promoter promotes plant growth by containing the active ingredient.

[0011] The plant growth promoter may contain only one, two, or all three of the active ingredients. When the plant growth promoter contains two of the active ingredients, the combination is not particularly limited and may be any combination. For example, the active ingredients may be N-acetylmuramic acid and margaric acid, margaric acid and ethyl myristate, or ethyl myristate and N-acetylmuramic acid.

[0012] The active ingredient may be determined depending on the intended use of the plant growth promoter. For example, N-acetylmuramic acid significantly promotes lateral root formation compared to margaric acid and ethyl myristate, so if the purpose is to promote lateral root formation, it is preferable to select N-acetylmuramic acid as the active ingredient. Furthermore, if the purpose is to promote root elongation and increase the fresh weight of the aboveground parts, it is preferable to select margaric acid and / or ethyl myristate as the active ingredient.

[0013] The content of the active ingredient relative to the total amount of the plant growth-promoting agent varies depending on the formulation of the plant growth-promoting agent, the target plant to which it is applied, or the production method thereof. In one example, the content of the active ingredient relative to the total amount of the plant growth-promoting agent is preferably 1 to 1,000 μM, more preferably 10 to 500 μM, even more preferably 10 to 300 μM, and particularly preferably 10 μM to 100 μM.

[0014] The plant growth promoter may further contain other common fertilizer components known to those skilled in the art, such as nitrogen, phosphate, potassium, calcium, magnesium, sulfur, iron, manganese, boron, molybdenum, zinc, copper, and chlorine, within the scope of not impairing the effects of the active ingredient.

[0015] The plant growth promoter may further contain other common biostimulant components known to those skilled in the art, provided that the effects of the active ingredient are not impaired. Examples of biostimulant components include humic acid, organic acid materials (e.g., fulvic acid), seaweed, seaweed extracts, polysaccharides, amino acids, peptide materials, minerals, vitamins, microbial materials (e.g., Trichoderma fungi, mycorrhizal fungi, yeast, Bacillus subtilis, rhizobia, etc.), and other components (e.g., functional components derived from plants and animals, microbial metabolites, microbial activating materials, etc.).

[0016] According to the above-mentioned configuration, discarded kelp can be reused to promote plant growth, which can contribute to achieving Sustainable Development Goals (SDGs) such as Goal 2 "Ensure sustainable food production systems" or Goal 12 "Reduce waste generation."

[0017] [2. Plant growth promoter formulation] As long as the plant growth promoter according to one embodiment of the present invention contains the active ingredient, the method for producing it is not particularly limited, and it can be produced by known methods.

[0018] The dosage form of the plant growth promoter is not particularly limited, and examples thereof include granular, solid, powder, liquid, and pellet forms. From the viewpoint of efficient absorption by plants, the liquid form is preferred.

[0019] Examples of solid carriers used in formulation include minerals (kaolin clay, attapulgite clay, bentonite, montmorillonite, acid clay, pyrophyllite, talc, diatomaceous earth, calcite, zeolite, etc.), natural organic substances (corncob flour, walnut shell flour, etc.), synthetic organic substances (urea, etc.), salts (calcium carbonate, ammonium sulfate, etc.), synthetic inorganic substances (synthetic hydrous silicon oxide, etc.), etc. Examples of liquid carriers include water, aromatic hydrocarbons (xylene, alkylbenzene, methylnaphthalene, etc.), alcohols (2-propanol, ethylene glycol, propylene glycol, ethylene glycol monoethyl ether, etc.), ketones (acetone, cyclohexanone, isophorone, etc.), vegetable oils (soybean oil, cottonseed oil, etc.), petroleum-based aliphatic hydrocarbons, esters, dimethyl sulfoxide, acetonitrile, etc.

[0020] The plant growth promoter may contain a surfactant. Examples of the surfactant include anionic surfactants such as alkyl sulfate ester salts, alkylaryl sulfonates, dialkyl sulfosuccinates, polyoxyethylene alkylaryl ether phosphate ester salts, lignin sulfonates, and naphthalene sulfonate formaldehyde polycondensates; nonionic surfactants such as polyoxyethylene alkylaryl ethers, polyoxyethylene alkyl polyoxypropylene block copolymers, and sorbitan fatty acid esters; and cationic surfactants such as alkyltrimethylammonium salts.

[0021] Other than these, water-soluble polymers (polyvinyl alcohol, polyvinylpyrrolidone, etc.), polysaccharides (gum arabic, alginic acid and its salts, carboxymethylcellulose, xanthan gum, etc.), inorganic substances (aluminum magnesium silicate, alumina sol, etc.), preservatives, colorants, stabilizers, etc. may also be used.

[0022] 3. Plant Production Methods A method for producing a plant according to one embodiment of the present invention includes treating a target plant with the plant growth-promoting agent.

[0023] As used herein, the term "target plant" in the plant production method refers to a plant that is to be treated with a plant growth-promoting agent.

[0024] As used herein, the term "plant" refers to a whole plant, a plant organ (e.g., a leaf, a petal, a stem, a fruit, a root, a seed, etc.), a plant tissue (e.g., an epidermis, a phloem, a parenchyma, a xylem, a vascular bundle, a palisade tissue, a spongy tissue, etc.), or a plant cultured cell, or various forms of plant cells, protoplasts, callus, etc.

[0025] The target plant is not particularly limited, and can be applied to plants in general. The target plant may be any of the following plants: spermatophytes, ferns, and bryophytes. The spermatophytes may be angiosperms or gymnosperms. The angiosperms may be monocotyledons or dicotyledons. The target plant may be herbaceous or woody.

[0026] Examples of monocotyledonous plants include Orchidaceae (cypress orchid, moth orchid, vanilla, etc.), Poaceae (rice, wheat, barley, rye, corn, millet, foxtail millet, sugarcane, etc.), Cyperaceae (papyrus, etc.), Araceae (taro, etc.), Alcaligenes (arrowroot, etc.), Liliaceae (tulip, etc.), Amaryllidaceae (onion, leek, garlic, chive), Asparagaceae (asparagus, etc.), Dioscoreaceae (dioscorea, etc.), and Zingiberaceae (ginger, ginger, etc.).

[0027] Dicotyledonous plants include Asteraceae (sunflower, lettuce, burdock, garland chrysanthemum, butterbur, etc.), Fabaceae (soybean, pea, adzuki bean, broad bean, peanut, etc.), Rubiaceae (coffee, etc.), Lamiaceae (perilla, perilla, peppermint, etc.), Euphorbiaceae (poinsettia, cassava, etc.), Malvaceae (cotton, okra, etc.), Apiaceae (carrot, parsley, celery, etc.), Brassicaceae (Arabidopsis, radish, rapeseed, komatsuna, Chinese cabbage, turnip, mustard, cauliflower, cabbage, broccoli, wasabi, radish, etc.), and Rosaceae (strawberry, apple, pear, cherry blossom, plum, etc.). , peaches, etc.), Solanaceae (eggplant, tomato, chili pepper, tobacco, bell pepper, potato, etc.), Amaranthaceae (spinach, etc.), Nymphaeaceae (water lily, water shield, etc.), Nelumbaceae (lotus, etc.), Rutaceae (tangerine, lemon, etc.), Araliaceae (Araliaceae, Aralia elata, etc.), Convolvulaceae (sweet potato, etc.), Cucurbitaceae (watermelon, melon, cucumber, bitter melon, pumpkin, loofah, etc.), Vitaceae (grapes, etc.), Pedaliaceae (sesame, etc.), Caryophyllaceae (gypsophila, carnation, etc.), Violaceae (pansies, etc.), Primulaceae (cyclamen, etc.), Ranunculaceae (Clematis, etc.), etc.

[0028] Furthermore, treating a target plant with a plant growth promoter means applying the plant growth promoter to the target plant.

[0029] The plant growth promoter may be applied to the target plant by applying it to the soil in which the target plant is planted, or by applying it to the surface of the target plant.

[0030] Methods for applying the plant growth promoter to soil include, for example, spraying the plant growth promoter on soil, mixing the plant growth promoter into soil, and irrigating the soil with a chemical solution (chemical solution irrigation, soil injection, chemical solution drip). Specifically, the plant growth promoter may be mixed with an irrigation solution. Examples include injection into irrigation equipment (irrigation tubes, irrigation pipes, sprinklers, etc.), mixing into inter-row water, and mixing into a hydroponic solution. Alternatively, the plant growth promoter may be mixed with an irrigation solution in advance and applied using an appropriate irrigation method such as the above-mentioned irrigation method or other methods such as sprinkling or flooding. When applying the plant growth promoter to soil, the plant growth promoter can be applied, for example, to planting holes, rows, near planting holes, near rows, the entire cultivation area, the plant ground edge, between plants, under tree trunks, main trunk ridges, potting soil, seedling boxes, seedling trays, seedbeds, etc.

[0031] Examples of methods for applying the plant growth promoter to the surface of a target plant include spraying on stems and leaves, spraying on trunks, etc. Other examples include spraying on flowering organs or the entire plant during the flowering period, including before, during, and after flowering. In the case of grains and the like, spraying on ears or the entire plant at the heading stage is also an option. The spraying method is not particularly limited, but specific examples include methods using various sprayers, including helicopters, drones, sprinklers, watering cans, self-propelled and ride-on farming machines, speed sprayers, boom sprayers, and backpack and free-standing power sprayers. When the plant growth promoter is applied to the surface of a target plant, the part of the target plant to which the plant growth promoter is applied is not particularly limited, and may be the entire plant or a portion thereof (stems, leaves, buds, flowers, fruits, ears, seeds, bulbs, tubers, roots, etc.). In this specification, the term "bulb" refers to a bulb, corm, rhizome, tuberous root, and rhizophore.

[0032] Furthermore, the timing for applying the plant growth-promoting agent to the target plant is not particularly limited, and may be at various growth stages of the target plant (germination periods such as before sowing, at the time of sowing, and before or after emergence after sowing; vegetative growth periods such as when raising seedlings, when transplanting seedlings, when taking cuttings or taking cuttings, and growth after planting; reproductive growth periods such as before flowering, during flowering, after flowering, just before heading or at the heading stage; and harvest periods such as before scheduled harvest, before scheduled maturation, and when fruit coloring begins). The timing for applying the plant growth-promoting agent to the target plant is preferably 0 to 30 days after sowing, more preferably 0 to 14 days, and particularly preferably 0 to 10 days after sowing. Applying the plant growth-promoting agent to the target plant 0 to 10 days after sowing can more effectively promote the growth of the target plant. In this specification, seedlings include seedlings, cuttings, etc.

[0033] The frequency and amount of application of the plant growth-promoting agent can be adjusted depending on the concentration of the plant growth-promoting agent and the application method.

[0034] [4. Plant growth inhibitors] A plant growth inhibitor according to one embodiment of the present invention comprises dimethylsphingosine, a compound identified from an extract of discarded kelp in the same manner as the above-mentioned active ingredients.

[0035] As used herein, the term "plant growth inhibitor" refers to a substance that is applied to plants for the purpose of inhibiting plant growth, specifically for the purpose of controlling weeds. The plant growth inhibitor is not particularly limited as long as it satisfies the above definition, and specifically may be a pesticide or the like. A plant growth inhibitor according to one embodiment of the present invention inhibits plant growth by containing dimethylsphingosine.

[0036] The total content of dimethylsphingosine relative to the total amount of plant growth inhibitor varies depending on the formulation of the plant growth inhibitor, the target plant to which it is applied, or the production method thereof. In one example, the total content of dimethylsphingosine relative to the total amount of plant growth inhibitor is preferably 1 to 1,000 μM, more preferably 10 to 400 μM, even more preferably 10 to 300 μM, and particularly preferably 10 μM to 100 μM.

[0037] The plant growth inhibitor may further contain other common growth inhibitor components known to those skilled in the art, as long as the effects of dimethylsphingosine are not impaired. Other growth inhibitors include glufosinate, glyphosate, 2,4-PA dimethylamine, MCPA sodium salt, MCPB, fenothiol, clomeprop, naproanilide, CNP, clomethoxynil, bifenox, MCC, benthiocarb, esprocarb, molinate, butachlor, dimepiperate, DCPA, butachlor, trifluralin, phenmedipham, desmedipham, metribuzin, pretilachlor, bromobutide, mefenacet, dymron, bensulfuron methyl, simetryn, prometryn, dimethametryn, bentazone, oxadiazon, pyrazolate, pyrazoxyfen, benzofenap, trifluralin, piperophos, 2,4-PA dimethylamine, ACN, quizalofop-ethyl, asulam, and pendimethalin.

[0038] 5. Plant growth inhibitor formulations As long as the plant growth inhibitor according to one embodiment of the present invention contains dimethylsphingosine, the method for producing it is not particularly limited, and it can be produced by known methods.

[0039] The dosage form of the plant growth inhibitor is not particularly limited, and examples thereof include granular, solid, powder, liquid, and pellet forms. From the viewpoint of absorption effect into plants, liquid form is preferred.

[0040] The substances used in the formulation may be, for example, those exemplified in [2. Formulation of plant growth promoter].

[0041] 6. Plant Control Methods A plant control method according to one embodiment of the present invention comprises the step of treating a target plant with the plant growth inhibitor.

[0042] As used herein, the "target plant" in the plant control method refers to a plant that is the target of treatment with a plant growth inhibitor. As used herein, the target plant of the control method is intended to be all plants other than the desired cultivated plant, and like the target plant of the production method, it may be any of the following plants: seed plants, ferns, and bryophytes. Examples of target plants of the control method include Gramineae (barnyardgrass, green foxtail, oat, annual bluegrass, etc.), Cyperaceae (Cyperus serotinus, Cyperus serotinus, Cyperus serrata, Bulrush, Euonymus kuroguwai, etc.), Altissimaea (Sagittaria pygmaea, Arrowhead, Arrowhead, etc.), Plantaginaceae (Plantago major, etc.), Commelinaceae (Commonweed, etc.), Asteraceae (Coxbur, ragweed, giant ragweed, artemisia, tall goldenrod, Semen These include dandelion, Bidens frondosa, etc.), Fabaceae (white clover, vetch, etc.), Rubiaceae (cleaver, etc.), Lamiaceae (lamium purpureum, nightshade, etc.), Scrophulariaceae (perfume, etc.), Euphorbiaceae (spurge, etc.), Apiaceae (water dropwort, etc.), Polygonaceae (polygonum sieboldii, willow, knotweed, etc.), Brassicaceae (shepherd's purse, mustard greens, etc.), Solanaceae (nightsnake, etc.), and Caryophyllaceae (chickweed, etc.).

[0043] Furthermore, treating a target plant with a plant growth inhibitor means applying the plant growth inhibitor to the target weed. The application method is not particularly limited, but examples thereof include the application methods exemplified in "3. Plant Production Method."

[0044] The frequency and amount of application of the plant growth inhibitor can be adjusted depending on the concentration of the plant growth inhibitor and the application method.

[0045] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Example]

[0046] An embodiment of the present invention will be described below, but the present invention is not limited to this embodiment.

[0047] Example 1: Evaluation of growth-promoting effect on Arabidopsis thaliana I Discarded kelp, obtained by scraping the surface of the kelp, was soaked in ultrapure water for three days to extract the components contained in the discarded kelp. The extracted components were fractionated by high-performance liquid chromatography (HPLC) and subjected to a bioassay using Arabidopsis thaliana. Based on the bioassay results, the fraction that most strongly promoted plant growth was identified, and five compounds that were specifically abundant in this fraction were identified using a mass spectrometer. Of these five compounds, margaric acid, ethyl myristate, and N-acetylmuramic acid were evaluated for their growth-promoting effects on Arabidopsis thaliana.

[0048] The medium used for sowing Arabidopsis thaliana was 1 / 2 MS medium containing 0.5% by weight sucrose, 0.35% by weight gellan gum, and vitamins (3 g / L thiamine hydrochloride, 5 g / L nicotinamide, 0.5 g / L pyridoxine hydrochloride) at a weight ratio of 1 / 4000.

[0049] Margaric acid (hereinafter also referred to as HA), ethyl myristate (hereinafter also referred to as EM), and N-acetylmuramic acid (hereinafter also referred to as AM) were added to separate 1 / 2 MS media at concentrations of 100 μM each to prepare medium compositions. DMSO was further added to the HA- and EM-added media to a concentration of 0.1 wt%. Each of the prepared medium compositions, as well as the control 1 / 2 MS medium and the 1 / 2 MS medium containing 0.1 wt% DMSO, were poured into separate square Petri dishes (1 cm deep) and allowed to solidify. Thirteen seeds of the wild-type Columbia-0 ecotype of Arabidopsis thaliana were sown in each Petri dish. Six Petri dishes were prepared for each medium.

[0050] Seven days after sowing, the number of lateral roots of Arabidopsis thaliana was measured. The results are shown in Figure 1. Figure 1 is a graph showing the number of lateral roots of Arabidopsis thaliana 7 days after sowing. In Figure 1, error bars represent standard deviation, and n = 30. Significant differences were confirmed using Tukey's Honestly Significantly Different test (HSD test). In Figure 1, different letters (a to c) indicate significant differences with p < 0.05. The values ​​shown in the graph in Figure 1 are relative values ​​when the control is set to 1.0.

[0051] The root length of Arabidopsis thaliana was measured 10 days after sowing. The results are shown in Figure 2. Figure 2 is a graph showing the root length of Arabidopsis thaliana 10 days after sowing. In Figure 2, error bars represent standard deviation, and n = 30. Significant differences were confirmed using Tukey's Honestly Significantly Different test (HSD test). In Figure 2, different letters (a to c) indicate significant differences with each other at p < 0.05. The values ​​shown in the graph in Figure 2 are relative values ​​when the control is set to 1.0.

[0052] <Result> As shown in Figure 1, the number of lateral roots of Arabidopsis thaliana increased when HA, EM, and AM were added to the medium composition compared to 1 / 2MS medium alone. In particular, the number of lateral roots increased significantly when AM was added.

[0053] Furthermore, as shown in Figure 2, the addition of HA, EM, and AM to the medium composition promoted root elongation of Arabidopsis thaliana compared with 1 / 2MS medium alone. Root elongation was particularly pronounced when HA and EM were added.

[0054] Example 2: Evaluation of growth-promoting effect on Arabidopsis thaliana II In Example 2, DMSO was added to the 1 / 2 MS medium used in Example 1 to a concentration of 0.1% by weight. HA and EM were added to separate 1 / 2 MS media to concentrations of 10 μM and 100 μM, respectively, to prepare medium compositions. Each of the prepared medium compositions and a control medium were poured into separate petri dishes (1 cm in diameter) and allowed to solidify. Thirteen seeds of the wild-type ecotype Columbia-0 of Arabidopsis thaliana were sown. Six petri dishes were prepared for each medium.

[0055] Ten days after sowing, the fresh weight of Arabidopsis thaliana was measured using a precision electronic balance (manufactured by Sartorius). The results are shown in Figure 3. Figure 3 is a graph showing the fresh weight of Arabidopsis thaliana 10 days after sowing. In Figure 3, error bars represent standard deviation, n = 30. Significant differences were confirmed by Tukey's HSD test. In Figure 3, different letters (a, b) indicate significant differences with each other at p < 0.05.

[0056] <Result> As shown in Figure 3, when the concentrations of HA or EM in the medium composition were 10 µM and 100 µM, the fresh weight of Arabidopsis increased compared to when 1 / 2 MS medium was used alone.

[0057] Example 3: Evaluation of growth-promoting effect in rice The medium used was the 1 / 2 MS medium used in Example 2. HA or EM was added to separate 1 / 2 MS media to a concentration of 100 μM to prepare medium compositions. Each of the prepared medium compositions and a control medium were poured into separate hydroponic containers, and 30 seeds of the rice cultivar Koshihikari were sown in each container.

[0058] Eight days after sowing, the rice plants were harvested and the total length and root length were evaluated. The results are shown in Figures 4 and 5. Figure 4 shows an image of rice plants photographed eight days after sowing. Figure 5 is a graph showing the root length of rice plants eight days after sowing. In Figure 5, the error bars represent standard deviation, and n = 30. Significant differences were confirmed by Tukey's Honestly Significantly Different test. The values ​​shown in the graph in Figure 5 are relative values ​​when the control is set to 1.0.

[0059] <Result> As shown in Figure 4, rice growth was promoted when HA or EM was included in the medium composition compared to 1 / 2MS medium alone. Furthermore, as shown in Figure 5, rice root elongation was promoted when HA or EM was included in the medium composition compared to 1 / 2MS medium alone.

[0060] Example 4: Evaluation of growth inhibitory effect on Arabidopsis thaliana Of the components contained in the fraction identified in Example 1, dimethylsphingosine (hereinafter also referred to as DS) was evaluated for its growth-promoting effect on Arabidopsis thaliana.

[0061] The 1 / 2 MS medium used in Example 2 was used as the medium. DS was added to separate 1 / 2 MS media to give concentrations of 10 μM and 100 μM, respectively, to prepare medium compositions. Each of the prepared medium compositions and a control medium were poured into separate square Petri dishes (1 cm deep) and allowed to solidify. 13 seeds of the wild-type Columbia-0 Arabidopsis thaliana ecotype were sown in each Petri dish. Six Petri dishes were prepared for each medium.

[0062] The number of lateral roots of Arabidopsis thaliana was evaluated 7 days after sowing. The results are shown in Figure 6. Figure 6 is a graph showing the number of lateral roots of Arabidopsis thaliana 7 days after sowing. In Figure 6, the error bars represent standard deviation, n = 30. Significant differences were confirmed using Tukey's HSD test (Tukey's Honestly Significantly Different test).

[0063] Ten days after sowing, the fresh weight of the above-ground parts of Arabidopsis was measured using a precision electronic balance (manufactured by Sartorius). The results are shown in Figure 7. Figure 7 is a graph showing the fresh weight of the above-ground parts of rice 10 days after sowing. In Figure 7, error bars represent standard deviation, n = 30. Significant differences were confirmed by Tukey's HSD test. In Figure 7, different letters (a to c) indicate significant differences with each other at p < 0.05.

[0064] <Result> As shown in Figure 6, when the DS concentration in the medium composition was 10 μM or 100 μM, the number of lateral roots of Arabidopsis thaliana did not increase compared to when 1 / 2 MS medium was used alone. Furthermore, as shown in Figure 7, the growth of the aboveground parts of Arabidopsis thaliana was suppressed depending on the DS concentration in the medium composition compared to when 1 / 2 MS medium was used alone. [Industrial Applicability]

[0065] The present invention can be used in the production or control of plants.

Claims

1. Plant growth inhibitors, including dimethylsphingosine.

2. A method for controlling plants, comprising the step of treating a target plant with the plant growth inhibitor according to claim 1.

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